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HomeMy WebLinkAboutNicholai Reconnaissance Study of Energy Requirements & Alternatives 5-1981VIL-R 004 ALASKA POWER AUTHORITY Nikolai LIBRARY COPIES PLEASE DO NOT REMOVE FROM OFFICE! OF ENERGY REQUIREMENTS & ALTERNATIVES FOR PROPERTY © ae Alaska Power Auih ony 334 W. Sih Ave. Anchorage, Alaska 99600 INTERNATIONAL ENGINEERING COMPANY, INC. A MORRISON-KNUDSEN COMPANY ROBERT W. RETHERFORD ASSOCIATES DIVISION PPP Pri eer Pt WSs ee NIKOLAI 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 nor wn eH 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 1.1 2.1 3.1 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 Nikolai supplement represents a brief summary of the most pertinent facts and findings contained in the original report which relate to the village of Nikolai. 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 Nikolai 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. 1-1 APA32*L1 BARROW OCRay, Noatok River ° _— ' : o &- es Mountains : Yukon - Tonana Ploteou | FAIRBANKS Lote | wy Minchuming —“"***9 Rong, \ é 'Susiing R. piPPer Oairict | & iver : Mounier | a, 3 a moet a, & x J Glacier i J a ? _ ne) ETHEL < (ANCHORAGE \ 2 TiheWe a v Q C a at gt = é ZS_ »" ae xe 9p & of YAKUTAT Guilt of Aloske : g poy Bristos BO KODIAK pACIFIC OCEAN as os ‘ ne — ho 7 a FIGURE 1.1 1 BUCKLAND 2 HUGHES 3) KOYUKUK 4 RUSSIAN MISSION 5 SHELDON POINT 6 CHUATHBALUK 7 CROOKED CREEK 8 NIKOLAI 9 RED DEVIL 10 SLEETMUTE 11 STONY RIVER 12 TAKOTNA 13 TELIDA g UNEA| ¢ 4, WV 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 1. 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 Nikolai. 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 Nikolai. The diesel generation plus binary generation with waste heat energy plan averaged approximately 22 percent greater cost than the diesel generation plus waste heat recovery plan for Nikolai. APA32*L3 vol NIKOLAI 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 1841-210.0 2250-167.8 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 imptementation 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 Nikolai in order of preference to be: 1) diesel electric plus waste heat 2) diesel plus binary cycle generation with waste heat 1-5 APA32*L5 9-1 APA 28P1 Table 1.2 Factor (A) Econo! (B) Envir qQ) (2) (3) (4) (5) (6) (7) (8) Envir (C) Techn (1) (2) (3) mic (Present Worth) onmental Community Preference Infrastructure Timing Air Quality Water Quality Fish and Wildlife Land Use Terrestrial Impacts TOTAL onmental Ranking ical Safety ~ Reliability Availability TOTAL TECHNICAL RANKING OVERALL R ANKING . EVALUATION MATRIX Diesel + Diesel Local Hydro Electric w/wo Electric + Waste Heat Heat Diesel +. Diesel + Waste Heat Binary Generation Supplemental Coal and/or Wood Wind With Waste Heat Generation Inne NNR ee ww ' Np ao |p ez RR ONO 1 w ~N 1 leo wn i) 12 c-2 - SECTION 2 RECOMMENDATIONS APA32*L6 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 Nikolai 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 Nikolai. It is recommended, therefore, that a study be conducted to determine the feasibility of utilizing waste heat in the village of Nikolai. Such a study should include a definitive review of the following items: 1) 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 22 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 2-1 APA32*L7 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 (i.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 Nikolai, 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 Nikolai 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. I 2-2 APA32*L8 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE APA32*L9 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: Nikolai is located at the confluence of the South Fork of the Kuskokwim River and the Little Tonzona River about 46 miles east of McGrath. The Ingalik Indian village has been located at the present site since 1925. The village was previously located miles upstream of the South Fork of the Kuskokwim. Nikolai is contained within the Doyon Limited Corporation boundaries. Population: The population of Nikolai has fluctuated dramatically over the past decade. The 1970 census showed a population of 112. The population increased to a high of 152 in the mid-70's and subsequently decreased to 96 in 1980 (estimated by village council). Natives comprise all but a few percent of the population of Nikolai. In 1980, the average number of members per household in the village was 4.4 persons. 3-1 APA32*L10 APA32*L11 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE Economy: The economy of Nikolai is primarily dependent on subsistence activities. Employment is found in seasonal work during the summer. Permanent employment is limited to the clinic, the city, the school district, the store and a few government or government-related jobs. Other cash income in the community comes in the form of public assistance and from the sale of furs caught during the trapping season. Nikolai residents hunt beaver, muskrat, game birds, rabbit, moose and waterfowl. Most residents fish during the summer months for salmon and other fish species. In the fall families harvest numerous varieties of berries. Transportation: Nikolai's location on the Kuskokwim River allows delivery of fuel and bulk supplies by river barge. An airstrip adjacent to the village provides air access. Passengers, small cargo items and mail arrive primarily by air. Small boats provide inter-village transportation during the summer month. Snowmachines are the primary method of transportation during the winter after the river freezes. No roads connect Nikolai with surrounding communities. ENERGY BALANCE (1979) The heating requirements in the village of Nikolai account for approximately 58.3 percent of the energy consumed by the village, transportation needs are 13.7 percent and electric generation 28.0 percent. Graph 3.8 illustrates by consumer category the types. and percentages of energy forms used in the village. Table 3.8 tabu- larizes this data in additional detail. 3-2 APA32*L12 SECTION 3 EXISTING CONDITIONS AND ENERGY BALANCE EXISTING POWER AND HEATING FACILITIES Electric Power: The village of Nikolai maintains and operates a centralized electric generation facility. Generation capacity consists of a 25-kW, a 50-kW and a 15-kW diesel-generator set. The school district does not maintain a standby generation facility in Nikolai. The distribution system is overhead triplex construction operating at a voltage of 480 volts. Heating: Residential and commercial heating are primarily with wood fuel in individual wood stoves. Residential consumers average approximately 9 cords of wood per year for heating. Public buildings and the school heat mainly with fuel oi]. The school, however, has recently installed a wood-burning stove and will attempt to heat one classroom with wood. Fuel Storage: Diesel, bulk fuel oil storage capacity in the community (school + village) is estimated at 35,000 gallons (estimated during village visit). 3-3 GRAPH 3.8 1979 ENERGY BALANCE NIKOLAI EFFICIENCIES ASSUMED: LEGEND _ HEATING — 75% GN — RESIDENTIAL TRANSPORTATION — 25% ( — SMALL COMMERCIAL ELECTRICAL GENERATION — 25% (5 — PuBLic BUILDINGS (ER) —_ LARGE USERS (SCHOOL) ) — WASTE HEAT 4.2% TOTAL ENERGY (100%) ; HEATING (58.3%) BLAZO aoe PROPANE— 2.1% WOOD — 30.1% DIESEL — 26.1% TOTAL — 58.3% TRANSPORTATION (13.7%) ne GASOLINE + AV GAS 13.7% ELECTRICAL GENERATION (28.0%) | | | | | | | | | | | | | | | | | | | 0 2000 4000 6000 8000 10,000 12,000 14,000 16,000 18,000 BTU x 108 20,000 G-€ apa28: a8 ENERGY BALANCE - 1979 NIKOLAI Table 3.8 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 22 - 198 10,700 = 12,100 - 3,880 5,644 3,366 207 1,536 535 50.5 Small Commercial 2 1,100 - 7 - - - 2,280 467 152 315 4.2 Public Buildings 3 1,550 > - . 7 . 3,600 71 214 497 6.4 Large User (school) 1 18,460 - 1,200 7 - - 12,880 4,347 2,547 23 1,777 38.9 —— nh Total 28 21, 198 11,900 - 12,100 - (a 640 > - 5913 3,366 230 1,536 »124 11,16 % of Total Btu 26.1 30.1 2.1 - 13.7 - 28.0 100 Waste heat ci’ 10° Btu 728 842 _58 1,152 343 5,123 % of Total Btu 6.5 7.5 0.5 10.3 21.0 45.8 Assumed Efficiency: Heating - 75% Transportation - 25% Electric Generation 25% SECTION 4 ENERGY REQUIREMENTS FORECAST APA32*L14 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 Nikolai.? 1 Tables numbered as in original report. 4-1 APA32*L15 APA 22-A:H1 : SECTION 4 ENERGY REQUIREMENTS FORECAST 8. Nikolai (a) (b) Planned Capital Projects and Economic Activity Forecast Planned Capital Projects: Scheduled developments - Airport improvements Potential developments - Farewell coal field Timber harvest Economic Activity Forecast: The village of Nikolai could be directly affected by development of coal mining activities in the Farewell area of the Alaska Range through an increase in employ- ment opportunities in the area. Operation of such a venture, however, is not expected until the early 1990's. Indirect benefits would result from lowered energy costs in the village as the result of possible coal fired elec- tric generation. No substantial increase in economic activity is expected, however, in the near future. Population Forecast - Nikolai The population forecast is shown in the following Table 4.8 Population growth rate - 1% 4-2 Table 4.8 Year 1970 1979 1982 1985 1990 2000 Population 112 96 98 101 106 129 # Residences - 22 22 23 25 29 # Small commercial - 2 2 2 2 2 # Public users - 3 3 4 5 ’ # Large users - 1 1 1 1 1 apa22: a8 C. End Use Forecast The end uses of energy are shown in the following Tables 4.8a, 4.8b, and 4.8c. Table 4.8a NIKOLAI ELECTRIC POWER REQUIREMENTS?! 1979 1982 1985 1990 2000 Population 96 98 101 106 129 (1) Number of residential consumers 22 22 23 25 29 (2) Average kWh/mo/consumer 125 1 133 160 220 415 (3) MWh/year residential V consumers . (2) x (1) x 12 + 1000 33.0 35.1 44.2 66.0 144.4 (4) Number of small commer- cial consumers 2 2 2 3 3 (5) Average kWh/mo/consumer 810 848 968 1,204 1,872 J (6) MWh/year small commer- cial consumer sy (4) x (5) x 12 + 1000 19.4 20.4 23.2 43.3 67.4 (7) Number of public consumers 3 3 4 4 5 (8) Average kWh/mo/consumer 850 . 970 1,107 1,379 2,142 J (9) MWh/year public consumer (7) x (8) x 12 + 1000 30.6 34.9 53.1 66.2 128.5 (10) Large (LP) consumer 1 1 1 1 1 (school) (11) Average kWh/mo/LP 9,125 9,400 9,686 10,180 11,245 consumer? (12) MWh/year LP's (10) x (11) x 12 + 1000/109.5 112.8 116.3 122.2 135.0 (13) System MWh/year : (3)+(6)+(9)+(12) 192.5 203.2 236.8 297.7 475.3 (14) System load factor 0.45 0.45 0.45 0.45 0.50 (15) System demand kW (13)+8760+(14)x1000 49 52 60 76 109 1 Estimated from utility records 2 School at 1% growth rate 4-3 apa22:c8 Table 4.8b NIKOLAI HEATING REQUIREMENTS? RESIDENTIAL CONSUMERS 1979 1982 1985 1990 2000 (1) Population 96 98 101 106 129 (2) Number of resi- dential users 22 22 23 25 32 (3) Diesel - Average gal/mo/residence (6)+(2)+12 0 0 0 0 0 (4) Propane - Average Ibs/mo/residence (7)+(2)+12 41 41 41 39 35 (5) Wood - Average cords/mo/residence (8)+(2)+12 0.75 0.75 0.75 0.71 ~=- 0.65 (6) Diesel Gals 0 0 0 0 0 Btu x 10° : (7) Propane _ Lbs 10,700 10,700 11,200 11,580 13,522 Btu x 106 209 209 218 226 264 (8) Wood _ Cords 198 198 207 214 248 Btu x 105 3,366 3,366 3,519 3,638 4,216 (9) Total Btu x 106 (6)+(7)+(8) 3,575 3,575 3, 737 3,864 4,480 (10) Annual per capita consumption Btu x 106 (9)+(1) 37.2 36.5 37.0 36.5 . 34.7 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 design and heating equipment. 4-4 (11) (12) (13) (14) (15) (16) (17) (18) (19) apa22-A:R7 Table 4.8c NIKOLAI HEATING REQUIREMENTS OTHER CONSUMERS 1979 1982 1985 1990 2000 Smal] Commercial 2 2 2 3 3 user Diesel 1100 1100 1100 1569 1420 Gals/Btu x 106 152 152 152 216 196 Public Buildings user 3 3 4 4 5 Diesel Gals 1550 1650 2775 2639 3358 Btu x 10° 214 228 383 364 463 Large users 2 (school) 1 1 1 1 1 Diesel equivalent (diesel + wood) Gals 18,460 18,460 8,460 17,555 15,894 Btu x 10° 2,547 2,547 2,547 2,423 2,193 Propane __lbs 1200 1200 1200 1141 1033 Btu x 106 23 23 23 22 20 Subtotal Btu x 106 (16)+(17) 2570 2570 2570 2445 2213 Total Btu x 106 . (9)+(12)+(14)+(18) 6,511 6,525 6,842 6,889 7,352 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. 4-5 SECTION 5 RESOURCE AND TECHNOLOGY ASSESSMENT APA32*L16 SECTION 5 RESOURCE AND RECHNOLOGY ASSESSMENT A. ENERGY RESOURCE ASSESSMENT The energy resources which are determined to be available for the village of Nikolai 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 Nikolai and are therefore not addressed include geothermal, peat, solid waste, oil and gas and tidal power. 5-1 APA32*L18 2-g APA22-A S7 Table 5.8 ENERGY RESOURCE Diesel fuel Wood fuel Coal fuel Waste Heat! Recovery Hydroelectric potential Wind potential LOCATION Major supplier McGrath 10-mile radius Healy, Alaska N/A Villagers indicate insufficient wind in village for wind power. QUANTITY/AVAILABILITY 42.9x10® cu ft late 1980's Late 1980's 30% of fuel used electrical genera upon installation N/A ' Assumes $1.67/gal diesel fuel cost 0.45 load factor. < > saving per million Btu recovered. ENERGY RESOURCE ASSESSMENT NIKOLAI QUALITY #2 diesel 138,000 Btu/gal 14.6x10® Btu/cord 8500'Btu/1b 17x10® Btu/ton for Recoverable heat 41,400 Btu/gal diesel equivalent tion; N/A SOURCE OF cost DATA $1.67/gal Village $12.11/10° Btu Council $132/cord Appendix G $9.04/10° Btu $120/ton Appendix H $7.06/10° Btu $450/kW installed Appendix D <$6.73/10® Btu> diesel fuel displaced N/A Reference #38 No wind data available. 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. N/A SECTION 6 ’ ENERGY PLANS APA32*L17 SECTION 6 ENERGY PLANS A. INTRODUCTION The approach to the energy plans formulated for the village of Nikolai 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 Nikolai. It is assumed the wood required for fuel would be supplied from timber harvested within a 10-mile radius of the village. 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 APA32*L19 APA32*L20 SECTION 6 ENERGY PLANS Base Case Plan 1) 2) 3) Plan components - diesel and waste heat recovery Timing of system additions - Diesel - 1986 - 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 - 1986 - 75 kW Binary cycle - 1989 - 125 kW Waste heat equipment - 1983 - 75 kW, 1989 - 125 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 APA32*L21 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 diese? 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.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, oi1) 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.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. A-7 Alaska Power Authority 334 W. 5ih Ave, Anchorage, Alaska 99501