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Home My WebLink AboutAPA356ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTTASK6 -DEVELOPMENTSELECTIONSUBTASK6.05DEVELOPMENTSELECTIONREPORT,K~Ol35ACRESAMERICANINCORPORATED1577CStreetSuite305Anchorage,Alaska99501Telephone:(907)279-9631FINALREPORTDECEMBER1981ACRESAMERICANINCORPORATED1000LibertyBankBuildingt~ainatCourtBuffalo,NewYork14202Telephone:(716)853-7525 ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTSUSITNABASINDEVELOPMENTSELECTIONVOLUMEI -MAINREPORTTABLEOFCONTENTSPageLISTOFTABLES..........................................................iiiLISTOFFIGURES..................................................•.......vii1 -INTRODUCTION1•1-TheStudyArea................................................1-11.2-ProjectDescription1-21.3-ObjectivesandScopeofCurrentStudies.................•.....1-21.4-PlanFormulationandSelectionProcess........................1-51.5-OrganizationofReport1-72 -SUMMARY2.1-ScopeofWork2-12.2-PreviousStudies..•.•.•..........-~•..................2-12.3-Rai1be1tLoadForecasts................•......••..~2-22.4-Railbe1tSystemandFuturePowerGeneratingOptions...........2-42.5-SusitnaBasin..2-52.6-SusitnaBasinDevelopmentSelection...........................2-92.7-SusitnaHydroelectricDevelopment2-112.8-ConclusionsandRecommendations2-123 -SCOPEOFWORK3.1-DevelopmentSelectionStudies...•..........•..................3-13.2-ContinuedEngineeringStudies3-34 -PREVIOUSSTUDIES4.1-EarlyStudiesofHydroelectricPotential4-14.2-U.S.BureauofReclamation-1953Study4-24.3-U.S.BureauofReclamation-1961Study~.................4-24.4-AlaskaPowerAdministration-1974........................•...4-24.5-KaiserProposalforDevelopment..•..•.......••.•..............4-24.6-U.S.ArmyCorpsofEngineers-1975and1979Studies4-35 -RAILBELTLOADFORECASTS5.1-Introduction5-15.2-E1ectricityDemandProfiles........................ ...........5-25.3-ISERElectricityConsumptionForecasts...••••.•.••............5-25.4-PastProjectionsofRailbe1tElectricity......................5-65.5-DemandForecasts..............................................5-75.6-PotentialforLoadManagementandEnergyConservation5-85.7-LoadForecastsUsedforGenerationPlanningStudies5-9i ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTSUSITNABASINDEVELOPMENTSELECTIONVOLUMEI -MAINREPORTTABLEOFCONTENTS(Cont.)6 -RAILBELTSYSTEMANDFUTUREPOWERGENERATINGOPTIONSPage6.1-Introduction..................................................6-16.2-ExistingSystemCharacteristics...............................6-26.3-Fairbanks-AnchorageIntertie................................6-36.4-HydroelectricOptions.........................................6-46.5-ThermalOptions,•...........·...................................6....76.6-ImpactoftheFuelUseAct....................................6-126.7-OtherOptions;~...............6-147 -SUSITNABASIN7.1-Introduction..................................................7-17.2-ClimatologyandHydrology.....................................7-17.3-Regiana1Geo109Y.. . . . . . . . . . •. . . . . . . . . . . . . . . . . . . . . . . •. . . . . . . . . .7-47.4-SeismicAspects...•.....'..'....7-67.5-EnvironmentalAspects.........................................7-98 -SUSITNABASINDEVELOPMENTSELECTION8.1-Terminology'.;..................................8-18.2-PlanFormulationandSelectionMethodology...............••...8-18.3 -DamSiteSe1ection...................•................. .. .... .8-28.4-SiteScreening................................................8-48.5-EngineeringLayoutandCostStudies...........................8-58.6-FormulationofSusitnaBasinDevelopmentPlans................8-128.7-EvaluationofBasinDevelopmentPlans.........................8-198.8-ComparisonofGenerationScenariosWithandWithouttheSusitnaBasinDevelopmentPlan................................8-299 -SUSITNAHYDROELECTRICDEVELOPMENT9.1 -SelectedPlan..'........................... ......... .... .......9-19.2-ProjectDescription...........................................9-19.3-ConstructionSchedules........................................9-99.4-OperationalAspects...........................................9-109.5-EnvironmentalReview;........................9-1110-CONCLUSIONSANDRECOMMENDATIONS10.1-Conclusions..................................................10-110.2-Recommendations'....................................10-2i i LISTOFTABLESNumber5.15.2TitleHistoricalAnnualGrowthRatesofElectricUtilitySales......................•........5-12AnnualGrowthRatesinUtilityCustomersandConsumptionPerCustomer5-13UtilitySalesbyRailbeltRegions5-14RailbeltElectricityEnd-UseConsumption(GWh)5-15Base CaseForecast(MES-GM)(GWh).....•......••......5-165.35.45.55.6SummaryofRailbeltElectricityProjections5-175.7SummaryofRecentProjectionsofRailbeltElectricPowerRequirements(GWh)5-185.8PerformanceofPastProjectionsRailbeltElectricPowerRequirements5-195.9ForecastTotalGenerationandPeakLoads-TotalRailbeltRegion..................•.............5-205.10RailbeltRegionLoadandEnergyForecastsUsedForGenerationPlanningStudies...........•..........5-216.1TotalGeneratingCapacityWithintheRailbeltSystem.................................•..•..........6-166.26.36.46.56.67.17.2GeneratingUnitsWithintheRailbelt-19806-17OperatingandEconomicParametersforSelectedHydroelectricPlants6-19ResultsofEconomicAnalysesofAlternativeGenerationScenarios6-20SummaryofThermalGeneratingResourcePlantParameters...................•...................••..6-21AlaskanFuelReserves.............................•..6-22SummaryofClimatologicalData7-18RecordedAirTemperaturesatTalkeetnaandSummitinof••.•.•.••••••.•••••••••••••.•••••••••.•••7-19iii LISTOFTABLES(Cont'd.)Number7.37.47.57.67.7TitleMaximumRecordedIceThicknessontheSusitnaRiver7-20AverageAnnualandMonthlyFlowatGageintheSusitnaBasin7-21FloodPeaksatSelectedGagingStationsontheSusitnaRiver7-22SuspendedSedimentTransport7-23DifferentVegetationTypesFoundintheSusitnaBasine-•••••••••••••••••••••••••••••••••••••••••••••••7-248.1PotentialHydroelectricDevelopment8-328.2CostComparisons8-338.3DamCrestandFullSupplyLevels8-348.4CapitalCostEstimateSummariesSusitnaBasinDamSchemesCostin$Million19808-358.5ResultsofScreeningModel8-368.6InformationontheDevilCanyonDamandTunnelSehemes8-378.7DevilCanyonTunnelSchemesCosts,PowerOutputandAverageAnnua1Energy8-388.8CapitalCostEstimateSummariesTunnelSchemesin$Mi11ion19808-398.9SusitnaDevelopmentPlans8-408.10EnergySimulationSensitivity8-438.11SusitnaEnvironmentalDevelopmentPlans8-448.12AnnualFixedCarryingCharges8-478.13ResultsofEconomicAnalysesofSusitnaPlans-MediumLoadForecast8-488.14ResultsofEconomicAnalysesofSusitnaPlans-LowandHighLoadForecast8-49iv LISTOFTABLES(Cont'd.)Number8.158.16TitlePageResultsofEconomicSensitivityAnalysesforGenerationScenarioIncorporatingSusitnaBasinDevelopmentPlan1.3-MediumForecast8-50EconomicBackupDataforEvaluationofPlans8.17EconomicEvaluationofDevilCanyonDamandTunnelSchemesandWatana/DevilCanyonandHighDevilCanyon/VeePlans.....................•....8-528.18EnvironmentalEvaluationofDevilCanyonDamandTunne1Scheme8-538.19SocialEvaluationofSusitnaBasinDevelopmentSchemes/Plans8-548.20EnergyContributionEvaluationoftheDevilCanyonDamandTunne1Schemes8-558.21OverallEvaluationofTunnelSchemesandDevilCanyonDamScheme8-568.22EnvironmentalEvaluationofWatana/DevilCanyonandHighDevilCanyon/VeeDevelopmentPlans8-578.23EnergyContributionEvaluationoftheWatana/DevilCanyonandHighDevi1Canyon/VeePlans8-598.24OverallEvaluationoftheHighDevilCanyon/VeeandWatana/Devi1CanyonDamPlans8-608.25ResultsofEconomicAnalysesforGenerationScenarioIncorporatingThermalDevelopmentPlan-MediumForecast8-618.26EconomicSensitivityofComparisonofGenerationPlanwithWatana/DevilCanyonandtheAllThermalPlan8-628.27SocialComparisonofSystemGeneratingPlanwithWatana/DevilCanyonandtheAllThermalPlan8-638.28GenericComparisonofEnvironmentalImpactsofaSusitnaBasinHydroDevelopmentVersusCoalFiredThermalGenerationintheBelugaCoalFields8-64v LISTOFTABLES(Cont'd.)8.29OverallEvaluationsofAllThermalGenerationPlanswiththeGenerationPlanIncorporatingWatana/DevilCanyonDams8-65Number9.19.29.310.1TitleOutflowsfromWatana/DevilCanyonDevelopmentStage1Watana400MW9-15OutflowsfromWatana/DevilCanyonDevelopmentStage2Watana800MW......................•.........9-16OutflowsfromWatana/DevilCanyonDevelopmentStage3DevilCanyon400MW9-17EnergyandCapacityForecastsfor201010-4vi LISTOFFIGURESviiDataCollectionStations..............•..............7-251-12Paqe-'-RelativeDensitiesofMoose-November,19807-29AverageAnnualFlowDistributionWithintheSusitnaRiverBasin7-26AllThermalGenerationScenario-MediumLoadForecast6-28WinterDistributionofMoose-March,19807-30EnergyForecastsUsedForGenerationPlanningStud;es5-24Regiona1Geology7-28ForecastAlternativeTotalRailbeltUtilitySales5-23DamsitesProposedbyOthers4-4HistoricalTotalRailbeltUtilitySalestoFinalCustomers5-22LocationMap6-23MonthlyAverageFlowsintheSusitnaRiveratGoldCreek7-27GenerationScenarioIncorporatingThermalandAlternativeHydropowerDevelopments-MediumLoadForecast6-26FormulationofPlansIncorporatingAll-ThermalGeneration6-27FormulationofPlansIncorporatingNon-SusitnaHydroGeneration6-24SelectedAlternativeHydroelectricSites6-25LocationMap...........•..............................1-10PlanFormulationandSelectionMethodology1-11PlanningApproachTitle5.25.37.17.27.47.57.67.31.11.21.34.15.16.66.56.36.46.16.2Number LISTOFFIGURES(Cont'd.)Number7.78.1TitlePageLocationandTerritorialBoundariesofWolfPacks-19807-31SusitnaBasinPlanFormulationandSelectionProcess8-669.1WatanaFillDamPreliminaryConstructionSchedule....9-188.13GenerationScenariowithSusitnaE1.3-HighLoadForecast8-788.10GenerationScenariowithSusitnaE2.3-MediumLoadForecast8-758-698-708-71viiiStage1 -WatanaReservoir(400MW)OperationoftheWatana/DevilCanyonDevelopmentPlanE1.39-20Stage3 -WatanaReservoir(800MW)OperationoftheWatana/DevilCanyonDevelopmentPlanE1.39-21DevilCanyonThinArchDamPreliminaryConstructionSchedu1e9-19GenerationScenariowithSustinaE1.3-MediumLoadForecast8-74DamsiteCostvsReservoirStorageCurvesCapitalCostvsEnergyPlotsforEnvironmentalSusitnaBasinPlans8-73DamsiteCostvsReservoirStorageCurvesMutuallyExclusiveDevelopmentAlternatives'8-68SchematicRepresentationofConceptualTunnelSchemes8-72DamsiteCostvsReservoirStorageCurvesProfileThroughAlternativeSites8-679.49.39.28.12GenerationScenariowithSusitnaE1.5-LoadLoadForecast8-778.11GenerationScenariowithSusitnaE3.1-MediumLoadForecast8-768.98.88.28.38.48.58.68.7 LISTOFFIGURES(Cont'd.)Number9.59.69.79.8TitlePage--"'--Stage3 -DevilCanyonReservoir(400MW)OperationoftheWatana/DevilCanyonDevelopmentPlanEl.39-22Discharge-StageFrequencyCurveSusitnaRiveratGo1dCreek9-23Discharge-StageFrequencyCurveSusitnaRiveratSusitnaStation9-24Discharge-StageFrequencyCurveSusitnaRiveratSunshine9-25ix LISTOFPLATESNumber12345678910111213TitlePageDevilCanyonHydroDevelopmentFillDam8-79WatanaHydroDevelopmentFi11Dam8-80WatanaStagedFi11Dam8-81HighDevilCanyonHydroDevelopment8-82SusitnaIIIHydroDevelopment"8-83VeeHydroDevelopment8-84Dena1i&Mac1arenHydroDevelopments8-85PreferredTunnelScheme3PlanViews8-86PreferredTunnelScheme3Sections8-87Devi1CanyonScheme1PlanandSection9-26Devi1CanyonScheme1Sections9-27WatanaScheme2...............................•......9-28WatanaScheme2Sections9-29x INTRODUCTIONThisreporthasbeenpreparedbyAcresAmericanIncorporated(Acres)onbehalfoftheAlaskaPowerAuthority(APA).ThereportessentiallyrepresentsamilestoneinthePlanofStudy(POS)fortheSusitnaHydroelectricProjectcurrentlybeingundertakenbyAcresunderthetermsofanAgreementwithAPAdatedDecember19,1979.TheSusitnaPOSwasfirstissuedinFebruary1980andsubsequentlyrevisedinSeptember1980.ItdescribesindetailthemanyandcomplexstudiestobeundertakenfromJanuary1980throughJune1982toassessthefeasibilityandtheenvironmentalimpactoftheproposedSusitnaProject.ThePOSalsoaddressestherequirementsforfilingaFERClicenseapplicationshouldprojectfeasibilityandenvironmentalacceptabilitybeestablished.StudiesthroughMarch1981havemainlybeenconcernedwithevaluationoftheneedforelectricpowerintheAlaskaRailbeltRegionandconsiderationofthealternativesformeetingthesepowerneedsbothwithandwithoutaSusitnaBasinhydroelectricdevelopment.ThisDevelopmentSelectionReportpresentstheresultsofthisinitialstepinthePOSprocess,andprovidesrecommendationsandjustificationforcontinuationofstudyofaspecificbasindevelopment.TheremainderofSection1ofthisreportdealswithadescriptionofthestudyareaandtheproposedSusitnadevelopmentandasummaryoftheobjectivesandscopeofthecurrentstudies.1.1-TheStudyAreaThemainstreamoftheSusitnaRiveroriginatesabout90milessouthofFair-b~nkswheremeltingglacierscontributemuchofitssummerflow(seeFigure1.1).Meanderingforthefirst50milesinasoutherlydirectionacrossabroadlluvialfanandplateau,itturnswestwardandbeginsa75mileplungebetweenssentiallycontinuouscanyonwallsbeforeitchangescoursetothesouthwestridflowsforanother125milesinabroadlowland.Formorethan30years,theasthydroelectricpotentialofthisriverhasbeenrecognizedandstudied.trategicallylocatedintheheartoftheSouthCentralRailbelt,theSusitnaauldbeharnessedtoproduceabouttwiceasmuchelectricalenergyperyearas~~.nowbeingconsumedintheRailbelt.h.eSusitnaRiversystem,withadrainageareaofmorethan19,000squaremiles,·~rthesixthlargestinAlaska.MajortributariesincludetheYentna,Chulitna,alkeetna,andTyonerivers.Asubstantialportionofthetotalannualstream-1m"occursduringspringandsummerandisgeneratedbyglacialmeltandainfallrunoff.Thewaterduringthisperiodisturbid.Winterflowsconsist!mostentirelyofgroundwatersupplyandaregenerallyfreeofsediment.reezeupstartsinOctoberintheupperreachesofthebasin,andbylateovembericecovershaveformedonallbutthemostrapidlyflowingstretchesofheriver.BreakupgenerallyoccursaroundearlyMay.heSusitnaRiveranditstributariesareimportantcomponentsofAlaska1sighlyprolificfisheryresource.Salmon,DollyVardentrout,grayling,and~hitefisharefoundwithintheBasin.Waterfowlhabitatintheglacialoutwashplainsupportstrumpeterswanandmigratoryfowl.Bear,moose,andcaribouthrivethere.Inshort,wildliferesourcesareplentiful.Extensivestudies1-1 arenecessarybothtodeterminetheirtotalvalue,theimpactswhichanydevelopmentmayhaveuponthem,andthenatureofmitigativemeasureswhichmightbetakentoeliminateoroffsetnegativeenvironmentalconsequencesofhydroelectricdevelopment.1.2-ProjectDescriptionTheSusitnaBasinhasbeenunderstudysincethemid-fortiesbyagenciessuchastheWaterResourcesandPowerServices(WRPS,formerlytheUSBR),theAlaskaPowerAdministration,andtheUSArmyCorpsofEngineers(COE),aswellasH.J.KaiserandCompany.ThemorerecentandmostcomprehensiveofthesestudieswerecarriedoutbytheCOE.Theoptimummethodofdevelopingthebasin'spotentialwasdeterminedbytheCOEtocomprisetwomajorhydroelectricdevelopments.ThefirstofthesewouldrequireadamatWatanaandthesecond,adamatDevilCanyon.ThisdevelopmentwasfoundtobeeconomicallyviableandwouldprovidetheRailbeltareawithalong-termsupplyofrelativelycheapandreliableenergy.StudiescompletedbyAcrestodatehaveconfirmedthatthepreferreddevelopmentshouldconsistoftwolargehydroelectricdamsatWatanaandDevi1Canyon(seeFigure1.1).TheWatanadamwouldbeconstructedfirst.Itwouldinvolveafilldamroughly880feetmaximumheight,andbecauseofthelargereservoirvolumecreatedwouldpro~ideadequatestorageforseasonalregulationoftheflow.Initially,400MWofgeneratingcapacitywouldbeinstalledatthissite.Thiswouldlaterbeexpandedtoaround800MWtoallowforadditionalpeakingcapacity.TheDevilCanyondamwouldbethenextstageofthedevelopment.Itwouldinvolvea675feetmaximumheightdoublecurvatureconcretearchdamandincorporatea400MWpowerhouse.Thetotalaverageannualenergyyieldfromthisdevelopmentamountsto6200GWh.ThepowerfromthetotaldevelopmentwouldbeconveyedtotheRailbeltsystembyasmanyasfour345kVtransmissionlinesrunningfromtheprojectsitestotheproposedAnchorage-FairbanksintertieinthevicinityofGoldCreek.Thecapacityofthecurrentlyenvisagedintertiewouldultimatelybeincreasedtoatotaltransmissioncapabilityoftwo345kVlinesfromAnchoragetoFairbanks.Accesstotheprojectsiteisstillunderstudy.Alternativeroutesbeingcon-sideredincludearoadaccessfromtheeastviatheDenaliHighway,andrailandroadaccessfromthewestviatheParksHighway,andtherailroadpassingthroughGoldCreek.Itisenvisagedthatsubstantialairsupportwouldbere-quiredduringtheconstructionoftheprojectandanairstripwouldbeconstructedneartheWatanasite.Thecurrentschedulecallsforthefirst400MWatWatanatobeon-lineby1993.Theadditional400MWatWatanawouldbecommissionedasrequiredandprobablybebroughton-linein1996.TheDevilCanyondevelopmentwouldbebroughton-lineintheyear2000.1.3-ObjectivesandScopeofCurrentStudiesTheprimaryobjectivesofthestudiesare:-Toestablishtechnical,economic,andfinancialfeasibilityoftheSusitnaprojecttomeetfuturepowerneedsoftheRailbeltregion;1-2 evaluatetheenvironmentalconsequencesofdesigningandconstructingtheSusitnaproject;FileacompletedlicenseapplicationwiththeFederalRegulatoryCommissioninJune1982.overallscopeofworkinvolvesabroadrangeofcomprehensivefieldandicestudiesovera30monthperiodfromJanuary1980toJune1982.Thesebeendividedintospecifictasksandarediscussedbrieflybelow.TheportionoftheworkisbeingconductedbyAcreswiththesupportofalsubcontractors.Task1 -PowerStudiesThesestudiesinvolvethedevelopmentofarangeofpowerandenergypro-jectionsfortheRailbeltarea.Theenergyforecastworkhasbeenunder-takenbytheInstituteforSocialandEconomicResearch(ISER)undercontracttoAPA.WoodwardClydeConsultants(WCC),undersubcontracttoAcres,producedtheassociatedloaddurationcurvesandpowerforecasts.Task2 -SurveysandSiteFacilitiesThistaskincludestheconstructionandmaintenanceofa40manfieldcamplocatedattheWatanasiteandtheprovisionofaircraftandhelicoptersupporttothefieldteams.ThecampconstructionandmaintenanceisbeingundertakenbyCookInletRegion,Inc.(CIRI),andHolmesandNarver,Inc.(H&N)undersubcontracttoAcres.LocalaircraftcompaniesareprovidingfixedwingandhelicoptersupportalsoundersubcontracttoAcres.AlsoincludedinthistaskisanextensiverangeofsurveyandmappingworkbeingundertakenbyR&MConsultants,Inc.forAcresandancillarystudiesdealingwithsiteaccess,landstatus,andreservoirclearingstudies.Task3 -HydrologyThistaskincorporatesanextensivefielddatacollectionprogrambeingconductedbyR&Mandassociatedofficestudiesrequiredfortheprojectwhicharebeing conductedjointlybyR&MandAcres.Task4-SeismicStudiesThisworkincorporatesawiderangeoffieldandofficestudiesaimedatdevelopinganunderstandingoftheseismicsettingandpotentialearthquakemechanismsoftheregionanddeterminingtheseismicdesigncriteriaforthestructurestobebuilt.MostofthisworkisbeingconductedbyWCCundersubcontracttoAcres.Task5-GeotechnicalExplorationThistaskincorporatesallthegeotechnicalexplorationfieldworkcon-ductedattheWatanaandDevilCanyondamsites.MuchofthefieldworkisbeingcarriedoutbyR&MundersubcontracttoAcres.1-3 (f)Task6 -DesignDevelopmentThistaskincorporatestheplanningandengineeringstudiesforselectingthemostappropriateSusitnaBasindevelopmentplanandforproducingtheconceptualengineeringdesignsfortheselecteddevelopment.Thisworkcanbedividedintotwostages:(i)Stage1 -DevelopmentSelectionThisphaseoftheworkencompassestheriverbasinplanningandRail-beltsystemgenerationplanningworkaimedatdeterminingthemostappropriatebasindevelopmentplan.(ii)Stage2 -FeasibilityDesignThisphaseincludesthemoredetailedengineeringstudiesaimedatoptimizingtheselectedprojectandproducingtheconceptualdesignsforinclusionintheFERClicense.(g)Task7 -EnvironmentalStudiesThesestudiesencompassabroadrangeoffieldandofficestudiesaimedatdeterminingpotentialenvironmentalimpactsduetotheprojectandde-velopingappropriatemitigatingmeasures.Muchofthisworkisbeingcon-ductedundersubcontractforAcresbyTerrestrialEnvironmentalSpecialists(TES).ThelargegameandfisheriesstudiesarebeingconductedbyTheAlaskaDepartmentofFishandGame(ADF&G)underareimbursableserviceagreementwithAPA.(h)Task8 -TransmissionThistaskincludesthestudiesnecessarytodevelopconceptualdesignsforthetransmissionsystemrequiredtoconveySusitnapowerintotheRailbeltsystem.ThisworkisbeingconductedbyAcreswithsomesupportfromR.W.RetherfordandAssociates(RWRA),adivisionofInternationalEngineeringCompany(IECO).(i)Task9 -ConstructionCostEstimateandSchedulesThisworkinvolvestheproductionofdetailedconstructiontypecostesti-matesandconstructionschedulesoftheprojectandisbeingconductedbyAcreswithsomeassistancefromF.MoolinandAssociates(FMA).(j)Task10-LicensingThistaskcoverstheworkrequiredtoproducetheFERClicensedocumentsandisbeingcarriedoutbyAcres.(k)Task11-MarketingandFinancingThistaskincludessupportstudiesdealingwiththeriskandfinancialas-pectsassociatedwiththeproject.ThesestudiesarerequriedtoidentifyandsecurethenecessaryfundingfortheprojectandarebeingcarriedoutbyAcreswithsupportfromspecialistconsultants.1-4 Task12-PublicParticipationProgramAPAisconductinganextensivepublicparticipationprogramtokeepthepublicinformedontheprogressandfindingsofthestudyandtoobtainfeedbackfromthemonissuestheybelievearecriticaltothesuccessfulimplementationoftheproject.AcresandthesubcontractorssupportAPAintheseactivitiesonanasrequiredbasis.Task13-AdministrationThistaskdealswiththeAcresadministrationoftheentirestudyeffort.-PlanFormulationandSelectionProcesselementinthestudiesbeingundertakenistheprocesswhichisbeingedforformulationandcomparisonofdevelopmentplans.Muchemphasisisplacedonconsiderationofeveryimportantperspectivewhichmayinfluenceselectionofaparticularcourseofactionfromanumberofpossiblealter-ives.Adescriptionofthegenericplanformulationandselectionmetho-ispresentedinAppendixA.AnessentialcomponentofthisplanningriY'('lr~(~c:isageneralizedmulti-objectivedevelopmentselectionmethodologyforngtheplanningdecisions.Asecondimportantfactoristheformulationofistentandrationalapproachtotheeconomicanalysesundertakenbythees.PlanningMethodologyAgeneralizedplanformulationandselectionprocesshasbeendevelopedtoguidethevariousplanningstudiesbeingconducted.Ofnumerousplanningdecisionstobemadeinthesestudies,perhapsthemostimportantaretheselectionofthepreferredSusitnaBasindevelopmentplan(Task6),andappropriateaccessandtransmissionlineroutes(Tasks2and8).Thebasicapproachinvolvestheidentificationoffeasiblecandidatesandcoursesofaction,followedbythedevelopmentandapplicationofanappropriatescreeningprocess.Inthescreeningprocess,lessfavorablecandidatesareeliminatedonthebasisofeconomic,environmental,socialandotherprescribedcriteria.Plansarethenformulatedwhichincorporatetheshortlistedcandidatesindividuallyorinappropriatecombinations.Finally,amoredetailedevaluationoftheplansiscarriedout,againusingprescribedcriteriaandaimedatselectingthebestdevelopmentplan.Figure1.2illustratesthisgeneralprocess.Inthefinalevaluation,noattemptismadetoquantifyalltheattributesusedandtocombinetheseintoanoverallnumericalevaluation.Instead,theplansarecomparedutilizingbothquantitativeandqualitiveattri-butes,andwherenecessary,judgementaltradeoffsbetweenthetwotypesaremadeandhighlighted.Thisallowsreviewersoftheplanningprocesstoquicklyfocusonthekeytradeoffsthateffecttheoutcomeofthedeci-sions.Tofacilitatethisprocedure,apairedcomparisontechniqueisusedsothatatanyonestepintheplanningprocess,onlytwoplansarebeingevaluated.1-5 ThestudiesaimedatselectingthebestSusitnaBasindevelopmentplaninvolveconsiderationofalargenumberofalternativecoursesofaction.Theselectionprocesshasbeenusedinthreeparallelapplicationsinanattempttosimplifytheprocedure.TwoRailbeltatingscenarios,oneinvolvingonlythermalgeneratingunitsandasecondinvolvingamixofthermalandotherpotential(non-Susitna)hydrodevelopmentswereevaluatedseparately,aswellasaSusitna/thermalscenario.InformationonthesealternativegeneratingscenariosisnecessarytomakeapreliminaryassessmentofthefeasibilityoftheIIwithSusitnallgeneratingscenariobymeansofacomparisonofthethreedifferentscenarios.Figure1.3graphicallyillustratestheoverallplanningprocess.Steps1to5oftheformulationandselectionmethodologyareappliedtodevelopingaplanincorporatingall-thermalgenerationandaplan.incorporatingnon-Susitnahydrogeneration.ThesestudiesareoutlinedinSection6ofthisreport.ThesamefivestepsarealsoappliedtothedevelopmentofthebestIIwithSusitnallgeneratingscenarioasoutlinedinSection8.Thefinalcomparisonorevaluationofthethreescenariosiscarriedoutusingacompressedformatofthemethodologyasaguidelinetoyieldtherequiredpreliminaryfeasibilityassessment.ThisaspectofstudyiscoveredattheendofSection8.(b)EconomicAnalysesAstheproposedSusitnadevelopmentisapublicorStateproject,allplanningstudiesdescribedarebeingcarriedoutusingeconomicparametersasabasisofevaluation.ThisensuresthatresultinginvestmentdecisionsmaximizeoenefitstotheStateasawholerather.thananyindividualgroup..orgroupsofresidents.Theeconomic.ana,lysesincorporatethefollowingprinciples:(i)Intra-statetransferpaymentssuchastaxesandsubsidiesareexcluded;(ii)Opportunityvaluesareusedestablishthecostsforcoal,oilandnaturalgasresourceiusedforpowergenerationinthealternativesconsidered.Theseopportunicostsarebasedonwhattheopenmarketispreparedtopayfantheseresources.TheythereforereflectthetruevalueoftheseresourcestotheState.Theseanalysesignoretheexistenceofcurrentterm-contractualcommitmentswhichmayexist,andwhichfixresourcecostsatvaluesdifferentfromtheopportunitycosts;(iii)Theanalysesare.conductedingllreallloriationadjustedparameters.Thismeansthatinterestorscountrateusedequalstheassessedmarketrateminusthegeneralrateofinflation.Similarly,the;fuelandconstructioncostescalationratesareadjustedtoreflecttherateoverorunderthegeneralinflationrate;1-6 (iv)Themajorimpactcausedbytheuseoftheseinflationadjustedpara-metersistoimprovetherelativeeconomicsofcapitalintensivepro-jects(suchashydrogeneration)versusthehighfuelconsumptionpro-jects(suchasthermalgeneration).Italsoleadstotheselectionoflargereconomicoptimumsizesofthecapitalintensiveprojects.TheseshiftstowardsthecapitalintensiveprojectsareconsistentwithmaximizingtotalbenefitstotheState.-OrganizationofReportobjectiveofthisreportistodescribetheresultsofSusitnaBasindevel-~~n~'>Tselectionstudies,i.e.Task6,Stage1.ItalsobrieflyoutlinesthetsofsomeoftheearlyTask6,Stage2engineeringstudiesaimedatrefin-theproject'sgeneralarrangements.ordertoimprovereadibilityofthereport,muchofthedetailedtechnicalialaswellasthereviewofthestatusoftechnicalsupportstudiesisin-inaseparatevolumeofappendices.Thereportisorganizedasfollows:1 -Main1:Introduction2:SummarycontainsacompletesummaryofSections4through10ofthemain3:ScopeofWorksectionoutlinesthescopeofworkassociatedwiththeresultspresentedinreport.PreviousStudiesssectionbrieflysummarizespreviousSusitnaBasinstudiesbyothers.5:RailbeltLoadForecastssection,theresultsoftheenergyandloadforecaststudiesundertakenISERandweearesummarized.ItconcludeswithadiscussionoftherangeofforecastsusedintheSusitnaBasinplanningstudies.RailbeltSystemandFuturePowerGeneratingOptionssectiondescribescurrentlyfeasiblealternativesconsideredinthisstudygeneratingelectricalenergytomeetfutureRailbeltneeds.Itincorporatesaontheperformanceandcostsofthefacilities.7:SusitnaBasinsectionprovidesadescriptionofthe physicalattributesoftheSusitnaincludingclimatologic,hydrologic,geologic,seismic,andenvironmental1-7 Section8:SusitnaBasinDevelopmentSelectionTheSusitnaBasinplanningstudiesandtheRailbeltsystemgenerationplanningworkcarriedoutarediscussedinthissection.ItincludesadescriptionoftheSusitnaBasindevelopmentselectionprocessandpreliminaryassessmentoftheeconomicandenvironmentalfeasibilityoftheselectedWatana/DevilCanyonhydropowerdevelopment.Section9:SusitnaHydroelectricDevelopmentThissectiondescribes,inmoredetail,theselectedWatana/DevilCanyonprojectandincludesadiscussionoftheresultsofthepreliminaryoperationalstudiesandasummaryenvironmentalreviewoftheproject.Theprojectgeneralarrange-mentsdescribedresultfrominitialTask6,Stage2engineeringstudiesandthereforepresentamoreup-to-datepicturethanthearrangementsdescribedinSection8.Section1U:ConclusionsandRecommendationsInthissectionrecommendationsaremadefortheSusitnaBasindevelopmentplanconsideredbyAcrestomeritfurtherstudy.Italsodealswithtentativecon-clusionswithrespecttotheproject1stechnical,environmental,andeconomicfeasibility.Volume2 -AppendicesA:PlanFormulationandSelectionProcessAdescriptionofthegenericapproachtositescenarios,planformulationandplanevaluationispresented.B:ThermalGeneratingSourcesThisappendixoutinesthedetailedbackuptothethermalgeneratingunitper-formanceandcostinformationpresentedinSection6ofthemainreport.C:AlternativeHydroGeneratingSourcesThestudiesundertakentoproducetheshortlistofalternativehydrodevelop-mentsdiscussedinSection6,i.e.thoseoutsidetheSusitnaBasin,aredes-cribedinthisappendix.D:EngineeringLayoutuesignAssumptionsThisappendixdescribesthedesignassumptionsthatweremadeinordertodeveloptheengineeringlayoutsforpotentialpowerdevelopmentprojectsattheDevilCanyon,HighDevilCanyon,Watana,SusitnaIII,Vee,Maclaren,andDenalisites.E:SusitnaBasinScreeningModelHereadescriptionispresentedofthecomputermodelusedtoscreenoutuneco-nomicbasindevelopmentplans,asdiscussedinSection8.1-8 SingleandMulti-ReservoirHydropowerSimulationStudiescomputermodelusedtosimulatethemonthlyenergyyieldfromthevariousitnadevelopmentplansisdescribedinthisappendix.Detailsarepresentedtheaveragemonthlyfirmandaverageyieldsforthedevelopmentplansdiscus-inSection8ofthemainreport.SystemwideEconomicEvaluation(OGP5)sappendixcontainsthedetailedbackupinformationtothecomputermodelusedintheeconomicevaluationofthevariousgeneratingscenariosconsid-intheplanningstudies.EngineeringStudiesbackupstudiestotheprojectgeneralarrangementsdescribedinSection9ofmainreportarepresentedinthisappendix.EnvironmentalStudiessappendixcontainsthedetailedbackupdataonenvironmentalaspectsgather-duringthecourseofinvestigationsandbythevarioussubcontrac-1-9 LOCATIONMAP1-1020020jill,~~!~~;~~~~60SCALEINMILESIFIGURE INPUT FROM AVAILABLE SOURCES -PREVIOUS AND CURRENT STUDIES ...... I............ DEFINE OBJECTIVES SELECT CANDIDATES FEEDBACK FEEDBACK PLAN FORMULATION AND SELECTION METHODOLOGY LEGEND t\.STEP NUMBER IN --..I~STANDARD PROCESS (APPENDIX A ) FIGURE I.2 IJ~lm I 1-.... I I-' N DEVELOPMENT OF AN ALL THERMAL GENERATING PLAN DEVELOPMENT OF AN OTHER HYDRO GENERATING PLAN DEVELOPMENT OF A SUSITNA BASIN GENERATING PLAN DEVELOPMENT OF THE BEST GENERATING SCENARIO LEGEND I > o PLANNING APPROACH APPLICATION OF PLAN FORMULATION AND SELECTION METHODOLOGY END PRODUCTS FIGURE 1.3 11~lm I -SUMMARY-ScopeofWorkScopeofWorkdiscussedintheDevelopmentSelectionReportincludestheopmentselectionstudiesandpreliminaryengineeringstudiesaimedatningthegeneralarrangementsoftheselectedWatanaandDevilCanyondamnV'r"Ot'Ts.ThedevelopmentselectionstudiesconstituteStage1oftheTask6designstudiesasdescribedintheAcresPOS,andincludethefollowing:a)ReviewofPreviousStudiesandReports(Subtask6.01)b)InvestigateTunnelAlternatives(Subtask6.02)c)EvaluateAlternativeSusitnaDevelopments(Subtask6.03)d)WatanaandDevilCanyonStagedDevelopment(Subtask6.06)e)ThermalGeneratingResources(Subtask6.32)f)HydroelectricGeneratingSources(Subtask6.33)g)EnvironmentalAnalysis(Subtask6.34)h)LoadManagementandConservation(Subtask6.35)i)GenerationPlanning(Subtask6.36)j)DevelopmentSelectionReport(Subtask6.05)thedevelopmentselectionstudieswerefinalizedworkcontinuedonengineer-ingdesignstudiesaimedatrefiningthegeneralarrangementsattheDevilCan-yonandWatanasites.Thesestudiesinvolvedtheproductionofalternativegeneralarrangementsincorporatingearth/rockfillandconcretearchdamsatbothWatanaandDevilCanyon.Thesearrangementswerecostedandevaluatedtodeterminewhichisthemostappropriate.DesignworkisbeingcarriedoutontheproposedthinarchdamatDevilCanyontoensurethatsuchastructurecansafelywithstandtheanticipatedseismic1oading.Extensiveusewasmadeofcomputerstressanalysesinthedesignstudies.2.2-PreviousStudiesShortlyafterWorldWarIIhadended,theUSBRconductedaninitialinvestiga-tionofhydroelectricpotentialinAlaska,reportingitsresultsin1948.Res-pondingtoarecommendationin1949bythenineteenthAlaskaterritoriallegis-laturethatAlaskabeincludedintheBureauofReclamationprogram,theSecre-taryofInteriorprovidedfundstoupdatethe1948work.ThereSUltingreport,issuedin1952,recognizedthevasthydroelectricpotentialwithintheterri-tory.ParticularemphasiswasplacedonthestrategiclocationoftheSusitnaRiverbetweenAnchorageandFairbanksaswellasitsproximitytotheconnectingRailbelt(seeFigure1.1).Aseriesofstudieswascommissionedovertheyearstoidentifydamsitesandconductgeotechnicalinvestigations.By1961,theDepartmentoftheInteriorproposedauthorizationofthetwodampowersysteminvolvingtheDevilCanyonandtheDenalisites.Thedefinitive1961reportwassubsequentlyupdatedbytheAlaskaPowerAdministration(atthattimeanagencyoftheBureauofReclamation)in1974,atwhichtimethedesirabilityofproceedingwithhydroelectricdevelopmentwasreaffirmed.2-1 TheCOEwasalsoactiveinhydropowerinvestigationsinAlaskaduringthe1950'sand1960's,butfocuseditsattentiononamoreambitiousdevelopmentatRampartontheYukonRiver.ThisprojectwascapableofgeneratingfivetimesasmuchelectricenergyasSusitnaannually.Thesheersizeandthetechnologicalchal-lengesassociatedwithRampartcapturedtheimaginationofsupportersandeffectivelydivertedattentionfromtheSusitnaBasinformorethanadecade.TheRampartreportwasfinallyshelvedintheearly1970'sbecauseofstrongenvironmentalconcernsanduncertaintyofmarketingprospectsforsomuchenergy,particularlyinlightofabundantnaturalgaswhichhadbeendiscoveredanddevelopedinCookInlet.TheenergycrisisoccasionedbytheOPECoilboycottin1973providedsomefurtherimpetusforseekingdevelopmentofrenewableresources.FederalfundingwasmadeavailabletocompletetheAlaskaPowerAdministration'supdatereportonSusitnain1974andtolaunchaprefeasibi1ityinvestigationbytheCOE.TheStateofAlaskaitselfcommissionedareassessmentoftheSusitnaProjectbytheHenryJ.KaiserCompanyin1974.AlthoughthegestationperiodforapossibleSusitnaProjecthasbeenlong,Federal,State,andprivateorganizationshavebeenvirtuallyunanimousovertheyearsinrecommendingthattheprojectproceed.2.3-Rai1be1tLoadForecastsThefeasibilityofamajorhydroelectricprojectdependsinpartupontheextenttowhichtheavailablecapacityandenergyareconsistentwiththeneedsofthemarkettobeservedbythetimetheprojectcomesonline.Attemptingtofore-castfutureenergydemandisadifficultprocessatbest.Itisthereforepar-ticularlyimportantthatthisexercisebeaccomplishedinanobjectivemanner.ForthisreasonAPAandtheStateofAlaskajointlyawardedaseparatecontracttoISERtoprepareappropriateprojectionsfortheAlaskaRai1be1tregion.(a)ElectricityDemandProfilesBetween1940and1978,electricitysalesintheRailbeltgrewatanaverageannualrateof15.2percent.Thisgrowthwasroughlytwicethatforthenationasawhole.NationalandAlaskanannualgrowthratesfordifferentperiodsbetween1940and1978,andthehistoricalgrowthofRai1be1tutilitysalesfrom1965consistentlyexceededthenationalaverage.How-ever,thegaphasbeennarrowingduetothegradualmaturingoftheAlaskaneconomy.GrowthintheRai1be1thasexceededthenationalaveragefortworeasons;thepopulationgrowthintheRai1be1thasbeenhigherthanthenationalrate,andtheproportionofAlaskanhouseholdsservedbyelectricutilitieswaslowerthantheU.S.averagesothatsomegrowthinthenumberofcustomersoccurredindependentlyofpopu1ationgrowth.(b)ISERElectricityConsumptionForecastsTheISERelectricitydemandforecastingmodelconceptualizedincomputerlogicthelinkagebetweeneconomicgrowthsecnariosandelectricityconsumption.Theoutputfromthemodelisintheformofprojectedvaluesofelectricityconsumptionforeachofthethreegeographicalareasofthe2-2 Railbelt(GreaterAnchorage,GreaterFairbanksandGlennallen-Valdez)andisclassifiedbyfinaluse(i.e.,heating,washing,cooling,etc.)andconsumingsector(commercial,residential,etc).Themodelproducesoutputonafive-yeartimebasisfrom1985to2010,inclusive.TheISERmodelconsistsofseveralsubmodelslinkedbykeyvariablesanddrivenbypolicyandtechnicalassumptionsandstateandnationaltrends.Thesesubmodelsaregroupedintofoureconomicmodelswhichforecastfuturelevelsofeconomicactivityandfourelectricityconsumptionmodelswhichforecasttheassociatedelectricityrequirementsbyconsumingsectors.Fortwooftheconsumingsectorsitwasnotpossibletosetupcomputermodels;thereforesimplifyingassumptionsweremade.TheoverallapproachtoderivationofthepeakdemandforecastsfortheRailbeltRegionwastoexaminetheavailablehistoricaldatawithregardtothegenerationofelectricalenergyandtoapplytheobservedgenerationpatternstoexistingsalesforecasts.InformationroutinelysuppliedbytheRailbeltutilitiestotheFederalEnergyRegUlatoryCommissionwasutilizedtodeterminetheseloadpatterns.Theanalysisofloadpatternsemphasizedtheidentificationofaveragepatternsoverthe10-yearperiodfrom1970to1979anddidnotconsidertrendsorchangesinthepatternswithtime.Generally,theuseofaveragevalueswaspreferredasitreducedtheimpactofyearlyvariationsduetovariableweatherconditionsandoutages.Inanyevent,itwasnotpossibletodetectanyconsistentpatternsintheavailabledata.TheaveragehourlydistributionofgenerationforthefirstweeksofApril,AugustandDecemberwasusedtodeterminethetypicalaverageloadpatternforthevariousutilities.Asaresultoftherelativelylimiteddatabase,thecalculatedloaddurationcurvewouldbeexpectedtoshowlessvariationthanonecomputedfromamorecompletedatabase,resultinginanoverestimationoftheloadfactor.Inaddition,hourlydataalsotendtoaverageoutactualpeakdemandsoccurringwithinatimeintervaloflessthanonehour.Thiscouldalsoleadtooverestimationoftheloadfactor.Itis,however,consideredthattheaccuracyachievedisadequateforthesestudies,particularlyinlightoftherelativelymuchgreateruncertaintiesassociatedwiththeloadforecasts.LoadForecastsUsedforGenerationPlanningStudiesThreeISERenergyforecastswereconsideredingenerationplanningstudies.Theseincludethebasecase(MES-GM)ormediumforecast,alowandahighforecast.ThelowforecastisthatcorrespondingtotheloweconomicgrowthasproposedbyISERwithanadjustmentforlowgovernmentexpenditure(LES-GL).ThehighforecastcorrespondstotheISERhigheconomicgrowthscenariowithanadjustmentforhighgovernmentexpenditure(HES-GH).Electricityforecastsderivedinthisstudyrepresenttotalutilitygenera-tionandincludeprojectionsforself-suppliedindustrialandmilitarygenerationsectors.Inc1udedintheseforecastsaretransmissionanddis-tributionlossesintherangeofbetween9and13percent,dependinguponthegenerationscenarioassuned.Theseforecasts,rangingfrom2.71to4.76percentaverageannualgrowth,wereadjustedforuseingenerationplanningstudies.2-3 Thelowforecastcaseassumedaboveincorporatesanannualgrowthrateof2.71percent.Thisratewouldbereducedwithenforcementofenergycon-servationmeasuresmoreintensivethanthosepresentlyinuseintheState.N!annualgrowthrateof2.1percentwasjudgedtobeareasonablelowerlimitforelectricaldemandforpurposesofthisstudy.Thisrepresentsa23percentreductioningrowthratewhichissimilartothereductiondevelopedinanindependentstudyauthorizedbytheState.Theimplementationofloadmanagementmeasureswouldresultinanaddi-tionalreductioninpeakloaddemand.Theresidentialsectordemandisthemostsensitivetoashiftofloadfromthepeakperiodtotheoff-peakperiod.Overthe1980-2010period,anannualpeakloadgrowthrateof2.73percentwasusedinthelowforecastcase.Withloadmanagementmeasuressuchasratereformandloadcontrols,thisgrowthratecouldbereducedtoanestimated2.1percent.Theannualloadfactorforyear2010wouldbeincreasedfrom62.2percentinthelowforecastto64.4percentinthelowestcase.2.4-RailbeltSystemandFuturePowerGenerationOptionsIfconstructed,theSusitnaBasindevelopllentplanwouldprovideamajorportionoftheRailbeltRegionenergyneedswellbeyondtheyear2000.Itisclearlyimportanttodeterminethemosteconomicbasindevelopllentplanwhichclearlydefinesdetailssuchasdamheights,installedgeneratingcapacities,reservoiroperatingrules,danandpowerhousestagingconcepts,andconstructionsche-dules.Toaccomplishthis,itisfirstnecessarytoevaluateineconomictermstheplaninthecontextoftheentireRailbeltgeneratingsystem.ThisrequiresthateconomicanalysesbeundertakenofexpansionalternativesforthetotalRailbeltsystemcontainingseveraldifferenttypesofgeneratingsources.Thesesourcesincludeboththermalandhydropowergeneratingfacilitiescapableofsatisfyingaspecifiedloadforecast.EconomicanalysesofscenarioscontainingalternativeSusitnaBasindevelopllentplansbeinginvestigatedwouldthenrevealwhichisthemosteconomicbasindevelopllentplan.Thisprocessandthecompar-isonofotherfactorssuchasenvironmentalimpactsandsocialpreferencesessentiallyfallswithinthepurviewof"generationplanning".Thesesystemwidegenerationplanningstudiesrequireacomprehensiveprocessofassemblingthenecessaryinformation.Thisinformationincludesanassessmentoftheexistingsystemcharacteristics,theplannedAnchorage-Fairbanksinter-tie,anddetailsofvariousgeneratingoptionsincludinghydroelectricandthermal.TheimplicationsoftheFuelUseAct(FUA),andconsiderationofotheroptionssuchastidalandgeothermalenergygenerationarealsoimportantfac-tors.Performanceandcostinformationrequiredforthegenerationplanningstudieshavebeendevelopedforthehydroelectricandthermalgenerationoption~butnotforthetidalandgeothermaloptions.Preliminaryindicationsarethattheseoptionsareasyetnotcompetitivewiththemoreconventionaloptionsconsidered.ThetwomajorloadcentersoftheRailbeltRegionaretheAnchorage-CookInletareaandtheFairbanks-TananaValleyarea.Atpresent,thesetwoareasoperateindependently.TheexistingtransmissionsystembetweenAnchorageandWillowconsistsofanetworkof115kVand138kVlineswithinterconnectiontoPalmer2-4 Fairbanksisprimarilyservedbya138kVlinefromthe28MWcoal-firedplantatHealy.CommunitiesbetweenWillowandHealyareservedbylocaldistribution.Therearecurrentlynineelectricutilities(includingtheAlaskaPowerAdministration)providingpowerandenergytotheRailbeltsystem.Withtheexceptionoftwohydroelectricplants,thetotalRailbeltinstalledcapacityof944MWasof1980consistsoffifty-onethermalgenerationunitsfiredbyoil,gasorcoal.Engineeringstudiesarecurrentlybeingundertakenforconstructionofaninter-tiebetweentheAnchorageandFairbankssystems.Aspresentlyenvisaged,thisconnectionwillinvolvea138kVtransmissionlinebetweenWillowandHealyandwouldprovidecapabilityfortransferring50MWofcapacityatanytime.Itisscheduledforcompletionin1984.Currentintertiestudiesindicatethatitiseconomictoconstructthisintertiesuchthatitcanbeupgradedtothe375kVSusitnatransmissioncapabilitywhenWatanacomesonline.Itwasconcludedthatafullyinterconnectedsystemshouldbeassumedforallthegenerationplanningstudiesoutlinedinthisreport,andthattheintertiefacilitieswouldbecommontoallgenerationscenariosconsidered.Inthepre-liminarycomparisonsofalternativegenerationscenarios,thecostofsuchintertiefacilitieswasalsoassumedtobecommon.However,infinalcompari-sonsofalessernumberofpreferredalternativescenarios,appropriateconsid-erationwasgiventorelativeintertiecosts.Thecostoftransmittingenergyfromaparticulargeneratingsourcetotheinterconnectedsystemisincludedinallcases.Selectionofnon-Susitnaplanswhichincorporatehydroelectricdevelopmentswasaccomplishedbytheapplicationofafive-stepmethodology(Figure1.2).Step1ofthisprocessessentiallyestablishedtheoverallobjectiveoftheexerciseastheselectionofanoptimumRailbeltgenerationplanwhichincorporatedthepro-posednon-Susitnahydroelectricdevelopments,forcomparisonwithotherplans.UnderStep2oftheselectionprocess,allfeasiblecandidatesiteswereidenti-fiedforinclusioninthesubsequentscreeningexercise.Atotalof91poten-tialsiteswereobtainedfrominventoriesofpotentialsitespublishedintheCOENationalHydropowerStudyandtheAPAreportIIHydroelectricAlternativesforAlaskaRailbeltil.Fromthese91sites,10wereselectedforfurtherstudyonthebasisofeconomicandenvironmentalsuperiorityafterafour-iterationCr~'Q~.ningprocess.2.5-SusitnaBasinInformationpresentedhereinontheclimatological,physicalandenvironmentalcharacteristicsoftheSusitnaRiverBasinhasbeenobtainedbothfrompreviousstudiesandthefieldprogramsandofficestudiesinitiatedduring1980underTasks3,4,5and7.(a)ClimatologyandHydrologyTheclirnateoftheSusitnaBasinupstreamfromTalkeetnaisgenerallycharacterizedbycold,drywintersandwarm,moderatelymoistsummers.Theupperbasinisdominatedbycontinentalclimaticconditionswhilethelower2-5 basinfallswithinazoneoftransitionbetweenmaritimeandcontinentalclimaticinfluences.TheSusitnaRiverusuallystartstofreezebylateOctober.Rivericeconditionssuchasthicknessandstrengthvaryaccordingtotheriverchannelshapeandslope,andmoreimportantly,withriverdischarge.Periodicmeasurementsoficethicknessatseverallocationsintheriverhavebeencarriedoutduringthewintersof1961through1972.IcebreakupintherivercommencesbylateAprilorearlyMayandicejamsoccasionallyoccuratriverconstrictions,resultinginrisesinwaterlevelofupto20feet.Seasonalvariationofflowsisextremeandrangesfromverylowvaluesinwinter(OctobertoApril)tohighsummervalues(MaytoSeptember).FortheSusitnaRiveratGoldCreektheaveragewinterandsummerflowsare2100and20,250cfsrespectively,i.e.a 1to10ratio.Ontheaverage,approximately88percentofthestreamflowrecordedatGoldCreekstationoccursduringthesummermonths.Athigherelevationsinthebasinthedistributionofflowsisconcentratedevenmoreinthesummermonths.FortheMaclarenRivernearPaxson(El4520feet)theaveragewinterandsummerflowsare144and2100cfsrespectively,i.e.a 1to15ratio.ThemostcommoncausesoffloodpeaksintheSusitnaBasinaresnowmeltoracombinationofsnowmeltandrainfalloveralargearea.AnnualmaximumpeakdischargesgenerallyoccurbetweenMayandOctoberwiththemajority,approximate1y60percent,occurringinJune.Someoftheannua1maximumfloodpeakshavealsooccurredinAugustorlaterandaretheresultofheavyrainsoverlargeareasaugmentedbysignificantsnowmeltfromhigherelevationsandglacialrunoff.(b)RegionalGeologyTheupperSusitnaBasinlieswithinwhatisgeologicallycalledtheTalkeetnaMountainsarea.Thisareaisgeologicallycomplexandhasahistoryofatleastthreeperiodsofmajortectonicdeformation.Theoldestrocks(250to300m.y.b.p.*)exposedintheregionarevolcanicflowsandlimestoneswhichareoverlainbysandstonesandshalesdatedapproximately150to200m.y.b.p.Atectoniceventapproximately135to180m.y.b.p.resultedintheintrusionoflargedioriteandgraniteplutons,whichcausedintensethermalmetamorphism.Thiswasfollowedbymarinedepositionofsiltsandclays.TheargillitesandphylliteswhichpredominateatDevilCanyonwereformedfromthesiltsandclaysduringfaultingandfoldingoftheTalkeetnaMountainsareaintheLateCretaceousperiod(65to100m.y.b.p.).Asaresultofthisfaultinganduplift,theeasternportionoftheareawaselevated,andtheoldestvolcanicsandsedimentswerethrustovertheyoungermetamorphicsandsediments.ThemajorareaofdeformationduringthisperiodofactivitywassoutheastofDevilCanyonandincludedthe~Jatanaarea.TheTalkeetnaThrustFault,awell-knowntectonicfeature,trendsnorthwestthroughthisregion.Thisfaultwasoneofthemajormechanismsofthisoverthrustingfromsoutheasttonorthwest.TheDevilCanyonareawasprobablydeformedandsubjectedtotectonicstressduringthesameperiod,bnomajordeformationsareevidentatthesite.*m.y.b.p.:millionyearsbeforepresent2-6 ThedioriteplutonthatformsthebedrockoftheWatanasitewasintrudedintosedimentsandvolcanicsabout65m.y.b.p.Theandesiteandbasaltowsnearthesitemayhavebeenformedimmediatelyafterthisplutonicintrusion,orafteraperiodoferosionandminordeposition.DuringtheTertiaryperiod(20to40m.y.b.p.)theareasurroundingthesiteswasagainupliftedbyasmuchas3,000feet.Sincethenwidespreaderosionhasremovedmuchoftheoldersedimentaryandvolcanicrocks.DuringthelastseveralmillionyearsatleasttwoalpineglaciationshavecarvedtheTalkeetnaMountainsintotheridges,peaks,andbroadglacialplateausseentoday.Postglacialuplifthasinduceddowncuttingofstreamsandrivers,resultinginthe500to700feetdeepV-shapedcanyonsthatareevidenttoday,particularlyattheVeeandDevilCanyondansites.Thiserosionisbelievedtobestilloccurringandvirtuallyallstreamsandriversintheregionareconsideredtobeactivelydowncutting.Thiscon-tinuingerosionhasremovedmuchoftheglacialdebrisathigherelevationsbutverylittlealluvialdepositionhasoccurred.Theresultinglandscapeconsistsofbarrenbedrockmountains,glacialtill-coveredplains,andex-posedbedrockcliffsincanyonsandalongstreams.Thearcticclimatehasretardeddevelopmentoftopsoi1.Furthergeologicmappingoftheprojectareaandgeotechnicalinvestigationoftheproposeddamsiteswasinitiatedunderthecurrentstudyin1980,andwillcontinuethroughearly1982.TalkeetnaMountainsregionofsouth-centralAlaskalieswithintheTalkeetnaTerrain.Thistermisthedesignationgiventotheimmediateregionofsouth-centralAlaskathatincludestheupperSusitnaRiverbasin.TheregionisboundedonthenorthbytheDenaliFault,andonthewestbyAlaskaPeninsulafeaturesthatmakeuptheCentralAlaskaRange.SouthoftheTalkeetnaMountains,theTalkeetnaTerrainisseparatedfromtheChachMountainsbytheCastleMountainFault.TheproposedSusitna~\In~nalectricProjectdamsitesarelocatedinthewesternhalfofthekeetnaTerrain.Theeasternhalfoftheregionincludestherelativelyinactive,ancientzoneofsedimentsundertheCopperRiver~asinandisboundedontheeastbytheTotschundasectionoftheDenaliFaultandthevolcanicWrangellMountains.SeismicAspectsRegionalearthquakeactivityintheprojectareaiscloselyrelatedtotheplatetectonicsofAlaska.ThePacificPlateisunderthrustingtheNorthPmericanPlateinthisregion.ThemajorearthquakesofAlaska,includingtheGoodFridayearthquakeof1964,haveprimarilyoccurredalongtheboundarybetweentheseplates.ThehistoricalseismicityinthevicinityofthedamsitesisassociatedwithcrustalearthquakeswithintheNorthPmericanPlateandtheshallowanddeepearthquakesgeneratedwithintheBenioffZone,whichunderliestheprojectarea.HistoricaldatarevealthatthemajorsourceofearthquakesinthesiteregionisinthedeepportionoftheBenioffZone,withdepthsrangingbetween24to36milesbelowthesurface.Severalmoderatesizeearthquakeshavebeenreportedatthesedepths.ThecrustalseismicitywithintheTalkeetnaTerrainisverylowbasedonhistoricalrecords.MostoftherecordedearthquakesintheareaarereportedtoberelatedtotheDenali-ToschundaFault,theCastleMountainFaultortheBenioffZone.2-7 (d)EnvironmentalAspectsNumerousstudiesoftheenvironmentalcharacteristicsoftheSusitnaRiverBasinhavebeenundertakeninthepast.Thecurrentstudieswereinitiatedinearly1980andareplannedtocontinueindefinitely.ThesestudiesconstitutethemostcomprehensiveanddetailedexaminationoftheSusitnaBasineverundertaken,andpossiblyofanycomparableresource.TheSusitnabasinisinhabitedbyresidentandanadromousfish.TheanadromousgroupincludesfivespeciesofPacificsalmon:sockeye(red);coho(silver);chinook(king);pink(humpback);andchun(dog)salmon.DollyVardenarealsopresentinthelowerSusitnaBasinwithbothresidentandanadromouspopulations.AnadrOllloussmeltareknowntorunuptheSusitnaRiverasfarastheDeshkaRiverabout40milesfromCookInlet.Theprojectareaisknowntosupportspeciesofcaribou,moose,bear,wolves,wolverineandDallsheep.FurbearersintheUpperSusitnaBasinincluderedfox,coyote,lynx,mink,pinemarten,riverotter,short-tailedweasel,leastweasel,muskratandbeaver.Directinnundation,constructionactivitiesandaccesscanbeexpectedtogenerallyhaveminimalimpactonthesespecies.Onehundredandfifteenspeciesofbirdswererecordedinthestudyareaduringthe1980fieldseason,themostabundantbeingScaupandCommonRed-poll.Tenactiveraptor/ravennestshavebeenrecordedandofthese,twoBaldEaglenestsandatleastfourGoldenEaglenestswouldbefloodedbytheproposedreservoirs,aswouldaboutthreecurrentlyinactiveraptor/ravennestsites.Preliminaryobservationsindicatealowpopulationofwaterbirdsonthelakesintheregion;however,TrunpeterSwansnestedonanunberoflakesbetweentheOshetnaandTyoneRivers.Floodingwoulddestroya 1argepercentageoftheripariancliffhabitatandforesthabitatsupriverofDevilCanyondam.Raptorsandravensusingthecliffswouldbeexpectedtofindalternatenestingsitesinthesurroundingmountains,buttheforestinhabitantsarerelativelycommonbreedersinforestsinadjacentregions.Lesseramountsoflowlandmeadowsandoffluviatileshorelinesandalluvia,eachimportanttoafewspecies,willalsobelost.Noneofthewaterbodiesthatappeartobeimportanttowaterfowlwillbeflooded,norwilltheimportantpreyspeciesoftheup-landtundraareasbeaffected.Impactsofothertypesofhabitataltera-tionwilldependonthetypeofalteration.Potentialimpactscanbelessenedthroughavoidanceofsensitiveareas.Thirteensmallmammalspecieswerefoundduring1980,andthepresenceofthreeotherswassuspected.Duringthefallsurvey,red-backedvolesandmaskedshrewswerethemostabundantspeciestrapped;andthese,plustheduskyshrew,appearedtobehabitatgeneralists,occupyingawiderangeofvegetationtypes.Meadowvolesandpygmyshrewswereleastabundantandthemostrestrictedintheirhabitatuse,theformeroccupyingonlymeadowsandthelatterforests.TheSusitnaRiverdrainspartsoftheAlaskaRangeonthenorthandpartsoftheTalkeetnaMountainsonthesouth.Manyareasalongtheeast-westportionoftheriver,betweentheconfluencesofPortageCreekandthe2-8 OshetnaRiver,aresteepandcoveredwithconifer,deciduousandmixedconifer,anddeciduousforests.Flatbenchesoccuratthetopsofthesebanksandusuallycontainlowshruborwoodlandconifercommunities.Lowmountainsrisefromthesebenchesandcontainsedge-grasstundraandmatandcushiontundra.The1980archaeologicalreconnaissanceintheSusitnaHydroelectricProjectarealocatedanddocumented40prehistoricsitesandonehistoricsite.Itisexpectedthatcontinuousreconnaissancesurveysin1981willlocateadditionalsites.SitesarealsodocumentedadjacenttothestudyareanearStephanLake,FogLakes,LakesSusitna,TyoneandLouise,andalongtheTyoneRiver.Determinationsofsignificanceofsiteswillbebasedontheintensivetestingdatacollectedduringthesummerof1981andnationalregistercriteriawhichdetermineeligibilityforthenationalregisterofhistoricplaces.Commercialfisheriesconstitutetheoldestcash-basedindustryofmajorimportancewithintheregion.Theindustryhaschangedsubstantiallyduringthepast20yearsandcontinuestobemodifiedasaresultofbothbiologicandeconomicstimuli.Thesalmonindustryhasalwaysbeenamajorcomponentoftheindustryintermsofvolumeandvalue.Since1955,thekingcrab,shrimp,andTannercrabfisherieshaveundergonemajordevelopnent,andhalibutlandingshaveincreasedsubstantiallyinrecentyears.Thetotalwholesalevalueofcommercialfishandshell-fishforthedomesticfisheryofAlaskain1979wasjustover$1.2billionincludingacatchof459millionpoundsofsalmonwithawholesalevalueofjustover$700million.ExistinglanduseintheSusitnaProjectareaischaracterizedbybroadex-pansesofopenwildernessareas.Thoseareaswheredevelopmenthasoc-curredoftenincludedsmallclustersofseveralcabinsorotherresidences.Therearealsomanysinglecabinsettlementsthroughoutthebasin.Thereareapproximately109structureswithin18milesoftheSusitnaRiverbetweenGoldCreekandtheTyoneRiver.Theseincludefourlodgesinvolvingsome21structures.AsignificantconcentrationofresidencecabinsorotherstructuresarefoundneartheOtterLakearea,PortageCreek,HighLake,GoldCreek,ChunilaCreek,StephanLake,FogLake,TsusenaLake,WatanaLake,ClarenceLake,andBigLake.-SusitnaBasinDevelopmentSelectionrnnnnr~hl~nciveseriesofengineeringandplanningstudieswerecarriedoutasaformulationofSusitnaBasindevelopmentplansandselectionoftheplan.TheselectionprocessusedisconsistentwiththegenericplanationandselectionmethodologydiscussedinSection1.Therecommended,theWatana/DevilCanyondamproject,iscomparedtoalternativemethodsof'QnQ~:'TingRailbeltenergyneedsincludingthermalandotherpotentialhydro-icdevelopmentsoutsidetheSusitnaBasinonthebasisoftechnical,~r.nnnrnic,environmentalandsocialaspects.outlinedinthedescriptionofthegenericplanformulationandselectionlogy(Section1.4)fivebasicstepsarerequired.Theseessentiallyistofdefiningtheobjectives,selectingcandidates,screening,formulationdevelopmentplansandfinally,adetailedevaluationoftheplans.2-9 Theobjectivesofthesestudiesareessentiallytwofold;thefirstistodeter-minetheoptimumSusitnaBasindevelopmentplanandthesecondtoundertakeapreliminaryassessmentofthefeasibilityoftheselectedplanbycomparisonwithalternativemethodsofgeneratingenergy.Throughoutthisplanningprocess,engineeringlayoutstudieswereconductedtorefinethecostestimatesforpowerorwaterstoragedevelopmentatseveraldamsiteswithinthebasin.Astheybecameavailable,thesedatawerefedintothescreeningandplanformulationandevaluationstudies.TheresultsofthesitescreeningexerciseindicatethattheSusitnaBasindevelopmentplanshouldincorporateacombinationofseveralmajordamsandpowerhouseslocatedatoneormoreofthefollowingsites:-Devi1Canyon-HighDevilCanyon-Watana-SusitnaIII-VeeInaddition,thefollowingtwositesaretobeconsideredascandidatesforsupplementaryupstreamflowregulation:-Maclaren-DenaliToestablishthelikelyoptimumcombinationofdams,acomputerscreeningmodelwasusedtodirectlyidentifythetypesofplansthataremosteconomic.ResultsoftheserunsindicatethattheDevilCanyon/WatanaortheHighDevilCanyon/Veecombinationsarethemosteconomic.Inadditiontothesetv.obasicdevelopmentplans,atunnelschemewasalsointroduced.Thisalternativepro-videspotentialenvironmentaladvantagesbyreplacingtheDevilCanyondambyalongpowertunnel.Afurtheralternativedevelopmentplaninvolvingthetwomosteconomicdamsites,HighDevilCanyonandWatana,wasalsoconsidered.ThemaincriterionusedintheinitialselectionofSusitnaBasindevelopmentplans,isthatofeconomics.EnvironmentalconsiderationsareincorpQratedintotheassessmentoftheplansfinallyselected.Theresultsofthefina:lscreen-ingprocessindicatethattheWatana/DevilCanyonandtheHighDevilCanyon/Veeplanswarrantfurther,moredetailedstudy.Inaddition,itwasdecidedtostudyfurtherthetunnelschemeandtheWatana/HighDevilCanyonplan.Fourbasinplansareconsidered.Plan1dealswiththeWatana/DevilCanyonsites,Plan2withtheHighDevilCanyon/Veesites,Plan3withtheWatanatunnelconcept,andPlan4withtheWatana/HighDevilCanyonsites.Inassess-ingtheseplans,areach-by-reachcomparisonwasmadeforthesectionoftheSusitnaRiverbetweenPortageCreekandtheTyoneRiver.TheWatana/DevilCanyonschemev.ouldcreatemorepotentialenvironmentalimpactsintheWatanaCreekarea.However,itwasjUdgedthatthiswasmorethancompensatedforbyavoidingtheevengreaterpotentialenvironmentalimpactsintheupperreachesoftheriver,whichwouldresultfromaHighDevilCanyon/Veedevelopment.2-10 Fromafisheries·perspective,bothschemeswouldhaveasimilareffectonthedownstreamanadromousfisheriesalthoughtheHighDevilCanyon/VeeschemewouldproduceaslightlygreaterimpactontheresidentfisheriesintheUpperSusitnaBasin.Exceptfortheincreasedlossofrivervalley,bird,andblackbearhabitat,theWatana/DevilCanyondevelopmentplanwasjudgedtobemoreenvironmentallyac-ceptablethantheHighDevilCanyon/Veeplan.AlthoughtheWatana/DevilCanyonplanisconsideredtobethemoreenvironmentallycompatibleUpperSusitnadevelopmentplan,theactualdegreeofacceptabilityisaquestionbeingaddressedaspartofongoingstudies.Thetwoplansinwerealsoevaluatedandcomparedintermsofenergycontribu-t.ioncriteria.TheWatana/DevilCanyonisassessedtobesuperiorduetoitshigherenergypotentialandthefactthatitdevelopsahigherproportionofthebasin1spotential.Intermsofsocialcriteria,asinthecaseofthedamersustunnelcomparison,theWatana/DevilCanyonplanisjudgedtohavealightadvantageovertheHighDevilCanyon/Veeplanbecauseofthehigherpotentialfordisplacingnonrenewableresources.TheoverallevaluationindicatesthattheWatana/DevilCanyonplansaregener-llysuperiorforalltheevaluationcriteriaconsidered.Thus,theWatana/evilCanyonplanisjudgedtobethebestSusitnaBasindevelopmentplan.2~7-SusitnaHydroelectricDevelopmenthestudiesdiscussedinthisreportconcludethat,onthebasisoftheanalysesodate,thefuturedevelopmentofRailbeltelectricpowergenerationsources.~houldincludeaSusitnaHydroelectricProject.However,furtherworkisrequiredtofullyestablishthetechnicalandeconomicfeasibilityofthe$usitnaprojectandtorefineitsdesign.selectedbasindevelopmentplaninvolvestheconstructionoftheWatanadamacrestelevationcurrentlyestimatedas2225feet,witha400MWpowerhouseeduledtocommenceoperationby1993.Thisdateistheearliestthataectpfthismagnitudecanbebroughton-line.Adelayinthisdatewouldtha.tadditionalthermalunitswouldhavetobebroughton1inetomeettheecteddemand,resultinginanincreaseinthecostofpowertotheconsumer.firststagewouldbefollowedbyexpansionofthepowerhousecapacitytoMWby1996andpossiblytheconstructionofare-regulationdamdownstreamallowdailypeakingoperations.Moredetailedenvironmentalstudiesareiredtofirmuptherequirementforthisre-regulationdam;itmaybeibletoincorporateitintheDevilCanyondamdiversionfacilities.ThestageinvolvestheconstructionoftheDevilCanyondamtoacrestationof1465feetwithaninstalledcapacityof400MWbytheyear2000.uldtheloadgrowthoccuratalowerratethanthecurrentmediumforecast,considerationshouldbegiventopostponingthecapacityexpansionproposedWatana,andtheconstructionoftheDevilCanyondamtotheyear2002,oriblyeven2005.Theselattertwodatescorrespondrespectivelytothelowastandtheextremelowforecastincorporatinganincreasedlevelofload2-11 managementandconservation.Foractualloadgrowthrateshigherthanthemediumloadforecasts,constructionoftheDevilCanyondamcouldbeadvancedto1998.Althoughithasbeendemonstratedthatthisdeve10pnentplanisextremelyeco-nomicforawiderangeofpossiblefutureenergygrowthrates,theactualsche-dulingforthevariousstagesshouldbecontinuouslyreassessedonperhapsafiveyearbasis.Itshouldalsobestressedthatthedamheightsandinstalledcapacitiesquotedabovearepreliminaryandsubjecttomodificationasthemoredetailedprojectoptimizationstudiesareconductedin1981.Thedamtypeselected fortheDevilCanyondamsitehasbeenrevisedfromtherockfi11alternativeassumedintheinitia1Basindeve10pnentstudies,toathindoub1ecurvatureconcretearchdam.Moredetailedengineeringstudiescarriedoutsubsequenttotheplanningstudiesdescribedhaveindicatedthisdc:mtypetobemoreappropriatetothesiteconditionsandslightlymorecosteffective.Atthisstageofthestudy,apreliminaryassessmentoftheconstructionsche-dulesfortheWatanaandDevilCanyondamshasbeenmade,mainlytoprovideareasonableestimateofon-linedatesforthegenerationplanningstudies.Moredetailedconstructionscheduleswillbedevelopedduringthe1981studies.Indeve10pingthesepreliminaryschedules,roughly70majorconstructionactivi-tieswereidentifiedandtheapplicablequantitiessuchasexcavation,borrowandconcretevolumesweredetermined.Constructiondurationswerethenestima-tedusinghistoricalrecordsasbackupandtheexpertiseofseniorscheduler-planners,estimatorsanddesignstaff.Acriticalpathlogicdiagrc:mwasdevel-opedfromthoseactivitiesandtheprojectdurationwasdetermined.Thecriticalornewcriticalactivitydurationswerefurtherreviewedandrefinedasneeded.Theseconstructionlogicdiagramsarecodedsothattheymaybeincorporatedintoacomputerizedsystemforthemoredetailedstudiestobeconductedduring1981.2.8-ConclusionsandRecommendations(a)ConclusionsAstandardmethodologyhasbeenadoptedtoguidetheSusitnaBasindevelop-mentselectionprocessdescribedinthisreport.Itincorporatesaseriesofscreeningstepsandconcludeswithplanformulationandevaluationpro-cedures.Boththescreeningandplanevaluationproceduresincorporatecriteriarelatingtotechnicalfeasibility,environmentalandsocioeconomi(aspects,andeconomicviability.TheeconomicanalysesarerequiredtoassisttheStateinallocatingfundsoptimallyandarethereforeconductedusingareal(i.e.,inflationad-justed)interestrateof3percentandacorrespondinggeneralinflationrateofzeropercent.Fuelcostsareassumedtoescalateatspecifiedamountsabovethegeneralinflationrate.AnalysesbasedontheforegoingassumptionshaveallowedcertainconclusionstobemadeforfutureRai1be1generationplanningpurposes.Previousstudiesoverthepast30yearshavethoroughlyinvestigatedthepotentialofthebasin,andthemostrecentstudiesconductedbytheCOE2-12 haveconcludedthattheWatana-DevilCanyondevelopnentplanisthepreferredoption.However,reviewofthesestudieshasindicatedthatacertainamountofrevisionisappropriate.Theserevisionsarenecessarybothtodevelopamoreuniformlevelofdetailforallthealternativesitesconsidered,andtoreassesstheearlierplanningdecisionsinthelightofcurrentloadprojections,whicharegenerallylowerthanthoseusedintheearlierstudies.Thecurrent(1980)RailbeltSystemannualenergyrequirementisestimatedtobe2790Gwhandthepeakdemand515MW.Nearfuturedernandscanbesatisfiedbytheexistinggeneratingsystem,thecommittedexpansionatBradleyLake(hydroelectric)andthecombinedcycle(gas~fired)plantatAnchorage.Thesewillmeetthedemanduntil1993providedanAnchorage-Fairbanksintertieofadequatecapacityisconstructed.Arangeoftechnicallyfeasibleoptionscapableofmeetingfutureenergyand.capacitydemandshavebeenidentifiedandincludethefollowing:-ThermalUnits·Coal-firedsteamgeneration:100,250,and500MWCombinedcyclegeneration:250MWGasturbinegeneration:75MW·Dieselgeneration:10MW-HydroelectricOptionsAlternativedevelopnentplansfortheSusitnaBasincapableofpro-vidingupto1200to1400MWcapacityandanaverageenergyyieldofapproximately6000Gwh.·TenadditionalpotentialhydroelectricdevelopnentslocatedoutsidetheSusitnaBasinandrangingfrom8to480MWincapacityand33to1925Gwhannualenergyyield.IndicationsarethattheutilitieswillbesubjecttotheprohibitionsoftheFuelUseActandthattheuseofnaturalgasinnewfacilitieswillberestrictedtopeakloadapplicationonly.TheSusitnaBasindevelopnentselectionstudiesindicatedthatthe1200MWWatana-DevilCanyondamschemeistheoptimumbasindevelopnentplanfromaneconomic,environmental,andsocialpointofview.Itinvolvesan880feethighfilldamatWatanawithanultimateinstalledcapacityof800MW,anda675feethighconcretearchdamatDevilCanyonwitha400MWpowerhouse.Thisprojectwilldevelopapproximately91percentofthetotalbasinpotential.Shouldonlyonedamsitebedevelopedinthebasin,thentheHighDevilCanyondam,whichdevelops53percentofthebasinpotential,providesthemosteconomicalenergy.Thisproject,however,isnotcompatiblewiththeWatana-DevilCanyondevelopnentplanasthesitewouldbeinundatedbytheDevilCanyondevelopnent.2-13 ComparisonoftheRai1be1tsystemgenerationscenarioincorporatingtheWatana-Devi1CanyonSusitnadevelopmentandtheall-thermaloptionrevealsthatthescenarioIIwithSusitnalliseconomicallysuperiorandreducesthetotalsystempresentworthcostby$2280million.Anoverallevaluationofthesetwoscenariosbasedoneconomic,environmental,andsocialcriteriaindicatesthattheIIwithSusitnallscenarioisthepreferredoption.TheIIwithSusitnallscenari0remainsthemosteconomicforawiderangeloadforecastandparameterssuchasinterestrate,fuelcostsandfuelescala-tionrates.Forrealinterestratesabove8percentorfuelescalationratesbelowzero,theallthermalgeneratingscenariobecomesmoreeconom-ic.However,itisnotlikelythatsuchhighinterestratesorlowfuelescalationrateswouldprevailduringtheforeseeablefuture.EconomiccomparisonsofthegeneratingscenariosIIwithSusitnallandthescenarioincorporatingalternativehydrooptionsindicatethatthepresentworthcostoftheIIwithSusitnallscenariois$1190millionless.Pre1imaryengineeringstudiesindicatethatthepreferreddamtypeatWatanaisarockfi11alternative,whileadoublecurvaturethinarchconcretedamisthemostappropriatetypefortheOevi1Canyonsite.(b)RecommendationsTherecommendationsoutlinedinthissectionpertaintothecontinuingstudiesunderTask6-DesignandDevelopment.Itisassumedthatthenecessaryhydrologic,seismic,geotechnical,environmental,andtranmissionsystemstudieswillalsocontinuetoprovidethenecessarysupportdataforcompletionoftheFeasibilityReport.ProjectplanningandengineeringstudiesshouldcontinueontheselectedSusitnaBasinWatana-Devi1Canyondevelopmentplan.Thesestudiesshouldencompassthefollowing:-AdditionaloptimizationstudiestodefineinmoredetailtheWatana-Devi1Canyondevelopmentplan.Thesestudiesshouldbeaimedatrefining:Damheights.Installedcapacities.AspartofthistaskconsiderationshouldalsobegiventolocatingthetailraceoftheDevilCanyonpowerhouseclosertoPortageCreekinordertomakeuseoftheadditionalheadestimatedtoamountto55feet.Reservoiroperatingrulecurves.Projectschedulingandstagingconcepts.Amoredetailedanalysisofthestagingconceptshouldbeundertaken.Thisshouldincludeareevaluationofthepowerhousestagesizesandtheconstructionschedules.Inaddition,anassessmentshouldbemadeofthetechnical,environmentalandeconomicfeasibilityofbringingtheDevilCanyondamandpowerhouseon-linebeforetheWatanadevelopment.2-14 ThismaybeanattractivealternativefromaschedulingpointofviewasitallowsSusitnapowertobebroughton-lineatanearlierdateduetotheshorterconstructionperiodassociatedwiththeDevilCanyondam.ThegeneralprocedureestablishedduringthisstudyforsiteselectionandplanformulationasoutinedinAppendixAshouldbeadheredtoinundertakingtheaboveoptimizationstudies.TheengineeringstudiesoutlinedinSubtasks6.07through6.31ofthepasshouldcontinueasoriginallyplannedinordertofinalizetheprojectgeneralarrangementsanddetails,andtofirmuptechnicalfeasibilityoftheproposeddevelopment.AsoutlinedintheoriginalTask6.37studyeffort,thegenerationscenarioplanningstudiesshouldberefinedoncemoredefinitiveprojectdataareobtainedfromthestudiesoutlinedaboveandtheRailbeltgenerationalternativesstudyiscompleted.Theobjectiveofthesestudiesshouldbetorefinetheassessmentoftheeconomic,environmental,andsocialfeasibilityoftheproposedSusitnaBasindevelopment.2-15 OFWORKScopeofWorkdiscussedinthissectionoftheDevelopmentSelectionReportludesthedevelopmentselectionstudiesandpreliminaryengineeringstudiesatrefiningthegeneralarrangementsoftheselectedWatanaandDevildamprojects.detailsoftheScopeofWorkmaybefoundintheAcres'POS(1,2).DevelopmentSelectionStudiesstudiesconstituteStage1oftheTask6designstudiesandincludethe1owing:ReviewofPreviousStudiesandReports(Subtask6.01)TheseactivitiesinvolveassemblingandreviewingallavailableengineeringdatapertainingtoSusitnaBasinhydropowerdevelopment.TheresultsofthisworkaresummarizedinSection4andare alsoreportedseparatelyinReference(3).InvestigateTunnelAlternatives(Subtask6.02)InthissubtaskconceptualengineeringdesignsofalongpowertunnelalternativetotheDevilCanyondamareproducedandevaluatedintermsofeconomicandenvironmentalimpact.ThisworkissummarizedinSection8andisreportedindetailinReference(4).EvaluateAlternativeSusitnaDevelopments(Subtask6.03)Thissubtaskincorporatesstudiesaimedatdevelopingengineering,costandenvironmentalimpactdataatallpotentialsiteswithintheSusitnaBasinandaseriesofscreeningandevaluationexercisestoproduceashortlistofpreferredSusitnaBasindevelopmentoptions.Thesestudiesincludethedevelopmentofengineeringlayoutsatseveralcandidatesiteswithinthebasininordertoimprovetheaccuracyofcapitalcostestimates.Computermodelsareusedtoscreenoutnon-economicdevelopmentplansandtoevaluatepowerandenergyyieldsofthemorepromisingdamschemes.ThisworkisdescribedinSection8.DetailedresultsarecontainedinAppendicesD,E,andF.WatanaandDevilCanyonStagedDevelopment(Subtask6.06)Asanextensiontotheengineeringlayoutworkdescribedabove,severaladditionallayoutstudieshavebeenundertakentoinvestigatethefeasibilityofstagingdamconstructionatthelargerdamsitessuchasWatanaandHighDevilCanyon.Considerationisalsogiventomethodsofstagingthemechanicalequipment.TheresultsofthesestudiesareincludedinSection8.3-1 (e)ThermalGeneratingResources(Subtask6.32)EconomicbenefitsofproposedSusitnaBasin~evelopmentsareevaluatedintermsoftheeconomicimpactontheentireRailbeltelectricalgeneratingsystem.ItisthereforenecessarytodevelopcostandperformancefiguresforalternativeenergygeneratingresourcesincludingthermalandotherpotentialhydrositeslocatedoutsidetheSusitnaBasin.Thesubtaskinvolvesstudiesundertakentodevelopperformanceandcostdataforarangeoffeasiblethermalgeneratingoptionsincludingcoalfiredsteam,gasturbine,combinedcycleanddieselplants.TheresultsofthissubtaskarereportedinSection6andAppendixB.(f)HydroelectY'icGeneratingSource(Subtask6.33)Thissubtaskinvolvesanextensivescreeningexerciseincorporatingeconomicandenvironmentalcriteria.TheaimofthisexerciseistoshortlistseveralpotentialhydroelectricdevelopmentslocatedoutsidetheSusitnaBasinwhichcouldsupplytherailbeltwithenergy.Conceptualsketchlayoutsareproducedfortheshortlistdevelopmentsinordertoestimatethecapitalcostsmoreaccurately.Computermodelsareusedtoindicatethepowerandenergyyields.TheresultofthisworkarereportedinSection6andAppendicesCandF.(g)EnvironmentalAnalysis(Subtask6.34)Thissubtaskincludestheenvironmentalstudiesnecessarytoscreenthepotentialhydroelectricdevelopmentsoutlinedin(f)aboveandtoprovidegeneralinformationonthepotentialenvironmentalimpactsassociatedwiththethermalgeneratingresources.TheresultsofthesestudiesareoutlinedinSections6and8andinAppendicesAandC.(h)LoadManagementandConservation(Subtask6.35)InordertothoroughlyassesstheeconomicsoftheproposedSusitnadevelopmentplanforawiderangeofprojectedloadforecastsitisnecessarytoassessthepotentialimpactofpossiblefuturelocalmanagementandconservationpractices.AbriefstudyisundertakentodeterminetheimpactofafeasibleloadmanagementandconservationscenarioandappropriateadjustmentsaremadetoenergyandloadforecastsforuseinthegenerationplanningstudiesdiscussedinSection5.(i)GenerationPlanning(Subtask6.36)ThissubtaskinvolvesthesystemwideeconomicanalysesundertakentodeterminetheeconomicbenefitsofvariousSusitnaBasindevelopmentplansandalternativeall-thermalandthermal-plus-other-hydrogeneratingscenarios.TheselattertwoscenariosarestudiedinordertoassesstheeconomicbenefitassociatedwithdevelopingtheSusitnaBasin.Acomputergenerationplanningmodelisusedtoundertaketheseanalyses.3-2 Section8andAppendixGoutlinetheresultsofthiswork.(j)DevelopmentSelectionReport(Subtask6.05)Thissubtaskdealswiththeproductionofthereport.ItalsoincludesasummaryoftheloadprojectionspreparedbyISERandthepowerprojectionsprovidedbyWCCinSection5.Additionalstudyworkisalsocarriedouttoformalizetheprojectdevelopmentselectionprocess,i.e.tointegratetheresultsofthestudiesoutlinedabovetoprovideacomprehensiveselectionprocessincorporatingeconomic,environmentalandotherconsiderations.3.2-ContinuedEngineeringStudiesAsthedevelopmentselectionstudieswerefinalizedworkcontinuedonengineeringdesignstudiesaimedatrefiningthegeneralarrangementsattheDevilCanyonandWatanasites.ThesestudiesinvolvetheproductionofalternativegeneralarrangementsincorporatingrockfillandconcretearchdamsatWatanaandseveralalternativeconcretearchdamsatDevilCanyon.Thesearrangementsarecostedandevaluatedtodeterminewhichisthemostappropriate.DesignworkiscarriedoutontheproposedthinarchdamatDevi1Canyontoensurethatsuchastructurecansafelywithstandtheanticipatedseismicloading.Extensiveuseismadeofcomputerstressanalysistechniquesinthedesignstudies.esestudiesarescopedinSubtasks6.04,6.07,and6.08andthere?ultsareummarizedinSection9andAppendixH.3-3 4 -PREVIOUSSTUDIESInthissectionofthereportasummaryispresentedofstudiesundertakenbytheWRPS(formerlytheUSBR),theCOEandothersovertheperiod1948through1979.4.1-EarlyStudiesofHydroelectricPotentialShortlyafterWorldWarIIendedtheUSBRconductedaninitialinvestigationofhydroelectricpotentialinAlaska,andissuedareportoftheresultsin1948.Respondingtoarecommendationmadein1949bythenineteenthAlaskaterritoriallegislaturethatAlaskabeincludedintheBureauofReclamationprogram,theSecretaryofInteriorprovidedfundstoupdatethe1948work.Theresultingreport,issuedin1952,recognizedthevasthydroelectricpotentialwithintheterritoryandplacedparticularemphasisonthestrategiclocationoftheSusitnaRiverbetweenAnchorageandFairbanksaswellasitsproximitytotheconnectingRai1be1t(SeeFigures1.1and4.1).Aseriesofstudieswascommissionedovertheyearstoidentifydamsitesandconductgeotechnicalinvestigations.By1961,theDepartmentoftheInteriorproposedauthorizationofatwodampowersysteminvolvingtheDevilCanyonandtheDenalisites(Figure4.1).Thedefinitive1961reportwassubsequentlyupdatedbytheAlaskaPowerAdministration(atthattimeanagencyoftheBureauofReclamation)in1974,atwhichtimethedesirabilityofproceedingwithhydroelectricdevelopmentwasreaffirmed.TheCOEwasalsoactiveinhydropowerinvestigationsinAlaskaduringthe1950·sand1960's,butfocuseditsattentiononamoreambitiousdevelopmentatRampartontheYukonRiver.ThisprojectwascapableofgeneratingfivetimesasmuchelectricenergyasSusitnaannually.ThesheersizeandthetechnologicalchallengesassociatedwithRampartcapturedtheimaginationofsupportersandeffectivelydivertedattentionfromtheSusitnaBasinformorethanadecade.TheRampartreportwasfinallyshelvedintheearly1970'sbecauseofstrongenvironmentalconcernsandtheuncertaintyofmarketingprospectsforsomuchenergy,particularlyinlightofabundantnaturalgaswhichhadbeendiscoveredanddevelopedinCookInlet.TheenergycrisisprecipitatedbytheOPECoilboycottin1973providedsomefurtherimpetusforseekingdevelopmentofrenewableresources.FederalfundingwasmadeavailablebothtocompletetheAlaskaPowerAdministration'supdatereportonSusitnain1974andtolaunchaprefeasibi1ityinvestigationbytheCOE.TheStateofAlaskaitselfcommissionedareassessmentoftheSusitnaProjectbytheHenryJ.KaiserCompanyin1974.AlthoughthegestationperiodforapossibleSusitnaProjecthasbeenlengthy,Federal,State,andprivateorganizationshavebeenvirtuallyunanimousovertheyearsinrecommendingthattheprojectproceed.Salientfeaturesofthevariousreportstodateareoutlinedinthefollowingsections.4-1 4.2-U.S.BureauofReclamation-1953Study(1)TheUSBR1952reporttotheCongressonAlaska'soverallhydroelectricpoten-tialwasfollowedshortlybythefirstmajorstudyoftheSusitnaBasinin1953.TendamsiteswereidentifiedabovetherailroadcrossingatGoldCreek(seealsoFigure4-1):-GoldCreek-Olson-DevilCanyon-DevilCreek-Watana-Vee-Maclaren-Denali-ButteCreek-Tyone(ontheTyoneRiver)FifteenmoresiteswereconsideredbelowGoldCreek.However,moreattentionhasbeenfocusedovertheyearsontheUpperSusitnaBasinwherethetopographyisbettersuitedtodamconstructionandwherelessimpactonanadromousfisher-iesisexpected.FieldreconnaissanceeliminatedhalftheoriginalUpperBasinlistandfurtherUSBRconsiderationcenteredonOlson,DevilCanyon,Watana,VeeandDenali.AlloftheUSBRstudiessince1953haveregardedthesesitesasthemostappropriateforfurtherinvestigation.4.3-U.S.BureauofReclamation-1961Study(2)In1961amoredetailedfeasibilitystudyresultedinarecommendedfivestagedevelopmentplantomatchtheloadgrowthcurveasitwasthenprojected.DevilCanyonwastobethefirstdevelopment--a635feethigharchdamwithaninstalledcapacityofabout220MW.ThereservoirformedbytheDevilCanyondamalonewouldnotstoreenoughwatertopermithighercapacitiestobeeconom-icallyinstalledsincelongperiodsofrelativelylowflowoccurinthewintermonths.ThesecondstagewouldhaveincreasedstoragecapacitybyaddinganearthfilldamatDenaliintheupperreachesofthebasin.SubsequentstagesinvolvedaddinggeneratingcapacitytotheDevilCanyondam.GeotechnicalinvestigationsatDevilCanyonweremorethoroughthanatDenali.AtDenali,testpitsweredug,butnodrillingoccurred.4.4-AlaskaPowerAdministration-1974(3)LittlechangefromthebasicUSBR-1961fivestageconceptappearedinthe1974reportbytheAlaskaPowerAdministration.Thislatereffortofferedamoresophisticateddesign,providednewcostandscheduleestimates,andaddressedmarketing,economics,andenvironmentalconsiderations.4.5-KaiserProposalforDevelopment(4)TheKaiserstudy,commissionedbytheOfficeoftheGovernorin1974,proposedthattheinitialSusitnadevelopmentconsistofasingledamknownasHighDevilCanyon(SeeFigure4.1).Nofieldinvestigationsweremadetoconfirmthetech-nicalfeasibilityoftheHighDevilCanyonlocationbecausethefundinglevelwasinsufficientforsuchefforts.Visualobservationssuggestedthesite4-2 wasprobablyfavorable.TheUSBRhadalwaysbeenuneasyaboutfoundationcondi-tionsatDenali,buthadtorelyupontheDenalireservoirtoprovidestorageduringlongperiodsoflowflow.Kaiserchosetoavoidtheperceiveduncertain-tyatDenalibyproposingtobuildarockfilldamatHighDevilCanyonwhich,at810feet,wouldcreatealargeenoughreservoirtoovercomethestorageproblem.thoughtheselectedsitesweredifferent,theCOEreachedasimilarconclusionwhenitlaterchosethehighdarnatWatanaasthefirsttobeconstructed.developmentssuggestedbyKaiserincludedadownstreamdamatthesonteandanupstreamdarnatSusitnaIII(seeFigure4.1).Theinformationopedfortheseadditionaldamswasconfinedtoestimatingenergypotential.intheCOEstudy,futuredevelopmentofDenaliremainedapossibilityifionconditionswerefoundtobeadequateandifthevalueofadditionalrmenergyprovidedeconomicjustificationatsomelaterdate.Kaiserdidnotregardthedevelopmentofanenergyconsumptivealuminumplantassarytoeconomicallyjustifyitsproposedproject.4.6-U.S.ArmyCorpsofEngineers-1975and1979Studies(5,6)mostcomprehensivestudyoftheUpperSusitnaBasintodatewascompletedin975bytheCOE.Atotalof23alternativedevelopmentswereanalyzed,includ-ngthoseproposedbytheUSBRaswellasconsiderationofcoalastheprimarysourceforRailbeltelectricalneeds.TheCOEagreedthatanarchdamatCanyonwasappropriate,butfoundthatahighdamattheWatanasitewouldalargeenoughreservoirforseasonalstorageandwouldpermitcontinuedgenerationduringlowflowperiods.COErecommendedanearthfilldamatWatanawithaheightof810feet.Inlongerterm,developmentoftheDenalisiteremainedapossibilitywhich,if~nlnct·~ucted,wouldincreasetheamountoffirmenergyavailable,eveninveryyears.Anad-hoctaskforcewascreatedbyGovernorJayHammonduponcompletionofthe1975COEStudy.ThistaskforcerecommendedendorsementoftheCOErequestforgressionalauthorization,butpointedoutthatextensivefurtherstudies,particularlythosedealingwithenvironmentalandsocioeconomicquestions,werenecessarybeforeanyconstructiondecisioncouldbemade.theFederallevel,concernwasexpressedattheOfficeofManagementandBUdgetregardingtheadequacyofgeotechnicaldataattheWatanasiteaswellasvalidityoftheeconomics.TheapparentambitiousnessofthescheduleandfeasibilityofathinarchdarnatDevilCanyonwerealsoquestioned.Fur-investigationswerefundedandtheCOEproducedanupdatedreportin1979.ilCanyonandWatanawerereaffirmedasappropriatesites,butalternativetypeswereinvestigated.Aconcretegravitydamwasanalyzedasanalterna-iveforthethinarchdamatDevilCanyonandtheWatanadarnwaschangedfromearthfilltorockfill.Subsequentcostandscheduleestimatesstillindicatedeconomicjustificationfortheproject.4-3 DAMSITES PROPOSED BY OTHERS FIGURE 4.1 IIIR I """""f oJ\.\ J <... l '"'\, I ~ '-"""\."-~\ \ \ \ ,.,J J-'/. ~J-. \ 1 I I'""\.1 \--;/ '"\ ) /,,------/ ./__1_J ~...,__v LEGEND TYONE·&DAMSITE TALKEETNA RIVER=---- Qf.Yl.I....CANyON HIGH .Q..C..f '\..\.,.......'-_I'"\........"""-"" GOLp CREEK \1, '\.. '", ~ \ (, '/ ( "\ ) ~~4. ~~":> #,~~~ ...(;ot. ~o~ ...'t>oc, ~ 5 0 5 15 ~I I I SCALE IN MILES LISTOFREFERENCES(1)(2)(3)(4)(5)(6)U.S.DepartmentoftheInterior,BureauofReclamation(AlaskaDistrict),DistrictManager'sReconnaissanceReportofAugust,1952onSusitnaRiverBasin:AReportonthePotentialDevelopmentofWaterResourcesintheSusitnaRiverBasinofAlaska,1952.U.S.DepartmentoftheInterior,BureauofReclamation(AlaskaDistrict),DevilCanyonProject,Alaska:ReportoftheCommissionerofReclamationandSupportingReports,1960.AlaskaPowerAdministration,DevilCanyonStatusReport,Juneau,Alaska,May,1974.H.J.Kaiser&Company,ReassessmentReportonUpperSusitnaRiverHydroelectricDevelopmentfortheStateofAlaska,September,1974.U.S.DepartmentoftheArmy,CorpsofEngineers(AlaskaDistrict),HydroelectricPowerandRelatedPurposes:SouthcentralRailbeltArea,Alaska,UpperSusitnaRiverBasin-InterimFeasibilityReport,Anchorage,Alaska,1975.U.S.DepartmentoftheArmy,CorpsofEngineers(AlaskaDistrict),HydroelectricPowerandRelatedPurposes:SouthcentralRailbeltArea,Alaska,UpperSusitnaRiverBasin-SupplementaryFeasibilityReport,Anchorage,Alaska,1979.4-5 5 -RAILBELTLOADFORECASTS5.1-IntroductionThefeasibilityofamajorhydroelectricprojectdependsinpartupontheextentwhichtheavailablecapacityandenergyareconsistentwiththeneedsofthemarkettobeservedbythetimetheprojectcomesonline.Attemptingtofore-castfutureenergydemandisadifficultprocessatbest;itisthereforeparti-cularlyimportantthatthisexercisebeaccomplishedinanobjectivemanner.ForthisreasonAPAandtheStateofAlaskajointlyawardedaseparatecontracttoISERtoprepareappropriateprojectionsfortheAlaskaRailbeltregion.Section5presentsareviewoftheeconomicscenariosuponwhichtheISERfore-castswerebasedandadiscussionoftheforecastsdevelopedforuseingener-ationplanningstudies.5.2-ElectricityDemandProfilesThissectionreviewsthehistoricalgrowthofelectricityconsumptionintheRailbeltandcomparesittothenationaltrend.Railbeltelectricityconsump-tionisthendisaggregatedbyregionsandbyend-usesectorstoclarifypastusagepatterns.(a)HistoricalTrendsBetween1940and1978,electricitysalesintheRailbeltgrewatanaverageannualrateof15.2percent.Thisgrowthwasroughlytwicethatforthenationasawhole.Table5.1showsU.S.andAlaskanannualgrowthratesfordifferentperiodsbetween1940and1978.ThehistoricalgrowthofRailbeltutilitysalesfrom1965isillustratedinFigure5.1.AlthoughtheRailbeltgrowthratesconsistentlyexceededthenationalaver-age,thegaphasbeennarrowinginlateryearsduetothegradualmaturingoftheAlaskaneconomy.GrowthintheRailbelthasexceededthenationalaveragefortworeasons:populationgrowthintheRailbelthasbeenhigherthanthenationalrate,andtheproportionofAlaskanhouseholdsservedbyelectricutilitieswaslowerthantheU.S.averagesothatsomegrowthinthenumberofcustomersoccurredindependentlyofpopulationgrowth.Table5.2comparesU.S.andAlaskangrowthratesintheresidentialandcommer-cialsectors.(b)RegionalDemandElectricitydemandintheRailbelt,disaggregatedbyregions,isshowninTable5.3.Duringtheperiodfrom1965to1978,GreaterAnchorageaccountedforabout75percentofRailbeltelectricityconsumptionfollowedbyGreaterFairbankswith24percentandGlennallen-Valdezwith1percent.Thepatternofregionalsharingduringthisperiodhasbeenquitestableandnodiscernibletrendinregionalshifthasemerged.ThisismainlyaresultoftheuniformrateofeconomicdevelopmentintheAlaskanRailbelt.5-1 (c)End-UseConsumptionRailbeltelectricityconsumptionbymajorend-usesectorisshowninTaol5.4.Intheresidentialsector,electricityconsumptionislargelyattriutedtospaceheating;utilitiessuchasrefrigerators,waterheaters,lightsandcookingrangesranknextinorderofusage.Inthecommer-cial-industrial-governmentsector,end-useconsumptionislessclearbecauseofalackofdata;however,itisreasonabletoassumethatelec-tricityisusedmainlyforlighting,spaceheating,coolingandwaterheating.Consumptioninthemiscellaneoussectorisattributedmainlytostreetlightingandusageinsecondhomes.Thedistributionofelectricityconsumptionintheseend-usesectorshasbeenfairlystable.By1978,thecommercial-industrial-governmentandresidentialsectorsaccountedfor52percentand47percentrespectively.Incontrast,the1978nationwideshareswere65percentand34percentrespectively(l).5.3-ISERElectricityConsumptionForecastsAsoutlinedinSection3,theelectricityconsumptionforecastswereundertakenbyISER(l).ThissectionbrieflydiscussesthemethodologyusedbyISERtoestimateelectricenergysalesfortheRailbelt,andsummarizestheresultsobtained.(a)MethodologyTheISERelectricitydemandforecastingmodelconceptualizedincomputerlogicthelinkagebetweeneconomicgrowthscenariosandelectricitycon-sumption.TheoutputfromthemodelisintheformofprojectedvaluesofelectricityconsumptionforeachofthethreegeographicalareasoftheRailbelt(GreaterAnchorage,GreaterFairbanksandGlennallen-Valdez)andisclassifiedbyfinaluse(i.e.,heating,washing,cooling,etc.)andcon-sumingsector(commercial,residential,etc).Themodelproducesoutputonafive-yeartimebasisfrom1985to2010,inclusive.TheISERmodelconsistsofseveralsubmodelslinkedbykeyvariablesanddrivenbypolicyandtechnicalassumptionsandstateandnationaltrends.Thesesubmodelsaregroupedintofoureconomicmodelswhichforecastfuturelevelsofeconomicactivityandfourelectricityconsumptionmodelswhichforecasttheassociatedelectricityrequirementsbyconsumingsectors.Fortwooftheconsumingsectorsitwasnotpossibletosetupcomputermodelsandsimplifyingassumptionsweremade.Themodelsandassumptionsaredescribedbelow.(i)EconomicSubmodelsTheMAPEconometricModelMAPisaneconometricmodelbasedonforecastedorassumedlevelsofnationaleconomictrends,Stategovernmentactivity,anddevelopmentsintheAlaskaresourcesector.Theseeconomicindi-catorsaretranslatedintoforecastedlevelsofstatewidepopula-tionbyageandsex,employmentbyindustrialsector,andincome.5-2 -TheHouseholdFormationModelThehouseholdformationmodelgroupsindividualsintohouseholdunitsonthebasisofnationalandstatedemographictrends.Theoutputistheforecastnumberofhouseholdheadsbyageandsex,whichisinturnaninputtothehousingstockandelectricityconsumptionmodels.-RegionalAllocationModelThismodeldisaggregatesMAp·sprojectionsofpopulationandemploymentintoregionsoftheRailbelt.Themodelusesecono-metrictechniquestostructureregionalsharesofstatepopula-tion,thesupportsector,andgovernmentemployment.-HousingStockModelThehousingstockmodelutilizestheoutputfromthehouseholdformationmodel,theregionalpopulationinformationfromtheregionalallocationmodel,andtheresultsofanindependentsurveyonhousingchoice.Theseoutputsarecombinedtoproducethenumberofhousingunitsbytype(e.g.singlefamily,duplex,multifamily,etc.)andbyregionforeachoftheforecastyears.(ii)ElectricityConsumptionSUbmodelsThesesubmodelsarestructuredtodetermineelectricityrequirementsforvariousdemandcomponents:-ResidentialNon-spaceHeatingElectricityRequirementsThismodelestimateselectricityrequirementsforhouseholdappliancesutilizingthefollowinginformation:·numberofhouseholdsappliancesaturationrate·fuelmodesplit·averageannualconsumptionofappliance·averagehouseholdsizeResidentialnon-spaceheatingelectricityrequirementsareobtainedbysummingtheelectricityrequirementsofallappli-ances.ResidentialSpaceHeatingThismodelestimatesspaceheatingelectricityrequirementsforfourtypesofdwellingunits:singlefamily,duplex,multi-family,andmobilehome.Thespaceheatingelectricityrequire-mentforeachtypeofdwellingunitiscalculatedastheproductofthenumberofdwellingunits,fuelmodesplitandspecifiedaveragelevelsof consumption.5-3 -Commercial-Industrial-GovernmentTotalelectricityrequirementsforthecommercial-industrial-governmentsectoraredefinedastheproductofnon-agriculturalwageandsalaryemploymentandaverageelectricityconsumptionperemployee.Electricityconsumptionperemployeeisafunctionoftimeandapplicationofconservationstandards.Thisimpliesthatnewelectricityusersinthissectorwillhavedifferentelectricityrequirementsthanpreviouscustomers.-MiscellaneousThismodelestimatestworemalnlngsectorsofelectricitycon-sumption:i.e.streetlightingandrecreationalhomes.(iii)ConsumptionSectorsNotModeledElectricityrequirementswerenotmodeledfortwosectorsofdemand:-MilitaryFormanyreasons,includingalackofhistoricaldata,nomodelisincludedtocorrelatemilitaryelectricityconsumptionwithcausalfactors.Hence,futureelectricityrequirementsforthemilitaryareassumedtobethesameasthecurrentlevel.Self-SuppliedIndustrialNomodelisincludedtoprojectfutureself-generatedelectricityforindustry.ExistingusersareidentifiedandcurrentelectricityconsumptiondeterminedforAPAsources.Newusersandfutureconsumptionlevelsareidentifiedfromeconomicscenarios.(b)AssumptionsTomakethesemodelsoperational,anumberofadditionalassumptionsareincorporated:TheelectricitymarketispresentlyinastateofrelativeequilibriumexceptforFairbankswhereashiftawayfromelectricspaceheatingisunderway.Thisequilibriumisexpectedtoremainineffectthroughouttheforecastperiodbecauseofrelativelyconstantfuelpriceratios.Thepriceofenergyrelativetoothergoodsandserviceswillcontinuetorise.Risingrealincomeswillacttoincreasethedemandforelectricity.Federalpolicieswillbeeffectiveintheareaofapplianceenergycon-servation,butwillhaveamuchsmallerimpactonbuildingstockthermalefficiencies.5-4 NoStateconservationpoliciesdirectedexclusivelytowardelectricitywillbeimplemented.NosignificantStatepoliciesdesignedtoalterthepriceoravailabil-ityofalternativefuelswillbeimplemented.Nonewelectricitytechnologieswillbeintroduced.Intermsofresidentialappliances:Saturationrateswillfollownationaltrends;Forsomeappliances,reducedhouseholdsizewillacttoreduceaverageelectricityrequirements;Consumptionisafunctionoftheappliancescrappingrateastheaverageageaffectsefficiency;UnspecifiedapplianceconsumptionwillincreasetoaccommodatethePossibilityofnewdomesticelectricityapplications.Intermsofresidentialspaceheating:Aslighttrendtowardsinglefamilyhomesisprojected;Averagehousingunitsizewillcontinuetogrow;Naturalgasavailabilitywillnotsignificantlyincrease;Spaceheatingalternativessuchasoil,woodorcoalwillnotgreatlyaffectaggregatespaceheatingdemand;Nosignificantincreaseinthenumberofheatpumpswilloccur.Intermsofcommercial-industrial-governmentuse:Employmentwillgrowmorerapidlythanthepopulation;Nomajorenergyconservationmeasuresareanticipated;Thedistributionofelectricityend-useswillnotshiftsignificantly.Miscellaneousutilitysales(streetlightingandsecondhomeuse)willgrowatratesconsistentwithpredictedtotalutilitysales.(c)ForecastingUncertaintyToadequatelyaddresstheuncertaintyassociatedwiththepredictionoffuturedemands,anumberofdifferenteconomicgrowthscenarioswereconsidered.Thesewereformulatedbyalternativelycombininghigh,moder-ateandlowgrowthratesintheareaofspecialprojectsandindustrywithStategovernmentfiscalpoliciesaimedatstimulatingeitherhigh,moderateorlowgrowth.ThisresultedinatotalofninepotentialgrowthscenariosfortheState.Inadditiontothesescenarios,ISERalsoconsideredthepotentialimpactofapricereducedshifttowardsincreasedelectricitydemand.Asoutlinedbelow,ashortlistofsixfuturescenarioswasselected.Theseconcentratedaroundthemid-rangeor"mostlikely"esti-mateandtheupperandlowerextremes.5-5 (d)ForecastResults(i)BaseCaseTheISERforecastwhichincorporatesthecombinationofmoderate.economicgrowthandmoderategovernmentexpenditureisconsideredtobethe"mostlikely"loadforecast.Thishasbeenidentifiedforthepurposeofthisstudyasthe"BaseCaseForecast".TheresultsofthisforecastarepresentedinTable5.5andindicatethatutilitysalesfortheRailbeltwillgrowfromthe1980levelof2390GWhto7952GWhin2010,representinganaverageannualgrowthrateof4.09percent.Overtheperiodoftheforecast,thehighestgrowthrateoccursfrom1990to2000at4.76percent,followedbyadeclineto3.33percentduringthe2000to2UI0period.(ii)RangeofForecastsInadditiontothebasecase,theISERresultsincorporateahigherandlowerrateofeconomicgrowthcoupledwithmoderategovernmentexpenditure,andtheyalsoincorporatethecasewhereashifttoelectricitytakesplace.Theseforecastsdonotprovideacompleteenvelopeofpotentialgrowthscenariosbecausetheimpactsofhighindustrialgrowth/highgovernmentexpenditureandlowindustrialgrowth/lowgovernmentexpenditureonelectricitydemandhavenotbeenincluded.Estimatesoftheseimpactshavebeencomputedbythemethodofproportionalityasapproximationstothemodelruns.AsummaryofaggregateRailbeltelectricitygrowthfortherangeofscenariosispresentedinTable5.6andinFigure5.2.Themediumgrowthrateof4.1percentisshowntobeboundedbylowerandupperlimitsof2.8percentand6.1percentrespectively.Incomparison,historicalelectricitydemandintheRailbelthasincreasedby11percent.5.4-PastProjectionsofRailbeltElectricityDemandAnumberofelectricityprojectionshavebeendevelopedinthepast.Thedis-cussionhereisconfinedtoworkconductedsince1975inordertocompareISER'sforecastswithpreviousworkandtorationalizeanydifferencesthatoccur.Forecastsofelectricpowerrequirementsdevelopedsince1975(excludingISER'slatestforecast)aresummarizedinTable5.7.Acursoryexaminationindicatesthatdifferenceswhichoccurintheearlyyearsprogressivelyincreasewithintheforecastperiod.Theperformanceoftheseforecastscanbeascertainedbycomparingthemto1980utilitysales.Table5.8snowsthepercenterrorintheforecastedgrowthrateto1980.Ascanbeseen,alloftheforecastssignifi-cantlyoverestimated1980consumption.TheseforecastsarealsosignificantlydifferentfromthosedevelopedrecentlybyISER;thedifferencesaremainlyattributedtoassumptionsconcerningeconomicgrowthandelectricityconsumptionrates.Althoughtheeconomicgrowthassumptionsincorporatedinpreviousstudieshavevariedwidely,theyhavebeengenerallymoreoptimisticwithrespecttothetype,sizeandtimingofprojectsandothereconomicevents.ThishasconsequentlyresultedinhigherprojectionsofeconomicactivitycomparedtotherecentISERstudy.5-6 ElectricityconsumptionratesintheISERstudiesaregeneral,lylowerthanthoseinpreviousstudies.ThisisessentiallybecauseISERhasbeenthefirsttoincorporateestimatesofappliancesaturationrates,end-usepatternsandcon-servationmeasures.5.5-UemandForecasts(a)ApproachTheoverallapproachtoderivationofthepeakdemandforecastsfortheRailbeltRegionwastoexaminetheavailablehistoricaldatawithregardtothegenerationofelectricalenergyandtoapplytheobservedgenerationpatternstoexistingsalesforecasts.InformationroutinelysuppliedbytheRailbeltutilitiestotheFederalEnergyRegulatoryCommissionwasutilizedtodeterminetheseloadpatterns.(b)LoadPatternsTheanalysisofloadpatternsemphasizedtheidentificationofaveragepat-ternsoverthe10-yearperiodfrom1970to1979anddidnotconsidertrendsorchangesinthepatternswithtime.Generally,theuseofaveragevalueswaspreferredasitreducedtheimpactofyearlyvariationsduetovariableweatherconditionsandoutages.Inanyevent,itwasnotpossibletodetectanypatternsintheavailabledata.TheaveragehourlydistributionofgenerationforthefirstweeksofApril,AugustandDecemberwasusedtodeterminethetypicalaverageloadpatternforthevariousutilities.Asaresultoftherelativelylimiteddatabase,thecalculatedloaddurationcurvewouldbeexpectedtoshowlessvariationthanonecomputedfromamorecompleteaatabaseresultinginanoverestimationoftheloadfactor.Inaddition,hourlydataalsotendtoaverageoutactualpeakdemandsoccurringwithinatimeintervaloflessthanonehour.Thiscouldalsoleadtooverestimationoftheloadfactor.Itis,however,believedthattheaccuracyachievedisadequateforthesestudies,particularlyinlightoftherelativelymuchgreateruncertaintiesassociatedwiththeloadforecasts.(c)SalesAllocationAlthoughtheaboveloaddataareavailablebyutility,thekWhsalesfore-castsarebasedonserviceareaalone.ThekWhsalesdatawereallocatedtotheindividualutilitiesutilizingapredictedmixofconsumercate-goriesintheareaandthecurrentmixofsalesbyconsumercategoryfortheutilitiesservingthearea.(d)PeakLoadsThetwodatasetswerecombinedtodeterminecompositepeakloadsfortheRailbeltarea.5-7 Thefirststepinvolvedanadjustmenttotheallocatedsalestoreflectlossesandenergyunaccountedfor.Theadjustmentwasmadebyincreasingtheenergyallocatedtoeachutilitybyafactorcomputedfromhistoricalsalesandgenerationlevels.Thisresultedinagrossenergygenerationforeachutility.Thefactorsdeterminedforthemonthlydistributionoftotalannualgenera-tionwerethenusedtodistributethegrossgenerationforeachyear.TheresultinghourlyloadsforeachutilitywereadaedtogethertoobtainthetotalRailbeltsystemloadpatternforeachforecastyear.Table5.9summarizesthetotalenergygenerationandthepeakloadsforeachofthelow,medium,andhighISERsalesforecasts,assumingmoderategovernmentexpenditure.Theloadfactorscomputedinthisstudyaveragesevenpercentagepointshigherthantheaverageloadfactorsobservedinthefourutilitiesoverthe10-yearperiod.5.6-PotentialforLoadManagementandEnergyConservationUtilitiesnationwidearecurrentlypayingincreasingattentiontotheimplemen-tationofloadmanagementandconservationmeasuresinanattempttoreduceorshiftpeakloadandtoreduceenergydemand.Loadmanagementisdefinedasthe"shifting"andcorrespondingreductionofpeakdemandsandthealterationofdailyloadshapesbymeansofappropriatemeasures.Althoughsomeloadmanage-menttechniquescanresultinaslightincreaseindailyenergydemand,theobjectiveisessentiallytoaccomplishareductionofpeakdemandwithnosigni-ficantdifferenceintotalenergydemand.Loadmanagementmaygenerallybeachievedbyoneoftwomethods:directcontrol,inwhichtheutilitycontrolstheend-usedevices;orindirectcontrol,inwhichpriceincentivesareusedtomotivateloadshiftingbytheconsumer.Conservationisdefinedasanetreduc-tioninenergydemandbymeansofappropriatemeasures,withacorrespondingreductioninpeakdemand.Thepotentialbenefitsofpowerdemandcontrolandreductionmeasuresrequirecarefulevaluationbeforeimplementationonamajorscale.AconsiderableamountofresearchanddevelopmentworkhasbeenundertakenintheLower48todevelopmethodsandcoststrategies,andtoassessthepotentialimpactofsuchstrategiesondemand.Asaresultofthiswork,loadmanagementandenergycon-servationconceptshaveeitherbeenimplementedorarebeingplannedbymanyutilities.Theanticipatedeffectsonthegrowthoffuturepeakloadandenergyconsumptionintheutilitysystemshavebeenincludedintheirforecasts.Cur-rentlyinAlaska,oneutility,AnchorageMunicipalLightandPower,hasinsti-tutedanexperimentaltime-of-dayrateforelectricity.Althoughconservationisessentiallyaccomplishedbyareductionindemand,itmayalsoberegardedasameansofdivertingavailableenergytootheruses,orcreatinga "new"sourceofenergy.ArecentstudybytheAlaskaCenterforPolicyStudies(2)indicatedthatconservationwasthemosteconomicallyattrac-tivesourceofnewenergyavailabletotheRailbeltarea.ThisconclusionwasbasedonevidencefromexistingweatherizationprogramsandprojectionsfromtheAlaskaFederationforCommunitySelfRelianceinFairbanks.However,thetotalamountofenergythatcanbemadeavailablebysuchmeansisrelativelysmallcomparedtothetotalKailbeltsystemenergydemanduptotheyear2010.5-8 TheISERforecastsincorporatedtheimpactsofcertainenergyconservationmeasures,butdidnotincludeanyloadmanagement.Inthisstudy,opportunitiesforimplementationofadditionalprogramsofintensifiedconservationandloadmanagementmeasuresareconsideredinthegenerationplanningstudies.Thesearediscussedinmoredetailinthefollowingsection.5.7-LoadForecastsUsedforGenerationPlanningStudiesThissectionoutlinestheadjustmentsthatweremadetoproducethetotalRail-beltsystemelectricityforecaststobeusedinthegenerationplanningstudiesdescribedinSection8.(a)AdjustedISERForecastsThreeISERenergyforecastswereconsideredingenerationplanningstudies(seeTable5.6).Theseincludethebasecase(MES-GM)ormediumforecast,alowandahighforecast.ThelowforecastisthatcorrespondingtotheloweconomicgrowthasproposedbyISERwithanadjustmentforlowgovern-mentexpenditure(LES-GL).ThehighforecastcorrespondstotheISERhigheconomicgrowthscenariowithanadjustmentforhighgovernmentexpenditure(HES-GH).TheelectricityforecastssummarizedinTable5.9representtotalutilitygenerationandincludeprojectionsforself-suppliedindustrialandmili-tarygenerationsectors.Includedintheseforecastsaretransmissionanddistributionlossesintherangeof9to13percentdependinguponthegenerationscenarioassumed.Theseforecasts,rangingfrom2.71to4.76percentaverageannualgrowth,wereadjustedforuseingenerationplanningstudies.Theself-suppliedindustrialenergyprimarilyinvolvesdrillingandoff-shoreoperationsandotheractivitieswhicharenotlikelytobeconnectedintotheRailbeltsupplysystem.Thiscomponent,whichvariesdependingupongenerationscenario,wasthereforeomittedfromtheforecastsusedforplanningpurposes.Themilitaryislikelytocontinuepurchasingenergyfromthegeneralmar-ketaslongasitremainseconomic.However,muchoftheirgeneratingcapacityistiedtodistrictheatingsystemswhichwouldpresumablycontin-ueoperation.Forstudypurposes,itwasthereforeassumedthat30percentoftheestimatedmilitarygenerationwouldbesuppliedfromthegridsystem.Theadjustmentsmadetopowerandenergyforecastsforuseinself-suppliedindustrialandmilitarysectorsarereflectedinTable5.10andinFigure5.3ThepowerandenergyvaluesgiveninTable5.10arethoseuseainthegenerationplanningstudies.Annualgrowthratesrangefrom1.99to5.96percentforverylowandhighforecastswithamediumgenerationforecastof3.96percent.(b)ForecastIncorporatingLoadManagementandConservationInordertoevaluategenerationplansunderextremelylowprojectedenergygrowthrates,thelowforecastwasfurtheradjusteddownwardtoaccountforadditionalloadmanagementandenergyconservation.TheresultsofthisscenarioalsoappearonTable5.10.5-9 -ISERConservationAssumptionsFortheresidentialsector,ISERassumedthefederally-mandatedefficien-cystandardsforelectricalhomeapplianceswouldbeenforcedfrom1981to1985butthattargetefficiencieswouldbereducedby10percent.Energysavingduetoretrofittingofhomeswasassumedtobeconfinedtosinglefamilyresidencesandtooccurbetween1980and1985.Heatingenergyconsumptionwasassumedtobereducedby4percentinFairbanks,2percentinAnchorageandbetween2and4percentintheGlennallen-Valdezarea.Enforcementofmandatoryconstructionorperformancestandardsfornewhousingwasassumedin1981withareductionoftheheatloadfornewpermanenthomeconstructionby5percent.Inthecommercial-industrial-governmentsector,itwasassumedbyISERthatelectricityrequirementsfornewconstructionwouldbereducedby5percentbetween1985and1990andby10percentduringtheperiod1990to2000.Itwasassumedthatretrofittingmeasureswouldhavenoimpact.-ImpactsofRecentLegislationTheNationalEnergyConservationPolicyActincludesavarietyofincen-tivesandmandatesforenergyconservationandalternativeenergyusebyindividuals,stategovernmentandbusiness.Thenewprogramsconsistofenergyauditsofresidentialcustomersandpublicbuildings,insulationandretrofittingofhomesthroughloanandgrantprograms,improvementofenergyefficiencyofschoolsandhospitals,anduseofsolarenergy.ThePublicUtilitiesRegulatoryPoliciesAct(PURPA)ofNovember9,1978,requiresstatepublicutilitycommissionstoconsidercertainrate-makingstandardsforutilitiesiftheyhavesalesinexcessof500millionkilo-watthours.Theestablishedstandardstobeconsideredare:·Ratestoreflectcostofservice;·Abolitionofdecliningblockrates;·Time-of-dayrates;·Seasonalrates.BothChugachElectric(CEA)andAnchorageMunicipalLightandPowerDepartment(AMLPD)areaffectedbytheprovisionsofPURPAregardingrateandservicestandardsforelectricutilities.AccordingtothereportbytheAlaskaCenterforPolicyStudies(2),theAlaskaPublicUtilitiesCommission(APUC)intendstodealwiththerateandloadmanagementconsiderationscalledforbyPURPAin1981.-StudyAssumptionsTheprogramsofenergyconservationandloadmanagementmeasuresthatcouldbeimplementedinadditiontothoseincludedintheISERforecastarethefollowing:5-10 .Energyprogramsprovidedforintherecentstateenergyconservationlegislation;.Loadmanagementconceptsnowtestedbyutilities,includingratereform,toreflectincrementalcostofserviceandloadcontrols.ThesemeasurescoulddecreasethegrowthrateofenergyandwinterpeakprojectedintheISERforecastandtheforecastsusedingenerationplan-ning.Theimpactswouldbemainlyintheresidentialsector.TheimpactofstateenergyconservationlegislationhasbeenevaluatedinastudybyEnergyProbe(3)whichindicatedthatitcouldreducetheamountofelectricityneededforspaceheatingby47percent.Thetotalgrowthrateinelectricitydemandoverthe1980-2010periodwoulddropfromanaverageof3.98percentperannum(projectedbyISERintheMES-GMfore-cast),to3.49percentperannum.EnergyProbeindicatedthattheelectri-calenergygrowthratecouldbereducedevenfurtherto2.70percentperannumwithaconservationprogrammorestringentthanthatpresentlycontemplatedbytheStatelegislature.Thelowforecastcaseassumedaboveincorporatesanannualgrowthrateof2.71percent.Thisratewouldbereducedwithenforcementofenergycon-servationmeasuresmoreintensivethanthosepresentlyintheStatelegis-lature.Anannualgrowthrateof2.1percentwasjUdgedtobeareasonablelowerlimitforelectricaldemandforpurposesofthisstudy.Thisrepresentsa23percentreductioningrowthratewhichissimilartothereductiondevelopedintheEnergyProbestudy.Theimplementationofloadmanagementmeasureswouldresultinanaddition-alreductioninpeakloaddemand.Theresidentialsectordemandisthemostsensitivetoashiftofloadfromthepeakperiodtotheoff-peakperiod.Overthe1980-2010period,anannualgrowthrateforpeakloadof2.73percentwasusedinthelowforecastcase.Withloadmanagementmeasuressuchasratereformandloadcontrols,thisgrowthratecouldbereducedtoanestimated2.1percent.Theannualloadfactorforyear2010wouldbeincreasedfrom62.2percentinthelowforecastto64.4inthelowestcase.5-11 TABLE5.1-HISTORICALANNUALGROWTHRATESOFELECTRICUTILITYSALESAnchorageandFairbanksPeriodU.S.Areas1940-19508.8%20.5%1950-19608.7%15.3~~1960-19707.3~~12.9%1970-19784.6%11.7%1970-19736.7~~13.1%1973-19783.5%10.9%1940-19787.3%15.2%5-12 TABLE 5.2 -ANNUAL GROWTH RATES IN UTILITY CUSTOMERS AND CONSUMPTION PER CUSTOMER Greater Anchorage Greater Fairbanks U.S. Customers Consumpt ion per Customers Consumpt ion per Customers Consumpt ion per (Thousands)Customer (MWh)(Thousands)Customer (MWh)(Millions)Customer (MWh) Residential 1965 2.7 6.4 8.2 4.8 57.6 4.9 1978 7.7 10.9 17.5 10.2 77.8 8.8 Annual Growth Rate (%)8.4 4.2 6.0 6.0 2.3 4.6 U1 I I-' W Commercial 1965 4.0 -1.3 -7.4 1978 10.2 -2.9 -9.1 Annual Growth Rate (%)7.5 -6.4 -1.6 TABLE 5.3 -UTILITY SALES BY RAIL BELT REGIONS Greater Anchora~Greater F81rbanks Glennallen-Valdez Rallbelt lotal 1 1 1 1 Sales No.of Sales No.of Sales No.of Sales No.of Regional Customers Regional Customers Regional Customers Custorrers Year GWh Share (Thousands)GWh Share (T housands)GWh Share (Thousands)GWh (Thousands) 1965 369 78%31.0 98 21%9.5 6 1%.6 473 41.1 1966 415 32.2 108 9.6 NA NA 523 41.8 1967 461 34.4 66 NA NA NA 527 34.4 1968 519 39.2 141 10.8 NA NA 661 30.0 1969 587 42.B 170 11.6 NA NA 758 54.4 1970 684 75%46.9 213 24%12.6 9 1%.8 907 60.3 1971 797 49.5 251 13.1 10 .9 1059 63.5 1972 906 54.1 262 13.5 6 .4 1174 68.0 1973 1010 56.1 290 13.9 11 1.0 1311 71.0 1974 1086 61.8 322 15.5 14 1.3 1422 78.6 1975 1270 75%66.1 413 24%16.2 24 1%1.9 1707 84.2 01 1976 1463 71.2 423 17.9 33 2.2 1920 91.31.....1977 1603 81.1 447 20.0 42 2.1 2092 103.2 .".1978 1747 79%87.2 432 19%20.4 3B 2%2.0 2217 109.6 Annual Growth 12.7%8.2%12.1%6.1%13.9%9.7'%12.6%7.8% NOTES: (1 )Includes residential and commercial users only,but not miscellaneous users. Source:Federal Energy Regulatory Commission,Power System Statement (_). NA:Not Available. TABLE5.4-RAILBELTELECTRICITYEND-USECONSUMPTION(GWh)Commercial-IndustrialYearResidential-GovernmentMiscellaneous19652142489196624127581967208241819682943551119693394071219704024B9141971478555251972542613171973592698191974651749201975790886281976879101226197794811172119781029115627AverageAnnualGrowth12.8%12.6%8.8%%ofAnnualConsumption196545%53%2%197044%54%2%197546%52%2%197847%52%1%5-15 TA8LE 5.5 -8ASE CASE FORECAST (MES-GM)1 (GWh) Ut111ty Sales to All consuml~9 5e~~~rs Sales MIlItary Self-SupplIea b~enna!len-Net Industry Net Year Anchorage Fairbanks Valdez Total Utility Generation Generation 1980 1907 446 37 2390 334 414 1985 2438 669 64 3171 334 571 1990 2782 742 75 3599 334 571 1995 3564 949 88 4601 334 571 2000 4451 1177 102 5730 334 571 2005 5226 1397 119 6742 334 571 2010 ~141 1671 140 7952 334 571 Average Annual Growth Rate (%) 1980-1990 3.85 5.22 7.32 4.18 0.0 3.27 U1 1990-2000 4.81 4.72 3.12 4.76 0.0 0.0 I 2000-2010 3.27 3.57 3.22 3.33 0.0 0.0 .....1980-2010 3.85 4.50 4.54 4.09 0.0 1.08 '" NOTES: (1)Reproduced from ISER's (_)Medium Economic Growth/Moderate Government Expenditure Scenario (without price induced shift to electr icity). TA8LE 5.6 -SUMMARY OF RAIL8ELT ELECTRICITY PROJECTIONS Military Net Self-Supplied Utility Sales to All Consuming Sectors (GWh)Generation (GWh)Industry Net Generation (GWh) MES-GM MES-GM LES-GL 1 MES-GM with Price HES_GH 1 MES-GM MES-GM with Price Year Bound LES-GM (8ase Case)Induced Shift HES-GM Bound (8ase Case)LES-GM (Base Case)Induced Shift HES-GM 1980 2390 2390 2390 2390 2390 2390 334 414 414 414 414 1985 2798 2921 3171 3171 3561 3707 334 414 571 571 847 1990 3041 3236 3599 3599 4282 4443 334 414 571 571 981 1995 3640 3976 4601 4617 5789 6317 334 414 571 571 981 2000 4468 5101 5730 6525 7192 B010 334 414 571 571 9B1 2005 4912 5617 6742 B219 9177 10596 334 414 571 571 9B1 2010 5442 6179 7952 10142 11736 14009 334 414 571 571 9B1 Average Annual Growth Rate (%) V1 1980-1990 2.44 3.08 4.18 4.18 I 1990-2000 3.92 4.66 4.76 6.13I-'....,2000-2010 1.99 1.94 3.33 4.51 1980-2010 2.78 3.22 4.09 4.94 NOTES: Lower Bound =Estimates for LES-GL Upper Bound =Estimates for HES-GH LES =Low Economic Growth MES =Medium Economic Growth HES =High Economic Growth GL =Low Government Expenditure GM =Moderate Government Expenditure GH =High Government Expenditure (1)Results generated by Acres,all others by ISER (_). 6.00 5.32 5.02 5.45 6.40 6.07 5.75 6.07 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.27 0.0 0.0 1.08 3.27 0.0 0.0 1.08 9.0 0.0 0.0 2.92 TA8LE 5.7 -SUMMARY OF RECENT PRDJECTIDNS OF RAIL8ELT ELECTRIC PDWER REQUIREMENTS (GWh) Study Number/Source 198D 1990 1995 200D 2D25 Low Med High Low Med High Low Med High Low Med High Low Med High 1.South Central Railbelt Area,Alaska Interim feasibility Report:Hydro- electric Power and Related Purposes for the Upper Susitna River Basin, Alaska District Corps of Engineers, Department of the Army,1975.(_) 3D20 3240 355D 5470 648D 8540 6656 8688 12576 81DO 1165D 18520 2.Electric Power in Alaska 1976-1995 Institute of Social and Economic 2478 Research,University of Alaska,1976.(_) 3877 5415 12706 8092 20984 U1 I I-' 00 3.Alaska Electric Power:An Analysis of future Requirements and Supply Alternatives for the Railbelt Region,Battelle Pacific Northwest Laboratories,1978.(__) 26DO 340D 8500 108DO 10341 17552 16000 -22500 4.Upper Susitna River Project Power Market Analyses,U.S.Department of Energy,Alaska Power Administration, 1979;South Central Railbelt Area? Alaska,Upper Susitna River Basin, Supplemental feasibility Report, Corps of Engineers,1979 (_)and Phase I Technical Memorandum: Electric Power Needs Assessment, South Central Alaska Water Resources Committee,1979 (_) 2920 3155 3410 4550 6110 820D 5672 8175 11778 707D 10940 1692D 8110 17770 38020 TABLE5.B-PERFORMANCEOFPASTPROJECTIONSRAILBELTELECTRICPOWERREQUIREMENTS1AnnualGrowthRateofPercentError4NetEnergyBetweeninForecastNetEnergy(GWh)ForecastYear&1980ofGrowth2StudyYearofYearofForecast3RatetoNumberPublicationForecastfor19BOForecastActual19BO(ro)19751851324011.97.3+6321976209329B59.35.9+5B3197B2397300011.94.B+148419792469315527.B6.5+328NOTES:(1)NetEnergyfigurescalculatedfromsalesplus10percentforlosses(2)CorrespondstoTable5.7.(3)Assuming1980NetEnergyconsistingof2390ofsalesplus10percentlosses.(4)Indicatesoverestimation.5-19 TABLE S.9 -FORECAST TOTAL GENERATION ANO PEAK LOAOS -TOTAL RAILBELT REGION 1 ISER Low (LES-GM)Z ISER Medium (MES-GM)I SEll High (HES':GM) Peak Peak Peak Generation Load Generation Load Generation Load Year (GWh)(MW)(GWh)(MW)(GWh)(MW) 1978 3323 606 3323 606 3323 606 19BO 3522 643 3522 643 4135 753 1985 4141 757 4429 BOB 55Z8 99S 1990 4503 BZ4 49ZZ B98 6336 1146 1995 5331 977 6050 1105 B013 1456 ZOOO 6S99 1Z10 73Z7 1341 9S98 17S0 ZOOS 718B 1319 8471 1551 11843 Z1S8 2010 7BZZ 143S 983B 1BOO 14730 Z6B3 U1, N 0 Percent Z.71 Z.73 3.4S 3.46 4.76 4.76 Growth/Yr. 197B-Z010 NOTES: (1)Includes net generation from military and self-supplied industry sources. Source:Reference ( ) (2)All forecasts assume moderate government expenditure. TA8LE5.10-RAIL8ELTREGIONLOADANDENERGYFORECASTSUSEDFORGENERATIONPLANNINGSTUDIESLOA0CASElowplusLoadManagementandLowMediumHighConservation(LES-GL)2(MES-GM)3(HES-GH)4(LES-GLAdjusted)lLoadLoadloadload~MWGWhFactorMWGWhFactorMWGWhFactorMWGWhfactor1980510279062.5510279062.4510279062.4510279062.41985560309062.8580316062.4650357062.6695386063.41990620343063.2640350562.4735403062.6920509063.11995685381063.5795435062.3945517062.51295712062.82000755424063.8950521062.31175643062.41670917062.62005835469064.11045570062.21380753062.322851254062.62010920520064.41140622062.21635894062.429001593062.7Notes:(1)LES-GL:Loweconomicgrowth/lowgovernmentexpenditurewithloadmanagementandconservation.(2)LES-GL:Loweconomicgrowth/lowgovernmentexpenditure.(3)MES-GM:Mediumeconomicgrowth/moderategovernmentexpenditure.(4)HES-GH:Higheconomicgrowth/highgovernmentexpenditure.5-21 5-22HISTORICALTOTALRAILBELTUTILITYSALESTOFINALCUSTOMERSFIGURE5.1IIIRI19801975YEAR1970/VJ17~o196550025002000tI;;:C9(f)1500w..J<{(f)>-f-Ua:f-U1000W..JW, 2°19~8:::0------:1:!98:::5:-----::19!.:9:::0------:1:!9:-95:----2:-0:l:0:-::0:-------:2...JOL05----2...JOIOYEARFIGURE5.21BIRI5-23HIGHECONOMICGROWTH+HIGHGOVERNMENTEXPENDITUREHIGHECONOMICGROWTH+MODERATEGOVERNMENTEXPENDITUREMOOERATEECONOMICGROWTH+MODERATEGCVERNMENTEXPENDITURELOWECONOMICGROWTH+MODERATEGOVERNMENTEXPENDITURELOWECONOMICGROWTH+LOWGOVERNMENTEXPENDITUREFORECASTALTERNATIVETOTALRAILBELTUTILITYSALES,4HES-GH/III/I/I/.-t3I 0t-------------t----------+---~,L.----7"~___I...J«(f)918LEGEND17HES-GH0HES-GM016MES-GM0LES-GM0LES-GL015141312~:I:~II<.!l 20102005IIIIIIIIIIIIIIIHES-GHIIII20001995YEAR,,,,,,,,/~,,,,~,,19901985HES-GH:HIGHECONOMICGROWTH+HIGHGOVERNMENTEXPENDITUREMES-GM:MODERATEECONOMICGRCWTH+MODERATEGOVERNMENTEXPENDITURELES-GL:LOWECONOMICGROWTH+LOWGOVERNMENTEXPEtlDITURELES-GLADJUSTED:LOWECONOMICGROWTH+LOWGOVERNMENTEXPENDITURE+LOADMANAGEMENTANDCONSERVATIONLEGEND45I----------"-::-"f-----;;;'''''--------::;",,..''''-lf------_--=-::;;;;--=.,"--"",,"--LES-GL,,"ADJUSTEDb.e~"":"';::~o:::::=--:::-:::::---r*'!....30L---L--'---'----.l.....J..---'1980II131214152ENERGYFORECASTSUSEDFORGENERATIONPLANNINGSTUDIES16.-----------------------------------"5-24?FIGURE5.3J:;;:10f------------jf----------t-'----------;~I~IzQ9!;(a::wti.8~)0-f-(37ii:f-()~6w LISTOFREFERENCES(1)InstituteofSocialandEconomicResearch,ElectricPowerRequirementsfortheRailbelt,June,1980.(2)AlaskaCenterforPolicyStudies,EnergyAlternativesfortheRailbelt-StudyofEnd-UseStructure,EnergyConservationPotential,AlternativeEnergyResourcesandRelatedPublicPolicyIssues,August,1980.(3)EnergyProbe,AnEvaluationoftheISERElectricityDemandForecast,July,1980.5-25 6 -RAILBELTSYSTEMANDFUTUREPOWERGENERATIONOPTIONS6.1-IntroductionEffectiveplanningoffutureelectricpowergenerationsourcestomeetthepro-·jectedneedsoftheRailbeltRegionmustaddressanumberofconcerns.Apartfromtheobviousgoalofplanningtomeetprojectedpowerandenergyneedsoftheregion,carefulconsiderationmustbegiventothetrade-offswhichwillberequiredinsatisfyingthoseneedswithintheconstraintsoftechnicalfeasi-bility,economicnecessity,acceptableenvironmentalimpactsandsocialprefer-ences.ThehydroelectricpotentialintheSusitnaRiverBasinisbutoneoftheavailableoptionsformeetingfuture·Railbeltdemand.Ifconstructed,theSusitnaBasindevelopmentplanwouldprovideamajorportionoftheRailbeltRegionenergyneedswellbeyondtheyear2000.Inordertoaccuratelydeterminethemosteconomicbasindevelopmentplanwhichclearlydefinesdetailssuchasdamheights,installedgeneratingcapacities,reservoiroperatingrules,damandpowerhousestagingconcepts,andconstructionsche-dules,itisfirstnecessarytoevaluateineconomictermstheplaninthecon-textoftheentireRailbeltgeneratingsystem.ThisrequiresthateconomicanalysesbeundertakenofexpansionalternativesforthetotalRailbeltsystemcontainingseveraldifferenttypesofgeneratingsources.Thesesourcesincludeboththermalandhydropowergeneratingfacilitiescapableofsatisfyingaspeci-fiedloadforecast.EconomicanalysesofscenarioscontainingalternativeSusitnaBasindevelopmentplansbeinginvestigatedwouldthenrevealwhichisthemosteconomicbasindevelopmentplan.Thisprocessandthecomparisonofotherfactorssuchasenvironmentalimpactsandsocialpreferences,essentiallyfallswithinthepurviewof"generationplanning".ThesestudiesarediscussedinmoredetailinSection8.Thissectiondescribestheprocessofassemblingtheinformationnecessarytocarryoutthesesystemwidegenerationplanningstudies.Includedisadis-cussionoftheexistingsystemcharacteristics,theplannedAnchorage-Fairbanksintertie,anddetailsofvariousgeneratingoptionsincludinghydroelectricandthermal,adiscussionoftheimplicationsoftheFuelUseAct(FUA),andabriefoutlineofotheroptionssuchastidalandgeothermalenergygeneration.Per-formanceandcostinformationrequiredforthegenerationplanningstudiesispresentedforthehydroelectricandthermalgenerationoptionsbutnotforthetidalandgeothermaloptions.Preliminaryindicationsarethattheseoptionsareasyetnotcompetitivewiththemoreconventionaloptionsconsidered.Emphasisisplacedoncurrentlyfeasibleandeconomicgeneratingsources.Otheroptionssuchaswind,solarandbiomass-firedgenerationarenotconsideredinthisstudy.AnindependentstudycurrentlybeingundertakenfortheStateofAlaskabyBattellePacificNorthwestLaboratoriesaddressesallsuchoptions.Itshouldbestressedthatthenon-SusitnagenerationoptionshaveonlybeendeaItwithinsufficientdetailtodeveloprepresentativeperformanceandcostdataforinclusioninthealternativeRailbeltsystemgenerationscenarios.TheprimaryobjectiveistocarryoutapreliminaryassessmentofthefeasibilityoftheselectedSusitnaBasindevelopmentplanbycomparingthecostsandbenefitsofthe"withSusitnascenario"withselected"withoutSusitnascenarios".6-1 6.2-ExistingSystemCharacteristics(a)SystemDescriptionThetwomajorloadcentersoftheRai1be1tRegionaretheAnchorage-CookInletareaandtheFairbanks-TananaValleyarea(seeFigure6.1).Atpresent,thesetwoareasoperateindependently.TheexistingtransmissionsystembetweenAnchorageandWillowconsistsofanetworkof115kVand138kVlineswithinterconnectiontoPalmer.Fairbanksisprimarilyservedbya138kVlinefromthe28MWcoalfiredplantatHealy.CommunitiesbetweenWillowandHealyareservedbylocaldistribution.Therearecurrentlynineelectricutilities(includingtheAlaskaPowerAdministration)providingpowerandenergytotheRai1be1tsystem(SeeTable6.1).Inordertoobtaininformationonthecurrent(1980)installedgenerationcapabilityoftheseutilities,thefollowingsourceswereconsulted:(i)PublishedDocuments_WCCReport,"ForecastingPeakE1ectrica1DemandforAlaska'sRailbelt",September,1980(1)._IECOTransmissionReportfortheRai1be1t,1978(2)._U.S.DOE,"InventoryofPowerPlantsintheU.S.,"April1979(3)._ElectricalWorldDirectoryofPublicUtilities1979-1980Edition(4)._WilliamsBrothersEngineeringCompany,1978ReportonFMUSandGVEASystems(5)•.-FERCForm12Aforthefollowingutilities:_AnchorageMunicipalLight&PowerDepartment(AMLPD)-ChugachElectricAssociation(CEA)-HomerElectricAssociation(HEA)-FairbanksMunicipalUtilitySystem(FMUS)(ii)DiscussionsWith:_AnchorageMunicipalLightandPowerDepartment(AMLPD)_FairbanksMunicipalUtilitySystem(FMUS)-CopperValleyElectricAssociation(CVEA)-AlaskaPowerAdministration(APAd)Table6.1summarizestheinformationreceivedfromthesesources.SomediscrepanciesareapparentespeciallywithrespecttoAMLPDandCVEA.TheACREScolumnliststheinstalledcapacitydatausedinthegenerating6-2 6-3ScheduleRetirements30years35years20years30years30years30years50yearsWiththeexceptionoftwohydroelectricplants,thetotalRailbeltinstall-edcapacityof944MWasof1980consistsoffifty-onethermalgenerationunitsfiredbyoil,gasorcoal,assummarizedinTable6.3.Inordertoestablisharetirementpolicyfortheexistinggeneratingunits,severalreferenceswereconsultedincludingtheAPAdraftfeasi-bilitystudygUidelines(6),FERCguidelines,andhistoricalrecords.Utilities,particularlythoseintheFairbanksarea,werealsoconsulted.Basedontheabove,thefollowingretirementperiodsofoperationwereadoptedforuseinthisstudy:TheCOEiscurrentlyinthepost-authorizationplanningphasefortheBradleyLakehydroelectricprojectlocatedontheKenaiPeninsula.Ascurrentlyenvisaged,theprojectincludes94MWofinstalledcapacityandwouldproduceanannualaverageenergyof420Gwh.Forstudypurposes,theprojectisassumedtocomeon-linein1988.OnlytwonewprojectsarecurrentlytobecommittedwithintheRailbeltsystem.TheCEAisintheprocessofadding60MWofgasfiredcombinedcyclecapacityinAnchorage.TheplantwillbecalledBelugaNo.8.Forstudypurposes,theplantisassumedtocomeon-lineinJanuary1982.Table6.2liststheretirementdatesforeachofthecurrentgeneratingunitsbasedontheaboveretirementpolicy.Table6.2includesadetailedlistingofunitscurrentlyoperatingintheRailbelt,informationontheirperformancecharacteristics,andtheiron-lineandassumedretirementdates.ScheduleofAdditions-LargeCoal-FiredStearnTurbines(>100MW):-SmallCoal-FiredSteamTurbines«100MW):-Oil-FiredGasTurbines:-NaturalGas-FiredGasTurbines:-Diesels:-CombinedCycleUnits:-ConventionalHydro:planningstudiesdescribedinthisreportandrepresents.aresolutionofdiscrepanciesindatacollected.-Fairbanks-AnchorageIntertieineeringstudiesarecurrentlybeingundertakenforconstructionofaninter-betweentheAnchorageandFairbankssystems.Aspresentlyenvisaged,thisonwillinvolvea138kVtransmissionlinebetweenWillowandHealyandovidecapabilityfortransferring50MWofcapacityatanytime.Itisedforcompletionin1984.Currentintertiestudiesindicatethatitisctoconstructthisintertiesuchthatitcanbeupgradedtothe345kVitnatransmissioncapabilitywhenWatanacomeson-line. Abriefstudywasundertakentocheckthevalidityoftheassumptionthatafullyinterconnectedsystemshouldbemaintainedasthetotalsystemcapacityincreasesoverthenext30years.Asimplifiedanalysiswascarriedoutinwhichtheeconomicsoftwoalternativeall-thermalgeneratingscenarioswasevaluatedfortheISERmediumloadforecast.Thefirstscenario,calledthe"intertiescenario",allowsforadditionaltransmissiontobeaddedasneeded,withincreasedcapacityrequirementsbeingmetbythemosteconomicgeneratingunitsconstructedinoptimumgeographiclocations.Thesecondscenariorestrictstheintertieto138kVandassumesthatincreasedcapacityrequire-mentswillbemetbyseparatedevelopmentsintheAnchorageandFairbanksareas.BothscenariosincorporatethecommittedCEAcombinedcycle60MWplantin1982andthe94MWBradleyLakehydroplantin1988.After1992,ineitherscenario,additionalgeneratingfacilitieswillberequiredinbothAnchorageandFair-banks.Thepreliminaryeconomiccomparisonwasthereforeonlycarriedoutfortheperiod1980to1992.Theintertiescenariorequiresupgradingoftheexisting138kVlineto230kVandnew230kVlinesfromAnchoragetoWillowandfromHealytoFairbanksin1986.Noadditionalcapacityisnecessary.Thesecondscenariorequires75MWofgasturbinegenerationtomeetthereserverequirementsintheAnchorageareain1988,anda100MWcoal-firedunittosupplementthegenerationcapacityintheFairbanksregionin1986.Thetotalpresentworthcostin1980dollarsofthesecondscenarioexceedsthatofthefirstbyjustover$300million.Theanalysisclearlyindicatesthatitisextremelyeconomictoconstructandmaintainafullyintegratedsystem.Thisconclusionisconservativeasitdoesnotincorporatethebenefitstobederivedforafullyinterconnectedsystemintermsofloadsharingandeconomyenergytransfersaftertheyear1992.Theactualbenefitoftheinterconnectedsystemcouldbesomewhathigherthanesti-mated.Basedontheseevaluations,itwasconcludedthatafullyinterconnectedsystemshouldbeassumedforallthegenerationplanningstudiesoutlinedinthisreport,andthattheintertiefacilitieswouldbecommontoallgenerationscenariosconsidered.Inthepreliminarycomparisonsofalternativegenerationscenarios,thecostofsuchintertiefacilitieswerealsoassumedtobecommon.However,infinalcomparisonsofalessernumberofpreferredalternativescenarios,appropriateconsiderationwasgiventorelativeintertiecosts.Thecostoftransmittingenergyfromaparticulargeneratingsourcetotheintercon-nectedsystemisincludedinallcases.6.4-HydroelectricOptionsNumerousstudiesofhydroelectricpotentialinAlaskahavebeenundertaken.Thesedateasfarbackas1947,andwereperformedbyvariousagenciesincludingthethenFederalPowerCommission,theCOE,theUSBR,theUSGSandtheStateofAlaska.AsignificantamountoftheidentifiedpotentialislocatedintheRailbeltRegion,includingseveralsitesintheSusitnaRiverBasin.AsdiscussedinSection6.1,feasibilityassessmentoftheselectedSusitnaBasindevelopmentplanisbasedoncomparisonsoffutureRailbeltpower6-4 -----------------,generationscenarioswithandwithouttheproject.Anobvious"withoutSusitna"scenarioisonewhichincludeshydroelectricdevelopmentsoutsidetheSustinaBasin.TheplanformulationandselectionmethodologydiscussedinSection1.4andAppendixAhasbeenappliedinthedevelopmentofRailbeltgenerationplanswhichincludeandexcludeSusitna.ThoseplanswhichinvolvetheSusitnaPro-jectarediscussedindetailinSections7and8.ThoseplanswhichincorporatehydroelectricdevelopmentsotherthanSusitnaarediscussedinthisSection.(a)AssessmentofHydroAlternativesTheapplicationofthefive-stepmethodology(Figure1.2)forselectionofnon-Susitnaplanswhichincorporatehydroelectricdevelopments,ispresent-edindetailinAppendixC.ThisprocessissummarizedinthissectionandFigure6.2.Step1ofthisprocessessentiallyestablishedtheoverallob-jectiveoftheexerciseastheselectionofanoptimumRailbeltgenerationplanwhichincorporatedtheproposednon-Susitnahydroelectricdevelop-ments,forcomparisonwithotherplans.UnderStep2oftheselectionprocess,allfeasiblecandidatesiteswereidentifiedforinclusioninthesubsequentscreeningexercise.Atotalof91potentialsites(Figure6.3)wereobtainedfrominventoriesofpotentialsitespublishedintheCaENationalHydropowerStudy(7)andtheAPAdreport"HydroelectricAlternativesfortheAlaskaRailbelt"(8).(b)ScreeningofCandidateSitesThescreeningofsitesrequiredatotaloffoursuccessiveiterationstoreducethenumberofalternativestoamanageableshortlist.Theoverallobjectiveofthisprocesswasdefinedastheselectionofapproximately10sitesforconsiderationinpla~formulation,essentiallyonthebasisofpublisheddataonthesitesandappropriatelydefinedcriteria.Thefirstiterationinthisprocesswasbasedonacoarsescreeninwhichsiteswhichwereconsideredtechnicallyinfeasibleornoteconomicallyviablewerere-jected.Forthispurpose,economicviabilityforasitewasdefinedasenergyproductioncostslessthan50millsperkWh,basedoneconomicpara-meters.Thisvaluewasconsideredtobeareasonableupperlimitconsis-tentwithSusitnaBasinalternatives(SeeSection8).Energyproductioncostswerederivedforeachsiteconsidered,usingthecapitalcostdatapublishedinthecitedreports,updatedto1980levels,andusingpublishedcostescalationdataandanappropriatecontingencyallowance.AsdiscussedinSection8,annualcostswerederivedonthebasisofa 3percentcostofmoney,netofgeneralinflation.Allowancesforoperationandmaintenancecostswerealsoincludedintheseestimates.Forthisinitialscreeningprocess,thereportedenergyyielddataforeachsitewerethenusedasabasisforestimatingannualenergyproductioncostsinmillsperkWh.Asaresultofthisscreen,26siteswererejectedandtheremaining65sitesweresubjectedtoaseconditerationofscreening.Theadditionalcriteriaestablishedforthisscreeningwereenvironmentalinnature.BasedondatapublishedintheCDEandAPAdreports,(7,8)rejectionofsitesoccurredif:6-5 (i)TheywouldcausesignificantimpactswithintheboundariesofanexistingNationalParkoraproclaimedNationalMonumentarea;(ii)Theywerelocatedonariverinwhich:-anadromousfishareknowntoexist;-theannualpassageoffishatthesiteexceeds50,000;- aconfluencewithatributaryoccurs,upstreamofthesite,inwhichamajorspawningorfishingareaislocated.Asaresultofthisscreen,19siteswererejectedandtheremalnlng46sitesweresubjectedtoathirditerationofeconomicandenvironmentalscreening.Atthisstageintheselectionprocess,adjustmentsweremadetocapitalandenergyproductioncostsforeachsitetotakeaccountoftransmissionlinecoststolinkeachsitetotheAnchorage-Fairbanksinter-tie.Arepresentativelistof28siteswasthusderivedbyjudgementaleliminationofthemoreobviouslyuneconomicorlessenvironmentallyaccep-tablesites.Thesesiteswerethencategorizedintosizesasfollows:-lessthan25MW:5sites-25MWto100MW:15sites-greaterthan100MW:8sitesThefourthandfina1screenwasthenperformedinwhichamoredetailednumericalenvironmentalassessmentwasmade.Eightevaluationcriteriawereuti1ized:-Impactonbiggame-Impactonagricultura1potentia1-Impactonwaterfowl,raptorsandendangeredspecies-Impactonanadromousfish-Restrictedlanduses-Impactonwi1dernessareas-Impactoncultural,recreationalandscientificresources-ImpactgeneratedbyaccessTheaboveenvironmentalrankingcriteria\1ereassignednumericalvleights,andscaleratingsforeachsiteandeachcriterionweredevelopedusingavailabledata.Totalscoreswerethencalculatedforeachsitebysummingtheproductsoftheweightandscaleratings.Thisprocessallowedthenumberofsitestobereducedtothe tensiteslistedinTable6.3.(c)PlanFormulationandEvaluationInStep4oftheplanselectionprocess,thetensitesshortlistedunderStep3werefurtherrefinedasabasisforformulationofRailbeltgenera-tionplans.Engineeringsketch-typelayoutswereproducedforeachofthesites,andquantitiesandcapitalcostswereevaluated.ThesecostsarealsolistedinTable6.3andincorporatea20percentallowanceforcontin-genciesand10percentforengineeringandowner'sadministration.AtotaloffiveplanswereformulatedincorporatingvariouscombinationsofthesesitesasinputtotheStep5evaluations.6-6 Powerandenergyvaluesforeachofthedevelopmentswerere-evaluated inStep5utilizingmonthlystreamflowandacomputerreservoirsimulationmodel.DetailsofthesecalculationsaregiveninAppendixFandtheresultsaresummarizedinTable6.3.TheessentialobjectiveofStep5wasestablishedasthederivationoftheoptimumplanforthefutureRailbeltgenerationincorporatingnon-Susitnahydrogenerationaswellasrequiredthermalgeneration.ThemethodologyusedinevaluationofalternativegenerationscenariosfortheRailbeltarediscussedindetailinSection8.ThecriteriaonwhichthepreferredplanwasfinallyselectedintheseactivitieswasleastpresentworthcostbasedoneconomicparametersestablishedinSection8.Theselectedpotentialnon-SusitnaBasinhydrodevelopments(Table6.3)wererankedintermsoftheireconomiccostofenergy.Theywerethenintroducedintotheallthermalgeneratingscenarioduringtheplanninganalyses(SeeSection6.5),ingroupsoftwoorthree.Themosteconomicschemeswereintroducedfirstandwerefollowedbythelesseconomicschemes.TheresultsoftheseanalysesaresummarizedinTable6.4andillustratethataminimumtotalsystemcostof$7040millioncanbeachievedbytheintroductionoftheChakachamna,Keetna,andSnowprojects(SeealsoFigure6.4).AdditionalsitessuchasStrandline,AllisonCreekandTalkeetna-2canalsobeintroducedwithoutsignificantlychangingtheeconomics,andwouldbebeneficialintermsofdisplacingnon-renewableenergyresourceconsump-tion.6.5-ThermalOptionsAsdiscussedearlierinthisSection,themajorportionofgeneratingcapabilityntheRailbeltiscurrentlythermal,principallynaturalgaswithsomecoalandl-firedinstallations.Thereisnodoubtthatthefutureelectricenergyde-intheRailbeltwouldtechnicallybesatisfiedbyanall-thermalgenerationx.Inthefollowingparagraphsanoutlineispresentedofstudiesundertakendetermineanappropriateall-thermalgenerationscenarioforcomparisonwithscenariosinSection8.AmoredetaileddescriptionofthesestudiesmaybefoundinAppendixBofthisreport.(a)AssessmentofThermalAlternativesTheplanformulationandselectionmethodologydiscussedinSection1.4andAppendixA,hasbeenadoptedinamodifiedformtodevelopthenecessaryall-thermalgenerationplans(seeFigure6.5).TheoverallobjectiveestablishedinStep1istheselectionofanoptimumall-thermalRailbeltgenerationplanforcomparisonwithotherplans.InStep2oftheselectionprocess,considerationwasgiventogas,coalandoil-firedgenerationsourcesonly,fromthestandpointoftechnicalandeconomicfeasibilityalone.Thebroaderperspectivesofotheralternative6-7 resourcesandtherelevantenvironmental,socialandotherissuesinvolvedarebeingaddressedintheBattellealternativesstudy.Thisbeingthecase,theStep3screeningprocesswasthereforeconsideredunnecessaryinthisstudyandemphasiswasplacedonselectionofunitsizesappropriateforinclusioninthegenerationplanningexercise.Thusforstudypurposes,thefollowingfivetypesofthermalpowergenerationunitswereconsidered:-Coal-firedsteam-Gas-firedcombined-cycle-Gas-firedgasturbine-OieselToformulateplansincorporatingthesealternativesitwasnecessarytodevelopcapitalcostandfuelcostdatafortheseunitsandotherrelatedoperationalcharacteristics.(b)Coal-FiredSteamAsidefromthemilitarypowerplantatFortWainwrightandtheself-suppliedgenerationattheUniversityofAlaska,therearecurrentlytwocoal-firedsteamplantsinoperationintheRailbelt(seeTable6.1).TheseplantsaresmallincomparisonwithnewunitsunderconsiderationintheLower48andinAlaska.(i)CapitalCostsBasedonthegeneralmagnitudeoftheRailbeltloadrequirements,threecoal-firedunitsizeswerechosenforpotentialcapacityaddi-tions:100,250and500MW.Allnewcoalunitsareestimatedtohaveanaverageheatrateof10,500Btu/kWh,andinvolveanaveragecon-structionperiodoffivetosixyears.Capitalcostsandoperatingparametersare definedforcoalandotherthermalgeneratingplantsonTable6.5.Thesecostsincludea16percentcontingency,a10percentallowanceforconstructionfacilitiesandutilitiesand12percentforengineeringandowner'sadministration.Thecosts\IeredevelopedusingpublisheddatafortheLower48(g)andappropriateAlaskascalingfactorsbasedonstudiesconductedbyBattelle(10).Itisunlikelythata500MWplantwillbeproposedintheFairbanksregionbecauseforecasteddemandthereisinsufficienttojustifyplacingthismuchcapacityonlineatonetime.Therefore,costsforsuchaplantatFairbanksarenotincluded.TosatisfythenationalNewPerformanceStandards(11),thecapitalcostsincorporateprovisionforinstallationoffluegasdesulfuriza-tionforsulphurcontrol,highlyefficientcombustiontechnologyforcontrolofnitrogenacidsandbaghousesforparticulateremoval.6-8 (ii)FuelCostsThetotalestimatedcoalreservesinAlaskaareshownonTable6.6.ProjectedopportunitycostsforAlaskancoalrangefrom$1.00to$1.33permillionBtu.Acostof$1.15wasselectedasthebasecoalcostforgenerationplanning(seeTable6.7).Themarketpriceforcoaliscurrentlywithinthesamegeneralcostrangeastheindicatedoppor-tunitycost.Realgrowthratesincoalcosts(excludinggeneralpriceinflation)arebasedonfuelescalationratesdevelopedbytheDepartmentofEnergy(DOE)(12)inthemid-termEnergyForecastingSystemforDOERegion10whichincludesthestatesofAlaska,Washington,OregonandIdaho.Specifiedpriceescalationratespertainingtotheindustrialsectorwasselectedtoreflectthebulkpurchasingadvantageofutilitiesmoreaccuratelythanequivalentratespertainingtothecommercialandresidentialsectors.Acompositeannualescalationrateof2.93percenthasbeencomputedfortheperiod1980to1995fromthefiveyearlyvaluesgivenbytheOOE.Thiscompositeratehasbeenassumedtoapplytothe1995-2005periodassuggestedbytheDOE.Beyond2005,zerorealgrowthinthecoalpriceisassumed.(iii)OtherPerformanceCharacteristicsAnnualoperationandmaintenancecostsandrepresentativeforcedout-ageratesareshownonTable6.5.c)CombinedCycleAcombinedcycleplantisoneinwhichelectricityisgeneratedpartlyinagasturbineandpartlyinasteamturbinecycle.Combinedcycleplantsachievehigherefficienciesthanconventionalgasturbines.TherearetwocombinedcycleplantsinAlaskaatpresent.Oneisoperationalandtheotherisunderconstruction(SeeTable6.1).TheplantunderconstructionistheBeluga#9unitownedbyChugachElectricAssociation(CEA).Itwilladda60MWsteamturbinetothesystemsometimein1982.(i)CapitalCostsAnewcombinedcycleplantunitsizeof250MWcapacitywasconsideredtoberepresentativeoffutureadditionstogeneratingcapabilityintheAnchoragearea.ThisisbasedoneconomicsizingforplantsintheLower48andprojectedloadincreasesintheRailbelt.Aheatrateof8500Btu/kWhwasadoptedbasedontechnicalpublicationsissuedbytheElectricPowerResearchInstitute(13).Thecapitalcostwasestimatedusingthesamebasisanddatasourcesasforthecoal-firedsteamplantsandislistedinTable6.5.6-9 (ii)FuelCostsThecombinedcyclefacilitieswouldburnonlygaswiththeopportunityvaluerangingfrom$1.08to$2.92permillionBtu.Agascostof$2.00waschosentoreflecttheequitablevalueofgasinAnchorage,assumingdevelopmentoftheexportmarket.Currently,thelocalincrementalgasmarketpriceisabouthalfofthisamountduetotherelativelylightlocaldemandsandlimitedfacilitiesforexport.Usinganapproachsimilartothatusedforcoalcosts,arealannualgrowthrateingascostsof3.98percentwasobtainedfromtheDOEstudiesfor1980to2005.Zeropercentwasassumedthereafter.(iii)OtherPerformanceCharacteristicsAnnualoperationandmaintenancecostsandarepresentativeforcedoutageratearegiveninTable6.5.(d)Gas-TurbineGasturbinesarebyfarthemainsourceofthermalpowergeneratingre-sourcesintheRai1be1tareaatpresent.Thereare470MWofinstalledgasturbinesoperatingonnaturalgasintheAnchorageareaandapproximately168MWofoil-firedgasturbinessupplyingtheFairbanksarea.(SeeTable6.1).Theirlowinitialcost,simplicityofconstructionandoperation,andrelativelyshortimplementationleadtimehavemadethemattractiveasaRai1be1tgeneratingalternative.TheextremelylowcostcontractgasintheAnchorageareaalsohasmadethistype ofgeneratingfacilitycost-effectivefortheAnchorageloadcenter.(i)CapitalCostsAunitsizeof75MWwasconsideredtoberepresentativeofamoderngasturbineplantadditionintheRai1be1tregion.However,thepossibilityofinstallinggasturbineunitsatBelugawasnotcon-sidered,sincetheBelugadevelopmentisatthistimeprimarilybeingconsideredforcoal.Gasturbineplantscanbebuiltoveratwo-yearconstructionperiodandhaveanaverageheatrateofapproximately12,000Btu/kWh.Thecapitalcostwasevaluatedusingthesamedatasourceasforthecoa1-firedplantsandincorporatesa10percentallowanceforconstructionfacilitiesand14percentforengineeringandowner'sadministration.Thiscostincludesprovisionforwetcontrolofairemissions.(ii)FuelCostsGasturbineunitscanbeoperatedonoilasI,e11asnaturalgas.Theopportunityvalueandmarketcostforoilareconsideredtobeequal,at$4.00permillionBtu.Realannualgrowthratesinoilcostsweredevelopedasdescribedaboveandamountedto3.58percentforthe1980-2005periodandzeropercentthereafter.6-10 (iii)OtherPerformanceCharacteristicsAnnualoperationandmaintenancecostsandforcedoutageratesareshowninTable6.5.(e)DieselPowerGenerationMostdieselplantsintheRailbelttodayareonstandbystatusorareoper-atedonlyforpeakloadservice.Nearlyallthecontinuousdutyunitswereretiredinthepastseveralyearsduetohighfuelprices.About65MWofdieselplantcapacityiscurrentlyavailable.(i)CapitalCostsThehighcostofdieselfuelandlowcapitalcostmakesnewdieselplantsmosteffectiveforemergencyuseorinremoteareaswheresmallloadsexist.Aunitsizeof10MWwasselectedasappropriateforthistypeoffacility.ThecapitalcostwasderivedfromthesamesourceasgiveninTable6.5andincludesprovisionforafuelinjec-tionsystemtominimizeairpollution.(ii)FuelCostsDieselfuelcostsandgrowthratesarethesameasoilcostsforgasturbines.(iii)OtherPerformanceCharacteristicsAnnualoperationandmaintenanceandtheforcedoutagerateisgiveninTable6.5.f)PlanFormulationandEvaluationThesixcandidateunittypesandsizesdevelopedunderStep2wereusedtoformulateplansformeetingfutureRailbeltpowergenerationrequirementsinStep4.TheobjectiveofthisexercisewasdefinedastheformulationofappropriateplansformeetingtheprojectRailbeltdemandonthebasisofeconomicpreferences.Twodifferentcasesofnaturalgasconsumptionpolicywereconsideredinformulatingplans.Thefirst,calledthe"renewal"policyallowedfortherenewalofnaturalgasturbinesattheendoftheireconomiclives,antici-patingthepossibleexemptionsthatutilitiesmayobtainfromtheFUA.Thesecondpolicy,calledthe"norenewals"policyassumedthattheutilitieswouldnotbeallowedtoreconstructplantsastheyareretiredandthattheywouldonlybeallowedtoconstructnewplantswithnotmorethan1500hoursofannualoperation(seeCondition9oftheFUAasdiscussedinSection6.6).6-11 Section201oftheFUAprohibitstheuseofpetroleumornaturalgasasaprimaryenergysourceinanynewelectricpowerplantandprecludestheconstructionofanynewpowerplantwithoutthecapabilitytouseanalter-natefuelasaprimaryenergysource.Thereare,however,twelvediffer-entexemptioncategoriesincorporatedintheAct.Plantswhichcanbeincludedinanyofthesecategoriesmayqualifyforapermanentexemption.Theseexemptioncatagoriesare:Figure6.6illustratesthisallthermalgeneratingscenariographically.6.6-ImpactoftheFuelUseAct(a)BackgroundThe"PowerPlantandIndustrialFuelUseActof1978"(FUA),PublicLaw95-620,regulatestheuseofnaturalgasandpetroleumtoreduceimportsandconservescarcenon-renewableresources.Itis,therefore,essentialtounderstandtheimplicationsofthisactandtoincorporateimportantaspectsinthegenerationplanningstudies.InthesubsequentStep5evaluationofthetwobasicplans,theOGP5gener-ationplanningmodelwasutilizedtodevelopaleastcostscenarioincor-poratingthenecessarycoal,oil,andgasfiredgeneratingunits.Theresultsfortheverylow, low,medium,andhighloadforecastsaresummar-izedinTable6.4.Theyindicatethatforthemediumforecastthetotalsystempresentworthcostisslightlyhigherthan$8,100million.AsillustratedbytheresultsdisplayedinTable6.4,thesetwopolicieshaveverysimilareconomicimpacts.Thedifferenceinpresentworthcostsforthemediumforecastamountstoonly$20million.Forpurposesofthisstudy,therefore,itisassumedthatthe"norenewals"policyismoreappropriateandisusedtoberepresentativeoftheallthermalgenerationscenario.6-12CogenerationFuelmixtureEmergencypurposesMaintenanceofreliabilityofservice(shortdevelopmentleadtime)InabilitytoobtainadequatecapitalStateorlocalrequirementsInabilitytocomplywithapplicableenvironmentalrequirementsSitelimitationsPeakloadpowerplantsIntermediateloadpowerplantsLackofalternativefuelsupplyforthefirsttenyearsofusefullifeLackofalternativefuelsupplyatacostwhichdoesnotsubstan-tiallyexceedthecostofusingimportedpetroleum.(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) (b)FUAandtheRailbeltThetwoAnchorageutilities,ChugachElectricAssociation(CEA)andAnchor-ageMunicipalLightandPowerDepartment(AMLPD)havebeenabletomaintainrelativelylowelectricratestotheircustomersbytheuseofnaturalgasfromtheCookInletregion.AsreportedtotheDOEinJuneof1980,CEApaidanaverageof$0.32/Million8tu(MMBtu)forgas,withitscheapestcontractsupplyingitslargestplantwithgasat$0.24/MMBtu.ComparedtotheU.S.averagepriceofover$2.00/MMBtu,thissituationrepresentsanobviousincentiveforthecontinueduseofnaturalgasforelectricgenera-tionbyCEA.AMLPDreportsthatitscostforgasisapproximately$1.00/MMBtu,whichisstillbelowthenationalaverageutilityprice.ThepricedifferencesexistbecauseCEAholdscertainlongtermcontractsatfavorablerates.InspiteofthelowgaspricescurrentlyenjoyedinAnchorage,itisassumedthatthecostofnaturalgaswillriserapidlyassoonassuitableexportfacilitiesnowunderconsiderationaredeveloped.Thus,the"oppor-tunity"costof$2.00/MMBtudiscussedear1ierisconsideredappropriateforfuturesystemcomparisonsandreleventtothediscussionontheFUApresentedhere.ItcanalsobearguedthattheCookInletreservesaresufficientlylargeandthecostofdeliverytopotentialmarketsintheLower48islowenoughtomakeexporttothesestatesfeasible.Assumingthatnewgas-firedgenerationwouldbeeitheragasturbineorgas-firedboilerlocatedintheAnchoragearea,therewouldbenoparti-cularcapitalortimeplanningconstraintsandtheunitwouldbeactivelyusedtomeettheanticipatedload.Undertheseassumptions,theexemptioncategories1through5wouldnotapply.Categories6and7requiretheexistenceofsomestate,localorenviron-mentalrequirementwhichwouldprecludethedevelopmentoftheplantusinganalternativefuel.Asnosuchconstraintisforeseen,itislikelythatthesecategorieswouldapply.Toobtainanexemptionundercategory8,itmustbeshownthatalternativefuelsareinaccessibleduetophysicallimitations,andthattransporta-tion,handlingandstorage,andwastedisposalfacilitiesareunavailableorotherphysicallimitationsexist.Itisnotanticipatedthatgenerationfacilities,includingcoal,areinaccessibleandisthereforenotlikelythatthiscategorywouldapply.Toqualifyforexemption9forpeakloadpower,apetitionermustcertifythattheplantwillbeoperatedsolelyasapeakloadplant.Inaddition,theEPAorappropriatestateadministratormustalsocertifythatalternat-ivefueluse(otherthannaturalgas)willcontributetoconcentrationofapollutantwhichwouldexceedanationalairqualitystandard.However,duetotheshiftinconcernregardingtheuseofgasascomparedtooil,thisrequirementappearstobeliberallyinterpreted.Ifthiscertificationcouldbeobtained,anyplantwouldstillbelimitedinoutputtoonly1500hoursofgenerationperyearatdesigncapacity.AlA(i1tJ;fj[::r"'njtt")('f:\~:~f)ftP\lftr.-l~hj'4~'d:.JvV~\....L.J't...~,~r\...M.I":.lU.8.DepmimentoftheInterior6-13 6-14(a)GeothermalToobtainexemption11,thepetitionermustdemonstrateanefforthasbeenmadetoobtainanadequateandreliablesupplyofanalternatefuelandshowthatsuchasupplywillnotbeavailablefor10yearsoftheusefulplantlife.Thepetitionermustalsoprovethattheearliestpossibleonlinedateforthealternativeisnotsoonenoughtopreventreservecapa-citymarginsbecomingunacceptablylow.Itisnotanticipatedthatexemp-tionswouldbegrantedunderthiscategory.isavailableonlywhenThisexemptioncategoryExemption10forintermediateloadpowerplantspetroleumisusedastheprimaryenergysource.wouldthereforenotapply.Ofthenumerousgeothermalsitesidentifiedinthestate,onlyafewarelocatedintheSouthCentralRegionencompassingtheRailbelt(14).Ofthese,allbutonearelowtemperaturesources(100-200°F)andthereforefeasibleonlyforbuildingorprocessheating.ThehightemperatureKlawasisite,locatedeastofGlennallen,hasbeenrecentlyinvestigatedforelectricpowergenerationpotential(14).Althoughastudyhasbeenmadeforthedevelopmentofthissite,ithasnotbeenfunded.Nopotentialconsumerfortheenergyhasbeenidentified,mainlybecauseitisremotenessfromanyexisting·orplannedmajortransmissionconnectionfromthesitevicinitytopopulatedareastothesouthorwest.Assuggestedbythisstudy,thistype ofenergywouldpossiblybefeasibleiftheAlaskapipelinecorridorbecomespopulatedsincethegeothermalsiteisneartherouteoftheline.Themoreexotictypesofelectricutilitygeneratingstations,suchaswind,biomass,solar,tidalandgeothermalarebeinginvestigatedforapplicationtotheRailbeltintheBattellealternativesstudy.ThesecouldprovideaportionoftheRailbelt'sgeneratingneedsinaconjunctionwithathermalorthermal/hydroelectricgenerationplan.Itisrecognizedthattheseoptionscouldbeincorporatedintothegenerationplan,howeveracursoryreviewofthetwooftheseresourceswhicharemostlikelytobedeveloped(geothermalandtidal)wouldindicatethattheircontributionwouldbeancillarytotheprincipalalternativesdescribedintheprevioussections.Exemption12requiresthatthealternativesourceisatleast30percentmorecostlythansimilarplantoperatingonimportedoilbeforeanexemp-tionisgranted.Theactualcostofnaturalgasdoesnotdirectlyenterintothedecision.Resultsofthestudiesoutlinedinthisreportindicatethattherearecoal-firedandhydroalternativeswhichcanproduceenergyatpriceswellbelowthatassociatedwithimportedoil.Itis,therefore,alsounlikelythatthisexemptionisapplicable.(c)ConclusionsTheAnchorageutilitiesaresubjecttotheprohibitionsoftheFUAforthedevelopmentofnewsourcesofpowergeneration.Existingfacilitiesmaycontinuetousegas,buttheuseofgasinnewfacilitieswillapparentlyberestrictedtopeakloadapplicationsonly.6.7-OtherOptions Baseduponavailabledata,apotentialsitecapacityontheorderofseveralhundredMWmayexist,althoughonlya25MWdevelopmentisdiscussed.UnlessatransmissionloopparallelingAlaskaHighwayRoutes2and4or1isconstructed,thelikelihoodofageothermaldevelopmentatthislocationeconomicallysupplyinganyoftheRailbeltneedsisremote.Geothermalsourceshavethereforenotbeenconsideredfurtherinthisstudy.(b)TidalPowerTheCookInletareahaslongbeenrecognizedashavingsomeofthehighesttidalrangesintheworld,withmeantidesrangesofmorethan30feetatSunrise,onTurnagainArm,26feetatAnchorage,anddecreasingtowardsthelowerreachesofCookInletto15feetorsonearSeldovia.InitialstudiesofCookInlettidalpowerdevelopment(15)haveconcludedthatgenerationfromtidefluctuationistechnicallyfeasibleandnumerousconceptualschemesranginginestimatedcapacityof50MWto25,900MWhavebeendeveloped.PreliminarystudiesindicatethatthetidalpowerwouldrequiresometypeofretimingofenergyproductiontobeusefulintheRai1be1telectricalsystem.Theearliestestimateofon-linedataforatidalplantwouldbethemid1990's.StudiesarecurrentlyunderwaytodevelopmorespecificinformationonhowmuchandwhichportionoftheRai1be1tenergyneedsthistypeofgenerationcouldsupplyandwhatthecostwouldbe.Thisinformationisnotavailableforconsiderationinthisphaseofthegenerationplanningstudies.6-15 Table6.1-TOTALGENERATINGCAPACITYWITHINTHERAIL8ELTSYSTEMRa~IbeltOt~11tyInstalledcapacltt(MW)WCC()IECul)bUE()ELE.wu.l-)ACREsAbbreviationsName198U1978-197919791980AMLPOAnchorageMunicipalLight&PowerDepartment184.0130.5148.0 108.9215.4CEAChugachElectricAssociation420.0411.0402.2 410.9411.0GVEAGoldenValleyElectricAssociation211.0218.6230.0 211.0211.0FMUSFairbanksMunicipalUtilitySystem67.0 65.568.267.467.2CVEADapperValleyElectricAssociation18.013.0MEAMatanuskaElectricAssociation0.90.63.00.90.9HEAHomerElectricAssociation2.69.21.73.52.6SESSewardElectricSystem5.55.55.55.55.5APAdAlaskaPowerAdministration30.030.030.030.0TOTAL909.0870.9901.6838.0943.66-16 Table 6.2 -GENERATING UNITS WITHIN THE RAIL8ELT -1980 R81!be!£SEatlOn UnIt UnIt InstallatIon Heat Rate Installed MInImum MaxImum Fuel RetIrement Utility Name R Type Year (8TU/kWH)Capacity Capacity Capacity Type Year (MW)(MW)(MW) Anchorage AMLPO 1 GT 1962 15,000 14 2 15 NG 1992 Municipal AMLPO 2 GT 1964 15,000 14 2 15 NG 1994 Light &Power AMLPO 3 GT 1968 14,000 15 2 20 NG 1998 Department AMLPO 4 GT 1972 12,000 28.5 2 35 NG 2002 (AMLPO)G.M.Sullivan 5,6,7 CC 1979 8,500 140.9 NA NA NG 2009 Chugach Beluga 1 GT 1969 13,742 15.1 NA NA NG 1998 Electric Beluga 2 GT 1968 13,742 15.1 NA NA NG 1998 Association Beluga 3 GT 1973 13,742 53.5 NA NA NG 2003 (CEA)8eluga 4 GT 1976 13,742 9.3 NA NA NG 2006 Beluga 5 GT 1975 13,742 53.5 NA NA NG 2005 8eluga 6 GT 1976 13,742 67.8 NA NA NG 2006 Beluga 7 GT 1978 13,742 67.8 NA NA NG 2008 Bernice Lake 1 GT 1963 23,440 8.2 NA NA NG 1993 2 GT 1972 23,440 19.6 NA NA NG 2002 3 GT 1978 23,440 24.0 NA NA NG 2008 O"l Internet ional 39,973 1IStation1GT1965 14.5 NA NA NG 1995.....2 GT 1975 14.5 NA NA NG 1995'-J 39,973 13GT197139,973 18.6 NA NA NG 2001 Knik Arm 1 GT 1952 28,264 14.5 NA NA NG 1985 Copper Lake 1 HY 1961 --15.0 NA NA --2011 Golden Valley Healy 1 ST 1967 11,808 25.0 7 27 Coal 2002 Electric 2 IC 1967 14,000 2.7 2 3 Oil 1997 Assoc iat ion North Pole 2 GT 1976 13,500 64.0 5 64 Oil 1996 (GVEA)2 GT 1977 13,000 64.0 25 64 Oil 1997 Zehander 1 GT 1971 14,500 17.65 10 20 Oil 1991 2 GT 1972 14,500 17.65 10 20 Oil 1992 3 GT 1975 14,900 2.5 1 3 Oil 1995 4 GT 1975 14,900 2.5 1 3 Oil 1995 5 IC 1970 14,000 2.5 1 3 Oil 2000 6 IC 1970 14,000 2.5 1 3 Oil 2000 7 IC 1970 14,000 2.5 1 3 Oil 2000 8 IC 1970 14,000 2.5 1 3 Oil 2000 9 IC 1970 14,000 2.5 1 3 Oil 2000 10 IC 1970 14,000 2.5 1 J-Oil 2000 Table 6.2 (Continued) RSllbelf StatIon DOlt UnIt Installat IOn Heat Rate Installed MInImum MaxImum Fuel Retlrement Utility Name #Type Year (8TU/kWH)Capacity Capacity Capacity Type Year (MW)(MW)(MW) Fairbanks Chene 1 5T 1954 14,000 5.0 2 5 Coal 1989 Municipal 2 5T 1952 14,000 2.5 1 2 Coal 1987 Utiltiy 3 5T 1952 14,000 1.5 1 1.5 Coal 1987 5ystem (FMU5)4 GT 1963 16,500 7.0 2 7 Oil 1993 5 5T 1970 14,500 20.0 5 20 Coal 2005 6 GT 1976 12,490 23.1 10 29 Oil 2006 FMU5 1 IC 1967 11,000 2.7 1 3 Oil 1997 2 IC 1968 11,000 2.7 1 3 Oil 1998 3 IC 1968 11,000 2.7 1 3 Oil 1998 Homer [lee.Homer= Assoc iat ion Kenai 1 IC 1979 15,000 0.9 NA NA Oil 2009 (HEA)Pt.Graham 1 IC 1971 15,000 0.2 NA NA Oil 2001 Seldovia 1 IC 1952 15,000 0.3 NA NA Oil 1982 2 IC 1964 15,000 0.6 NA NA Oil 1994 3 IC 1970 15,000 0.6 NA NA Oil 2000 cr> I Matanuska Talkeetna 1 IC 1967 15,000 0.9 NA NA Oil 1997...... 00 Elee.Assoc. (MEA) Seward 5E5 1 IC 1965 15,000 1.5 NA NA Oil 1995 Electric 5ystem (5E5)2 IC 1965 15,000 1.5 NA NA Oil 1995 Alaska Eklutna -HY 1955 --30.0 NA NA --2005 Power Administrat ion (APAd) TOTAL 943.6 Notes: GT =Gas turbine CC =Combined cycle HY =Conventional hydro Ie =Internal Combustion ST =Steam turbine NG =Natural gas NA =Not available (1)This value judged to be unrealistic for large range planning and therefore is adjusted to 15,000 for generation planning studies. Table6.3-OPERATINGANDECONOMICPARAMETERSFORSELECTEDHYDROELECTRICPLANTSMax.AverageEconomic2GrossInstalledAnnualPlantCapit~lCostofHeadCapacityEnerrFactorCostEnergyNo.SiteRiverFt.(MW)(Gwh(%)($10)($/1000Kwh)1SnowSnow6905022050255452BruskasnaNenana23530140532381133KeetnaTalkeetna33010039545463734CacheTalkeetna31050220515641005BrowneNenana19510041047625596Talkeetna-2Talkeetna3505021550500907HicksMatanuska2756024546529848O1akachamnaChakachatna9455001925441480309AllisonAllisonCreek12708334754125105trandlineLakeBeluga810208549126115NOTES:rrr-rnciudingengineeringandownerlsadministrativecostsbutexcludingAFOC.(2)IncludingAFDC,~nsurance,Amortization,andOperationandMaintenanceCosts.6-19 Table 6.4 -RESULTS OF ECONOMIC ANALYSES OF ALTERNATIVE GENERATION SCENARIOS Installed Capac1ty lAw)by lota1 System lota1 System Category in 2010 Installed Present Worth Generation Scenario OGP5 Run 2hermal HYdro Capacity in Cost - Iype Oescr~pt1on Load ForecBst Id.No.oaI Gas 011 2010 (MW)($10 6 ) All Thermal No Renewals Very Low 1 LBT7 500 426 90 144 1160 4930 No Renewals Low L7E1 700 300 40 144 13B5 5920 With Renewals Low L2C7 600 657 30 144 1431 5910 No Renewals Medium LME1 900 B01 50 144 1895 8130 With Renewals Medium LMEJ 900 807 40 144 1891 8110 No Renewals High L7F7 2000 1176 50 144 3370 13520 With Renewals High L2E9 2000 576 130 144 3306 13630 No Renewals Probabilistic LOF3 1100 1176 100 144 3120 8320 Thermal Plus No Renewals Plus:tied ilHTl L7W1 600 576 70 744 1990 7080 Alternative Chakachamna (500)2_1993 Hydro Keetna (100)-1997 No Renewals Plus:Medium LFL7 700 501 10 894 2005 7040 Chakachamna (500)-1993 Keetna (100)-1997 Snow (50)-2002 O"l No Renewals Plus:Medium LWP7 500 576 60 822 1958 7064I N Chakachamna (500)-1993 0 Keetna (100)-1996 StrandIine (20), Allison Creek (8), Snow (50)-1998 No Renewals Plus:Medium LXF1 700 426 30 822 1978 7041 Chakachamna (500)-1993 Keetna (100)-1996 StrandIine (20), Allison Creek (8), Snow (50)-2002 No Renewals Plus:Mediun L403 500 576 30 922 2028 7088 Chakachamna (500)-1993 Keetna (100)-1996 Snow (50),Cache (50), Allison Creek (8), TaIkeetna-2 (50), Strandline (20)-2002 Notes: (1)Incorporating load management and conservation (2)Installed capacity Table 6.5 -SUMMARY OF THERMAL GENERATING RESOURCE PLANT PARAMETERS PLANT TYPE COAL-FIRED STEAM COMBINED GAs Parameter CYCLE TURBINE DIESEL 500 MW 250 MW 100 MW 250 MW 75 MW 10 MW Heat Rate (Btu/kWh)10,500 10,500 10,500 B,500 12,000 11,500 O&M Costs Fixed O&M ($/yr/kW)0.50 1.05 1.30 2.75 2.75 0.50 Variable O&M ($/MWH)1.40 l.BO 2.20 0.30 0.30 5.00 Outa~ Planned Outages (%)11 11 11 14 11 1 Forced outages (%)5 5 5 6 3.B 5 Construction Period (yrs)6 6 5 3 2 0'1 Start-up Time (yrs)6 6 6 4 4, N I-'Total Ca~ital Cost ($mll lon) Railbelt:---175 26 7.7 Beluga:1,130 630 290 Unit Capital Cost ($/kW)1 Railbelt :---72B 250 77B Beluga:2473 2744 3102 Notes: (1)Including AFDC at a percent escalation and 3 percent interest. ,ftt_.".'"_'_~" Table 6.4 -RESULTS OF ECONOMIC ANALYSES OF ALTERNATIVE GENERATION SCENARIOS Installed CapacIty CAw)by lota1 system lotal System Category in 2010 Installed Present Worth Generation Scenario OGP5 Run [herms1 HYdro Capacity in Cost - Iype Deser lpt Ion Load Forecast Id.No.oa1 Gas 011 2010 (MW)($10 6 ) All Thermal No Renewals Very Low 1 LBT7 500 426 90 144 1160 4930 No Renewals Low L7E1 700 300 40 144 13B5 5920 With Renewals Low L2C7 600 657 30 144 1431 5910 No Renewals Medium LME1 900 801 50 144 1895 8130 With Renewals Medium LME3 900 807 40 144 1891 8110 No Renewals High L7F7 2000 1176 50 144 3370 13520 With Renewals High L2E9 2000 576 130 144 3306 13630 No Renewals Probabil ist ic LOF3 1100 1176 100 144 3120 8320 Thermal Plus No Renewals Plus:Medium L7W1 600 576 70 744 1990 70BO Alternative Chakachamna (500)2_199 3 Hydro Keetna (100)-1997 No Renewals Plus:Medium LFL7 700 501 10 894 2005 7040 Chakachamna (500)-1993 Keetna (100)-1997 Snow (50)-2002 CT\No Renewals Plus:Medium LWP7 500 576 60 822 195B 7064 I N Chakachamna (500)-1993 0 Keetna (100)-1996 Strandline (20), Allison Creek (8), Snow (50)-1998 No Renewals Plus:Medium LXF1 700 426 30 822 1978 7041 Chakachamna (500)-1993 Keetna (100)-1996 Strandline (20), Allison Creek (B), Snow (50)-2002 No Renewals Plus:Medium L403 500 576 30 922 202B 708B Chakachamna (500)-1993 Keetna (100)-1996 Snow (50),Cache (50), Allison Creek (8), Talkeetna-2 (50), Strandline (20)-2002 Notes: (1)Incorporating load management and conservation (2)Installed capacity Table 6.5 -SUMMARY OF THERMAL GENERATING RESOURCE PLANT PARAMETERS PLANT TYPE COAL-FIRED SIEAM COMBINED GAS Parameter CYCLE TURBINE DIESEL 500 MW 250 MW 100 MW 250 MW 75 MW 10 MW Heat Rate (Btu/kWh)10,500 10,500 10,500 B,500 12,000 11,500 O&M Costs Fixed O&M ($/yr/kW)0.50 1.05 1.30 2.75 2.75 0.50 Variable O&M ($/MWH)1.40 1.BO 2.20 0.30 0.30 5.00 Outa~ Planned Outages (%)11 11 11 14 11 1 Forced Outages (%)5 5 5 6 3.B 5 Construction Period (yrs)6 6 5 3 2 en Start-up Time (yrs)6 6 6 4 4 I N >-'Total Carital Cost ($mll lon) RaUbeH:---175 26 7.7 Beluga:1,130 630 290 Unit Capital Cost ($/kW)1 RaUbeH:---72B 250 77B Beluga:2473 2744 3102 Notes: (1)Including AFDC at a percent escalation and 3 percent interest. ~,~= Table6.6-ALASKANFUELRESERVESHeatlngApproximateValueReserveFieldReserveBtu/lbCoal(milliontons)Buluga24007200-8900Nenana20007500-9400Kenai3006500-B500Matanuska10010300-14000Gas(billioncubicfeet)NorthSlope29000plusCookInlet4200plusOil(billion.cubicfeet)NorthSlope8400plusCookInlet200Table6.7-FUELCOSTSANaESCALATIONRATESSELECTEDFORGENERATIONPLANNINGSTUDIESNaturalGasFuelIypeParametercoal011EconomicCost-$/MillionBTU2.001.154.00AnnualEscalationRate-%Perlod:1980-20053.982.933.582006-20100006-22 2~r~r~~~61SCALEINMILES6.1.FIGUREMAP6-23LOCATION DATA ON DIFFERENT THERMAL GENERATING SOURCES COMPUTER MODELS TO EVALUATE '", N....SITE SELECTION PREVIOUS STUDIES CRITERIA ECONOMICS ENVIRONMENTAL 4 ITERATIONS ENGENEERING LAYOUTS AND COST STUDIES OBJECTIVE ECONOMICS -POWER AND ENERGY YIELDS -SYSTEM WIDE ECONOMICS CRITERIA ECONOMICS CH,K,S So THERMAL LEGEND FORMULATION OF PLANS INCORPORATING NON-SUSITNA HYDRO GENERATION FIGURE SNOW (S) BRUSKASNA (B) KEETNA (K) CACHE ( CA ) BROWNE (BR) TALKEETNA - 2 (T-2 ) HICKS (H) CHAKACHAMNA (CH) ALLISON CREEK (AC) STRANDLINE LAKE (SL) CH,K CH,K,S CH,K,S,SL,AC CH,K,S,SL,AC CH 1 K,S,SL,AC,CA,T-2 --~STEP NUMBER IN STANDARD PROCESS (APPENDIX A) 6.2. SCALE-MILESIIt,CHEDUALSAPPROXIMATELY40MlLES&,G0-25MW25-IOOMWI.STRANDLINEL.».WHISKERS26.SNOW2.LOWERBELUGA".COAL27.KENAlLOWER,.LOWERLAKECR.".CHUUTNA2B.GERSTLE4.ALLISONCR.".OHIO29.TANANAR.,.CRESCENTLAKE217.LOWERCHULITNA30.BRUSKASNA6.GRANTLAKElB.CACHE31.KANTISHNAR.7.McCLUREBAY19.GREENSTONE".UPPERBELUGAB.UPPERNELLIEJUAN20.TALKEETNA2".COFFEE9.POWERCREEK21.GRANITEGORGE34.GULKANAR.1O.SILVERLAKE22.KEETNA".KLUTINAiI.SOLOMONGULCH23.SHEEPCREEK".BRADLEYLAKE12.TUSTUMENA24.SKWENTNA'7.HICK'SSITE25.TALACHULITNA'B.LOWEFIGURE631GIRILANETOK1CHITNAYENTNACATHEDRALBLUFFSJOHNSONBROWNEJUNCTIONIS.VACHONISTAZILNAKENAILAKECHAKACHAMNA>100MWo39.40.41.42.4'.44.4'•46.47.46.49...'FAIRBANKSSELECTEDALTERNATIVEHYDRCELECTRICSITES 2010SNOWKEETNACHAKACHAMNA20001506,.,.,.,.TIME19901079846PEAKLOAD~LEGEND946TOTALDISPATCHEDENERGY~196019601534426-261954GENERATIONSCENARIOINCORPORATINGTHERMALIj~lmIANDALTERNATIVEHYDROPOWERDEVELOPMENTS-MEDIUMLOADFORECAST-FIGURE6.4628oL_l~~~~~~~["""':""":""":""":""":""":""":""":"""':""":"=~EX~I~ST~IN~G~AN~D~C~O~M~M~IT=T~ED~=====J10 C> I r"'-J PREVIOUS STUDIES UNIT TYPE SELECTION PLAN FORMULATION COMPUTER MODELS TO EVALUATE SYSTEM WI DE ECONOMICS EVALUATION COAL I 100 MW 250 MW OBJECTIVE OBJECTIVE 500 MW GAS RENEWALS COMBINED CYCLE I 250 MW NO GAS RENEWALS NO GAS RENEWALS GAS TURBINE'75 MW ECONOMIC ECONOMIC DIESEL I 10 MW LEGEND ~ FORMULATION OF PLANS INCORPORATING ALL-THERMAL GENERATION STEP NUMBER IN STANDARD PROCESS (APPENDIX A) FIGURE 6.511~~m I ="""""~~M"_~~"'=".'.'=''""""'3""',,"'",",0 ''''=.'''Y'~'""__,,"'"''",M"'~",,",':::'-=CO,'''--.'"""","Y'~) 20102010900""1""1""1""1189518461044t-L..'-LjFIGURE6.61HIRI2000140720001383TIME6-231990ALLTHERMALGENERATIONSCENARIO-MEDIUMLOADFORECAST-1990oHYDROELECTRICH:r:rf:::!COALFIREDTHERMAL~GASFIREDTHERMAL•OILFIREDTHERMAL(NOTSHOWNONNOTE:RESULTSOBTAINEDFROMOGPSRUNLMEIPEAKLOADLEGEND'948TOTALDISPATCHEDENERGY1980715>-(!)ffi4Zw2o103541980·:){'::':If':::':':':f:t:}EXISTINGANDCOMMITTEDoL-======__--'-----.::.:=.:.:::....:==~---l8103J::;:6(!)ooo>-l-e::;ttl«c..>:;:::;:2ooQ 6-29LISTOFREFERENCES(15)AcresAmericanIncorporated,PreliminaryAssessmentofCookInletTidalPower-Phase1,PreparedfortheStateofAlaska,September,1981.U.S.ArmyCorpsofEngineers,NationalHydropowerStudy,July,1979.AlaskaPowerAdministration,HydroelectricAlternativesfortheAlaskaRailbelt,February,1980.Woodward-ClydeConsultants,ForecastingPeakElectricalDemandforAlaska'sRailbelt,September,1980.IECO,TransmissionReportfortheRailbelt,1978.U.S.DepartmentofEnergy,InventoryofPowerPlantsintheU.S.,April,1979.ElectricPowerResearchInstitute,Coal-FiredPowerPlantCapitalCostEstimates-EPRIAF-342(SOA77-402),FinalReport,December,1977.ElectricalWorld,DirectoryofPublicUtilities,1979-1980,87thEdition.WilliamsBrothersEngineeringCompany,ReportonFairbanksMunicipalUtilitySystemandGoldenValleyElectricAssociation,1978.AlaskaPowerAuthority,PlanofStudyforProjectFeasibilityandFERCLicenseApplication,VolumeI,1979.U.S.DepartmentofEnergy,OfficeofConservationandSolarEnergy,FederalEnergyManagementandPlanningPrograms;MethodologyandProceduresforLifeCycleCostAnalyses-AverageFuelCosts,FederalRegister,December,1980.BattellePacificNorthwestLaboratory,AlaskanElectricPower-AnAnalysisofFutureRequirementsandSupplyAlternativesfortheRailbeltRegion,March,1978.TheBureauofNationalAffairs(BNA),BNAPolicyandPracticeSeries:AirPollutionControl,Section101;AmbientAirQualityStandards,SectionIll;StatePolicies,Section121,NewSourcePerformanceStandards,1980.(6)(4)(5)(ll)(2)(3)(9)(7)(8)(1)(12)(13)ElectricPowerResearchInstitute,CombinedCclePowerPlantCaitalCostEstimates-EPRIAF-610(SOA77-402,FinalReport,December,1977.(14)Markle,D.,GeothermalEnergyinAlaska,Geo-HeatUtilizationCenter,April,1979.(10) 7 -SUSITNABASIN7.1-IntroductionThepurposeofthissectionistodescribeclimatological,physicalandenviron-mentalcharacteristicsoftheSusitnaRiverBasinandtobrieflyacquaintthereaderwithsomeoftheongoingstudiesbeingundertakentoaugmentpreviouslyrecordeddata.Itdealswithgeneraldescriptionsoftheclimatology,hydrologyandgeology,andseismicconsiderationsandoutlinestheenvironmentalaspects.Theinformationpresentedhasbeenobtainedbothfrompreviousstudiesandthefieldprogramsandofficestudiesinitiatedduring1980underTasks3,4,5and7.7.2-Climatology.andHydrologyTheclimateoftheSusitnaBasinupstreamfromTalkeetnaisgenerallycharac-terizedbycold,drywintersandwarm,moderatelymoistsummers.Theupperbasinisdominatedbycontinentalclimatjcconditionswhilethelowerbasinfallswithinazoneoftransitionbetweenmaritimeandcontinentalclimaticinfluences.(a)ClimaticDataRecordsDataonprecipitation,temperatureandotherclimaticparametershavebeencollectedbyNOAAatseveralstationsinthesouthcentralregionofAlaskasince1941.Priortothecurrentstudies,therewerenostationslocatedwithintheSusitnabasinupstreamfromTalkeetna.Thecloseststationswherelong-termclimatedataisavailableareatTalkeetnatothesouthandSummittothenorth.Asummaryoftheprecipitationandtempera-turedataavailableinthevicinityofthebasinispresentedinTable7.1.Sixautomaticclimatestationswereestablishedintheupperbasinduring1980(seeFigure7.1).Thedatacurrentlybeingcollectedatthesestationsincludesairtemperature,averagewindspeed,winddirection,peakwindgust,relativehumidity,precipitation,andsolarradiation.SnowfallamountsarebeingmeasuredinaheatedprecipitationbucketattheWatanastation.DataarerecordedatthirtyminuteintervalsattheSusitnaGlacierstationandatfifteenminuteintervalsatallotherstations.(b)PrecipitationPrecipitationinthebasinvariesfromlowtomoderateamountsinthelowerelevationstoheavyinthemountains.Meanannualprecipitationofover80inchesisestimatedtooccuratelevationsabove3000feetintheTalkeetnaMountainsandtheAlaskanRangewhereasatTalkeetnastation,atelevation345feet,theaverageannualprecipitationrecordedisabout28inches.Theaverageprecipitationreducesinanortherlydirectionastheconti-nentalclimatestartstopredominate.AtSummitstation,atelevation2397feet,theaverageannualprecipitationisonly18inches.Theseasonaldistributionofprecipitationissimilarforallthestationsinandsurroundingthebasin.AtTalkeetna,recordsshowthat68percentofthetotalprecipitationoccursduringthewarmermonths,MaythroughOctober,7-1 whileonly32percentisrecordedinthewintermonths.AveragerecordedsnowfallatTalkeetnaisabout106inches.Generally,snowfallisre-strictedtothemonthsofOctoberthroughAprilwithsome82percentsnowfallrecordedintheperiodNovembertoMarch.TheU.S.SoilConservationService(SCS)operatesanetworkofsnowcoursestationsinthebasinandrecordsofsnowdepthsandwatercontentareavailableasfarbackas1964.ThestationswithintheUpperSusitnaBasinaregenerallylocatedatelevationsbelow3000feetandindicatethatannualsnowaccumulationsarearound20to40inchesandthatpeakdepthsoccurinlateMarch.Therearenohistoricaldataforthehighereleva-tions.Thebasicnetworkwasexpandedduring1980withtheadditionofthreenewsnowcoursesontheSusitnaglacier(seeFigure7.1).Arrange-mentshavebeenmadewithSCSforcontinuingthecollectionofinformationfromtheexpandednetworkduringthestudyperiod.(c)TemperatureTypicaltemperaturesobservedfromhistoricalrecordsattheTalkeetnaandSummitstationsarepresentedinTable7.2.Itisexpectedthatthetemperaturesatthedamsiteswillbesomewherebetweenthevaluesobservedatthesestations.(d)RiverIceTheSusitnaRiverusuallystartstofreezeupbylateOctober.Rivericeconditionssuchasthicknessandstrengthvaryaccordingtotheriverchannelshapeandslope,andmoreimportantly,withriverdischarge.Periodicmeasurementsoficethicknessatseverallocationsintheriverhavebeencarriedoutduringthewintersof1961through1972.ThemaximumthicknessesobservedatselectedlocationsontheriveraregiveninTable7.3.IcebreakupintherivercommencesbylateAprilorearlyMayandicejamsoccasionallyoccuratriverconstrictionsresultinginrisesinwaterlevelofupto20feet.Detailedfielddatacollectionprogramsandstudiesareunderwaytoiden-tifypotentialproblemareasshouldtheSusitnaProjectbeundertaken,andtodevelopappropriatemitigationmeasures.Theprogramincludescompre-hensiveaerialandgroundreconnaissanceanddocumentationoffreeze-upandbreak-upprocesses.Thisdatawillbeusedtocalibratecomputermodelswhichcanbeusedtopredicttheicecoverregimeunderpostprojectconditions.Itwillthenbepossibletoevaluatetheimpactsofanticipatedchangesiniceconditionscausedbytheprojectandanyproposedmitigationmeasures.(e)WaterResourcesStreamflowdatahasbeenrecordedbytheUSGSforanumberofyearsatatotalof12gagingstationsontheSusitnaRiveranditstributaries(seeFigure7.1).Thelengthoftheserecordsvariesfrom30yearsatGoldCreektoaboutfiveyearsattheSusitnastation.Therearenohistoricalrecordsofstreamflowatanyoftheproposeddamsites.Forcurrentstudy7-2 purposes,availablestreamflowrecordshavebeenextendedtocoverthefull30yearperiodusingamultisitecorrelationtechniquetofillthegapsinflowdataateachofthestations.Flowsequencesatthedamsiteshavesubsequentlybeengeneratedforthesame30yearperiodbyextrapolationonthebasisofdrainagebasinareas.AgagingstationwasestablishedattheWatanadamsiteinJune1980andcontinuousriverstagedataisbeingcollected.Itisproposedtodeveloparatingcurveatthestationwithstreamflowmeasurementstakenduringthe1980and1981seasons.RiverflowswillbecalculatedandusedtochecktheextrapolatedstreamflowdataattheWatanasite.Seasonalvariationofflowsisextremeandrangesfromverylowvaluesinwinter(OctobertoApril)tohighsummervalues(MaytoSeptember).FortheSusitnaRiveratGoldCreektheaveragewinterandsummerflowsare2100and20,250cfsrespectively,i.e.a 1to10ratio.ThemonthlyaverageflowsintheSusitnaRiveratGoldCreekaregiveninFigure7.3.Onaverage,approximately88percentofthestreamflowrecordedatGoldCreekstationoccursduringthesummermonths.Athigherelevationsinthebasinthedistributionofflowsisconcentratedevenmoreinthesummermonths.FortheMaclarenRivernearPaxson(El4520ft)theaveragewinterandsummerflowsare144and2100cfsrespectively,i.e.a 1to15ratio.ThemonthlypercentofannualdischargeandmeanmonthlydischargesfortheSusitnaRiveratthegagingstationsaregiveninTable7.4.TheSusitnaRiverabovetheconfluencewiththeChulitnaRivercontributesonlyapproximately20percentofthemeanannualflowmeasurednearCookInlet(atSusitnastation).Figure7.2showshowthemeanannualflowoftheSusitnaincreasestowardsthemouthoftheriveratCookInlet.(f)FloodsThemostcommoncausesoffloodpeaksintheSusitnaRiverBasinaresnow-meltoracombinationofsnowmeltandrainfalloveralargearea.AnnualmaximumpeakdischargesgenerallyoccurbetweenMayandOctoberwiththemajority,approximately60percent,occurringinJune.SomeoftheannualmaximumfloodpeakshavealsooccurredinAugustorlaterandaretheresultofheavyrainsoverlargeareasaugmentedbysignificantsnowmeltfromhigherelevationsandglacialrunoff.AregionalfloodfrequencyanalysishasbeencarriedoutusingtherecordedfloodsintheSusitnaRiveranditsprincipletributaries,aswellastheCopper,MatanuskaandTosinaRivers.Theseanalyseshavebeenconductedfortwodifferenttimeperiodswithintheyear.Thefirstperiodselectedistheopenwaterperiod,i.e.aftertheicebreakupandbeforefreezeup.Thisperiodcontainsthelargestfloodswhichmustbeaccommodatedbytheproject.Thesecondperiodrepresentsthatportionoftimeduringwhichiceconditionsoccurintheriver.Thesefloods,althoughsmaller,canbeaccompaniedbyicejamming,andmustbeconsideredduringtheconstructionphaseoftheprojectinplanninganddesignofcofferdamsforriverdiversion.Theresultsofthesefrequencyanalyseswillbeusedforestimatingfloodsinungagedriversandstreams.TheywillalsobeusedtochecktheaccuracyoftheGoldCreekStationratingcurvewhichisimportantin7-3l! determiningspillwaydesignfloodsfortheproposedSusitnaRiverprojects.Multipleregressionequationshavebeendevelopedusingphysiographicparametersofthebasinsuchascatchmentarea,streamlength,meanannualprecipitation,etc.toassessfloodpeaksatthedamsitesandinter-mediatepointsofinterestintheriver.Table7.5listsmeanannual,100and10,000yearfloodpeaksaswellasthe50yearfloodpeaksunderwaterandundericecoverconditions.Theselatterfloodpeaksareincludedastheyarerepresentativeofthefloodconditionsforwhichtheconstructiondiversionfacilitiesmustbedesigned.EstimatesoftheprobablemaximumfloodsintheSusitnaBasinweremadebyCOEintheir1975study(PMF).Ariverbasincomputersimulationmodel(SSARR)wasusedforthatpurpose.AdetailedreviewoftheinputdatatothemodelhasbeenundertakenanddiscussionsheldwithCOEengineerstoimproveunderstandingofthemodelparametersused.Aseriesofcomputerrunswiththemodelhavebeenundertakentostudytheeffectsoflikelychangesinthetimingandmagnitudeofthreeimportantparameters,i.e.probablemaximumprecipitation,snowpackandtemperature.ThesestudieshaveindicatedthatthePMFisextremelysensitivetocertainoftheseparametersandthatadditionalrefinementofthefloodestimationtechniqueiswarranted.(g)RiverSedimentPeriodicsuspendedsedimentsampleshavebeencollectedbytheUSGSatthefourgagingstationsupstreamfromGoldCreek(seeFigure7.1)forvaryingperiodsbetween1952and1979.ExceptforthreesamplescollectedatDenaliin1958,nobedloadsamplinghasbeenundertakenatanystations.Datacoverageduringhigh-flow,highsedimenteventsispoorandconse-quentlyanyestimateoftotalannualsedimentyieldhasahighdegreeofuncertainty.ThemostcomprehensiveanalysisofsedimentloadintherivertodateisthatundertakenbytheCOEin1975.Table7.6givestheCOEestimatesofsedimenttransportatthegagingstations.7.3-RegionalGeologyTheregionalgeologyoftheareainwhichtheSusitnaBasinislocatedhasbeenextensivelystudiedanddocumented(1,2).TheUpperSusitnaBasinlieswithinwhatisgeologicallycalledtheTalkeetnaMountainsarea.Thisareaisgeologicallycomplexandhasahistoryofatleastthreeperiodsofmajortectonicdeformation.Theoldestrocks(250to300m.y.b.p.)*exposedintheregionarevolcanicflowsandlimestoneswhichareoverlainbysandstonesandshalesdatedapproximately150to200m.y.b.p.Atectoniceventapproximately135to180m.y.b.p.resultedintheinstrusionoflargedioriteandgraniteplutons,whichcausedintensethermalmetamorphism.Thiswasfollowedbymarinedepositionofsiltsandclays.TheargillitesandphylliteswhichpredominateatDevilCanyonwereformedfromthesiltsandclaysduringfaultingandfoldingoftheTalkeetnaMountainsareaintheLateCretaceous*m.y.b.p.:millionyearsbeforepresent7-4 period(65to100m.y.b.p.).Asaresultofthisfaultinganduplift,theeasternportionoftheareawaselevated,andtheoldestvolcanicsandsedimentswerethrustovertheyoungermetamorphicsandsediments.ThemajorareaofdeformationduringthisperiodofactivitywassoutheastofDevilCanyonandincludedtheWatanaarea.TheTalkeetnaThrustFault,awell-knowntectonicfeaturewhichhasbeenidentifiedintheliterature(noteWCCreport),trendsnorthwestthroughthisregion.Thisfaultwasoneofthemajormechanismsofthisoverthrustingfromsoutheasttonorthwest.TheDevilCanyonareawasprobablydeformedandsubjectedtotectonicstressduringthesameperiod,butnomajordeformationsare'evidentatthesite(Figure7.4).ThedioriteplutonthatformsthebedrockoftheWatanasitewasintrudedintosedimentsandvolcanicsabout65m.y.b.p.Theandesiteandbasaltflowsnearthesitemayhavebeenformedimmediatelyafterthisplutonicintrusion,orafteraperiodoferosionandminordeposition.DuringtheTertiaryperiod(20to40m.y.b.p.)theareasurroundingthesiteswasagainupliftedbyasmuchas3,000feet.Sincethenwidespreaderosionhasremovedmuchoftheoldersedimentaryandvolcanicrocks.DuringthelastseveralmillionyearsatleasttwoalpineglaciationshavecarvedtheTalkeetnaMountainsintotheridges,peaks,andbroadglacialplateausseentoday.Post-glacialuplifthasinduceddowncuttingofstreamsandrivers,resultinginthe500to700feetdeepV-shapedcanyonsthatareevidenttoday,particularlyattheVeeandDevilCanyondamsites.Thiserosionisbelievedtobestilloccurringandvirtuallyallstreamsandriversintheregionareconsideredtobeactivelydowncutting.Thiscontinuingerosionhasremovedmuchoftheglacialdebrisathigherelevationsbutverylittlealluvialdepositionhasoccurred.Theresultinglandscapeconsistsofbarrenbedrockmountains,glacialtillcoveredplains,andexposedbedrockcliffsincanyonsandalongstreams.Thearcticclimatehasretardeddevelopmentoftopsoil.Furthergeologicmappingoftheprojectareaandgeotechnicalinvestigationoftheproposeddamsiteswasinitiatedunderthecurrentstudyin1980,andwillcontinuethroughearly1982.7.4-SeismicAspectsRelativelylittledetailedinvestigationoftheseismologyoftheSusitnaBasinareahadbeenundertakenpriortothecurrentstudies.Acomprehensiveprogramoffieldworkandinvestigationofseismicitywasinitiatedin1980.TheseismicstudiesreferredtointhefollowingsectionswerespecificallyaimedatdevelopingdesigncriteriafortheDevilCanyonandWatanadamsites.However,muchofthediscussionispertinenttoalldamsitesintheSusitnaBasinandisthereforeincludedinthissection.(a)SeismicGeologyTheTalkeetnaMountainsregionofsouth-centralAlaskalieswithintheTalkeetnaTerrain.Thistermisthedesignationgiventotheimmediateregionofsouth-centralAlaskathatincludestheupperSusitnaRiverbasin(asshownonFigure7.4).Theregionisboundedo~thenorthbytheDenaliFault,andonthewestbytheAlaskaPeninsulafeaturesthatmakeuptheCentralAlaskaRange.SouthoftheTalkeetnaMountains,theTalkeetnaTerrainisseparatedfromtheChugachMountainsbytheCastleMountain7-5 Fault.TheproposedSusltnaHydroelectricProjectdamsitesarelocatedinthewesternhalfoftheTalkeetnaTerrain.Theeasternhalfoftheregionincludestherelativelyinactive,ancientzoneofsedimentsundertheCopperRiverBasinandisboundedontheeastbytheTotschundasectionoftheDenaliFaultandthevolcanicWrangellMountains.RegionalearthquakeactivityintheprojectareaiscloselyrelatedtotheplatetectonicsofAlaska.ThePacificPlateisunderthrustingtheNorthAmericanPlateinthisregion.ThemajorearthquakesofAlaska,includingtheGoodFridayearthquakeof1964,haveprimarilyoccurredalongtheboundarybetweentheseplates.ThehistoricalseismicityinthevicinityofthedamsitesisassociatedwithcrustalearthquakeswithintheNorthAmericanPlateandtheshallowanddeepearthquakesgeneratedwithintheBenioffZone,whichunderliestheprojectarea.HistoricaldatarevealsthatthemajorsourceofearthquakesinthesiteregionisinthedeepportionoftheBenioffZone,withdepthsrangingbetween24to36milesbelowthesurface.Severalmoderatesizeearthquakeshavebeenreportedtohavebeengeneratedatthesedepths.ThecrustalseismicitywithintheTalkeetnaTerrainisverylowbasedonhistoricalrecords.MostoftherecordedearthquakesintheareaarereportedtoberelatedtotheDenali-ToschundaFault,theCastleMountainFaultortheBenioffZone.(b)FieldInvestigationsForprojectdesignpurposes,itisimportanttoidentifythesurfaceexpressionsofpotentialseismicactivity.WithintheTalkeetnaTerrain,numerouslineamentsandfeatureswereinvestigatedaspartofthe1980seismicstudies.Utilizingavailableairphotos,satelliteimageryandairborneremotesensingdata,acatalogofreportedandobservablediscon-tinuitiesandlinearfeatures(lineaments)wascompiled.Aftereliminationofthosefeaturesthatwerejudgedtohavebeencausedbyglaciation,bedding,riverprocesses,orman'simpact,the216remainingfeatureswerescreened.The48significantfeaturespassingthescreenwerethenclassi-fiedaseitherbeingfeaturesthatcouldpositivelybeidentifiedasfaults,orfeatureswhichcouldpossiblybefaultsbutforwhichadefinitiveorigincouldnotbeidentified.Thefollowingcriteriawereusedinthescreeningprocess:-Alllineamentsorfaultsthathavebeensubjectedtorecentdisplacementareretainedforfurtherstudy.-Alllineamentslocatedwithin6milesofprojectstructures,orhavingabranchthatissuspectedofpassingthroughastructureisretainedforfurtherstudyunlessthereisevidencethattheyhavenotexperienceddisplacementinthelast100,000years.-Allfeaturesidentifiedasfaultswhichhaveexperiencedmovementinthelast100,000yearsareretained.TheseguidelineswereformulatedafterreviewofregulatoryrequirementsoftheWPRS,COE,U.S.NuclearRegulatoryCommission,FederalEnergyRegulatoryCommission,andseveralstateregulations.7-6 Ofthe48candidatefeatures,only13featureswerejudgedtobesignifi-cantforthedesignoftheproject.These13featuresincludefourfea-turesattheWatanasite(includingtheTalkeetnaFaultandtheSusitnafeature)andninefeaturesattheDevilCanyonsite.Itisworthnotingthatnoevidenceofasurfaceexpressionwasobservedinthevicinityoftheso-calledSusitnafeatureduringthe1980studies.Thesethirteenfeatureswillbefurtherinvesti9atedduring1981toestablishtheirpotentialimpactontheprojectdesign.(c)MicroseismicMonitoringTosupporttheidentificationofpotentialfaultsintheprojectarea,ashort-termmicroseismicmonitoringnetworkwasinstalledandoperatedforthreemonths.Theobjectiveofthisexercisewastocollectmicroearth-quakedataasabasisforstudyingthetypesoffaultingandstressorien-tationwithinthecrust,thecorrelationofmicroearthquakeswithsurfacefaultsandlineaments,andseismicwavepropagationcharacteristics.Atotalof265earthquakeswithsensitivityapproachingmagnitudezerowererecorded.Oftheseevents,170wererecordedatshallowdepths,thelargestbeingmagnitude2.8(RichterScale).Ninety-eighteventswererelatedtotheBenioffZone,thelargestbeingmagnitude3.7.NoneofthemicroearthquakesrecordedatshallowdepthswerefoundtoberelatedtoanysurfacefeatureorlineamentwithintheTalkeetnaTerrain,includingtheTalkeetnaFault.ThedepthoftheBenioffZonewasdistinctlydefinedbythisdataasbeing36milesbelowtheDevilCanyonsiteand39milesbelowtheWatanasite.(d)ReservoirInducedSeismicityThesubjectofReservoirInducedSeismicity(RIS)wasstudiedforthepro-posedprojectareaonapreliminarybasisusingworldwideRISdataandsitespecificinformation.ThephenomenonofRIShasbeenobservedatnumerouslargereservoirswhereseismictremorsunderorimmediatelyadjacenttothereservoirhavebeencorrelatedtoperiodsofhighfillingrate.Inrecentyears,thissubjecthasdrawnconsiderableattentionwithintheengineeringandseismiccommunity.ItisthoughtthatRISmaybecausedbythein-creasedweightofthewaterinthereservoirorbyincreasedporepressuresmigratingthroughand"lubricating"jointsintherockandactinghydrauli-callyuponhighlystressedrock.Studiesindicatethatforareservoirsystemtotriggerasignificantearthquake,apre-existingfaultwithrecentdisplacementmustbeunderorveryneartothereservoir.Thepresenceofafaultwithrecentdisplacementhasnotbeenconfirmedateithersite.TheanalysisofpreviouslyreportedcasesindicatedahighprobabilityofRISfortheproposedSusitnareservioronthebasisofitsdepthandvolume,iffaultswithrecentdisplacementexistnearby.MostRISrecordedeventsarebelievedtobeduetoanearlyreleaseofstoredenergyinafault.Thus,inservingasamechanismforenergyrelease,theresultantearthquakesarelikelytobesmallerthaniffullenergybuilduphadoccurred.InnocasestudiedhasanRISeventexceededtheestimatedmaximumcredibleearthquakeonarelatedfault.Therefore,RISofitself7-7 willnotcontrolthedesignearthquakedeterminationandisconsideredonlyforpurposesofestimatingrecurrenceintervalsofpotentialevents.(e)PreliminaryGroundMotionEvaluationsOnthebasisofthegeologicandseismicstudies,threemainsourcesofpotentialearthquakeshavebeenidentifiedatthistime.ThesesourcesaretheDenaliFaultlocatedroughly40milesnorthofthesites,CastleMountainFaultlessthan60milessouthofthesitesandtheBenioffZone30to36milesbelowthesurface.Noevidencehasyetbeenfoundto'indicatethatanyofthefeaturesandlineamentsidentifiedtodatecouldberegardedassurfaceexpressionsoffaultsthathaveexperienceddis-placementduringrecentgeologictimes.Thus,forcurrentstudypurposes,noattemptismadetoassignpotentialearthquakemagnitudestothe13featuresidentifiedaswarrantingfurtherstudy.Furtherfieldstudieswillbeconductedonthesefeaturesduring1981toensurethateliminatingthemfromconsiderationisjustified.Forpreliminaryprojectdesignpuroses,veryconservativeassumptionshavebeenmadeforanticipatedgroundmotionswhichwouldbecausedbypossibleearthquakesoccurringonthethreefaults.TheDenaliFaulthasbeenassignedapreliminaryconservativemaximumcredibleearthquakevalueofmagnitude8.5.Thisearthquake,whenattenuatedtothesites,ispostu-latedtogenerateameanpeakaccelerationof0.21gatboththeWatanaandDevilCanyonsites.TheCastleMountainFaulthasbeenassignedapreli-minaryconservativevalueofmagnitude7.4,whichwouldgenerateameanpeakaccelerationinthe0.05gto0.06grangeatthesites.TheBenioffZonehasbeenassignedanupperboundconservativevalueofmagnitude8.5,whichwouldgenerateameanpeakaccelerationof0.41gattheWatanasiteand0.37gattheDevilCanyonsite.ThedurationofpotentialstrongmotionearthquakesforboththeDenaliandBenioffZonesisconservativelyestimatedtobe45seconds.Itisevidentthatofthesethreepotentialsources,theBenioffZonewillgovernthedesign.FurtherstudieswillbeundertakentofinalizethesemaximumcredibleearthquakemagnitudesandtofurtherevaluatethefeaturesidentifiedwithintheTalkeetnaTerrain.Thereiseveryindicationthatfurtherstudywillleadtoareductioninthedesignearthquakemagnitudesforthethreeknownfaults.Duetotheirdistantlocations,noneofthesefaultshaveanypotentialforcausinggroundruptureatthesites.°Numerous1argedamshavebeendesignedtoaccommodategroundmotionsfromrelativelylargeearthquakeslocatedclosetothedam.InCalifornia,damsareroutinelydesignedtowithstandgroundmotionsfrommagnitude7.5to8.5earthquakesatdistancesof12miles.Damshavealsobeendesignedtoaccommodateupto20feetofhorizontaldisplacementandthreefeetofverticaldisplacement.AlloftheseconditionsaremoreseverethanthoseanticipatedattheSusitnasites.OrovilleDamincentralCaliforniawasdesignedtowithstand severeseismicloadingsandhasbeenprogressivelyanalyzedasnewdataandmethodsbecomeavailable.Currentevaluationsindicatethatthedam,whichiscomparableinsizetoWatana,couldwith-standseismicloadingscomparabletothosepostulatedfortheWatanaandDevilCanyonsites.7-8 7.5-EnvironmentalAspectsNumerousstudiesoftheenvironmentalcharacteristicsoftheSusitnaRiverBasinhavebeenundertakeninthepast.Thecurrentstudieswereinitiatedinearly1980andareplannedtocontinueindefinitely.ThesestudiesconstitutethemostcomprehensiveanddetailedexaminationoftheSusitnaBasineverunder-taken,andpossiblyofanycomparableresource.Inthissection,descriptionsofambientbiologicalandvegetationconditionsarepresented.Thesedescriptionsarebasedonreviewsoftheliteratureaswellasthepreliminaryresultsofon-goingstudies.(a)Biological(i)FisheriesTheSusitnabasinisinhabitedbyresidentandanadromousfish.TheanadromousgroupincludesfivespeciesofPacificsalmon:sockeye(red);coho(silver);chinook(king);pink(humpback);andchum(dog)salmon.DollyVardenarealsopresentinthelowerSusitnaBasinwithbothresidentandanadromouspopulations.AnadromoussmeltareknowntorunuptheSusitnaRiverasfarastheDeshkaRiverabout40milesfromCookInlet.SalmonareknowntomigrateuptheSusitnaRivertospawnintributarystreams.SurveystodateindicatethatsalmonareunabletomigratethroughDevilCanyonintotheUpperSusitnaRiverBasin.Tovaryingdegreesspawningisalsoknowntooccurinfreshwaters·loughsandsidechannels.Foranumberofyearsinthepast,distributiondatahasbeencollectedforthelowerSusitnaRiverandtributaries.Aspartoftheongoingstudies,additionalresourceandpopulationinformationisbeingcollected.Principalresidentfishinthebasinincludegrayling,rainbowtrout,laketrout,whitefish,sucker,sculpin,burbotandDollyVarden.SincetheSusitnaisaglacialfedstreamthewatersaresiltladenduringthesummermonths.ThistendstorestrictsportfishingtoclearwatertributariesandtoareasintheSusitnanearthemouthofthesetributaries.IntheUpperSusitnaBasingraylingpopulationsoccuratthemouthsandintheuppersectionsofclearwatertributaries.BetweenDevilCanyonandtheOshetnaRiversmosttributariesaretoosteeptosupportsignificantfishpopulations.Manyterraceanduplandlakesintheareasupportlake.troutandgraylingpopulations.(ii)BigGameTheprojectareaisknowntosupportspeciesofcaribou,moose,bear,wolves,wolverineandDallsheep.-Caribou:TheNelchinacaribouherdwhichoccupiesarangeofabout20,000squaremilesinsouthcentralAlaskahasbeenimportantto7-9 huntersbecauseofitssizeandproximitytopopulationcenters.Theherdhasbeenstudiedcontinuouslysince1948.Thepopulationdeclinedfromahi9hofabout71,000in1962toalowofbetween6,500and8,100animalsin1972.FromOctober1980estimates,theNelchinacaribouherdcontainedapproximately18,500animalscomposedof49percentcows,30percentbullsand21percentcalves.Duringthelatewinterof1980,thecaribouweredistributedintheChistochina-GakonaRiverdrainages,thewesternfoothillsoftheAlphabetHillsandthelakelouiseFlat.Thereweretwomainmigra-tionroutestothenorthernfoothillsoftheTalkeetnaMountains.ThefirstroutewasacrossthelakelouiseFlattothecalvingareaviathelowerOshetnaRiver,andthesecondwasacrosstheSusitnaRiverintheareafromDeadmanCreektothe"bigbend"oftheSusitna.CalvingoccurredbetweentheOshetnaRiverandKosinaCreekbetweenthe3,000to4,500feetelevations.Themainsummer-ingconcentrationofcaribouoccurredinthenorthernandeasternslopesoftheTalkeetnaMountainsbetweenTsisiCreekandCrookedCreek,primarilybetween4,000and6,000feet.MostcaribouwerelocatedonthelakelouiseFlatduringtherut.Duringearlywintertheherdwassplitintwogroups.OnegroupwaslocatedintheSlideMountain-littleNelchinaRiverareaandtheotherwasspreadfromtheChistochinaRiverwesttotheGakonaRiverthroughtheAlphabetHillstotheMaclarenRiver.Itappearsthatatleasttwosmallsubherdswithseparatecalvingareasalsoexisted,oneintheupperTalkeetnaRiverandoneintheupperNenana-Susitnadrainages.Theproposedimpoundmentswouldinundateaverysmallportionofapparentlowqualitycaribouhabitat.Concernhasbeenexpressedthattheimpoundmentsandassociateddevelopmentmightserveasbarrierstocariboumovement,increasemortality,decreaseuseofnearbyareasandtendtoisolatesubherds.-Moose:MoosearedistributedthroughouttheUpperSusitnaBasin.PopulationestimatesforNovember1980incensusareas6,7and14(Fig.7.5)wereapproximately$30and3,000respectively.WinterdistributionsareshownonFigure7.5.Studiestodatesuggestthattheareastobeinundatedareutilizedbymooseprimarilyduringthewinterandspring.Thelossoftheirhabitatcouldreducethemoosepopulationforthearea.Theareasdonotappeartobeimportantforcalvingorbreedingpurposes,how-evertheydoprovideawinterrangethatcouldbecriticalduringseverewinters.Inadditiontodirectlosses,displacedmoosecouldcreatealowercapacityfortheanimalsinsurroundingareas.-Bear:Blackbearandbrownbearpopulationsinthevicinityoftheproposedreservoirsappeartobehealthyandproductive.BrownbearsareubiquitousthroughoutthestudyareawhileblackbearsappearlargelyconfinedtoafingerofforestedhabitatalongtheSusitnaRiver.7-10 Theproposedimpoundmentsarelikelytohavelittleimpactontheavailabilityofadequatebrownbeardensites,howevertheextentandutilityofhabitatsutilizedinthespringfollowingemergencefromthedensmaybereduced.Thenumberofbrownbearsinthe3,500squaremilestudyareaisapproximately70.BlackbeardistributionappearstobelargelyconfinedtoorneartheforestsfoundinthevicinityoftheSusitnaRiverandthemajortributaries.Utilizationoftheforesthabitatappearsmostprevalentintheearlyspring.Inthelatesummerblackbearstendtomoveintothemoreopenshrublandsadjacenttothespruceforestduetothegreaterprevalenceofberriesintheseareas.MostoftheknownactivedensintheDevilCanYonareawillnotbeinundatedalthoughseveralknowndenswillbeinundatedbytheWatanaResevoir.-Wolf:FiveknownandfourtofivesuspectedwolfpackshavebeenidentifiedintheUpperSusitnaBasin(Fig.7.6)(3).Territorysizesforthefivestudiedwolfpacksaveraged452to821squaremiles.Knownwolfterritoriesareeventuallynon-overlappingduringanyparticularyear.Aminimumof40wolveswereknowntoinhabitthestudyareainthespringof1980.Byfallthepackshadincreasedtoanestimated77wolves.Impactsonwolvescouldoccurindirectlyduetoreductioninpreydensity,particularlymoose.Temporaryincreasescouldoccurintheprojectareaduetodisplacementofpreyfromtheimpoundmentareas.Directinundationofdenandrendezvoussitesmaydecreasewolfden-sities.Potentialforincreasedhuntingandtrappingpressurecouldalsoacttoincreasewolfmortality.-Wolverine:Wolverinesoccurthroughoutthestudyareaalthoughtheyshowapreferencetowardsuplandshrubhabitatsonsoutherlyandwesterlyslopes.Potentialimpactswouldrelatetodirectlossofhabitat,constructiondisturbanceandincreasedcompetitionforprey.-DallSheep:DallsheepareknowntooccupyallportionsoftheUpperSusitnaRiverBasinwhichcontainsextensiveareasofhabitatabove4,000feetelevation.ThreesuchareasintheproximityoftheprojectareaincludethePortage-TsusenaCreekdrainages,theWatanaCreekHillsandMountWatana.SinceDallsheepareusuallyfoundatelevationsabove3,000feet,impactswilllikelyberestrictedtopotentialindirectdisturbancefromconstructionactivitiesandaccess.(iii)FurbearersFurbearersintheUpperSusitnaBasinincluderedfox,coyote,lynx,mink,pinemarten,riverotter,short-tailedweasel,leastweasel,muskratandbeaver.Directinnundation,constructionactivitiesandaccesscanbeexpectedtogenerallyhaveminimalimpactonthesespecies.7-11 (iv)BirdsandNon-GameMammalsOnehundredandfifteenspeciesofbirdswererecordedinthestudyareaduringthe1980fieldseason,themostabundantbeingScaupandCommonRedpoll.Tenactiveraptor/ravennestshavebeenrecordedandofthese,twoBaldEaglenestsandatleastfourGoldenEaglenestswouldbefloodedbytheproposedreservoirs,aswouldaboutthreecurrentlyinactiveraptor/ravennestsites.Preliminaryobservationsindicatealowpopulaitonofwaterbirdsonthelakesintheregion;however,TrumpeterSwansnestedonanumberoflakesbetweentheOshetnaandTyoneRivers.FloodingwoulddestroyalargepercentageoftheripariancliffhabitatandforesthabitatsupriverofDevilCanyondam.Raptorsandravensusingthecliffscouldbeexpectedtofindalternatenestingsitesinthesurroundingmountains,andtheforestinhabitantsarerelativelycommonbreedersinforestsinadjacentregions.Lesseramountsoflowlandmeadowsandoffluviatileshorelinesandalluvia,eachimportanttoafewspecies,willalsobelost.Noneofthewaterbodiesthatappeartobeimportanttowaterfowlwillbeflooded,norwilltheimportantpreyspeciesoftheuplandtundraareasbeaffected.Impactsofothertypesofhabitatalterationwilldependonthetype ofalteration.Potentialimpactscanbelessenedthroughavoidanceofsensitiveareas.Thirteensmallmammalspecieswerefoundduring1980,andthepresenceofthreeotherswassuspected.Duringthefallsurvey,red-backedvolesandmaskedshrewswerethemostabundantspeciestrapped;andthese,plustheduskyshrew,appearedtobehabitatgeneralists,occupyingawiderangeofvegetationtypes.Meadowvolesandpygmyshrewswereleastabundantandthemostrestrictedintheirhabitatuse,theformeroccurringonly inmeadowsandthelatterinforests.(b)VegetationTheUpperSusitnaRiverBasinislocatedinthePacificMountainphysio-graphicdivisioninsouthcentralAlaska(JointFederal-StateLandUsePlanningCommissionforAlaska1973).TheSusitnaRiverdrainspartsoftheAlaskaRangeonthenorthandpartsoftheTalkeetnaMountainsonthesouth.Manyareasalongtheeast-westportionoftheriver,betweentheconfluencesofPortageCreekandtheOshetnaRiver,aresteepandcoveredwithconifer,deciduousandmixedconifer,anddeciduousforests.Flatbenchesoccuratthetopsofthesebanksandusuallycontainlowshruborwoodlandconifercommunities.Lowmountainsrisefromthesebenchesandcontainsedge-grasstundraandmatandcushiontundra.ThesoutheasternportionofthestudyareabetweentheSusitnaRiverandLakeLouiseischaracterizedbyextensiveflatareascoveredwithlowshrublandandwoodlandconifercommunities.Theseareoftenintermixedanddifficulttodistinguishinthefieldoronaerialphotographsbecauseofintergradations.TheareabetweentheMaclarenRiverandtheDenaliHighwayalongtheSusitnaRiveriscoveredwithwoodlandandopensprucestands.Farthereast,theareahasmorelowshrublandcover.The7-12 ClearMountainsnorthoftheDenaliHighwayhaveextensivetundravegetation.ThefloodplainoftheSusitnaRivernorthoftheDenaliHighwayhaswoodlandspruceandwillowstands.TheAlaskaRangecontainsmostofthepermanentsnowfieldsandglaciersinthestudyarea.Ifproposedmaximumpoolelevationsarerequired,theDevilCanyon(mappedatthe1500ftelevation)andWatana(mappedatthe2200ftelevation)reservoirswillinundateapproximately3603and15,885haofarearespectively;2753and13,669ha,respectively,arevegetated(Table7.7).Atotalof18,109haofvegetationwillbelostifallborrowareas(outsidetheimpoundmentareas)arealsototallyutilized.Borrowsitesmayeventuallyberevegetated,however.The18,109haofimpactedvegetationrepresentsroughly1.2percentofthetotalvegetatedareaintheUpperSusitnaRiverBasin.Assumingmaximumimpactintheimpoundmentandborrowareas,thevegetation/habitattypeswhichwillbelost(andtheapparentpercenteachisofthetotalavailableintheentirebasin)arepresentedinTable7.7.Problemscreatedbycomparingmapsoftwodifferentscalesresultedinapparentpercentagesofoverlapwhicharehighlyinflatedforthecomparisonofbirchforestsintheimpactareaswiththatoftheiravailabilityoftheoverallbasin.However,itcansafelybesaidthatbirchforestswillbesubstantiallyimpactedbytheproject,relativelymoresothananyothervegetation/habitattype.Theonlyothertypeswhichwouldrecieverelativelysubstantialimpactareopenandclosedconifer-deciduousforestsandopenandclosedbalsampoplarstands.Theaccessroadorrailroadwilldestroyanadditional150to300haofvegetation,dependingoftherouteselected,andassumingaccessisfromonedirectiononlyanda30mwideroadbedisutilized.Three-hundredhectaresisroughlyequalto0.02percentofthevegetationintheentirebasin.Theprimaryvegetationtypestobeaffectedarematandcushiontundra,sedge-grasstundra,birchshrublandandwoodlandspruce.Preliminaryobservationsindicatethattheimpoundmentsandalternativeroutesarewellbelowtheelevationwherepotentialthreatenedorendangeredspeciesmightoccur.c)CulturalResourcesThearcheologicalstudypresentlybeingconductedaspartoftheSusitnaHydroelectricprogramistheonlyintensivearcheologicalsurveytohavebeenconductedintheUpperSusitnaBasin.ThearcheologicaldatagatheredfromthisstudywillgreatlyaddinformationandunderstandingofprehistoricnativepopulationsincentralAlaska.7-13Iii The1980archeologicalreconnaissance,intheSusitnaHydroelectricProjectarea,locatedanddocumented40prehistoricsitesandonehistoricsite.Itisexpectedthatcontinuedreconnaissancesurveysin1981willlocateadditionalsites.SitesarealsodocumentedadjacenttothestudyareanearStephanLake,FogLakes,LakesSusitna,TyoneandLouise,andalongtheTyoneRiver.Determinationsofsignificanceofsiteswillbebasedontheintensivetestingdatacollectedduringthesummerof1981andnationalregistercriteriawhichdetermineeligibilityforthenationalregisterofhistoricplaces.~Geologicalstudiesgenerateddatathatwereusedinselectingarcheologicalsurveylocals.DataconcerningsurficialgeologicaldepositsandglacialeventsofthelastglaciationwerecompiledandprovidedlimitingdatesfortheearliestpossiblehumanoccupationoftheUpperSusitnaValley.Thisisthefirsttimethistypeofstudyhasbeendoneinthisarea.PaleontologicalstudieswereconductedthatidentifiedtheWatanaCreekareaasatertiarybasinwithafossilbearingdeposit.Atertiarybasinisuniqueintheregiontherebymakingthisbasinasignificantsiteforobtainingdataonregionaltertiaryfloraandfauna.Impactsonculturalresourceswillvaryinrelationtothetypeofactivitiesthatoccuronornearthem.WithintheDevilCanyon,WatanaDamstudyareaitisexpectedthatwiththedevelopmentofthisschemeapproximatelyhalfoftheculturalresourcesiteswouldreceivedirectimpactandtheotherhalfindirectimpacts.TheWatanaCreektertiarybasinwouldalsobeinundated.SincefewreconnaissancesurveyshavebeenconductedoutsidetheDevilCanyon/WatanaDamstudyarea,theprecisenumberofsitesthatwouldbeimpactedbyaHighDevilCanyon/VeeSchemecannotbelistedatthistime.However,preliminarydataanalysesindicateaclearnumberofarcheologicalsitestowardtheeastendofthestudyarea.Inaddition,thereisahighpotentialformanymoresitesalongthelakes,streamsandriversinthiseasterlyregionoftheUpperSusitnaRiverBasin.AdditionalsitescouldbeexpectednearcariboucrossingsoftheOshetnaRiver.Insummary,apreliminaryassessmentofavailableinformationsuggeststhatthereperhapscouldbeagreaternumberofarcheologicalsitesassociatedwithHighDevilCanyon/VeeSchemethantheWatana/DevilCanyonScheme.(d)SocioeconomicsAspartoftheSusitnaHydroelectricprogramasocioeconomicprogramhasbeenimplementedtoidentifythesocioeconomicfactorsthatwillbeaffectedandtodeterm<netheextenttowhichtheywillbeimpacted.Theresultsofthisstudywillalsoprovideinputintotheselectionofthetypeandlocationofcertainprojectfacilities.(i)PopulationTheSouthcentralRailbeltareaofAlaskacontainstheState'stwolargestpopulationcenters,AnchorageandFairbanks.Preliminary1980censusfiguresindicatetheRailbeltcontained280,511people,717-14 percentofthestatepopulationof400,331.Thestatepopulationhasincreasedapproximately30percentsince1970.TheMat-Suborrowareahada1980populationof17,938andValdez-Cordova-8,546.HousingintheMat-SuBurrowisprimarilysinglefamilyyearroundunits.VacancyratesforMat-SuBorough,Fairbanks,andAnchoragewere5.5%(289units)9.1%(1,072units)and10.2%(5,729units)respectively.Inadditiontoyearroundunits,Mat-SuBoroughhas1,141recreationalunits.(ii)EconomicsBothAnchorageandFairbanksareregionaleconomiccentersfortheSouthcentralRailbeltarea.Government,trade,andservicescomprisethemajor'portionofthearea'stotalemployment.Constructionandtransportationarealsoimportant.Makingrelativelylesssignificantcontributionsarethefinancing,mining,andmanufacturingindustries,whileagriculture,forestry,andfisheriescontributeevenless.Aftergovernment,thetwogroupshavingthelargestemploymentaretradeandservices.TheirimportanceassourcesofemploymentfortheRailbeltarearesidentsisafurthermanifestationoftheregion'stworelativelyconcentratedpopulationcentersandofthehighdegreeofeconomicdiversity,aswellaslevelsofdemandforgoodsandservices,whicharesubstantiallyhigherthaninmostotherpartsofAlaska.TheimportanceofconstructionislargelyduetothehighlevelofexpansionexperiencedbytheAnchorageandFairbanksareassince1968.Thisgrowthwaspartlyattributabletothetrans-Alaskapipelineproject.Considerationofadditionalnaturalresourceexploitationprojectsiscontinuingtoencourageincreasedconstructionactivities.Highlevelsofemploymentintheregion'stransportationindustryreflectthepositionsofAnchorageandFairbanksasmajortransporta-tioncenters,notonlyfortheSouthcentralRailbeltareabutfortherestoftheStateaswell.ThePortofAnchoragehandlesmostofthewaterbornefreightmovingintosouthcentralandnorthernAlaska.Internationa'lairportsatAnchorageandFairbanksserveashubsforcommercialairtrafficthroughoutAlaskaandareimportantstopoversformajorinternationalaircarriers.Anchoragealsoservesasthetransferpointforgoodsbroughtintheareabyairandwater,whicharethendistributedbyairtransport,truckorbyAlaskaRailroadtomoreremoteareas.Valdezisthestateslargestporthandlinganannualtonnageof60milliontons.Ninety-sevenpercentofthisinvolvestheshipmentofcrudepetroleumfromthepipeline.TheportsofAnchorageandValdezhandle2.2milliontonsand0.4milliontonsrespectively.Althoughexertingrelativelylittledirectimpactontotalemployment,mining,finance,insurance,andrealestateplayimportantrolesintermsofthesecondaryemploymenttheygenerateintheregion.7-15 7-16ThetouristindustryplansanincreasinglyimportantroleintheeconomyofAlaska.In1977approximately504,000peoplevisitedAlaskaspendingatotalof$374million.(e)Transportation(iii)Air.InadditiontomajorairlineswithinAlaska,therearenumeroussmallcommericaloperatorsplusthehighestpercapitaratioofprivateaircraftinthenation.ManysmallremotelandingstripsarescatteredthroughouttheSusitnabasin,andfloatplanesutilizemanylakesandstreamstoferryfreightandpassengerstotheremoteback-countryareas.InmanyareasoftheState,theonlyaccessisprovidedbytheairplane.TheonlyroadaccessthroughtheupperSusitnabasinisthe135-milegravelDenaliHighwaybetweenPaxsonontheRichardsonHighwayandCantwellontheParksHighway,andthe20-milegravelroadfromtheGlennHighwaytoLakeLouise.TheDenaliHighwayisnotopenforuseduringthewintermonths.Rail.TheAlaskaRailroadrunsfromSewardontheGulfofAlaska,pastAnchorage,uptheSusitnaValley,pastMountMcKinleyNationalPark,anddowntoFairbanksontheTananaRiver,adistanceof483miles.TheFederallyconstructedandoperatedAlaskaRailroadwasbuiltbetween1914and1923.Annualtrafficvolumevariesbetween1.8and2.3milliontons.Coalandgravelaccountfor7510ofthis.Thesystemisoperatingatonly20%ofitscapacity.Roads.PavedroadsintheRailbeltareainclude:the227-mileSterling-SewardHighwaybetweenHomerandAnchorage, witha27-milesidespurtoSeward;thenewly-constructed358-mileParksHighwaybetweenAnchorageandFairbanks;a205-milesectionoftheAlaskaHighwaythatconnectsTokJunctionwithFairbanks;the328-mileGlennHighwayconnectingAnchoragewithTokJunction;andthe226-mileRichardsonHighwayfromValdez,onPrinceWilliamSound,toitsjunctionwiththeAlaskaHighwayatDeltaJunction,97milessoutheastofFairbanks.(i )(ii)MostagriculturalactivitiesintheSouthcentralRailbeltareatakeplaceintheMatanuska,Susitna,andTananaValleys.ThepotentialforagriculturalintheseareasofAlaskaisconsideredfavorable,althoughdevelopmentoftheindustryhasnotbeenextensive.Commercialfisheriesactivityistheoldestcash-basedindustryofmajorimportancewithintheregion.TheindustryhaschangedsUbstantiallyduringthepast20yearsandcontinuestobemodifiedasaresultofbothbiologicandeconomicstimuli.Thesalmonindustryhasalwaysbeenamajorcomponentoftheindustryintermsofvolumeandvalue.Since1955,thekingcrab,shrimp,andTannercrabfisherieshaveundergonemajordevelopment,andhalibutlandingshaveincreasedsUbstantiallyinrecentyears.Thetotalwholesalevalueofcommercialfishandshell-fishforthedomesticfisheryofAlaskain1979wasjustover$1.2billionincludingacatchof459millionpoundsofsalmonwithawholesalevalueofjustover$700million. (iv)OtherFormsofTransportation.ATVsandothertypesofoff-roadvehiclesprovidetransportationintoareasintheupperSusitnabasinwheretherearenodevelopedroads.Severaldevelopedtrailsareshownonmapsoftheupperbasin.TrailsareutilizedbyATVs,trailbikes,hikers,horsebackriders,andwintertravelers.Shallow-draftriverboats,smallboats,canoes,rubberrafts,andkayaksutilizesectionsoftheupperSusitnaRiver,afewtributarystreams,LakeLouise,andsomeoftheotherlakesforrecreationpurposes.Exceptforthesefewareas,boatinguseispracticallynonexistentwithinmuchoftheupperbasin.LandUseExistinglanduseintheSusitnaProjectareaischaracterizedbybroadexpansesofopenwildernessareas.Thoseareaswheredevelopmenthasoccurredoftenincludedsmallclustersofseveralcabinsorotherresidences.Therearealsomanysinglecabinsettlementsthroughoutthebasin.Mostoftheexistingstructuresarerelatedtohistoricaldevelopmentoftheareainvolvinginitially,hunting,mining,andtrappingandlaterguidingactivitiesassociatedwithhuntingandtoalesserextentfishing.Todaythereareafewlodgesmostlyusedbyhuntersandotherrecrea-tionalists.Manylakesintheareaalsoincludedsmallclustersofprivateyearroundorrecreationalcabins.Thereareapprximately109structureswithin18milesoftheSusitnaRiverbetweenGoldCreekandtheTyoneRiver.Theseincluded4lodgesinvolvingsome21structures.Asignificantconcentrationofresidences,cabinsorotherstructuresarefoundneartheOtterlakearea,PortageCreek,HighLake,GoldCreek,ChunilaCreek,StephanLake,FogLake,TsusenaLake,WatanaLake,ClarenceLakeandBigLake.Perhapsthemostsignificantuseactivityforthepast40yearshasbeenthestudyoftheSusitnaRiverforpotentialhydrodevelopment.Hunting,boating,andotherformsofrecreationarealsoimportantuses.Therearenumeroustrailsthroughoutthebasinusedbydogsled,snowmobileandATV's.Airuseissignificantformanylakesprovidinglandingareasforplanesonfloats.Therehasbeenlittlelandmanagementactivityforthearea.However,FederalandStateagencies,nativecorporationsandtheprivatesectorhavebeeninvolvedheavilyintheselectionandtransferoflandownershipundertheAlaskaStatehoodandtheAlaskaNativeClaimssettlementAct.Mostofthelandsintheprojectareaandonthesouthsideoftheriverhavebeenselectedbythenativecorporation.LandstothenortharegenerallyfederalandmanagedbyBLM.7-17 TA8LE 7.1 -SUMMARY OF CLIMATOLOGICAL DATA MEAN MONTHLY PRECIPITATION IN INCHES STATIDN JAN FE8 MAR APR MAY JUNE J U L Y AUG SEPT OCT NOV DEC ANNUAL Anchoraae 0.84 0.56 0.56 0.56 0 . 5 9 1.07 2.07 2 . 3 2 2 . 3 7 1.43 1 . 0 2 1.07 8io Delta 0.36 0.27 0.33 0.31 0.94 2.20 2 . 4 9 1.92 1.23 0.56 0.41 0.42 11.44 Fairbanks 0.60 0.53 0.48 0 . 3 3 0 . 6 5 1.42 1.90 2.19 1.08 0.73 0.66 0.65 11.22 Gulkana 0.58 0.47 0.34 0 . 2 2 0.63 1.34 1 . 8 4 1.58 1.72 0.88 0.75 0 . 7 6 11 .11 Matanuska Agr. Exp.Station 0.79 0.63 0.52 0 . 6 2 0.75 1.61 2.40 2 . 6 2 2.31 1.39 0.93 0.93 15.49 McKinley Park 0.68 0.61 0.60 0.38 0.82 2.51 3.25 2.48 1.43 0.42 0.90 0 . 9 6 15.54 Summit WSO 0.89 1.19 0.86 0.72 0.60 2.18 2.97 3.09 2.56 1.57 1 . 2 9 1.11 19.03 Talkeetna 1.63 1.79 1.54 1 . 1 2 1.46 2.17 3.48 4.89 4.52 2.54 1.79 1.71 28.64 MEAN MONTHLY TEMPERATURES -.I I ~ ():) Anchoraae 11.8 17.8 23.7 35.3 46.2 54.6 5 7 . 9 5 5 . 9 48.1 34.8 21.1 13.0 8io Delta -4.9 4.3 12.3 29.4 46.3 57.1 59.4 5 4 . 8 43.6 25.2 6.9 -4.2 27.5 Fairbanks -11.9 -2.5 9.5 28.9 47.3 59.0 60.7 55.4 44.4 25.2 2.8 -10.4 25.7 Gulkana -7.3 3.9 14.5 30.2 43.8 54.2 56.9 53.2 43.6 26.8 6.1 -5.1 26.8 Matan\Jska Agr. EXD.Station 9.9 17.8 23.6 36.2 46.8 54.8 57.8 5 5 . 3 47.6 33.8 20.3 12.5 34.7 McKinley Park -2.7 4.8 11.5 26.4 40.8 51.5 54.2 5 0 . 2 40.8 23.0 8.9 -0.1 25.8 Summit WSO -0.6 5.5 9.7 23.5 37.5 48.7 52.1 48.7 39.6 23.0 9.8 3.0 25.0 Talkeetna 9.4 15.3 20.0 32.6 44.7 55.0 57.9 5 4 . 6 46.1 32.1 17.5 9.0 32.8 ~: Reference 4 TABLE7.2-RECOROEOAIRTEMPERATURESATTALKEETNAANDSUMMITINofSTAlIONtalkeetnaSumm1tDailyDailyMonthlyDaily DailyMonthlyMonthMax.Min.AverageMax.Min.AverageJan19.1-0.49.45.7-6.8-0.6Feb25.84.715.312.5-1.45.5Mar32.87.120.018.01.39.7Apr44.021.232.632.514.423.5May56.133.244.745.629.337.5June65.744.355.052.439.848.7Jul67.548.257.960.243.452.1Aug64.145.054.656.041.248.7Sept55.636.646.146.932.239.6Oct40.623.632.129.416.523.0Nov26.18.817.515.64.09.8Dec18.0-0.19.09.2-3.33.0IAnnualAverage32.825.0JJ'ijIIIIII,,7-19 TABLE7.3-MAXIMUMRECORDEDICETHICKNESSONTHESUSITNARIVERLocationSusitnaRiveratGoldCreekSusitnaRiveratCantwellTalkeetnaRiveratTalkeetnaChulitnaRiveratTalkeetnaMaclarenRiveratPaxson7-20MaximumIceThickness(Feet)5.75.33.35.35.2 TABLE7.4-AVERAGEANNUALANDMONTHLYFLOWATGAGEINTHESUSiTNABASINSTATION(USGSReferenceNumberSusitnaRiverSusitnaRiverSusitnaRiverMaclarenRiveratGoldCreekNearCantwellNearDenaliNearPaxsonMONTH(2920)(2915)(2910) (2912)%Mean(cfs)%Mean(cfs)%Mean(cfs)%Mean(cfs)JANUARY1,43BB24245190FEBRUARY1,21372220478MARCH1,085169218771APRIL1,3391B531233182MAY1213,400107,70162,0637845JUNE2428,1502619,330237,431252,926JULY2123,9902316,890299,428273,171AUGUST1921,9502014,660247,813222,557,SEPTEMBER1213,770107,800103,343101,184::1OCTOBER55,58043,03331,13B3407\1"INOVEMBER22,43521,4492502168'iDECEMBER21,7481998318111ANNUAL-cfs9,6106,3002,7209757-21 TABLE7.5-FLOODPEAKSATSELECTEDGAGINGSTATIONSONTHESUSITNARIVEROpenWaterAnnualFloodPeaks-efaSeasonDrainageMean50YearFloodStation(USGSNo.)Area-mile2Annual1:100yr1:10,000yrPeaks-efsGoldCreekGage(2920)6,16053,00011B,OOO185,000106,000Cantwe11Gage(2915)4,14033,7006B,OOO118,00061,700DenaliGage(2910)95017,80043,60063,00036,6007-22 TABLE7.6-SUSPENDEDSEDIMENTTRANSPORTStationSusitnaatGoldCreekSusitnanearCantwellSusitnanearDenaliMaclarennearPaxson7-23SedimentTransport(Tons/year)8,734,0005,129,0005,243,000614,000InitialUnitWeight(Lb/ft3)65.370.670.468.6 TABLE 7.7 -DIFFERENT VEGETATION TYPES FOUND IN THE SUSITNA BASIN Hectares of vegetation types to be impacted compared with total hectares of those types. Impoundments Devil Canyon Watana A c Borrow Areas o F H Upper Susitna River Basin 2 3 100 (2.07)6 (0.12)1 (0.02) 78 (0.12) 580 (0.45)1B (0.01)23 (0.22)B (0.01) 474 (1.41)18 (0.05)92 (0.27)73 (0.22) 55 (0.52) 785 (0.15)101 (0.02)113 (0.02)109 (0.02)55 (0.01) 47 (0.22)3 (0.01)1 (+) 2106 (14.35)10 (0.07)6 (0.04) 63 (0.06)1 (+) 15B39 (0.97)500 (0.03)322 (0.03)228 (0.01)71 (+) ..... I N .." Woodland spruce Open spruce Open birch Closed birch Open conifer-deciduous Closed conifer-deciduous Open balsam poplar Closed balsam poplar Wet sedge grass and cushion tundra Tall shrub Birch shrub Willow Low mixed shrub Lakes Rivers Rock Total Areas NOTES: 162 (0.09)1 B62 (0.73) 73 (0.73) 4702 300 (1.2B) 75B (4.75) 73 10 3 12 (0.25) 19 (0.01) 58 (0.17) 16 (0.015) 6 (+) 1 (+) B35 (5.69) 14 (0.01) 3603 (0.22) 4766 (2.53)228 (0.12) 3854 (3.24)48 (0.04) 31B (2.85) 491 2 1329 (5.68) 869 (5.44) 77 (0.04) 7 (0.01) 15 (0.01) 12 19 (O.OB) 2 (0.01) 9 (0.04) 227 (0.12) 125 (0.11) 94 (0.40) 7 (0.07) 46 (0.01) 499 (0.03) 188,391 118,873 968 323 23,387 15,969 4,B39 65 001 3 4, 129,035 33,549 10,645 471,461 21,162 14,67B 113,712 1,211,992 (1) (2) (3) (4) Numbers in parentheses are the percent of the vegetation as found in the entire Upper Susitna Basin. Hectares of closed birch are apparently greater in the impact areas (mapped at a scale of 1:24,000)than for the entire basin (mapped at a scale of 1:2)0,000),because the basin was mapped at a much smaller scale,and many of the closed birch stands did not appear at that scale. Balsam poplar stands were too small to be mapped at the scale of which the Upper Susitna River Basin was mapped. Total hectares of mat and cushion tundra are much greater than this,but many hectares were mapped as a complex with sedge-grass tundra. [iJ PAXSON!::, GULKANA\} FIGURE 7.1 ~ '\ J, l '''\ \ I ~'-""'\.,..~ \ ~Ff!!I' SUSITNA :Dr (NO DEFINITEj< LOCATION)G ~i3" ~ TYONE &DAMSITE CANTWELL •STREAMGAGE SUMMIT \l CLIMATE TAt.K£ETNA RIVER-- -~~B~EVIL ~ CANYON HIGH ~f"-\........'--,I"\._""--" GOLO CREEK \1, ""-, l.. \ (" ';» <'\ \ '\ DATA COLLECTION STATIONS ~ 5 0 5 15 ~I SCALE IN MILES ---J I Nen "~,~,._---"-"",-,,,,,,,,,-...""'",,,,,"""'''''''''"'''''''''''"""",-",,_.""""'''''' "'''''''''''''''''_.'''''''''''''''''""''''''''''""'''''''''''"'''''""-;:;;,:::"~==::;:;-~~-";::':-"''''~,,7,,:;:::;;,::~'''''-;;:~:~--;;:,,-:;;:=,,,,,;:,;:::,;",~~',,-""~,,-'''''' SUSITNARIVERDEVILWATANACANYONSITESITEGOLDCREEKPARKSHIGHWAYBRIDGEGAGINGSTATIONSUSITNAGAGINGSTATIONCOOKINLETAVERAGEANNUALFLOWDISTRIBUTIONWITHINTHESUSITNARIVERBASINFIGURE7.27-26 50,000 LEGEND WETTEST YEAR -1962 AVERAGE YEAR 0 40,000 Z 0 () W Cf) a:::w '-J I 0.. I l- N 30,000 '-J W W LL () CD :::> ()....... ~20,000 0 ...J LL ~ <! Wa::: I- Cf) 10,000 o k.:.!:.!:.6.f.&.&f.t..(l.?~.d I ((.1./..(I:;;;;;;;;;;;;;;;;;;;;;;;;;;;II~~~~~I:::~~~~~~~II:~:~:~:::~:~~~~~~:::::::::I::~~j~~:::::::::::j~j~jI:I~::::::~~~~~:~::::~~~~~:~:::riiii!i!iiiiiiiiiiiiiiiiiiiliii!i!iiiiiiiiiiiiiiiiiiiilkN{&~~!f";{{.f{1 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT MONTHLY AVERAGE FLOWS IN THE SUSITNA RIVER AT GOLD CREEK NOV DEC FIGURE 7.3 [ii] 8!ONUPTHROWNAMPHIBOLITEETHONUPTHROWNSIDE,DASHEDWHEREINFERREDOTTEDW""R4WfJ\7\l\i\1"J~6.6.6.~TRIASSICj:""ZA""'~;l1<:-1>A.>,I---_-..IPALEOZOICTHRUSTFAULT-........--"9'''INTENSESHEARING••°7°•••rr::::;••ARGILLITEANDLITHICGRAYWACKEUNDIVIDEDGRANITICROCKSMAFICINTRUSIVESSCHIST,MIGMATITE,GRANITICROCKSLEGENDGRANODIORITE,QUARTZDIORITE,TRONDHJEMITEUNDIFFERENTIATEDVOLCANICS8SHALLOWINTRUSIVESUNDIFFERENTIATEDSURFICIALDEPOSITSGRANODIORITE,BIOTITE-HORNBLENDEGRANODIORITE,BIOTITEGRANODIORITEJURASSICITJTIlITDfF"-r'""l1+ +ofI.-.....~n-;-.s":::'J~~.<j:~lCENOZOICQUATERNARY,---,:I""-..IMESOZOICCRETACEOUSE-=::'-::-=-=-JL-_-_-_-_-Jt..-::..-_-_-:..-.,JREGIONALGEOLOGY....ModifiedfromCsejtey,et01,1978>-a::<{oz:::::>oCO::r:....a::+------f-~++I_I+m..J,C=---_:;,.f.+HlL_---+-.......::==:........:t,t::::rPL-~~_+---:------____i~ wU)oo~w>I-<t...JW0::U)IJJI-U)ZWoI.L.o..0::WCO~W>ozo00en'"liJ.J~ZlJJ.J«(j'"oo,.,>-l-enZWo::I:(!)::I:>-l-enZWo:E:::>ow::23:o...J>-l-enZWo~enzwoo0::WN«w0::«(J):::>(J)zw()-.ozw(!)W...J7-29a.«::2zo~()o...J 10 0 10 30 I I I I SCALE IN MILES '-J 1 Wo tid' LOCATION MAP RIVER ...."'""../-.......J'-",;--\~) r III-( (I I'\.I '\I , I \ (\'1t1:': \...._, "...f'J(-' ,) ) -\, "".... \ l \ I I.. \......(r{QI::>~--------\r~--/)---J .....--'t/ "'--./.../ ® MODIFIED FROM REFERENCE ( WINTER DISTRIBUTION OF MOOSE -MARCH,1980 FIGURE 7.6 [iii] LEGEND: m WATANA PACK ~TYONE PACK mJ]J]]SUSITNA PACK ~TOLSON A PACK r--, I I SUSPECTED PACKL__...J ® 10 0 10 30 I I I I I SCALE IN MitES -......r/-.......:-'\,,..--\~} r I I I-((i;"\I '\ I "I \ I \'n~! \....,..\ ........rJ (oJ .> "t::fl "fll(" \./'\,..(',...,--\;.-_....,,-\"....,\.' '\,X'\...) V'"-\. ""'\..... \ R~l \ I (\ ""l I \ -{ \ I\l '")---J .....- ,-_/,.J' LOCATION MAP -..I I W....... LOCATION AND TERRITORIAL BOUNDARIES OF WOLF PACKS -1980 FIGURE 7.7 [II LISTOFREFERENCES(1)Gedney~L.andShapiro~L.~StructuralLineaments,SeismicityandGeologyoftheTalkeetnaMountainsArea,Alaska,U.S.ArmyCorpsofEngineers,1975.(2)Csejtey,B.Jr.,etal."ReconnaissanceGeologyMapandGeochronology,TalkeetnaMountainQuadrangle,NorthernPartofAnchorageQuadrangle,andSouthwestCornerofHealyQuadrangle,Alaska",U.S.GeologicalSurvey,OpenFileReport,78-558A.(3)AlaskaDepartmentof FishandGame,1980DraftAnnualReport.(4)U.S.DepartmentofCommerce,NationalOceanicandAtmosphericAdministration,EnvironmentalDataSection,LocalClimatologicalData.7-32 - Aspecifiedsequenceofimplementationofpowergen-erationsourcescapableofprovidingsufficientpowerandenergytosatisfyanelectricloadgrowthforecastforthe1980-2010periodintheRailbeltarea.Thissequencemayincludedifferenttypesofgenerationsourcessuchashydroelectricandcoal,gasoroil-firedthermal.ThesegenerationscenariosarerequiredforthecomparativeevaluationsofSusitnaBasingenerationversusalternativemethodsofgeneration.-AnindividualpotentialdamsiteintheSusitnaBasin,equivalentto"alternative"andreferredtointhegenericprocessas"candidate".- Aplanfordevelopingenergywithinthebasininvolv-ingoneormoredams,eachofspecifiedheight,andcorrespondingpowerplantsofspecifiedcapacity.Eachplanisidentifiedbyaplannumberandsubnumberindicatingthestagingsequencetobefollowedindevelopingthefullpotentialoftheplanoveraperiodoftime.Theseareequivalenttothe"plans"referredtoinAppendixA.BasinDevelopmentPlanDamSiteGenerationScenario8-1Asoutlinedinthedescriptionofthegenericplanformulationandselectionmethodology(AppendixA)fivebasicstepsarerequired.Theseessentiallycon-sistofdefiningtheobjectives,selectingcandidates,screening,formulationofdevelopmentplansandfinally,adetailedevaluationoftheplans.Theobjectivesofthestudiesoutlinedinthissectionareessentiallytwofold.-TerminologyInthedescriptionoftheplanningprocess,certainplancomponentsandprocess-esarefrequentlydiscussed.Itisappropriatethatthreeparticulartermsbeclearlydefined:8.2-PlanFormulationandSelectionMethodologyThissectionofthereportoutlinestheengineeringandplanningstudiescarriedoutasabasisforformulationofSusitnaBasindevelopmentplansandselectionthepreferredplan.Theselectionprocessusedisconsistentwiththegener-icplanformulationandselectionmethodologydiscussedinSection1.4andAppendixA.Therecommendedplan,theWatana/DevilCanyondamproject,iscom-paredtoalternativemethodsofgeneratingRailbeltenergyneedsincludingther-malandotherpotentialhydroelectricdevelopmentsoutsidetheSusitnaBasinonthebasisoftechnical,economic,environmentalandsocialaspects.8 -SUSITNABASINDEVELOPMENTSELECTION=~----------~~~-- ThefirstistodeterminetheoptimumSusitnaBasindevelopmentplan,andsecondistoundertakeapreliminaryassessmentofthefeasibilityoftheselectedplanbycomparisonwithalternativemethodsofgeneratingenergy.Studiescarriedouttomeetthefirstobjectivefollowtheprescribedmetologyandareoutlinedinthefollowingsubsections.Step2ofthemethodolwhichcallsfortheselectionofcandidatedamsites,isoutlinedinSection8.3.Step3,screening,isdiscussedin8.4while Subsection8.6dealswithStep4,planformulation.Thefinalstep,planevaluation,isdealtwithinSubsection8.6.Figure8.1illustratestheprocessandhighlightsthedatasourcesandtechniquesusedforplanformulationandevaluation.Throughoutthisplanningprocess,engineeringlayoutstudieswereconductedrefinethecostestimatesforpowerorwaterstoragedevelopmentatseveralsiteswithinthebasin(Section8.5).Astheybecameavailable,thesedatafedintothescreeningandplanformulationandevaluationstudies.ThesecondobjectiveissatisfiedbycomparinggenerationscenariosthatincltheselectedSusitnaBasindevelopmentplanwithalternativegenerationiosincludingall-thermalandamixofthermalplusalternativehydropowerdevelopments.TheselectionandscreeningofalternativehydropowerthermalunitsanddevelopmentsisdiscussedinSections6.4and6.5respectively.planformulationstepwhichinvolvesdevelopingthealternativegeneratingscenariosisoutlinedinSection8.7below.ThefinalevaluationoftheplisalsodiscussedinSection8.7.8.3-DamSiteSelectionInthepreviousSusitnaBasinstudiesdiscussedinSection4,twelvedamsiwereidentifiedintheupperportionofthebasin,i.e.upstreamfromGold(seeFigure4.1).Thesesitesarelistedbelow:-GoldCreek-Olson(alternativename:SusitnaII)-DevilCanyon-HighDevilCanyon(alternativename:SusitnaI)-DevilCreek-Watana-SusitnaIII-Vee-Maclaren8-2 -Denali-ButteCreek-TyoneFigure8.2showsalongitudinalprofileoftheSusitnaRiverandtypicalreser-voirlevelsassociatedwiththesesites.Figure8.3illustrateswhichsitesaremutuallyexclusive,i.e.thosewhichcannotbedevelopedjointlysincethedownstreamsitewouldinundatetheupstreamsite.Allrelevantdataconcerningdamtype,capitalcost,power,andenergyoutputwereassembledandaresummarizedinTable8.1.FortheDevilCanyon,HighDevilCanyon,Watana,SusitnaIII,Vee,MaclarenandDenalisitesconceptualengineeringlayoutswereproducedandthecapitalcostestimatedbasedoncalculatedquantitiesandunitrates.Detailedanalyseswerealsoundertakentoassessthepowercapabilityandenergyyields.AttheGoldCreek,DevilCreek,Maclaren,ButteCreek,andTyonesites,nodetailedengineeringorenergystudieswereundertakenanddatafrompreviousstudieswereusedwithcapitalcostestimatesupdatedto1980levels.ApproximateestimatesofthepotentialaverageenergyyieldattheButteCreekandTyonesiteswereundertakentoassesstherelativeimportanceofthesesitesasenergyproducers.TheresultsinTable8.1showthatDevilCanyon,HighDevilCanyon,andvJatanaarethemosteconomiclargeenergyproducersinthebasin.SitessuchasVeeandSusitnaIIIaremediumenergyproducers,althoughslightlymorecostlythanthepreviouslymentioneddamsites.OthersitessuchasOlsonandGoldCreekarecompetitiveprovidedtheyhaveadditionalupstreamregulation.SitessuchasDenaliandMaclarenproducesubstantiallyhighercostenergythantheothersitesbutcanalsobeusedtoincreaseregulationofflowfordownstreamuse.Forcomparativepurposesthecapitalcostestimatesdevelopedinrecentpreviousstudies,updatedto1980values,arelistedalongsidethecostsdevelopedforthecurrentstudies(Table8.2).Theseresultsshowthatthecurrentestimatesaregenerallyslightlyhigherthanpreviousestimatesand,exceptinthecaseofVee,differencesarewithin15percent.AtDevilCanyoncurrenttotaldevelopmentcostsaresimilartothe1978COEes-timates.Althoughtheestimatesinvolvedifferentdamtypes,currentstudieshaveindicatedthatataconceptuallevelthecostofdevelopmentatthissiteisnotverysensitivetodamtype.TheresultsinTable8.2,therefore,indicaterelativeagreement.CostsdevelopedfortheHighDevilCanyondamsiteareveryclosewhilethoseatWatanaexceedpreviousestimatesbyabout15percent.AmajordifferenceoccursatVeewherecurrentestimatesexceedthosedevelopedbytheCOEby40percent.Alargeportionofthisdifferencecanbeascribedtothegreaterlevelofdetailincorporatedinthecurrentstudiesascomparedtothepreviousworkandthemoreextensivefoundationexcavationandtreatmentthathavebeenassumed.Thisadditionalfoundationworkisconsistentwithastandardsetofdesignassumptionsusedfordevelopingallthesitelayoutsreportedhere.Section8.4andAppendixDdiscusstheseaspectsinmoredetail.8-3 8.4-SiteScreeningTheobjectiveofthisscreeningexerciseistoeliminatesiteswhichwouldob-viouslynotfeaturetheinitialstagesofaSusitnaBasindevelopmentplanandwhich,therefore,donotrequireanyfurtherstudyatthisstage.Threebasicscreeningcriteriaareused;theseincludeenvironmental,alternativesites,energycontribution.(a)ScreeningCriteria(i)EnvironmentalThepotentialimpactontheenvironmentofareservoirlocatedateachofthesiteswasassessedandcatagorizedasbeingrelativelyunacceptable,significantormoderate.-UnacceptableSitesSitesinthiscategoryareclassifiedasunacceptablebecauseeittheirimpactontheenvironmentwouldbeextremelysevereorthereareobviouslybetteralternativesavailable.Underthecurrentcir~cumstances,itisexpectedthatitwouldnotbepossibletoobtainthenecessaryagencyapproval,permits,andlicensestodevelopthesesites.TheGoldCreekandOlsonsitesbothfallintothiscategory.AssalmonareknowntomigrateupPortageCreek,adevelopmentateitherofthesesiteswouldobstructthismigrationandinundatespawninggrounds.AvailableinformationindicatesthatsalmondonotmigratethroughDevilCanyontotheriverreachesbeyondbecauseofthesteepfallandhighflowvelocities.DevelopmentofthemidreachesoftheTyoneRiverwouldresultintheinundationofsensitivebiggameandwaterfowlareas,provideaccesstoalargeexpanseofwildernessarea,andcontributeonlyasmallamountofstorageandenergytoanySusitnadevelopment.Sincemoreacceptablealternativesareobviouslyavailable,theTyonesiteisalsoconsideredunacceptable.-SitesWithSignificantImpactBetweenDevilCanyonandtheOshetnaRivertheSusitnaRiveriscon-finedtoarelativelysteeprivervalley.UpstreamoftheOshetnaRiverthesurroundingtopographyflattensandanydevelopmentinthisareahasthepotentialoffloodinglargeareasevenforrela-tivelylowdams.AlthoughtheDenaliHighwayisrelativelycloseby,thisareaisnotasisolatedastheUpperTyoneRiverBasin.Itisstillverysensitiveintermsofpotentialimpactonbiggameandwaterfowl.ThesitesatButteCreek,Denali,Maclaren,and,toalesserextentVee,fitintothiscategory.8-4 -SitesWithModerateImpactSitesbetweenDevilCanyonandtheOshetnaRiverhavealowerpoten-tialenvironmentalimpact.ThesesitesincludetheDevilCanyon,HighDevilCanyon,DevilCreek,WatanaandSusitnasites,and,toalesserextent,theVeesite.(ii)AlternativeSitesSiteswhichareclosetoeachotherandcanberegardedasalternativedamlocationscanbetreatedasonesiteforprojectdefinitionstudypurposes.ThetwositeswhichfallintothiscategoryareDevilCreek,whichcanberegardedasanalternativetotheHighDevilCan-yonsite,andButteCreek,whichisanalternativetotheDenalisite.(iii)EnergyContributionThetotalSusitnaBasinPotentialhasbeenassessedat6700GWh.AsoutlinedonTable5.11,additionalfutureenergyrequirementsfortheperiod1980to2010areforecasttorangefrom2400to13,100GWh.Itwasthereforedecidedtolimittheminimumsizeofanypowerdevelop-mentintheSusitnaBasintoanaverageannualenergyproduction,intherangeof500to1000GWh.TheupstreamsitessuchasMaclaren,Denali,ButteCreek,andTyonedonotmeetthisminimumenergygenerationcriterion.(b)ScreeningProcessThescreeningprocessinvolvedeliminatingallsitesfallingintheun-acceptableenvironmentalimpactandalternativesitecategories.Thosefailingtomeettheenergycontributioncriteriawerealsoeliminatedun-lesstheyhavesomepotentialforupstream'regulation.Theresultsofthisprocessareasfollows:-The"unacceptablesite"environmentalcategoryeliminatedtheGoldCreek,Olson,andTyonesites.-ThealternativesitescategoryeliminatedtheDevilCreekandButteCreeksites.-Noadditionalsiteswereeliminatedforfailingtomeettheenergycon-tributioncriteria.TheremainingsitesupstreamfromVee,i.e.MaclarenandDenali,wereretainedtoensurethatfurtherstudybedirectedtowarddeterminingtheneedandviabilityofprovidingflowregulationintheheadwatersoftheSusitna.8.5-EngineeringLayoutandCostStudiesInordertoobtainamoreuniformandreliabledatabaseforstudyingthesevensitesremaining,itwasnecessarytodevelopengineeringlayoutsforthesesites8-5 andre-evaluatethecosts.Inaddition,itwasalsonecessarytostudystageddevelopmentsatseveralofthelargerdams.Thebasicobjectiveoftheselayoutstudiesistoestablishauniformandcon-sistentdevelopmentcostforeachsite.Theselayoutsareconsequentlyconcep-tualinnatureanddonotnecessarilyrepresentoptimumprojectarrangementsatthesites.Also,becauseofthelackofgeotechnicalinformationatseveralofthesites,judgementaldecisionshadtobemadeontheappropriatefoundationandabutmenttreatment.Theaccuracyofcostestimatesmadeinthesestudiesisprobablyintheorderofplusorminus30percent.(a)DesignAssumptionsInordertomaximizestandardizationofthelayouts,asetofbasicdesignassumptionsweredeveloped.Theseassumptionscoveredgeotechnical,hydro-logic,hydraulic,civil,mechanical,andelectricalconsiderationsandwereusedasgUidelinestodeterminethetypeandsizeofthevariouscomponentswithintheoverallprojectlayouts.TheyaredescribedindetailinAppen-dixD.Asstatedpreviously,otherthanatWatana,DevilCanyon,andDenali,littleinformationregardingsiteconditionswasavailable.Broadassumptionsweremadeonthebasisofthelimiteddata,andthoseassump-tionsandtheinterpretationofdatahavebeenconservative.Itwasassumedthattherelativecostdifferencesbetweenrockfillandcon-cretedamsatthesiteswouldeitherbemarginalorgreatlyinfavoroftherockfill.ThemoredetailedstudiescarriedoutsubsequentlyfortheWatanaandDevilCanyonsitesupportthisassumption(seeAppendixH).Therefore,arockfilldamhasbeenassumedatalldevelopmentsinordertoeliminatedifferentcostdiscrepanciesthatmightresultfromaconsidera-tionofdamfillratescomparedtoconcreteratesatalternativesites.(b)GeneralArrangementsAbriefdescriptionofthegeneralarrangementsdevelopedforthevarioussitesisgivenbelow.Plates1to7illustratethelayoutdetails.Table8.3summarizesthecrestlevelsanddamheightsconsidered.Inlayingoutthedevelopments,conservativearrangementshavebeenadopted,andwheneverpossibletherehasbeenageneralstandardizationofthecomponentstructures.(i)DevilCanyon(Plate1)-StandardArrangementThedevelopmentatDevilCanyonislocatedattheupperendofthecanyonatitsnarrowestpoint.Itconsistsofarockfilldam,sin-glespillway,powerfacilitiesincorporatinganundergroundpower-house,andatunneldiversion.Therockfilldamrisesabovethevalleyontheleftabutmentandterminatesinanadjoiningsaddledamofsimilarconstruction.Thedamrises675feetabovethelowestfoundationlevelwithacrest8-6 elevationof1470feetandavolumeof20millioncubicyards.Itconsistsofaninclinedimperviouscore,filterzones,andanover-lyingrockfillshell.Partoftheshellwillcornefromexcavationatthesitebutthemajoritywillbeblastrockfromlocalquarries.Itisanticipatedthatcoreandfiltermaterialswillalsobeavail-ablelocally.Thecoreisfoundedonsoundbedrock,andfullfoundationtreatmentisallowedforintheformofcontactgrouting,curtaingrouting,anddrainageviaanetworkofshaftsandgal-leries.Allalluviumandoverburdenmaterialareremovedfromtheshellfoundationarea.Diversioniseffectedbytwoconcrete-linedtunnelsdrivenwithintherockontherightabutment.Upstreamanddownstreamrockfillcofferdamswithaqueoustrenchcutoffsarefoundedontheriveralluviumandareseparatedfromthemaindam.Finalclosureisachievedbyloweringverticalliftslidinggateshousedinanup-streamstructurefollowedbyconstructionofasolidconcreteplugwithinthetunnelinlinewiththemaindamgroutcurtain.Subse-quentcontrolleddownstreamreleasesoccurvia asmalltunnelbypasslocatedatthegatestructureandaHowellBungervalvehousedwith-intheconcreteplug.Thespillwayislocatedontherightbankandconsistsofagatedoverflowstructureandaconcrete-linedchutelinkingtheoverflowstructurewithanintermediateandterminalstillingbasins.Suf-ficientspillwaycapacityisprovidedtopasstheProbableMaximumFloodsafely.Thepowerfacilitiesarelocatedontherightabutment.Themassiveintakestructureisfoundedwithintherockattheendofadeepap-proachchannelandconsistsoffourintegratedunits,eachservingindividualtunnelpenstocks.Eachunithasthreeoutletsatdifferentlevelsallowingforvariouslevelsofdrawoffandcorrespondingtemperaturecontrolofreleasesfromtheseasonallyfluctuatingreservoir.Eachoutletiscontrolledbyapairofverticalliftwheeledgatesandincorporatesprovisionforupstreamguardgates.Thepenstocksareconcrete-linedovertheirfulllengthexceptforthesectionjustupstreamofthepowerhousewhichissteel-linedtopreventseepageintothepowerhousearea.Therockinthisvicinityisgenerallybadlyfracturedbyblastingoperationsduringpower-housecavernconstructionactivity.Thepowerhousehousesfour100MW(or150MW)verticallymountedFrancistypeturbinesdrivingoverhead110/165MVaumbrellatypegenerators.Theseareservicedbytwooverheadcranesrunningthelengthofthemainpowerhallandanadjacentservicebay.Themainpowertransformersarehousedinanundergroundgallerylocatedabovethedrafttubes.Thisgalleryalsohousesagentrycraneforoperatingthedrafttubegatesrequiredtoisolatetheindividualdrafttubesfromthecommondownstreammanifoldandtailracetunnelsduringmaintenance.Thecontrolroomandofficesaresituatedatthesurfaceadjacenttoasurfaceswitchyard.8-7 -StagedPowerhouseAsanalternativetothefullpowerdevelopment,astagedpowerhousealternativewasalsoinvestigated.Thedamwouldbecompletedtoitsfullheightbutwithaninitialplantinstalledcapacityinthe200to300MWrange.Thecompletepowerhousewouldbeconstructedtogetherwithconcretefoundationsforthefutureunits,penstocksandtailracetunnelfortheinitial2-100MW(or150MW)units.Thecompleteintakewouldbeconstructedexceptforgatesandtrashracksrequiredforthesecondstage.Thesecondstagewouldincludeinstallationoftheremaininggatesandracksandconstructionofthecorrespondingpenstocksandtailracetunnelfortwonew100MW(or150MW)units.Civil,electrical,andmechanicalinstallationfortheseunitswouldalsobecompletedwithinthepowerhousearea,togetherwiththeenlargementofthesurfaceswitchyard,duringthesecondstage.(ii)Watana(Plates2and3)-StandardArrangement(seePlate3)Forinitialcomparativestudypurposes,thedamatWatanaisassumedtobearockfillstructurelocatedonasimilaralignmenttothatproposedinthepreviousCOEstudies.ItissimilarinconstructiontothedamatDevilCanyonwithanimperviouscorefoundedonsoundbedrockandanoutershellcomposedofblastedrockexcavatedfromasinglequarrylocatedontheleftabutment.Thedamrises880feetfromthelowestpointonthefoundationandhasanoverallvolumeofapproximately63millioncubicyards.Thecrestelevationis2225feet.Thediversionconsistsoftwinconcrete-linedtunnelslocatedwithintherockoftherightabutment.Rockfillcofferdams,alsowithim-perviouscoresandappropriatecutoffs,arefoundedonthealluviumandareseparatedfromthemaindam.Diversionclosureandfacili-tiesfordownstreamreleasesareprovidedforinamannersimilartothatatDevilCanyon.ThespillwayislocatedontheribankandissimilarinconcepttothatatDevilCanyonwithanintermediateandterminalstillingbasin.ThepowerfacilitiesarelocatedwithintheleftabutmentwithSlm1-larintake,undergroundpowerhouseandwaterpassageconceptstothoseatDevilCanyon.powerflitiesconsistoffour200MWturbine/generatorunitsgivingatotaloutputof800MW.-StagingConceptsAsanalternativetoinitialfulldevelopmentatWatana,stagingal-ternativeswereinvestigated.Theseincludestagingofbothdamandpowerhouseconstruction.StagingofpowerhousewouldbesimilartothatatDevilCanyon,thaStaI ilationof400MWandafurther400MWinStageII.8-8 Inordertostudythealternativedamstagingconceptithasbeenassumedthatthedamwouldbeconstructedforamaximumoperatingwatersurfaceelevationsome200feetlowerthanthatinthefinalstage.(SeePlate3).Thefirststagepowerhousewouldbecompletelyexcavatedtoitsfin-alsize.Threeoversized135MWunitswouldbeinstalledtogetherwithbaseconcreteforanadditionalunit.Alowlevelcontrolstructureandtwinconcrete-linedtunnelsleadingintoadownstreamstillingbasinwouldformthefirststagespillway.Forthesecondstage,thedamwouldbecompletedtoitsfullheight,theimperviouscorewouldbeappropriatelyraisedandadditionalrockfillwouldbeplacedonthedownstreamface.Itisassumedthatbeforeconstructioncommencesthetop40feetofthefirststagedamisremovedtoensurethecompleteintegrityoftheimperviouscorefortheraiseddam.AsecondspillwaycontrolstructurewouldbeconstructedatahigherlevelandincorporateadownstreamchuteleadingtotheStageIspillwaystructure.Theoriginalspillwaytunnelswouldbeclosedwithconcreteplugs.Anewintakestructurewouldbeconstructedutilizingexistinggatesandhoists,andnewpenstockswouldbedriventoconnectwiththeexistingones.Theexistingintakewouldbesealedoff.Oneadditional200MWunitwouldbeinstalledandtherequiredadditionalpenstockandtailracetunnelconstructed.Theexisting135MWunitswouldbeupgradedto200MW.Thiscanbeaccomplishedasdescribedbelow.-StagingGeneratingEquipmentTurbine-generatorequipmentoperatesatoneparticularspeedandus-uallyperformsatmaximumefficiencyforarelativelysmallrangeofheadvariation.Iftheheadvariessignificantly,theturbineeffi-ciencyisreduced,andunitoperationmayberougherwithincreasedpotentialforcavitation.Theoptionsavailableforselectionofturbine-generatorequipmentforstageddamconstructionareconsequentlyfairlyrestricted.Ingeneral,theseoptionswouldinclude:oSelectionoftheturbineandgeneratorsothattheequipmentwilloperatesatisfactorilyatoneintermediateheadwithsomelossofefficiencyduringboththeinitialandfinalstages;oModificationoftheturbine-generatorrotationalspeedforthefinalstageofoperation;oReplacementoftheturbinerunnerforthefinalstageofoperation;oReplacementoftherunnerandmodificationofturbine-generatorspeedforthefinalstageofoperation.Thefirstoptionisthesimplestalternativefromanequipmentpointofview.However,thechangeinheadwillresultinanefficiency8-9 penaltyinoneorperhapsbothstagesofoperation.Unlesstheheadchangeisrelativelysmall,theenergylossduetoreductioninefficiencywouldoutweightheadditionalcapitalexpenditureassoci-atedwiththeotheralternativesforstaging.Thesecondoptioninvolvesincreasingthegeneratorspeedwhenthereservoirlevelisraisedsoastomaintainturbineoperationatornearthebestefficiencypointduringbothstagesofoperation.Forfirststageoperation,theunitspeedmaybeselectedslightlylowerthannormaltoavoidexcessivespeedforthehigherheadoperation.Thegeneratorspeedchangecanbeaccomplishedbychangingthestatorwindingconnectionsandalsochangingtherimandrotorwindingelectricalconnectionstoreducethenumberofpoles.Achangeingeneratorspeedwouldresultinamarginalreductioningeneratorefficiency.Thethirdapproachinvolvesinstallinganewrunnerwithahigheroptimumoperatingheadoncethedamiscompletedtoitsfullheight.Suchanoptionhasbeenusedonotherprojects.Forverylargechangesinheadhowever,theshapeanddimensionsoftheinitialandfinalrunnersvaryconsiderably.Thismayresultindifficultiesindesigningtheturbinedistributortoaccommodatebothrunnerswithoutasacrificeinturbineefficiency.Thefourthmethodisessentiallyacombinationofthesecondandthirdoptions,resultinginachangebothintheturbinerunnerandtheunitspeedafterthedamisraisedtoitsfullheight.Suchanapproachwouldbesuitableforastagingschemeinvolvingasignifi-cantincreaseinhead.Inadditiontotheaboveconsiderationsitshouldbenotedthatthegenerators,transformers,circuitbreakers,busbars,powertrans-missioncableandancillaryequipmentmustbeselectedtoaccommo-datethehighercapacitywhichwillbeavailableinthefinalstageofoperation.ForthestageddamconstructionatWatana,maximumoperatingheadwouldincreasefromabout520feetto720feet.Theunitswouldberequiredtooperateforpartofthetimeundersubstantialdrawdownconditionsunderbothstages.Optiononewouldnotinthiscasebeappropriatebecauseofthelargerangeinheadinvolved.OptionfourontheotherhandisnotwarrantedbecauseitisdesignedtocopewithmuchlargerheadchangesthanarecurrentlyenvisagedatWatana.Preliminaryanalysesindicatethatofthetwooptionsre-maining,thethirdwouldprovidethemorecosteffectivesolutionforWatana.However,shouldstageddevelopmentappeareconomic,moredetailedstudieswouldberequiredfortheselectionofgener-atingequipment.Thisrefinementisnotexpectedtosignificantlyaffecttheoveralleconomicsofthestagingconcept,andthereforeisnotconsiderednecessaryforthisphaseofthestudy.(iii)HighDevilCanyon(Plate4)ThedevelopmentislocatedbetweenDevilCanyonandWatana.Thedarnisan855feethighrockfilldamsimilarindesigntoDevilCanyon,8-10 containinganestimated48millioncubicyardsofrockfillwithacrestelevationof1775feet.TheleftbankspillwayandtherightbankpowerhousefacilitiesarealsosimilarinconcepttoDevilCanyon.Theinstalledcapacityis800MW.Theleftbankdiversionsystemisformedbyupstreamanddownstreamearthjrockfillcofferdamsandtwinconcrete-linedtunnelswithtypicalcutoffanddownstreamreleasefacilities.Stagingisenvisagedastwostagesof400MWeachinthesamemannerasatDevilCanyonwiththedaminitiallyconstructedtoitsfullheight.(iv)SusitnaIII(Plate5)Thedevelopmentiscomprisedofarockfilldamwithanimperviouscoreapproximately670feethigh.Thedamwouldhaveavolumeofapproximately55millioncubicyardsandacrestelevationof2360feet.Thespillwayconsistsofaconcrete-linedchuteandasinglestillingbasinandislocatedontherightbank.Apowerhouseof350MWcapacityislocatedundergroundandthetwodiversiontunnelsarelocatedontheleftbank.(v)Vee(Plate6)A610feethighrockfilldamfoundedonbedrockwithacrestelevationof2350feetandtotalvolumeof10millioncubicyards,hasbeencon-sidered.SinceVeeislocatedfurtherupstreamthantheothermajorsitesthefloodflowsarecorrespondinglylower,thusallowingforareductioninsizeofthespillwayfacilities.Aspillwayutilizingagatedoverflowstructure,chute,andflipbuckethasbeenadoptedandislocatedwithintheridgeformingtherightabutmentofthedam.Thepowerfacilitiesconsistofa400MWundergroundpowerhouselocatedintheleftbankwithatailraceoutletwelldownstreamofthemaindam.Theintakeisfoundedinarockshouldertotheleftofthedam.Asecondaryrockfilldamisalsorequiredinthisvicinitytosealoffalowpoint.Twodiversiontunnelsareprovidedontherightbank.(vi)Maclaren(Plate7)Thedevelopmentconsistsofa185feethighearthfilldamfoundedonperviousriverbedmaterials.Crestelevationis2405feet.Thisreservoirwouldessentiallybeusedforregulatingpurposes.Althoughgeneratingcapacitycouldbeprovidedapowerhousehasnotbeenshownintheproposedlayout.Diversionisthroughthreeconduitslocatedinanopencutontheleftbankandfloodsaredischargedviaasidechutespillwayandstillingbasinontherightbank.8-11 (vii)Denali(Plate7)DenaliissimilarinconcepttoMaclaren.Thedamis230feethigh,ofearthfi11construction,andhasacrestelevationof2555feet.AsforMaclaren,nogeneratingcapacityisshown.Acombineddiversionandspillwayfacilityisprovidedbytwinconcreteconduitsfoundedinopencutexcavationintherightbankanddischargingintoacommonstillingbasin.(c)CapitalCostForpurposesofinitialcomparisonsofalternatives,constructionquantitiesweredeterminedforitemscomprisingthemajorworksandstructuresatthesites.Wheredetailordatawerenotsufficientforcertainwork,quantityestimateshavebeenmadebasedonpreviousAcres·experienceandthegeneralknowledgeofsiteconditionsreportedintheliterature.Inordertodeterminetotalcapitalcostsforvariousstructures,unitcostshavebeendevelopedfortheitemsmeasured.Thesehavebeenestimatedonthebasisofreviewsofratesusedinpreviousstudies,andofratesusedonsimilarworksinAlaskaandelsewhere.Whereapplicable,adjustmentfactorsbasedongeography,climate,manpowerandaccessibilitywereused.Technicalpublicationshavealsobeenreviewedforbasicratesandescalationfactors.Anoverallmobilizationcostof5percenthasbeenassumedandcampandcateringcostshavebeenbasedonapreliminaryreviewofconstructionman-powerandschedules.Anannualconstructionperiodof6monthshasbeenassumedforplacementoffillmaterialsand8monthsforallotheroperations.Nightworkhasbeenassumedthroughout.A20percentallowancefornon-predictablecontingencieshasbeenaddedasalumpsumtogetherwithatypicalallowanceforlargeprojectsof12percentforengineeringandadministrationcosts.ThetotalcapitalcostsdevelopedareshowninTables8.1,8.2,and8.4•ItshouldbenotedthatthecapitalcostsforMaclarenandUena1ishowninTable8.1and8.2havebeenadjustedtoincorporatethecostsof55MWand60MWplantsrespectively.8.6-FormulationofSusitnaBasinDevelopmentPlansTheresultsofthesitescreeningexercisedescribedinSection8.3indicatethattheSusitnaBasindevelopmentplanshouldincorporateacombinationofseveralmajordamsandpowerhouseslocatedatoneormoreofthefollowingsites:-DevilCanyon.-HighDevilCanyon.-Watana.-SusitnaIII.-Vee.8-12 naddition,thefollowingtwositesshouldbeconsideredascandidatesforplementaryupstreamflowregulation:-Maclaren-DenaliToestablishveryquicklythelikelyoptimumcombinationofdams,acomputerscreeningmodelwasusedtodirectlyidentifythetypesofplansthataremosteconomic.ResultsoftheserunsindicatethattheDevilCanyon/WatanaortheHighDevilCanyon/Veecombinationsarethemosteconomic.Inadditiontothesetwobasicdevelopmentplans,atunnelschemewhichprovidespotentialenviron-mentaladvantagesbyreplacingtheDevilCanyondambyalongpowertunnelandadevelopmentplaninvolvingthetwomosteconomicdamsites,HighDevilCanyonandWatana,werealsointroduced.ThesestudiesareoutlinedinmoredetailbelovJ.ThecriteriausedatthisstageoftheprocessforselectionofpreferredSusitnaBasindevelopmentplansaremainlyeconomic(seeFigure8.1).Asdiscussedbelow,environmentalconsiderationsareincorporatedintothefurtherassessloentoftheplansfinallyselected.ApplicationofScreeningModelBasically,thiscomputermodelcomparesbasindevelopmentplansforagiventotalbasinpowerandenergydemandandselectsthesites,approximatedamheights,andinstalledcapacitiesonaleastcostbasis.ThemodelincorporatesastandardMixedIntegerProgramming(MIP)algorithmfordeterminingtheoptimumorleastcostsolution.Inputsessentiallycomprisebasichydrologicdata,damvolume-costcurvesforeachsite,anindicationofwhichsitesaremutuallyexclusive,andatotalpowerdemandrequiredfromthebasin.Atimeperiodbytimeperiodenergysimulationprocessforindividualsitesandgroupsofsitesisincorporatedintothemodel.Themodelthensystematicallysearchesouttheleastcostsystemofreservoirsandselectsinstalledcapacitiestomeetthespecifiedpowerandenergydemand.AdetaileddescriptionofthemodelaswellastheinputandoutputdataaregiveninAppendixE.Asummaryofthisinformationispresentedbelow:(i)InputDataInputdatatothemodeltakethefollowingform:-Streamflow:Inordertoreducethecomplexityofthemodel,ayearisdividedintotwoperiods,summerandwinter,andflowsarespeci-fiedforeach.ForthesmallerdamsitessuchasDenali,Maclaren,Vee,andDevilCanyon,whichhavelittleornooveryearstoragecapability,onlytwotypicalyearsofhydrologyareinput.Thesecorrespondtoadryyear(90percentprobabilityofexceedence)andanaverageyear(50percentprobabilityofexceedence).Fortheotherlargersites,thefullthirtyyearsofhistoricalsummerandwinterflowsarespecified.8-13 8-14(ii)ModelRunsandResultsThemostimportantconclusionsthatcanbedrawnfromtheresults.showninTable8.5areasfollows:400MW-1750Gwh.800MW-3500Gwh.1200MW-5250Gwh.1400MW-6150Gwh.-Forenergyrequirementsofupto1750Gwh,theHighDevilCanyon,DevilCanyonortheWatanasitesindividuallyprovidethemosteco-nomicenergy.ThedifferencebetweenthecostsshownonTable8.5isaround10percent,whichissimilartotheaccuracythatcanbeexpectedfromthescreeningmodel.-Forenergyrequirementsofbetween1750and3500Gwh,theHighDevilCanyonsiteisthemosteconomic.DevelopmentsatWatanaandDevilCanyonare20to25percentmorecostly.-Run1:-Run2:-Run3:-Run4:-SiteCharacteristics:Foreachsite,storagecapacityversuscostcurvesareprovided.ThesecurvesweredevelopedfromtheengineeringlayoutspresentedinSection8.4.Utilizingtheselayoutsasabasis,thequantitiesforlowerleveldarnheightsweredeterminedandusedtoestimatethecostsassociatedwiththeselowerlevels.Figures8.4to8.6depictthecurvesusedinthemodelruns.ThesecurvesincorporatethecostoftheappropriategeneratingequipmentexceptfortheDenaliandMaclarenreservoirs,whicharetreatedsolelyasstoragefacilities.-BasinCharacteristics:ThemodelissuppliedwithinformationonthemutuallyexclusivesitesasoutlinedinFigures8.4to8.6.-PowerandEnergyDemand:Themodelissuppliedwithapowerandenergydemand.Thisisachievedbyspecifyingatotalgeneratingcapacityrequiredfromtheriverbasinandanassociatedannualplantfactorwhichisthenusedtocalculatetheannualenergydemand.AreviewoftheenergyforecastsdiscussedinSection5revealsthatbetweentheearliesttimeaSusitnaprojectcouldcorneonline(inearly1993)andtheendoftheplanningperiod(2010),approximately2200,4250,and9570Gwhofadditionalenergywouldberequiredforthelow,medium,andhighenergyforecasts,respectively.Intermsofcapacity,thesevaluesrepresent400,780,and1750MW.Basedonthesefigures,itwasdecidedtorunthescreeningmodelforthefollowingtotalcapacityandenergyvalues:TheresultsoftheserunsareshowninTable8.5.Becauseofthesimplifyingassumptionsthataremadeinthescreeningmodel,thethreebestsolutionsfromaneconomicpointofviewarepresented. -Forenergyrequirementsofbetween3500and5250GwhthecombinationsofeitherWatanaandDevilCanyonorHighDevilCanyonandVeearethemosteconomic.TheHighDevi1/SusitnaIIIcombinationisalsocompetitive.ItscostexceedstheWatana/Devi1Canyonoptionby11percentwhichiswithintheaccuracyofthemode1.-ThetotalenergyproductioncapabilityoftheWatana/Devi1CanyondevelopmentsisconsiderablylargerthanthatoftheHighDevilCanyon/Veealternativeandistheonlyplancapableofmeetingenergydemandsinthe6000Gwhrange.Thereasonswhythisscreeningprocessrejectedtheothersitesisasfollows:Exceptfortheonecase,SusitnaIIIisrejectedduetoitshighcapi-talcost.Thecostofenergyproductionatthissiteishighincom-parisonwithVee,evenallowingforthe150feetofthesystemheadthatislostbetweentheheadwatersofHighDevilCanyonandthetailwaterofVee.MaclarenandDenalihaveaverysmallimpactonthesystem'senergyproductioncapabilityandarerelativelycostly.TunnelSchemeAschemeinvolvingalongpowertunnelcouldconceivablybeusedtoreplacetheDevilCanyondamintheWatana/DevilCanyonSusitnadevelopmentplan.ItcoulddevelopsimilarheadforpowergenerationatcostscomparabletotheDevilCanyondamdevelopment,andmayprovidesomeenvironmentaladvan-tagesbyavoidinginundationofDevilCanyon.Obviously,becauseofthelowwinterflowsintheriver,atunnelalternativecouldbeconsideredonlyasasecondstagetotheWatanadevelopment.Conceptually,thetunnelalternativeswouldcomprisethefollowingmajorcomponentsinsomecombination,inadditiontotheWatanadamreservoirandassociatedpowerhouse:-Powertunnelintakeworks.-Oneortwopowertunnelsofuptofortyfeetindiameteranduptothirtymilesinlength.- Asurfaceorundergroundpowerhousewithacapacityofupto1200MW.- Are-regulationdamiftheintakeworksarelocateddownstreamfromWatana.Arrangementsforcompensationforlossofflowinthebypassedriverreach.8-15 Fourbasicalternativeschemesweredevelopedandstudied.AllschemesassumeaninitialWatanadevelopmentwithfullreservoirsupplylevelatelevation2200feetandtheassociatedpowerhousewithaninstalledcapac-ityof800MW.Figure8.7isaschematicillustrationoftheseschemes.-Scheme1:Thisschemecomprisesasmallre-regulationdamabout75feethigh,downstreamofWatana,withpowertunnelsleadingtoasecondpower-houseattheendofthetunnelnearDevilCanyon.ThispowerstationwouldoperateinserieswiththeoneatWatanasincethestoragebehindthere-regulationdamissmall.Essentially,there-regulationdampro-videsforconstantheadonthetunnelanddealswithsurgesinoperationatWatana.Thetwopowerhouseswouldoperateaspeakingstationsresult-inginflowandlevelfluctuationsdownstreamfromDevilCanyon.-Scheme2:ThisproposalalsoprovidesforpeakingoperationofthetwopowerhousesexceptthatthetunnelintakeworksarelocatedintheWatanareservoir.Initially,thepowerhouseatWatanawouldhave800MWin-stalledcapacitywhichwouldthenbereducedtosome70MWafterthetun-nelsarecompleted.ThiscapacitywouldtakeadvantageoftherequiredminimumflowfromtheWatanareservoir.ThepowerflowwouldbedivertedthroughthetunnelstothepowerhouseatDevilCanyonwithaninstalledcapacityofabout1150MW.DailyfluctuationsofwaterleveldownstreamwouldbesimilartothoseinScheme1forpeakingoperations.-Schemes3and4:TheseschemesprovideforbaseloadoperationatDevilCanyonpowerhouseandpeakingatWatana.InScheme3,thetunneldevel-opsonlytheDevilCanyondamheadandincludesa245feethighre-regulationdamandreservoirwiththecapacitytoregulatediurnalfluc-tuationsduetopeakingoperationatWatana.Thesiteforthere-regulationdamwaschosenbymeansofamapstudytoprovidesufficientre-regulationstorage,andislocatedatwhatappearstobeasuitabledamsite.InScheme4,thetunnelintakesarelocatedintheWatanares-ervoir.TheWatanapowerhouseinstalledcapacityforthisschemeis800MW,asfortheWatana-DevilCanyondevelopment,andisusedtosupplypeakingdemand.Table8.6listsallthepertinenttechnicalinformationandTable8.7,theenergyyieldsandcostsassociatedwiththesefourschemes.Ingeneral,developmentcostsarebasedonthesameunitcostsasthoseusedinotherSusitnadevelopments.Littlegeotechnicalinformationisavailableformuchoftheproposedtunnelroutes.Nevertheless,onthebasisofprecedent,tunnelconstructioncostsareestimatedontheassump-tionthatexcavationwillbedonebyconventionaldrillandblastopera-tionsandthattheentirelengthm~nothavetobelined.Tentativeas-sumptionsastotheextentofliningandsupportareasfollows:-31percentunlined.-34percentshotcrete-lined.-26percentconcrete-lined.9percentlinedwithsteelsetsandconcrete.8-16 Basedontheforegoingeconomicinformation,Scheme3producesthelowestcostenergy.AreviewoftheenvironmentalimpactsassociatedwiththefourtunnelschemesindicatesthatScheme3wouldhavetheleastimpact,primarilybe-causeitoffersthebestopportunitiesforregulatingdailyflowsdown-streamfromtheproject.Basedonthisassessment,andbecauseofitseconomicadvantage,Scheme3wasselectedasthemostappropriate.Moredetailedgeneralarrangementdrawingsforthisalternativev/ereproduced(Plates8and9)andcosted.ThecapitalcostestimateappearsinTable8.8.ItshouldbenotedthatthecostestimatesinthistabledifferslightlyfromthoseinTable8.5andreflecttheadditionallevelofde-tail.Theyalsoincorporatesingleanddoubletunneloptions.Forpur-posesofthesestudies,thedoubletunneloptionhasbeenselectedbecauseofitssuperiorreliability.Itshouldalsoberecognizedthatthecostestimatesassociatedwiththetunnelsareprobablysubjecttomorevaria-tionthanthoseassociatedwiththedamschemesduetogeotechnicaluncer-tainties.Inanattempttocompensatefortheseuncertainties,economicsensitivityanalysesusingbothhigherandlowertunnelcostshavebeenconducted.AdditionalBasinDevelopmentPlanAsnotedabove,theWatanaandHighDevilCanyondamsitesappeartobein-dividuallysuperiorineconomictermstoallothers.Anadditionalplanwasthereforedevelopedtoassessthepotentialfordevelopingthesetwositestogether.Forthisscheme,theWatanadamwouldbedevelopedtoitsfullpotentialeHO\'/ever,theHighDevilCanyondamwou1dbeconstructedtoacrestelevationof1470feettofullyutilizetheheaddownstreamfromWatana.CostsforthelowerlevelHighDevilCanyondamweredevelopedbyassumingthesamegeneralarrangementasforthehigherversionshowninPlate4andappropriatelyadjustingthequantitiesinvolved.SelectedBasinDevelopmentPlansTheessentialobjectiveofthisstepinthedevelopmentselectionprocessisdefinedastheidentificationof thoseplanswhichappeartowarrantfurther,moredetailedevaluation.TheresultsofthefinalscreeningprocessindicatethattheWatana/DevilCanyonandtheHighDevilCanyon/Veeplansareclearlysuperiortoallotherdamcombinations.Inaddition,itwasdecidedtostudyfurtherthetunnelschemeasanalternativetotheWatana/HighDevilCanyonplan.Associatedwitheachoftheseplansareseveraloptionsforstageddevelop-ment,includingstagedconstructionofthedamsand/orthepowergenerationfacilities.Forthismoredetailedanalysisofthesebasicplans,arangeofdifferentaproachestostagingthedevelopmentsareconsidered.Inordertokeepthetotaloptionstoareasonablenumberandalsotomaintainreasonablylargestagingstepsconsistentwiththetotaldevelopmentsize,stagingofonlythetwolargerdevelopments,i.e.WatanaandHighDevilCanyon,isconsidered.Thebasicstagingconceptsadoptedforthesedevelopmentsinvolvestagingbothdamandpowerhouseconstructionoralternativelyjuststagingpowerhouseconstruction.Powerhousestagesareconsideredin400MWincrements.8-17 8-18(i)Plan1ThesearesummarizedinTable8.9andareinvolvestheWatana-DevilCanyonsites,sites,Plan3theWatana-tunnelconceptCanyonsites.-Subplan2.1:ThisSubplaninvolvesconstructingtheHighDevilCanyondamfirstwithaninstalledcapacityof800MW.ThesecondstageinvolvesconstructingtheVeedamwithaninstalledcapacityof400MW.-Subplan3.1:ThisSubplaninvolvesinitialconstructionofWatanaandinstallationof800MWofcapacity.Thenextstageinvolvestheconstructionofthedownstreamre-regulationdamtoacresteleva-tionof1500feetanda15milelongtunnel.Atotalof300MWwouldbeinstalledattheendofthetunnelandafurther30MWatthere-regulationdam.Anadditional50MWofcapacitywouldbe'in-stalledattheWatanapowerhousetofacilitatepeakingoperations.-Subplan3.2:ThisSubplanisessentiallythesameasSubplan3.1exceptthatconstructionoftheinitial800MWpowerhouseatWatanaisstaged.-Subplan1.3:ThisSubplanissimilartoSubplan1.2exceptthatonlythepowerhouseandnotthedamatWatanaisstaged.-Subplan2.2:ForthisSubplan,theconstructionofHighDevilCanyondamisstagedfromacrestelevationof1630to1775feet.Theinstalledcapacityisalsostagedfrom400to800MW.AsforSubplan2.1,Veefollowswith400MWofinstalledcapacity.-Subplan2.3:ThisSubplanissimilartoSubplan2.2exceptthatonlythepowerhouseandnotthedamatHighDevilCanyonisstaged.-Subplan1.1:ThefirststageinvolvesconstructingWatanadamtoitsfullheightandinstalling800MW.Stage2involvesconstruct-ingDevilCanyondamandinstalling600MW.-Subplan1.2:ForthisSubplan,constructionoftheWatanadamisstagedfromacrestelevationof2060feetto2225feet.Thepower-houseisalsostagedfrom400MWto800MW.AsforSubplan1.1,thefinalstageinvolvesDevilCanyonwithaninstalledcapacityof600MW.Fourbasicplansareconsidered.brieflydescribedbelow.Plan1Plan2theHighDevilCanyon-VeeandPlan4theWatana-HighDevilUndereachplanseveralalternativesubplansareidentified,eachinvolvingadifferentstagingconcept.(ii)Plan2(iii)Plan3 (iv)Plan4Thissingleplanwasdevelopedtoevaluatethedevelopmentofthetwomosteconomicdamsites,WatanaandHighDevilCanyon,jointly.Stage1involvesconstructingWatanatoitsfullheightwithaninstalledcapacityof400MW.Stage2involvesincreasingthecapacityatWatanato800MW.Stage3involvesconstructingHighDevilCanyontoacrestelevationof1470'feetsothatthereservoirextendstojustdownstreamofWatana.InordertodevelopthefullheadbetweenWatanaandPortageCreek,anadditionalsmallerdamisaddeddown-streamofHighDevi1Canyon.ThisdamwouldbelocatedjustupstreamfromPortageCreeksoasnottointerferewiththeanadromousfisher-iesandwouldhaveacrestelevationof1030feetandaninstalledca-pacityof150MW.Forpurposesofthesestudies,thissiteisrefer-redtoasthePortageCreeksite.-EvaluationofBasinDevelopmentPlansoverallobjectiveofthisstepintheevaluationprocessistoselectthebasindevelopmentplan.Apreliminaryevaluationofplanswasini-allyundertakentodeterminebroadcomparisonsoftheavailablealternatives.iswasfollowedbyappropriateadjustmentstotheplansandamoredetailedluationandcomparison.PreliminaryEvaluationsTable8.9listspertinentdetailssuchascapitalcosts,constructionper-iodsandenergyyieldsassociatedwiththeselectedplans.Thecostinfor-mationwasobtainedfromtheengineeringlayoutstudiesdescribedinSec-tion8.4.Theenergyyieldinformationwasdevelopedusingamultireser-voircomputermodel.Thismodelsimulates,onamonthlybasis,theenergyproductionfromagivensystemofreservoirsforthe30-yearperiodforwhichstreamflowdataisavailable.Itincorporatesdailypeakingopera-tionsifthesearerequiredtogeneratethenecessarypeakcapacity.Allthemodelrunsincorporatepreliminaryenvironmentalconstraints.Seasonalreservoirdrawdownsarelimitedto150feetforthelargerand100feetforthesmallerreservoirs;dailydrawdownsfordailypeakingoperationsarelimitedto5feetandminimumdischargesfromeachreservoiraremaintainedatalltimestoensureallriverreachesremainwatered.Theseminimumdischargesweresetapproximatelyequaltotheseasonalaveragenaturallowflowsatthedamsites.Themodelisdrivenbyanenergydemandwhichfollo\'/sadistributioncor-respondingtotheseasonaldistributionofthetotalsystemloadasout-linedinSection5,Table5~10.Themodelwasusedtoevaluateforeachstageoftheplansdescribedabovetheaverageandfirmenergyandtheinstalledcapacityforaspecifiedplantfactor.Thisusuallyrequiredaseriesofiterativerunstoensurethatthenumberofreservoirfailuresinthe30-yearperiodwerelimitedtooneyear.Thefirmpowerwasassumedequaltothatdeliveredduringthesecondlowestannualenergyyieldinthesimulationperiod.Thiscorres-pondsapproximatelytothe95percentlevelofassurance.Amoredetaileddescriptionofthemodel,themodelruns,andtheaveragemonthlyenergyyieldsassociatedwiththedevelopmentplansisgiveninAppendixF.8-19 Arangeofsensitivityrunswasconductedtoexploretheeffectoftheres-ervoirdrawdownlimitationontheenergyyield.TheresultsoftheserunsaresummarizedinTable8.10.TheyindicatethatthedrawdownlimitationscurrentlyimposedreducethefirmenergyyieldforWatanadevelopmentbyapproximately6percent.(b)PlanModificationsIntheprocessofevaluatingtheschemes,itbecameapparentthattherewouldbeenvironmentalproblemsassociatedwithallowingdailypeakingop-erationsfromthemostdownstreamreservoirineachoftheplansdescribedabove.Inordertoavoidthesepotentialproblemswhilestillmaintainingoperationalflexibilitytopeakonadailybasis,re-regulationfacilitieswereincorporatedinthefourbasicplans.Thesefacilitiesincorporatebothstructuralmeasuressuchasre-regulationdamsandmodifiedoperation-alprocedures.Detailsofthesemodifiedplans,referredtoasE1toE4,arelistedinTable8.11.Abriefdescriptionofthechangesthatweremadefollows:(i)ElPlansForSubplans1.1to1.3alowtemporaryre-regulationdamiscon-structeddownstreamfromWatanaduringthestageinwhichthegenerat-ingcapacityisincreasedto800MW.Thisdamwouldre-regulatetheoutflowsfromWatanaandallowdailypeakingoperations.Ithasbeenassumedthatitwouldbepossibletoincorporatethisdamwiththedi-versionworksattheDevilCanyonsite,andanallowanceof$100millionhasbeenmadetocoveranyadditionalcostsassociatedwiththisapproach.Inthefinalstage,only400MWofcapacityisaddedtothedamatDevilCanyoninsteadoftheoriginal600MW.ReservoiroperatingrulesarechangedsothatDevilCanyondarnactsasthere-regulationdamforWatana.(ii)E2PlansForSubplans2.1to2.3apermanentre-regulationdamislocateddown-streamfromtheHighDevilCanyonsiteatthesametimethegeneratingcapacityisincreasedto800MW.Anallowanceof$140millionhasbeenmadetocoverthecostsofsuchadam.AnadditionalSubplanE2.4wasestablished.ThisplanissimilartoE2.3exceptthatthere-regulationdamisutilizedforpowerproduc-tion.ThedamsiteislocatedatthePortageCreeksitewithacrestlevelsetsoastoutilizethefullhead.A150MWpowerhouseisin-stalled.Asthisdamistoserveasare-regulatingfacility,itisconstructedatthesametimeasthecapacityofHighDevilCanyonisincreasedto800MW,i.e.duringStage2.(iii)E3PlanTheWatanatunneldevelopmentplanalreadyincorporatesanadequatedegreeofre-regulationandtheE3.1planis,therefore,identicaltotothe3.1plan.8-20 (iv)E4PlansAsfortheE1Plans,theE4.1planincorporatesare-regulationdamdownstreamfromWatanaduringStage2.AsfortheE1plans,ithasbeenassumedthatitwouldbepossibletoincorporatethisdamaspartofthediversionarrangementsattheHighDevilCanyonsite,andanallowanceof$100millionhasbeenmadetocoverthecosts.TheenergyandcostinformationpresentedinTable8.11isgraphicallydisplayedinFigure8.8whichshowsplotsofaverageannualenergyproductionversustotalcapitalcostsforalltheplans.Althoughthesecurvesdonotrepresentaccurateeconomicanalyses,theydogiveanindicationoftherelativeeconomicsoftheschemes.Theseevalua-tionsbasicallyreinforcetheresultsofthescreeningmodel;foratotalenergyproductioncapabilityofuptoapproximately4000Gwh,PlanE2(HighDevilCanyon)providesthemosteconomicenergywhileforcapabilitiesintherangeof6000Gwh,PlanE1(Watana-Devi1Canyon)isthemosteconomic.TheplanslistedinTable8.11aresubjectedtoamoredetailedanaly-sisinthefollowingsection.EvaluationCriteriaandMethodologyTheapproachtoevaluatingthevariousbasindevelopmentplansdescribedaboveistwofold:-Fordeterminingtheoptimumstagingconceptassociatedwitheachbasicplan(i.e.theoptimumsubp1an)economiccriteriaonlyareusedandtheleastcoststagingconceptisadopted.-Forassessingwhichplanisthemostappropriate,amoredetailedevalua-tionprocessincorporatingeconomic,environmental,social,andenergycontributionaspectsaretakenintoaccount.EconomicevaluationofanySusitnaBasindevelopmentplanrequiresthattheimpactoftheplanonthecostofenergytotherailbeltareaconsumerbeassessedonasystemwidebasis.Astheconsumerissuppliedbyalargenumberofdifferentgeneratingsources,itisnecessarytodeterminethetotalRailbeltsystemcostineachcasetocomparethevariousSusitnaBasindevelopmentoptions.Thebasictoolusedtodeterminethesystemcostsisacomputersimulation/planningmodel(calledOGP5)oftheentiregeneratingsystem.Inputtothismodelincludesthefollowing:Loadforecastoveraspecifiedperiodoftime(ascontainedinSection5,Table5.10).-Loaddurationcurves(asoutlinedinSection5.5).-Detailsoftheexistinggeneratingsystem(Section6.2).- Alistofallpotentialfuturethermalgeneratingsourceswithassociatedannualizedcosts,installedcapacities,fuelconsumptionrates,etc.(asoutlinedinSection6.5).8-21 -Fuelprices(asoutlinedinSection6.5).- Aspecifiedhydroelectricdevelopmentplan,i.e.theannualizedcosts,on-linedates,installedcapacities,andenergyproductioncapabilityofthevariousstagesoftheplan(asoutlinedinSections6.4and8.5).-Systemreliabilitycriteria.Forcurrentstudypurposes,alossofloadprobability,(LOLP)of.1day/yearisused.Utilizingtheaboveinformation,theprogramsimulatestheperformanceofthesystem,incorporatesthehydroelectricdevelopmentasspecified,andaddsthermalgeneratingresourcesasnecessarytomeettheloadgrov/thandtosatisfythereliabilitycriteria.Thethermalplantsareselectedsothatthepresentworthofthetotalgenerationcostisminimized.Asummaryoftheinputdatatothemodelandadiscussionoftheresultsfollows.AmoredetaileddescriptionofthemodelrunsispresentedinAppendixG.AsdiscussedinSection1.4,thebasiceconomicanalysesundertakeninthisstudyincorporateIIreallidiscountandescalationrates.TheparametersusedaresummarizedinTable8.12.TheeconomicliveslistedinthistablearethesameastheassumedeconomiclivesoutlinedinSection6.2.(d)InitialEconomicAnalysessTable8.13liststheresultsofthefirstseriesofeconomicanalysesun-dertakenforthebasicSusitnaBasindevelopmentplanslistedinTable8.11.TheinformationinTable8.13includesthespecifiedon-linedatesforthevariousstagesoftheplans,theOGP5runindexnumber,thetotalinstalledcapacityattheyear2010bycategory,andthetotalsystempre-sentworthcostin1980.Thepresentworthcostisevaluatedfortheperiod1980to2040,i.e.60years.TheOGP5modelisrunfortheperiod1980-2010;thereaftersteadystateconditions areassumedandthegenera-tionmixandannualcostsof2010areappliedtotheyears2011to2040.Thisextendedperiodoftimeisnecessarytoensurethatthehydroelectricoptionsbeingstudied,manyofwhichonlycomeon-linearound2000,areoperatedforperiodsapproachingtheireconomiclivesandthattheirfullimpactonthecostofthegenerationsystemaretakenintoaccount.ThehighlightsottheresultsinTable8.13canbesummarizedasfollows:(i)PlanE1-Watana-DevilCanyonStagingthedamatWatana(PlanEl.2)isnotaseconomicascon-structingittoitsfullheight(PlansE1.1andE1.3).Theeconomicadvantageofnotstagingthedamamountsto$180millionin1980.-Theresultsindicatethattothelevelofanalysisperformed,thereisnodiscerniblebenefitinstagingconstructionoftheWatanapowerhouse(PlansELIandEl.3).Itisconsideredlikely,however,thatsomedegreeofstagedpowerhouseconstructionwillultimatelybeincorporatedduetoeconomicconsiderationsandalsobecauseit8-22 providesmaximumflexibility.Forcurrentplanningpurposes,itisthereforeassumedthatthestagedpowerhouseconcept,i.ePlanE1.3,isthemostappropriateWatana-DevilCanyondevelopmentplan.AdditionalrunsperformedforvariationsofPlanE1.3indicatethatsystemcostswouldincreaseby$1,110mi11ioniftheDevilCanyondamstagewerenotconstructed.Furthermore,afiveyeardelayinconstructionoftheWatanadamwouldincreasesystemcostsby$220million.Theseincreasesareduetoadditionalhighercostthermalunitswhichmustbebroughtonlinetomeettheforecastdemandintheearly19901s.PlanE1.4indicatesthatshouldthepowerhousesizeatWatanaberestrictedto400MWtheoverallsystemcostwouldincreaseby$40million.(ii)PlanE2-HighDevilCanyon-Vee-PlansE2.1andE2.2werenotanalyzedasthesearesimilartoE1.1andE1.2andsimilarresultscanbeexpected.-TheresultsforPlanE2.3indicateitis$520millionmorecostlythanPlanE1.3.CostincreasesalsooccuriftheVeedamstageisnotconstructed.Acostreductionofapproximately$160millionispossibleiftheChakachamnahydroelectricprojectisconstructedinsteadoftheVeedam.-TheresultsofPlanE2.5indicatethattotalsystemgeneratingcostswouldgoupby$160millionifthetotalcapacityatHighDevilCanyonvlerelimitedto400MW.(iii)PlanE3TheresultsforPlanE3.1illustratethatthetunnelschemeversustheDevilCanyondamscheme(E1.3)addsapproximately$680milliontothetotalsystemcost.Theavailabilityofreliablegeotechnicaldatawouldundoubtedlyhaveimprovedtheaccuracyofthecostestimatesforthetunnelalternative.Forthisreason,asensitivityanalysiswasmadeasachecktodeterminetheeffectofhalvingthetunnelcosts.Thisanalysisindicatesthatthetunnelschemeisstillmorecostlyby$380million.(iv)PlanE4TheresultsindicatethatsystemcostsassociatedwithPlanE4.1ex-cludingthePortageCreeksitedevelopmentare$200millionmo~ethantheequivalentE1plan.IfthePortageCreekdevelopmentisincluded,agreaterincreaseincostwouldresult.EconomicSensitivityAnalysesPlansE1,E2,andE3weresubjectedtofurthersensitivityanalysestoassesstheeconomicimpactsofvariousloadgrowths.TheseresultsaresummarizedinTable8.14.8-23 TheresultsforlowloadforecastsillustratethatthemostviableSusitnaBasindevelopmentplansincludethe800MWplans,i.e.PlanE1.5andE2.5.Ofthesetwo,theWatana-DevilCanyonplanislesscostlythantheHighDevilCanyon-Veeplanby$210million.Highersystemcostsareinvolvedifonlythefirststagedamisconstructed,i.e.eitherWatanaorHighDevilCanyon.Inthiscase,theWatanaonlyplanis$90millionmorecostlythantheHighDevilCanyonplan.PlanE3variationsaremorecostlythanbothPlansE1andE2.Forthehighloadforecasts,theresultsindicatethatthePlanE1.3is$1040millionlesscostlythanE2.3.Thecostsofbothplanscanbereducedby$630and$680millionrespectivelybytheadditionoftheChakachamnadevelopmentasafourthstage.NofurtheranalyseswereconductedonPlanE4.Asenvisaged,thisplanissimilartoPlanE1withtheexceptionthatthelowermaindamsiteismovedfromDevilCanyonupstreamtoHighDevilCanyon.Theinitialanalysesout-linedinTable8.13indicatethisschemetobemoreexpensive.(f)EvaluationCriteriaAsoutlinedinthegenericmethodology(Section1.4andAppendixA),thefinalevaluationofthedevelopmentplansistobeundertakenbyaper-ceivedcomparisionprocessonthebasisofappropriatecriteria.Thefol-lowingcriteriaareusedtoevaluatetheshortlistedbasindevelopmentplans.Theygenerallycontaintherequirementsofthegenericprocesswiththeexceptionthatanadditionalcriterion,energycontribution,isadded.Theobjectiveofincludingthiscriterionistoensurethatfullconsidera-tionisgiventothetotalbasinenergypotentialthatisdevelopedbythevariousplans.(i)Economic:TheparameterusedisthetotalpresentworthcostofthetotalRail-beltgeneratingsystemfortheperiod1980to2040aslistedinTables8.14and8.15.(ii)Environmental:Aqualitativeassessmentoftheenvironmentalimpactontheecological,cultural,andaestheticresourcesisundertakenforeachplan.Emphasisisplacedonidentifyingmajorconcernssothatthesecouldbecombinedwiththeotherevaluationattributesinanoverallassessmentoftheplan.(iii)Social:Thisattributeincludesdeterminationofthepotentialnon-renewableresourcedisplacement,theimpactonthestateandlocalecono~,andtherisksandconsequencesofmajorstructuralfailuresduetpseis-micevents.Impactsontheeconomyrefertotheeffectsofaninvest-mentplanoneconomicvariables.8-24 (iv)EnergyContribution:Theparameterusedisthetotalamountofenergyproducedfromthespecificdevelopmentplan.Anassessmentoftheenergydevelopmentforegoneisalsoundertaken.Thisenergylossisinherenttotheplanandcannoteasilyberecoveredbysubsequentstageddevelop-ments.ResultsofEvaluationProcessThevariousattributesoutlinedabovehavebeendeterminedforeachplanandaresummarizedinTables8.16through8.24.Someoftheattributesarequantitativewhileothersarequalitative.Overallevaluationisbasedonacomparisonofsimilartypesofattributesforeachplan.Incaseswheretheattributesassociatedwithoneplanallindicateequalityorsuperior-itywithrespecttoanotherplan,thedecisionastothebestplanisclearcut.Inothercaseswheresomeattributesindicatesuperiorityandothersinferiority,thesedifferencesarehighlightedandtrade-offdecisionsaremadetodeterminethepreferreddevelo~nentplan.Incaseswherethesetrade-offshavehadtobemade,theyarerelativelyconvincingandthedecisionmakingprocesscan,therefore,beregardedasfairlyrobust.Inaddition,thesetrade-offsareclearlyidentifiedsotherecordercaninde-pendentlyanswerthejudgementdecisionsmade.Theoverallevaluationprocessisconductedinaseriesofsteps.Ateachstep,onlyapairofplansisevaluated.Thesuperiorplanisthenpassedontothenextstepforevaluationagainstanalternativeplan.(i)DevilCanyonDamVersusTunnelThefirststepintheprocessinvolvestheevaluationoftheWatana-DevilCanyondamplan(E1.3)andtheWatanatunnelplan(E3.1).AsWatanaiscommontobothplans,theevaluationisbasedonacompari-sonoftheDevilCanyondamandtunnelschemes.Inordertoassistintheevaluationintermsofeconomiccriteria,additionalinformationobtainedbyanalyzingtheresultsoftheOGP5computerrunsisshowninTable8.16.Thisinformationillustratesthebreakdownofthetotalsystempresentworthcostintermsofcapi-talinvestment,fuelandoperationandmaintenancecosts.EconomicComparisonFromaneconomicpointofview,theDevilCanyondamschemeissu-perior.AssummarizedinTables8.16and8.17,onapresentworthbasis,thetunnelschemeis$680millionorabout12percentmoreexpensivethanthedamscheme.Foralowdemandgrowthrate,thiscostdifferencewouldbereducedslightlyto$610million.Evenifthetunnelschemecostsarehalved,thetotalcostdifferencewouldstillamountto$380million.AshighlightedinTable8.17,con-siderationofthesensitivityofthebasiceconomicevaluationtopotentialchangesincapitalcostestimate,theperiodofeconomicanalysis,thediscountrate,fuelcosts,fuelcostescalation,andeconomicplantlivesdonotchangethebasiceconomicsuperiorityofthedamschemeoverthetunnelscheme.8-25 -EnvironmentalComparisonTheenvironmentalcomparisonofthetwoschemesissummarizedinTable8.18.Overall,thetunnelschemeisjudgedtobesuperiorbecause:oItoffersthepotentialforenhancinganadromousfishpopula-tionsdownstreamofthere-regulationdamduetothemoreuniformflowdistributionthatwillbeachievedinthisreach;oItinundates13mileslessofresidentfisherieshabitatinriverandmajortributaries;oIthasalowerimpactonwildlifehabitatduetothesmallerin-undationofhabitatbythere-regulationdam;oIthasalowerpotentialforinundatingarcheologicalsitesduetothesmallerreservoirinvolved;oItwouldpreservemuchofthecharacteristicsoftheDevilCan-yongorgewhichisconsideredtobeanaestheticandrecrea-tionalresource.SocialComparisonTable8.19summarizesthe evaluationintermsofthesocialcri-teriaofthetwoschemes.Intermsofimpactonstateandlocaleconomicsandrisksduetoseismicexposure,thetwoschemesareratedequally.However,thedamschemehas,duetoitshigherenergyyield,morepotentialfordisplacingnonrenewableenergyresources,andthereforescoresaslightoverallplusintermsofthesocialevaluationcriteria.EnergyComparisonTable8.20summarizesthe evaluationintermsoftheenergsycon-tributioncriteria.Theresultsshownthatthedamschemehasagreaterpotentialforenergyproductionanddevelopsalargerportionofthebasin'spotential.Thedamsch~neisthereforejudgedtobesuperiorfromtheenergycontributionstandpoint.-OverallComparisonTheoverallevaluationofthetwoschemesissummarizedinTable8.21.Theestimatedcostsavingof$680millioninfavorofthedamschemeisconsideredtooutweighthereductionintheoverall·environmentalimpactofthetunnelscheme.Thedamschemeisthereforejudgedtobesuperioroverall.(ii)Watana-DevilCanyonVersusHighDevilCanyon-VeeThesecondstepinthedevelopmentselectionprocessinvolvesaneval-uationoftheWatana-DevilCanyon(E1.3)andtheHighDevilCanyon-Vee(E2.3)developmentplans.8-26 -Economic.ComparisonIntermsoftheeconomiccriteria(seeTables8.16and8.17)theWatana-Devi1Canyonplanislesscostlyby$520million.Asforthedam-tunnelevaluationdiscussedabove,considerationofthesensitivityofthisdecisiontopotentialchangesinthevariousparametersconsidered(i.e.loadforecast,discountrates,etc.)doesnotchangethebasicsuperiorityoftheWatana-Devi1CanyonP1an.-EnvironmentalComparisonTheevaluationintermsoftheenvironmentalcriteriaissummarizedinTable8.22.Inassessingtheseplans,areachbyreachcompari-sonismadeforthesectionoftheSusitnaRiverbetweenPortageCreekandtheTyoneRiver.TheWatana-DevilCanyonschemewou1dcreatemorepotentialenvironmentalimpactsintheWatanaCreekarea.However,itisjudgedthatthepotentialenvironmentalim-pactswhichwouldoccurintheupperreachesoftheriverwithaHighDevilCanyon-Veedevelopmentaremoresevereincomparisonovera11.Fromafisheriesperspective,bothschemes\'lOu1dhaveasimilareffectonthedownstreamanadromousfisheriesalthoughtheHighDevilCanyon-VeeschemewouldproduceaslightlygreaterimpactontheresidentfisheriesintheUpperSusitnaBasin.TheHighDevilCanyon-Veeschemewouldinundateapproximately14percent(15miles)morecriticalwinterriverbottommoosehabitatthantheWatana-Devi1Canyonscheme.TheHighDevilCanyon-VeeschemewouldinundatealargeareaupstreamoftheVeesiteutil-izedbythreesubpopu1ationofmoosethatrangeinthenortheastsectionofthebasin.TheWatana-Devi1Canyonschemewouldavoidthepotentialimpactsonmooseintheuppersectionoftheriver;however,alargerpercentageoftheWatanaCreekbasinwouldbeinundated.Theconditionofthesubpopu1ationofrnooseutilizingthisWatanaCreekBasinandthequalityofthehabitatappearstobedecreas-ing.Habitatmanipulationmeasurescouldbeimplementedinthisareatoimprovethemoosehabitat.Nevertheless,itisconsideredthattheupstreammoosehabitatlossesassociatedwiththeHighDevilCanyon-VeeschemewouldprobablybegreaterthantheWatanaCreeklossesassociatedwiththeWatana-Uevi1Canyonscheme.Amajorfactortobeconsideredincomparingthetwodevelopmentplansisthepotentialeffectsoncaribouintheregion.Itisjudgedthattheincreasedlengthofriverflooded,especiallyup-streamfromtheVeedamsite,wouldresultintheHighDevilCanyon-VeeplancreatingagreaterpotentialdiversionoftheNe1chinaherd'srange.Inaddition,alargerareaofcaribourangewouldbedirectlyinundatedbytheVeereservoir.8-27 TheareafloodedbytheVeereservoirisalsoconsideredimportanttosomekeyfurbearers,particularlyredfox.InacomparisonofthisareawiththeWatanaCreekareathatwouldbeinundatedwiththeWatana-DevilCanyonscheme,theareaupstreamofVeeisjudgedtobemoreimportantforfurbearers.Aspreviouslymentioned,theareabetweenDevilCanyonandtheOshetnaRiverontheSusitnaRiverisconfinedtoarelativelysteeprivervalley.Alongthesevalleyslopesarehabitatsimportanttobirdsandblackbears.AstheWatanareservoirwouldfloodtheriversectionbetweentheWatanaDamsiteandtheOshetnaRivertoahigherelevationthanwouldtheHighDevilCanyonreservoir(2200feetascomparedto1750feet)theHighDevilCanyon-Veeplanwouldretaintheintegrityofmoreofthisrivervalleyslopehabitat.Fromthearcheologicalstudiesdonetodate,theretendstobeanincreaseinsiteintensityasoneprogressestOHardsthenortheastsectionoftheUpperSusitnaBasin.TheHighDevilCanyon-Veeplanwouldresultinmoreextensiveinundationandincreasedaccesstothenortheasterlysectionofthebasin.Thisplanisthereforejudgedtohaveagreaterpotentialfordirectlyorindirectlyaffectingarcheologicalsites.DuetothewildernessnatureoftheUpperSusitnaBasin,thecrea-tionofincreasedaccessassociatedwithprojectdevelopmentcouldhaveasignificantinfluenceonfutureusesandmanagementofthearea.TheHighDevilCanyon-Veeplanwouldinvolvetheconstruc-tionofadamattheVeesiteandthecreationofareservoirinthemorenortheasterlysectionofthebasin.ThisplanwouldthuscreateinherentaccesstomorewildernessthanwouldtheWatana-DevilCanyonscheme.Asitiseasiertoextendaccessthantolimitit,inherentaccessrequirementsareconsidereddetrimentalandtheWatana-DevilCanyonschemeisjudgedtobemoreacceptableinthisregard.Exceptfortheincreasedlossofrivervalley,bird,andblackbearhabitattheWatana-DevilCanyondeveloprnentplanisjudyedtobemoreenvironmentallyacceptablethantheHighDevilCanyon-Veeplan.AlthoughtheWatana-DevilCanyonplanisconsideredtobethemoreenvironmentallycompatibleUpperSusitnadevelopmentplan,theactualdegreeofacceptabilityisaquestionbeingaddressedaspartofongoingstudies.EnergyComparisonTheevaluationofthetwoplansintermsofenergycontributioncriteriaissummarizedinTable8.23.TheWatana-DevilCanyonschemeisassessedtobesuperiorduetoitshigherenergypoten-tialandthefactthatitdevelopsahigherproportionofthebasin1spotential.8-28 -SocialComparisonTable8.19summarizestheevaluationintermsofthesocialcriter-ia.Asinthecaseofthedamversustunnelcomparison,theWatana-DevilCanyonplanisjudgedtohaveaslightadvantageovertheHighDevilCanyon-Veeplan.Thisisbecauseofitsgreaterpo-tentialfordisplacingnonrenewableresources.-OverallComparisonTheoverallevaluationissummarizedinTable8.24andindicatesthattheWatana-DevilCanyonplansaregenerallysuperiorforalltheevaluationcriteria.(iii)PreferredSusitnaBasinDevelopmentPlanComparisonsoftheWatana-DevilCanyonplanwiththeWatana-tunnelplanandtheHighDevilCanyon-VeeplansarejUdgedtofavortheWatana-DevilCanyonplanineachcase.TheWatana-DevilCanyonplanisthereforeselectedasthepreferredSusitnaBasindevelopmentplan,asabasisforcontinuationofmoredetaileddesignoptimizationandenvironmentalstudies.ComparisonofGenerationScenariosWithandWithouttheSusitnaBasinDevelopmentPlansectionoutlinestheresultsofthepreliminarystudiesundertakentocom-parethepreferredRailbeltgenerationscenarioincorporatingtheselectedWatana-DevilCanyondarndevelopmentplan,withalternativegenerationscenarios.Thesestudiesarenotintendedtodevelopcomprehensiveanddetailedalternativegeneratingscenariosbutmerelytoobtainapreliminaryassessmentofthefeasi-bilityoftheSusitnaplanintermsofeconomic,environmental,andsocialcri-teria.Themainalternativegeneratingscenarioconsideredistheall-thermaloption,ndadetailedevaluationofthe"withSusitna"andtheall-thermalgenerationscenariosiscarriedout.Inadditiontothis,alessdetailedassessmentofthegeneratingscenariosincorporatingnon-SusitnaBasinhydrodevelopmentisalsoconducted.Theobjectiveofthelatterevaluationistoassesstheeconom-icsofdevelopingalternativeandgenerallysmallerhydroprojects.Amorecom-prehensivecomparisonwouldrequiremoredetailedanalysesoftheenvironmentalandtechnicalaspectsateachofthesiteswhicharenotbeingundertakenunderthecurrentstudies."WithoutSusitna"GenerationScenariosThedevelopmentandevaluationofRailbeltgenerationplansincorporatingall-thermalandthermalplusnon-Susitnahydroelectricalternatives,isdiscussedinSection6.Resultsofall-thermalandthermalwithSusitnaalternativesaregiveninTable6.4.8-29 (b)ComparisonofAll-Thermaland"WithSusitna"GenerationScenarios(i)EconomicComparisonIntermsofeconomiccriteria,the"withSusitna"scenariois$2280millionlesscostlythantheall-thermaloption.Inordertoexplorethesensitivityofthiscomparisoninmoredetail,severaladditionalrunswerecarriedoutwiththeOGP5model.Fortheseruns,parameterssuchasprojectedloadgrowth,interestrates,fuelcostsandescalationrates,economiclives,andcapitalcostswerevariedandtheimpactontheoverallsystemcostsassessed.ThedetailedresultsarepresentedinTable8.25andaresummarizedinTable8.26.Abriefoutlineoftheseresultsfollows.Theeconomicadvantageofthe"vJithSusitna"scenariodecreaseswithdecreasingloadgrowthbutstillamountsto$1280millionfortheverylowforecast.Alowerlimitthermalplantcapitalcostestimatewasalsoconsidered.ThecostestimatewasbasedontheminimumAlaskacostfactoradjustmentreportedintheliteratureratherthantheaveragefactorusedforthestandardcostestimateswhichappearinTable6.4.Eventhoughthisresultsina72percentreductioninthethermalcapitalcost,the"withSusitna"scenarioisstill$1850millionmoreeconomic.ThesecondtypeofcapitalcostsensitivityruninvolvedincreasingtheSusitnaBasinhydrodevelopmentcostby50percenttorepresentanextremeupperlimit.Evenwiththiscostad-justment,the"withSusitna"generatingscenariocostsarestilllessthantheall-thermalscenarioby$1320million.AsshowninTable8.26,shorteningtheperiodofeconomicanalysisfrom60to30years(i.e.to1980-2010)reducesthenetbenefitto$960million.Theinterestratesensitivityrunresultsindicatethatthe"withSusitna"scenarioismoreeconomicforrealinterestratesofzerotoeightpercent.Atratesabovethis,thethermalscenariobecomesmoreeconomic.Afuelcostsensitivityrunusinganassumed20percentreductiontotheestimatedcostoffuelreducesthecostdifferenceto$1810million.Fuelcostescalationisanimportantparameterandthesensitivityanalysesshowthatforzeropercentescalationonallfuelsthedif-ferenceintotalsystemcostsreducesto$200million.Azeropercentescalationrateforcoal-onlyreducesthisdifferenceto$1330mi11ion.Thefinalsensitivityrunsassumedtheeconomiclivesofall-thermalunitsisextendedby50percent.Thisreducesthecostdifferenceto$1800million.Theaboveresultsindicatethatthe"withSusitna"scenarioremainsthemoreeconomicplanforawiderangeofparameters.Atrealinter-estratesexceeding8percent,theall-thermaloptionbecomesmoreattractive.Itis,however,unlikelythatsuchhighrateswouldevermaterialize.Althoughtheneteconomicadvantageofthe"withSusitna"scenarioissignificantlyreduced,azerofuelcostescalationratestillresultsinamoreexpensiveall-thermalgenerationscenario.8-30 (ii)SocialComparisonTheevaluationintermsofsocialcriteriaissummarizedinTable8.27.The"withSusitna"scenarioprovidesgreaterpotentialfornon-renewableresourceconservationandis,therefore,regardedassuperiorfromthispointofview.Thereisinsufficientinformationavailableatthistimetofullyevaluatetheimpactonthestateandlocaleconomics.Thepatternofpowerinvestmentexpenditureswillprobablytendtobemoreregularwiththeall-thermalplanandhencethereispotentiallyamoregrad-ualimpactthanwiththeSusitna-inclusivegenerationplan.ThetimingoftheSusitnatypeinvestmentisprobablymoredisruptiveinrelationtootherlargescaleAlaskanprojects.However,thiscouldresultincountercyclicalinvestmentthatwouldtendtoreducesuchdisruptions.(iii)EnvironmentalComparisonTable8.28broadlysummarizestheenvironmentalimpactsassociatedwiththetwoscenarios.Asindicated,bothhydroandthermaldevel-opmenthavepotentialforenvironmentalimpact.However,theextenttowhichthepotentialimpactsarerealizedisverysitespecific.Asspecificinformationonpotentialfuturecoal-firedgeneratingsourcesisnotavailableatthistime,theoverallcomparisonisgenericratherthansitespecific.(iv)OverallComparisonAnoverallevaluationissummarizedinTable8.29.Thisindicatesthatthe"withSusitna"scenarioisclearlysuperiorwithregardtotheeconomiccriteriaandsuggeststhatthereisnotadistinguish-abledifferencebetweentheevaluationsbasedonenvironmentalandsocialcriteria.Itisthereforeconcludedthatthescenarioincor-poratingtheWatana-DevilCanyonplanissuperiortotheall-thermalscenario.Comparisonofthe"WithSusitna"andAlternativeHydroGeneratingScenariosComparisonofthe"with-Susitna"andalternativehydroRailbeltgenerationscenarioshavebeenmadeonlyonthebasisofeconomics.Althoughprelimi-naryscreeningofthealternativehydroelectricdevelopmentsismadeasdescribedinSection6,theabsenceofimmediatesite-specificdatapre-ventsamoredetailedassessmentofnon-economicaspects.The"with-Susitna"scenarioisgenerally$1190millionmoreeconomicthanthescenarioincorporatingthealternativehydrodevelopments.AlthoughdevelopmentoftheSusitnaBasinismoreeconomicthandevelopingalterna-tivehydro,thisdoesnotimplythatalternativehydroshouldbeneglected.Infact,asseveralofthecombinationrunsinvolvingbothSusitnaandnon-Susitnahydroalternativesindicate,itmaybeeconomicallyadvantageoustoconsiderdevelopmentofseveralalternativehydrositesinconjunctionwithSusitna.8-31 TABLE B.1 -POTENTIAL HYOROELECTRIC DEVELOPMENT Average Econornic 1 Dam Capital Installed Annual Cost of Source Proposed Height Upstream Cost CaR8city Energy Energy of Site Type Ft.Regulation $million (MW)Gwh $/1000 kWh Data Gold Creek 2 Fi II 19~Yes 9~~26~1,14~37 USBR 1953 Olson (Susitna I I)Concrete 16~Yes 6~~2~~915 31 USBR 1953 KAISER 1974 COE 1975 Devil Canyon Concrete 675 No B30 250 1,420 27 This Study Yes 1,000 600 2,9BO 17 " High Devil Canyon "(Susitna I)Fill B55 No 1,500 BO~3,540 21 " Devil Creek 2 Fi II Approx No B50 CO Watana Fill BB~No 1,B60 BOO 3,250 2B "I W N Susitna II I Fill 670 No 1,390 350 1,5BO 41 " Vee Fill 61~No 1,060 400 1,371l 37 " t4aclaren 2 Fill 1B5 No 5311 4 55 1BO 124 " Denali Fill 230 No 4B~4 60 245 B1 " Butte Creek 2 Fi 11 Approx No -41l 130 3 -USBR 1953 150 Tyone 2 Fill Approx No -6 22 3 -USBR 1953 61l ~: (1 )Includes AFOC,Insurance,Amortization,and Operation &:Maintenance Costs. (2)No detailed engineering or energy studies undertaken as part of this stUdy. (3)These are approximate estimates and serve only to represent the potential of these two dam sites in perspective. (4)Include estimated costs of power generation facility. TABLE B.2 -COST COMPARISONS 00 I W W o A M Site Gold Creek Olson (SlJsitna I I) Devil Canyon High Devil Canyon (SlJsitna I) Devil Creek Watana Susitna III Vee Maclaren Denali Notes: Capital Cost Estimate 2 (1980 $) A eRE 5 198U o 1 HER 5 Installed caplEs I Cost lnsEe [led CapJ.tai Cost Source and Type Capacity -MW $million Capacity -MW $million Date of Data Fi II --2601 B90 USRB 1968 Concrete -1901 550 COE 1975- Fill 600 1,000 Concrete Arch --776 630 COE 1975 Concrete Gravity --776 910 COE 1978 Fill 800 1,500 700,1,480 COE 1975 Fill Fill 800 1,860 792 1,630 COE 1978 Fill 350 1,390 445 -KAISER 1974 Fill 400 1,060 -770 COE 1975 Fi 11 55 530 Fill 60 480 None 500 COE 1975 (1)Dependable Capacity (2)Excluding Anchorag8/Fairbanks transmission intertie,but including local access and transmission. "--~""'~-~-~'-, TA6LE6.3-DAMCRESTANDFULLSUPPLVLEVELSstagedFullDamAverageDamDamSupplyCrestTailwaterHeight1SiteConstructionLevel-Ft.Level-Ft.Level-ft.ft.GoldCreekNo670860660290OlsonNo1,020 1,030810310PortageCreekNo1,020 1,030870250DevilCanyon-intermediateheightNo1,250 1,270690465DevilCanyon-fullheightNo1,4501,470690675HighDevilCanyonNo1,6101,6301,030710No1,750 1,7751,030855WatanaVes2,0002,0601,465680Stage22,20112,2251,465680SusitnaIIINo2,3402,3601,610670VeeNo2,3302,3501,925610MaclarenNo2,395 2,405 2,300165DenaliNo2,5402,5552,405230Notes:(1)Tofoundationlevel.8-34 TA8LE 8.4 -CAPITAL COST ESTIMATE SUMMARIES SUSITNA 8ASIN DAM SCHEMES COST IN $MILLION 1980 Devl1-e-anyon High DevI1 Canyon Watana 5usJ.tna III Vee Maclaren DenaTI 1470 ft Crest 1775 ft Crest 2225 ft Crest 2360 ft Crest 2350 ft Crest 2405 ft Crest 2250 ft Crest Item 600 MW 800 MW 800 MW •330 MW 400 MW No power No power 1)Lands,Damages &Reservoirs 26 11 46 13 22 25 38 2)Diversion Works 50 48 71 88 37 118 112 3)Main Dam 166 432 536 398 183 106 100 4)Auxi 1 iary Dam 0 0 0 0 40 0 0 5)Powe r System 195 232 244 140 175 0 0 6)Spillway System 130 141 165 121 74 0 0 7)Roads and Bridges 45 68 96 70 80 57 14 ro 8)Transmission Line 10 10 26 40 49 0 0 I W 9)Camp Facilities and Support 97 140 160 130 100 53 50U"1 10)Miscellaneous1 8 8 8 8 8 5 5 11)Mobilization and Preparation 30 47 57 45 35 15 14 Subtotal 757 1137 1409 1053 803 379 333 Contingency (20%)152 227 282 211 161 76 67 Engineering and Owner's Administration (12%)91 136 169 126 96 45 40 __TOTAL 1000 1500 1860 1390 1060 500 440 Notes: (1)Includes recreational facilities,buildings and grounds and permanent operating equipment. TABLE B.5 -RESULTS OF SCREENING MOOEL Total Demand First Second o a. Cap.Energy Site Site Cost Site Run MW GWh Names Names $million Names 1 400 1750 High 1580 400 B85 Devil 1450 400 970 Watana 1950 400 9BO Devil Canyon Canyon 2 800 3500 High 1750 800 1500 Watana 1900 450 1130 Watana 2200 BOO 1B60 Devil Canyon Devil Canyon 1250 350 710 TOTAL 800 1840 CO I 3 1200 5250 Watana 2110 700 1690 High 1750 BOO 1500 High 1750 820 1500w cr>Devil Devil Canyon Canyon Devil 1350 500 800 Vee 2350 400 1060 Susitna 2300 380 1260 Canyon III TOTAL 1200 2490 TOTAL 1200 2560 TOTAL 1200 2760 4 1400 6150 Watana 2150 740 1770 N 0 SOL UTI 0 N N 0 SOL UTI 0 N Devil 1450 660 1000 Canyon TA8LE8.6-INFORMATIONONTHEDEVILCANYONDAMANDTUNNELSCHEMESuevIlCanyonlunneISchemeItemDamZ34ReservoirArea(Acres)7,5~032003,9000RiverMilesFlooded31.62.0015.80TunnelLength(Miles)0272913.529TunnelV~lumea11,97612,8633,7325,131(1000Yd)CompensatingFlowReleasefrom5001Watana(cfs)a1,0001,0001,000Downstream2ReservoirVolume(1000Acre-feet)1,1009.5350DownstreamDa~62575245Height(feet)TypicaiDailyRangeofDischargeFromDevilCanyon6,~004,OO~4,0008,3003,900Powerhousetototototo(cfs)13,noo14,00014,0008,9004,200ApproximateMaximumDailyFluctuationsinDownstreamReservoir(feet)2154Notes:~1,000efscompensatingflowreleasefromthere-regulationdam.3DownstreamfromWatana.Estimated,aboveexistingrockelevation.8-37 TA8LE 8.7 -DEVIL CANYON TUNNEL SCHEMES COSTS,POWER OUTPUT AND AVERAGE ANNUAL ENERGY W-al:-ana -De-vil Tanyon Tunnel Installed Capacity (MW) Sta~ STAGE 1: Watana Dam STAGE 2: Tunnel: -Scheme 1 -Scheme 2 0:>-Scheme 32 Iw -Scheme 4 0:>- ~: 800 800 70 850 800 550 1,150 330 365 Increase1 in Installed Capacity (MW) 550 428 380 365 Devil Canyon Average Annu81 Energy (Gwh) 2,050 4,750 2,240 2,490 1 .Increase ~n Average Annual Energy (Gwh) 2,050 1,900 2,180 890 Tunnel Scheme Total Project Costs $Million 1980 2320 1220 1490 3Cost of Additionlll Energy (mills/kWh) 42.6 52.9 24.9 73.6 (1)Increase over single Watana,800 MW development 3250 Gwh/yr (2)Includes power and energy produced at re-regulation dam (3)Energy cost is based on an economic analysis (i.e.using 3 percent interest rate) TABLEB.B-CAPITALCOSTESTIMATESUMMARIESTUNNELSCHEMESCOSTSIN$MILLION1980ItemLandanddamages,reservoirclearingDiversionworksRe-regulatiandamPowersystem(a)Maintunnels(b)Intake,powerhouse,tailraceandswitchyardSecondarypowerstationSpillwaysystemRoadsandbridgesTransmissionlinesCampfacilitiesandsupportMiscellaneous*MobilizationandpreparationTOTALCONSTRUCTIONCOSTContingencies(20%)Engineering,andOwnerlsAdministrationTOTALPROJECTCOST8-39557123lWO.5lJFtdistunnels14351026BO214242151318471,1372271361,500One40Ftdistunnel143510257645312321424215117B471,0152031221,340 TABLE B.9.SUSITNA DEVELOPMENT PLANS Cumulative Stage/Incremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $Millions On-line Full Supply Draw-Firm Avg.Factor (19BO values) 1 GWH.~ Plan Stage Construction Date Level -flo down-ft GWH • 1.1 1 Watana 2225 ft BOOMW 1B60 1993 2200 150 2670 3250 46 2 Devil Canyon 1470 ft 600 MW 1000 1996 1 4 5 0 100 5500 6230 51 TOTAL SYSTEM 1400 MW 2B60 00 I """0 1•2 1 Watana 2060 ft 400 MW 1570 1992 2000 100 1710 2110 60 2 Watana raise to 2225 ft 360 1995 2200 150 2670 2990 B5 3 Watana add 400 MW capacity 130 2 1995 2200 150 2670 3250 46 4 Devil Canyon 1470 ft 600 MW 1000 1 9 9 6 1 4 5 0 100 5500 6230 51 TOTAL SYSTEM 1400 MW 3ii6iJ 1.3 1 Watana 2225 ft 400 MW 1740 1 9 9 3 2200 150 2670 2990 B5 2 Watana add 400 MW capacity 150 1993 2200 150 2670 3250 46 3 Oevil Canyon 1470 ft 600 MW 1000 1996 1 4 5 0 100 5500 6230 51 TOTAL SYSTEM 1400 MW Ta9ii" TABLE B.9 (Continued) Cumulative Stage/Incremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $Millions On-line Full Supply Draw-Firm Avg.Factor Plan Construction (19BD values)1 GWH GWH ~Stage Date Level -ft.down-ft.• 2.1 1 High Devil Canyon 1775 ft BOO MW 1500 1994 3 1750 150 2460 3400 49 2 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 MW 2560 2.2 1 High Devil Canyon 0:>1630 ft 400 MW 1140 1993 3 1610 100 1770 2020 58I """2 High Devil Canyon~add 400 MW Capacity raise dam to 1775 ft 500 1996 1750 150 2460 3400 49 3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 MW 2700 2.3 1 High Devil Canyon 1775 ft 400 MW 1390 1994 3 1750 150 2400 2760 79 2 High Devil Canyon add 400 MW capacity 140 1994 1750 150 2460 3400 49 3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 MW 2590 3.1 1 Watana 2225 ft BOO MW 1860 1993 2200 150 2670 3250 46 2 Watana add 50 MW tunne I 330 MW 1500 1995 1475 4 4B90 5430 53 TOTAL SYSTEM 1180 MW 3360 ---- TABLE B.9 .(Continued) Cumulative Stage/Incremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $Millions On-line Full Supply Oraw-Firm Avg.Factor Plan Stage ConstrlJction (19BO values) 1Date Level -ft.down-ft.GWH GWH % 3.2 1 Watana 2225 ft 400 MW 1740 1993 2200 150 2670 2990 85 2 Watana add 400 MW capacity 150 1994 2200 150 2670 3250 46 3 Tunnel 330 MW add 50 MW to Watana 1500 1995 1 4 7 5 4 4890 5430 53 3390 ex>4.1 1 Watana I 1995 3..,.2225 Ft 400 MW 1740 2200 150 2670 2990 B5 N 2 Watana add 400 MW capacity 150 1996 2200 150 2670 3250 46 3 High Devil Canyon 1470 ft 400 MW B60 199B 1450 100 4520 52BO 50 4 Portage Creek 1030 ft 150 MW 650 2000 1020 50 5110 6000 51 TOT AL SYSTEM 1350 MW 3400 NOTES: (1)Allowing for a 3 year overlap construction period between major dams. (2)Plan 1.2 Stage 3 is less expensive than Plan 1.3 Stage 2 due to lower rrobilization costs. (3)Assumes FERC license can be filed by June 1984,ie.2 years later than for the Watana/Devil Canyon Plan 1. TABLEB.10-ENERGYSIMULATIONSENSITIVITYReservoirMaximumInstalledFullSupplyReservoirAnnualEnergy-GwhPlantCapacityLevelDrawdawnFactor1DevelopmentMWFeetFeetFirm(%)Average(%)%Watana2225FeetBOO22001002510(89)3210(101)45.880022001502670(94)3250(103)46.4BOO22001752770(98)3200(101)45.78002200Unlimited2830(100)3170(100)45.2Notes:(1)Secondlowestenergygeneratedduringsimulationperiod.8-43 TABLE 8.11.SUSITNA ENVIRONMENTAL OEVELOPMENT PLANS --------Cumulative Stage/lncremental Data System Data Annu8 [ Maximum Energy Capital Cost Earlip.st Reservoir Seasonal Product ion Plant $Mi lIions On-line Full Supply Draw-Firm Avg.Factor Plan (1980 values)1 ~ Stage Construction Date Level -ft.down-ft GWH GWH.~ E1.1 1 Watana 2225 ft 800MW and Re-Regutation Dam 1960 1993 2200 150 2670 3250 46 2 Devil Canyon 1470 ft 400MW 900 1996 1 4 5 0 100 5520 6070 58 TOTAL SYSTEI~1200MW '2llblr 00 E1.2 1 Watana 2060 ft 400MW 1570 1 9 9 2 2000 100 1710 2110 60 I 2 Watana raise to..,...,.2225 ft 360 1995 2200 150 2670 2 9 9 0 85 3 Watana add 400MW capaci ty and Re-Regulation Dam 230 2 1995 2200 150 2670 3250 46 4 Devil Canyon 1470 ft 400MW 900 1996 1450 100 5520 6070 58 TOTAL SYSTEM 1200MW J!lbIT E1.3 1 Watana 2225 ft 400MW 1740 1993 2200 150 2670 2990 85 2 Watana add 400MW capa~ity and Re-Regulation Dam 250 1993 2200 150 2670 3250 46 3 Devil Canyon 1470 ft 400 MW 9m 1996 1 4 5 0 100 5520 6070 58 TOTAL SYSTEM 1200MW wm TABLE 8.11 (Continued) Cumulative Stage/Incremental Data System Data Annua 1 Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $Millions Ill-line Ful!Supp 1y Draw-Firm Avg.Factor Plan Stage (1980 values)1ConstructionDate Level -fL down-fL GWH GWH % El.4 1 Watana 2225 ft 40DMW 1740 1993 2200 150 2670 2990 85 2 Devil Canyon 1470 ft 40DMW 900 1996 1450 100 5190 5670 81 TOTAL SYSTEM 80DMW 2640 E2.1 1 High Devil Canyon 1775 ft 80DMW and 00 Re-Regulation Dam 1600 1994 3 1750 150 2460 3400 49I """2 Vee 2350ft 40DMW 1060 1997 2330 150 3870 4910 47'-"TOTAL SYSTEM 1200MW 2660 E2.2 1 High Devil Canyon 1630 ft 400MW 1140 1993 3 1610 100 1770 2020 58 2 High Devil Canyon raise dam to 1775 ft add 40DMW and Re-ReglJlation Dam 600 1996 1750 150 2460 3400 49 3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 120DMW 2800 E2.3 1 High Devil Canyon 1775 ft 40DMW 1390 1994 3 1750 150 2400 2760 79 2 High Devil Canyon add 400MW capa~ity and Re-Regulation Dam 240 1995 1750 150 2460 3400 49 3 Vee 2350 ft 40DMW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 2690 TABLE B.11 (Continued) Cumu lat 1 ve Stage/Incremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $Mi llions On-line Full Supply Draw-Firm Avg.Factor Plan Stage Construction (19BO values)1Date Level -ft.down-ft.GWH GWH % E2.4 1 High Devil Canyon 1755 ft 40{l>\W 1390 19943 1750 150 2400 2760 79 2 High Devil Canyon add 400MW capacity and Portage Creek Dam 150 ft 790 1995 1750 150 3170 4080 49 3 Vee 2350 ft 400MW 1060 1997 2330 150 4430 5540 47 TOTAL SYSTEM TI"Iiil" 00 D.2 1 Watana I 2225 ft 40{l>\W 1740 1993 2200 150 2670 2990 85-0>en 2 Watana add 400 MW capacity and Re-Regul at ion Dam 250 1994 2200 150 2670 3250 46 3 Watana add 5fljW Tunnel Scheme 330MW 1500 1995 1475 4 4890 5430 53 TOTAL SYSTEM 1180MW mrr E4.1 1 Watana 2225 Ft 400MW 1740 1995 3 2200 150 2670 2990 85 2 Watana add 4~OMW capacity and Re-Regulation Dam 250 1996 2200 150 267fj 3250 46 3 High Devil Canyon 1470 ft 400MW 860 1998 1450 100 4520 5280 50 4 Portagp-Creek 1030 Ft 150MW 650 2000 1020 50 5110 6000 51 TOTAL SYSTEM 1350 MW >mIT NOTES: -m--Allowing for a 3 year overlap construction period between major dams. (2)Plan 1.2 Stage 3 is less expensive than Plan 1.3 Stage 2 dl.te to lower IOObilization costs. (3)Assumes FERC license can be filed by JIJne 1984,ie.2 years later than for the Watana/Devil Canyon Plan L TABLEB.12-ANNUALFIXEDCARRYINGCHARGESEconomicParametersTotalEconomicCostofAnnualLifeMoneyAmortizationInsuranceFixedCostProjectType-Vears%%%~~Thermal-GasTurbine(OilFired)203.003.720.256.97-Diesel,GasTurbine(GasFired)andLargeSteamTurbine303.002.100.255.35-SmallSteamTurbine353.001.650.254.90Hydropower503.000.B90.103.998-47 TABLE B.13 -RESULTS OF ECONOMIC ANALYSES OF SUSITNA PLANS -MEDIUM LOAD FORECAST Susltna Development Plan Inc.installed tapaclty (MW)by lota1 Systemlota1System Dnbne Dates Category in 2010 Installed Present Remarks Pertaining to Plan Stages OGP5 Run Iherme!Hydro Capacity In Worth Cos~the Susi tna Basin No.1 Z 3 4 Id.No.coal Gas 01.1 oEher Susltna 2010-MW $Million Development Plan E1.1 1993 2000 ----LXE7 300 426 0 144 1200 2070 5B50 E1.2 1992 1995 1997 2002 L5Y9 200 501 0 144 1200 2045 6030 E1.3 1993 1996 2000 --LBJ9 300 426 0 144 1200 2070 5850 1993 1996 ----L7W7 500 651 0 144 800 2095 6960 Stage 3,Devil Canyon Dam not constructed 1998 2001 2005 --LA07 400 276 30 144 1200 2050 6070 Delayed implementation schedule E1.4 1993 2000 ----LCK5 200 726 50 144 800 1920 5890 Total development limited to 800 MW Modified E2.1 1994 2000 ----L825 400 651 60 144 800 2055 6620 High Devil Canyon limited to 400 MW 00 E2.31 1993 1996 2000 --L601 300 651 20 144 1200 2315 6370I19931996LE075006513014480021256720 Stage 3,Vee Dam,not.po ---- 00 constructed Modified E2.3 1993 1996 2000 LEB3 300 726 220 144 1300 2690 6210 Vee dam replaced by Chakacharma dam 3.1 1993 1996 2000 --L607 200 651 30 144 1180 2205 6530 Special 3.1 1993 1996 2000 --L615 200 651 30 144 1180 2205 6230 Capital cost of tunnel reduced by 50 percent E4.1 1995 1996 1998 --LTZ5 200 576 30 144 1200 2150 6050 Stage 4 not constructed NOTES: (1)Adjusted to incorporate cost of re-regulation dam Remarks Pertaining to Plan Stages OGP5 Run Thermal Hydro Capacity In Worth Cost the Susitna Basin No.1 2 3 4 Id.No.Coal Gas oil Other Susitna 2010-MW $Million Development Plan VERY LOW FORECAST 1 El.4 1997 2005 ----L7B7 0 651 50 144 BOO 1645 3650 LOW LOAD FORECAST El.3 1993 1996 2000 ------------------Low energy demand does not warrant plan capacities El.4 1993 2002 ----LC07 0 351 40 144 BOO 1335 4350 1993 ------LBK7 200 501 BO 144 400 1325 4940 Stage 2,Devil Canyon Dam, not constructed E2.1 1993 2002 -- -- LG09 100 426 30 144 800 1500 4560 High Devil Canyon limited to 400 MW 1993 ------LBUl 400 501 0 144 400 1445 4850 Stage 2,Vee Dam,not 00 constructed I.po E2.3 1993 1996 2000 Low energy demand does notto------------------ warrant plan capacities Special 3.1 1993 1996 2000 --L613 0 576 20 144 780 1520 4730 Capital cost of tunnel reduced by 50 percent 3.2 1993 2002 ----L609 0 576 20 144 780 1520 5000 Stage 2,400 MW addition to Watana,not constructed HIGH LOAO FORECAST El.3 1993 1996 2000 --LA73 1000 951 0 144 1200 3295 10680 Modified 2005 2El.3 1993 1996 2000 L8V7 800 651 60 144 1700 3355 10050 Chakachamna hydroelectric generating station (480 MW) brought on line as a fourth stage E2.3 1993 1996 2000 --LBV3 1300 951 90 144 1200 3685 11720 Modified 2003 2E2.3 1993 1996 2000 LBY1 1000 876 10 144 1700 3730 11040 Chakachamna hydroelectric generating station (480 MW) brought on line as a fourth stage NOTE: (1)Incorporating load management and conservation -,-----"------------I TABLE 8.15 -ReSULTS OF ECONOMTC SENSITIVITY ANALYSES FOR GENERATrON SCENARIO INrORPORATING SUSITNA 8ASIN DEVELOPMENT PLAN E1.3 -MEDIUM FORECAST Iatal Iatal System System Installed Capacity (MW)by Installed Present Category in 2010 Capacity Worth Description Parameter OGP5 Run IhermaJ Hydro In 2010 Cost Parameter Varied Values Id.No.Coal Gas 011 Other Susltna MW $Million Remarks Interest Rate 5%LF85 300 426 0 144 1200 2070 4230 9%LF87 300 426 0 144 1200 2070 2690 Fuel Cost ($million Btu, natural gas/coal/oil)1.60/0.92/3.20 L533 100 576 20 144 1200 2040 5260 21)%fue 1 cost reduction Fuel Cost Escalation (%, natura 1 gas/coal/oil)0/0/0 L557 0 651 30 144 1200 2025 4360 Zero escalation 3.98/0/3.58 L563 300 426 0 144 1200 2070 5590 Zero coal cost escalation Economic Life of Thermal Plants (year,natural C')gas/coal/oil)45/45/30 L585 45 367 233 144 1200 1989 6100 Economic lives increased I by 50% <.n 0 Thermal Plant Capital Cost ($/kW,natural gas/ coal/oil)350/2135/778 LF.D7 300 426 0 144 1200 2070 5740 Coal capital cost reduced by 22% Watan~/Devil Canyon Capital Cost-($million,Watana/ Devil Canyon)1990/1110 L5G1 300 426 0 144 1200 2070 6210 Capital cost for Devil Canyon Dam increased by 23% 2976/1350 LD75 300 426 0 144 1200 2070 6810 Capital cost for both dams increased by 50% Probabilistic Load Forecast L8T5 200 1476 140 144 1200 3160 6290 NOTES: (1)Alaskan cost adjustment factor reduced from 1.8 to 1.4 (2)Excluding AFDC TA8LE8.16-ECONOMIC8ACKUPOATAFOREVALUATIONOFPLANSresenorasorPeriod$Million(%Total)GeneratlonPlanGeneratlonPlanWithWatana-WithWatana-DevilCanonDamTunnelAllThermalGenerationPlans2520(31}5240(64)370(5)8130(100)3020(46)340(5)3170(49)6530(100)330(6)2740(47)2780(47)5850(100)8-51350(6)2800(44)3220(50)o a6370(100)GeneratlonPlanWithHighOevilCanon-VeereraCJLonandMaintenance TABLE 8.17 -ECONOMIC EVALUATION OF DEVIL CANYON DAM AND TUNNEL SCHEMES AND WATANA/DEVIL CANYON AND HIGH DEVIL CANYON/VEE PLANS Remarks co I <.:n N ECONOMIC EVALUATION: -Base Case SENSITIVITY ANALYSES: -Load Growth -Capital Cost Estimate -Period of Economic Analysis Low High Period shortened to (1980 -2010) 680 650 N.A. Higher uncertainty assoc- iated with tunnel scheme. 230 520 210 1040 Higher uncertainty associated with H.D.C./Vee plan. 160 Economic ranking:Devil Canyon dam scheme is superior to Tunnel scheme.Watana/Devil Canyon dam plan is superior to the High Devil Canyon dam/Vee dam plan. The net benefit of the Watana/Devil Canyon plan remains positive for the range of load forecasts considered.No change in ranking. Higher cost uncertainties asSoci- ated with higher cost schemes/plans.Cost uncertainty therefore does not affect economic ranking. Shorter period of evaluation decreases economic differences. Ranking remains unchanged. -Discount Rate -Fuel Cost -Fuel Cost Escalation -Economic Thermal Plant Life 5% 8%(interpolated) 9% As both the capital and fuel costs associated with the tunnel 80%basic fuel cost scheme and H.D.C./Vee Plan are higher than for Watana/Devil Canyon plan any changes to these parameters cannot reduce the 0%fuel escalation Devil Canyon or Watana/Devil Canyon net benefit to below zero. 0%coal escalation 50%extension 0%extension Ranking remains unchanged. TABLE 8.18 -ENVIRONMENTAL EVALUAtION OF DEVIL CANYON OAM AND TUNNEL SCHEME Env ironment al Attribute Ecological: Concerns ApprsIsal 5cheme Judgedtonave (Differences in impact Identification the leaat potential impact of two schemes)of difference Appraisal Judgement funnel DC -Downstream fisheries and Wildlife Effects result ing from changes in water quantity and quality. r-.b significant differ- ence between schemes regarding effects down- st ream of Dev il Canyon. Di fference in reach bet ween Dev il Canyon dam and tunnel re- regulat ion dam. With the tunne1 scheme con- trolled flows between regula- tion dam and downstream power- house offers potent ial for anadromous f lsher ies enhsnce- ment in thie 11 mile reach of the river. r-.bt a factor in evaluat ion of scheme. If fisher ies enhancement oppor- tunity can be realized the tun- nel scheme offers a posit ive mitigation measure not available with the Devil Canyon dsm scheme.This opportunity is considered moderate and favors the tunnel scheme. Resident Fisheries:Loss of resident Minimal differences fisheries habitat.between schemes. c:> I (}l Wildlife:Loss of wildlife Minimal differencesWhabitat.between schemes. Devil Canyon dam would inundate 27 miles of the Susitna River and approximately 2 miles of Devil Creek.The tunnel scheme would inundate 16 miles of the Susitna River. The most sensitive wildlife ha- bitat in this reach is upatream of the tunne 1 re-regulation dam where there is no significant difference between the schemes. The Dev il Canyon dam scheme in addition inundates the river valley between the two dam sites reSUlting in a moderate increase in impacts to wildlife. This reach of river is not con- sidered to be highly significant for resident fisher ies and thus the difference between the schemes is minor and favors the tunnel scheme. The di fference in loss of wild- life habitat is considered mod- erate and favors the tunne I scheme. x x Cultural: Land Use: Inundation of archeological sites. lnundat ion 0 f Dev il Canyon. Potential differences bet ween schemes. Significant difference bet ween schemes. Due to the larger area inun- dated the probabil ity of inun- dating archeological sites is increased. The Dev H Canyon is considered a unique resource,80 percent of which wouid be inundated by the Devil Canyon dam scheme. This would result in a loss of both an aesthet ic value plus the potential for white water recreat ion. A aignificant archeological site,if identified,can proba- bly be excavated.This concern is not cona idered a factor in in acheme evaluation. The aesthet ic and to some extent the recreat ionaI lossea associ- ated with the development of the Devil Canyon dam is the main aspect favoring the tunnel acheme. x OVERALL EVALUATION,The tunnel scheme has overall a lower impact on the environment. TABLE 8.19 -SOCIAL EVALUATION OF SUSITNA BASIN DEVELOPMENT SCHEMES/PLANS SoClal-------~---Tunnel Devll Canyon High Devil Canyon!Watana!DeVll Aspect Parameter SChElI1!~l2am_Scheme __Vee Plan Canyon Plan Remarks All projects would have similar impacts on the state and local economy. Potential non-renewable resource displacement Impact on state economy Impact on local economy Million tons Be luga coal over 50 years ] 80 110 170 .. 210 Devil Canyon dam scheme potential higher than tunne I scheme.Watana/ Devil Canyon plan higher than High Devil Canyon/ Vee plan. 00 I (Jl -I::> Seismic exposure Risk of major structural failure Potential impact of failure on human life. All projects designed to similar levels of safety. Any dam failures would effect the same downstream population. Essentially no difference between plans/schemes. Overall Evaluation 1.Devil Canyon dam superior to tunnel. 2.Watana/Devil Canyon superior to High Devil Canyon/Vee plan. 8-55TABLE8.20-ENERGYCONTRIBUTIONEVALUATIONOFTHEDEVILCANYONDAMANDTUNNELSCHEMESRemarksDevilCanyonschemesdevelopsmoreofthebasinpotentia1.DevilCanyondamannuallydevelops610GWHand540GWHmoreaverageandfirmenergyrespectivelythantheTunnelscheme.Ascurrentlyenvisaged,theDevilCanyondamdoesnotdevelop15ftgrossheadbetweentheWatanasiteandtheDevilCanyonreservsoir.Thetunnelschemeincorporatesaddi-tionalfrictionlossesintunneIs.Alsothecompen-sationflowreleasedfromre-regulationdamisnotusedinconjunctionwithheadbetweenre-regulationdamandDevilCanyon.3238020502240lunnel436028502590DamParameterNotes:TotalEnergyProductionCapabllityAnnualAverageEnergyGWHFirmAnnualEnergyGWH%BasinP~tentialDevelopedEnerryPotentialNotDeveopedGWH(1)Basedonannualaverageenergy.FullpotentialbasedonUSSRfourdamscheme. TABLE8.21-OVERALLEVALUATIONOFTUNNELSCHEMEANDDEVILCANYONDAMSCHEMEAliRIBOtEEconomicEnergyContributionEnvironmentalSocialOverallEvaluationSUPERIORpLANDevilCanyonDamDevilCanyonDamTunnelDevilCanyonDam(Marginal)DevilCanyondamschemeissuperiorTradeoffsmade:Economicadvantageofdamschemeisjudgedtooutweig,thereducedenvironmentalimpactassociatedwiththetunnelscheme.8-56 TABLE B.22 -ENVIRONMENTAL EVALUATION OF WATANA/DEVIL CANYON AND HIGH DEVIL CANYON/VEE DEVELOPMENT PLANS Environmental Attribute Plan Comparison ....Appraisal Judgement Plan Juoged to tia"e tlie least potential i""act HOC7V .--WlOC co I (J1 '-l ECOlorical: 1}lsheries 2)Wildlife a)Moose b)Caribeu c)Furbearers d)Bi rds and 8ears ~: No significant difference in effects on downstream anadromous fisheries. HOC/V would inundate approximately 95 miles of the Susitna River and 2B miles of tributary streama,in- cluding the Tyone River. W/OC would inundate approximately 84 miles of the Susitna River and 24 mi les of tributary streams, including WaLana Creek. IfOC/V would inundate 123 mi les of critical winter river bottom habitat. W!De would inondate 108 miles of this river botlom habitat. IlDe/V would inundate a large area upstream of Vee utilized by three sub-populations of moose that range in the northeast aection of Lhe basin. W!De would inundate the Watana Creek area uti lized by moose.The condition of this sub-population of mooae and the quality of the habitat they are using appears to be decreasing. The increased length of river flooded,eapecially up- sLream from the Vee dam sHe,would result in the IlDe/V plan creating a greater potential di vision of the Nelchina herd's range.In addition,an increase in range would be directly inundated by the Vee res- ervoir. The area flooded by the Vee reservoir is considered important to some key furbearers,particularly red fox. This area is judged to be more important than the Watana Creek area that would be inundated by the W/OC plan. Forest habitat,important for birds and black bears, exist along the valley slopes.The losa of this habi- t at would be greater with the W!De plan. There is a high potential for discovery of archeologi- cal sites in the easterly region of the Upper Susitna 8asin.The HOC/V plan has a greater potential of affecting these sites.For other reaches of the ri ver the difference between plans is considered minimal. Due to the avoidance of the Tyone River, lesser inundation of resident fisheries habitat snd no significant difference in the effects on anadroffiOus fisheries,the w/rJC plan is judged to have less impact. Due to the lower potential for direct impact on mooae populations within the Susitna,the W/De plan is judged superior. f)Je to the potential for a greater impact on the Nelchina caribou herd,the IlOC/V acheme is considered inferlor. Due to the lesser potential for impact on fur- bearers the W/OC is judged to be superior. The IlOC/V plan is judged superior. The W!De plan is judged to have a lower po- tential effect on archeological aites. x x x x x ,. TABLE B.22 (Continued) Environmentsl Attribute Plan Compsrison Apprsisal Judgement PTBi1-rooged to have tfie least potential impact HOC7V-W70C Aesthetic! Land Use With either scheme,the aesthetic quality of both Devil Canyon and Vee Canyon would be impai red.The HDC!V plan would also inundate Tsusena falla. Due to construction at Vee Dam aite and the size of the Vee Reservoir,the HOC!V plan would inherently create access to more wilderness area t.han would the W!OC plan. Both plans impact the valley aesthetics.The difference is considered minimal. As it ia easier to extend secess than to limit it,inherent access requirementa were considered detrimenta I and the W!DC plan is judged superior.The ecological sensitivity of the area opened by the HDC!V plan re in- forces this judgement. x co I U1 CO OVERAl.L EVALUATION:The W!DC plan is judged to be superior to the HDC!V plan. (The lower impact on birds and bears associated with HDC!V plan is considered to be outweighed by all the other impacts which favour the W!DC plan.) NOTES: W =Watana Dam OC =Dev il Canyon Dam HOC =High Devil Canyon Dam V =Vee Dam 8-59TABLE8.23-ENERGYCONTRIBUTIONEVALUATIONOFTHEWATANA/DEVILCANYONANDHIGHDEVILCANYON/VEEPLANS(1)Basedonannualaverageenergy.FullpotentiaIbasedonUSBRfourdamschemes.(2)Includeslossesduetounutilizedhead.RemarksWatana/DevilCanyonplandevelopsmoreofthebasinpotentialAscurrentlycon-ceived,theWatana/-DevilCanyonPlandoesnotdevelop15ftofgrossheadbetweentheWatanasiteandtheDevilCanyonreservoir.TheHighDevilCanyon/VeePlandoesnotdevelop175ftgrossheadbetweenVeesiteandHighDevilreservoir.Watana/DevilCanyonplanannuallydevel-ops1160GWHand1650GWHmoreaverageandfirmenergyre-pectivelythantheHighDevilCanyon/VeePlan.6508149103870HighDevilCanyon/Vee916860705520Watana!DevilCanyonParameterNotes:EnerryPotentialNotDeveopedGWH(2)%BasinPotentialDeveloped(1)TotalEnergyProductionCapabilityAnnualAverageEnergyGWHFirmAnnua1EnergyGWH TABLE8.24-OVERALLEVALUATIONOFTHEHIGHDEVILCANYON/VEEANDWATANA/DEVILCANYONDAMPLANSAiIRIBO/£EconomicEnergyContributionEnvironmentalSocialOverallEvaluationSuPERiORPLANWatana/DevilCanyonWatana/DevilCanyonWatana/DevilCanyonWatana/DeviICanyon(Marginal)PlanwithWatana/OevilCanyonissuperiorTradeoffsmade:None8-60 TABLE 8.25 -RESULTS OF ECONOMIC ANALYSES FOR GENERATION SCENARIO INCORPORATING THERMAL OEVELOPMENT PLAN -MEOIUM FORECAST lotal System 10ta1 Installed Capacity (MW)Installed System by Category in 2010 Capacity Present Description Parameter OGP5 Run Thermal In 2010 Worth Cost Parameter Varled Value Id.No.Coal Gas 011 Hydro Total MW $Million Remarks Interest Rate 5%LEA9 900 800 50 144 1895 5170 9%LEB1 900 801 50 144 1895 2610 Fuel Cost ($million Btu, natural gas/coal/oil)1.60/0.92/3.20 L1K7 BOO B76 70 144 1890 7070 20%fuel cost redlJction Fuel Cost Escalation (%, natural gas/coal/oil)0/0/0 L547 0 1701 10 144 1B55 4560 Zero escalation 3.98/0/3.58 L561 1100 726 10 144 1980 6920 Zero coal cost escalation Economic Life of Thermal Plants (year~natural 45/45/30gas/coal/oil L5B3 1145 667 51 144 2007 7B50 Economic life increased CO 511%•I 0\Thermal Plant Capital Cost ($/kW,natural gas/350/2135/778 LAL9 1100 726 10 144 1980 7590 Coa 1 capital cost reduced coa l/oil)by 22% TABLE 8.26 -ECONOMIC SENSITIVITY OF COMPARISON OF GENERATION PLAN WITH WATANA/DEVIL CANYON AND THE ALL THERMAL PLAN Present worth of Net Benefit ($million)of total generation system costs-for the Watana/Devil Canyon plan over the all thermal plan. l'Eiramele~rs--------------sens1.tIvTEy-Ana I ys:eS-JJi:esenE wortht:$mITI ion)Remarks co I 0) N LOAD GROWTH CAPITAL COST ESTIMATE PERIOD OF ECONOMIC ANALYSIS DISCOUNT RATE FUEL COST FUEL COST ESCALATION 5 ECONOMIC THERMAL PLANT LIFE Notes: Very low Low Medium High Low Thermal Cost 2 High 3Hydroelectric Cost 1980 -2040 1980 -2010 30',0 5% 8%(interpolated) 9 0',0 Low 4 0%escalation for all fuels m~escalation for coal only 50%extension to all thermal plant life 1280 1570 2280 2840 1850 1320 2280 960 2280 940 o -80 1810 200 1330 1800 The net benefit of the Watana/Devil Canyon Plan re- mains positive for the range of load forecasts con- sidered. System costs relatively insensitive.Capital cost estimating lJ1certainty does not effect economic ranking. Shorter period of evaluation decreases economic dif- ferences.Ranking remains unchanged. Below discount rate of 8%the Watana/Devil Canyon plan is economically superior. Watana/Devil Canyon plan remains economically super- ior for wide range of flrel prices and escalation rates. Economic benefit for Watana/Devil Canyon plan rela- tively insensitive to extended thermal plan economic life. (1)All parameters,except load growth,tested using medium load forecast. (2)Thermal capital cost decreased by 22%. (3)Estimated Susitna cost increased by 50~~. (4)All fuel costs reduced by 20%.Base case costs $/million Btu:Coal 1.15,Gas 2.00,Oil 4.00 (5)Base case escalation:Coal 2.93%,Gas 3.98%,Oil 3.58%. A1T Thermal lieneratlon Plan wl.th Social Aspect JParam~ter Generation Plan Watana/Devil Canyon Remarks Potential non-renewable resource displacement Impact on state economy Impact on local economy Million tons of Beluga coal,over 50 years Direct &Indirect employment and in- come. Business investment. Gradually,contin- uousl y growing impact. 210 Potentially more dis- rupt i ve impact on economics. With Watana/Devil Canyon plan is superior. Available information insufficient to draw definite conclusions. Se ismic exposure Risk of major structural failure All projects designed to similar levels of safety. Both scenarios judged to be equal. 0::> Imw Potential impact of fai lure on human life. Failure wou ld effect only operating per- sonnel.Forecast of failure would be im- possible. Failure would effect larger number of people located downstream, however,some degree of forecasting dam fai lure would be impossible. Overall No significant difference in terms of ComlJ_l:jrisOIl ..overall assessment ~lans. TABLE8.28-GENERICCOMPARISONOFENVIRONMENTALIMPACTSOFASUSITNABASINHYDRODEVELOPMENTVERSUSCOALFIREDTHERMALGENERATIONINTHEBELUGACOALFIELDSEnvironmentalAttributesEcological:Cultural:Aesthetic/LandUse:ConcernsSusltnaBasinDevelopmentPotentialimpactonfisheriesduetoalterationofdown-steamflowdistributionandwaterquality.InundationofMooseandfurbearerhabitatandpotentialimpactonCariboumigration.Nomajorairqualityproblems,onlyminormicroclimaticchangeswouldoccur.Inundationofarcheologicalsites.Inundationoflargeareaandsurfacedisturbanceincon-structionarea.Createsaddi-tionalaccesstowildernessareas,reducesriverrecrea-tionbutincreaseslakerec-reationalactivities.8-64ThermalGenerationPotentialforimpactonfisheriesresultingfromwaterqualityimpairmentoflocalstreamsandlocalhabitatdestructionduetosurfacedisturbancesbothatmineandgeneratingfacili-ties.Impactonairqualityduetoemissionofparticu-lates502,NO,tracemetalsandwa~ervapoursfromgeneratingfacilities.Potentialdestructionofarcheologicalsites.Surfacedisturbanceoflargeareasassociatedwithcoalminingandthermalgenera-tionfacilities.Createsadditionalaccessandmayrestrictlanduseactivi-ties. -----'--"-'"""""""'"'"--_.._----------------------TABLE8.29-OVERALLEVALUATIONOFALLTHERMALGENERATIONPLANSWITHTHEGENERATIONPLANINCORPORATINGWATANA/DEVILCANYONDAMSAl1RIBUTEEconomicEnvironmentalSocialOverallEvaluationSUPERIORpLANWithWatana/DevilCanyonUnabIetodistinguishdifferenceinthisstudyduetositespecificnatureofimpactsNosignificantoveralldifferencePlanwithWatana/DevilCanyonisjudgedtobesuperiorTradeoffsmade:Notfullyexplored8-65 ::;) I G 0, PREVIOUS STUDIES AND FIELD RECONNAISSANCE SCREEN ENGINEERING LAYOUT AND COST STU DI ES COMPUTER MODELS TO DETERMINE LEAST COST DAM COMBINATIONS 3 BASIC DEVELOP- MENT PLANS DATA ON DIFFERENT THERMAL GENERATING SOURCES I ---II COMPUTER MODELS I TO EVALUATE -POWER AND ENERGY YIELDS -SYSTEMWIDE ECONOMICS CRITERIA ECONOMIC ENVIRONMENTAL SOCIAL ENERGY CONTRIBUTION WATANA I DEVIL CANYON PLUS THERMAL LEGEND ~STEP NUMBER IN STANDARD PROCESS (APPENDIX A) ADDITIONAL SITES PORTAGE CREEK DiS HIGH DEVIL CANYON DiS WATANA OBJECTIVE ECONOMIC WATANA I DEVIL CANYON I I HIGH DEVIL CANYON I VEE HIGH DEVIL CANYON /WATANA CRITERIA DEVIL CANYON ECONOMICS HIGH DEVIL ENVIRONMENTAL CANYON ALTERNATIVE WATANA SITES SUSITNA m ENERGY VEE CONTRIBUTION MACLAREN DENALI GOLD CREEK DEVI L CANYON HIGH DEVIL CANYON DEVIL CREEK WATANA SUSITNA ill VEE MACLAREN DENALI BUTTE CREEK TYONE SUSITNA BASIN PLAN FORMULATION AND SELECTION PROCESS FIGURE 8.1 • OSHETNA RIVER /'I 1 2500' 'i 1 2 00 0 ' ..... H <[ Z I- Ci) :::l C/)-- ----=r-r-TYONE RIVERF-l...J 2000' :~MACLAREN I ~2200' RIVER C:J I (J) '-J >:FI I I ijj I U Z <[0::I :i LLJ )<[I I <[I- U «1905'-z ...J I «I- PORTAGE CR.~Z~~z l-I u Z :::l«Ci)LLJ /<[LLJ 2535'~o >u I-205Ol :::l LLJ ::::E I 0 >-LLJ ~C/)>~2350'I 23951'z 0 C/)4 «::t::=!2200'I U <.!)>+.-.-....J LLJ.~>::t:0 1750'L2300' 0::C/)/LLJ ~5/0 .--1450' gS70,Jj ~200 220 240 260 2S0 1000' _oJf/I#'"102d--I 500'• 000' 500' 000' 500' 100 120 140 160 ISO RIVER MILES ~ PROFILE THROUGH ALTERNATIVE SITES FIGURE 8.2 [11m I DAM IN COLUMN IS MUTUALLY EXCLUSIVE IF FULL SUPPLY LEVEL OF DAM IN ROW EXCEEDS THIS VALUE-FT. VALUE IN BRACKET REFERS TO APPROXIMATE DAM HEIGHT. BUTTE CREEK TYONEBUTTE CREEK TYONE MACLAREN I DENALI DENALI WATANA I SUSITNAml VEE MACLAREN VEE DEVIL CREEK SUSITNA m WATANA DEVIL CREEK HIGH DEVIL CANYON DEVI L CANYO N OLSON COMPATIBLE ALTERNATIVES MUTUALLY EXCLUSIVE ALTERNATIVES D GOLD CREEK co I 0'>co MUTUALLY EXCLUSIVE DEVELOPMENT ALTERNATIVES FIGURE 83 [110 I 500015004000FIGURE8.4LEGEND•COSTDEVELOPEDDIRECTLYFROMENGINEERINGLAYOUTSCOSTBASEDONADJUSTMENTSTOoVALUESDETERMINEDFROMLAYOUTS10008-69100020003000RESERVOIRSTORAGE(103xAF)HIGHDEVILCANYON011-----'-----'-----'-----'-----'--_o15001000800WQ600)(.-tn4000u20000DEVILCANYON1000Wo><.-t-(f)0u500DAMSITECOSTVSRESERVOIRSTORAGECURVES LEGEND•COSTDEVELOPEDDIRECTLYFROMENGINEERINGLAYOUTSCOSTBASEDONADJUSTMENTSTOoVALUESDETERMINEDFROMLAYOUTS13901860oJ'-...L-..I-.l..1-'-I_...1000200030004000RESERVOIRSTORAGE(103xAF)SUSITNAIIT1000U)g)('*~(J)0u500DAMSITECOSTVSRESERVOIRSTORAGECURVES15008-70FIGURE8.5o"--_---J.__--J...__"'--_---J.__...l-__"'--_---J.__•o2000400060008000100001200014000RESERVOIRSTORAGE(103xAF)WATANA24002000400800~~1200u-<f1600 80050004401060LEGEND•COSTDEVELOPEDDIRECTLYFROMENGINEERINGLAYOUTSCOSTBASEDONADJUSTMENTSTOoVALUESDETERMINEDFROMLAYOUTS1000200030004000RESERVOIRSTORAGE(103xAF)DENALI/500~8001000200I-(J)8400t;400o()2008-71800O'--_--"__-J...__...L-__J...-_--J.__--'-__.......-..o200400600800100012001400RESERVOIRSTORAGE(103xAF)VEE200FIGURE8.6O'--_--L.__...J...__....I...-__l..-_--l.__....__..l.-...o200400600800100012001400RESERVOIRSTORAGE(103xAF)MACLAREN=600l!>Q)(--~400I-(J)o()~600)(~ciJ600QxDAMSITECOSTVSRESERVOIRSTORAGECURVES 4.3.2.I.TUNNELSCHEME#"300MW365MW1150MWDEVILCANYON550MW-_.RE-REGULATIONDAM30MW2TUNNELS24FT.DIAMETER38FT.DIAMETERFIGURE8.78-722TUNNELS30FT.DIAMETER800MW38FT.DIAMETER2TUNNELS800MW800MW--.850MW15.8MILESI_-J-,--_1475FT.'V",--800MW-70MWt-2MILESy--1475FT.RE-REGULATIONDAMSCHEMATICREPRESENTATIONOFCONCEPTUALTUNNELSCHEMES2200FT.WATANA'V 10001----------------------+-----------t----i60008.8[i].5000E3.2QI3IIIIII/200030004000AVERAGEANNUALENERGY-GWH8-73FIGURECAPITALCOSTVERSUSENERGYPLOTSFORENVIRONMENTALSUSITNABASINPLANS1000LEGENDSTAGEISTAGE2o0PLANEI0---0PLANE2~---~PLANE3o-._.~PLANE4oL------L..----....I.-----.l-------L..------L-.l--_..Jo 2010DEVILCANYON(400MW)WATANA-I(400MW)2000EXISTINGaCOMMITTED13422059TIME1990oHYDROELECTRICltt:ttlCOALFIREDTHERMALEZ:JGASFIREDTHERMAL•OILFIREDTHERMAL(NOTSHOWNONENERGYDIAGRAM)NOTE:RESULTSOBTAINEDFROMOGPSRUNL8J9PEAKLOADLEGEND:948FIGUREI"L7Ll.GENERATIONSCENARIOWITHSUSITNAPLANE1.3-MEDIUMLOADFORECAST-TOTALDISPATCHEDENERGY19807152oLI0~3~··~···=··~·..l.~54L-3.U=d~..b=d-3_0_0J1:\\::\ill:::\:rg:::::ig:\:\:L19801990200020102486301.---..1.------------------------------_....... OL....._-.L.--I223020102010a.lo.·.VEE(400MW)HIGHDEVILCANYON-2(400MW)HIGHDEVILCANYON-1(400MW)2000EXISTINGANDCOMMITTEDTIMEFIGURE8-75199019721949I406!-L-"-'-l1990DHYDROELECTRICI:rrrriCOALFIREDTHERMALEZlGASFIREDTHERMAL•OILFIREDTHERMAL(NOTSHOWNONENERGYDIAGRAM)NOTE:RESULTSOBTAINEDFROMOGPSRUNL60IPEAKLOAD,,\LEGEND:GENERATIONSCENARIOWITHSUSITNAPLANE2.3-MEDIUMLOADFORECAST-TOTALDISPATCHEDENERGY~19801980228 oL---J..----------------------....l20101338201911111111J11....19898.11.WATANA-2(400MW)TUNNEL(380MW)1726WATANA- I(400MW)2000EXISTINGaCOMMITTEDTIME1990DHYDROELECTRICftrrr:lCOALFIREDTHERMALEllGASFIREDTHERMAL•OILFIREDTHERMAL(NOTSHOWNONENERGYDIAGRAM)NOTE:RESULTSOBTAINEDFROMOGPSRUNL607LEGEND'FIGUREGENERATIONSCENARIOWITHSUSITNAPLANE3.1-MEDIUMLOADFORECAST-TOTALDISPATCHEDENERGY~198071562810o~12:03:.t~~..§5.i4.12...b~d---.i4.§.5..6=d-..:2:0:.:°Jjr~E:r:j{:.ill.:{:19801990200020103~2ooo>-t-Ori:1<!o 1272201020108818.12[iii]1232DEVILCANYON(400MW)WATANA(400MW)11572000....."'"""i589EXISTINGaCOMMITTEDHYDROTIMEFIGURE8-7719901079NOTE:RESULTSOBTAINEDFROMOGPSRUNLC07DHYDROELECTRICItttt:lCOALFIREDTHERMALDGASFIREDTHERMAL712GENERATIONSCENARIOWITHSUSITNAPLANE1.5-LOWLOADFORECAST-1980948LEGEND:28OL----L--------------------------..I4~~103oL-E:::['::":[::::::]:::::l::.25i4~CZZJL±47Lj'm·'·'.;m·,.;·;m·'·;·;:l·,.;~4:±2..J.._-l1980199020006.41.2 201020108.13[j]1000DEVILCANYON(400MW)WATANA-I(400MW)WATANA-2(400MW)445238420001990TIME8-78FIGURESCENAR10WITHSUSITNAPLANE1.3HIGHLOADFORECASTDHYDROELECTRICtItttlCOALFIREDTHERMALE]GASFIREDTHERMAL•OILFIREDTHERMAL(NOTSHOWNONENERGYDIAGRAM)NOTE:RESULTSOBTAINEDFROMOGPSRUNLA73715103GENERATIONTOTALDISPATCHEDENERGY19801980948L__.§~~~gg~~~g!~~~~~~:I:EX~11STTII~NGLJa[Jc~0~M[fiM[jITEJT]EQD========::jo2000:::::{{:{{1450w.l.::t.....tl:=:::=-----------l~~L---_19903.53248164123LEGEND:I>-I-oit«01:I:~(DoooI8>-(!)a::wzw 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PROJECTouuASSHOWNSK'.'5700-Clr1oeAX'....'",r·..\)\\,\\)~{poOSTILLINGet>SINrAVG.Tl..1LWATER.~EL.'2.405'~IGAttDEC.1981""Aft"".''_0DENALIaMACLARENHYDRODEVELOPMENTSALASKAPOWERAUTHORITY$U$ITNAItYDROEI.ECTRICPLATE7CROSSSECTION(/4-II;,'x::''2'Wl-lEE.LSMOUNTE.DGATESECTIOND·DSGALE.:CDAMDENALIGENERALARRANGEMENTSCALE:A00.~~E.BE.LLMOUTl-lTEMPOI<ARYOPFOR.DIVEQ510NEtJ1DAlENOJ<.MAL.MAX..SOOE~=s;~W'C.C~154~'~'0_~5Q~'~~~.=~5'<=ESToCMOS'2'00ROCK,,"L~FILTER1.!5~ROCkF1LL.IMPE.RVIOUS\,-SEMI-PERVIOUS..ILTER.SCAL.E.A0400I800FEETSCAt.E.E:>0200400FE.E.TSCALE:C0I100.00FEE.T,A-ASECTIONNORMALMl>.'>(rW.L.E.L.'Z.~95·':cRE.STE.L.'2400',--2400/SC.ALE.:C4NORMALMAXW.L.EL.'2,.,95;SCALE.:AI<OGKFILL~15'01p...STEELCLlLVI:RT5;;;;-----NC12E.T£SURROUND-EL.'2405'MAlN.OA.M--GENMACLARE.NERALARRANGE.MENT!IUPPER./RE5EK'VOIJ<...t...EVE.1./COFFERDAM(/'2.450/-'2.5002500DRAINAGE.STILLINGBASIN-2200c~~M'A'T".'R';IA~C~~~;=~~~=:::~:::::~==::=~:.~~:::~:""'-:~"""~'~TAJ~LW'.:=~EL.'2.~'SE.CTIONB·Bnoo"------~--=~§~~FIL.TE12E5ROCKm,-SEMI-PERviOUSFILTE.Q..DAMCROSS70>1"'2400 PREFERREDTUNNELSCHEME3PLANVIEWSALASKAPOWERAUTHORITY8GUIITNAHYDROIELECTRIC""OJ.EeTPLATEII\\IIII"IIII"'0'01ASU~E.T.o.NJ<.S\IIIII,~L.-.--'2.~dOIA.\~POWE.,",=TUNNE.L'5\\II\I\\II\I,II1\\I\\\\IIGENERAL.ARRANGEMENTPEVILCANYONR::>WERf-lOlJSESCALE0400800FEETI'DAn110.NOTE'ALLPLANSANDL.AYOUTSFORCONCE.PTUALSTUDYPURPOSe;.01-11..'(.NORMALtW,L,"'12GoO'PL.AN~RE-!<.EGULATJONDAM~-~R'SCl-1EME':>SCALE~O~""""""liiiiiiiiiii~2MILE.i!GOOFE.ET300SCALE0GENERALARRA~GEMENIRE-REGULATIONDAM----==::::==-===--=====-==-==-==----=.=========INTAlLE.~-------~L.IFTGAlE.5--------~------------_____.__--......SPlL.I..WA,'1'CREST__________EL.143&'.........._-J--"-...___---j/....1700noo,c;oo--- KAUASSHOWNS'K:'57oo-cs·n"....DEC.1981PREFERREDTUNNELSCHEME3SECTIONSSUSITNAHYDftOEL£CTRICt'nOJ£CT200FEE.T!ALASKAPOWERAUTHORITY9PLATESCA.l.e.A 0100BlOTlT-GRANOORITE00.TRA.NSFOR.MER.GALLE.RYNOTE.'Al-LSTRUC.TURALANDStJPPORTDETA.ILSARECONCEPTUALPNDFOR.STUDYPURPOSE,::>ONLY.SCALE.:ADEVILCANYONPOWERFACILITIESPROFILE5DISTA.NCE.INMll..E.STUNNE.LALIGNMENT---------------------FA~TSETTJIlGOR""/G~UTA'SRE.QUIR£.D(T"R)~T~:-DE.TAIL-e;DRILLHOll!:W.W-F.STEE.J.PL....T£HEXNUTFA':.TSETTtm.GROUT"oL__~__L__.L__.L__.L__..L__..L___l.._____L_____l_____l___l_____l_____lL__L__L__L__L~_,,~>-'"'"2~~~Z0~I~OO~~W,~oACCESSArlITo-ORIF=lC.E-------SURGETANI<.__DETAILS(T'fP.)ROCKBOLTS4SHOTCRETE1SHOTCRETE'-.,""__(NOTTOsCAt..E)ROCKBOLTSIGOO150014""ww~~1300%~~1'100>w~w11001000.00TYPICALTUNNELSECTIONSI·ROClC.BOl.TflITY!':1DETAILA.CTf?,)STEELSETWJ'l.F.SHOTCIlETECRe.:STe:U500'\\.\--"':"'<~_COARSEfilTERI/f---\.\\..FlNEFILTER'---~''ROLlEO~KAll,;ROm!>IMPalVIOllSGORE.'~f.:;''f"'•SE.CTIONA·AClSTIIIPLN:ECONCRETE1I1l1~M,l,X.O'IiRATJN6lliVELII..J"'"~'4OW~40HVE'itrICALUFTGATESEl..143:'-----------I»TAKE.G,o;rt'[7f1-A ALeEMINGpM)CONC.LINEDw/STEELSETTWHRAeSCALE.;ASeAl-E.:A.SPILLWAYPROFILERE-REGULATIONDAMTYPICALSECTIONPOWERTUNNELINTAKESECTIONSCA.LE.;A.----/NORMALMAX.EU<l-1S'MIN.NOll:l.1A\.OPWTIHGLEvelEL.JA70'""'::----"""""''''''.--------------Ilf.-~~-,,<~ROUTCURTAINUNLINEDTYPICALTUNNELSECTIONS(NOTTO"ACE)''''""1"0014'"130014""00"00"",00'"00"00'40'"00KAUASSHOWNS'K:'57oo-cs·n"....DEC.1981PREFERREDTUNNELSCHEME3SECTIONSSUSITNAHYDftOEL£CTRICt'nOJ£CT200FEE.T!ALASKAPOWERAUTHORITY9PLATESCA.l.e.A0100BlOTlT-GRANOORITE00.TRA.NSFOR.MER.GALLE.RYNOTE.'Al-LSTRUC.TURALANDStJPPORTDETA.ILSARECONCEPTUALPNDFOR.STUDYPURPOSE,::>ONLY.SCALE.:ADEVILCANYONPOWERFACILITIESPROFILE5DISTA.NCE.INMll..E.STUNNE.LALIGNMENT---------------------FA~TSETTJIlG"""/G~UTA'SRE.QUIR£.D(T"R)~T~:-DE.TAIL-e;DRILLHOll!:W.W-F.STEE.J.PL....T£HEXNUTFA':.TSETTtm.GROUT"oL__~__L__.L__.L__.L__..L__..L___l.._____L_____l_____l___l_____l_____lL__L__L__L__L~_,,~>-'"'"2~~~Z0~I~OO~~W,~oACCESSArlITo-ORIF=lC.E-------SURGETANI<.__DETAILS(T'fP.)ROCKBOLTS4SHOTCRETE1SHOTCRETE,\""__(NOTTOsCAt..E)ROCKBOLTSIGOO150014""ww~~1300%~~1'100>w~w11001000.00TYPICALTUNNELSECTIONSI·ROClC.BOl.TflITY!':1DETAILA.CTf?,)STEELSETWJ'l.F.SHOTCIlETECRe.:STe:U500'\\.\--"':"'<~_COARSEfilTERI/f---\.\\..FlNEFILTER'---~''ROLlEO~KAll,;ROm!>IMPalVIOllSGORE.'~f.:;''f"'•SE.CTIONA·AClSTIIIPLN:ECONCRETE1I1l1~M,l,X.O'IiRATJN6lliVELII..J"'"~'4OW~40HVE'itrICALUFTGATESEl..143:'-----------I»TAKE.G,o;rt'[7f1-A ALeEMINGpM)CONC.LINEDw/STEELSETTWHRAeSCALE.;ASeAl-E.:A.SPILLWAYPROFILERE-REGULATIONDAMTYPICALSECTIONPOWERTUNNELINTAKESECTIONSCA.LE.;A.----/NORMALMAX.EU<l-1S'MIN.NOll:l.1A\.OPWTIHGLEvelEL.JA70'""'::----"""""''''''.--------------Ilf.-~~-,,<~ROUTCURTAINUNLINEDTYPICALTUNNELSECTIONS(NOTTO"ACE)''''""1"0014'"130014""00"00"",00'"00"00'40'"00 ~------------~--SUSITNAHYDRDELECTRICDEVELOPMENTestudiesdiscussedinprevioussectionsofthisreportconcludethat,onthesisoftheanalysestodate,thefuturedevelopmentofRailbeltelectricpowernerationsourcesshouldincludeaSusitnaHydroelectric-Project.Furtherworkrequiredtofullyestab1ishthetechnica1andeconomicfeasibi1ityofthel)Sitnaprojectandtorefineitsdesign.Theprojectascurrentlyconceivedisscribedinthissection.t-SelectedPlandescribedinSection8,theselectedSusitnaBasindevelopmentplaninvolveseconstructionoftheWatanadamtoacreste1evationof2225feetwitha400powerhousescheduledtocommenceoperationby1993.ThisdateistheDliestthataprojectofthismagnitudecanbebroughton-line.Adelayinisdatewouldmeanthatadditionalthermalunitswouldhavetobebroughton71ineresultinginanincreaseinthecostofpowertotheconsumer.Thisrststagewouldbefollowedbyexpandingthepowerhousecapacityto800MWbyQ96andpossiblytheconstructionofare-regulationdamdownstrearntoallowilypeakingoperations.Moredetailedenvironmentalstudiesarerequiredtoghfirrntherequirementforthisre-regulationdamanditmaybepossibletoQcorporateitintheDevilCanyondamdiversionfacilities.Thefinalstage01vestheconstructionoftheDevilCanyondarntoacreste1evationof1465twithaninstalledcapacityof400MWbytheyear2000.Ouldtheloadgrowthoccuratalowerratethanthecurrentrnediurnforecast,enconsiderationshouldbegiventopostponingthecapacityexpansionproposedWatanaandtheconstructionoftheDevilCanyondamtotheyear2002orpos-si.91yeven2005.These1attertwodatescorrespondrespectivelytotheloviloadrecastandtheextremelowforecastincorporatinganincreasedlevelofloadnagementandconservation.Foractualloadgrowthrateshigherthanthediumloadforecasts,constructionoftheDevilCanyondamcouldbeadvancedto98.~houghithasbeendeterminedthatthisdevelopmentplanisextremelyeconomicawiderangeofpossiblefutureenergygrowthrates,theactualschedulingBthevariousstagesshouldbecontinuouslyreassessedon,say,afiveyear~is.Itshouldalsobestressedthatthedamheightsandinstalledcapacitiesotedaboveareessentiallyrepresentativeordersofmagnitudeatthisstageofojectplanning.Thesekeyparametersaresubjecttomodificationasthemoretailedprojectoptimizationstudiesareconductedduring1981.ThedarntypeTectedfortheDevilCanyondarnsitehascurrentlybeenrevisedfromtheckfillalternativedescribedinSection8toathindouble-curvatureconcretetshdarn.Moredetailedengineeringstudiescarriedoutsubsequenttothe~nningstudiesdescribedhaveindicatedthisdarntypetobemoreappropriatethesiteconditionsaswellasslightlymorecosteffective.TheresultsofeseengineeringstudiesarecontainedinAppendixH.ProjectDescriptiont;thisstageinthedevelopmentofoptimumprojectdesigns,variousalternativeoject1ayoutsarebeingproducedforboththeWatanaandDevilCanyonsites.~eselayoutsarebeingcomparedfrombothtechnicalandeconomicviewpointsandqiscomparisonwillleadtotheselectionofpossiblytwoorthreebasicyoutsateachsiteforstudyinmoredetail.9-1 Atthisearlystagecertainlayoutsarediscernedtobemoreattractivethantheircounterparts.Ofthese,asinglelayoutateachoftheWatanaandDevilCanyonsiteshasbeenselectedasrepresentativeofthepossiblefinaldeveloment,andisdescribedinthissection.Theselayoutsareindicativeofthepresentstageofthestudy.Muchfield"isstillplannedtogetherwithdesignandrefinementstudies,andtheselayoushouldonnoaccountberegardedasthefinaldevelopmentsatthistime.(a)Watana(Plates12and13)(i)SiteGeologyThedamsiteatWatanaisunderlainbyadioriticintrusion(plutcThesitehasafavorableconfigurationbecausetheriverhascutcthroughtheintrusion,resultinginanarrowcanyon.Theplutoniboundedattheupstreamanddownstreamedgesbysedimentaryrocksthatshowevidenceofbeingdeformedandarchedupwardsbytheplutonicintrusion(Figure7.4).Theevidencetodateindicatestthesedimentaryrockhasbeenerodedfromthetopoftheplutonattheimmediatesite.Followingintrusion,atintervalsthathaveryetbeendetermined,volcanicseruptedintothearea.ThesevolcanicsformthebasaltflowsexposedinthecanyonnearFogCrEdownstreamofthesite,andtheandesiteflowsovertheplutonatdamsite.Thereisnoindicationofbasaltflowswithintheimmediatedamsite,buttheandesitehasbeendetectedinseveralboringsinthewesternportionofthesite.Thenatureandcharacteristicsofthediorite-andesitecontactwillbefurtherinvestigatedinthe1981program.Thesurficialmaterialatthedamsiteispredominantlytalusandverythinglacialsedimentsontheabutments,withlimiteddeposiofriveralluviumandlakeclayatisolatedlocations.Theriverchannelisfilledwithupto80feetofalluvialdepositsderivedfromtillandtalusmaterial.Thedrillingandseismiclinesindcatethatthebedrockweatheringaveragestentotwentyfeet,witlverydistinctgradationfromweatheredtounweatheredrock.Theficialweatheringprocessesseemtobeprimarilyphysicalratherchemical.Bedrockqualitybelow60feetisuniformtothemaximuldepthsdrilled.Thepatternofsound,unweatheredrockzonesareseparatedbyshearzonesofrockalteredbyinjectionoffelsiteandesitedikes,withsubsequentdeteriorationofthebrokenrockgroundwater.Thebasicconditionsarefavorabletoconstructionbothsurfaceandundergroundstructures,withremedialtreatmentlikelytobelimitedtoshearzones.(ii)GeotechnicalAspectsTheWatanadamsiteliespredominantlyonsounddioritewhilesomportionsofthedownstreamshelloverlayandesite.Theupper1040feetofrockisweathered.Theseismicconsiderationsforthesite,asdiscussedinSection7,indicatethattherelativelyuncpactedalluvium(upto80feetindepth)wouldhavetoberemovedfromunderneathmostofthedam.Inaddition,itisassumedthat9-2 p-orktsn).ownshatlot!ekthe:si-1a;ur-:hannandly)fetoom-upto40feetofrockexcavationwillberequiredundertheimperviouscoreandthesupportingfilterstofoundthedamonsoundcompetentrock.Thistypeoffoundationpreparationisconsiderednormalforlargedamsofcomparablesize.Shearzonesandjointswithintherockfoundationhavebeenlocatedandwillrequireconsolidationandcurtaingrouting.Thesefeaturesmayalsonecessitatetheinclusionofdrainagefeatureswithinthefoundationandtheabutmentsasindi-catedinthepresentarrangement.Permafrostispresentontheleftabutmentandmayalsobepresentundertheriverchannel.Thedataindicatesthatthisis"warm"permafrostandcanbeeconomicallythawedforgrouting.Adeeprelictchannelexistsontherightbankupstreamofthedam.Theoverburdenwithinthisrelictchannelcontainsasequenceofglacialtillandoutwashinterlayeredwithsiltsandclaysofglacialorigin.Thetopofrockundertherelictchannelareawillbebelowthereservoirlevel.Furtherinvestigationswillbeundertakentopreciselydefinethecharacteristicsofthechannel.However,thedatacollectedtodatedoesnotindicatethatitwillhaveanymajorimpactonthefeasibilityofthesite.Therockconditionsintheleftbank,wheretheundergroundpower-houseiscurrentlyproposed,arefavorable,andthepowerhousecavernwillrequireonlynominalsupport.However,additionalinvestiga-tionswillbeconductedtodeterminetheexactlocationandorienta-tionofthefeatures,soastominimizetheimpactofjointsandanypossibleunfavorablestressorientation.Materialsforconstructionofafilldamandrelatedconcretestruc-turesareavailablewithineconomicdistances.Imperviousandsemi-perviouscoreandfiltermaterialsareavailablewithinthreemilesupstreamofthesite,(Figure7.4)andagoodsourceoffiltermater-ialandconcreteaggregateisavailableatthemouthofTsusenaCreekjustdownstreamofthedam.Rockfillisavailablefromaquarrysourceimmediatelyadjacenttoleftabutmentofthedamandfromstructureexcavations.Thereisalsoapossibilityofusingroundedriverbedmateria1forthedamshellsifadequatequantitiesareavailable.Furtherinvestigationswi11beconductedtobetterdefinethequantityandcharacteristicsofmaterialineachsourceareaandtherelativeeconomicsofeachborrowlocation.(iii)DamThemaindamisanearth/rockfillstructure\'/iththemajorityofthematerialsexcavatedfromselectedborrowareas,butwithasmallportionderivedfromexcavationforthestructuresattheprojectsite.Thecompactedimpervioustillcoreisprotectedupstreamanddownstreambygravelfilterandtransitionzonesandsupportedbyshellsformedfromcompactedlayersofblastedrockandgravelmaterials.Themaximumheightofthedamabovethefoundationisapproximately880feet,thecrestelevationis2,225feetandthedevelopedcrestlengthis5400feet.Thecrestwidthis80feet,theupstreamanddownstreamslopesare1:2.75and1:2respectivelyandtheoverallvolumeofthedamiscurrentlyestimatedasapproximately9-3 9-463millioncubicyards.Thedamisfoundedonsoundbedrock.Upstreamanddownstreamcofferdamsarefoundedontheriveralluviumandintegratedwiththemaindam.(vi)PowerFacilities-Intakeofarock/earthfillCutoffbeneaththecof-Theintakeissituatedupstreamoftherightabutmentofthedam.ItissetdeepwithintherockandissimilarinstructuretotheDevilCanyonintakewithprovisionfordrawingoffwateratdiffer-entlevelswithinthefluctuatingreservoir.Duringconstruction,theriverisdivertedthroughtwoconcrete-linedtunnelsdrivenwithintherockoftheleftabutment.Thetunnelsaresetlowandwillflowfullatalltimes.Upstreamcontrolstructuresatthetunnelinletswillregulateflowstomaintainanearconstantwaterlevelinthereservoirandallowformationofastableicecoverandtopreventicebuildupwithinthetunnelinlets.Controlwillbeaffectedbyverticalfixedwellgateshousedwithintheup-streamstructures.Thesewillalsobeutilizedforfinalclosuretogetherwithmassconcreteplugsconstructedwithinthetunnelsinalignmentwiththedamgroutcurtain.Theriverwillbedivertedupstreambymeanscofferdamfoundedontheriverbedalluvium.ferdamisformedbyaslurrytrenchtorock.Thespillwayislocatedontherightbankanddesignedtopasstherouted1:10,000yearfrequencydesignfloodofapproximately115,000cfswithoutdamagetoanyoftheprojectstructures.Thespillwayisalsocapableofpassingflowsofupto230,000cfscorrespondingtotheprobablymaximumfloodatWatana.Thiswouldrequireareservoirsurchargeupto5feetbelowthedamcrestlevel.Duringpassageofthismajorfloodsomedamagetothespillwaychuteanddischargestructuresandsomedownstreamerosionwithintherivervalleywouldbeaccepted.Thespillwayconsistsofagatestructure,withthreeverticalfixedwheelcontrolgates,aconcretelinedchuteandaflipbucket,simi-lartothatatDevilCanyon(Section9.2(b)),dischargingintoadownstreamplungepoolexcavatedfromthealluviumwithintheriver-bed.(v)SpillwayAlowlyingareaabovetherightabutmentisclosedwithanapproxim-ately25foothighimperviousfillsaddledam.(iv)Diversion -PenstocksFourconcrete-linedtunnelpenstocksdescendataninclinationof55'andterminateinsteellinersatthepowerhousefeedingthehighpressureturbines.-PowerhouseThepowerhousecomplexissimilartothatforDevilCanyonwithseparatepowerhouseandtransformerbaycaverns.Themaincavernhousesfour200MWturbine/generatorunitsconsistingofverticallymountedFrancisturbinesdrivingoverheadumbrellatypegeneratorsservicedbythemainoverheadcrane.Majorofficesandthecontrolroomareincorporatedintheadministrationbuildingatthesurface.Anelevatordescendsfromthisbuildingtoprovidepersonnelaccesstothepowerhouse.Vehicleaccesstothepowerhouseandtransformergalleryisbyunlinedrocktunnelleadingfromthebottomofthevalley.-TailraceTheturbinedrafttubetunnelsleadfromthepowerhousetoacommonmanifoldsupplyingasinglepartly-linedtailracetunnelwhichemerges,belowriverlevel,downstreamofthemaindam.(vii)DownstreamReleasesAtthepresenttimethereisprovlslonmadeforemergencydrawdownoftheWatanareservoir.Thiswilltaketheformofanintermediatelevelreservoiroutlet.Flowsarecontrolledbyhighpressuregateslocatedinanundergroundchamber,andaconcrete-linedtunneldischargesintothediversiontunnel,downstreamoftheconcreteplug.Smallreleases,duringshutdownofthegeneratingplant,aremadeviaasmalldiversionincorporatedwiththeundergroundcontrolstructure.(b)Devi1Canyon(Plates10and11)(i)SiteGeologyDevilCanyonisaverynarrowV-shapedcanyoncutthroughrelativelyhomogeneousargilliteandgraywacke.Thisrockwasformedbylow-grademetamorphismofmarineshales,mudstones,andclayeysand-stones.Thebeddingstrikesabout15'northeastoftheriveralign-mentthroughthecanyonanddipsatabout65'tothesouthwest.Therockhasbeendeformedandmoderatelyshearedbythenorthwestactingregionaltectonicforces,causingshearingandjointingparalleltothisforce(Figure7.4).Theglaciationofthepastfewmillionyearsapparentlyprecededtheerosionofthecanyonbytheriver.GlacialdepositsblanketthevalleyabovetheV-shapedcanyon,whiledepositsinthecanyonitselfarelimitedtoalargegravelbarjustupstreamofthecanyonentrance,andboulderandtalusdepositsatthebaseofthecanyonwalls.9-5 BedrockconditionsatDevilCanyonvarywithinalimitedrangeduetochangesoflithology,buttherockisbasicallysoundandfairlydurable.Jointingandshearsarefrequentlyquiteopenatthesurface,butthereisageneraltighteningofsuchopeningswithdepth.ThemajorjointsetstrikesaboutNorth30°Westacrossthecanyon,andmaybeanindicationofshearzonesinthisdirection.TwominorsetsstrikeroughlyNorth60-90°East,withdipsofabout50-60°southand15°south.Theorientationofthejoints,andparticularlytheshearzones,isnotwelldefined.Furtherfieldmappingin1981shouldclarifythis.(ii)GeotechnicalAspectsTheDevilCanyondamsiteliesonargilliteandgraywackeexhibitingsignificantjointingandfrequentshearzones.Thenatureoftherockissuchthatnumerouszonesofgouge,alteration,andfracturedrockwerecausedduringthemajortectoniceventsofthepast,inadditiontothefoldingandinternalslippageduringlithificationandmetamorphism.Consequently,zonesofdeepweatheringandaltera-tioncanbeexpectedinthefoundation.Excavationofupto40feetofrockwillexposesoundfoundationrock,andconsolidationgroutinganddentalexcavationofbadlycrushedandalteredrockwillbenec-essarytoprovideadequatebearingsurfacesforthedam.OverburdenwithinthenarrowV-sectionofthevalleyisminimal.Theleftbankplateau,whichisthelocationofasaddledam,hasaburiedriverchannelparallelingtheriver.Theoverburdenreaches90feetunderasmalllakeinthisareaandconstructionofthesaddledamwillrequireexcavationofconsiderableamountsoftillandlakedepositsorconstructionofacutoffextendingdowntobedrock.Seepagecontrolwillbeeffectedbytwomethods:first,bygeneralcontactandconsolidationgroutingtocontrolflowatthedamfoundationcontact,andsecondbyadeepgroutcurtainwithcorrespondingdrainagecurtaintolimitdownstreamflowthroughthe.foundation.Permafrosthasnotbeendetectedatthesitebut,ifitdoesexist,itisnotexpectedtobesubstantialorwidespread.Athawingprogramcanbeincorporatedinconjunctionwiththegroutingifnecessary..Constructionmaterialsareavailableinthelargegravelbarimmedi-atelyupstreamofthedamsite.Thematerialsinthisbarareestimatedtobeadequateinquantityforallmaterialneedsoftheconcretedam.The1akebedandtilldepositsinCheechakoCreek(approximately0.25milesupstream),maybesourcesofasubstantialportionofimperviousmaterialfortheearthfi11saddledam.(iii)DamThemaindamiscurrentlyproposedasathinconcretearchstructurewithanoverallheightof650feetanddevelopedcrestlengthof1,230feet.Thecrestwidthis20feetandthebasewidthatthecrowncanti1everis90feet.Thegeometryofthearchcorrespondstoatwocenterconfigurationwhichiscompatiblewiththeassymetrictransverseprofileofthevalley.9-6 Thecentralsectionofthedamrestsonamassiveconcreteplug,foundeddeepwithinthevalleyfloorandtheupperarchesterminateinthrustblockslocatedhighontheabutments.Aconcretewallextends4feetabovetheupstreamedgeofthecresttoallowadditionalsurchargeduringpassageoftheprobablemaximumflood.Alowlyingareaontheleftabutmentisfilledbyasaddledam.Thesaddledamisarockfillstructurewithanimperviouscore.Itabutsandsurroundstheconcretethrustblockwiththecorewrappingtheconcretetoprovideaseal.Overburdenwillbeexcavatedtoallowthecoretobefoundedonthedeepunderlyingbedrock.Acontinuousgroutcurtainanddrainagesystemisprovidedbeneaththemainandsaddledamslinkingwithsimilarsystemsupstreamofthepowerhouseandbeneaththemainspillway.Groutanddrainageholesaredrivenfromaseriesofinterconnectingshaftsandgallerieswhichwillallowcontinuedaccessbeneaththefoundationsofthedam.(iv)DiversionRiverdiversionduringconstructionissimilartodiversionforWatanawithtwinconcrete-linedtunnelsandupstreamcontrolstructures.Cofferdamsareasdescribedpreviously.FulluseofstorageatWatanawillbeusedtosafeguardconstructionatDevilCanyon.(v)SpillwaysThemainservicespillwayislocatedontherightabutmentandisdesignedforflowsofupto90,000cfs.Dischargesarecontrolledbythreeverticalfixedwheelgateshousedinaconcreteoverflowstruc-tureincorporatedinarightthrustblock.Flowsarerouteddownasteeplyinclined'concretelinedchute,foundedwithinsoundbedrock,anddischargeoveraflipbucketintotheriver.Theflipbucketisamassiveconcretestructurecontiguouswiththechute.Itimpartsaverticalvelocitycomponenttothedischarges,trainingthemalongauniformlycurvedinvertandejectingtheminabroadshallowjetintotheriverwelldownstreamofthedam.Alluviumwithintheriverisremovedtobedrockinthevicinityoftheareaofimpactofthedis-chargejet.Asecondaryspillwaysystemdesignedtodischarge40,000cfsispro-videdwithinthedamintheformoffoursubmergedorificeshighinitscentersection.Theseorificesarecontrolledby15feetx15feetverticalliftgatesanddischargesarethrownclearofthedamintoadownstreamplungepoolexcavatedintherockbeneaththeexis-tingriverbed.Thecombinationoftheabovespillwaysissufficienttopasstherouted1:10,000yearfrequencydesignfloodof130,000cfs.Greaterdischargesarepossiblebyallowingsurchargeofthereservoirtothelevelofthedamcrestwavewall.9-7 Beyondtherockfillsaddledamontheleftabutmentachannelisexcavatedintherockandrunsapproximately1,400feetdownstreamdischargingintoatributaryvalleytothemainriver.Thechannelisclosedbyanimperviousfillfuseplugwhichcanbeovertoppedduringexcessivefloodsandwillwashout,probablyaftersomelocalexcavationhasbeencarriedout,tothefullsectionoftherockchannel.Dischargedownthischannelplussurchargeoverthemainspillwayswillallowforpassingofthefullprobablemaximumfloodintheunlikelyeventthatthisshouldevertakeplace.(vi)PowerFacilities-IntakeTheintakeislocatedupstreamoftherightabutmentofthedam.ItisamassiveconcretestructuresetdeepinthebedrockattheendofashortupstreampO~lercanaLTheintakeisformedoffouradjacentunits,eachwiththecapabilityofdrawingoffwateratlevelsthroughoutandbelowa150feetrangeofdrawdownwithinthereservoir.Theselevelsarecontrolledbylargeverticalshuttersoperatingintwosetsofguidessetonebehindtheother.Byrais-ingandloweringtheshutters,openingscanbecreatedbyvaryinglevelsovertheheightofthestructure.Theseshutterswillnotoperateunderpressureasclosureoftheintakeswillbeperformedbyverticalfixedwheelgatessetdownstreamoftheshutters.-PenstocksFourconcretelinedtunnelpenstocksleadfromtheintakeanddes-cendatanangleofinclinationof55°tohorizontaltotheunder-groundpowerhouse.Justupstreamofthepowerhousetheliningchangestosteelinordertopreventseepageintothemainpowercavernandtocontainthehighinternalpressuresinthevicinityofthefracturedrockcausedbyblastingthepowerhouseexcava-tion.-PowerhouseThepowerhousecomplexconsistsoftwomainexcavations;themainpowercavernhousingthegeneratingunitsservicebayandmainten-anceareas,andthetransformeranddrafttubegategallery.Themaincavernhousesfour100MWturbine/generatorunits.TheturbinesareverticallymountedFrancistypeunitsdrivingoverheadumbrellatypegeneratorsservicedbyanoverheadcranetravellingthelengthofthepowerhallandendservicebay.Switchgear,minoroffices,serviceareasandaworkshoparehousedinthisarea.Upstreambusductgalleriesareinclinedfromgeneratorfloorlevelatthepowercaverntothetransformergalleryrunningthelengthofthepowerhouseandsetabovethepenstocks.Verticalshaftsareraisedfromthedrafttubestothedownstreamsideofthepower-houseandtheseincorporateverticalguidesfortheoperationofclosuregateswithinthedrafttubesandfunctionassurgeshaftsduringchangesofflowwithinthetailrace.9-8 9-9Downstreamofthegates,thedrafttubesmergeintoasingleconcretelinedtailracetunnelwhichwillbesetbelowriverlevelandwillflowfullatalltimes.inclinedrocktunnelPersonnelaccessisbypowerhousecavernandVehicleaccesstothepowerhouseisviaandrivenfromthebottomoftherivergorge.meansofanelevatoroperatingbetweenthetheadministrationbuilding.-TailraceCableshaftsrisefromthetransformergallerytothesurfaceandthepowerlinesarecarriedfromtheseacrossthedamtotheswitchyardontheleftabutment.Thecontrolroomandmainadministrationbuildingislocatedatthesurface.AsshowninFigure9.1,itisexpectedtotakeapproximately11yearstocompleteconstructionoftheWatanadamfromthestartofanaccessroadtothetestingandcommissioningofallthegeneratingunits.Principalcom-ponentsofthescheduleincludeapproximately3yearsofsiteandlocalaccess,1-1/2yearsforriverdiversionandmostoftheremainingtimeforfoundationpreparationandembankmentplacement.Thisperiodcomparesto15yearsestimatedintheCOE1979report.ThemostimportantdifferencesthattheCOEprovidedfora4-1/2yearperiodofaccessroadconstructionpriortoanyworkbeingdoneatthesite.Inthisstudy,becauseoftheAtthisstageofthestudy,apreliminaryassessmentoftheconstructionsched-ulesfortheWatanaandDevilCanyondamshasbeenmade.Themainobjectivehasbeentoprovideareasonableestimateofon-linedatesforthegenerationplanningstudiesdescribedinSection8.Moredetailedconstructionscheduleswillbedevelopedduringthe1981studies.(vii)DownstreamReleasesReleasesdownstreamduringshutdownofthepowerplantwillbemadethroughHowellBungervalvessetclosetothebaseofthedamanddischargingfreelyintotherivervalley.9.3-ConstructionSchedulesIndevelopingthesepreliminaryschedules,roughly70majorconstructionactivi-tieswereidentifiedandtheapplicablequantitiessuchasexcavation,borrowandconcretevolumesweredetermined.Constructiondurationswerethenestimat-edusinghistoricalrecordsasbackupandtheexpertiseofseniorscheduler-planners,estimatorsanddesignstaff.Acriticalpathlogicdiagramwasdevelopedfromthoseactivitiesandtheprojectdurationwasdetermined.Thecriticalornearcriticalactivitydurationswerefurtherreviewedandrefinedasneeded.Theseconstructionlogicdiagramsarecodedsothattheymaybeincorporatedintoacomputerizedsystemforthemoredetailedstudiestobecon-ductedduring1981.Theschedulesdevelopedaredescribedbelow:(a)WatanaRockfi11Dam economicadvantagetobegainedfromanearlyon-linedate,a"fasttracapproachhasbeenadoptedduringtheearlystagesofconstruction.Thisinvolvesoverlandwinteraccessandextensiveaircraftsupporttotheeaactivitiesassociatedwithconstructionofthediversionsystemandabutmentexcavationforthemaindam.Onlyaboutsixmonthsperyearcanbeusedforfillplacementduetosnoandtemperatureconditions.Fillplacementrateshavebeenestimatedatbetween2.5and3.0millioncubicyardspermonth.Thisissomewhathigthanthe1979COEfigureof2.4millioncubicyardspermonthplacementoverafive-monthannualplacementperiod.Ithasbeenjudgedthattheearlyon-linedatewouldjustifytheimplementationofconstructionsystwithhigherproductionrates.Itisexpectedthattherivercanbeim-poundedasconstructionproceedssoastominimizethetimelagbetweencompletionofthedamembankmentandthetestingandcommissioningoft~firstpowerunit.ThescheduleshowstheearliestdatepowerproductionfromtheWatanadicouldstartwouldbeJanuary1993.Thisisbasedonstartingconstruct;ofaccessroadsinearly1985assoonastheFERClicenseisreceived.(b)DevilCanyonThinArchDamAsshowninFigure9.2,itwilltakeapproximately9yearstocomplete!damfromthestartofconstructingaccesstothesitetothetestinganicommissioningofthepowerunits.AsfarasconstructionofthedamisconcernedthisscheduleagreeswiththatdevelopedbytheCOE.Itdoeshowever,incorporateanadditional1-1/2yearsforconstructionofamaaccessroadfromtheWatanasite.Thekeyelementsindeterminingtheoverallschedulearetheconstructiofdiversiontunnels,cofferdams,theexcavationandpreparationofthefoundationandtheplacementoftheconcretedam.Forpurposesofestiingactivitydurations,itisassumedthatembankmentandcurtaingroutwi11.bedonethroughverticalaccessshaftsoneachembankment.(c)InterpretationofSchedulesTheattachedfiguresrepresentan"earlystart"scheduleandthemajoriofthestudyefforttodatehasbeenexpendedindeterminingthe"critipath"whichcontrolsprojectduration.Duringthecontinuing1981stucthe"non-critical"itemswi11bescheduledtotakeintoaccountresourcavailabilityandfinancialandclimaticaspects.Thiswillresultint"non-critical"itemsbeingmorerigidlyscheduledthanisshownintheattachedfigures.9.4-OperationalAspectsSection8outlinestheresultsofthepowerandenergyevaluationsforthese1ectedplan.Thissectionsupplementstheinformationandillustratessorthemonthlyreservoirsimulationresultsandhighlightsthedownstreamflowcharacteristicswhichareimportantfromanenvironmentalpointofview.9-10 <"rlwheremsthee1mon:heI•innat-ingtyca1ieseheleofFigures9.3through9.5illustratetheoperationofthereservoirsforatypical30yearperiod.Figure9.1showsthemonthlyenergyproduction,inflow,out-flows,andwaterlevelsfortheStage1Watana400MWdevelopment.Figures9.4and9.5illustratesimilarresultsforthefinalfullydevelopedtwodamscheme.Thereservoirshavebeenassumedtobeoperatedtoproducemonthlyenergypro-ductionthatfollowsthesamegeneralshapeastheseasonalpatternofthetotalRailbeltelectricitydemand.Duringthesummermonths,particularlyduringlatesummerwhenthereservoirstendtobefull,additionalorsecondaryenergyisgeneratedinordertoutilizesomeofthewaterthatwouldotherwisebespilled.Thesecondaryenergyproductionandspillageisclearlyillustrated.ThefiguresindicatethatduringStage1theWatanaspillwaywouldbeoperated8outofevery10yearsandthatin7oftheseyears,flowwouldbedischargedfor2ormoremonths.Oncethetotaldevelopmentiscompleted,thespillwayswouldonlybeoperatedforroughly2-1/2yearsoutof10andmostofthetimeforaperiodoflessthanamonthinagivenyear.Atthisstageofdevelopment,theDevilCanyonspillwaywouldbeoperated7outof10years,andduring3oftheseyearsspillwouldoccurfor2ormoremonths.Tables9.1to9.3summarizetypicaloutflowsfromthedownstreamdaminthepreferreddevelopment.Theseflowsincludewatercomingfromtheturbinesandwaterpassingoverthespillway.ItwillbenotedthatdailyfluctuationsarekepttoaminimumfortheWatana400MWdevelopment.OutflowsfromtheDevilCanyondaminthefulldevelopmentplanalsoshowlimitedfluctuations.However,fortheStage2400MWcapacityadditionatWatanasubstantialdailyfluctuationsdooccurandmayrequiredownstreamregulation.9.5-EnvironmentalReviewTheenvironmentalinputintotheSusitnastudieshastwomajorcomponents;miti-gationplanningandimpactidentification.Mitigationplanningincludesavoid-ance,reduction,andcompensation.InparticipatingintheSusitnadevelopmentselection,ourobjectivewastoidentifywhatdevelopmentscheme(s)wasmosten-vironmentallycompatable,thus,avoidingmanypotentialimpacts.Inaddition,designfeatureswererecommendedtoreducepotentialimpactsevenifthemostcompatablesiteswereselected.Identifyingcompensationmeasuresandtheac-tualpredictionofenvironmentalimpactsarethesubjectofongoingstudies.Theresultsofthesestudieswillbeincludedinour1982feasibilityreporttobeavailablepriortomakingthedecisionastowhetherornottoproceedwithFERClicensing.(a)EnvironmentalAspectsTheUpperSusitnaBasinhasbeenconsideredasapotentialhydroelectricdevelopmentsitenotonlybecauseoftheeconomicsandenergypotentialbutalsobecauseofitsrelativecompatabilitywiththeenvironment.Comparedtootherpotentiallargehydrodevelopmentsites(e.g.RampartontheYukonRiverorMillionDollarontheCopperRiver).TheUpperSusitnahaslesspotentialenvironmentalimpact.AcomparisonofalternativestoSusitnaisoutsidetherealmofthesestudies,however,theyarebeingfullyassessedinaparallelstudybeingconductedbyBatelle.9-11 Aswithanytypeofmajordevelopment,hydroelectricprojectscancauseanhaveelsewherecausedsignificantenvironmentalimpacts.Inregardtore-ducingoreliminatingenvironmentalimpacts,probablythemostimportantfactoristheselectionofadevelopmentplanthatisbasicallyasinher-entlycompatiblewiththeenvironmentaspossible.Retrofittypemitiga-tionmeasureswhichareoftenofminimalsuccessandusuallyverycostlyareundesirable.Developmentcharacteristicsthathavecausedproblemsonotherhydropro-jectsthatarenotinherenttoSusitnainclude:-Thediversionofmajorrivers.-Thedirectblockageofanadromousfishmigrationduetothebarriercreatedbythedam.Theamplificationofflowregulationproblemscausedbyhavingaseriesofreservoirswithminimalstorageandpoorspillwaydesign.-Inundationoflargeareasofprimewildlifehabitat.Thus,althoughtheSusitnaHydroelectricProjectstillhasthepotentialccreatingenvironmentalimpacts,manyofthemajorpotentialimpactsoftenassociatedwithhydroelectricdevelopmentsareavoidedbytheselectionoftheUpperSusitnaBasin.ForstudieswithintheSusitnaBasinitisstillimportantthatenvironmertalinputstillbeprovidedintothedecisionmakingprocess.Todate,ttmajorenvironmentalimputintotheSusitnastudieshasbeendirectedto-wardsevaluationofalternatives,recommendationofdesignfeatures,estallishmentofoperatinglimitsforplanningpurposes,andthecollectionofbaselinedata.Themajorenvironmentalobjectivesareto(1)ensurethatenvironmentalcompatibilityisincorporatedasaprinciplefactorindeveopmentselectionanddesign,and(2)topresentaclearpictureoftheen·vironmentalconsequencesofdevelopingthefinalselectedscheme.PartsIobjective(1)arepresentedinthisreportwhereanenvironmentalcompari·sonofalternativeSusitnadevelopmentsispresented.Theproductofob-jective(2)willbecontainedintheenvironmentalsectionofthefeasibiityreportpreparedattheendofPhaseIstudies.Itmustbenotedthatalthoughenvironmentalcompatibilityhasbeenincorporatedasadesirableobjective,itisnotasolefactorinthedecisionmakingprocess.Theinterrogationofeconomicviability,technicalfeasibility,andenvironmentalacceptabilityhavenecessitatedjudgementsandtradeoffs.Tofacilitatearationalassessment,thesejudgementsandtradeoffshavebeendefinedasclearlyaspossible.Insomeinstances,economicandenvironmentalpreferencesrecommendedsimilaraction;anexamplebeingtheWatana/DevilCanyonplanwherethereservoirsarebasicallyconfinedtotherivervalley.Inotherinstancesaspecificdecisiohasbeenmadethataneconomicexpenditureisrequiredtoretainenviron-mentalcompatibility;examplesbeingmultilevelintakestructurestoalloforsometemperaturecontrolofdischargewaterandtheprovisionfordo~streamdailyre-regulationofflows.Instillotherinstances,theeconoicexpenditurewasnotconsideredwarrantedtoreduceoravoidresultant9-12 f1-1-)f1-nNn-m-(b)environmentalimpacts;anexamplebeingatunnelschemeatacostof$680milliontoavoidtheinundationoftheupstreamportionofDevilCanyon.Asdesignstudiesprogress,continuedenvironmentalimpactassessmentswillbeincorporated.Anenvironmentalassessmentoftheselectedschemewillbeincorporatedintothefinalfeasibilityreport.ThisreportwillbemadeavailableforgovernmentagencyandpublicreviewpriortomakingadecisionastowhetherornottoproceedwithFERClicenseapplication.In1975(updatedin1979)theCOEproducedanEnvironmentalImpactState-mentontheWatana/DevilCanyonDevelopment.TheinformationgatheredbytheCOEinthisstudyisbeingenhancedbyinsightobtainedfromthe1980studiesandinareaswherestudyeffortiscontinuingaspartofthepre-sentstudy.HydrologyUnderexistingconditionsseasonalvariationofflowsintheSusitnaisex-treme.AtGoldCreektheaveragewinterandsummerflowsare2,100and20,250cfsrespectively,a 1to10ratio.Withregulateddischargeresult-ingfromahydroelectricdevelopment,downstreamflowsbetweenDevilCanyonandtheconfluenceoftheTalkeetna/Chulitnariverswillberelativelycon-stant.Figures9.3-9.5showthedifferencesbetweeninflowsandoutflowsandtheoccurrenceofspillingwiththeprojectatvariousstagesofdevel-opment.Thesechangesinflowwillbeattenuateddownstreamduetotheun-alteredinflowfromtributaries.PercentcontributionfromthesetributarystreamsunderexistingconditionsisshowninFigure7.5.ThemonthlyflowandresultingstageatGoldCreek,SunshineandSusitnaStationwithandwithouttheprojectareshowninFigures9.6to9.8.Underexistingconditionsthelevelofsuspendedsedimentisveryhighinthesummermonths(23to2620ppm)andrelativelylowinthewintermonths(4to228ppm,ADF&G1975).Withtheproject,aglacialflowwillresultyearroundwithsuspendedsolidsinthereleasesatDevilCanyonDamprojectedtobeinthe15-35ppmrange.Changesindissolvedgasses,specificallynitrogen,willbedependentonthespillageoccurrenceandthedesignofthespillways.Althoughitisconsideredthatthemajority ofpotentialnitrogensupersaturationproblemscanbeavoided(orminimized)throughdesignandoperation,sufficientstudyhasyettobeconductedtoconfirmthis.Temperatureofthedischargewaterswillbeadjustedtoapproachthenatur-alriverwatertemperaturesthroughtheincorporationofmultilevelintakestructures.Evenso,slightchangesindischargetemperaturescanbeex-pectedatcertaintimesoftheyear,theextenttobepredictedbymeansofareservoircomputermodelpresentlybeingdeveloped.Althoughitisessentialtoalterseasonalflowsinordertoproduceade-quatepowerduringthewinterwhenthedemandishighest,itispossibletoavoidordampendailyfluctuationsinflowbymeansofoperatingthedown-streampowerhouseasabaseloadplantorincorporatingare-regulationdam.AsthisconstrainthasbeenincorporatedintotheproposedWatana/DevilCanyondevelopment,potentialimpactsassociatedwithdailyfluctua-tionsduetopeakingoperationsareavoided.9-13 (c)MitigatingMeasuresIndevelopingthedetailedprojectdesignarangeofmitigatingmeasure!requiredtominimizetheimpactontheenvironmentwillbeincorporated.Thisisachievedbyinvolvingtheenvironmentalstudiescoordinatoras(memberoftheengineeringdesignteam.Thisprocedureensuresconstantinteractionbetweentheengineersandenvironmentalistsandfacilitatesidentificationanddesignofallnecessarymitigationmeasures.TherearetwobasictypesofmitigationmeasuresthatarebeingdevelopEThosewhichareincorporatedintheprojectdesignandthosewhicharecludedinthereservoiroperatingrules.Thesearebrieflydiscussedbelow.(i)DesignFeaturesThetwomajordesignfeaturescurrentlyincorporatedincludemultlevelpowerintakestructurestoallowsometemperaturecontrolO'releasedwaterandprovisionofadownstreamre-regulationdamtoassistindampingthedownstreamdischargeandwaterlevelfluctu,tionsinducedbypowerpeakingoperationsatthedam.Duringthe1981studiesthesetwofeatureswillbedesignedinmoredetailalotherfeaturesincorporatedasnecessary.Ofparticularimportan'willbethedesignofthespillwaystominimizetheimpactofnitlgensupersaturationinthedownstreamriverreaches.Considerati,willalsobegiventodevelopingmitigationmeasurestolimitthepactontheenvironmentduringtheprojectconstructionperiod.'accessroads,transmissionlines,andconstructionandpermanent,facilitieswillalsobedesignedtoincorporatemitigationmeasur,asrequired.(ii)OperatingRules.AsoutlinedinChapter7,limitationsonseasonalanddailyreserleveldrawdown,aswellasondownstreamminimumflowconditions,havebeenimposed.During1981moredetailedstudieswillbeundtakentorefinethesecurrentconstraintsandtolookatdetailederationalrequirementstoadequatelycontroldownstreamwaterlevfluctuations,watertemperature,andsedimentconcentration.9-14 \1,.1 \1,.1 ~o""'-0 I,-o ~ ""' :.no;:T ......5oroo..I3ro3I-0 ,",':::::10..,M-:::; rD TA8LE 9.1 -OUTFLOWS FROM WATANA/OEVIL CANYON DEVELOPMENT STAGE 1 WATANA 4DO MW Month Average Monthly Inflow (efs) 1Outflow(cfs)Average Average Average Dally Monthly Monthly Peak Offpeak SpIlls (efs) <D I ~ tn JAN FE8 MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Note: 1147 971 889 1103 10406 23093 20344 18012 10614 4394 1962 1385 7699 7409 6758 6168 5689 5571 8227 14263 10299 6503 7497 8237 7834 7538 6873 6264 5699 5571 8ZZ7 14263 10299 6523 7578 8369 7603 7316 6676 6100 5682 5571 8227 14263 10298 6498 7439 8143 1779 6582 2744 (1)Total outflow includes powerhouse flows,compensation flows and spills. " TABLE 9.2 -OUTFLOWS FROM WATANA/OEVIL CANYON DEVELOPMENT STAGE 2 WATANA BOO MW Average OUTFLOW <Cfs)1 Average Monthly Averaga Average Da~ly Monthly Month Inflow (cfs)Monthly Peak Offpeak SpillS (cfs) JAN 1147 7699 15663 2011 FEB 971 7409 14979 2001 MAR B89 6758 13419 2000 APR 1103 616B 12003 2000 MAY 10406 5689 10703 2108 JUN 23093 5571 10524 2033 JUL 20344 8227 11337 6006 134 AUG 18012 14263 15224 13576 431 SEP 10614 10299 12358 8827 OCT 4394 6503 12783 2017 NOV 1962 7497 15139 2039 DEC 1385 8237 16737 2166 <.D I ~ '" Note: (1)Total outflow includes powerhouse flows,compensation flows and spills. 9-17TA8LE9.3-OUTFLOWSFROMWATANA/OEVIL~ANYONDEVELOPMENTSTAGE3OEVILCANYON400MW.Notes:(1)Operatedasabaseloadplant.Minimaldailyfluctuations.(2)Totaloutflowincludespowerhouseflows,compensationflowsandspills.2495871294180AverageMonthlySpills(cfs)866692167394683378068796896716239134917950888993832AveraqeMonthiyOutflow(cfs)85958280757669888235929495241353411188783884629211AverageMonthlyInflow(cfs)MonthJANFE8MARAPRMAYJUNJULAUGSEPOCTNOVOEC ","",·,,"',·....·",·,·,,·~·..~__·'"-'../~".r~...c-."••c-,".....·····w"~c-,,.c-..·~._ins:198419851986198719881989 1990199119921993199419951996YEARI2345678910II12ACCESSTOSITE3PIONEERROAD...CONSTRUCTIONACCESSAtSITEDIVERSIONTUNNELSDEWATERCOFFERDAMSDATIONPREPARAEXCAVATEABUTMENTS7rEXCAVATIONINSIDECOFFERDAMS/FOUNIONI-IFILLPLACEMENT-'IMAINDAM1,2I~ISPILLWAYiNTAKESIPENSTOCKS,POWERHOUSE,,[AILRACEImU,E/GENERATORIITIALIMPOUNDMENTUNITIONLINEWUNIT20NLINEUNIT3ONLINE~~UNIT4DNLlNEANDCOMMISSION""LEGENDNOTESCRITICALACTIVITIES~~'i,~MSCHEDULE;BASEDONFILLPLACEMENTRATESOF2.5m3.0OTHERACTIVITIESCUBICYARDSPERMONTH.SIXMONTHFILLPLACEMENTSEASONASSUMED.KEYACCESSFROMDENALIHIGHWAYANDASSUMESOVERLAND-EARllESTSTARTOFACTIVITYANDAIRCRAFTSUPPORTDURING19B5.IEARLIESTFINISHOFACTIVITYWATANAFILLDAM•I..rLATESTFINISHOFACTIVITYPRELIMINARYCONSTRUCTIONSCHEDULEFIGURE9.19-18 d•.••dd~hC·n;199319941995199619971998199920001992IYUYEARli'lfI23456789ruuIWATAf>lADEVILCANYONROADIMAINACCESSTOSIT,.EIIYUCONSTRUCTIONACCESSATSITEDIVERSIONTUNNELSCOFFERDAMSDEWATERtEXCAVATIONINSIDECOFFERDAMS/EXCAVATEABUTMENTJrFOUNDATIONPREPARATIONIIMAINDAMCONCRETE-,II~AIN2DAMSERVICESPILLWAYEMERGENCYSPILLWAY,INTAKES8PENSTOCKSIo?!'M""l:"DAMrpOWERHOUSEILRACEIURSINEGENERATORUNITIONLINEUNIT2ONLINEITIALIMPOUNDMENTUNIT3ONLINE,UNIT4ONLINE!;TESTANDCOMMISSION,LEGENDNOTES--CRITICALACTIVITIESI.SCHEDULEASSUMESDENALI-WATANAHIGHWAYALREADYAVAILABLE.OTHERACTIVITIESBASEDUPONSIXMONTHCONCRETEPLACEMENTSEASON.2.KEY-EARLlESTSTARTOFACllVITYmIEARLIESTFINISHOFACTIVITYDEVILCANYONTHINARCHDAMI;LATESTFINISHOFACTIVITYPRELIMINARYCONSTRUCTIONSCHEDULE"IFIGURE9.29-19 I...-SPILSIAVERAGEMONTHLYENERGYAVERAGEMONTHLYDISCHARGESTAGE3-WATANARESERVOIR(800MW)OPERATIONOFTHEWATANA/DEVILCANYONDEVELOPMENTPLANE1.3-----,---1--~-----'-----'-,-IIIir'~nrnn~TURBINEnNOTE :WATERYEAROCT.-SEPT,~SECC~DARYf----f\f\1\.~V\.JV\.I\J(\V\~IV\.f\~~(\1(\V\.Jf\(\&~~rir~J(\f\V\IV\f\iI\.f\fF1RMIe-'e-r:e-'r'e-e-tC:",r','e-,e-,,,-'Il,~n-l1~111f1'111j~~r~1Ii~~JlIL-lJl"JUl~rJlJ1ll,.~lllrl11~L'"lr~1r1(1lI~J~J~,kJ~J~Jll-lu~lJ~JU,~J1[~ul!rnjL1-1-Il.,~~ll-L--It-J~J1-..iL-U'-...-J~c:•Co·e-r',e-,,,(.)o'*0"0'enLL(.)Uc:..........C)"3,JCJ....JLLz25,-1•o13",019",119..;219.;319.;419551955,957,95819591960196119621963196419651961319S7i96819591970197j137213731974137519u,1977 19781979AVERAGEMONTHLYINFLOW~~~~rv~~~~~~1r'1,J~~~lr'\JhJlr"'l...J~~IF\,Jl~~frlrr'l,.J~~~~~~.r'1,JIO1950195113521953195419551955,357,95819591950,961196219S3,964196519661967,96819691970,97,19721973,974I:F51971)19771978I:F9uen(,')~oc/).--+----/---+--f---+---j---f---I+--f---+---+---+--II+---I-f-----1i1t---l---+---I----I-f----+----/---+----1f---+---j----/---+----'f---+---t----iLL(')urJo~MAXIMMELEATION~~--l~---I-r~-J+--\-,-!.,-rI\-frl---~--r-I-~\-jrl---\---'+1~-;,.-I,-\-;-,-!t-~-Jrl::--\--,-j,(I\----r(-I::--\--r---b;~\----r~-+-~--r-l:-Jr\-,frl::--\--r+J\-frt--~-r+~~--+---+--+-!l,-rlj~-f-;:rf--~--+/n,-j-,-!,-\--+r~-irl;-~---;:;t-f\--:rlf~~lV\j\fVlJ\J\s\)1J\)VLJ\\r\1J\JVlJV \rh~\)\JV \I\J\.LJV«o--l---+--=tF-+~-----+---+---+-----+---+---+-----+---+---+---+---+----+-----+---+---+--+----+--+--t---::J\!cfl::--\++-----'1+--+ru---+-----+--'Tr-+U---+----+--+-1>GiLLJ'....Jo-+------I------I-----l---I---+----+-----I---~-+__-_I_-_+-___+--.J---+_-_l_-_+-___+--+___-+_-_l_-i.,...JY_-.l.:r..l..--l---+----f----+---+---I,---+----f-----j~~;tMINIMUMELEVAION(.)I!~~....I.-,.-I=95""'·O~I'-';9=5-'-l--!-;-I9=S=2--L..,j"'9=S3"...L-;-;j9=S'"74-!"'-;-j=')S""'S,.--!-.1;-::;9""S7"6-'-.-1""g5=-=;7,..--J-..,1~9=SSr:-,~1,)=5=9---l.-.-1"9=60~-;-::,9"'6-;-1-.1......;-1=96r-;;2;--!-;-;:19;'7'6"'3.-1--,-1=g6"'-;4--L..,1-:::9=65~<:19=6:76""':'-'1=96r.-::7,.-l-;-;:j9""6;=:-8--'-<-1M96::-;';9;-!-;1;C;9:7'7O;:::-'--:-:j9:vi7"j.--!.....;-1§72 1j73 , 9741975 1971)i977197S1979AVERAGEMONTHLYELEVATION'*(.)C) AVERAGEMONTHLYDISCHARGEFIGURE9.5[j]1977197819791976197~)19741973i*--SPILLS19571958195919601961196219631964196~1966196719681969197019711972AVERAGEMONTHLYELEVATIONSTAGE3 -DEVILCANYONRESERVOIR(400MW)OPERATIONOFTHEWATANA/DEVILCANYONDEVELOPMENTPLANE1.3NOTE:WATERYEAROCT.-SEPT.19511')5219531954195519561950~MAXIr-.UMELVATIOf\Il!trvtlNIMUMELEVAION..,'c-...,c-,--,s~JrfJ..-,rrIrrrnf"nr'lnnI~LJ-JIn,JU~~J~r"JUr~nJJ'~lJJ'1.JllLJ..J\rt:~CJ~-'~J..J'Y~s\JV"\l.r~-r'VrvUpV~i~~~f"tJlJ'L~\J~l\Jlrcp/(J"l.t~,,-n'w-If"'lJ~J'~J"\rJL"..._'"<.,.,,J--'~~".,._."r•(\r'i\""'(:('C:-.'"\,..;.r'1:f:,r..-,,;..~-c-,--;,,.,,n(j)LL00...........(')W.-;-----j---+------ir----t---f----li---lIIII-----I---It-----;i------it---I+---,---~-~IIII.II.rTJRBINElliG°~~~Lr'-'""'"'l.J'UIt'"'-'1Jl.f1J""-'1...,.f.r'"'-'1.,j~•~V"lJ....~~~~V"';Ii"1..J~""'It:V';;:;"'4,.r';-;:;:f"Iu-rb=""l;:;:;VIIrt:lt.ll.r't.r:;;:;"'"'V'"~f"br"1J;::;:;--JrJ'ltfJ":;:;:·~;;t----t?,T'O'j.uiITr1lr--::i:frr-dt·V-"bV'"'l;V'lJJTi/.)-n~-;:;;:;;--=-t.:~;;:;;-::-j.r"7""lLi1'V-:::rr:-.....~'l.rL.,.-:::;-t?fJ""'"'G'jV-;:lflfijUV;:r;:~;;-----t?~;::;::;--r1~~~J-:I-.:9-;:5-;:-0-'--,1-.:9-;:5-:-1-L1-':9C;=5=2-L1'"""'9"'5""3.....L-'"""'19"'~"""'4-'--,1""''J'"'''5=5---l-'''''19'""'5=6-'-:-<:19""'5=7-"--:-:19""'5"""8---'-7""19~5"""9,-J-7""19"""'6~0,-J--'-19"""'6::-:j--L-:-1-;:-96;:-;~""'"-'--:--1"'9S=3.-L--;-1""-95-;:-4.,.--!..--;-1""-9=65;=-!---;-1=9'A66;:--!---;-1=9'A67,.-L-'1"""9'A68~-'1~9""-6A'-9J-,1~9-=77'AO--'---;1-':9-;;'7-;-1-1.....;1-':9=7"'2---'-:1:-::9""7-=73-'--:1;-;:9'""'7-;"4-'-1"'9;-=;7=5-"-1"'9;-=;7""6-'-"19;-=;7""7.......L"19'"7~8~;-;19'"7"'9:-'O·L.iJ.-J0We;'oi.{)(\J()oAVERAGEMONTHLYINFLOWtv)o-0ilf0-l---I--+---ji----+---!----+---l----j----f---+--+---+--+---+---1----+---1----t+--+---t-----I---j---I---I---+-----1I---+--I---+-----$)o1'030DO___J.-LLZ.--<()o>-og~c;-1'1"9:<"5"0-'--,1"9~5'1-L.;1-;=9;c5-;:;2--'-;1;-;:9;c573~1;-;:9;;=5"4-'--,1;-;:9;;=575---l-1"9;;=57-6-'-"19"'5'""7-"-"19"'5"'8:-'-"19"'5'7-9;-'-<;19::;;6"'0;-'-<;19"'6"'1--L'19"'6::-;-2\'-'1A:g6~3,-'-'1A:96c.-:-4'-:'-'1"96""5",--1-'17-'95""6;:-'--'-;-17-'96T-'?~<j"9;<";68,,-'-'1"97:69;;;-L'1"9770~-;-1r:9777'"1...1.-.1"9-=77"2-"-'1"9':=77"'3-'-;1"9~7A4-'-;1-;=9>77-pS-e,1;-;:9>7771)---'--,1;-;:9>7777--'--,1;-;:9>77'78-'-1"9"'7'C\9-J~AVERAGEMONTHLYENERGY('$00--0if.>C)()(\J 1312....l1Jl1JlL.I....IG:I:C!)l1J:I:15l1JC!)<X:C!)14FIGURE9.JiiJ25501059-23RETURNPERIOD,YEARS2DISCHARGE-STAGEFREQUENCYCURVESUSITNARIVERATGOLDCREEKRIll-~-II•!"POSTPROJECTI"~•~(BESTEST!M~TE).-----~...c:---'---POSTPROJECTI,(LOWERLIMITI,~+-;---,-t,It,,I,-++iII':,II IIII!I!I'II1III".,I!!II~+I,IIII,III!i!I,II\ II2545244101059876OTE:BASEDONPRELIMINARYDATA,SUBJECTTOREVISION FIGUREJ11mICURVESTATION9-2425102550RETURNPERIOD)YEARSDISCHARGE-INOTE:BASEDONPRELIMARYDATAISUBJECTTOREVISION610987654323222120219(/)18lJ..U171-I16~l.LJlJ..(!)15Ia::«l-I514IU10(!)(/)13wCi9I~8l.LJ:;:)(!)~7«X(!)«6~543 FIGURE9.81111I25102550RETURNPERIOD,YEARS9-25DISCHARGE-SUOTE:BASEDONPRELIMINARYDATASUBJECTTORETURN261l-I~LLJ~U.a::59~~:t::t:~Icr~eBLijis9:t::IE8:rLLJ::;:)~:IE7~X~6 omDEC.1981DEVILCANYONSCHEMEIPLANANDSECTIONSU$ITNAHYDROELECTRICPROJECTEL.14~4'FUSEPLUGso'PLATE10~------------jALASKAPOWERAl,JTHORITYCUT-OFFTRENCHSE.CTIONA-AMAX.NORMALOPERATINGLEVELEL.'450'!/!8ttl140010001500,------1----.---.--LOCALlZE.DCONCRETELINING;'"DATEARRANGEMl:.NTGENEQA.L'-ALLUVIUMS>lOULD&.DREDGE.DOUT7\~l)I---------_.\"1\\\\\ IAVG.TWLEL.8':>0'.,nDEC.1981DEVILCANYONSCHEMEISECTIONSI.pomjl--_ALA_SKA----:::-::PO:-:-:W::-::-E:-;:R-::A:-:-:U:-;-T-;;-HO;;-;;R:-;-;;IT:;:-;Y;-1MUldSUSITNAHYDROELECTRICPROJECTPLATEIIDIVERSIONTUNNELSSUIZFAce(12K?,~T~IDE)REVISIONSPROFILE(L.ooKINGUPSTREAlyl)DAM"-"-"-""SeAl-Eo0100200FEET~I~~_-!,,SOUNDeEDROCKSURFACE-UPSTREAMI·/''00UNDBE.DR.O~SURFACE-DOWt-!STREAM/ /5ECTIONTl-lRUSPILLWAYFIXEDw~EiJ..<SATE.S800L-==A"""'LU....,VIUMDlZED4elOOUT~700-L-----------------------------------------------8001---------------.---------------'.3;::;=:::t=-~-_d::k;'------------'100flOCK(T'(R)1100L---,_11001'1.001----------------I~OOl-·-----~;;::---~-~:::_----------------------r=:E~Ll:."Ti4lD4lD:z;:z;1..'----------------:----.................~-',1400~---:-:~:-:-:=-===::;--~~~--~P''-<:-----------------------==---------~7'i----1-----AU~ILIAIl!""SPILLWAY--i1iI~~1000l·--------------------·-----------~~~,--------7i!_j------------------~-,,-'_.......NATURALSURFACe.-(LEFTSIDE)SECTIONTHRUPOWERFACILITiESGROUTCURTAINMIN.RWLELIz,oo'EL.I'lGS'MAX.NORMALOPERATING_LEVELEL.1460'::<t-:J!-----j1!1<=11=12001=CROWNSE.CTIONMAX.NORMAL.OPERATINGlEL'LEVELEL.14S0'~.14&..lCONCRE.TEPL.UG1100'\._NAiURALSURFACE',,,~(RIGI-liSIDE)12=~------------__IHi_-~~~---t:L---------O"''''0,~------,"-,'''-......1500130014=1----------------'-',,-\''''.1=~-----------------------------~~~:---j'-=-_:=-7-~~------:.,'\""--"-~\------AVG.TWLEL.890'qOO~----_\E~~~=: WATANASCHEME2~..DEC.1981~.----~,."~ZoO°r\950~/"\900/\1350~--12ALASKAPOWERAUTHORITYSU$ITNAHYDROELECTRICPROJECTo2004JX)fE.E.T'8.:ALE:~i~~§__~PLATECH.'AIL.RAcE:TUNNEL.40'CIA.GENERALARRANGEMENT WATANASCHEME2SECTIONSomDEC.19SIALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTr~I~I~l04.An.SCALE:BREVISIONSSECTIONC-CSCALE:A------,-----100'DATE'2200['2ISO....,.~"""'-_j_-----_j_+¥"'''''''-----------SCALE'.A 050100FEE.T2100-----fj~~~~===tr----S;;:;:E5~i~~§iiiiiiiiii~!SCALE'.I:>0 510FEETiIPLATE13I---¥~-----------------+-t-t--t~fiSECTIONE-ESCALE.'ABEDROCK.SUl2FAOE---1800I&SOSCAl.E.'ASECTIONB-B2.100SCALE.:A22001------~W--l__I--+__+__--1-.l,-----DRAINAGE.GALLE.RYSECTION0-0'2250-------...j21SO1900---ORIGINALGROUND-..........-__-------------N.RWL.EL.'2.'2.00I---SCALE'A3-W"'E"~LMOUNTEDGATES-351W)(40'l4----15S0r-----------------------------"m~~~~~"'E~~"::::~::_---'<:000EXCAVATEALLUVIUM1500I-~~:::",.._===__-.:......,.....::~__==-__--,'~INRiVERBED17501800_.--..--2'200f..----------.f-}H-,l-.Jo<->.....-.I--t<>.....-.I'H----..l...L'--'..-'-!....L..L.L------=-""''''-------I(OSO+----------------2;>oO,----J.."--"--':B=--_-.jj...r'-Il---------___,ORIGINALGROUND...------___,.SURFACE.-RIG14TSIDE.'2250I--------------Ih+-----:-::-~-=_=_=__--O"""~=----~'------;:;;25'--~------,--.............-a-WHE.E.L.MOUNTE.O----:::------_~..rre.'5-=OIW.xA011-t.---"'---"_.19CD'22001--.....~!;;!!!!!!""'"----;;7-L-=---+t--::-::::-:-~1--~----~~:O,::~~±~=~~~~~=:;::::::;;;~~O~R~'~GIN~A;L~G~R:0;U~N~D~~-~-~--~~-~--~9~-~-;~~-~----~~-=-==~~~;;~=~:~:c=:~~Zl~s--sURFACE.-LE.FTSIDE.SOUND=1<:----_____2150---l2IG14TSIDE------_-----..,-"-..-..LFt"-"-"-"-"-..2100f::'E'Lc,'2'I"'S:':::'.,I"'"""':===~~f;~----~E.::::::========,...,."';r~:.:.-::~..:=.=.~~..;;~.·~·~;~·~·_;;;··;;;~..~~..~~:..::::~~~;=~~~~~~::2"':':'::::~':":::=:===:::~~--/I!----------"0II-,-------.....I~,-,,Z0501-------GROUTCURTAIN--1-rlll-----------------------------------------------------::::::::::;;;;;,~g:::::o~~.....;;:_--------..::.:::::,,-....:;c:::_---=:::::::=..~===_--------'Ai,IIB•-.C~-,'-.------~'"~-~iIIPRESSURERELIEFSPlLLWAYPROFILE"_1,//DRAINs-'_____..,"_,~.SCALE.: 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10-CONCLUSIONSANDRECOMMENDATIONS10.1-Conclusions(a)AstandardmethodologyhasbeenadoptedtoguidetheSusitnaBasindevelop-mentselectionprocessdescribedinthisreport.Itincorporatesaseriesofscreeningstepsandconcludeswithplanformulationandevaluationpro-cedures.Boththescreeningandplanevaluationproceduresincorporatecriteriarelatingtotechnicalfeasibility,environmentalandsocioeconomicaspects,andeconomicviability.(b)TheeconomicanalysesarerequiredtoassisttheStateinallocatingfundsoptimallyandarethereforeconductedusingareal(i.e.inflationadjust-ed)interestrateof3percentandacorrespondinggeneralinflationrateofzeropercent.Fuelcostsareassumedtoescalateatspecifiedamountsabovethegeneralinflationrate.(c)Previousstudiesoverthepast30yearshavethoroughlyinvestigatedthepotentialofthebasinandthemostrecentstudiesconductedbytheCOEhaveconcludedthattheWatana-DevilCanyondevelopmentplanistheprefer-redoption.However,reviewofthesestudieshasindicatedthatacertainamountofrevisionisappropriate,bothtodevelopamoreuniformlevelofdetailforallthealternativesitesconsideredandtoreassesstheearlierplanningdecisionsinthelightofcurrentloadprojectionswhicharegenerallylowerthanthoseusedintheearlierstudies.(d)Thecurrent(1980)RailbeltSystemannualenergyrequirementisestimatedtobe2790Gwhandthepeakdemand515MW.Nearfuturedemandscanbesat-isfiedbytheexistinggeneratingsystemplusthecommittedexpansionatBradleyLake(hydroelectric)andthecombinedcycle(gasfired)plantatAnchoragetill1993providedanAnchorage-Fairbanksintertieofadequatecapacityisconstructed.(e).Energyandcapacityforecastsfortheyear2010canbesummarizedasinTable10.1.(f)Arangeoftechnicallyfeasibleoptionscapableofmeetingfutureenergyandcapacitydemandshavebeenidentifiedandincludethefollowing:-Therma1Units•Coalfiredsteamgeneration:100,250,and500MW•Combinedcyclegeneration:250MW•Gasturbinegeneration:75MW•Dieselgeneration:10MW-HydroelectricOptions•AlternativedevelopmentplansfortheSusitnaBasincapableofprovid-ingupto1200to1400MWcapacityandanaverageenergyyieldofapproximately6000Gwh.10-1 TenadditionalpotentialhydroelectricdevelopmentslocatedoutsidetheSusitnaBasinandrangingfrom8to480MWincapacityand33to1925Gwhannualenergyyield.(g)IndicationsarethattheutilitieswillbesubjecttotheprohibitionsoftheFuelUseActandthattheuseofnaturalgasinnewfacilitieswillberestrictedtopeakloadapplicationonly.(h)TheSusitnaBasindevelopmentselectionstudiesindicatedthatthe1200MWWatana-DevilCanyondamschemeistheoptimumbasindevelopmentplanfromaneconomic,environmental,andsocialpointofview.Itinvolvesa880feethighfilldamatWatanawithanultimateinstalledcapacityof800MWanda675feethighconcretearchdamatDevilCanyonwitha400MWpower-house,anddevelopsapproximately91percentofthetotalbasinpotential.'"Shouldonlyonedamsitebedevelopedinthebasin,thentheHighDevilCanyondamwhichdevelops53percentofthebasinpotentialprovidesthemosteconomicalenergy.Thisproject,however,isnotcompatiblewiththeWatana-DevilCanyondevelopmentplanasthesitewouldbeinundatedbytheDevilCanyondevelopment.(i)ComparisonoftheRailbeltsystemgenerationscenarioincorporatingtheWatana-DevilCanyonSusitnadevelopmentandtheallthermaloptionrevealsthatthescenario"withSusitna"iseconomicallysuperiorandreducesthetotalsystempresentworthcostby$2280million.Anoverallevaluationofthesetwoscenariosbasedoneconomic,environmental,andsocialcriteriaindicatesthatthe"withSusitna"scenarioisthepreferredoption.The"withSusitna"scenarioremainsthemosteconomicforawiderangeloadforecastandparameterssuchasinterestrate,fuelcostsandfuelescala-tionrates.Forrealinterestratesabove8percentorfuelescalationratesbelowzero,theallthermalgeneratingscenariobecomesmoreeconom-ic.However,itisnotlikelythatsuchhighinterestratesorlowfuelescalationrateswouldprevailduringtheforeseeablefuture.(j)Economiccomparisonsofthegeneratingscenarios"withSusitna"andthescenarioincorporatingalternativehydrooptionsindicatethatthepresentworthcostofthe"withSusitna"scenariois$1190millionless.(k)PreliminaryengineeringstudiesindicatethatthepreferreddamtypeatWatanaisarockfillalternativewhileadoublecurvaturethinarchcon-cretedamisthemostappropriatetypefortheDevilCanyonsite.10.2-RecommendationsTherecommendationsoutlined inthissectionpertaintothecontinuingstudiesunderTask6DesignDevelopment.Itisassumedthatthenecessaryhydrologic,seismic,geotechnical,environmental,andtranmissionsystemstudieswillalsocontinuetoprovidethenecessarysupportdataforcompletionoftheFeasibilityReport.ProjectplanningandengineeringstudiesshouldcontinueontheselectedSusitnaBasinWatana-DevilCanyondevelopmentplan.Thesestudiesshouldencompassthefollowing:10-2 (a)ProjectPlanningAdditionaloptimizationstudiesshouldbeconductedtodefineinmoredetail,theWatana-Devi1Canyondevelopmentplan.Thesestudiesshouldbeaimedatrefining:-Damheights-Installedcapacities:aspartofthistaskconsiderationshouldalsobegiventolocatingthetailraceoftheDevilCanyonpowerhouseclosertoPortageCreekinordertomakeuseoftheadditionalheadestimatedtoamountto55feet.-Reservoiroperatingrulecurves-Projectschedulingandstagingconcepts:amoredetailedanalysisofthestagingconceptshouldbeundertaken.Thisshouldincludeare-evaluationofthepowerhousestagesizesandtheconstructionschedules.Inaddition,anassessmentshouldbemadeofthetechnical,environmentalandeconomicfeasibilityofbringingtheDevilCanyondamandpowerhouseonlinebeforetheWantanadevelopment.ThismaybeanattractivealternativefromaschedulingpointofviewasitallowsSusitnapowertobebroughtonlineatanearlierdateduetotheshorterconstructionperiodassociatedwiththeDevilCanyondam.ThegeneralprocedureestablishedduringthisstudyforsiteselectionandplanformulationasoutlinedinAppendixAshouldbeadheredtoinunder-takingtheaboveoptimizationstudies.(b)ProjectEngineeringStudiesTheengineeringstudiesoutlined inSubtasks6.07through6.31shouldcon-tinueasoriginallyplannedinordertofinalizetheprojectgeneralarrangementsanddetails,andtofirmuptechnicalfeasibilityofthepro-poseddevelopment.(c)GenerationPlanningAsoutlined intheoriginalTask6.37studyeffort,thegenerationscenarioplanningstudiesshouldberefinedoncethemoredefinitiveprojectdataisobtainedfromthestudiesoutlined inSections(a)and(b)aboveandtheRailbeltgenerationalternativesstudyiscompleted.Theobjectiveofthesestudiesshouldbetorefinetheassessmentoftheeconomic,environ-mental,andsocialfeasibilityoftheproposedSusitnaBasindevelopment.10-3 TABLE10.1-ENERGYANDCAPACITYFORECASTSFOR2010ProjectAnnualEnergyDemandEquivalentPeakAnnualRateDemandLoadGrowthGwhofIncreaseMWVerylow(Le.incorporatingadditionalloadmanagementandconservationmeasures)5,2002.1~.920Low6,2202.7%1,140Medium8,9404.O~.1,635High15,9306.rl'.2,90010-4