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Home My WebLink AboutKing cove Oldharbor Larsenbay Hydro project Vol A Final Summary Report 8-1982Volume A FINAL SUMMARY REPORT Feasibility Studies for KING COVE HYDROELECTRIC PROJECT OLD HARBOR HYDROELECTRIC PROJECT LARSEN BAY HYDROELECTRIC PROJECT Reconnaissance Study for TOGIAK HYDROELECTRIC PROJECT Submitted by DOWL ENGINEERS ANCHORAGE, ALASKA In Association with TUDOR ENGINEERING COMPANY SAN FRANCISCO, CALIFORNIA DRYDEN & LARUE ANCHORAGE, ALASKA AUGUST 1982 e• ALASKA POWER AUTHORITY Volume A FINAL SUMMARY REPORT Feasibility Studies for KING COVE HYDROELECTRIC PROJECT OLD HARBOR HYDROELECTRIC PROJECT LARSEN BAY HYDROELECTRIC PROJECT Reconnaissance Study for TOGIAK HYDROELECTRIC PROJECT Submitted by DOWL ENGINEERS ANCHORAGE, ALASKA In Association with TUDOR ENGINEERING COMPANY SAN FRANCISCO, CALIFORNIA DRYDEN & LARUE ANCHORAGE, ALASKA AUGUST 1982 ALASKA POWER AUTHORITY SUMMARY VOLUME CONTENTS Section Page FOREWORD I. INTRODUCTION I-1 II. KING COVE SUMMARY II-1 III. OLD HARBOR SUMMARY III-1 IV. LARSEN BAY SUMMARY IV-1 V. TOGIAK SUMMARY V-1 NBI-432-9526-SC i FOREWORD This volume, Volume A, is a summary report incorporating the findings, conclusions, and recommendations of the feasibil- ity studies for King Cove (Volume B), Old Harbor (Volume C), and Larsen Bay (Volume D) and the reconnaissance study for Togiak (Volume E). Volumes B through E are comprehensive individual project reports that present the findings and recom- mendations of studies to assess the economic, technical, environmental, and social feasibilities of hydroelectric projects for these four villages. Each of the volumes for the individual project reports consists of 12 sections and six appendices. The first section of each report is a concise summary of all activities conducted for the particular project. Following a brief introduction, Section I, these summaries from each volume are reproduced here as Sections II, III, IV and V and some similarity in format and narrataive will be noted. Selected photographs, figures and drawings have also been included with each summary section as appropriate. NBI-432-9526-SF ii TOGIA KING COV Ci 0 oQ oD LARSEN BAY LOCATION MAP FIGURE 1-1 SECTION I INTRODUCTION A. GENERAL This summary report presents the overall results of studies conducted to appraise proposed hydroelectric projects at King Cove, Larsen Bay, Old Harbor and Togiak. With the exception of Togiak, all studies were at the feasibility level and included the optimal sizing of all project features. The studies for Togiak were at a reconnaissance level since the prior studies were not as extensive and since the proposed project involves a small dam and is more complex. The studies were authorized by the Alaska Power Authority as a result of numerous prior studies of energy alternatives that had recommended hydroelectric projects as the best source of future electric energy for the four villages. In addition to the hydropower alternative, the continued use of diesel generators, the installation of waste heat recovery equipment, and the installation of wind powered generators were all considered as possible future energy sources. The overall results of these studies indicate that feasible hydroelectric projects can be constructed at King Cove, Old Harbor and Larsen Bay. The study for Togiak indicates that a hydroelectric project of sufficient size to satisfy the overall electric demands is marginal at best and then only if 7.0 miles of the required 11.6-mile access road to the site is con- structed by the Alaska Department of Transportation. It may, however, be possible to construct a much smaller hydropower site near Togiak which would satisfy at least a portion of the electrical needs of the village. This site is currently being assessed at a preliminary level and will be addressed in a later report. NBI-432-9526-SI I-1 Any or all projects studied could be constructed and on- line by January 1985 if a decision to proceed is made by December 1982. B. PURPOSE AND SCOPE OF STUDIES The primary purposes of the studies for King Cove, Larsen Bay and Old Harbor were to prepare recommendations of the best configurations for developing dependable sources of hydro- electric energy supplies for the villages and to determine the engineering, environmental, and economic feasibilities of the projects. For Togiak the primary purpose was to determine if any feasible project could be constructed with the intent to optimize the project features in the next phase if overall feasibility was demonstrated. The general scope of the studies consisted of first projecting the future electrical energy needs of the villages over a 20-year planning period and developing alternative diesel and hydroelectric project scenarios to meet those projections. Increases in demand for energy and the cost of petroleum products were recognized for a 20-year planning period extending from 1982 through 2001. The demands and costs were assumed to be constant after the 20-year planning period. The period for economic evaluation extended 50 years past the on-line date for the hydroelectric alternative. Economic comparisons were then made between these alternatives, the environmental effects were assessed, and conclusions and recommendations were formulated. NBI-432-9526-SI I-2 The diesel alternative for each village was know❑ as the "base case" plan and was essentially a continuation of the present diesel generating plants, enlarged as necessary to accommodate future growth. Heat recovery, to be used for local space heating, was incorporated with the base case plans to the maximum extent that is economically feasible. Wind generation was also considered as part of the base case plan and was found to be economically feasible, although of limited value, at all four sites. Some hydroelectric energy was also used for space heating. I❑ assessing power and energy priorities for the hydroelectric energy for each village, the first priority was given to the direct electrical demand for the village. The second priority, when excess energy was available, was the cannery demand (King Cove only) and the third priority was the village space heating demand. C. OVERALL STUDY RESULTS A table presenting the size, average annual energy generated, the estimated cost (in 1982 dollars), the fuel oil displaced by the hydroelectric energy, and the benefit/cost ratio (B/C) for each project is presented below. The B/C ratios shown reflect the benefits from waste heat recovery, and wind generation and the utilization of excess electrical energy for space heating (and the cannery at King Cove). A more detailed summary is contained in the following sections of this volume: King Cove, Section II; Old Harbor, Sect -ion III; Larsen Bay, Section IV; and Togiak, Section V. NBI-432-9526-SI I-3 Average Annual 1982 Fuel Oil Project Size Energy Cost Displaced/Yr. B/C (kW) ^\J kWh $ (Gal. ) King Cove 575 \ _.2,280,0001. 3,744,90010Yr143,700 2.011 054 Larsen Bay 270 " , 1, 090, 00e, 2, 8;1, 400 °ii0Ap 85,700 1.237 yd Old Harbor 340 0�'L--1,310,000,4`11=3,082,300 �; N' 1039300 1.403 Togiak 432 6iV 2,660,00041119 7,047,200 189,800 1.024 (lid 'CA. i C..'•. 5� 92n°fin The values given above for fuel oil displacement are for a combination of diesel fuel used for diesel generators and space heating. As the B/C values in the above table indicate, the projects for King Cove, Larsen Bay, and Old Harbor are feasible. The Togiak project is marginal. As is presented in the following more detailed summaries for each project, it is possible to derive several different B/C ratios for each of the projects. This is because the calculated B/C ratio for a given project depends on which combination of assumptions concerning waste heat recovery (from the diesel generator), space heating (from the hydroelectric energy in excess of the villages electrical demands) and supplemental wind generators are utilized. For example, the B/C ratios presented above are somewhat lower when the benefit of space heating with excess hydroelectric energy is not included. D. STUDY PARTICIPANTS DOWL Engineers, of Anchorage, Alaska, was the primary con- tractor for the study. DOWL was assisted by two subcontractors- -Tudor Engineering Company of San Francisco, California, and Dryden & LaRue of Anchorage, Alaska. DOWL performed the project management functions and provided all geological, geotechnical, NBI-432-9526-SI I-4 and environmental information. Tudor, as principal subcontrac- tor, supplied all hydroelectric expertise for the project and compiled the project report. Dryden and LaRue formulated the demand projections and supplied all diesel generating and transmission line information. E. ACKNOWLEDGEMENTS The cooperation of the many federal, state, and local agencies and local residents contacted during the course of the study is gratefully acknowledged. This list includes, but is not limited to, the Alaska Power Administration, the Alaska Department of Fish and Game, the Alaska Department of Trans- portation, the U.S. Army Corps of Engineers, the U.S. Geologi- cal Survey, and the U.S. Fish and Wildlife Service. The assis- tance of the Rockford Corporation and the Locher Construction Company, a subsidiary of Anglo Energy Company, is also acknow- ledged. We especially wish to thank the Alaska Power Authority and their program manager for the project, Mr. Don Baxter. NBI-432-9526-SI I-5 SECTION II KING COVE SUMMARY INTRODUCTORY NOTE: Presented in this section is the Summary from Volume B-- Feasibility Study for King Cove Hydroelectric Project. Included for general background information are several items from that report: Exhibit VI-1, Photographs of the Project Area; Figure VII-39 Projected Monthly Generation, Demand, and Usage; and selected project drawings which include Plate I, the General Plan, Plate III, the Penstock Plan, Profile and Details, and Plate VI, the Powerhouse Plans and Sections. References to figures, exhibits, and plates in the summary presented here refer to items in Volume B, the full feasibility report for the King Cove Hydroelectric Project. NBI-432-9526-SKC II-1 KING COVE SUMMARY A. GENERAL Several prior studies of alternative means of supplying King Cove with electrical energy had recommended a hydro- electric project as the best source. As a direct result of these prior studies and recommendations, the Alaska Power Authority authorized a feasibility study to investigate in detail the hydropower potential in the vicinity of King Cove. This report summarizes the activities conducted for the feasibility study. These activities included projections of energy needs, formulation of a hydroelectric project plan and an alternative base case plan to meet the electrical energy needs of King Cove, detailed analyses of economic feasibility of each option, and preparation of an environmental assessment of the effects of the project. The results of the study indicate that a 575 kilowatt (kW) hydroelectric project can be constructed at King Cove, that the project is considerably more economical than the base case alternative, and that the environmental effects of the project are minor. The estimated total construction cost of the proposed King Cove hydroelectric project is $3,743,900 i❑ January 1982 dollars. The project could be implemented and on-line by January 1, 1985, if a decision to proceed with the project is made by December 1982. During an average water year, the proposed project would be capable of supplying more than 90 percent of the electrical needs and some of the space heating needs in the project area. The equivalent savings in diesel fuel in the year 2001 would be about 120,000 gallons for direct electrical demand and 23,000 gallons for space heating. NBI-432-9526-SKC II-2 B. AREA DESCRIPTION King Cove is located on the western end of the Alaskan Peninsula near the beginning of the Aleutian Island chain. With the exception of Cold Bay/Fort Randall 18 miles to the northwest, the nearest major towns are Dillingham, King Salmon, and Kodiak, 300 to 400 miles to the northeast. The selected hydropower site is located on Delta Creek about five miles north of town. The project area and the proposed site are shown on Plate I of Appendix A. C. POWER PLANNING Power planning for the King Cove Project was conducted using standards set forth by the Alaska Power Authority. Previously recommended potential hydroelectric sites were investigated and the project area was surveyed to evaluate potential new sites. After detailed study, a project was selected and then compared with a base case plan. The base case plan consisted of a continuation of the present diesel generation system, enlarged as necessary to meet future growth. The base case also included the installation of waste heat recovery and wind generation. These were both found to be viable for installation. Present energy demands for King Cove for direct electrical uses, cannery use, and space heating were estimated and future uses in these same categories were projected. The projections were based on forecasts of increases in the number of customers and increased usage rates. Population growth and employment, legislation and other political influences, life style changes, and other factors can influence future energy demands but they were not explicitly treated. NBI-432-9526-SKC II-3 The period of economic evaluation used was 53 years, which starts in January 1982 and extends for the 50-year life of the hydroelectric project after the estimated on-line date of January 1985. The energy demands for King Cove were increased for 20 years starting i❑ January 1982 and extending through December 2001. The demands were then held level over the remainder of the economic evaluation period. The cannery demand was assumed to remain constant over the entire period. For the proposed hydroelectric project, it was assumed that the first priority of use for the energy produced would be the direct electrical needs of King Cove, second priority would be for the cannery requirements, and remaining energy would be used for space heating to as great an extent as possible. D. DESCRIPTION OF RECOMMENDED HYDROELECTRIC PROJECT Hydroelectric power plants transform the energy of falling water into electrical energy. Generally, a hydroelectric power project consists of a dam to produce the head or to divert stream flows so that they can be passed through a turbine - generator system to produce electric power. In the case of the recommended King Cove Hydroelectric Project, a low weir will act as a dam to divert water from Delta Creek through an inlet structure and into a penstock (conveyance pipe). The penstock will be 36 inches in diameter and it will carry the water about 5300 feet to the powerhouse, where it will be passed through the turbine -generator system to produce electric energy. The project will incorporate a sediment basin near the diversion weir to trap and remove sediment from, the water before it enters the penstock; otherwise, coarse sediment might damage the turbine. The powerhouse will have the capacity to produce 595 kw of electrical power. A transmission line will be constructed to transmit the power generated at the plant to King Cove. Access NBI-432-9526-SKC II-4 to the powerhouse facilities will be provided by building a new road to link up with the existing road at the King Cove Airport. The transmission line will follow the alignment of the new access road and the existing road from the airport to King Cove. The general plan and features of the proposed project are presented on Plates I through VIII of Appendix A. Photographs of the project area are presented in Exhibits VI-1 and VI-2 at the end of Section VI and in the Environmental Report, Appendix E. Under the recommended plan, energy generated by the hydro- electric plant will have to be supplemented by diesel genera- tion. The entire existing diesel capacity will be required as standby and backup power. The hydroelectric generation will be adequate to meet the direct electrical needs of King Cove (not including the cannery) during most of the year; however, from December through March diesel will be necessary to supplement the hydrogeneration. Diesel will also be needed at times to meet the needs of the cannery located in King Cove. In all, during an average water year the proposed hydro- electric project will be capable of supplying more than 90 percent of the electrical needs of King Cove and approximately one-third of the cannery needs. Average annual energy production from the hydroelectric plant will be 2.28 million kilowatt-hours (kWh) and the average annual plant factor will be about 45 percent, which means that the plant is expected to generate about 45 percent of the energy that it could produce if the turbine -generator unit was operated continuously at full capacity. E. BASE CASE PLAN The base case plan formulated to meet the projected energy demands of King Cove assumed that the existing diesel system NBI-432-9526-SKC II-5 u would continue to be used as the sole source of electric power, excluding the cannery. Because of apparent economic benefits, it was assumed that the system would incorporate waste beat recovery that would be used for space heating. The installation of wind generation equipment was also considered and was found to be economically viable. The existing diesel plant's capacity was judged to be adequate to meet peak demands on the King Cove system throughout the period of study. The diesel system at King Cove now uses about 70,000 gal- lons of fuel oil per year; this rate was expected to increase over the next 20 years to more than 128,000 gallons per year. Waste heat recovery was expected to displace the use of 17,000 gallons of fuel oil per year by the year 2001. F. ECONOMIC ANALYSIS The economic analysis was based on the Alaska Power Authority criteria that compare the net present worth of the base case costs to the net present worth of the proposed hydro- electric project costs using specified real price escalation and discount rates. Net present worth is the present value of the costs that would be incurred over a comparable economic evaluation period of 53 years for both the base case and the hydroelectric project. The net present worth of the total cost of the base case plan is $9,287,000. This net present worth is $8,790,000 after adjustment for waste heat recovery; $8,170,800 after adjustment for wind energy; and $12,983,900 after adjustment for the can- . nery credit. In order to compare all alternatives to the hydroelectric project, all costs other than the cost of the hydroelectric project and its diesel supplement were applied as adjustments to the base case. The net present worth of the base case, after all adjustments, including the space heating credit associated with the hydro project, is $14,203,900. NBI-432-9526-SKC II-6 For the proposed hydroelectric project, the present worth of the costs is $7,053,100. A comparison of these net present costs with the base case net present costs indicates that the recommended hydroelectric project is considerably more economical than the alternative base case. An additional measure of project feasibility is the bene- fit/cost (B/C) ratio. The B/C ratio is the present worth of the project benefits divided by the net present worth of the project costs. For this project the calculated B/C ratio is 1.317 when the hydro project is compared to the base case only, 1.246 when the base case is adjusted for waste heat recovery, 1.158 when the wind energy credit is also considered, 1.841 when the cannery credit is added, and 2.011 when all adjust- ments have been made. The annual unit costs of energy production for the base case and recommended hydroelectric alternatives were calculated for each year of the economic analysis in order to determine the optimum timing for development of the hydroelectric proj- ect. This analysis indicates that the hydroelectric project is viable for immediate development. G. ENVIRONMENTAL AND SOCIAL EFFECTS The environmental study results indicate that the effects of the project will be minor due to the limited scope of the project activities, the lack of major fish or wildlife resources in the immediate area, and the availability of measures to mitigate potential effects from the construction and operation of the facilities. Minor socioeconomic benefits will occur as a result of project construction and maintenance and cheaper electric rates made possible by the project. Additional environmental studies do not appear to be warranted NBI-432-9526-SKC II-7 unless regulatory agencies or local residents express addi- tional concerns. H. CONCLUSIONS AND RECOMMENDATIONS The studies conducted for this report indicate that the proposed 575 kW project is feasible and that the energy demands of King Cove are sufficient to utilize the hydroelectric plant's planned capacity. The proposed project is a more economic means of meeting the area's future electric needs than the base case diesel alternative. Environmental effects of the proposed project are minor. In view of these findings, it is recommended that actions be initiated to implement the project. NBI-432-9526-SKC II-8 Y s IK ror- r M ^•l -1 � � r�� ' � a 800'TOTAL ELECTRICAL DEMAND "NOT INCLUDING HEATING DEMAND) 700 - 600 500 • We 300 200 HYDROELECTRIC ENERGY AVAILABLE FOR HEATING DEMAND HYDROELECTRIC POTENTIAL. DOI 390 38 6 ooe REQUIRED DIESELDIRECT ELECTRICAL DEMAND GENERATION ( NOT INCLUDING HEATING 0 - OR CANNERY DEMAND) J F M A M J J A S 0 N D MONTH DETAIL DATA 4000 t 1 3000 / TOTAL COMBINED DEMAND 2000 0 0 -. 1000 TOTAL ELECTRICAL x DEMAND t HYDROELECTRIC 2001 Y POTENTIAL _ a 1985 . co Ww - Ial 0 . J F M A m J J A S 0 N D MONTH OVERALL DATA m-. ,n: .c,_L, f, _... ... a.>. ... �. n.. y'.:Fczr ." ,.: ... X_i. •F rv. ....: cW s. iv:.+.r KING COVE HYDROELECTRIC PROJECT PROJECTED MONTHLY ENERGY GENERATION, DEMAND, AND USAGE FIGURE l � r-�.. ri L-- , - 7 /I UilER3mN WE4R . z �� RENstae�--kµ, ROJECT AREA .PR� Eb ACCESS RgAp L -T A AND TRANSMISSION LINE AIRYTAIP � m r ' 1' "PRP�O$ED RANSNIS.V�iN 11NE - �� i L7� ' KING CO `- / 1�-ems M R E E.�� a - i . PROJECT PLAN m O 2 Z KING BRISTOL BAY COLD BAY OO PRCSTY PEAK , /� S � PASS 3 MILES LOCATION MAP NTS VOI A .IOF L MT NO MT ®TON a KING COVE, O VICINITY MAP NTS SEE ACCESS ROAD AND PENSTOCK CREEK CROSSING DETAILS DIVE-R=SSIIION FA6a6.7F0 40 NSTt90iF AN6-7!\CCESS ROADa�,`J'��L a' �\ '°`•t'O\ \��` ��\u1 `� �'. PLAN SCALE 1 1"- 250' I 50 ACCESS ROAD AND TRANSMISSION LINE TO KING COVE IS MILES) VIA AIRPORT (1/2 MILE) 30 o � � J RING GIRDER \DRESSER COUPLING) �a1 TROC OF ROCK SECTION A RING GIRDER _ 36= / STEEL PIPE NATURAL GROUND (ROCK) SELECT ROADBED FILL SLOE 2% • +A i TOP OF ROCK TYPE I- SIDEHILL (ROCK) BACKFILLED SLOPE 2% TRFNf.N� ROADBED FILL I 36-/ FIBERGLASS PIPE 1 b" SAND BEDDING y I'-O' EACH SIM (TYR) TYPE II - LEVEL GROUND GROUND i TYPE 8 Y /n WO TYPE D � � TYPE D I TYPE ID TYPE D 4]5 - - MMM--- . -----iiV 4]5 PE NSTvCK/ACCESS ROAD TYPES' - ' 12 SELECT ROADBED FILL 450 EL 436 DIVERSION FACILITIES - c - - -- - 450 ��_ LGROUND 425 - 425 SLOPE 2X _ (SOINAMU 400 - - _ 400 COVER I. - : (MIN) ji BACKFILLED TRENCH 575 - 3Y5 36" A FIBERGLASS PIPE 350 —PENSTOCK AND ACCESS ROAD '�. `; o 550 3" SAND BEDDING o.m 325 - �. � 325 ham{ Z 300 --,.. _ -�„ d vi. 300 (TYP) o DELTA CREEK TYPE IQ- SIDEHILL (SOIL) zis �� zis m 25D �,. m ` _ POWERHOUSE 2sa SELECT ROADBED FILL 14'jL2 1 ¢ m _ (NOZZLE EL 215 ) —1� flIPRAP(AS NECES6ARY) zzs ¢ 225 % F o " -�----.,� FLOODPLAIN w W 20azaa OVER(MIN) 175 mOCAL pity.m1]5 MATERIALI30o w m v�i w vLi 150 6' A FIBERGLASS PIPE J W 125 125 'SAND BEDDING o+W 5 10 15 20 25 50 35 4o 43 5o ss TRENCH STATIONING , FEET NOTE' PROFILE OF PENSTOCK /ACCESS ROAD NO TERRAIN WAS ENCOUNTERED REWIRING THE TYPE I SECTION DURING THE FIELD RECONNAISSANCE, SCALE: 1""250' HORIZ. IT IS INCLUDED HERE IN CASE LATER MORE DETAILED I"= Ed VERT. INVESTIGATIONS YIELD EVIDENCE OF SUBSURFACE ROCK. 0 4 6 12 16 20 24 SCALE : I "" 4' 0 50 100 150 200 250 300 SCALE : I" " 50' 0 250 500 750 Iwo 1250 1500 SCALE : I"= 250' TYPE 14'- FLOODPLAIN TYPICAL PENSTOCK /ACCESS ROAD SECTIONS SCALE; 1"-4' CHAIN LINK FENCE I 1I PARKING AREA-- , \ CCNST TION/ACCESS ROAD PERSONNEL DOOR \ Q EQUIPMENT Poo � ENTRANCE DOOR c: \ RI PARKING AREA D i EQUIPMENT MOUNTING SKID POWER TRANSFORMER \ \\ ELECTRICAL SWITCHGEAR FL. EL. 212.0 BURIED Q � TRANSMISSION LINE GENERATOR ENSTOCK�~•� -- -'� 2¢ `` BEARING LUBRICATION SET FLYWHEEL B / ACCESS ROAD / • y 36" DIA. PENSTOCK SPEED INCREASER POWERHOUSE/ V. ryy TURBINE SHUTOFF VALVE ` O B II 6" DIA. PENSTOCK DRAIN RIPRAPPED TAILRACE �� 1 N SLOPE \�= TURBINE 2� 206—�. ^\ RIPflAP �I DELTA CREEK l \ TAILRACE 4`� A•ZQW '• I --*A 30 POWERHOUSE PLAN SCALD I6 GENERAL PLAN SCALE: I'm 20' GENERATOR SPEED INCREASER TURBINE TURBINE EQUIPMENT MOUNTING SKID FENCE 4TAILIACE TURBINE PREFABRICATED WALL SHUTOFF VALVE METAL BUILDING EQUIPMENT DOOR 35'-0° A 36'-0" RIPRAP / FL. EL. 212.0 NATURAL GROUND l AILRACE 36" DIA. PENSTOCK STATE OF ALASKA PROFILE -SECTION A PROFILE -SECTION B ALASKA POWER AUTHORITY SCALE 3 = -0 SCALE: A = 1'-0= 1'-0 ANCHORAGE,ALASKA 16 16 0 3 10 16 20 26 30 KING COVE HYDROELECTRIC PROJECT SCALE : 16" • I'-0 . POWERHOUSE- PLANS AND SECTIONS O 20 40 60 So I00 120 SCALE :I"=20' DOWL ENGINEERS TUDOR ENGINEERING COMPANY ANCHWAGE, ALASKA SAN PRANCISCO,CAUFORNIA PLATE M SECTION III OLD HARBOR SUMMARY INTRODUCTORY NOTE: Presented in this section is the Summary from Volume C-- Feasibility Study for Old Harbor Hydroelectric Project. Included for general background information are several items from that report: Exhibit VI-2, Photographs of the Project Area; Figure VII-3, Projected Monthly Generation, Demand, and Usage; and selected project drawings which include Plate I, the General Plan, Plate III, the Penstock Plan, Profile, and Details, and Plate V, the Powerhouse Plans and Sections. References to figures, exhibits, and plates in the summary presented here refer to items in Volume C, the full feasibility report for the Old Harbor Hydroelectric Project. NBI-432-9526-SOH III-1 OLD HARBOR SUMMARY A. GENERAL Several prior studies of alternative means of supplying Old Harbor with electrical energy recommended a hydroelectric project as the best alternative. As a direct result of these prior studies and recommendations, the Alaska Power Authority authorized a feasibility study to investigate in detail the hydropower potential in the vicinity of Old Harbor. This report summarizes the activities conducted for the feasibility study. These activities included projections of energy needs, formulation of a hydroelectric project plan and an alternative base case plan to meet the electrical energy needs of Old Harbor, detailed analyses of economic feasibility, and preparation of an environmental assessment of the effects of the proposed hydroelectric project. The results of the study indicate that a 340 kilowatt (kW) hydroelectric project can be constructed at Old Harbor, that the project is considerably more economical than the base case alternative, and that the environmental effects of the project are minor. The estimated total construction cost of the proposed Old Harbor hydroelectric project is $3,082,300 in January 1982 dollars. The project could be implemented and on-line by January 1, 19859 if a decision to proceed with the project is made by December 1982. During an average water year, the proposed project would be capable of supplying more than 85 percent of the electrical needs and about it percent of the space heating needs in the project area. The equivalent savings in diesel fuel in the year 2001 would be more than 83,000 gallons for direct electrical demand and more than 19,000 gallons for space heating. NBI-432-9526-SOH III-2 B. AREA DESCRIPTION Old Harbor is a small village located on the southeast coast of Kodiak Island, 50 miles southwest of the city of Kodiak. The selected hydroelectric development site for Old Harbor is located on Midway Creek across Midway Bay from the village. C. POWER PLANNING Power planning for the Old Harbor Project was conducted using standards set forth by the Alaska Power Authority. Previously recommended potential hydroelectric sites were investigated and the project area was surveyed to evaluate potential new sites. After detailed study, a project was selected and then compared with a base case plan. The base case plan consisted of a continuation of the present diesel generation system, enlarged as necessary to meet future growth. Wind generation was also considered as part of the base case. Wind generation was found to be a viable means supplemental generation. Present energy demands for Old Harbor for direct electrical uses and space heating were estimated and future uses in these categories were projected. The projections were based on forecasts of increases in the number of customers and increased usage rates. Population growth and employment, legislation and other political influences, life style changes, and other factors can influence future energy demands, but were not explicitly treated. The period of economic evaluation used was 53 years, beginning in January 1982 and extending for the 50-year life of the hydroelectric project beyond the estimated on-line date of January 1985. The energy demands for Old Harbor were increased NBI-432-9526-SOH III-3 for 20 years starting in January 1982 and extending through December 2001. The demands were then held level over the remainder of the economic evaluation period. For the proposed hydroelectric project, it was assumed that the first priority of use for the energy produced would be for the direct electrical needs of Old Harbor, and remaining energy would be used for space heating to as great an extent as possible. D. DESCRIPTION OF RECOMMENDED HYDROELECTRIC PROJECT Hydroelectric power plants transform the energy of falling water into electrical energy. Generally, a hydroelectric power project consists of a dam to produce the head or to divert stream flows so that they can be passed through a turbine - generator system to produce electric power. In the case of the recommended Old Harbor Hydroelectric Project, a low weir will act as a dam to divert water from Midway Creek through an inlet structure and into a penstock (conveyance pipe). The penstock will be 24 inches in diameter and will carry the water about 2200 feet to the powerhouse, where it will be passed through the turbine -generator system to produce electric energy. The powerhouse will have the capacity to produce 340 kw of electrical power. A transmission line will be constructed to transmit the power generated at the plant to Old Harbor. Access to the powerhouse facilities will be provided by building a new road from Midway Bay to the facilities and by building a dock at the bay. The dock will be reached by boat from Old Harbor. The transmission line will be constructed from the powerhouse across the upper end of Midway Bay to Old Harbor. The general plan and features of the proposed project are presented on Plates I through VI of Appendix A. Photo- graphs of the project area appear in Exhibits VI-1 through VI-4 at the end of Section VI and in the Environmental Report, AppPridix E. NBI-432-9526-SOH III-4 Under the recommended plan, energy generated by the hydro- electric plant will have to be supplemented by diesel genera- tion. The entire existing diesel capacity will be required as standby and backup power. The hydroelectric generation will be adequate to meet the direct electrical needs of Old Harbor during most of the year; however, during periods from the end of November to the first of April it will be necessary to supplement the hydroelectric generation with diesel power. In all, during an average water year the proposed hydro- electric project will be capable over the project life of supplying an average of more than 90 percent of the electrical needs of Old Harbor and approximately 15 percent of the space heating requirements. Average annual energy production from the hydroelectric plant will be 1.31 millio❑ kilowatt-hours (kWh) and the average annual plant factor will be about 44 percent, which means that the plant is expected to generate about 44 percent of the energy that it could produce if the turbine -generator unit was operated continuously at full capacity. E. BASE CASE PLAN The base case plan formulated to meet the projected energy demands of Old Harbor assumed that the existing diesel system would continue to be used as the sole source of electric power. Because there are no significant heating loads near the plant, it was assumed that the system would not incorporate waste heat recovery that would be used for space heating, since it probably would not be economical to relocate the plant nearer a heating load. The existing diesel plant's capacity was judged to be adequate to meet peak demands on the Old Harbor system throughout the period of study. NBI-432-9526-SOH III-5 F. ECONOMIC ANALYSIS The economic analysis was based on the Alaska Power Authority criteria that compare the net present worth of the base case costs to the net present worth of the proposed hydro- electric project costs using specified real price escalation and discount rates. Net present worth is the present value of the costs that would be incurred over a comparable economic evaluation period of 53 years for both projects. All costs other than the cost of the hydroelectric project and diesel supplement were considered as adjustments to the base case cost. The present worth of the total costs of the base case plan is $8,182,800. If this cost is reduced by the wind energy credit of $330,400, the net present worth is $7,852,400. Adding the space heating credit at $1,234,600 results in a final net present worth of $9,087,000. For the proposed hydroelectric project, the present worth of the costs is $6,475,000. A comparison of this net present cost with the base case net present costs indicates that the recommended hydroelectric project is considerably more economical than the alternative base case. An additional measure of project feasibility is the bene- fit/cost (B/C) ratio. The B/C ratio is the present worth of the project benefits divided by the net present worth of the project costs. For this project, the calculated B/C ratio is 1.264 when the hydroelectric energy used only for the direct electrical needs of Old Harbor is compared to the base case only and 1.213 when the wind energy credit is included. Inclusion of the space heating credit results in a final B/C ratio of 1.403. These B/C ratios indicate that the proposed hydroelectricproject is highly feasible. NBI-432-9526-SOH III-6 The unit costs for each year of operation for both the base case and the hydroelectric alternative were calculated and compared in order to determine the optimum timing for project development. This analysis indicates that the project is viable for immediate development. G. ENVIRONMENTAL AND SOCIAL EFFECTS The study results indicate that the adverse environmental effects of the project will be minor due to the limited scope of project activities, the limited nature of the fishery resources in Midway Creek, and the availability of measures to mitigate the potential effects from the construction and operation of the facilities. Implementation of the project should bring some socioeconomic benefits to Old Harbor. The local payroll will be expanded during construction and some employment should be provided for local residents both for construction and maintenance of the facilities. The project should also bring a dependable and cheaper supply of electric power to the local residents. H. CONCLUSIONS AND RECOMMENDATIONS The studies conducted for this report indicate that the proposed 340 kW hydroelectric project is feasible and that the energy demands of Old Harbor are sufficient to utilize the hydroelectric plant's planned capacity. The proposed project is a more economic means of meeting the area's future electric needs than the base case diesel alternative. - Environmental effects of the proposed project are minor. In view of these findings, it is recommended that actions be initiated to implement the project. NBI-432-9526-SOH III-7 Z-IA lIHIHX3 N ADO 3snOHN3MOd 'R V.'d`� � { Fa' y 6, jr •T �I:� ,.�..� r.-.r^:3. jy .`S, n�+ � i Y�� 'r �.� ' •*, l�.f'.,�Y^ t tee 4%Z `� •^ ay y , f 'C'y, lYia- r ' R d13M NOISd3AI0 '1SV3Hinos 9NIHOOI '31IS 103f Odd 30 SVWVdOWVd d13M NOIS83AIC 2- 3anoiA 3J,isn (INV `ONdW30 `NO11b83N30 AO33N3 AlH1NOW 03103m8d 103rO8d 0181331308CI1H 80138VH a10 VIVO lIV83AO H1NOW 0 N 0 s V r r w v W 3 r 0661 �.►� ` 001 IOOZ / 1VI1N310d ONVW30 % 318133130,80AH 1V318103-13 ooz ivioi 002 �� \ OOb 61 oo5 i l es 009 \ 0OL 1 0NVW30 03N19WOO 1V101� % J 008 _. - 006 _ 0001 m z m x- s x 0 0 0 VIVO -1Ib130 a N 0 s d r r W v 9e1'00�`// , 066 .00,�� % \ �100Z 1VI1N310d 318133-13060AH (INVW30 ON11V3H 1331N Ol 318V-1IVAV AOa3N3 3161331308CAH' H1NOW w q r 0 NOIlV83N39 OZ 13S310 038inO38, / - ob 09 08 F 001 031 (ONVA30 ONIIV3H EJNIOf110N1 lON) Obi V0121I33-13 133810 m 081 _. .. 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NOO1SN3d O,bZ 99'13'ld _ — _ 13A31 aNnoa9 9xuSIz3 3AlIA 3301nHS 3NISWI (311W Z 7 N000 Atl8 AtlM01W Dl oVOa 91 0-,I = F' 31tlo5 V N01103S-3lIjOHd ,OZ=,I :3ltloS NVld�H3N39 SECTION IV LARSEN BAY SUMMARY INTRODUCTORY NOTE: Presented in this section is the Summary from Volume D-- Feasibility Study for Larsen Bay Hydroelectric Project. Included for easy reference are several items from that report: Exhibit VI-1, photographs of the project area; Figure VII-3, Projected Monthly Generation, Demand, and Usage; and selected project drawings which include Plate I, the General Plan, Plate III, the Penstock Plan, Profile, and Details, and Plate V, the Powerhouse Plans and Sections. References to figures, exhibits, and plates in the summary presented here refer to items in Volume D, the full feasibility report for the Larsen Bay Hydroelectric Project. NBI-432-9526-SLB IV-1 LARSEN BAY SUMMARY A. GENERAL Several prior studies of alternative means of supplying Larsen Bay with electrical energy had recommended a hydro- electric project as the best available source. As a direct result of these prior studies and recommendations, the Alaska Power Authority has authorized a feasibility study to investigate in detail the hydropower potential in the vicinity of Larsen Bay. This report summarizes the activities conducted for the feasibility study. These activities included projections of energy needs, formulation of a hydroelectric project and an alternative base case to meet the electrical energy needs of Larsen Bay, detailed analyses of economic feasibility, and preparation of an environmental assessment of the effects of the project. The results of the study indicate that a 270 kilowatt (kW) hydroelectric project can be constructed at Larsen Bay, that the project is considerably more economical than the base case alternative, and that the environmental effects of the project are minor. The total cost of the proposed Larsen Bay hydroelectric project is $2,821,400 in January 1982 dollars. The project could be implemented and on-line by January 1, 1985, if a decision to proceed with the project is made by December 1982. During an average water year, the proposed project would be capable of supplying more than 85 percent of the electrical needs and about 14 percent of the space beating needs in the project area. The equivalent savings in diesel fuel in the year 2001 would be about 69,000 gallons for direct electrical demand and 16,000 gallons for space heating. NBI-432-9526-SLB IV-2 B. AREA DESCRIPTION The village of Larsen Bay is located near the junction of two fjords, Larsen Bay and Uyak Bay, on the northwest coast of Kodiak Island. Shelikof Strait, separating Kodiak Island from the mainland, lies 14 miles to the northwest and the city of Kodiak lies 60 miles to the east. The selected hydroelectric power site is on Humpy Creek, a small tributary of Larsen Bay fjord about one mile south of town. The general project area and the proposed project site are shown on Plate I of Appendix A. C. POWER PLANNING Power planning for the Larsen Bay project was conducted using standards set forth by the Alaska Power Authority. Previously recommended potential hydroelectric sites were investigated and the project area was surveyed to evaluate potential new sites. After detailed study, a project was selected and then compared with a base case plan. Present energy demands for Larsen Bay for direct electrical uses and space heating were estimated and future uses in these categories were projected. The projections were based on forecasts of increases in the number of customers and increased usage rates. Population growth and employment, legislation and other political influences, life style changes, and other factors ca❑ influence future energy demands but they were not explicitly treated. The period of economic evaluation used was 53 years, which starts in January 1982 and extends for the 50-year life of the hydroelectric project after the estimated on-line date of January 1985. The energy demands for Larsen Bay were increased for 20 years starting in January 1982 and extending through NBI-432-9526-SLB IV-3 December 2001. The demands were the❑ held level over the remainder of the economic evaluation period. For the proposed hydroelectric project, it was assumed that the first priority of use for the energy produced would be the direct electrical needs of Larsen Bay, and any remaining energy would be used for space heating. D. DESCRIPTION OF RECOMMENDED HYDROELECTRIC PROJECT Hydroelectric power plants transform the energy of falling water (head) into electrical energy. Generally, a hydroelec- tric power project consists of a dam to produce the head or to divert stream flows so that they can be passed through a turbine -generator system to produce electric power. In the case of the recommended Larsen Bay Hydroelectric Project, a low weir will act as a dam to divert water from Humpy Creek through an inlet structure and into a penstock (conveyance pipe). The penstock will be 27 inches in diameter and will carry the water about 2700 feet to the powerhouse, where it will be passed through the turbine -generator system to produce electric energy. The powerhouse will have the capacity to produce 270 kw of electrical power. A transmissio❑ line will be constructed to transmit the power generated at the plant to Larsen Bay. Access to the powerhouse facilities will be provided by building a short length of new road to link up with an existing road that extends to an existing and abandoned dam near the site of the new powerhouse. The transmission line will follow the alignment of the new access road and the existing road to Larsen Bay. The general plan and features of the proposed project are presented on Plates I through VII of Appendix A. Photographs of the project area are presented in Exhibits VI-1 through VI-4 at the end of Section VI and in the Environmental Report, Appendix E. NBI-432-9526-SLB IV-4 Under the recommended plan, energy generated by the hydro- electric plant will have to be supplemented by diesel genera- tion. Larsen Bay does not currently have a central diesel generating plant and the plan will therefore require the construction of diesel facilities for standby and backup power. The hydroelectric generation will be adequate to meet the direct electrical needs of Larsen Bay during most of the year; however, from December through March diesel will be needed to supplement the hydroelectric generation. A new electrical distribution system will also be required since none currently exists. During an average water year the proposed hydroelectric project will be capable of supplying more than 90 percent of the electrical needs of Larsen Bay and approximately 20 percent of the space heating over the life of the project. Average annual energy production from the hydroelectric plant will be 1.09 million kilowatt-hours (kWh) and the average annual plant factor will be about 46 percent, which means that the plant is expected to generate about 46 percent of the energy that it could produce if the turbine -generator unit was operated continuously at full capacity. E. BASE CASE PLAN The base case plan formulated to meet the projected energy demands of Larsen Bay assumed that the use of individual existing diesel generating plants would be discontinued and a new centralized diesel generating plant would be constructed. Because of apparent economic benefits, it was assumed that the proposed system would also incorporate waste heat recovery that would be used for space heating. The possibility of installing wind generation equipment was also considered, and was found to be economically viable. NBI-432-9526-SLB IV-5 It was assumed that the diesel system for the 1982 base case would require about 51,500 gallons of fuel oil per year; this amount was expected to increase over the next 20 years to more than 80,000 gallons per year. Waste heat recovery was expected to displace the use of 17,000 gallons of fuel oil per year by the year 2001. The wind generators are expected to displace about 12,000 gallons of oil by 2001. F. ECONOMIC ANALYSIS The economic analysis was based on the Alaska Power Authority criteria that compare the net present worth of the proposed base case costs to the net present worth of the pro- posed hydroelectric project costs using specified real price escalation and discount rates. Net present worth is the present value of the costs that would be incurred over a comparable economic evaluation period of 53 years for both projects. The present worth of the base case only, that is, diesel generation, is $7,532,100. If this cost is reduced by the savings that could be realized from the installation of waste heat recovery, the present worth is $6,725,100; further reducing this cost by the benefit obtainable from wind generation yields a present worth of $6,432,000. All costs except the cost of the hydroelectric project and its diesel supplement were considered as adjustments to the base case. The cost of the space heating credit was added to the base case because it represents a benefit that would not be realized if the base case plan was implemented. The next present worth of the base case after all adjustments is $7,348,600. For the proposed hydroelectric project, the present worth of the costs, is $5,941,700. A comparison of this net present cost with the base case net present costs indicates that the NBI-432-9526-SLB IV-6 recommended hydroelectric project is considerably more economical than the alternative base case. An additional measure of project feasibility is the bene- fit/cost (B/C) ratio. The B/C ratio is the present worth of the project benefits divided by the net present worth of the project costs. For this project, the B/C ratio for the base case only is 1.268. The B/C ratio after adjustment for waste heat recovery is 1.132; after additional adjustment for wind generation, the B/C ratio is 1.067; and after all adjustments, the B/C ratio is 1.237. These B/C ratios indicate that the proposed hydroelectric project is highly feasible. G. ENVIRONMENTAL AND SOCIAL EFFECTS The environmental study results indicate that the effects of the project will be minor due to the limited scope of the project activities, the inability of salmon to spawn above the old diversion dam on Humpy Creek, the abundance of alternative areas available for trapping, hunting, and general recreation, and the availability of measures to mitigate potential effects from the construction and operation of the facilities. Minor socioeconomic benefits will occur as a result of project construction and maintenance and cheaper electric rates made possible by the project. Additional environmental studies do not appear to be warranted unless regulatory agencies or local residents express additional concerns. H. CONCLUSIONS AND RECOMMENDATIONS The studies conducted for this report indicate that the proposed 270 kW hydroelectric project is feasible and that the energy demands of Larsen Bay are sufficient to utilize the hydroelectric plant's planned capacity. The proposed project is a more economic means of meeting the area's future electric needs than the base case diesel alternative. Environmental effects of the proposed project are minor. NBI-432-9526-SLB IV-7 In view of these findings, it is recommended that actions be initiated to implement the project. NBI-432-9526-SLB IV-8 POWERHOUSE DIVERSION WEIR VILLAGE OF LARSEN BAY, LOOKING NORTH FROM UPPER HUMPY CREEK. THE POWER PROJECT IS LOCATED IN THE LOWER CANYON NEAR THE CENTER OF THE PHOTO. EXHIBIT VI-1 200 180 HYDROELECTRIC ENERGY AVAILABLE FOR SPACE HEATING — — , WE* 140 DIRECT ELECTRICAL DEMAND(NOT INCLUDING HEATING 120 DEMAND) 100 l 80 / \ HYDROELECTRIC POTENTIAL �\ N 2001 / 1 _ V so ` /'sso / 40 � 1986 REQUIRED DIESEL , 20 GENERATION v J F M A M J J A S O N D MONTH DETAIL DATA 2001500 � C \ TOTAL COMBINED DEMAND f lk 400 ` 1990 300 \j 1985 200 ` I HYDROELECTRIC POTENTIAL — I TOTAL ELECTRICAL 100 DEMAND ^ \ ✓ / 1990 2001 1985 0 J F M A M J MONTH A S O N U OVERALL DATA LARSEN BAY HYDROELECTRIC PROJECT PROJECTED MONTHLY ENERGY GENERATION, DEMAND, AND USAGE FIGURE �/ 1 0 M U; 'N 4 0,4F A L iY A Y IJ Iu r A K --oo B A Y Cabins Anc,e, ca� Co (Ab6i 'd) File z S L A 35 Pi PROJECT PLAN 0 1 T 11 3 1 1 1 4 4 Iil MILES LOCATION MAP NOT TO WALE VICINITY MAP NTS Div FAC ri ALKWAY SURFACE kEONCRET9 ENCASEMENT HUMPY CREEK PE 6 PENSTOCK TOP OF ROOK TYPE Di- CONCRETE ENCASED PENSTOCK/ ACCESS ROAD TYPE CONCRETE ENCASED ROADWAY IS STREAMSED, EL 386.5 TT-Y�PE—IQ TYPE I PENSTOCK INSTALLATION TYPE I TYPE III TYPE II 390 +-F Sea 370 30 350 24"(/jPENSTOC,K' . 40 330 f T f 320 \ o 310300 4 HUMPY rREEK 280 J \\ 260 20 \ \\\\ 240230 220 O \ w O 210 Q WN 330 320 310 300 290 260 270 260 250 240 230 220 O 3 < OHOVSE 210 200 E m S O NOZZLWERE El 19S 200 ABANDONED CAN 0.00 1+00 2+00 3W0 4+00 5.00 6.00 i+00 9+00 9.00 10+00 Ib00 12.00 13+00 14.00 I6+00 AHON 17+00 16+00 19`00 20+00 21+00 22+00 23400 24+00 25+00 26+00 2N00 2W00 29W0 STATIONING FT NOTE- MEAN SEALEVEL ELEVATION = IOOft 3 SITE DATUM PROFILE OF PENSTOCK/ACCESS ROAD RING GIRDER SCALE • 1' • 100' HORIZ. I"• 20' VERT. 27"/ STEEL PIPE RING GIRDER 12, 1 `�� NATURAL GROUND (ROCK) ` 12' SELECT ROADBED FILL IX2ESSER �� BACKFILLED COOPLING SELECT ROADBED FILL TRENCH SLOPE 2% _ �— SLOPE 25L IS NATURNATURGROUND SLOPE �2% 3'COVER F3"MAND ROADBED FILL NATURAL 1 (MIN.) GROUND(SOIL) 31 COVERu• ., v✓ I' (MIT BACKFILLED TRENCH WBERGLASS PIPE i 2T"/ FIBERGLASS PIPE TOPOF ROCK Jl TOP OF ROCKA BEDDING SECTION q 12' ---i I 1 EACH SIDE " SAND REDOING �- '-O( ITYP) i TYPE I- SIDEHILL (ROCK) TYPE II - LEVEL GROUND O.D..2'-O" TYPE IQ- SIDEHILL (SOIL) (TYP) TYPICAL PENSTOCK / ACCESS ROAD SECTIONS 0 4 B 12 16 20 24 SCALE; 1'"4' SCALE: 1"• 4' _...ANCHOR BLOC �A BEARING LUBRICATION SET TOO . \ \ PRESSURE SET Pp \ _\ r GOVERNOR 27"DIA. PENSTOCK Y� `' �-. In B M1 TURBINE SHUTOFF VALVE I — \ 1 ---- TURBINE 6"DIA PENSTOCK GRAIN �-_-- -_ TAILRACE ABANDONED DAM ELECTRICAL SWITCHGEAR \ SPEED INCREASER FLYWHEEL PE STOCK I FLOOR EL 192 GENERATOR ABANDONED WOOD STAVE 111 PENSTOCK K EQUIPMENT MOUNTING SKID 1 m\\ PERSONNEL DOOR I y I OW RN U I•f \\ ''•GA T I \�\ ~ EQUIPMENT DOOR J LA SWITCHYARD PARKING AREA I I I I I- \ 1 1 I I I I c�-'• - /J I r r l I / r PLAN ry / ACCESS I • A ROAD 1 / SCALES 6• I�0 N A CONCRETE MAT FOR / •� •\ CREEK CROSSING CONSTRUCTION/ACCESS ROAD �o TRANSMISSION LINE GENERAL PLAN SCALE- I"-20' TURBINE SPEED INCREASER GENERATOR TURBINE- TURBINE - ANCHOR BLOCK TURBINE SHUTOFF VALVE PREFABRICATED METAL BUILDING a H1 EQUIPMENT MOUNTI G 7LPARKING AREA SKID _ SELECT MATERIAL NATURAL GROUND y!. TAILRACE TAILRACE SLOPE STATE OF ALASKA ALASKA POWER AUTHORITY ANCHORAGE,ALASKA PROFILE— SECTION A PROFILE— SECTION B 0 3 10 13 20 26 30 SCALE! 16•I'—O SCALE+3•• LARSEN BAY HYDROELECTRIC PROJECT 0 16 SCALE 16 I'-p POWERHOUSE -PLANS AND SECTIONS 0 20 40 60 Bo 100 120 SCALE1"- 20'-0 00W1_ ENGINEERS TUDOR ENGINEERING COMPANY ANCHORAGE, ALASKA SAN FRANCISCO, CALIFORNIA PLATE V SECTION V TOGIAK SUMMARY INTRODUCTORY NOTE: Presented in this section is the Summary from Volume E-- Reconnaissance Study for Togiak Hydroelectric Project. Included for general background information are several items from that report: Exhibit VI-1, Photographs of the Project Area; Figure VII-4, Projected Monthly Generation, Demand, and Usage; and selected project drawings which include Plate I, the General Plan, and Plate II, Alternative A - Plans and Sections. References to figures, exhibits, and plates in the summary presented here refer to items in Volume E, the full feasibility report for the Togiak Hydroelectric Project'. NBI-432-9526-ST V-1 TOGIAK SUMMARY A. GENERAL Several prior studies of alternative means of supplying the Togiak area with electrical energy had recommended a hydroelec- tric project as the best source. As a direct result of these prior studies and recommendations, the Alaska Power Authority authorized a reconnaissance -level feasibility study to investi- gate in detail the hydropower potential in the vicinity of Togiak. This report summarizes the activities conducted for the reconnaissance study. These activities included projections of energy needs, formulation of alternative hydroelectric projects and a hypothetical base case to meet the electrical energy needs of Togiak, detailed analyses of economic feasibility, and preparation of an environmental assessment of the effects of the project. The results of the technical studies conducted indicate that a 432 kilowatt (kW) hydroelectric project utilizing a 38- foot-high concrete dam could be constructed on the Quigmy River to meet the electric demands of Togiak. However, the results of the economic analyses indicate that the hydroelectric project would have only marginal feasibility. An additional project on the Kurtluk River is currently under investigation. The results of this investigtion will be presented in a subsequent report. The total cost of the proposed Togiak hydroelectric project is $7,047,200 with the 4.6-mile road option and $8,169,600 with the 11.6-mile road in January 1982 dollars. The project could be implemented and on-line by January 1, 1985, if a decisio❑ to NBI-432-9526-ST V-2 proceed with the project is made by December 1982. During an average water year, the proposed project would be capable of supplying about 99 percent of the electrical needs and about 30 percent of the space heating needs in the project area. The equivalent savings in diesel fuel in the year 2001 would be 144,000 gallons for direct electrical demand and 44,000 gallons for space heating. B. AREA DESCRIPTION Togiak is a small village located on Bristol Bay about 70 miles west of Dillingham and 400 miles southwest of Anchorage. The hydroelectric site selected for detailed study is on the Quigmy River about 12 miles west of Togiak. The smaller village of Twin Hills, four miles east of Togiak, was included i❑ the assessment of the future power needs of the area. C. POWER PLANNING Power planning for the Togiak Project was conducted using standards set forth by the Alaska Power Authority. Previously recommended potential hydroelectric sites were investigated and the project area was surveyed to evaluate potential new sites. After detailed study, a project was selected and then compared with a base case plan. The base case pla❑ consisted of a continuation of the present diesel generatio❑ system, enlarged as necessary to meet future growth. The installation of waste heat recovery equipment and wind generators was also considered as part of the base case plan. Present energy demands for Togiak for direct electrical uses and space heating were estimated and future uses in these same categories were projected. The projections were based on forecasts of increases i❑ the number of customers and increased usage rates. Population growth and employment, legislation and NBI-432-9526-ST V-3 other political influences, life style changes, and other factors can influence future energy demands but were not explicitly treated. The period of economic evaluation used was 53 years, which starts in January 1982 and extends for the 50-year life of the hydroelectric project after the estimated on-line date of January 1985. The energy demands for Togiak were increased for 20 years starting in 1982 and extending through December 2001. The demands were then held level over the remainder of the economic evaluation period. As stated, the neighboring community of Twin Hills was included in estimating future energy demands. For the proposed hydroelectric project, it was assumed that the first priority of use for the energy produced would be for the direct electrical needs of the Togiak area, and any remain- ing energy would be used for space heating. D. DESCRIPTION OF RECOMMENDED HYDROELECTRIC PROJECT Hydroelectric power plants transform the energy of falling water into electrical energy. Generally, a hydroelectric power project consists of a dam to produce the head or to divert stream flows so that they can be passed through a turbine - generator system to produce electric power. In the case of the alternative projects considered to bring hydroelectric power to Togiak, three dam configurations and two access road options were evaluated. These are described below. All three of the dams considered would divert water from the Quigmy River through an intake structure and pass the water through a tur- bine -generator system to produce electric energy. An access road would be constructed from Togiak to the project facilities and a transmission line would be constructed along the access road alignment to transmit the power generated at the plant to Togiak. NBI-432-9526-ST V-4 The general plan and features of the recommended hydroelec- tric project are presented in the plates of Appendix A. Photo- graphs of the project area are presented in Exhibits VI-1 through VI-3 of Section VI and in pages 2, 10, and 15 of Appendix E. The site selected for investigation was a narrow canyon suitable for either a concrete or rockfill dam. Since both types were apparently technically feasible, two concrete dams (38 and 28 feet high) and one rockfill dam were investigated to evaluate their economic feasibility and confirm their technical feasibility. Although the Quigmy River above the proposed dam site locations might not be a major spawning area, the preliminary designs for all three dam alternatives incorporated fish ladders to allow for fish passage. An 11.6-mile road would be required to provide access from Togiak to the proposed facilities. The Alaska State Department of Transportation and Public Facilities, Division of Aviation, is investigating the possibility of building a road along the first seven miles of the proposed access road alignment in order to reach a gravel source needed to construct an airport to serve Togiak. Two possibilities exist for obtaining an access road for the proposed hydroelectric project: 1. The entire 11.6-mile road would be built as part of the hydroelectric project. 2. The Alaska Department of Transportation would build the first seven miles of the road and the hydroelec- tric project would build the remaining 4.6 miles. The investigations conducted during this study indicate that the most favorable combination, and indeed the only one that could be economically feasible, is the 38-foot-high concrete dam with only 4.6 miles of the access road being funded by the project. NBI-432-9526-ST V-5 E. BASE CASE PLAN The base case plan formulated to meet the projected energy demands of Togiak assumed that the existing diesel system would continue to be used as the sole source of electric power. It was also assumed that the system would be modified to incorpor- ate waste heat recovery that would be used for space heating. Wind generation would also be installed as part of this plan. The existing diesel plant's capacity was judged to be adequate to meet peak demands on the Togiak system throughout the period of study. The forecasted energy demands for the base case included the requirements for Twin Hills. F. ECONOMIC ANALYSIS The economic analysis was based on the Alaska Power Authority criteria that compare the net present worth of the base case costs to the net present worth of the alternative proposed hydroelectric project costs using specified real price escalation and discount rates. Net present worth is the present value of the costs that would be incurred over a comparable economic evaluation period of 53 years for both projects. The net present worths of the base case are as follows: Base Case Only Waste Heat Credit Subtotal Wind Energy Credit Subtotal Space Heating Credit Total Alternatives A & C $11,027,600 999,400 10,028,200 540,700 9,487,500 2,463,000 $11,950,500 NBI-432-9526-ST V-6 Alternative B -.$111027,600 999,400 10,028,200 540,700 9,4879500 1 234,800 17221,300 I The space heating credit was shown as an increase in cost to the base case so that all present worths could be compared to the hydroelectric project standing alone. For the three alternative hydroelectric projects studied, the present worth of the costs is as follows: Alternative A Alternative B Alternative C W/11.6-Mile ,Road $12,758,400 13,037,400 13,257,700 W/4.6-Mile Road $11,668,600 11,947,600 12,167,900 As can be noted from the table, the only hydroelectric alternative with a lower present worth cost than the base case is alternative A, and then only if the 4.6-mile roadway can be constructed. An additional measure of project feasibility is the bene- fit/cost (B/C) ratio. The B/C ratio is the present worth of the project benefits divided by the net present worth of the project costs. For the alternative studies for this project, the calculated B/C ratios were as follows: B/C Ratio B/C Ratio W/11,6-Mile Road W/4.6-Mile Road Alternative A 0.937 1.024 Alternative B 0.822 0.897 Alternative C 0.982 _. 0.901 NBI-432-9526-ST V-7 These results indicate that Alternative A, the 38-foot-high concrete dam with 432 kW installed capacity, is marginally feasibile only if the Alaska Department of Transportation con- structs the first 7.0 miles of the required 11.6-mile access road. If the entire 11.6-mile road must be constructed, the project is a break-even proposition. G. ENVIRONMENTAL AND SOCIAL EFFECTS The study results indicate that a hydroelectric project at the Quigmy site could have potentially serious environmental impacts, but measures such as fish ladders could likely miti- gate the most serious effects. Additional studies are recom- mended to answer questions related to the downstream effects of the dam impoundment on salmon spawning; coho (silver) salmon runs; minimum water requirements for fish below the proposed dam; selection of a suitable access route; and methods to ensure safe passage of out -migrating young salmon. Additional study of fish passage facilities is also recommended. H. CONCLUSIONS AND RECOMMENDATIONS The studies conducted for this report indicate that a marginally feasible project consisting of a 38-foot-high concrete dam with 432 kW installed capacity could be con- structed at the Quigmy River site. The next step in project implementation, the preparation of a Definitive Project Report to optimize the project features, should be pursued only if the Alaska Department of Transportation constructs the initial 7.0 miles of the necessary 11.6-mile-long access road. A more detailed investigation of a much smaller hydroelec- tric site on the Kurtluk River three miles from Togiak could be pursued, but the project would meet only a small portion of the Togiak electric demands. The site is currently being investi- gated at a preliminary level and will be addressed in a subsequent letter report. NBI-432-9526-ST V-8 5 TOGIAKIS QUIGMY RIVER DAM SITE: AIR PHOTO LOOKING UPSTREAM. THE DAM AXIS IS ACROSS THE NARROW CHANNEL IN CENTER OF THE PHOTO, _ EXHIBIT VI-1 TOGIAK HYDROELECTRIC PROJECT PROJECTED MONTHLY ENERGY GENERATION, DEMAND, AND USAGE INSTALLED CAPACITY = 432 kW FIGURE M-4 BORROW SV7E `TOGIAK $ , K ~ � PROPOSED ACCESS ROAD PROPOSEEXISTING ROAD RA ANDSMI CANNERY : TWIN HILLS -' - AND TRANSMISSION LINE PROPOSED TRANSMISSION LINE � x. / �r T O G/ A K B A Y PROJECT PLAN LOCATION MAP NOT TO SCALE VICINITY MAP NOT TO SCALE 0 z MILES I i TOCK OE SWI RD PARKING AREA El FLOW \l SPILLWAY 200 ETE GRAVITY SLOCK6 \ GENERAL PLAN SCALE 0- 20 SHUT-OFF q26 DVERHAN 1�1 - REM_ -1.31----FISH LADDER A \ TUR6INE CONTROL PANELS Ililllllllll POWERHOUSE PLAN NTS B INCREASER GROUND o FLOOD -- o RES. E STR€AMSED-f L. I70 _ _ SECTION A SCALE • 1"• 10' SECTION B SCALE - I" - 10' 0 10 20 30 40 SO 60 SC LE I .. 10 0 20 40 60 SO 100 120 SCALE - I- • 2d