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HomeMy WebLinkAboutAkhiok Reconnaissance Study Of Energy Requirements & Alternatives-Akhiok 19817491440 WOUS JAOWAY LON OC ASVATd S3Id09 AYWYEIT ALIMOHLAY YAMOd WISW IY = Summary Reconnaisance Study of Energy Requirements & Alternatives for . Akhiok Lf te Prepared For July 1981 Alaska Power Authority CH2M&#HILL ALASKA POWER AUTHORITY K14238 an MM PREFACE This summary contains the results of a study evaluating energy requirements and alternative electricity sources for the community of Akhiok on Kodiak Island. The study was performed as part of a larger study that included four communities on Kodiak Island and two communities on or near the Alaska Peninsula. This study is described in a report titled Reconnaissance Study of Energy Requirements and Alternatives for Akhiok, King Cove, Larsen Bay, Old Harbor, Ouzinkie, Sand Point, issued in June 1981. It was author- ized by the State of Alaska, Department of Commerce and Economic Development, Alaska Power Authority, in a contract with CH2M HILL signed October 9, 1980. iii aa MM RECOMMENDATIONS Akhiok is a community of 100 located on southwest Kodiak Island. The village has grown only slightly in recent years. Little additional economic activity is expected in future years and, as a result, population is expected to remain relatively stable. The present source of electricity is a recently installed, village-owned, 55-kilowatt (kW) diesel engine generator. The school generates its own electricity from two 25-kW diesel units. The current peak electricity requirements for both the village and school are approxi- mately 65 kW and are expected to grow to 80 kW by the year 2000. The least expensive source of electricity appears to be con- tinued central diesel generation. To meet both village and school electricity demands a new 80-kW diesel generator should be installed. The existing unit would then be used for standby generation only. The new school, scheduled for completion in 1981, could be served by the village's central electrical system. Because of the relatively small use of electricity by the community, the proposed Kempff Bay Creek hydropower project, which would be located approximately 2 miles west of Akhiok, appears to be an uneconomical generation project. Initial investment requirements for the project would be approxi- mately $2.0 million (January 1981 price levels). Waste heat recovery for school building heating is an energy source that was not considered in this study. However, waste heat recovery should be investigated further if the planned new school is constructed and served by its own new generat- ing plant or by a new village generating plant. Because the heat recovery system could easily be installed as the school is constructed, and because the new generating plant could be situated for low-cost heat recovery, this prospective source would probably be economical. The feasibility of waste heat recovery at the planned new school should be investigated. This would include devel- opment of preliminary layouts for equipment, assessment of the specific heating needs of the school, and preparation of cost estimates for the recovery equipment. The study would cost about $30,000. A more detailed investigation is needed to determine the feasibility of a weatherproofing and insulation program for primarily older housing stock. This investigation should include a more detailed description of existing insulation, the general condition of the housing stock, an assessment of heating requirements, and an assessment of both the costs and expected results of various conservation programs available to the community. Such an investigation would cost approximately $20,000. vi CONTENTS Preface Recommendations 1 Introduction 2 Existing and Projected Energy Requirements Existing Electrical Generation Plant Annual Energy Use Demographic and Economic Forecast Energy Requirements Forecast 3 Alternative Sources of Energy Small Hydroelectric Generation Induction Wind Generation Waste Heat Recovery From Central Diesel Engine Generators Heat Energy Conservation Peat Combustion for Electrical Generation Coal Combustion for Electrical Generation Solar Energy (Active Solar Heating and Electrical Generation) Single Wire Ground Return Electricity Transmission Preferred Sources of Electricity 4 Evaluation of Alternative Electricity Supply Plans Appendix. Economic Evaluation of Alternative Plans Environmental Evaluation of Alternative Plans Technical Evaluation of Alternative Plans Economic Evaluation of Providing Electric Heating Conclusions Detailed Descriptions of Preferred Electricity Sources vii UU WW Ww R onn 13 13 13 16 16 16 17 TABLES 1 Forecast of Annual Energy Requirements for Akhiok 6 2 Preliminary Evaluation of Alternative Energy Sources for Akhiok 12 3 Alternative Electricity Supply Plans for Akhiok 14 4 Evaluation of Alternative Electricity Supply Plans for Akhiok 15 FIGURES 1 Annual Energy Balance for Akhiok 4 se MM Chapter 1 MM INTRODUCTION Alternative sources of electricity for the community of Akhiok on Kodiak Island were identified and evaluated in the study summarized by this report. The sources recommended for further study could help the community reduce its dependence on expen- sive and often scarce diesel fuel for electrical generation. The purpose of the study was to recommend a series of activi- ties that will result in the identification of feasible alter- native sources of electricity. The sources studied include wind generation, peat and coal combustion for electrical generation, small hydroelectric generation, solar electric generation, and continued use of centralized or decentralized diesel generation. Waste heat recovery and the conservation of building heat were also evaluated. Establishment of the feasibility of a specific source was beyond the scope of the study. Information about these sources formed the basis for prep- aration of alternative plans to meet Akhiok's future demands for electricity. Electrical demands of the school were in- cluded in these plans. Each plan was assessed on the basis of its technical, economic, environmental, social, and insti- tutional characteristics. The assessments were performed in accordance with the procedures and assumptions established by the Alaska Power Authority. Further information about this study is contained in a report titled Reconnaissance Study of Energy Requirements and Alterna- tive for Akhiok, King Cove, Larsen Bay, Old Harbor, Ouzinkie, Sand Point, issued by the Alaska Power Authority in June 1981. Wm Chapter 2 MM EXISTING AND PROJECTED ENERGY REQUIREMENTS The CH2M HILL project team visited Akhiok during October 1980 and, through discussions and meetings with local resi- dents, obtained information on current living conditions, housing, household fuel consumption, employment, subsistence activities, and concerns about local resources. An inspec-— tion of the existing generation system was conducted to deter- mine the nature and condition of the plant. Additional infor- mation was obtained from published sources and interviews with personnel from the Kodiak Area Native Association and the Kodiak Island Borough. EXISTING ELECTRICAL GENERATION PLANT Akhiok has a new central generation plant and distribution system that provides electricity for community residents. At the time of the field investigation, the plant, consisting of one 55-kW generator, was in place but not yet operating because of a temporary lack of fuel. A separate generation plant, consisting of two 25-kW units, supplies electricity to the school. Several households continue to get their electricity from individual generators. The centralized system will operate for 6 to 10 hours per day. ANNUAL ENERGY USE There are no data on fuel consumption or generation in Akhiok. A local official estimated that the school consumes 10,000 gallons of fuel per year (or 180 barrels, at 55 gallons per barrel). Assuming that 85 percent of the consumption (155 barrels) was for generation, and using a conversion factor of 8 kWh per gallon, annual school generation was estimated to be 68,000 kWh. The remaining 15 percent, (30 barrels), was assumed to be for school heating. Fuel use for village generation was estimated at 390 barrels. End uses of elec- tricity include lighting and the operation of appliances such as refrigerators, freezers, televisions, washers, and dryers. Consumption of home heating fuel was estimated at 110 gal- lons per household per month in the summer and 220 gallons per household per month in the winter. Wood stoves have been provided to individuals residing in HUD houses. Wood fuel is primarily driftwood. End uses of heating fuel include heating, cooking, and water heating. Propane is occasionally used for cooking. Figure 1 summarizes energy information for Akhiok. IMPORTS MOTOR GAS DIESEL FUEL HOME HEATING FUEL 4000 GAL 541 bbl 1107 bbl END USE 500 x 10° Btu NON-RECOVERABLE GENERATION WASTE HEAT 1,472 x 10° Btu RECOVERABLE GENERATION WASTE HEAT 2000 x 10° Btu CITY GENERATION 170,000 Kwh ° SCHOOL GENERATION}— 68,000 Kwh Seah 8553 x 10° Btu 214 x 10° Btu SCHOOL HEATING FIGURE 1 ANNUAL ENERGY BALANCE FOR AKHIOK DEMOGRAPHIC AND ECONOMIC FORECAST Population is projected to increase at an average annual rate of 1.0 percent over the next 20 years. This will result in an increase of 22 people, or approximately seven house- holds. The number of houses is expected to increase approximately 1 percent annually during the next 20 years. It is expected that Akhiok will experience little growth in its housing stock beyond that required to accommodate increased popula- tion; therefore, the projected increase in the number of houses was derived from the projected population growth rate. It was assumed that seasonal residents will not contribute much to an increase in the total housing stock and that the average household size will remain stable. For the purpose of this analysis, it was assumed that oppor- tunities for Akhiok residents in the existing fisheries will remain about the same during the next 20 years; however, an experimental scallop muriculture program is under way at Akhiok. Program success could mean commercial scallop rearing near Akhiok within 5 years. The predominant land uses are expected to continue to be for subsistence activities. Akhiok is expected to remain a rela- tively stable village for the next 20 years. ENERGY REQUIREMENTS FORECAST Annual energy requirements for Akhiok were projected to the year 2000 (Table 1). Fuel use is projected to increase at the annual rate of 1 percent from 1980 through 2000. This growth rate is directly related to increases in population and housing; there was no basis for assuming any increase or decrease in average per capita consumption. Assuming no change in generating efficiency, both city and school genera- tion were projected to grow at the same rate. Over 20 years, this annual growth rate will result in a 22-percent increase in the demand for both fuel and electricity. Table 1 FORECAST OF ANNUAL ENERGY REQUIREMENTS FOR AKHIOK Fuel (bbl/yr)* 1980 1990 2000 Diesel (generation) 541 597 660 Home Heating Fuel (heating) 1,107 1,223 1,351 Total 1,648 1,820 27011: Generation (kWh/yr) Village 170,000 187,800 207,400 School 68,000 75,100 83,000 Total 238,000 262,900 290,400 Peak Electric Power Requirements (kW) Village 65 70 80 *One barrel equals 55 gallons. MM Chapter 3 MM ALTERNATIVE SOURCES OF ENERGY Alternative sources of electricity available to the community are identified and described in this chapter. The accuracy of these descriptions is consistent with the amount of data available from site investigations and research on the alter- natives. Continued use of centralized or decentralized diesel electric generation is included as an alternative. Near-term alternative heat energy sources are also identified and characterized. Specific alternative energy supply projects that were con- sidered include: Continued central diesel electric generation Kempff Bay Creek hydropower Induction wind generation Unnamed creek No. 1 hydropower Unnamed creek No. 2 hydropower Peat combustion for generation Coal combustion for generation Decentralized solar-electric generation Decentralized active solar heating Heat conservation Waste heat recovery at the existing City generating plant Single wire ground return electricity transmission oo0000000000 fo} General descriptions of these energy sources are provided below. SMALL HYDROELECTRIC GENERATION Hydroelectric energy is generated when flowing water spins a turbine, which drives a generator, producing electric energy. Hydroelectric generation is considered a renewable resource because the input energy source (falling water) is not de- pleted over time. Operating small-scale hydroelectric plants can also be relatively inexpensive. Use of the water is often free and hydroelectric plants cost little to operate and maintain. Also, the cost of the electricity produced by a hydroelectric plant remains relatively constant over time. Costs rise only when inflation increases operation and main- tenance costs, which constitute only a small portion of total plant costs. The major project cost is for initial construc- tion, which can be financed and paid for in equal periodic payments that will not increase with inflation. Small hydroelectric projects can be practical in many Alaska locations. The technology has been tested and proven in Alaska and throughout the world, and the skills needed to design and build plants are readily available. Rapid and efficient construction is possible, which minimizes costs. The environmental impacts of small hydroelectric plants are usually slight and can often be easily mitigated. Most of the small hydroelectric projects considered for this study would require a small diversion dam to create a small reser- voir, a penstock to transmit the water from the reservoir to the powerhouse, and a small powerhouse. INDUCTION WIND GENERATION Several kinds of wind-powered electric generators are com- mercially available, but they all share the same operating principle: the wind rotates the blades of a collector, which drives a generator to produce electricity. To attain the high speeds necessary for electrical generation, these wind machines must have airfoil blades similar to those of an airplane propeller. The axis of rotation for the collector can be either horizontal (like a farm windmill) or vertical (like an eggbeater). The electricity produced can either be alternating current (induction generation, which was con- sidered in this study, or synchronous generation) or direct current (which can be stored in small quantities in electric storage batteries). Because the wind is intermittent, a wind generator must be backed up by another generation source. In Alaska, this usually will be a conventional diesel engine generator. Wind generators also have a high initial cost and, because they are a relatively new source of electricity and are ex- posed to the elements, require more frequent maintenance than conventional generators. However, their environmental impact is minimal, except for some noise during operation. WASTE HEAT RECOVERY FROM CENTRAL DIESEL ENGINE GENERATORS The waste heat created by diesel engine generators can be captured and used for space heating. Ordinarily, two-thirds of the energy contained in the diesel fuel supplied to such a generator becomes waste heat that enters the environment via either the engine radiator or exhaust system. Almost all the radiated heat and about half the exhaust heat can be recovered. This means that up to half the energy content of diesel fuel can be recovered and converted into space heat for a building, if the building is within "economic proximity" to the generator (that is, if the cost of capturing, trans- porting, and using the heat is less than the cost of space heating by other means). The medium ordinarily used to recover and transport the waste heat is water. A water-to-water heat exchanger captures heat from the engine jacket water, and an air-to-water heat exchanger captures exhaust stack heat. The heat is trans- ferred to water that flows through a pipeline to a radiant space heating system. Another pipeline carries the used water back to the heat exchanger. One building or a build- ing complex can be heated in this manner. These systems can require a sizable initial investment, but they are usually very reliable and make use of a source of energy that would otherwise be wasted, so their fuel costs nothing. HEAT ENERGY CONSERVATION Conservation of heat used in buildings is possible through an increase in the buildings' thermal efficiency by addition of wall, window, ceiling, and floor insulation. Three types of buildings were considered in this study: school buildings, housing built before 1964, and housng built after 1964. No conservation options were assessed for school buildings because, in general, schools are of recent construction and are equipped with adequate heat conservation devices. In newer housing, existing building components such as roofs, walls, windows, and floors provide adequate thermal effi- ciency, although investigations of individual residences would probably result in specific recommendations for par- ticular dwellings. In older housing stock, existing struc- tural components do not provide adequate thermal efficiency. The major opportunity for heat conservation therefore lies in developing insulation programs for older housing stock. In newer housing that is presently heated with central forced air furnaces using gun-type oil burners, replacement with flame retention burners could reduce heating fuel consump- tion considerably. Overall, average conversion efficiency of the furnaces could be improved from about 73 percent to 85 percent with the use of these fuel-efficient burners. PEAT COMBUSTION FOR ELECTRICAL GENERATION Dried peat can be used as boiler fuel for steam turbine gener- ation or piston engine generation, much the same way wood can be. The peat must be cut, gathered, dried, and compressed into briquettes before it can be burned. Peat may be con- sidered a renewable energy resource, but the degree of renew- ability depends on the rate of use, regrowth rate, and size of the peat field dedicated as a fuel source. As with the use of wood, a considerable amount of machinery and labor is needed to harvest and process peat. The environmental costs can also be high. Harvesting can affect the land, water, and wildlife of the peat field, and peat combustion can cause air pollution. COAL COMBUSTION FOR ELECTRICAL GENERATION Coal can be burned in a boiler to produce steam, which can be used to drive a steam piston engine generator or a steam turbine generator. Coal is considered a nonrenewable resource that is relatively abundant but must usually be obtained from a distant supply source, much the same way diesel fuel must be obtained. Coal combustion technology is proven and reliable, but the burning of coal can have a significant effect on air quality. This can be mitigated through the use of pollution control equipment. SOLAR ENERGY (ACTIVE SOLAR HEATING AND ELECTRICAL GENERATION) Much of the earth's energy is derived directly from the sun through solar radiation. This radiation can be collected and used for space heating or to produce electricity. Both systems were considered in this study. A solar space heating system typically consists of a solar collection device and a fluid to transfer heat from the col- lector to a space heating system in a building. The system can also include a means for storing the heat when the demand for space heating is low. A system to produce electric energy typically consists of an array of photovoltaic cells and a set of batteries that store the electric energy produced by the cells. The photovoltaic cells produce direct current. If alternating current is needed, as is usually the case for a house, an inverter is required. Additional electrical control systems are used to regulate the system's operation. Solar heating and photovoltaic systems can be designed for use in Alaska, but they are ordinarily quite expensive. They require a very large initial investment and often more maintenance than alternative energy supply resources. The systems also require some form of backup system that will supply a user's needs during those times when demand is greater than the solar system can supply. SINGLE WIRE GROUND RETURN ELECTRICITY TRANSMISSION Single wire ground return (SWGR) electricity transmission operates in single phase and consists of a single overhead line. The earth acts as the second or return wire. A-frame 10 pole construction eliminates hole augering and the associated problems of pole jacketing in permafrost. In addition, local timber can be used for the poles. Single wire ground return transmission technology is relatively new, but it has been used successfully between the villages of Bethel and Napakiak, Alaska. PREFERRED SOURCES OF ELECTRICITY The alternative sources of energy identified at the beginning of this chapter were each evaluated on the basis of economic, environmental, and reliability and safety considerations, and conformance with community energy-source preferences. Out of this evaluation, summarized in Table 2, three prefer- red or best alternatives were selected for further analysis. These are described in detail in the appendix and considered further as part of the alternative electricity supply plans described in Chapter 4. i1 Table 2 PRELIMINARY EVALUATION OF ALTERNATIVE ENERGY SOURCES FOR AKHIOK Preferred Energy Sources (selected for further analysis) Continued central diesel electric generation Kempff Bay Creek Hydropower Induction wind generation Other Energy Sources (not considered further) Unnamed creek No. 1 hydropower Unnamed creek No. 2 hydropower Peat combustion for generation Coal combustion for generation Decentralized solar-electric generation Decentralized active solar heating Heat energy conservation Waste heat recovery at existing city generating plant Note: project available (October 1980). 12 Important Characteristics No initial investment required No significant adverse environmental impacts High reliability Proven technology See note below Low operating cost and no fuel cost . No significant adverse environmental impacts Important Characteristics See note below See note below High initial investment requirement High operating cost High fuel cost Significant adverse environmental impacts Prohibitively high initial investment requirement Unproven technology Not an electricity generation resource and thus not considered further Not considered further because few of the houses have either a significant heating requirement or could conveniently be retrofitted for hot water heating. Kempff Bay Creek hydropower is lowest cost oe ased on Corps of Engineers data MM Chapter 4 MM EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY PLANS This chapter identifies and evaluates alternative electricity supply plans. The plans were developed using the preferred energy sources described in Chapter 3. Plans were developed to meet both peak electrical requirements and annual energy requirements. Continued use of existing diesel engine genera- tion is considered an alternative supply plan and is identi- fied as Plan A, Base Case. Supply plans to meet future space- heating requirements were not developed. Alternative supply plan descriptions are contained in Table 3, and plan evaluations are summarized in Table 4. ECONOMIC EVALUATION OF ALTERNATIVE PLANS Alternative electricity supply plans were evaluated on the basis of total plan costs for installation, operation, and fuel for both the next 20 and 50 years. Total plan costs are shown in Table 4 in the columns headed "Present Value of Plan Costs." In accordance with Alaska Power Authority guide- lines, the present value of plan costs is the sum of all costs (initial investment, operation and maintenance, and fuel) associated with a plan during the 20-or 50-year plan- ning period. To obtain the present value of these costs, plan costs in their year of expected occurrence were dis- counted back to January 1981 at 3 percent per year. The rate of general inflation was assumed to be zero percent per year, but diesel fuel prices were assumed to rise at an aver- age annual rate of 3.5 percent. This method of evaluation is fair to both the continued use of diesel generation and the alternative development of new generation sources that involve high initial costs and low operating costs, such as hydropower projects. The 3.5 per- cent annual rise in diesel fuel prices is significantly lower than the actual rise in these prices is expected to be, but the 3-percent amortization rate for high-initial-cost sources such as hydropower projects is also significantly lower than these rates are expected to be, so both types of sources receive equal treatment. ENVIRONMENTAL EVALUATION OF ALTERNATIVE PLANS Evaluations of the environmental impact(s) of alternative electricity supply plans are based on assessments of the following impacts: a3. vT Table 3 ALTERNATIVE ELECTRICITY SUPPLY PLANS FOR AKHIOK Plan Plan Description A Continue use of central diesel generation. (Base Case) Service new school (to be constructed in 1981) with village electric system. To meet load growth, add one 80-kW engine generator unit in 1981 ($400/kW); place existing 55-kW unit on standby. Replace 80-kW unit in 1997 ($400/kW). B Develop and operate Kempff Bay Creek hydropower plant. Service new school (to be constructed in 1981) with village electric system. Plan and license hydropower project in 1981 and 1982. Total costs are approximately $50,000 for 1981 and $100,000 for 1982. Install and construct hydropower plant 1983 and 1984. Plant available in January 1985. Backup generation from existing (55-kW) central diesel plant. Minimum diesel backup plant operating, maintenance, and fuel cost is $10,000 per year. c Develop and operate induction wind generation facility. Maximum wind generation contribution to village electric load will be 25 percent. Service new school (to be constructed 1981) with village electric system. Plan wind generation project in 1981 and 1982; cost is approximately $50,000 per year. Install and construct wind generation facility in 1983. Facility available in January 1984. Replace wind generation equipment in 1998 ($198,000). Remaining generation from central diesel electric plant. Diesel plant acquisition and replacement schedule same as Plan A. Note: All costs are based on January 1981 price levels. ST 20-Year Planning Period Present Value of Plan Table 4 EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY 50-Year Planning Period Present Value of Plan PLANS FOR AKHIOK Plan Plan Description Costs ($)* Costs ($)* Energy Performance Environmental Impacts Reliability/Safety A Continued central 0.93 million 1.95 million Sufficient to meet com No major impacts Highly reliable, minor (Base Case) diesel-electric munity (village and safety concerns generation school) electric require- ments B Kempff Bay Creek 1.73 million 2.70 million Sufficient to meet com- Potentially prohibitive Highly reliable, backup Hydropower project munity (village and environmental impacts. with central diesel gener- school) electric Field investigation re- ation. Some safety con- requirements vealed late summer pres- cerns regarding seismically ence of spawning pink induced dam structural salmon. Brown bears in- failure. habit entire drainage area. Salmon below dam- site could be adversely affected by streamflow fluctuations and silta- tion caused by project construction and opera- tion. c Induction wind genera- 1.32 million 2.37 million Sufficient to meet com- Minor adverse environmen- Questionable reliability tion (25%) with cen- tral diesel generation (758) munity (village and school) electric requirements tal impact. Some noise during operation. Noise can be mitigated by remote location siting. resulting from variations in wind availability. Backup with central diesel generation. Minor safety concerns with remote siting. “January 1981 costs. Community infrastructure and employment Other planned capital projects ° Air quality ° Water quality ° Fish and wildlife ° Land use ° Terrestrial ° ° Detailed estimates of the magnitude of an impact were not possible. However, major concerns are identified and in- cluded in the evaluations. Alternative energy systems were designed to be environmentally acceptable. In those in- stances where additional equipment was required to make a source acceptable, the costs of such equipment were included in cost estimates. Detailed descriptions of possible environ- mental impacts are contained in the appendix. TECHNICAL EVALUATION OF ALTERNATIVE PLANS Alternative electricity supply plans were formulated to result in generation systems of similar reliability and safety that would be capable of meeting the complete electricity needs of the community. Detailed descriptions of each alternative's reliability and safety are contained in the appendix. ECONOMIC EVALUATION OF PROVIDING ELECTRIC HEATING The Kempff Bay Creek hydropower project was assessed to deter- mine whether it could provide economical electricity for lighting, appliances, and other conventional uses, and for new electric heating systems. The assessment indicated that the Kempff Bay Creek hydropower project would not be an eco- nomical generation source even when excess electric energy available from the project (above that required to displace diesel engine electric generation) is used for electric heat- ing. Year 1990 estimated hydropower costs are approximately $96,000, but the estimated total cost of the energy that would be displaced is only $83,000. CONCLUSIONS Based on the information reported in Table 4, continued cen- tral diesel engine generation for both village and school use appears to be the least costly source of electricity. Continued diesel generation, when evaluated over both 20- and 50-year periods, will cost significantly less than develop- ment and operation of alternative generation sources. The present value of the 20-year cost for continued central diesel electric generation is $0.93 million. The present value of the next least expensive alternative is $1.32 million. In addition, continued central diesel electric generation is a reliable generation source (when adequate fuel supplies are available) and involves relatively few environmental or safety concerns. 16 MM Appendix MM DETAILED DESCRIPTIONS OF PREFERRED ELECTRICITY SOURCES 17 Resource/Village: Continued central diesel generation/Akhiok Energy Form: Electric energy General Description: Contirued central diesel electric generation Resource Location: Akhiok Renewable or Nonrenewable: Nonrenewable Resource Characteristics: Existing diesel generation plant consists of one 55-kW engine generator set. Energy Production: Estimated conversion efficiency is 10.5 kWh per gallon of fuel oil. Input Energy (fuel) Characteristics: NA Resource Reliability: Engine generator unit(s) highly reliable; questionable avail- ability of diesel fuel supply Resource Cost (January 1981 price levels): Construction and engineering ($/kW) 600 (additional units) Replacement cost ($/kW) 400 Operating and maintenance cost (¢/kWh) 2.6 Current fuel cost ($/gal.) 1.40 Maintenance Requirements: Periodic maintenance required. Minor overhaul required every 8,000 operating hours. Major overhaul required every 24,000 operating hours. Operating activity requirement is 1 hour per day for one operator/maintenance person. Resource Development Schedule: NA Environmental Impacts: No major impacts Institutional, Social, and Land-Use Considerations: No major considerations Health and Safety Impacts: No major considerations 19 Resource/Village: Energy Form: Electric energy Hydropower plant on Kempff Bay Creek/Akhiok General Description: A low concrete diversion dam diverts water from Kempff Bay Creek into a penstock that runs parallel to the creek to a powerhouse located near the mouth of the creek. An alternative could be a lake tap at the unnamed lake on the headwaters of the Kempff Bay Creek. However, the diversion is probably cheaper, and locating it downstream from the lake gives more drainage area and therefore a more dependable flow. 50 feet NGVD. Resource Location: west of Akhiok Renewable or Nonrenewable: Renewable Resource Characteristics: Dam Type Height (ft) Operation Spillway Type Capacity (cfs) Penstock Length (ft) Diameter (in) Powerhouse Type of machine Number of units Installed capacity (kW) Transmission Facilities Type Length (miles) Production: Installed capacity (kW) Average annual energy (kWh) Plant factor (%) Dependable capacity (kW) Annual energy, low-flow year (kWh) Annual energy, high-flow year (kWh) Input Energy (Fuel) Characteristics: Drainage area (sq. mi.) Average annual flow (cfs) Low flow (cfs) High flow (cfs), Total head (ft) Net head (ft) Maximum penstock flow (cfs) Powerhouse located so that tailwater elevation is about 0.5 mile upstream from mouth of Kempff Bay Creek, about 2 miles Concrete diversion 10 Run-of-river Concrete overflow 1,000 (500-year peak flow) 2,900 18 Reaction 1 137 Single wire, ground return 2 137 592,000 50 20 474,000 710,000 1.4 10.9 1.0 870 150 127 12.7 Resource Reliability: The project is located on a stream with a small drainage area, and it is sized to use most of the available flow. of the plant is subject to natural fluctuations in runoff. For this reason the output The project has no storage to carry over generation capability during dry periods. Resource Cost (January 1981 Construction and engineering ($) Unit cost ($/kW) Annual operating and maintenance ($) ice levels): 1,872,000 13,660 17,625 Maintenance Requirements: Periodic maintenance will be required to overhaul or replace worn-out or defective parts. The frequency should be minimal because the technology for hydropower projects has been developed and proved. Hydropower proj- ects of this size can be operated with very minimal manpower and/or can be operated by remote telecommunications. Useful operating lifetime is 30 to 50 years. Resource Development Schedule: available in January 1985 Environmental Impacts: spawning pink salmon. to the lake outlet. Installation and construction in 1983 and 1984, The field investigation revealed late summer presence of Salmon remains were found over the full length of the stream Brown bears inhabit the entire drainage area, and their active presence was evident from digs, tracks, and salmcn feeding remnants. Institutional, Social, and Land-Use Considerations: Possible land-use conflicts resulting from siting plant and transmission system. Health and Safety Impacts: No significant impacts 21 Resource/Village: Wind generation/Akhiok Energy Form: Electric energy General Description: Installation and operation of horizontal axis wind induction generator to provide approximately 10-kW average power output. System to consist of one wind generator rated for 25 kW maximum output, with support tower, control equipment, and transformation and transmission facilities to integrate into existing community electric distribution system. Wind power to be backed by diesel genera- tion to firm up power base and for system integrity and reliability. Approximate maximum wind generation contribution to total system electric load is 25 percent. Resource Location: In favorable location with respect to wind speed and direction, as close to the central electric distribution system as practical Renewable or Nonrenewable: Renewable Resource Characteristics: One 25-kW peak wind generation machine Energy Production: 25-kW peak output, 10.0-kW average output, 87,000-kWh-per-year electric energy output Input Energy (fuel) Characteristics: Average annual wind speed of approximately 17 mph. Wind speed and direction vary. Resource Reliability: Downtime for system due to lack of wind estimated at 20 to 25 percent. Maintenance activity downtime estimtes at 5 percent. Resource Cost (January 1981 price levels): Construction and engineering ($) 396,000 Unit cost ($/kW) 15,840 Annual operating and maintenance ($) 8,400 Maintenance Requirements: Average operating activity requirement is one person 1 day per month. Average maintenance activity requirement is one person 1 week per year per machine. Annual equipment replacement cost is $5,000 per machine. Approxi- mate useful lifetime is 15 years. Resource Development Schedule: Installation in 1983, available in January 1984 Environmental Impacts: Some noise emission during resource operation. Noise levels can be mitigated by strategic and remote location siting. Institutional, Social, and Land-Use Considerations: Possible land-use conflicts resulting from siting plant and transmission system. Health and Safety Impacts: No significant impacts 23