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HomeMy WebLinkAboutSand Point Reconnaissance Study of Energy Requirements & Alternatives 7-1981 Summary Reconnaisance Study of Energy Requirements & Alternatives for Sand Point Prepared For July 1981 Alaska Power Authority CH2MssHILL ALASKA POWER AUTHORITY STEEN ei . ss aa Pens beth ns iacdeaao ISSUED TO HIGHSMITH — 42-225 Summary Reconnaisance Study of Energy Requirements & Alternatives for Sand Point Prepared For July 1981 Alaska Power Authority CH2M#EHILL ALASKA POWER AUTHORITY iil MM PREFACE This summary contains the results of a study evaluating energy requirements and alternative electricity sources for the com- munity of Sand Point near the Alaska Peninsula. 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 Alter- natives 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 Develop- ment, Alaska Power Authority, in a contract with CH2M HILL signed October 9, 1980. iii (el fas MM RECOMMENDATIONS Sand Point is located on Popof Island off the southern coast of the Alaska Peninsula. The city has a year-round popula- tion of approximately 610. In recent years the village has grown, and it is expected to continue to grow, largely because of Pacific Pearl Seafoods' processing plant activities and improvements to the boat harbor. The current source of elec- tricity for the city is a diesel generation plant that con- sists of two 400-kilowatt (kW) and two 500-kW diesel engine generators. Current peak electrical requirements are approxi- mately 400 kW; these are expected to grow to 1,100 kW in the year 2000. The preferred supply source is continued central diesel gen- eration and installation of an induction wind generator, which will supply approximately 25 percent of the community's elec- tricity needs. The proposed Humbolt Creek hydropower project appears to be an uneconomic generation source because of the small amount of energy it would produce. Initial investment requirements for the hydropower project would be approximately $2.2 million (at January 1981 prices). Induction wind generation, which appears to be a marginally economic supplement to existing diesel engine generation, would generate an average of approximately 75 kW. The power plant would consist of four horizontal-axis wind generators, each with a rated output of 40 kW. Initial investment re- quirement would be approximately $1.4 million (at January 1981 prices). Recovery of waste heat from the exhaust stack of the city generating plant might be a marginally economic way to heat nearby buildings such as apartments. Evaluations show that such an energy source would displace approximately 330 bar- rels of heating oil per year and would have an initial cost of approximately $345,000 (at January 1981 prices). A wind monitoring program should be undertaken to establish the characteristics of the wind. Towers equipped with wind measuring and recording equipment should be erected at sev- eral locations around Sand Point. The program would require at least 1 year of monitoring at a cost of approximately $15,000. An investigation is needed to determine the feasibility of waste heat recovery at the city generating plant. This would include development of preliminary layouts for equipment, assessment of the specific heating needs of potential users of the heat, and development of refined cost estimates for the recovery equipment. This study would cost about $30,000. 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 assess- ment of both the costs and expected results of alternative 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 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 Conclusions Detailed Descriptions of Preferred Electricity Sources vii onn PW WwW Be CowWW 10 11 13 13 13 16 16 17 TABLES 1 Forecast of Annual Energy Requirements for Sand Point 2 Preliminary Evaluation of Alternative Energy Sources for Sand Point 3 Alternative Electricity Supply Plans for Sand Point 4 Evaluation of Alternative Electricity Supply Plans for Sand Point FIGURES 1 Annual Energy Balance for Sand Point ix 12 14 15 WM Chapter 1 MM INTRODUCTION Alternative sources of electricity for the community of Sand Point on the Alaska Peninsula were identified and evaluated in the study summarized by this report. The sources recom- mended for further study could help the community reduce its dependence on expensive and often scarce diesel fuel for electrical 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 and coal combustion for elec- trical generation, small hydroelectric generation, tidal 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 Sand Point'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 per- formed 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. MM Chapter 2 MM EXISTING AND PROJECTED ENERGY REQUIREMENTS The CH2M HILL project team visited Sand Point 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 facility was conducted to determine the nature and condition of the generating plants. Pacific Pearl Seafoods also provided information regarding processing plant fuel consumption, total fuel deliveries, and fuel supplied to the community. Additional information was obtained from published sources and interviews with local planners. EXISTING ELECTRICAL GENERATION FACILITIES Pacific Pearl Seafoods owns and operates the generation plant and distribution system for the city and the generation plant for the processing plant. The city generating system, con- sisting of two 400-kilowatt (kW) Caterpillar units and two 500-kW Caterpillar units, is in good condition and has an excellent record of minimal downtime. The processing plant's system consists of one 800-kW unit in good condition and three 200-kW standby units. Distribution is via a 480-volt and 2,400-volt system. Residents expressed concern over the high cost of electrical energy in Sand Point. The monthly payments for electricity were said to average $100. ANNUAL ENERGY USE All fuel is delivered to Pacific Pearl Seafoods and distrib- uted by the plant to city residents. Annual fuel consump- tion records show deliveries of 8,060 barrels of diesel fuel, 13,100 barrels of home heating fuel, and 70,200 gallons of gasoline. Total electrical generation and related fuel con- sumption records for the city and cannery plants were avail- able; however, consumption in other use categories had to be estimated. Plant records revealed generation plant consumption of 12.5 kilowatt-hours (kWh) per gallon. Annual diesel fuel con- sumption for electric generation was estimated at 2,575 barrels for city generation (1,770,000 kWh) and 4,990 bar- rels for cannery generation (3,430,000 kWh). Included in cannery generation is electricity consumed by users in the harbor area. Approximately 70 slips are individually metered and use approximately 100 kWh per month. Diesel consumption of 490 barrels over and above generation use was classified as "other." A peak demand of 410 kW was estimated as was a system load factor of 50 percent. Residential end uses of electricity include lighting and the operation of appliances such as refrigerators, freezers, tele- visions, washers, and dryers. End uses of heating fuel include space heating and hot water heating. Figure 1 summarizes energy information for Sand Point. DEMOGRAPHIC AND ECONOMIC FORECAST Population is projected to increase at an average annual rate of 3 percent between 1981 and 2000. This average rate of increase appears reasonable on the basis of the increase exper- ienced since 1961. Housing stock is expected to grow at a somewhat higher rate than population during the next 20 years. This will allow for a decrease in average household size and an increase in housing market flexibility (a vacancy rate greater than zero). These estimates are based on projections provided by local planners. Increases are projected at the rate of approxi- mately 40 units per 5-year period. The projections of population and housing requirements are dependent on future levels of economic activity and land availability. As long as it is difficult for individuals to acquire land on which to build a house, growth in housing (and perhaps population) will be constrained. It has been assumed that within the next 4 years land will become avail- able for purchase for home sites. Employment opportunities are expected to increase during the next 20 years. Future employment opportunities appear pos- sible in fishing (dependent on many external conditions), mining (particularly if Apollo mine employees become perma- nent Sand Point residents), and local businesses and ser- vices. Development of oil and gas on the outer continental shelf might provide an additional opportunity for local economic development. A lease sale in the Bristol Bay area of the northern Aleutian Shelf is scheduled for October 1983. If these opportunities are not realized, and if the amount of land available for private use does not increase, future population and housing construction might be significantly lower than projected. ENERGY REQUIREMENTS FORECAST Annual energy requirements for Sand Point were projected to the year 2000 (Table 1). Fuel use and electrical generation IMPORTS MOTOR GAS 70,200 GAL DIESEL FUEL }— 8,056 bbl HOME HEATING +— 13,107 bbl FUEL END USE VEHICLE AND 6 OTHER USE 8,775 x 10° Btu NON-RECOVERABLE GENERATION WASTE HEAT 21,058 x 10° Btu RECOVERABLE GENERATION WASTE HEAT 21,100 x 10° Btu 1,770,000Kwh 3,430,000 Kwh CITY GENERATION CANNERY GENERATION CITY HEATING 72,706 x 10° Btu CANNERY MISC. USE 31,102 x 10° Btu MISC. CITY USE 3,889 x 10° Btu FIGURE 1 ANNUAL ENERGY BALANCE FOR SAND POINT for all uses except seafood processing plant operations are projected to increase at an annual rate of 5 percent from 1980 to 2000. Since it is not possible to forecast the level of processing plant activity, fuel use for plant operations was projected to remain at the current level. The result is an increase in total fuel use of approximately 20,200 barrels, representing a 165 percent increase in fuel requirements for non-processing-plant uses and a 95 percent increase in total fuel requirements. Generation for the city was projected to increase at similar rates. The peak demand for electricity was projected with an assumed continuation of the current load factor of 50 percent. Table 1 FORECAST OF ANNUAL ENERGY REQUIREMENTS FOR SAND POINT Fuel (bbl/yr)* 1980 1990 2000 Diesel (generation) 8,056 9,984 13,125 Home Heating Fuel (heating) 13,107 18,880 28,284 Total 21,163 28,864 41,409 Generation (kWh/yr) City 1,770,000 2,883,100 4,696,300 Cannery 3,430,000 3,430,000 3,430,000 Total 5,200,000 6,313,100 8,126,300 Peak Electric Power Requirements (kw) City 400 660 1,072 *One barrel equals 55 gallons. MM Chapter 3 MIM ALTERNATIVE SOURCES OF ENERGY Alternative sources of electricity available to the commun- ity are identified and described in this chapter. The accur- acy of these descriptions is consistent with the amount of data available from site investigations and research on the alternatives. Continued use of centralized or decentralized diesel electric generation is included as an alternative. Near-term alternative heat energy sources are also identi- fied and characterized. Specific alternative energy supply projects that were con- sidered include: Continued central diesel electric generation Humboldt Creek hydropower Waste heat recovery at the central generating plant Unnamed creek hydropower Peat combustion for generation Coal combustion for generation Decentralized solar-electric generation Decentralized active solar heating Heat conservation Single wire ground return electricity transmission eoo00000000 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 exposed to the elements, require more frequent maintenance than con- ventional 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 proxim- ity" to the generator (that is, if the cost of capturing, transporting, 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 ex- changer captures exhaust stack heat. The heat is transferred 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 building 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, existing structural components do not provide adequate thermal efficiency. The major oppor- tunity 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 generation 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 considered a renewable energy resource, but the degree of renewability 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 envi- ronmental costs can also be high. Harvesting can affect the land, water, and wildlife of the peat field, and peat com- bustion 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 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 sys- tems 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 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. 10 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 pre- ferred 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 SAND POINT Preferred Energy Sources (selected for further analysis) Continued centralized diesel-electric generation Humbolt Creek hydropower Induction wind generation Waste heat recovery at central generating Plant Other Energy Sources (not considered further) Unnamed creek hydropower Peat combustion for generation Coal combustion for generation Decentralized solar-electric generation Decentralized active solar heating Heat energy conservation Important Characteristics No initial investment required No significant environmental impacts High reliability Proven technology See note below Low operating cost/no fuel cost No significant adverse environmental impacts Small initial investment required Low operating cost/no fuel cost No significant adverse environmental impacts High reliability Proven technology Important Characteristics 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 Not an electricity generation source and thus not considered further Note: Humbolt Creek site was selected as the preferred hydropower project because unnamed creek was considered an uneconomical generation resource by the Corps of Engineers (October 1980). 12 MM chapter 4 MM EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY PLANS This chapter identifies and evaluates alternative electricity supply plans. The plans use the preferred energy sources described in Chapter 3 to meet both peak electrical demands and annual energy requirements of the city. Plans were not developed to meet the electrical demands of the large sea- food processing plant. Continued use of existing diesel engine generation is considered an alternative supply plan and is identified 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 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 tT Table 3 ALTERNATIVE ELECTRICITY SUPPLY PLANS FOR SAND POINT Plan Plan Description A Continue use of central diesel generation. (Base Case) Replace two 500-kW units in 1990 ($400/kW). B Install and operate Humbolt Creek hydropower plant. Plan and license hydropower project 1981 and 1982; costs are approximately $50,000 in 1981 and $100,000 in 1982. Install and construct hydropower plant in 1983 and 1984. Plant available in January 1985. Backup generation from existing central diesel plant. c Install and operate waste heat recovery system at city generating plant to provide space heating at nearby apartment complex. Continue use of city central diesel generation. Planning and installation in 1981. Available in January 1982. Diesel plant replacement schedule same as Plan A. D Develop and operate induction wind generation facility. Maximum wind generation contribution to village electric load will be 25 percent. Plan wind generation project 1981 and 1982; cost is approximately $50,000 per year. Install and construct wind generation facility in 1983 and 1984. Facility available in January 1985. Replace wind generation equipment in 1998 and 1999 ($660,000). Remaining generation from central diesel-electric plant. Diesel plant replacement schedule same as Plan A. Note: All costs are based on January 1981 price levels. ST Table 4 EVALUATION OF ALTERNATIVE ELECTRICITY SUPPLY PLANS FOR SAND POINT 20-Year Planning Period Present Value of Plan 50-Year Planning Period Present Value of Plan Plan _Plan Description Costs ($)* Costs ($)* Energy Performance Environmental Impacts Reliability/Safety A Continued central 7.86 million 20.22 million Sufficient to meet com- No major impacts Highly reliable, minor (Base diesel-electric munity electric re- safety concerns Case) generation quirements B Humboldt Creek 8.78 million 21.29 million Sufficient to meet com Potentially adverse Highly reliable, backup hydropower munity electric environmental impacts. with central diesel gener- project requirements Known spawning area for ation. Major safety con- coho salmon. Existing cerns regarding seismically gravelfill dam at pro- induced dam structural posed site currently may failure. impede passage of salmon upstream. Coho salmon below damsite could be adversely affected by streamflow fluctuations and siltation caused by project construction and operation. c waste heat 8.19 million (plan 20.70 million (plan Sufficient to meet com- No major impacts Highly reliable, minor recovery with cost) cost) munity electric re- safety concerns central diesel- .43 million (heat- 0.92 million (heating quirements and displace electric ing credit) credit) approximately 330 barrels generatin 7.76 million (net 19.78 million ( net of heating oil per year plan cost) plan cost) D Induction wind 8.21 million 19.87 million Sufficient to meet com- Minor adverse environmen- Questionable reliability generation (25%) with central diesel generation (758) Ajanuary 1981 costs. munity electric re- quirements levels can be mitigated by remote location siting. tal impact. Some noise during operation. Noise backup with central diesel generation. Minor safety concerns with remote siting. resulting from variations in wind availability, Fish and wildlife Land use Terrestrial Community infrastructure and employment Other planned capital projects o0o0000 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 accept- able, the costs of such equipment were included in cost esti- mates. 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 elec- tricity 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, an induction wind genera- tion system appears to be economically feasible. When evalu- ated over a 50-year planning period, this project, which would supply about 25 percent of the community's electricity needs, has a present-value cost of $19.87 million. This compares favorably with the cost of continued central diesel generation. Waste heat recovery at the city diesel generation plant also appears to be an appropriate energy source. Over a 50-year planning period, a waste heat recovery system has a present- value cost of $19.78 million, which compares favorably with the $19.87 million for continued electricity generation with- out waste heat recovery. 16 MM Appendix MM DETAILED DESCRIPTIONS OF PREFERRED ELECTRICITY SOURCES 17 Resource/Village: Continued central diesel generation/Sand Point Energy Form: Electric energy General Description: Continued diesel electric generation with existing engine generator unit(s) Resource Location: Sand Point Renewable or Nonrenewable: Nonrenewable Resource Characteristics: Existing city diesel generation plant consists of two 400-kW engine generator units and two 500-kW engine generator units. Energy Production: Overall estimated conversion efficiency is 12 kWh per gallon of fuel oil consumed. Input Energy (fuel) Characteristics: NA Resource Reliability: Engine generator unit(s) highly reliable; questionable avail- ability of diesel fuel supply Resource Cost (January 1981 price levels): Replacement cost ($/kW) 400 Operating and maintenance cost (¢/kWh) 2.6 Current fuel cost ($/gal.) 1.20 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: Hydropower plant on Humbolt Creek/Sand Point Energy Form: Electric energy General Description: An embankment on the stream forms a reservior that serves as the city water supply. Hydropower development will require reconstruction of the water supply intake and possibly the pump station. The embankment will be raised to increase the reservoir level from its present average elevation of 33 feet NGVD to an elevation of 50 feet NGVD. The channel below the existing embankment will be excavated to provide an average tailwater elevation of 10 feet NGVD. The creek supports salmon, but reportedly the salmon cause a water quality problem after completing their spawning cycle. The entire existing embankment should probably be replaced because the quality of its construction is unknown. Raising the reservoir level higher than elevation 50 would create a large very shallow lake with water quality and freezing problems. Present lake level is 33 feet NGVD with a surface area of about 3 acres (estimated storage, 15 acre-feet). Raising the reservoir level to 50 feet would give a total storage of about 100 acre-feet. Resource Location: 0.1 mile above mouth of Humbolt Creek Renewable or Nonrenewable: Renewable Resource Characteristics: am Type Earthfill Height (ft) 45 Operation Storage Spillway Type Concrete chute Capacity (cfs) 1,700 (500-year peak flow) Penstock Length (ft) 175 Diameter (in) 24 Powerhouse Type of machine Propeller Number of units 1 Installed capacity (kW) 70 Transmission Facilities Type Single wire, ground return Length (miles) 0.5 Energy Production: Installed capacity (kW) 70 Average annual energy (kWh) 303,000 Plant factor (%) 50 Dependable capacity (kW) 10 Annual energy, low-flow year (kWh) 242,000 Annual energy, high-flow year (kWh) 364,000 Input Energy (Fuel) Characteristics: Drainage area (sq. mi.) 5.1 Average annual flow (cfs) 20 Low flow (cfs) 3.5 High flow (cfs) 1,275 Total head (ft) 40 Net head (ft) 38 Maximum penstock flow (cfs) 24 Resource Reliability: area, and it is sized The project is located on a stream with a small drainage to use most of the available flow. of the plant is subject to natural fluctuations in runoff. to carry over generation capability during dry periods. For this reason the output The project has storage Resource Cost (January 1981 price levels): Construction and engineering ($) 2,028,000 Unit cost ($/kW) 28,970 Annual operating and maintenance 18,800 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 proejcts 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: Known spawning area for coho salmon. Existing gravel-fill dam at proposed site may currently impede passage of salmon upstream. Coho salmon below damsite could be adversely affected by streamflow fluctuations and siltation caused by project construction and operation. Installation and construction in 1983 and 1984, Institutional, Social, and Land-Use Characteristics: resulting from siting plant and transmission system. Possible land-use conflicts Health and Safety Impacts: Seismically induced structural failure could cause risk to life and property in Sand Point harbor area. 21 Resource/Village: Wind generation/Sand Point Energy Form: Electric energy General Description: Installation and operation of horizontal axis wind induction generator(s) to provide approximately 80-kW average power output. System induction to consist of four wind generators rated for 40 kW maximum output each, with support towers, control equipment, and transformation and transmission facilities to inte- grate into existing community electric distribution system. Wind generation to be backed by diesel generation to provide firm power base and for system integrity and reliability. Approximate maximum wind generation contribution to total system 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: Four 40-kW peak wind generation machines Energy Production: 40-kW peak output per machine, 19-kW average output per machine, 166 ,000-kWh-per~year electric energy output per machine, 664,000-kWh-per~year elec- tric 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 25 to 30 percent. Maintenance activity downtime estimated at 5 percent. Resource Cost (January 1981 price levels): Construction and engineering ($) 1,321,000 Unit cost ($/kW) 8,260 Annual operating and maintenance ($) 26,400 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 $5,000 per machine. Appr oxi- mate useful lifetime is 15 years. Resource Development Schedule: Installation in 1983 and 1984, available in January 1985 Environmental Impacts: Some noise emission during resource operation. Noise levels can be mitigated by strategic and remote location siting. Institutional, Social, and Land-Use Considerations: Possible land-use conflicts Institutional, Social, and Taner eon oyster resulting fran siting plant and transmission system. Health and Safety Impacts: No major impacts 23 Resource/Village: Waste heat recovery at the city generating plant/Sand Point Energy Form: Hot water General Description: Reclaim exhaust heat only from two existing 500-kw engine generators at city generating plant. Use hot water (200°F) to heat apartment cam- plex nearby. Resource Location: City generating plant, Sand Point Renewable or Nonrenewable: Not applicable Resource Characteristics: Resource camponents are (1) 800 feet of 3-inch-diameter outside pipe (insulated), (2) 450 feet of 2-inch-diameter inside pipe, (3) hot water unit heaters, (4) two heat recovery silencers, (5) two hot water circulation pumps, and (6) two expansion tanks (20-gallon). Energy Production: Approximately 1,500,000 Btu per hour hot water production at 300-kW average electric output. Average heat available at apartment complex is 1,350,000 Btu per hour. Sized to space-heat 30 apartment units, annual energy (fuel) saving is estimated at 2,590 million Btu (18,000 gallons No. 2 fuel oil). Input Energy (fuel) Characteristics: System operates utilizing engine stack exhaust heat from city generation facility. Jacket water presently being recovered for nearby bunkhouse space heating. Resource/Reliability: Highly reliable Resource Cost (January 1981 price levels): Construction and engineering (S$) 345,000 Annual operating and maintenance ($) 5,500 Maintenance Requirements: No additional generation plant operators required. Inspect piping, valves, and 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/construction in 1981, available begin- ning January 1982 Environmental Impacts: No major impacts Instituional, Social, and Land-Use Considerations: No major considerations Health and Safety Impacts: No major impacts 25