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HomeMy WebLinkAboutLarsen Bay Reconnaissance Study of Energy Requirements & Alternatives 7-1981(391440 WOUS JAOWSY LON OG JSW31d S41d09 AUVual ALIYOHLNY YSMOd WASWT Summary Reconnaisance Study of Energy Requirements & Alternatives for Larsen Bay Y sm Ms wie ml fi i Prepared For July 1981 Alaska Power Authority CH2M&EHILL ALASKA POWER AUTHORITY an MM OPREFACE This summary contains the results of a study evaluating energy requirements and alternative electricity sources for the com- munity of Larsen Bay 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 Pen- insulas This study is described in a report titled Reconnais- sance Study of Energy Requirements and Alternatives for Akhiok, King Cove, Larsen Bay, Old Harbor, Ouzinkie, Sand Point, issued in June 1981. It was authorized 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 an MM RECOMMENDATIONS Larsen Bay is a village on west-central Kodiak Island. It has a year-round population of about 120. Kodiak Island Sea- foods, Inc. (KISI), maintains a large processing plant in the harbor area. KISI operates only during the summer months and primarily employs transient workers. The village has grown in recent years; and as a result of continued economic activity, the availability of new housing, and a new village school, future growth is expected. The village electricity system consists of approximately 20 privately owned 5-kilowatt (kw) diesel engine generators. The village school is served by two 60-kW diesel generator units. Current peak electric requirements for the community and school are estimated to be 100 kW; these are expected to grow to 320 kW in the year 2000. The preferred alternative electricity supply system would consist of a standby central diesel generator, serving the entire village, and a hydropower plant at Humpy Creek. This would require the installation of a central electrical dis- tribution system for the village. The recommended standby plant would consist of one 120-kW diesel engine generator. Development and operation of a Humpy Creek hydropower plant appears to be lower in cost than continued decentralized diesel-electric generation or installation of a central diesel-electric plant. The Humpy Creek project would be 1 mile south of the village and would have a rated capacity of 300 kW. It would require an initial investment of $3.3 million (at January 1981 prices). Excess electricity avail- able from the plant could be used by the local processing plant, thereby displacing diesel generation. If excess electricity could not be sold, the project would be less desirable. A more detailed investigation is needed to determine the feasibility of the Humpy Creek hydropower project. This would include detailed aerial mapping and streamflow measure- ment programs (streamflow measurement programs are currently under way). Data available from such programs could be used to refine project design and cost estimates. The feasibility investigation would cost approximately $80,000 to $120,000. A more detailed investigation is needed to determine the feasibility of a weatherproofing and insulation program, primarily for older housing. This investigation would include a more detailed characterization of current insula- tion levels, the general condition of the existing housing stock, an assessment of heating requirements, and an assessment of both the costs and expected results of alterna- tive 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 Facilities 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 Wood Combustion for Electrical Generation Peat Combustion for Electrical Generation Coal Combustion for Electrical Generation Solar Energy (Active Solar Heating and Electrical Generation) Decentralized Wood Burning for Residential Space Heating 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 Conclusions Detailed Descriptions of Preferred Electricity Sources vii Dew WWw La onn BR SCOWLD 11 11 11 13 13 13 16 16 17 TABLES 1 Forecast of Annual Energy Requirements for Larsen Bay 2 Preliminary Evaluation of Alternative Energy Sources for Larsen Bay 3 Alternative Electricity Supply Plans for Larsen Bay 4 Evaluation of Alternative Electricity Supply Plans for Larsen Bay FIGURES 1 Annual Energy Balance for Larsen Bay ix 12 14 15 MM chapter 1 INTRODUCTION Alternative sources of electricity for the community of Lar- sen Bay 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 depen- dence on expensive and often scarce diesel fuel for elec- trical generation. The purpose of the study was to recommend a series of activ- ities that will result in the identification of feasible alternative sources of electricity. The sources studied include wind generation; peat, wood, 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 Larsen Bay's future demands for electricity. Electrical demands of the school were included in these plans. Each plan was assessed on the basis of its technical, economic, environmental, social, and institutional 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. MMe chapter 2 MM EXISTING AND PROJECTED ENERGY REQUIREMENTS The CH2M HILL project team visited Larsen Bay 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. Information was also obtained through interviews with the Kodiak Area “Native Association and the Kodiak Island Borough and was sup- plemented through review of published information and data. Interviews were conducted with several Kodiak Island Seafood, Inc. (KISI), officials who provided information about cannery electrical generation, fuel consumption, and fuel supplied to the residents of Larsen Bay. EXISTING ELECTRICAL GENERATION FACILITIES Larsen Bay does not have a centralized electrical system; approximately 20 individually owned and operated generators (5-kilowatt Listers) provide electricity to 25 to 30 house- holds. Electricity is usually generated only during the evening, or when there is a special need for it. Some households are heated with wood stoves. A new school, opened in 1980, has two Detroit Diesel 60-kilowatt (kW) generators. The KISI processing plant operits own generating Plant for cannery operations and employee housing. KISI operates a 7.5-kW Lister and a 30-kW Caterpillar diesel engine generator unit during the winter months and two 75-kW Caterpillar and three 200-kW Caterpillar units during the canning season. Residents expressed opinions that more effici- ent and less costly electric energy could probably be generated with a centralized system. The Tribal Council has identified hydroelectric development as the highest economic priority during 1981. ANNUAL ENERGY USE All diesel fuel deliveries are made to KISI. Fuel for home heating and operation of individual generators is distributed by KISI to the residents of Larsen Bay. Annual fuel deliv- eries were available for 1979; however, consumption by use had to be estimated. In addition, generation and related fuel use for the new school generation plant were not in- cluded in 1979 data and had to be estimated. Bulk fuel storage facilities are owned and operated by KISI. This implies that residents depend on KISI for fuel for home electric and heat generation. Fuel for village generation, estimated by residents to be approximately 110 gallons per generating unit per month, totaled 480 barrels. Annual generation was estimated to be 132,000 kilowatt-hours (kWh), through use of a conversion factor of 5 kWh per gallon. Home heating was estimated to consume 900 barrels, at a consumption rate of 110 gallons per household per month in the summer and 220 gallons per household per month in the winter. End uses of electricity include lighting and the operation of appliances such as refrigerators, freezers, televisions, washers, and dryers. End uses of fuel include heating, cooking, and water heating. Some stoves may be fueled with propane. Some houses have wood stoves for space and water heating. School generation was estimated at 131,000 kWh, at an assumed average demand of 15 kW. Fuel use for school generation was calculated through use of a conversion factor of 8 kWh per gallon. Fuel use by cannery generation (1,200 barrels) was calculated by subtracting from total deliveries the fuel used for village generation and heating. Annual cannery genera- tion was estimated to be 527,100 kWh. In addition to fuel deliveries to KISI, fishing vessels often fuel at Kodiak and resell the fuel at Larsen Bay. This fuel use is not reflec- ted in the total fuel deliveries because there was no reli- able basis for estimating the additional cannery consumption. Figure 1 summarizes energy information for Larsen Bay. DEMOGRAPHIC AND ECONOMIC FORECAST The population of Larsen Bay is projected to increase at 5 percent per year through 1985 and at 3 percent per year from 1985 through 2000. Housing is expected to increase at a somewhat higher rate than population over the next 20 years. Average household size in 1980 was estimated at 4.0 people. The housing stock is expected to grow at a slightly higher rate than the popu- lation, which will allow for a decrease in the average number of people per household and a slight increase in the vacancy rate. A 12 percent average annual increase in housing units is expected for 1981 through 1985 on the basis of known plans for construction. Increases are estimated at 4 percent per year between 1986 and 2000. Asa result, the number of houses is estimated to nearly triple in the next 20 years, from 30 to 84, The preceding estimates of future population levels and housing requirements depend on future economic activity and land use patterns. As long as it is difficult for individ- uals to acquire and own land on which to build a house, growth in population and housing will be slower than other- wise. It has been assumed that, within the next 4 years, arrangements conducive to land ownership and housing con- struction will be made. IMPORTS END USE MOTOR VEHICLE AND ‘ GAS |— 27,000 GAL OTHER USE 3,375 x 10° Btu —_— NON-RECOVERABLE GENERATION WASTE HEAT 9,858 x 10° Btu DIESEL FUEL |+- 2,877 bbl RECOVERABLE GENERATION WASTE HEAT 3,100 x 10° Btu CITY GENERATION 132,000 Kwh CANNERY GENERATION SCHOOL GENERATION|— 131,400 Kwh 527,100 Kwh CITY HEATING 7,128 x 10° Btu FIGURE 1 ANNUAL ENERGY BALANCE FOR LARSEN BAY Some combination of subsistence lifestyle with seasonal fisheries-related employment opportunities is expected to continue, augmented by some small businesses or services (a store, for example). The long-term stability of the village economy depends on continued operation of the Kodiak Island Seafood, Inc., fish processing plant. Closure of the plant would cause significant changes in the projected rate of housing and population growth, and possibly even a decline in population. ENERGY REQUIREMENTS FORECAST Annual energy requirements for Larsen Bay were projected to the year 2000 (Table 1). Fuel use and electrical generation for all uses except seafood processing plant operations are projected to grow 12 percent annually from 1981 to 1985 and 4 percent annually from 1985 to 2000. Since it is not pos- sible to forecast the level of processing plant activity, fuel use for plant operations was projected to remain at the current level. Electrical generation for the village was projected to grow at a similar annual rate. Table 1 FORECAST OF ANNUAL ENERGY REQUIREMENTS FOR LARSEN BAY Fuel (bbl/yr)* 1980 1990 2000 Diesel (generation) 1,977 3,296 4,485 Diesel (heating) 900 1,501 2,042 Total 2,877 4,797 6,527 Generation (kWh/yr) Village 132,000 283,000 419,000 Cannery 527,100 527,100 527,100 School 131,400 281,700 417,000 Total 790,500 1,091, 800 1,363,100 Peak Electric Power Requirements (kW Village and School (largely decentral- ized generation) 100 215 320 *One barrel equals 55 gallons. MH chapter 3 ALTERNATIVE SOURCES OF ENERGY Alternative sources of electricity available to the commun- ity 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 decentralized diesel-electric generation Humpy Creek hydropower Waste heat recovery at the school central generating plant ‘ Central diesel-electric generation Installation of a central electricity distribution system Unnamed creek No. 1 hydropower Unnamed creek No. 2 hydropower Peat combustion for generation Wood combustion for generation Coal combustion for generation Decentralized solar-electric generation Induction wind generation Decentralized active solar heating Heat conservation Decentralized wood burning for space heating Single wire ground return electricity transmission ooo o0°o 00000000000 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 main- tain. Also, the cost of the electricity produced by a hydro- electric plant remains relatively constant over time. Costs rise only when inflation increases operation and maintenance costs, which constitute only a small portion of total plant costs. The major project cost is for initial construction, which can be financed and paid for in equal periodic pay- ments 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 collec- tor 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 considered 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 effici- ency, although investigations of individual residences would probably result in specific recommendations for particular dwellings. In older housing stock, existing structural com- ponents 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. WOOD COMBUSTION FOR ELECTRICAL GENERATION Wood can be harvested, processed, and burned for steam tur- bine generation or piston engine generation. The renewability of wood as a fuel depends on timber growth rates, forest den- sity, and the size of the forest area dedicated as a fuel source. Often, a very large area is required to fuel a municipal power plant, and a considerable amount of machin- ery and labor is needed to harvest and process the wood. The environmental costs can also be high. Harvesting can affect the land, water, and wildlife of the forest, and large-scale wood combustion can cause air pollution. PEAT COMBUSTION FOR ELECTRICAL GENERATION Dried peat can be used as boiler fuel for steam turbine gen- eration 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 reli- able, 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 10 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 main- tenance 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. DECENTRALIZED WOOD BURNING FOR RESIDENTIAL SPACE HEATING Wood can be harvested, processed, and burned in household stoves for space heating. This is a very simple, reliable technology, but the attractiveness of wood as an energy source depends on timber growth rates, forest density, and the size of the forest area dedicated as a fuel source (driftwood can also be used). A very large area might be required to heat a community, and a considerable amount of labor and machinery is needed to harvest and process the wood. The environmental cost can also be high. Harvesting can affect the land, water, and wildlife of the forest, and can be quite noisy. 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 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, four preferred 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. 11 Table 2 PRELIMINARY EVALUATION OF ALTERNATIVE ENERGY SOURCES FOR LARSEN BAY Preferred Energy Sources (selected for further analysis) Continued decentralized diesel electric generation Humpy Creek hydropower Waste heat recovery at school central generating plant Central diesel-electric generation Installation of central electric distribution system Other Energy Sources (not considered further) Unnamed creek No. 1 hydropower Unnamed creek No. 2 hydropower Peat combustion for generation Wood combustion for generation Coal combustion for generation Decentralized solar-electric generation Induction wind generation Decentralized active solar heating Heat energy conservation Decentralized wood burning for space heating Note: Important Characteristics No initial investment required High reliability Proven technology See note below Small initial investment required Low operating cost/no fuel cost No significant adverse environmental impacts High reliability Proven technology Minimal initial investment required Higher conversion efficiencies than decentralized generation High reliability Proven technology Necessary with central diesel electric generation 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 invest- ment requirement Unproven technology High initial investment requirement Not an electricity generation source and thus not considered further Humpy Creek is the preferred hydropower project because of community preference, relatively low cost, and minimal environmental impact. 12 MM Chapter 4 MM EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY PLANS This chapter identifies and evaluates alternative elec- tricity supply plans. The plans use the preferred energy sources described in Chapter 3 to meet both the peak elec- trical demands and annual energy requirements of the village and school. Plans were not developed to meet the relatively large electrical demands of the seafood processing plant. Continued use of existing diesel engine generation is con- sidered an alternative supply plan and is identified as Plan A, Base Case. Supply plans to meet future space-heating require- ments 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 guidelines, 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 planning 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 average 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: ° Air quality ° Water quality 13 vT Plan A (Base Case) Table 3 ALTERNATIVE ELECTRICITY SUPPLY PLANS FOR LARSEN BAY Plan Description Continue existing decentralized generation (5-kW units) in village. Continue to meet school electric load using existing 60-kW engine generator units located at school. Add two 5-kW engine generator units per year to meet village electric load ($6,000 per unit). Replace one 5-kW engine generator unit per year ($6,000/unit). Replace one 60-kW engine generator unit at school in 1996 ($400/kW). Install and operate village central diesel generation plant. Install village central electric distribution system. Continue to meet school electric load using existing 60-kW engine generator units located at school. Install two 120-kW engine generator units in 1982 ($800/kW) for startup in January 1983. Install central village electric distribution system in 1982. Add one new 120-kW engine generator unit in 1996 ($600/kW). Replace one 120-kW engine generator unit in 1998 ($400/kW). Replace one 60-kW engine generator unit at school in 1996 ($400/kW). Develop and operate Humpy Creek hydropower plant for village and school service. Install central village electric distribution system. Plan and license hydropower project in 1981 and 1982; costs are approximately $50,000 in 1981 and $100,000 in 1982. Install/construct hydropower plant 1983 and 1984. Plant available in January 1985. Install central village electric distribution system in 1982. Backup generation from a new central diesel generation plant. Install one 120-kW engine generator unit in 1982. Minimum diesel backup plant operating, maintenance, and fuel cost is $10,000 per year. Excess electric energy sold to local cannery and processing plant during period from 1985 to 2000. Total energy sales over period of 8.0 million kWh. Install and operate waste heat recovery system at school generation plant to provide school heating. Continue use of decentralized diesel generation (5-kW unit) in village. Planning and installation in 1981. Available in January 1982. Decentralized diesel unit replacement and additions schedule same as Plan A. Note: All costs are based on January 1981 price levels. ST Table 4 EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY PLANS FOR LARSEN BAY 20-Year Planning Period Present Value of Plan 50-Year Planning Period Present Value of Plan Plan Plan Description Costs ($)? Costs ($)* Energy Performance Environmental Impacts Reliability/Safety A Continued decen- 2.47 million 6.20 million Sufficient to meet com- No major impacts; some Highly reliable, minor (Base _tral-diesel-elec- munity (village and noise emissions safety concerns Case) tric generation school) electric re- quirements B Central diesel 2.22 million 5.11 million Sufficient to meet com- No major impacts Highly reliable; minor generation munity (village and safety concerns school) electric requirements c Humpy Creek 3.30 million (plan 5.21 million (plan Sufficient to meet com = Potentially adverse en- ‘Highly reliable; backup hydropower cost) cost) munity (village and vironmental impacts. An with central diesel gen- project +95 million (energy 2.18 million (energy school) electric existing concrete diver- eration. Some safety con- sales credit) sales credit) requirements sion dam currently cerns regarding seismically 2.35 million (net million (net blocks upstream move- induced structural failure. plan cost) plan cost) ment of salmon. Dam located downstream of Proposed hydropower site. Pink salmon spawn in lower portions of the stream and could be affected by siltation caused by project con- struction and operation D Waste heat 2.66 million (plan 6.50 million (plan Sufficient to meet school No major impact recovery from school electric generation plant cost) 0.10 million (heat- ing credit) 2.56 million (net plan cost) “January 1981 costs. cost) 0.22 million (heating —_ credit) 6.28 million (net plan cost) and village electric requirements and displace 70 barrels of heating oil per year Highly reliable; minor safety concerns Fish and wildlife Land use Terrestrial Community infrastructure and employment Other planned capital projects oo0000 Detailed estimates of the magnitude of an impact were not possible. However, major concerns are identified and included in the evaluations. Alternative energy systems were designed to be environmentally acceptable. In those instances where additional equipment was required to make a source acceptable, the costs of such equipment were included in cost estimates. Detailed descriptions of possible environmental 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. CONCLUSIONS From the information in Table 4, the Humpy Creek hydropower project appears to be economically feasible. When evaluated over a 50-year planning period, this project has a present- value cost of $5.21 million, which compares favorably with the $6.20 million for continued decentralized electric gen- eration. Excess electricity available from the Humpy Creek project could be sold to the local seafood processing plant, which would displace diesel generation within the plant. If the Humpy Creek hydropower project is not developed, cen- tral diesel generation appears to be an economical resource in place of continued vilage decentralized generation. In comparisons based on both 20- and 50-year planning periods, the present value of the cost of central diesel generation is less than that of continued decentralized generation. 16 MM Appendix MM DETAILED DESCRIPTIONS OF PREFERRED ELECTRICITY SOURCES 17 Resource/Village: Continued decentralized diesel generation/Larsen Bay Energy Form: Electric energy General Description: Continued use and installation (where required to meet elec- tric load growth) of privately owned decentralized small diesel engine generators (approximately 5-kW peak output per unit). Resource Location: Larsen Bay Renewable or Nonrenewable: Nonrenewable Resource Characteristics: NA Energy Production: Approximately 3-kw average electric output per unit,; units operate 6 to 8 hours per day; approximately 7,700 kWh per unit per year Input Energy (fuel) Characteristics: Average conversion efficiency is 7 kWh per gallon fuel oil Resource Reliability: Highly reliable from an operating standpoint; questionable availability of fuel supply Resource Cost (January 1981 price levels): Equipment purchase and replacement per unit ($) 6,000 Carrent fuel cost ($/gal.) 1.40 Maintenance Requirements: Maintenance routinely performed by owner/operator Resource Development Schedule: Immediate Environmental Impacts: Some noise emission from diesel engine operation Institutional, Social, and Land-Use Considerations: Decentralized generation oper- ated privately approximately 6 to 8 hours per day, thereby limiting availability of electric energy. Health and Safety Impacts: No major impacts 19 Resource/Village: Energy Form: Electric energy General Description: Hydropower plant on Humpy Creek/Larsen Bay , A low concrete dam diverts water from Humpy Creek into a penstock leading 2,400 feet downstream to a powerhouse near the old water supply dam. Resource Location: above mouth of Humpy Creek 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) Energy 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) Resource Reliability: Dam 1.0 mile above the mouth of Humpy Creek; powerhouse 0.5 mile Concrete diversion 10 Run-of-river Concrete overflow 3,200 (double 500-year peak flow) 2,400 24 Reaction 1 300 Single wire, ground return 0.5 300 1,688,000 66 58 1,350,000 2,026,000 4.2 16.8 2.9 1,220 210 200 21 The froject 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 pr Construction and engineering ($) Unit cost ($/kwW) Annual operating and maintenance Maintenance Requirements: replace worn-out or defective parts. ice levels): 3,113,000 10,380 63,000 Periodic maintenance will be required to overhaul or 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. Resource Development Schedule: available in January 1985 Useful operating lifetime is 30 to 50 years. Installation and construction in 1983 and 1984, Environmental Impacts: An existing concrete diversion dam built in the late 1880's for water supply blocks upstream movement of salmon. of the proposed hydropower site. The dam is located downstream Pink salmon spawn in the lower portions of the stream and could be affected by siltation and sedimentation during construction and changes in flow and water temperatures during operation. Institutional, Social, and Land-Use Considerations: Possible land-use conflicts resulting from siting plant and transmission system. Health and Safety Impacts: to life and property in Larsen Bay. 21 Seismically induced structural failure could cause risk Resource/Village: Waste heat recovery - School generating plant/Larsen Bay. Energy Form: Hot water General Description: Reclaim exhaust and jacket water heat fram two existing 60-kW engine generators (school). Use hot water (200°F) to heat school interior. Resource Location: Larsen Bay School Renewable or Nonrenewable: NA Resource Characteristics: Resource components are (1) 200 feet of 3-inch-diameter outside pipe (insulated), (2) 400 feet of 2-inch-diameter interior piping, (3) four hot water unit heaters (100,000 Btuh rating), (4) one heat recovery silencer, (5) one heat exchanger (shell and tube type), (6) one building hot water circulation pump, (7) one expansion tank (20-gallon), and (8) one Butler-type building with concrete floor slab. Energy Production: Approximately 98,000 Btu per hour hot water production at 15- to 20-kW average electric output (school generation only). Average heat available at school is 88,000 Btu per hour. Annual energy (fuel) saving is estimated at 30 million Btu (3,700 gallons No. 2 fuel oil). Input Energy (fuel) Characteristics: System operates using engine stack exhaust and jacket water heat fram school generation plant. Resource Reliability: Highly reliable Resource Cost (January 1981 price levels): Construction and engineering ($) 145,000 Annual operating and maintenance ($) 5,500 Maintenance Requirements: No additional generation plant operators required. Inspect piping, valves, unit heaters monthly. Visually check heat recovery system whenever engine is checked. Four weeks' maintenance (one person) required per year. Average equipment replacement cost is $900 per year. Resource Development Schedule: Installation and construction in 1981, available in January 1982 Environmental Impacts: No major impacts Institutional, Social, and Land-Use Considerations: No major considerations Health and Safety Impacts: No major impacts 23 Resource/Village: Central diesel-electric generation for the village only/Larsen Bay Energy Form: Electric energy General Description: Install and operate a central diesel electric generation plant to service village load. Resource Location: Larsen Bay Renewable or Nonrenewable: Nonrenewable Resource Characteristics: Install two 120-kW engine generator units in 1982. Energy Production: Overall estimated conversion efficiency is 10.5 kWh per gallon fuel oil. Input Energy (fuel) Characteristics: NA Resource Reliability: Engine generator unit(s) highly reliable; questionable avail- ability of diesel fuel supply Resource Cost (January 1981 price levels): Construction and engineering ($/kWh) 800 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: Installation in 1982, available January 1983 Environmental Impacts: No major impacts Institutional, Social, and Iand-Use Considerations: No major considerations Health and Safety Impacts: No major considerations 25 Resource/Village: Installation of a central electric distribution system/Larsen Bay Energy Form: NA General Description: Installation of a central electric distribution system (4,160- volt) to provide electric service to all village residences and other building units. Generation equipment not included. Resource Location: Larsen Bay Renewable or Nonrenewable: NA Resource Characteristics: Distribution system sized to service 50 demand units with 3-kw peak load per unit, 55 poles, 11,000 1f conductor required Energy Production: None Input Energy (Fuel) Characteristics: NA Resource Reliability: NA Resource Cost (January 1981 price levels): Construction and engineering ($) 142,000 Maintenance Requirements: Periodic maintenance required Resource Development Schedule: Installation in 1982, available in January 1983 Environmental Impacts: No major impacts Institutional, Social, and Land-Use Considerations: No major considerations Health and Safety Impacts: No major impacts 27