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HomeMy WebLinkAboutStony River Reconnaissance Study of Energy Requirements & Alternatives 1981 OF ENERGY REQUIREMENTS & ALTERNATIVES FOR STONY RIVER INTERNATIONAL ENGINEERING COMPANY, INC. A MORRISON-KNUDSEN COMPANY ROBERT W. RETHERFORD ASSOCIATES DIVISION EAL AonA POWER AUTHORITY 3 STONY RIVER SUPPLEMENT TO RECONNAISSANCE STUDY OF ENERGY REQUIREMENTS AND ALTERNATIVES FOR - BUCKLAND, CHUATHBALUK, CROOKED CREEK HUGHES, KOYUKUK, NIKOLAI, RED DEVIL, RUSSIAN MISSION, SHELDON POINT, SLEETMUTE, STONY RIVER, TAKOTNA AND TELIDA MAY 1981 Prepared by: Robert W. Retherford Associates Arctic Division of International Engineering Co., Inc. Anchorage, Alaska For the State of Alaska Department of Commerce and Economic Development Division of Alaska Power Authority 333 West Fourth Avenue, Suite 31 Anchorage, Alaska 99501 Under Contract No. AS44.56.010 APA 20/T1 This report was prepared by: Robert W. Retherford Associates Arctic Division of International Engineering Company R.W. Retherford, P.E. Frank J. Bettine, E.1.T. James J. Lard, E.1.T. Mark Latour, Economist Illustrations on the front cover were prepared and sketched by Kathryn L. Langman. These illustrations portray several energy resource alternatives investigated for the Thirteen Villages included in this study. APA 20/T2 Section no fF WHY HF APPENDIX A APA*32C1 TABLE OF CONTENTS Summary and Results Recommendations Existing Conditions and Energy Balance Energy Requirements Forecast Resource and Technology Assessment Energy Plans Description of Selected Technologies Page 1.4 2.1 Sail 4.1 5.1 6.1 SECTION 1 SUMMARY AND RESULTS APA*32C2 SECTION 1 SUMMARY AND RESULTS A. SUMMARY A study was recently conducted under contract number AS44.56.010 for the State of Alaska Department of Commerce and Economic Development, Divi- sion of Alaska Power Authority to determine the energy alternatives for Thirteen Western Alaskan Villages. This study consists of establishing the following: Energy Balance for 1979 Existing Power and Heating Facilities - 1980 Electric Power Requirements to the year 2000 Space Heating Requirement to the year 2000 Potential Energy and Electric Power Resources Evaluation of the Electric Power Resources Recommendations for the development or future studies for the 13 Western Alaskan villages of Buckland, Hughes, Koyukuk, Telida, Nikolai, Takotna, Stony River, Sleetmute, Red Devil, Crooked Creek, Chuathbaluk, Russian Mission and Sheldon Point (See Figure 1.1). The Stony River supplement represents a brief summary of the most perti- nent facts and findings contained in the original report which relate to the village of Stony River. Detailed data concerning the village may be obtained by referring to the original report. Diesel fuels are presently used to satisfy the major percentage of energy demands in the village. Emphasis in the study was therefore placed on possible resources and technologies that could replace or at least supple- ment the use of increasingly costly fuel oil. The energy alternatives which were selected for detailed evaluation in the village of Stony River include:? 1) Diesel generation 2) Waste Heat Recovery 3) Binary Cycle generation using wood fuel 4) Passive solar heating 5) Energy conservation 1 See Appendix A for brief description of technologies listed. i=l APA34*C1 BARROW OCR, 1 BUCKLAND / 2. HUGHES / 3 KOYUKUK / 4 RUSSIAN MISSION eT a 5 SHELDON POINT oa ; iB 6 CHUATHBALUK we 7 7 CROOKED CREEK aio" 8 NIKOLAI 9 RED DEVIL Yuhon— Tenane Patou 10 SLEETMUTE | 11 STONY RIVER Lote ‘a 12 TAKOTNA Aloe ven te Range \ 13 TELIDA wach 13 2 es ¢ ‘Susine R. | i Tol aw ' Fo th Or v River | 73 File, Movies me “in oy 9 901; a QP 1 6 tog diets "Ming, | ¢ BE Oo 2 i ? ANCHORAGE \ s Tike at 9 c . takes ee ott oy or S_yeh wed 2 ve u x Lo DP 4 YAKUTAT q = 7 S ‘ UNEA Cult of Aloske ». at | ve \s » Ss 4 Bristos 89 KODIAK PACIFIC OCEAN as 4b su bh Co ho ad FIGURE 1.1 we 4 ee os ALASKA MAP 13 WESTERN VILLAGES SECTION 1 SUMMARY AND RESULTS To obtain a comprehensive understanding of future energy requirements for the village, a control year - 1979 - was established from which all projections have been made. Information related to village history, population and economic conditions, plus information regarding village government, transportation, power and heating facilities, fuel require- ments, etc., was collected to provide the necessary background data to support these projections. B. EVALUATION RESULTS dy Economics Table 1.1 is a summary of the 20-year economic evaluation performed for the combination of alternatives (i.e., energy plans) selected for detailed study for Stony River. This Table lists the accumulated present worth of plan costs and the accumulated present worth of the net benefits derived from non-electrical outputs, where: 1) Plan costs represent the cost for providing electrical generation, and 2) Net benefits represent the savings derived from waste heat capture or surplus hydroelectric energy used for electric heating. a. Twenty Year Evaluation Results Results of the 20-year economic evaluation indicate that the use of diesel with waste heat recovery to be most economical energy plan examined for Stony River. The diesel generation plus binary generation with waste heat energy plan averaged approximately 33 percent greater cost than the diesel generation plus waste heat recovery plan for Stony River. 1-3 APA34*C3 ork STONY RIVER Table 1.1 Accumulated Present Worth of Plan Costs and Benefits ($1,000) Diesel Diesel & & Diesel Binary Cycle Diesel WECS PERIOD & & & & Waste Heat Waste Heat Hydroelectric Waste Heat Cost-Benefit Cost-Benefit Cost-Benefit Cost-Benefit 20-year 1282-122.9 1717-88.7 N/A N/A SECTION 1 SUMMARY AND RESULTS Passive solar and energy conservation have not been economically evaluated in detail and they are, therefore, not listed in Table 1.1. Numerous past studies have shown the value of conservation and passive solar heating. An approximate fifteen percent reduction in fossil fuel requirements due to the implementation of passive solar heating and energy conservation measures has been built into the village Heating Requirement Forecast Tables listed in Section 4. It is assumed that these two methods of reducing usage will be implemented in the village. 2. Environmental and Technical Results of the environmental and technical evaluations are listed in Table 1.2. These results indicate the overall environmental and technical ranking of energy plans selected for detail study for the village of Stony River in order of preference to be: iL) diesel electric plus waste heat 2) diesel plus binary cycle generation with waste heat 2s APA34*%C5 9r1 APA 28P1 . EVALUATION MATRIX Diesel + Diesel + Diesel + Waste Heat Table 1.2 Diesel Local Hydro Binary Generation Supplemental Electric w/wo Electric Coal and/or Wood Wind Factor + Waste Heat Heat With Waste Heat Generation (A) Economic (Present Worth) B i (5 = (B) Environmental (1) Community Preference 9 = 4 = (2) Infrastructure 3 = 5 = (3) Timing x S 7 = (4) Air Quality 4 - 5 = (5) Water Quality 2 7 4 = (6) Fish and Wildlife 2 - 4 - (7) Land Use 2 c 4 = (8) Terrestrial Impacts =2 a 4A a TOTAL 25 = 37 = Environmental Ranking 1 S 4 = (C) Technical (1) Safety 2 - 2 = (2) Reliability 2 - 2 7 (3) Availability 2 a _8 a TOTAL 5 i 12 : TECHNICAL RANKING 1 ce 2 = OVERALL RANKING B-1 - C-2 _ SECTION 2 RECOMMENDATIONS APA34*C6 SECTION 2 RECOMMENDATIONS A. GENERAL Analysis of the 20-year economic, technical and environmental evaluations indicate the two most promising energy plans for the village of Stony River in order of preference to be: 1) Continued use of diesel generation supplemented with waste heat recovery, 2) diesel plus binary cycle generation supplemented with waste heat recovery. B. RECOMMENDED PLAN - Diesel Generation Supplemented with Waste Heat Recovery. The 20-year economic, technical and environmental evaluation indicate that diesel generation with waste heat recovery will provide the most satisfactory method of providing electric energy for the village of Stony River. It is recommended, therefore, that a study be conducted to determine the feasibility of utilizing waste heat in the village of Stony River. Such a study should include a definitive review of the following items: A) availability of waste heat 2) transportation of waste heat 3) end use of waste heat C. FIRST ALTERNATIVE PLAN - Diesel Plus Binary Cycle Generation Supple- mented With Waste Heat Recovery. The first alternative plan, as listed above, is diesel plus binary cycle generation with waste heat recovery. This plan averages approximately 33 percent greater costs than the recommended plan (20-year economic evalu- ation). Because the uncertainties in the costs associated with this alternative, such as the cost of wood fuel, equipment cost, etc., which 2a APA34*C7 SECTION 2 RECOMMENDATIONS can not at present be as precisely determined as for the recommended plan, it is conceivable that this alternative could be cost competitive with the alternative plan (ij.e., diesel generation plus waste heat recovery). Because binary cycle generation is viewed as one of the few potentially viable energy alternatives, suitable for future use in remote Alaska villages such as Stony River, it is recommended that the feasibility of binary cycle generation in Alaska be further investigated in regard to: 1) Equipment availability 2) Technical feasibility 3) Economic aspects 4) Environmental aspects 5) Constraints Binary cycle generation equipment in unit sizes suitable for village appli- cation is, however, not expected to be available until the late 1980's. D. COSTS FOR FURTHER STUDY Approximate costs for determining of feasibility of the two most attractive energy resources for the village of Stony River are: e Waste heat recovery - approximately $2500 e Binary cycle generation - approximately $2,000,000 which would include the cost of constructing and operating a demonstration plant in Alaska. E. CONSERVATION MEASURES For the village to stabilize and hopefully reduce the local cost of energy immediate short term conservation measures could provide the most rapid results. These conservation measures, which include added insulation, double glazing or solar film, arctic entrances, weather stripping, etc., can reduce current non-transportation fuel use on the order of 15 percent over the 20-year period of this study. one, SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE APA34*C9 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE A. INTRODUCTION To establish a base and understanding of energy use in the village, an energy balance has been compiled for the year 1979. Input energy forms are diesel, wood, propane, blazo, gasoline, and aviation gasoline. Energy used in the village has been listed both by end use category (i.e., heating, transportation, and quantities used for electrical generation) and by consumer category to include residential, small commercial, public buildings, and large users (school), in the following table (Table numbered as in original report). To provide background data, information related to village history, demographic and economic conditions plus information regarding village government, transportation, power and heating facilities is included. a. GENERAL BACKGROUND INFORMATION History: The village of Stony River is located approxi- mately 100 miles east of Aniak on the north bank of the Kuskokwim River 1.9 miles north of its confluence with Stony River. The village began in 1930 as a trading post and river boat landing used to supply mining operations to the north. These facilities were used primarily by Eskimos and Indians who lived nearby. It was not until the early 1960's that local Eskimos and Indians built cabins near the store and established year-round residency in the village. Pursuant to the Alaska Native Claims Settlement Act of 1971, the Stony River Village Corporation was entitled 3-1 APA34*C10 APA34*C11 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE to select 69,120 acres of Federal land. When the village corporation merged with 9 other Middle Kuskokwim Village Corporations, this entitlement passed to TKC for consoli- dated ownership and management. Calista Corporation is the regional corporation. Population: First recorded in the 1960 U.S. census, the population of Stony River was listed at 75 residents. The 1970 census reported 74 residents, 82% of which are Natives. A local count estimated the population of Stony River was 67 people in 1979. For 1979, the average number of members per household was 5.6 persons. Economy: Stony River's economy is heavily dependent on subsistence activities. Residents hunt moose, caribou, bear, waterfowl and small game. The fishing catch includes salmon and numerous other species of fresh-water fish. In the fall, berries are harvested by the residents. Most cash income comes from public employment programs. Seasonal work is available through the BLM summer fire- fighting program. The regional school district retains three full-time employees. Some additional income is derived from government assistance programs. Income is also derived from trapping. Government: Stony River is not incorporated as a muni- cipality under State law and there is no organized borough in the area. Stony River's Native population is represented by a 5-member traditional council. Transportation: Stony River's location along the Kuskokwim River affords easy access by boat in the summer months. 3=2 APA34*C12 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE Barge lines deliver fuel and bulk supplies to Stony River during the summer months via the Kuskokwim River. A gravel airstrip accommodates air traffic. Passenger, mail and small cargo items arrive primarily by air. During the winter months when the river is frozen, snow- machines provide the predominate mode of transportation. There are no roads connecting Stony River to other villages within the region. ENERGY BALANCE (1979) Approximately 62.5 percent of the energy requirements for the village are for heating. Transportation requirements are only 12.1 percent of the total, and electric generation accounts for the remaining 25.4 percent of energy usage in the village. Graph 3.11 illustrates by consumer category the types and percentages of energy forms used in the village. Table 3.11 tabularizes this data in additional detail. EXISTING POWER AND HEATING FACILITIES Electric Power: No centralized power generation facility exists in Stony River. Village electrification is scheduled for the summer of 1981. The school district maintains and operates two 50-kW diesel generators which supply the electrical energy needs of the school and certain public buildings. Heating: Residential and small commercial consumer heating requirements are satisfied almost entirely with wood. The average annual residential usage of wood and 3-3 APA34*C13 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE fuel oi] is 8 cords and 75 gallons, respectively. The community hall and clinic are heated with fuel oi] as are the school facilities. Fuel Storage: Diesel, bulk fuel oi] storage capacity in the community (school + village) is 28,000 gallons (reference 27). GRAPH 3.11 1979 ENERGY BALANCE STONY RIVER EFFICIENCIES ASSUMED: LEGEND _ HEATING — 75% ) — RESIDENTIAL TRANSPORTATION — 25% (ly — SMALL COMMERCIAL ELECTRICAL GENERATION — 25% [__] — PUBLIC BUILDINGS (GN) — LARGE USERS (SCHOOL) () — «WASTE HEAT TOTAL ENERGY (100%) 2.2% HEATING (62.5%) BLAZO. — 1.7% PROPANE— 0.3% WOOD — 23.6% DIESEL — 36.9% TOTAL — 62.5% TRANSPORTATION (12.1%) —— GASOLINE + AV GAS 12.1% ELECTRICAL GENERATION (25.4%) | | | | | | | | | | 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 BTU x 10° | 10,000 9-€ apa28: a6 ENERGY BALANCE - 1979 STONY RIVER Table 3.11 CONSUMER ENERGY FORM CONSUMED HEATING TRANSPORTATION ELECTRICAL DIESEL wooD PROPANE BLAZO GASOLINE AV GAL OIESEL TOTAL GAL CORDS POUNDS GAL GAL GAL GAL 10° Btu TYPE NO. 10® Btu 10® Btu 10® Btu 10® Btu 10® Btu 10® Btu 10® Btu % of Total Residential 900 96 = 900 5,400 1,200 7 2,708 124 1,632 114 686 152 39.2 Smal] Commercial 1 1,100 = Ss = = = = 152 152 2.12 Public Buildings 2 1,650 - - = = = 2,400 559 228 331 8.1 Large User (school) 1 14,800 = 1,200 = 7 - 10,300 3,486 2,042 23 1,421 50.5 Total 18,450 96 1,200 900 5,400 1,200 12,700 6,905 2,546 1,632 23 114 686 152 1,752 % of Total Btu 36.9 23.6 0.3 1.7 9.9 2n2 25.4 100 Waste Heat 10° Btu 637 408 _6 _29 515 114 1,314 3,023 % of Total 9.2 5.9 0.1 0.4 7.5 1.7 19.0 43.8 Assumed Efficiency: Heating - 75% Transportation - 25% Electric Generation - 25% SECTION 4 ENERGY REQUIREMENTS FORECAST APA34*C15 SECTION 4 ENERGY REQUIREMENTS FORECAST INTRODUCTION The following paragraphs and tables outline the planned capital projects, economic activities forecast, and energy end use forecasts for the village of Stony River.? 1 Tables numbered as in original report. 4-1 APA34*C16 APA 22-A:K1 SECTION 4 ENERGY REQUIREMENTS FORECAST 1l. Stony River (a) Planned Capital Projects and Economic Activity Forecast Planned Capital Projects: Scheduled developments - School classroom addition ‘ Electrification Airport improvements Potential developments - Timber harvest Peat harvest Farewell coal field 0i1 and gas exploration Economic Activity Forecast: Stony River could benefit from timber harvest, peat harvest, development of the Farewell coal field and possible oi] and gas exploration in areas along the Kuskokwim. Major developments of these activities are not expected, however, until the late 1980's or early 1990's. No immediate increase in economic activity is expected, however, in the near future. (b) Population Forecast - Stony River The population forecast is shown in the following Table 4.11 Table 4.11 Year 1970 1979 1982 1985 1990 2000 Population 74 67 68 70 74 82 # Residences - 12 12 13) 15 21 # Small commercial - 1 i 1 2 # Public users - 2 2 2 2 3 # Large users - 1 1 1 1 Population growth rate - 1% 4-2 q) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) apa22: a6 End Use Forecast The end uses of energy are shown in the following Tables 4. STONY RIVER ELECTRIC POWER REQUIREMENTS? 4. 1c. Table 4.1lla 1979 Population 67 Number of residential consumers - Average kWh/mo/consumer - MWh/year residential consumers (2) x (1) x 12 + 1000 7 Number of smal] commer- cial consumers = Average kWh/mo/consumer - MWh/year small commer- cial consumer (4) x (5) x 12 + 1000 - Number of public con- sumers + 2 Average kWh/mo/consumer 850 MWh/year public consumer (7) x (8) x 12 + 1000 20.4 Large (LP) consumer 1 (school) Average kWh/mo/LP 7,300 consumer? MWh/year LP's (10) x (11) x 12 + 1000 87.6 System MWh/year (3)+(6)+(9)+(12) 108.0 System load factor 0.6 System demand kW (13)+8760+(14)x1000 21 Electrification scheduled for summer 1981. School at 1% growth rate. Addition of new school classroom. 4-3 1982 68 12 133 19.2 848 10.2 970 23.3 9,400 T1257 165.4 0.45 42 1985 70 13 160 25.0 968 11.6 1,107 26.6 9,686 116.2 179.4 0.45 46 1990 74 15 220 39.6 1,205 14.5 1,379 33.1 10,180 12250 209.3 0.45 53 lla, 4.11b, 2000 82 21 415 104.6 1,872 44.9 2,142 — didn, 11,245 135.0 361.6 0.50 83 apa22:c6 Table 4.11b STONY RIVER HEATING REQUIREMENTS! RESIDENTIAL CONSUMERS 1979 1982 1985 1990 2000 (1) Population 67 68 70 74 82 (2) Number of resi- dential users 12 12 13 15 21 (3) Diesel - Average gal/mo/residence (6)+(2)+12 6 6 6 6 5 (4) Propane - Average lbs/mo/res idence (7)+(2)+12 A 5 10 19 35 (5) Wood - Average cords/mo/residence . (8)+(2)+12 0.67 0.67 0.67 0.63 0.58 (6) Diesel Gals 900 900 975 1,070 1,360 . Btu x 106 124 124 135 148 188 (7) Propane _Lbs 700 1,580 3,470 8,810 Btu x 105 14 31 68 172 (8) Wood Cords 96 96 ___104 114 145 Btu x 10° 1,632 1,632 1,768 1,938 2,465 (9) Total Btu x 106 (6)+(7)+(8) 1,756 13770 1,933 2,153 2,824 (10) Annual per capita consumption Btu x 106 (9)+(1) 26.2 26.0 27.6 29.1 34.4 z Assumes a one percent per year decrease in fossil fuel requirements beginning in 1986 due to implementation of passive solar heating and technical improve- ments in both building and heating equipment. 4-4 (11) (12) (13) (14) (15) (16) (17) (18) (19) apa22-A: R10 Table 4.1lc Smal1- Commercial user Diesel Gals/Btu x 10° Public Buildings user Diesel Gals Btu x 105 Large users (school) Diesel equivalent (diesel + wood) Gals Btu x 10° Propane __1bs Btu x 10° Subtotal. Btu x 106 (16)+(17) Total Btu x 106 (9)+(12)+(14)+(18 STONY RIVER HEATING REQUIREMENTS? OTHER CONSUMERS 1979 2065 ) 4, 201 1982 1985 1 al 1100 1100 152 152 2 2 1650 1650 228 228 aL 1 19,0572 19,057 2,629 2,629 1200 1200 23 23 2652 2652 4,802 4,965 1990 2000 Zu 2 1046 1420 144 196 2 3 1569 1891 216 261 a al 8,123 16,408 2,501 2,264 1141 1033 22 20 2523 2284 5,036 5,565 Assumes a one percent per year decrease in fossil fuel requirements begin- ning in 1986 due to implementation of passive solar heating and technical improvements in both building design and heating equipment. New classroom addi tion. Oo SECTION 5 RESOURCE AND TECHNOLOGY ASSESSMENT APA34*C17 SECTION 5 RESOURCE AND RECHNOLOGY ASSESSMENT A. ENERGY RESOURCE ASSESSMENT The energy resources which are determined to be available for the village of Stony River are summarized in the following table. Information concerning approximate quantity, quality, availability, cost, source of data and important comments is included. The energy resources specif- ically addressed include diesel generation, wind, hydroelectric potential, waste heat utilization, timber and coal. While passive solar heating and energy conservation are not specifically addressed in the table, it is assumed these two energy conservation measures will be implemented in the village.- Energy resources which are not available for use in Stony River and are therefore not addressed include geothermal, peat, solid waste, oil and gas and tidal power. Ss) APA34*C18 as APA22-A S10 Table 5.11 ENERGY RESOURCE Diesel fuel Wood fuel Coal fuel Waste Heat! Recovery Hydroelectric Potential Wind potential LOCATION Major supplier Bethel Middle Kuskokwim Healy, Alaska N/A ENERGY RESOURCE ASSESSMENT QUANTITY/AVAILABILITY 167x10% cu ft late 1980's Late 1980"s 30% of fuel used for electrical generation; upon installation of new power plant. N/A ' Assumes $1.47/gal diesel fuel cost 0.45 load factor. < > saving per million Btu recovered. STONY RIVER QUALITY #2 diesel 138,000 Btu/gal 14.6x10° Btu/cord 8500 Btu/Ib 17x10® Btu/ton Recoverable heat 41,400 Btu/gal diesel equivalent N/A 5.7 mph average annual wind speed. SOURCE OF cost DATA $1.47/gal United $10.66/10® Btu Transportation Bethel. $92/cord Appendix G $6.30/10° Btu $110/ton Appendix H $6.47/10° Btu $450/kW installed Appendix D <$5. 25/10 Btu> diesel fuel displaced N/A Reference #38 S Regional Profiles COMMENTS Delivered cost at village Delivered cost at village. Delivered cost at village. -Cost assume heat delivery within 100 ft radius of plant. Availability varies with generator loading. Maintenance at $11/kW/yr. Average annual wind speed insufficient for wind generation. SECTION 6 ENERGY PLANS APA34*C19 SECTION 6 ENERGY PLANS A. INTRODUCTION The approach to the energy plans formulated for the village of Stony River is explained in this section. Each plan is formulated to meet the forecasted electrical energy requirements of the village plus addi- tional related requirements, such as space heating, where appropriate. A base case plan using diesel generation is formulated for the village. This plan is used as the "control case" to determine the advantage or disadvantage of other alternatives as compared to diesel generation. Future village diesel generation additions assume that the local school, which has sufficient installed generation capacity, will provide its own back-up capability. The school will, however, rely on the central- ized village power plant for their primary supply of electrical power and energy. A wood-fired binary cycle generation option is presented for the village of Stony River. It is assumed the wood required for fuel would be supplied from timber harvested along the Kuskokwim River and its tributaries. Diesel fuel oil-fired binary cycle generation is also possible, but provides no significant cost or technical advantage over diesel engine powered generation. Fuel oil-fired binary cycle generation is, therefore, not included in the formulated energy plan for the village. A waste heat capture analysis is included with all options that use fossil fuels for electrical generation (i.e., diesel generation employing engine jacket water cooling, and binary cycle generation). 6-1 APA34*C20 APA 32/A19 SECTION 6 ENERGY PLANS Base Case Plan 1) 2) 3) Plan components - diesel and waste heat recovery Timing of system additions - Diesel - 1981 - 60 + 75 kW Waste heat equipment - 1983 - 75 kW Plan description - This plan assumes the continued use of diesel driven generators throughout the study and the implementation of waste heat recovery. Alternative Plan A 1) 2) 3) Plan components - diesel and binary cycle generation using wood fuel and waste heat recovery Timing of additions - Diesel - 1981 - 60 + 75 kW Binary cycle - 1989 - 100 kw Waste heat equipment - 1983 - 75 kW, 1989 - 100 kw Plan description - This plan assumes construction of wood-fired binary cycle generation facilities in the late 1980's as a replacement for diesel genera- tion and the implementation of waste heat recovery. 6-2 APPENDIX A DESCRIPTION OF SELECTED TECHNOLOGIES APA34*C21 A.1 DIESEL a. General Description 1) 2) APA*32C35 Thermodynamic and engineering processes involved In the diesel engine, air is compressed in a cylinder to a high pressure. Fuel oi] is injected into the compressed air, which is at a temperature above the fuel ignition point, and the fuel burns, converting thermal energy to mechanical energy by driving a piston. Pistons drive a shaft which in turn drives the generator. Current and future availability Diesel engines driving electrical generators are one of the most efficient simple cycle converters of chemical energy (fuel) to electrical energy. Although the diesel cycle in theory will burn any combustible matter, the practical fact of the matter is that these engines burn only high grade liquid petroleum.or gas, except for multi-thousand horsepower engines which can burn heated residual oi]. Diesel generating units are usually built as an integral whole and mounted on skids for installation at their place of use. A-1 A.2 BINARY CYCLE FOR ELECTRICAL GENERATION a. General Description 1) 2) APA*32C36 Thermodynamic and engineering processes involved In the binary conversion process, a heated primary fluid of insufficient quality for direct use in electrical production passes through a heat exchanger to transfer heat to a working fluid. The working fluid has a lower boiling point than water and is vaporized in the heat exchanger. The vaporized working fluid then expands through a turbine or cylinder piston arrange- ment is condensed, and returns to the heat exchanger. The primary fluid is returned to its heat source following heat exchange. Current and future availability Current commercial availability is restricted to unit sizes in excess of village power requirements as determined in this study. Binary cycle generation equipment in unit sizes suit- able for village application is not expected to be available> until the late 1980's. A-2 A.3 HYDROELECTRIC GENERATION a. General Description APA*32C37 Thermodynamic and engineering processes involved In the hydroelectric power development, flowing water is directed into a hydraulic turbine where the energy in the water is used to turn a shaft, which in turn drives a gener- ator. In their action, turbines involve a continuous trans- formation of the potential and/or kinetic energy of the water into usable mechanical energy at the shaft. Water stored at rest at an elevation above the level of the turbine (head) possesses potential energy; when flowing, the water possesses kinetic energy as a function of its velocity. The return of the used water to the higher elevation necessary for funct- joning of the hydroelectric machinery is powered by the sun to complete the cycle - a direct, natural process using solar energy. The ability to store water at a useful elevation makes this energy supply predictable and dependable. Current and future availability Hydroelectric developments in'the United States, as of January 1978, totaled 59 million kilowatts, producing an estimated average annual output of 276 billion kilowatt hours according to the U.S. Department of Energy (DOE). Hydropower provides about 10% of Alaska's electric energy needs. Developments range in size from over a million kilowatts down to just a few kilowatts of installed capacity. Hydropower is a time proven method of generation that offers unique advantages. Fuel cost, a major contributor to thermal plant operating costs, is eliminated. A-3 A.4 WIND ENERGY CONVERSION SYSTEMS (WECS) a. General Description 1) 2) APA*32C38 Thermodynamic and engineering processes involved The thermodynamic process involved stems from the sun, the primary energy source which produces the wind. This wind energy cannot be stored, is intermittent, somewhat unpredict- able and thereby undependable. The process then relies on wind flow over an air foil assembly to create differential pressures along the air foil. This differential pressure results in rotation of the assembly around a fixed axis to which it is attached. Power from the wind is transmitted through the connection shaft and accompanying gear box to an electrical generator. Three types of generators are presently in use with wind energy systems. These are the DC generator, the AC induction generator and the AC synchronous generator. Of the three types, the AC induction generator is the most widely used because of its simplicity and low cost. An induction generator is not a stand- alone generator and must be connected to an external power system of relatively constant frequency and voltage to operate properly. Current and future availability Availability of the wind at useful velocities require long term records to estimate the potential energy. Lesser records provide less credible estimates. Availability of WECS machinery in small size units in the 1.5 kw to 20 kW range is good. Large units in the 100-200 kW range are currently undergoing tests in both the government and private sector and should be available in the near future. Demonstrations of multi-megawatt sizes are in process. A-4 A.5 DIESEL WASTE HEAT RECOVERY a. General Description 1) 2) APA*32C39 Thermodynamic and engineering processes involved The present use of fossil fuels (coal, gas, oi]1) in Alaska (as elsewhere) to produce more useful forms of energy (heat, electricity, motive power) is less than 100 percent efficient. For example, if a machine burns a certain quantity of fossil fuel and produces useful output (shaft horsepower, electrical energy, steam, useful hot water or air for space heating) equivalent to 30% of the fuel burned, the energy represented by the remaining 70% of the fuel will appear as unused or "waste" heat. Such heat most often appears as hot exhaust gas, tepid to warm water (65°F-180°F), hot air from cooling radiators, or direct radiation from the machine. Diesel waste heat can be recovered from engine cooling water and exhaust, or either source separately. The waste heat is typically transferred to a water-glycol circulating system in Alaskan applications. The heated circulating.fluid can be used for space, water, or process heating where temperatures of the waste hear are suitable. Current and future availability Recovery of diesel waste heat in Alaska is growing as a result of sharp increases in diesel fuel cost. Recovery of jacket water heat only is most common in Alaska. Diesel waste heat availability is directly related to the location and operating cycles of the engine installations. A-5 A.6 PASSIVE SOLAR HEATING a. General Description Passive solar heating makes use of solar energy (sunlight) through energy efficient design (i.e. south facing windows, shutters, added insulation) but without the aid of any mechanical or electrical inputs. Space heating is the most common application of passive solar heating. Because such solar heating is available only when the sun shines its availability is intermittent (day-night cycles) and variable (winter-summer-cloudy-clear). A-6 APA*32C40 A.7 CONSERVATION a. General Description 1) 2) APA*32C41 Thermodynamic and engineering processes involved Conservation measures considered here are mainly classified as "passive". Passive measures are intended to conserve energy with- out any further electrical, thermal, or mechanical energy input. Typical passive measures are insulation, double glazing or solar film, arctic entrances and weather stripping. Energy conservation characteristics of some passive measures degrade with time, which must be considered in the overall evaluation of their effectiveness for an intended life cycle. Other conservation measures includes improvement in efficiency of utilization devices (such as motors) and "doing without" energy by disciplines (turning off lights, turning down thermostats). Current and future availability Materials and schemes to implement passive measures are commer- cially available and increasing in use all over the United States due to the rapidly escalating cost of energy.