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HomeMy WebLinkAboutReconnaissance Study Of Energy Requirements & Alternatives-Main Report 1984> EK? 07-07 EE Copy RECONNAISSANCE STUDY OF ENERGY REQUIREMENTS AND ALTERNATIVES MAIN REPORT PREPARED BY FEBRUARY 1984 Mint | ALASKA POWER AUTHORITY __ TABLE OF CONTENTS Section Page A = INTRODUCTION .......ecceeeeeeee mole ele¥e! sievetetexe! sievote lols] oyorelele1sxererevere'e Toro 1 Bi = BACKGROUND) ierciere ciclcicicisio so sisiclaje/e ss sisiela soles aeletoeisteleleteretetletetetorertereiete 2 B.1 - Utility System Need and Objectives ..... sweats se saee ees 2 B.2 - Incorporating Changes in a Utility System ............... 2 B.3 - Centralized vs. Individual Heating Systems .............. 3 B.4 - Choice of Fuels ........46. Sislels/sielelolole) 6/aleleiolel4/ exe leloXelel 6 © oe [exate 4 B.5 - Utility Planning in Alaskan Villages ....... serie releieisia\e eele = C - METHODOLOGY ........ Bleieisicitetlstctsisteileictersielereletetereireletercisilereteretere axel 5 Gall = Data’ Collection sore iciereieie's oisicicicie’s osieieiel eielereraass Bfoelol 615 fal 5 Cad = Energy Balances 3. ccisice< scienins = 'er.c1e aig lolereisi elo{eelexbio 6/66 (6 \ee1s 5 C.3 - Energy Forecasts ..... alssisievslelsiaialereieiclelereleiolelelele/eleteielelelelereretelonnn dt C.4 - Energy Resource Evaluations ..... elefelel eye's elolele)® we felesele]6 ee [erete 12 C.5 - Energy System Plan Development .........cceccccccececcens 12 C6 = Cost lEstimatton ssccccisincccciciinas cleric Sr elelelelsioievslalsisicis\s cleieisen | 23 Gav = Economic Evaluation ccrwiciesscicccinscisicic dsc csisicsics siclsiclele cient D - SUMMARY ...... a elelelelelerelclevolelolelelelore\elelolelelsrcieletelo er oe ie (oloxs) ree" foro sisjesteire 120) Dal, = General) cacciwiisisitecsccinscleccs sialerelsielsle/sieletelolelel shoe eleiele) sieleceke 26 D.2 - Specific Recommendations for Elfin Cove........sseeeees oe a7 0.3 = Further Recommendations: o.)< <<< i0ic1c)0ciciisieic)o ieivisieio os elsiolniei vce 29 Ei =) MECHNOLOGY “PROFTUES) rains cretcis.c1e oe elcicis!ate <lolsieisicio'sisioisic sie cissisisis e's s)ole 31 E.1 - Steam-Electric Technologies ........sseeeees alerelerelote selene) OS E.2 - Hydrocarbon Based-E lectric Technologies w (0 (oleiel 0 Sie terol e6 eres AT, E.3 - Renewable Resource Based-Electric Systems .......eeeeeeee 55) E.4 - Heating Technologies ...... afolsleleielereersis)sleieissiele/oisisiclelsisicleleo nO E.5 - Fuel Conversion Technologies ....... HOCDOOO eieiekotetelorelerel stele 85 BG! = Other, TeChnOlOgdes: cic iciercic « cjelcieiela 0101s lelcieis oe sielolole)o\e(alcioisicle'e ele 97 F - SAMPLE VILLAGE TECHNOLOGY ASSESSMENT ...... SMPTE ES STITT SS TST S 104 page 1 A_- INTRODUCTION A large proportion of remote Alaskan community energy needs is met with oil fuels shipped into the villages. This use of oi] fuel is based upon convenience and cleanliness, but comes at no small price. Oil derived energy has become expensive in Anchorage and other major cities of the U.S., particularly for heating. When the costs of transporting oi] to remote areas are added, oi] supplies in small communities become very high priced. Some rural villages in Alaska receive No. 2 fuel oi] at prices approach- ing or exceeding $3.00 per gallon, compared to typical city costs of $1.25 per gallon. This oi] is often used to heat homes, schools and com- munity buildings, and to run the village diesel electric generators. Numerous residences in the state require over 200 gallons of fuel for heating in the coldest winter months. In some locations, the cost of diesel generated power used by residents exceeds $1.00/kWh and in a few cases approaches $2.00/kWh. Fuel costs are a significant portion of the cost of diesel generated power. Some communities depend totally on oil because no other resources are available or potential resources are undeveloped for various reasons. Other communities use locally available fuels such as wood extensively, but still require substantial quantities of oi] fuels. All users of oil based technologies are subject to world market prices and the risk of high price escalation rates. The high costs and risk of oi] heating and power production are problems commonly recognized by rural Alaskan residents and are being addressed by the Alaskan Energy Reconnaissance Study Program. The objective of stu- dies in this program is to identify possible energy technologies or fuel sources which can supply community electricity and heating needs at low- est cost. Emphasis is being given to methods~which reduce or displace the need for oi] in Alaskan communities. The report which follows documents one of several Village Energy Recon- naissance studies authorized by the Alaska State Legislature and perform- ed under the direction of the Alaska Power Authority. This report was produced by the Anchorage staff of Acres American Incorporated, a con- sulting engineering firm. page 2 SECTION B - BACKGROUND B.1 - Utility System Need and Objectives Existing Alaskan bush utility systems provide services at relatively high cost to the consumer (compared to urban costs for the same services) and residents seek improvement of the situation. The problem of high cost utility services has plagued communities in all parts of the world for centuries. Until the last hundred years, only adequate supplies of water and fuel for heating and cooking at acceptable cost (as well as sewer and garbage systems in large communities) were of common concern. Recent changes in technology and society have added electricity to the list of necessities. The objective of the first and all succeeding central utility systems was to provide needed services at a far lower cost than could be achieved by an individual acting alone. The central utility approach generally in- volves a sizeable initial investment combined with large reductions in operating costs to produce a lower overall monthly cost to the user. Whether government or privately owned, their purpose is to provide a service to a group of "individuals" at equal or greater reliability and lower cost. The user generally does not care who owns or operates the utility serv- ice. Even in small towns, few users take much interest in the operation of the utility unless they have reason to believe that they are paying an improperly large portion of their income for the basic service. In dis- cussions between village residents and reconnaissance field team members, it was noted that the residents' concerns are almost universally that the service be available when needed and that it be at lowest possible cost in terms of his time and money. These are the criteria of the customer and the objectives of the system, and should be used to evaluate any con- templated changes to a utility system. B.2 - Incorporating Changes in a Utility System Once the need for change is identified, there are three paths which can be taken: first, return to the old ways (abandonment); second, make do with whatever economy measures are possible and make gradual improvements as funds become available (conservation and upgrading); and third, invest in major improvements or replacements (start over). The major difference between selection of the three alternatives is financial - the availabil- ity of initial capital. page 3 The abandonment approach is often unacceptable, as the alternate method is often an even more costly use of money and time. The conservation and upgrading approach is often used as a compromise on full replacement and becomes increasingly necessary as centralization increases. The approach of major renovation/replacement is not often economically justified for centralized systems. For relatively new systems, this generally involves write off of existing but inadequate equipment. Such losses rarely can be absorbed by a utility operation, as virtually all of their funds are invested in the existing equipment. Adoption of the third approach also rarely involves replacement with a new technology much cheaper in cost; otherwise, it would likely have been installed in the first place. Thus, immediate replacement generally, but not always, results in greater initial costs charged to the consumer to cover both premature retirement losses on the old equipment and the cost of the new. In many cases the benefits of the new system do not become obvious for several years. The problems facing the utility system managers in evaluating proposed changes generally lie in defining how much capacity will be demanded by customers at any given time, and what "costs" should be compared in mak- ing decisions regarding equipment to be used. Underestimation of capac- ity needs will soon be confirmed, and may deny some users the benefit of the system as well as constrain growth and development of the local econ- omy if such growth is desired. Overestimation will burden the customers with higher costs than were truly needed, but will allow economic growth. To this end, government often subsidizes overcapacity for the long term growth and benefit of a region. B.3 - Centralized vs. Individual Heating Systems For some basic utility services a central system approach may be more costly and less desirable than individual systems. The most obvious ex- ample is residential heating. Centralized (district) heating is a reli- able and cost effective method in some densely populated areas of the world. However, the piping systems are exceedingly expensive for most suburban and rural areas, with the result that virtually all homes are individually heated by oil, gas, electricity, wood, coal, the sun, or some combination of the above. page 4 B.4 - Choice of Fuels Oil and gas are highly desirable fuels for residential heating because of their cleanliness and ease of use. In recent years oil and gas prices have escalated significantly for a variety of reasons, and little relief is in sight for the next several decades. As a result, homeowners are switching to what are perceived to be cheaper fuels. These "cheaper" fuels may be cheaper in the short term, but many have long term impacts which are potentially severe if ignored. As an example, in many areas the burning of wood is becoming more widespread. In areas with sparse forests and slow-growing trees, the annual demand for firewood is greater than can be supported by sustainable growth in the immediate village area. As a result, those people wishing to heat with wood must continu- ally go farther and farther to gather it. Widespread indiscriminate cut- ting of forests can decrease wildlife habitat. The value of leisure time can be great enough to alter the choice of fuels for home heating. Such fuels as wood generally require lower mone- tary expenditure, but require more of the user's time to gather, cut, split and transport the energy source than would be required to obtain oil or gas supplies. For some people, the self sufficiency and control of their energy supplies achieved by cutting wood, combined with the physical exercise are sufficient to offset the time required. For others, the dangers of wood cutting and the physical strength and time requirements are major deterrents, and they choose to suffer the cost in- creases of the existing systems. B.5 - Utility Planning in Alaskan Villages The provision of electricity and heating services to Alaska bush villages involves the same basic problems as those found in Anchorage, the lower 48 state communities, or foreign countries. The differences lie in the importance of time and money to the village residents, the resources available, the residents' specific objectives regarding standards of liv- ing and economic growth, and the types of systems which presently exist -in the villages. page 5 C_- METHODOLOGY The objective of the work covered by this report has been to identify en- ergy sources, conversion technologies, or conservation measures (if any) which will reduce the cost of electric energy in the villages under study. The work required to meet this objective involves a large number of data collecting, evaluation and decision steps. The process is out- lined in this section to illustrate both the wide range of information considered and the inherent limitations of these preliminary studies. The background work required was organized into the following separate tasks: (1) data collection (2) energy balance preparation (3) energy use forecasts (4) energy resource evaluation (5) energy system plan development (6) cost estimation (7) economic evaluation The results of these tasks were reviewed to determine possible options village by village. Activities within these seven tasks are, therefore, key to the conclusions, and are described in this section. C.1 - Data Collection Energy use data were collected from a variety of sources. The most im- portant sources were the villages being studied, which were each visited by a minimum of two people on the study team. Field data were supple- mented by documents available from various Alaska state agencies, reports of previous investigations in related topics, and discussions with fuel and electric utility companies. Resource and technology information was gathered from previous reconnais- sance studies and resource assessments, manufacturers and equipment vend- ors. C.2 - Energy Balances Once the required data were collected, energy balances were prepared us- ing an approach illustrated in Figure C.1. An energy balance is an as- sessment of all energy resources used (wood, oil, coal, hydroelectric, wind, etc.), and the uses to which the energy is put (space heating, TOTAL WHOLESALE CONSUME RS ENERGY PURCHASERS mee {sero kWh scHooLs 134000 | BTU/GAL. erase useruL COMMERCIAL’ ELECTRIC HEA ae Sent HOT WATER HEATING FUEL OIL OTICEEY (ELECTRIC HEATERS) NEAT ‘APPLIANCES, LIGHTS TOTAL NET Etc. HOT WATER HEATING outing OTHER USES (RUNNING WATER) STORES. HOT WATER HEATING ] 90.65 [WaSHETERIA, HOT WASHE TERIA, WATER WATER HEATING TANK - GROSS 410.65 NET qr035 SPACE HEATING GRO’ SPACE HEATING NET GROSS HOT WATER HEATING NET 9* 0.65) ar03s SPACE HEATING NET *0.35 17«10%BTu/coRD " on [SPACE HEATING GROSS SPACE HEATING NET COOKING AND HOT WATER CommeRciaL ~ RESIDENCES BTU/GAL. LEGEND » INDICATES DIRECTION OF COMPUTATION << INDICATES COMPUTATION CAN BE IN BOTH DIRECTIONS, DIRECTION TAKEN DEPENDENT ENERGY BALANCE LOGIC DIAGRAM ON AVAILABLE DATA. IF SUFFICIENT DATA WERE AVAILABLE CALCULATION WAS PERFORMED IN BOTH DIRECTIONS AND SERVED TO CROSS-CHECK RESULTS. CONTRIBUTION TO SPACE HEAT FIGURE C.1 page 7 transportation, electric power generation, etc.) in a village. The en- ergy balance data can be represented handily by a drawing showing the flow of energy from its source through its ultimate uses. Such a drawing is included in the Elfin Cove appendix. The objective of the energy balance task was to identify fuel type, quan- tities, and end uses in each community. Characteristically, the fuel types included fuel oi], wood, gasoline, and propane. The main end uses considered were space heating, water heating, electric power generation, transportation, and cooking. Energy usages for heating and power genera- tion were subdivided into residential use and commercial and government use. Gross energy input, net heat requirement, and electric power output were estimated. The following illustrates the procedures used in prepar- ing the energy balances. C.2.1 - Annual Fuel Consumption Fuel Oi] Wholesale purchase records for fuel oi] are the primary sources for data to determine the annual volume of fuel oi] consumed. This in- cluded electric utilities, schools, and commercial stores. Normally the annual oi] consumption of an electric utility was known; but, in those cases where unknown, it was estimated based on the annual electrical requirement assuming a particular fuel consumption rate based on diesel generator size. Those units rated less than 100 kW were assumed to produce 7 kWh/gal; 100 - 250 kW, 8 kWh/gal; units larger than 250 kW, 10 kWh/gal. The annual fuel oi] consumption of schools was either known or calculated using the Retherford! model for determining space heat requirements in bush schools, and the energy required for hot water heating was added. The annual sales volume of the commercial fuel oi] dealers was either known or esti- mated. Annual fuel oi] energy was computed by summing the annual volume of each source and multiplying by a standard energy content of 138,000 Btu/gallon. Gasoline Annual gasoline consumption was either obtained from the commercial dealers or estimated. An energy content of 125,000 Btu/gallon was used to compute total energy use. 1 R. W. Retherford Associates, Division of International Engineering, Anchorage, Alaska. page 8 Wood The annual consumption of wood was determined in a number of ways. In cases where estimates of the average annual consumption per resi- dent were considered good, this number was multiplied by the number of residences using wood (Since some residents burn both wood and oil, a percentage of the estimated village use of wood was used if appropriate.). In villages which used both wood and fuel oil for residence heating and for which the annual household consumption of fuel oi] was considered a good estimate, it was assumed that the net heating requirements would be the same for a similar house heated with wood. The number of homes heating with wood were then multiplied by the net heating requirement. An efficiency of 40 percent was used to determine the gross heat input. Heat content of wood was assumed to be 17 million Btu/cord. Propane Propane is normally used for cooking and hot water, but most of the energy actually goes into space heating. The annual usage of pro- pane was either supplied by the local commercial dealers or estimat- ed on a per household basis. In determining the usage of propane, an energy value of 19,500 Btu/pound, and a capacity of 100 pounds /bottle were used. C.2.2 - Electric Power Generation Electric power generation is almost exclusively by diesel generat- ors. Major consumers are schools, residences, government and com- mercial buildings. In some villages, there is no centralized dis- tribution network. Useful Energy - Waste Heat In cases where data for both the annual net generation in kWh and annual fuel consumption existed, both the useful energy and waste heat were calculated by taking both the net generation and fuel con- sumption and converting to equivalent Btu. The difference was con- sidered waste heat. Where one number was missing, it was calculated on the fuel consumption assumptions stated in Section C.2.1. In this way, both waste heat and useful energy could be determined. page 9 Useful Energy Useful energy was subdivided into electrical energy used by resi- dents and that used by schools, commercial buildings and government facilities. Consumption per household was normally based on the fraction of energy sold to the residential sector. Where this in- formation did not exist, it was estimated based on anticipated household appliances. Not all residents were on line in villages with a centralized system. For those residents who heated their water using electric heaters, an efficiency of 100 percent was assumed. Consumption per commercial/government building was determined in a similar fashion. C.2.3 - Commercial and Government Commercial and government fuel consumption consisted of both oil and wood, although oil was by far the most significant. Fuel oil used by the commercial and government sector, exclusive of schools, was normally estimated as a percent of the commercial sales. Water Heating Energy required for government and commercial hot water heating was considered for laundromat and water tank water heating only. Other government and commercial uses were considered minimal and neglect- ed. If the village had a laundromat, water heating requirements were determined assuming: two loads of clothes per week per house- hold, 20 gallons of hot water per load, a hot water temperature of 140°F, and an efficiency of 65 percent. If the laundromat had shower facilities, then it was assumed that residents took one shower each week, consuming 15 gallons per shower. Space Heating Gross space heating was calculated by taking the total energy input and subtracting hot water and other user energy consumptions. Gross space heat per building was then estimated based on the number of buildings and the relative requirements of government and commercial buildings as determined from the field observations. Using efficiencies of 40 percent for wood heating and oi! pot burn- ers, the net space heating requirements were computed. In buildings with gun-fired furnaces, an efficiency of 65 percent was used. In most circumstances, the net space heating requirements were also determined by taking the net residential space heating requirements and applying a conversion factor to determine commercial and govern- ment building requirements. Net space heating requirement was then divided by the gross space heating to yield an efficiency. page 10 C.2.4 - Residences Residences are generally heated with oi] or wood. In homes that use propane for cooking and heating hot water, most of the energy from combustion of the propane was assumed to contribute to the net space heat requirement and was, therefore, taken into account in the heat- ing fuel calculation. Water Heating Elfin Cove has an extensive residential running water system. Ac- cordingly, their hot water heating requirements is different from communities which do not have such systems. The following assumpt- ions were made to compute the water heating energy usage: daily per capita consumption of 10 gallons, hot water temperature of 140°F, and efficiencies of 65 percent for oil fired hot water heaters and 100 percent for electric hot water heaters. Space Heat Calculations for net space heat requirements were complicated by the fact that more than one house type might exist in a community, that some homes heated with both oi] and wood, that in some homes propane use contributed to space heat, and that village wood use had to be estimated since there are no bulk dealers of wood. Since wood was widely used, the equivalent percentage of villagers using wood was estimated. This accounted for the fact that some homes burned both wood and oil. One approach to estimating the an- nual average household consumption of wood was through personal in- terviews with the townspeople and comparison with other villages. If the net energy usage of an oi] consuming house could be accurate- ly estimated by assuming that the net energy usage of an oi] consum- ing and a wood burning house were the same, then an efficiency of 40 percent was applied to determine gross energy input. The total an- nual energy input was then computed by multiplying the household to- tals by the equivalent number of wood burning homes. Space heating requirements were determined by subtracting the water heating re- quirements from total energy usage on both a village and household scale. Residential consumption of fuel oil was estimated from total retail sales less a percentage for commercial sales. This volume was then distributed over the equivalent number of residences using oi] to determine household consumption. Net oil space heating usages were found using efficiences of 40 percent for oi] pot burners and 65 percent for gun-fired furnaces. page 11 In some cases the number of barrels of oi] consumed by a household was known. This was used to determine the gross energy usage of a household. If the village had running water, the gross energy for hot water heating was subtracted to determine the gross space heat usage. The net space heat requirement was computed using an appropriate efficiency. The gross energy usage of a household was multiplied by the number of residents using oil to determine the total residential consumption. C.3 - Energy Forecasts Energy use forecasts were developed based upon information provided by village residents regarding possible population and economic growth, com- parison of energy use and living standards between villages, and regional growth indicators. This information was combined to generate population growth projections, which were then used to project heat and power needs. Individual projections were prepared as follows: C.3.1 - Residential Electricity Forecast From the energy balance the present residential electrical demand and annual electrical energy consumption per household were determ- ined. Using the population and dwelling units forecast, residential village demand and energy use were determined. Annual residence percentage increases in demand and use were estimated. These in- creases varied depending on saturation of the community in terms of electrical appliance use. If households in a community were not connected to the utility sys- tem, it was assumed that within five years all households would be. Hookups were assumed to occur on linear basis annually. New housing units were assumed to be connected to the utility from the onset. C.3.2 - Commercial and Government Electricity Forecast Energy use and demands of existing schools were assumed to remain constant even though there may be slight increases in student pop- ulation. Energy use of commercial and government buildings was as- sumed constant. Forecasted new units were assumed to have the same electrical. consumption as existing buildings. page 12 C.3.3 - Thermal Energy Forecast Residences Net residential energy requirements per household were determined in the energy balance. The total community residence requirement was obtained by multiplying the forecasted number of units by the net residence requirement. New units were assumed to be more efficient and an appropriate adjustment factor was applied. Commercial and Government Net energy use of existing schools, commercial and government build- ings was assumed constant throughout the planning period. New units were assumed to have the same efficiency as existing units. C.4 - Energy Resource Evaluations Energy resources (wood, coal, water, wind, sun, etc.) were evaluated largely on a site by site basis. Inputs to these evaluations included previous resource assessments, study documents, residents' descriptions and estimates of nearby resources and observations. C.5 - Energy System Plan Development A minimum of three development plans for power production were to be pre- pared based upon the results of the activities described above. This was approached in two steps: (1) Screening and selection of appropriate technologies (2) Development of plans The screening activities were carried out through application of the fol- lowing screening methodology and criteria. C.5.1 - Screening Methodology and Criteria The screening methodology incorporates a three part evaluation of the various technologies as applied to Elfin Cove. The evaluation uses a weighted value system with ranking developed according to information available and requirements of the village under study. An overall score is determined for each candidate technology, using the following relationship based upon the ranking scores determined for each of three categories: page 13 Score = (A+B) XC (0 to 100) ue Where A = total Technical Factor score B C total Cost Factor score combined Resource Availability score Technical Factors Technical factors can be grouped into three sub-categories - reliability, construction requirements and environmental impacts. Cost Factors Cost factors can be separated into initial costs for instal- lation of the system (capital cost), recurring costs of owner- ship and operation (operation, maintenance, and annual expen- ses), and fuel costs. Resource Availability The selection of any particular technology to supply heat or power is completely dependent upon the availability of sup- porting resources. Included in this category are the fuel/energy source, the operating staff, technical and commun- ity support services, transportation network and communica- tions systems required. A relative evaluation scale is applied to each subcategory for each technology. Values are assigned based upon the findings documented in the technology assessments (contained in Section E) and site spe- cific determinations. The evaluation scales are based upon the following considerations: Technical Factors Reliability Reliability refers to the level of confidence a system provides to the customer that his needs will be met at all times. Reliability of a given system is affected by operating conditions, maintenance policies and completeness of the initial installation, and individ- ual component system reliabilities. Performance capability and design maturity are additional factors associated with components (particularly the generating plant) con- tributing to system reliability. page 14 Equipment capacity and performance also affect reliability. An el- ectric generation system of inadequate capacity or incapable of re- sponding adequately to a load change will (if properly protected) shut itself down whenever demand exceeds capability. Undersized heating systems will not heat a home adequately in severe condi- tions. In both cases the customer has an unreliable system. Availability A major factor in electric system reliability is equipment availbil- ity. Availability refers to the percent of maximum possible time that a system is capable of operating as expected. Equipment or system failures of a hardware nature are commonly referred to as forced outages, while scheduled maintenance is a planned outage. Both reduce availability. Availability and outage data are diffi- cult to obtain for most Alaskan village applications, primarily be- cause the required data are not well documented. Information from other parts of the U.S. is of questionable applicability given the particular difficulties of Alaskan operations. Building heating systems are usually of very simple design so as to achieve very high availability. Problems are readily detected and generally very easy to correct. Thus availability of common types of heating systems is generally not a great concern. The Importance of Design Maturity Forced outages due to mechanical failure typically are more frequent and longer in duration for new equipment designs with limited opera- tional history. Initial design errors often only surface once the design reaches the point of commercial installation and service. Replacement with new but inadequately designed parts rarely solves such problems, necessitating redesign and retrofit by either the manufacturer or the customer. This may entail an extended outage for a relatively simple redesign, or a number of part replacements until a major redesign can reach the point where proper parts or as- semblies can be built, shipped and installed. Thus, design matur- ity, as evidenced by number of units in operation and hours or years of operation since design/redesign, is of significant importance to predicting reliability. System Complexity As a system becomes more complex (i.e., increasing numbers of moving parts and/or less modular construction), the possibility of failure also tends to increase. This can be offset by greater redundancy and quality control, but only when accompanied by increased initial costs for production and installation. More elaborate maintenance procedures are often a secondary result. page 15 Alaskan bush conditions, for the most part, are not conducive to us- ing highly skilled maintenance personnel to perform complex proced- ures with high levels of support equipment. Small villages are generally remote - largely accessable on a year-round basis only by small planes as permitted by weather. Although on-site personnel may be given extensive training, their newly acquired skills often depend upon availability and use of extensive support equipment. Such requirements are expensive and, therefore, less desirable un- less the expense is a minor portion of overall costs. Ideally, equipment selected for use should need an absolute minimum of daily maintenance, and should require only very occasional main- tenance on a scheduled basis by highly skilled service technicians. Support Requirements A major attraction of diesel systems is the limited training requir- ed for operation and regular maintenance procedures. Service sup- port does, however, require spare parts inventories, machine shop facilities, and trained mechanics and electricians to perform re- pairs, replacements and overhauls on equipment. Unless located close by, this support structure also requires a transportation sys- tem capable of delivering the service personnel, parts and tools re- quired on short notice. Spare parts inventories for any given technology can become a major investment as complexity, physical size and uniqueness of the selected equipment increases. Large investments in spare parts are undesirable for either the customer or the equipment supplier. In- vestment required is totally a function of system complexity, desir- ed reliability, technological maturity, and operating policies. Reliability Characteristics The performance aspect of reliability is for the most part only ap- plicable to electric generator technologies. Heating systems gener - ally work either in a full on/full off mode, or are manually adjust- ed by the user (i.e., wood stove). Electric generator system load response characteristics are of interest here. Ability to accept sudden changes in customer loads affects the selection of unit capacity for small systems. Ranking Range: 0-5 points Construction Requirements Construction in remote areas of Alaska involves major limitations on availability of manpower, equipment transport, availability and page 16 usefulness of large earth moving and erection equipment, load bear- ing capability of soils, weather conditions and support services. Diesel engine systems require a minimum of construction labor to in- stall, minimal excavations, foundations and protective structures, and minimal lifting equipment to put the equipment in place. There- fore, system generating capability can be installed within a matter of weeks, or less, and be ready to supply energy to the distribution system. Construction skill requirements and availability, field housing, transportation for manpower materials and equipment needed, geotech- nical requirements and construction season must be considered for the various approaches to providing electric power or elaborate methods of building heating. Ranking Range: 0-2 points Environmental Impacts Environmental impacts can be categorized according to the following areas: a. animal habitats displacement b. land use c. air emissions d. noise e. water quality and use f. visual impact g. electromagnetic field interferences h. solid and liquid waste disposal Ideally, power generation and heating should have minimum impact on any of the above areas. In reality, each technology has impacts of various severity levels in each area. Diesel generating systems presently in use in the remote villages have varying impacts according to location. However, diesel charac- teristics can be generalized to some extent to provide a comparison baseline. Most systems are housed in modest buildings adjacent to the commun- ity, thus displacing few, if any, wild animal habitats and contrib- uting little to the requirements for land. Air emissions are pro- duced as a result of the combustion process, and significant noise is produced and emitted to the surroundings. Water use is minimal, as the cooling systems are sealed and rarely drained. Visual impact is limited to the area of the protective structure - the stack plume, fuel oil drums or storage tanks, and the building itself (separate from the distribution cables which would exist with any production methods). Electromagnetic field interferences are page 17 minimal unless a defect exists in the generating system. Waste dis- posal is primarily limited to waste oil, parts boxes and cartons, and scrap parts, and may or may not be confined to the area of the powerhouse. Ranking Range: 0-2 points Maximum Total Ranking Points - Technical Factors: 9 | Cost Factors Electric users rates are a direct function of both initial cost and annual costs of operation. Selection of the equipment to be used is generally made on the basis of minimum expected cost based upon a selected group of factors. Whereas private citizens in some in- stances exclude initial cost (often the case with heating systems), prudent decisions can be only made when initial cost, system life and operating costs are all examined. Initial Investment Initial costs include the costs of the basic equipment, shipping, erection and startup. These are subject to the variability of field conditions and labor availability in the Alaskan bush areas. In- itial costs used must, therefore, be risk adjusted. Normal practice for installation cost estimates is to provide a contingency fund based upon the perceived cost uncertainty range. equipment shipping erection support facilities personnel support during construction mobilization/demobilization AnPwWrrH Ranking Range: 0-4 points Fixed Annual Costs Fixed annual costs include (at a minimum) the annual payments of principal and interest to cover the cost of the initial installa- tion. These payments are generally determined by the expected life- time of the equipment. Initial investment and operating lifetime can generally be predicted for mature technologies. As annual fixed costs are highly dependent upon operating life expectancy, unexpec- tedly short life can result in serious problems in financing re- placement equipment and in providing sufficient revenues to pay off creditors who financed the initial installation. page 18 Operating Costs Operating costs can be subject to considerable uncertainty, with a resulting effect on user rates. If relatively small in proportion to fixed annual costs (as in the case of hydroelectric or wind power), operating cost uncertainty has minimal effect. Operating costs for diesel engine systems tend to represent a large proportion of costs for small units, but their impact diminishes as unit size increases. Rural Alaskan conditions also tend to increase annual operating costs, because of the difficulties of obtaining service. Operation, maintenance, fixed annual costs include the following: operating labor supplies and materials replacement parts and maintenance labor maintenance support services replacement operator training insurance depreciation debt service general administrative WONDOHPWNHr-H Ranking Range 0-5 points Fuel Costs Fuel costs and use as defined by system efficiency, or costs as- sociated with gathering and transport of energy source. Ranking Range 0-3 points [_ Maximum Total Ranking Points--Cost Factors: II | Resource Availablity Factors No technology is applicable to a situation if its resource require- ments are unavailable. For example, a geothermal power plant cannot be considered if no source of geothermal heat exists in the region. Consequently, resource availability is a critical parameter separate from the technical and cost considerations. Both natural and human resource needs must be considered. These include energy sources (fuels, etc.), skilled labor needs and availability, and the exist- ence of a support structure for construction supplies, equipment and human services (schools, medical facilities, etc.) and operating support (communications, roads, etc.). Natural resources required for some technologies either do not exist at site or are available in various quantities. Wood based tech- nologies, for example, are subject to various levels of resource page 19 availability. Sufficient tree stock may exist to allow heating of all homes for 100, 50, 20, 11 or 2 years for example. The same con- siderations apply to local coal deposits and to wind resources as represented by average windspeed. Technologies that are otherwise attractive are useless if adequate supplies of the basic energy source do not exist. Availability also applies to imported fuels such as diesel oil, propane and gasoline, but is generally a more direct function of acceptable purchase price levels. The resources associated with social and economic development can be provided if nonexistent at present, but success of an installation is relatively assured if the required skills and services are readi- ly available. Natural Resources Ranking Range: 0-9 points Economic and Social Resources Ranking Range: 0-2 points A set of criteria for determining point scores has been developed for each of the above categories, as presented on the following pages. [Maximum Total Ranking Points--Resource Availability Factors: 1]j page 20 RANKING SCALE CRITERIA Technical Factors Reliability 0-5 points 5 points 4 points 3 points 2 points 1 point 0 points mature technology, highly reliable, service sup- port readily available, parts kept in stock. mature technology, generally reliable (occasion- al outages), service support readily available. mature technology, generally reliable, weak service support system (delays foreseen for many types of parts or service). commercial technology; intermittent availability or poor service support (outages can be expected to last weeks or months). developing technology expected to be commercial within 5 years; intermittent availability and poor service. immature technology. Construction Requirements 0 - 2 points 2 points 1 point 0 points minimal site preparation, foundations, struc- tures and construction time required (less than 1 year). significant site construction required - founda- tions, erection of structures; construction time 1-5 years. extensive on site construction required, con- struction period 5 years or more. Environmental Impact 0 - 2 points 2 points 1 point 0 points negligible environmental impact on or near site. a) significant impact on air or water quality, or b) significant waste quantities for disposal, or c) significant land use alteration. significant impacts in at least 2 of the above categories. Cost Factors page 21 Investment Cost 0 - 4 points 4 points 3 points 2 points 1 point 0 points electric - cost per kilowatt of expected reli- able capacity or capacity useable in the next ten years is between $500 and $1,000 heating - initial cost per resident is less than $1,000. electric - cost per kilowatt is between $1,000 - heating - initial cost is $1,000 to $2,000 per residence. electric - cost per kilowatt is between $3,000 - $5,000. heating - initial cost is $2,000 to $3,000 per residence. electric - cost per kilowatt is between $5,000 and $10,000 heating - initial cost is $3,000 to $5,000 per res idence. electric - cost exceeds $10,000 per kilowatt of capacity. heating - cost exceeds $5,000 per residence. Operational Cost 0 - 4 points 4 points 3 points 2 points 1 point 0 points annual operating and maintenance labor expenses, incremental overhead expenses and replacement parts and supplies do not exceed $5,000/GWh pro- duced. same as above except $20,000/GWh produced. annual labor costs, incremental overhead, and parts and supplies do not exceed $50,000/GWh produced. annual costs (as above) do not exceed $100 ,000/GWh produced. annual costs exceed $100,000/GWh produced for heating; : 1 GWh = 3.4 X 109 Btu delivered. page 22 Fuel Costs 0 - 3 points 3 points 2 points 1 point 0 points Fuel cost is governed by fuel conversion effici- ency. Annual costs for labor, equipment replacement and depreciation, and local transport expenses are a maximum of 25 percent of equivalent oi] fuel price in present $; price is independent of world market. costs of labor to obtain fuel, equipment re- placement and depreciation and expenses of transport and preparation are a maximum of 50 percent of oil fuel price with minimal sensitiv- ity to outside market price forces. costs of obtaining energy source and expenses of transport and preparation are approximately equal to oil fuel, at present, or are 50 percent or more of oil fuel costs and tied to oil fuel escalation (diesel base case). costs are equal to or exceed oi] fuel price, es- calate at approximately the same rate due to high interdependence, or system is less effic- jent than existing oil fired design. Resource Availability Natural Resources 0 - 9 points 9 points 7 points 5 points 3 points 1 point 0 points extensive resources readily available to the village (0-5 miles). extensive resources readily available, but may require importation by air or barge, or are located 10 to 20 miles away by ground transport. sufficient resources available in region or from outside to maintain operations for 20 years or to support large portion of required capacity. modest resources available (5-10 years supply for less than 50 percent of needed capacity), or resources available on intermittent basis. minimal resources available (1-5 years supply for less than 50 percent capacity). no resources available. page 23 Socioeconomic Resources 0 - 2 points 2 points labor force with required skills exists in area; existing communiciations, transportation, safe- ty, health and educational systems are adequate to accommodate needs associated with the tech- nology. 1 point labor force, communications, health, transporta- tion safety and educational systems available in village. 0 points inadequte social/economic structure exists to support development. An example of the use of these criteria is provided in Section F of this report. C.5.2 - Development of Plans Heating options were examined and technologies considered appropriate were selected and recommended for consideration. Potential savings have been identified on a generalized basis only, as actual heating loads of individual buildings vary greatly even within a community. The planning activities therefore concentrated on identifying any al- ternatives suitable for each village. Electric power generation/supply plans were developed for each vil- lage. Wholesale overhaul of the existing system was not an approach used for any of the communities studied. The existing system was ex- amined in light of load projections to identify optimum timing of in- stallations using alternate technology. System capacity requirements were determined based upon having adequate reserve capacity to cover peak load in the event that the largest unit went out of service in any given year. The resulting plans are described in later sections. C.6 - Cost Estimation Cost estimates for each plan were based upon information from various sources: oooo°o manufacturers . published reports vendors in-house data transportation rate schedules Costs were adjusted for site specific conditions. page 24 C.7 - Economic Evaluation Economic evaluation of development plans was performed in accordance with the standard procedures of the Alaska Power Authority for reconnaissance and feasibility studies performed in fiscal year 1982. These procedures essentially require a simplified present worth of minimum revenue re- quirements approach based upon a real financial discount rate of 3.5 percent and real oil escalation at 2.5 percent. The techniques used produce annual or average costs of energy which are not comparable to any other costs for energy unless also calculated by the same methods. Actual costs paid by community residents will, in gen- eral, be higher than the rates derived for the analysis, because of the following: 1. Consumers pay the costs associated with actual operation of a utility in an economy experiencing significant inflation. The engineering evaluations performed are based upon long term cost evaluation prin- ciples which recognize the impact of inflation. Engineering evalua- tions are, therefore, based on modified long term costs, to insure that the system selected will minimize the customers cost. The rates customers presently pay for the use of the equipment or methods being studied will be similar at present, but in all likelihood higher than shown on the tables of this report. 2. The analysis techniques ‘ignore costs which are common to all possible methods of providing energy. In the case of electricity, these in- clude the cost of village distribution systems (where they already exist), metering, residential service, billing and administrative costs and utility general staff. The customer's bill does include these costs on a pro-rated basis. Establishment of proper rates for these common items comes under the jurisdiction of the Alaska Public Utilities Commission and is not within the scope of these studies. These items also increase the rate actually paid by the customer in comparison to the values tabulated in this report. The costs derived in this report are directly comparable only to other costs contained in the report or to costs derived for other villages in Fiscal Year 1983 Reconnaissance Studies. page 25 A standard economic life is assigned to each different alternative. These lifetimes are as follows: Gasification Equipment ............ 10 years Diesel Units <300 kW. ........2.2.24.- 10 years Waste Heat Recovery Equipment <5 MW ..... 10 years Photovoltaic Systems, Wind Turbines, Organic Rankine Cycle Turbines, Geothermal Turbines. . 15 years Diesel Units >300 kW. ..... 2... 2. eee 20 years Waste Heat Recovery Equipment >5 MW. ..... 20 years Gas’ Turbines «sss se ss ws ew ew we ss 6s 20 years Coal- and Wood-Fired Steam Turbines <10 MW . . 20 years Solid Dielectric Power Cables. ........ 20 years Combined Cycle Turbines (Steam Turbine End). . 30 years Coal- and Wood-Fired Steam Turbines >10 MW. . 30 years Oil Filled Power Cables. .......... . 30 years Transmission Lines With Wood Poles. .... - 30 years Transmission Lines With Steel Towers ..... 40 years Hydroelectric Plants (see note 1). .... . . 50 years Economic projections for all alternatives in each village will be extend- ed to the alternative having the longest life. For instance, the econom- ic projections of a village having hydropower and diesel generation al- ternatives will be carried to 50 years in both alternatives. Similarly, if an alternative has a subsystem coming on line in later years which ex- tends the economic life of the entire system, all alternatives will be carried to that economic life. Note 1. An economic lifetime (useful life) of 50 years has been assigned to hydroelectric plants; their financing term is only 35 years. Page 26 D_- SUMMARY D.1 - General Elfin Cove was visited to determine on a first-hand basis conditions re- garding energy use and village development. The results indicate that the problem of high energy costs in the villages cannot be entirely solv- ed by simple substitutions of technology. Improvements are possible which can produce significant cost reductions. Savings will primarily be seen to develop over many years. Major reductions in the quantity of fuel used to generate electric power is possible through the use of a village-wide electric power system. Careful system planning on a villagewide basis, combined with coordinated operation of generators can noticeably improve operating efficiency and reduce costs. Likewise, it becomes imperative that each generator owner examine their maintenance and operation procedures to insure that an ef- fective, continual preventive maintenance program is in place. Short of such a program, premature equipment failure and major replacement costs can be expected. Diesel engine generators will remain the primary source of electric power in nearly all village-wide systems through the year 2000. Elfin Cove has been identified as strong candidate site for a micro-hydro project. Such a renewable technology can supplement diesel generation, reducing oil fuel requirements. In some isolated cases, it is possible that hydroelectric power, a renewable resource, could completely eliminate dependency on diesel generation except for emergency backup purposes, though this is not thought to be the case in Elfin Cove. Passive solar heating home design techniques appear worth considering for southeastern villages, although normal weather conditions limit the re- sults which can be expected. General improvements in the design and con- struction of building insulation systems can most easily provide signifi- cant reductions in energy consumption. Photovoltaic systems do not ap- pear attractive for residential power, but will continue to find special- ized application. 7 page 27 Elfin Cove has sufficient hydroelectric and perhaps wind energy potential to warrant further study (Recommendations 3 and 4). Wood, which is already in widespread use in Elfin Cove, could help to further reduce dependence on "imported" oil fuels if its use were increased. Energy conservation techniques appear attractive in the case of Elfin Cove. Conservation requires a small investment in training as to simple heat conserving improvements for rural homes. Lifestyles should not be noticeably altered as a result. Elfin Cove is one of the few villages in which waste heat recovery from diesels to heat community structures does not appear to be attractive. This is due to the village's very small size and the extremes to which its population changes with the seasons. Fuel conversion technologies (coal, wood and biomass gasification) do not appear sufficiently developed for rural application at this time. Wood gasification may, however, find application in the next decade in those locations with good wood resources. D.2 - Specific Recommendations for Elfin Cove The results of this study show that the best opportunity for providing the people of Elfin Cove with an economical electricity supply would be the development of a small hydroelectric plant in the village. There are a number of ways in which this could be carried out, although this report has concentrated on a hydro plant on “Roy's Creek." Other attractive op- tions include the diversion of some of the flow now in "Joe's Creek" into "Roy's Creek"; the raising of the elevation of the "Lilly Ponds" about 5 feet to provide some energy storage capacity, with a diversion over to "Roy's Creek"; and the direct use of the water from the "Lilly Ponds." Detailed study of a plant in Roy's Creek and the diversion of Joe's Creek would seem to be the most productive approaches to be taken in the future. The development of this hydro plant would require the construction of a village-wide power distribution system. At the low levels of power de- mand which we believe will be used in Elfin Cove, this distribution could probably be accomplished at 480 Volts. Throughout most of the village, which is connected by boardwalks, an underground-type cable could be run under the boardwalk, protected by a conduit where necessary. In the areas where there is no boardwalk, the power line could be strung over- head, using some of the many trees in the areas as utility poles. Re- portedly, this approach has been taken in a few other areas of the state with no problems. It is not likely that a hydro plant using Roy's Creek (even with a di- version from Joe's Creek) would supply all of the energy needed by the village. This being the case, it would be necessary to include a diesel page 28 generator to provide power when the hydro plant could not meet the power requriements of the village. A key aspect of the development of any power system in Elfin Cove is the utilization of locally available labor. More than in any of the other 20 villages studied by Acres under this contract, the residents of Elfin Cove expressed an interest in helping to build, operate, and maintain any hydro facility constructed there. It is the opinion of Acres' staff that the skills already exist in the village to successfully operate a smal] hydroelectric plant. Another key to the plant's success is the use of very simple design techniques. It would not be appropriate to load this project with all sorts of “bells and whistles." The more basic the equipment provided, the better the chances it will work as intended. A village-wide power system without the hydro plant would be an improve- ment (from an economic standpoint) over the existing situation in Elfin Cove. Individual homeowners must buy and operate their own generator sets (usually diesel) if they want to have electricity. These small gen- erators are very inefficient and represent an "“overbuild" in terms of generator capacity installed throughout the village versus the total power requirements of the village. Doing nothing in Elfin Cove would be the least economical approach to future energy supplies in the village for the reasons mentioned above. page 29 D.3 - Further Recommendations The results of this study indicate that consumer energy bills can be re- duced over the coming decades in Elfin Cove. The village will benefit from reduction of infiltration losses and selective improvements in building insulation. Simply put, this means gaps should be plugged ar- ound doors and windows, at joints in walls, and in many of the new houses within the under floor structure. This will produce significant energy savings in the homes occupied on a year-round basis. The heating energy used in a home could also be cut significantly in many villages through the use of more efficient wood or oil stoves. These need not be expensive. For example, easy to use kits are available for conversion of oil] drums to high efficiency wood stoves. Recommendation No. 1 - Conservation Information regarding simple conservation improvements should be provided to residents, preferably through a program of energy use "workshops" led by people from the region trained to use and teach these methods. Such a program is recommended as the simplest way to provide significant savings in village energy costs. Recommendation No. 2 - Make Specialized Services and Information Available to Residents Establish a “consultant pool" of consulting firms or individual special- ists which are available to the regional corporations or villages on an as needed basis. People with specialized knowledge could be made avail- able to study and provide workable solutions to specific energy problems common to a significant number of residences or several villages in a re- gion. Such a group could work very closely with the regional corporation and the native energy specialists trained to carry out the recommended conservation program. Recommendation No. 3 - Evaluate Local Hydro Potential Proceed with more: detailed hydroelectric feasibility studies at Elfin Cove. The drainages adjacent to the village represent an opprotunity for the development of a micro-hydro plant. Early indications suggest that there will be times when substantially more power will be available than is needed. There are not envisioned to be any environmental impacts from such a project since there are no fish stocks of any sort in any of the water sources around the villages. The implications of the proximity of Tongass National Forest land in the area should be investigated. page 30 Recommendation No. 4 - Define Wind Resources More Completely Establish appropriate wind anemometry stations at some exposed ridgetop near Elfin Cove. The uncertainty of the values presented in the "Wind Energy Atlas" lead the authors of this report to believe that a wind re- source could exist in the area (due to its proximity to the Guif of Alaska). The terrain in the area is so rugged that measurements taken at weather stations remote from the village would not be representative of conditions at Elfin Cove. Recommendation No. 6 - Periodic Review Elfin Cove should continually monitor the development of its economy and population in light of these studies. More rapid development than antic- ipated can increase the number of options open to many villages for re- duction of costs. Energy costs are high in Elfin Cove when compared to the amount of money spent by residents of Anchorage. Heating is the major fuel use, and costs can be reduced by cutting down on heating needs and more efficient use of fuels. Wood should be used whenever possible for heating. Elec- tric power costs are "high" (and will continue to be so) primarily be- cause the village's needs can only support small inefficient systems. Proper operation and maintenance and good system planning are key to holding down costs in any electric utility system, and should receive continuous attention for the village's systems. page E - TECHNOLOGY PROFILES INTRODUCTION The technology profiles which follow are an attempt to provide a consist- ent, appropriate, data base from which to draw when preparing alternative plans for the individual villages. These technology profiles contain gen- eral information on different types of power producing technologies and at- tempt to assess their general applicability to Alaskan uses. Data on sit- ing requirements, costs, and efficiencies are made available on a consist- ent basis for use later in alternative plan development. Much of the data contained in this section was taken from a report prepared in 1981 by the Robert W. Retherford Division of International Engineering Company+, as suggested by the Alaska Power Authority. Their data was reviewed for its suitability for this report and revised where appropriate. Cost estimates developed in that work were updated. Costs in this report are expressed in estimated January 1983 dollars. Although at least several data sources are available for each technology, the data generally is quite variable (often based on incompatible assump- tions) and, perhaps more important, does not often apply to systems suited for Alaskan use. Data discrepancies for the so-called alternative energy technologies are also strongly influenced by the simple lack of experience in constructing and operating facilities utilizing these technologies. EXPLANATORY NOTES 1. Factors that cause differences in electrical generating plant capital costs per kW include: project scope regulatory requirements local cost variations plant size single versus multiple unit plants construction time interest rates 1 International Engineering Company Inc., "Reconnaissance Study of En- ergy Requirements and Alternatives for Buckland, Chathbaluk, Crooked Creek, Hughes, Koyukuk, Nikolei, Red Devil, Russian Mission, Sheldon Point Sleetmute, Stony River, Takotna and Telida," 1981. 31 2. page The availability factor is used as a measure of reliability and is the percentage of time over a specified period (typically one year) that the power plant was available to generate electricity. Credit for availability is not given if the plant is shut down for any reason. Net Energy as used here is typically referred to as the “heat rate" in the case of electric generation and is expressed as the ratio of Btu in to kWh out in this case. For direct heat application cases, this ratio is Btu in to Btu out. 32 page 33 E.1 - STEAM-ELECTRIC TECHNOLOGIES —.1.1 - Direct Fired Coal for Electrical Generation E.1.1.1 - General Description Thermodynamic and engineering processes involved: Coal is ground to readily combustible size and mechanically loaded into a boiler furnace where it is burned to provide heat to convert incoming water to steam. The steam is then expanded in a turbine which drives a generator to produce electricity. Figure E1.1-1 shows a simplified steam power cycle. Current and future availability Steam plants account for the majority of electrical generation in the United States today. Although steam plants can accommodate a wide range of loads, U.S. economies of scale indicate that the cost per unit increases sharply in sizes below about 50 MWe. It should be noted that European coal-steam generation units are employed in the less-than-10 MWe range. E.1.1.2 - Performance Characteristics Energy output Quality - temperature form Electricity Quantity Unit sizes available up to 1,300 MW. Sizes appropriate to Alaska are typically 5-50 MWe; 1 MWe (1,000 kWe). Dynamics - daily, seasonal, annual Coal-fired steam plants are typically used to generate power on a continuous basis at nearly constant output without respect to time of year. page 35 Availability Factor National statistics for investor-owned utility plants in the 60 to 89 MW size range (the smallest size documented) show typical unit availability of 90 percent. Availability tends to drop as unit size increases. Back-up required to allow both planned and unplanned maintenance during unavailable periods. Storage requirements Typical fuel in storage for major coal-fired plants is sufficient supply for 90 days of operation. For village areas, up to 12 months worth of coal storage may be required to guarantee continuous supply irrespective of weather. Thermodynamic efficiency Up to 35 percent for large units; much lower efficiency expected for 10 MW scale units Net Energy 10,000 - 17,500 Btu input per kWh of output E.1.1.3 - Costs Capital Investment for 1 to 10 MW plant Estimated range of $3,200 to $5,500/kW, excluding transmission line. Cost highly variable with plant capacity and location. Operation 50-100 $/kW/yr for small plants (less than 10,000 kW) such as at Kotzebue Fuel cost for $65/ton, 6,800 Btu/Ib, and 17,500 Btu/kWh works out to 8.4¢/kWh (Kotzebue using Chicago Creek coal). Maintenance and replacement 2.5 percent of initial investment per year in real dollars for maintenance 2.1 percent of initial investment per year for replacement (sinking fund @ 3 percent for 30 years). Economies of scale page 36 Economies of scale favor larger scale plants than normally considered for Alaska, particularly with respect to coal handling facilities. (New plants in the lower 48 are typically of 1,000 MWe size with two 500 MW units.) Full-time operator requirements also favor large plants to reduce costs per kilowatt hour generated. E.1.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height Coal plants require space for storage of fuel. Cooling water is not mandatory for Alaska conditions as air cooled condensers can be used with small plants. If the plant is sited at a mine, fuel transport problems are reduced; storage of a month's fuel use may be adequate. Resource needs Renewab le NA Non-renewab le Typical Alaskan coal ranges from 6,500 to 8,000 Btu per pound. Limestone or dolomite will also be required if a scrubber system is installed. Water may be required for condenser cooling and for the scrubber system if a wet type design. Construction and operating employment by skill Requires highly skilled construction and operating personnel. Environmental residuals Solid wastes: include slag, bottom ash, scrubber sludge. Gaseous wastes: NOy, SOx. Current environmental regulations regarding sulfur dioxide emissions from conventional coal-steam plants require abatement processes which limit emission quantities from units with energy inputs equal to or exceeding 250 million Btu per hour (roughly equivalent to a 15 to 20 MW unit). Coal-fired plants emit the following, as yet unregulated, atmospheric pollutants: toxic and carcinogenic trace elements, radionuclides, and organic and metal-organic compounds. Other Eal.2Z page 37 considerations include impact of mining, transport and storage of fuel, and coal pile run off. Health or Safety Aspects See above. Additionally, typical Alaskan coal is quite prone to spontaneous combustion. Regular turnover of the stockpiled coal by bulldozers would be needed to prevent this problem at locations with extensive storage. Coal allowed to remain undistrubed for only a matter of a few days can catch on fire. E.1.1.5 - Summary and Critical Discussion Cost per million Btu or KWh Smal] Alaskan plants will generate at costs of 10-15¢/kWh at 50 percent capacity factor with $65/ton coal. Use of $130/ton coal increases costs by 5 to 9 ¢/KWh depending upon unit efficiency. Resources, requirements, environmental residuals per million Btu or kWh. For coal at 6,800 Btu per pound and plant at 17,500 Btu/kWh, 2.6 pounds of coal are needed per kWh. NOx emissions are about 0.15 lbs/million Btu. SOx emissions are about 0.067 Ibs/million Btu (with precipitator on stack). Particulate emissions are about 0.006 Ibs/million Btu. Solid wastes are about 10 percent of fuel quantity burned. Critical discussion of the technology, its reliability and its avai lability. In general, the conventional boiler-fired steam turbine system is the most economic and technologically developed system available to the power industry. Available coal-fired boiler sizes limit minimum plant size to perhaps 5 MWe, however. Lead time is significantly longer than for diesel or gas turbine installation. - Wood-Fired Steam for Electrical Generation E.1.2.1 - General Description Thermodynamic and engineering processes involved Wood can be directly fired in traveling grate or stoker type steam boilers to provide steam for a conventional steam turbine cycle. Boilers designed for wood are significantly larger in size than an equivalent coal-fired boiler, and much larger than page 38 an oil-fired unit. Figure El1.2-1 shows a wood-steam plant flow diagram. Current and future availability Existing commercial systems are roughly in the 1-50 MW range. A number of U.S. manufacturers produce wood-fired boiler designs suitable for generating electricity in the 250-1,000 kW range. E£.1.2.2 - Performance Characteristics Energy output Quality - temperature, form Electricity Quantity Plant sizes vary from 0.5 to 50 MW, although most economies of operation suggest a minimum size plant of 5 MW Dynamics - daily, seasonal, annual Future supplies can be adversely impacted by: economic competition, distance of supplies, and needs for sustained forest yield levels. Reliability Availability factor Availability expected to be similar to a coal-fired plant; 80 to 90 percent. Storage requirements As for a coal plant, ninety days of fuel is typically stored; up to 9 months storage is required if climate only permits a few months of harvesting and transportation. Thermodynamic efficiency up to 21 percent Net energy 16,000 - 30,000 Btu/kWh wooD & TRANSPO WooD NSPORT WASTE STACK EMISSION CONTROL TURBINE CONVEY,| cs opage LCONVEY,| BolLeR PIPING PREPARATION GENERATOR WATER | CONDENSER TRASH ASH REMOVAL HANDLING COOLING FLUID WOOD FIRED STEAM POWER PLANT FLOW DIAGRAM FIGURE 6€ abea page 40 Esl32.3 = Costs Capital $1 ,600/kW (Kake 1500 kW) $3 ,000/kW (Angoon 400 kW) Assembly and installation $1,600/kW (Kake 1500 kW) $3 ,000/kW (Angoon 400 kW) Operation $600 ,000/yr (Kake 1500 kW) + 10 percent of fuel costs $470 ,000/yr (Angoon 400 kW) Maintenance and replacement 2.5 percent of investment per year for maintenance (Kake 1500 maintenance) 3.7 percent of investment per year for replacement (sinking fund at 3 percent for 20 years) Economies of scale Economies of scale favor plants in the 15-50 MW range based on fuel handling and operator requirements. E.1.2.4 - Special Requirements and Impacts Siting - directional aspect, land, height Wood storage area is the major land use. Air condensing can eliminate cooling water requirements. Resource needs Renewab le Typical wood heating values are 17,000,000 Btu/cord when dry; 12,000,000 Btu/cord wet. This translates to an energy production rate of about 1,100 kWh/cord of dry wood. At this rate, the village of Galena, which presently consumes 1,100,000 kWh of electricity annually, would require 1,000 cords of dry wood each year if it were to generate all of its electricity with a wood-fired steam plant. In the Galena area, this would raping that about 33 acres of forest be harvested each year.+ Considering the slow —_——— 1 Reid, Collins Alaska Inc., see Main Report, Bibliography Reference 20. page 41 growth of timber in interior Alaska, it can be seen that over the normal 30-year life of a wood-fired steam plant, about 1,000 acres (1-1/2 square miles) would be affected. Non-renewab le NA Construction and operating employment by skill Requires highly skilled construction and operation personnel. Environmental residuals Solids: Ash particulates Aine SOx, NOx Impacts of harvesting Considerations include impact of cutting, transport and storage of fuel, and wood pile run off. Risk of spontaneous combustion Injury rate of wood cutting £.1.2.5 - Summary and Critical Discussion Cost per million Btu or kWh Resources , requirements, environmental residuals per million Btu or KWh Per above, at least two pounds of dry wood are required per kWh; three to four pounds/kWh is more probable. NOx emissions are about 0.25-1.18 lbs/million Btu SO, emissions are about 0.07-0.18 lbs/million Btu Particulate emissions are about 0.02 lbs/million Btu Residual ash from wood firing is not classified as a hazardous waste; firing wood waste actually decreases the amount of solid waste. Critical discussion of the technology, its reliability and its avai lability r Although dry wood (at about 8,000 Btu/pound) has about the same potential heat content as much of Alaska's coal, most wood is sufficiently moist to reduce this heat value by 40 to 50 percent. In addition to the moisture content, the relative volume-to- ~ weight ratio of wood is disadvantageous as compared to coal, with consequent increased material handling requirements. Also, as compared to coal, the fuel gathering and transportation processes result in the expenditure of significantly greater amounts of energy. Wood, a relatively clean burning fuel, is more suitable for smaller steam power plant than is coal. page 42 E.1.3 - Geothermal - Electric (Flashed Steam) E.1.3.1 - General Description Thermodynamic and engineering processes involved Geothermal power production has been proposed or demonstrated for areas with natural steam, hot water or dry hot rock resources. The well-known Geysers facility in California involves use of natural steams. A facility at Heber, California is demonstrating the use of hot water throttled to produce steam by flash vaporization. Other methods involve extraction of heat from geothermal water using binary cycles. Geothermal electric generation in Alaska would be by the flashed steam or binary processes. Binary conversion technology is discussed generically in another profile; the flashed steam technology is profiled here as shown schematically in Figure E 1.3-1. The flashed steam process applies to liquid dominated geothermal reservoirs such as those thought to exist in Alaska. Hot liquids are brought to the surface and partially converted to steam in flash vessels where the fluids undergo pressure reduction. The separated steam component is used to power a steam turbine-generator and spent and separated fluids are reinjected into the earth to minimize potential subsidence prob lems. Current and future availability (Flashed Steam) Not currently in commercial practice in the United States, but over 140 MW in operation in foreign countries. U.S. environmental restrictions are much more severe, in general. £.1.3.2 - Performance Characteristics Energy output Quality - temperature form Electricity Quantity Economic California plant units are in the range of 35-50 MW. A pilot plant at Heber, California is 10 MW size. Dynamics - daily, seasonal, annual Geothermal electric plants are generally used for base (continuous) loads. page 43 GENERATOR COOLING TOWER tL MAKE UP ee FLASH VESSEL DIRECT CONTACT BRINE CONDENSER REINJECTIO PUMP CIRCULATING WATER PUMP BLOWDOWN PUMP CONDENSATE PUMP TO REINJECTION WELLS FROM . PRODUCTION were GEOTHERMAL POWER PRODUCTION BY THE FLASHED STEAM PROCESS FIGURE E1.3-! page 44 Reliability Need for back-up No back-up required for a proven resource, although standby wells are common. Unit back-up required in the event of outage. Availability factor 70 percent availability factor on equipment expected. Storage requirements No special storage required; reservoir provides essentially unlimited storage. Thermodynamic efficiency Up to 12 percent (10-12 percent typical) overall plant efficiency; turbine efficiency alone is around 22 percent. Net energy 27,000 - 34,000 Btu/kWh E.1.3.3 - Costs Capital $1,500/kW installed (California 50 MWe) Assembly and installation N/A Operation N/A Maintenance and replacement N/A ‘Economies of scale Economies of scale are generally advantageous over about 30 MWe and are increasingly disadvantageous below that size. E.1.3.4 - Special Requirements and Impacts Siting - directional aspect, land, height page 45 Typically, 3-5 acres of land with geothermal resource are needed for each MWe; 90 percent of this area is open space between wells and plant facilities. Resource needs Renewab le Assuming geothermal is considered a renewable source, the fluid would have typical characteristics of 340°F @ 115 psia. Non-renewab le N/A Construction and operating employment by skill Highly skilled construction and operating personnel are required. Environmental residuals Air: Hydrogen sulfide gas (H2S) has been a problem at California plants. Cooling water quantities: a function of quality of geothermal water used Health or safety aspects Noise pollution can be a problem, with levels greater than 100 dB for well venting and related activities. Other considerations include disposal of spent fluids, HaS ("rotten egg" smell), and possible surface subsidence. £.1.3.5 - Summary and Critical Discussion Cost per million Btu or KWh 9.84¢/kWh has been reported as levelized busbar cost from a 50 MW California plant. Alaskan costs will be highly site dependent. Resources, requirements, environmental residuals per million Btu or kWh Solid wastes are a function of geothermal fluid composition and can be zero. page 46 Environmental residuals for the Geysers (California dry steam) geothermal electric production are: - Water Bicarbonate: 0.06 pounds/million Btu NOx: 0.02 pounds/million Btu SOx: 0.02 pounds /million Btu Solids: 0.13 pounds/million Btu Organics: 0.03 pounds/million Btu - Air COa: 6.66 pounds/million Btu Ammonia: 0.11 pounds/milion Btu Methane: 0.42 pounds/million Btu HaS: 0.41 pounds/million Btu Critical discussion of the technology, its reliability and its availability oO Geothermal designs are nearly always site specific - technology is not necessarily transferrable. Requires a proven resource. Organic ranking cycle generation is appropriate for low to moderate temperature geothermal resource use. Flashed steam depends upon locating a high temperature wet or dry steam resource. Economy of small-scale flashed steam geothermal conversion is expected to make flashed steam conversion too costly for most village applications. Lower temperature spent fluids may be used for direct heat applications and are expected to favorably affect economics. page 47 E.2 - HYDROCARBON BASED - ELECTRIC TECHNOLOGIES E.2.1 - Diesel E.2.1.1 - General Description Thermodynamic and engineering processes involved: In the diesel engine, air is compressed in a cylinder to a high pressure. Fuel oil is injected into the compressed air, which is at a temperature above the fuel ignition point, and the fuel burns, converting thermal energy to mechanical energy by driving a piston. Pistons drive a shaft which in turn drives the generator. Current and future availability Diesel engines driving electrical generators are one of the most efficient simple cycle converters of chemical energy (fuel) to electrical energy. Although the diesel cycle in theory will burn any combustible matter, operating life considerations require that these engines burn only high grade liquid petroleum or gas, except for multi-thousand horsepower engines which can burn heated residual oi]. Diesel generating units are usually built as an integral whole and mounted on skids for installation at their place of use. £.2.1.2 - Performance Characteristics Energy output Quality - temperature, form In addition to electricity, diesel generators produce two sources of capturable waste heat: from the cooling water and from the exhaust. The cooling water normally is in the 160-200°F range, but it can be 250°F or higher with slight engine modification. Quantity Typically 30 percent of the fuel energy supplied to a diesel-electric set operating at rated conditions is converted to electricity. Typical Alaskan diesel installations range from about 50 to 600 kW, and operate at much lower average efficiency. page 48 Dynamics - daily, seasonal, annual Diesel units are preferably base loaded (not subject to dynamic variations), but in most villages the units are required to follow changing load conditions. Reliability Need for back-up Typically high reliability of low speed diesels appears advantageous for rural Alaskan areas. Although most Alaskan installations are of higher speed ranges (1,800 rpm or greater), proper installation and maintenance allow continuous loading. Unit outages are accommodated through multi-unit installations. Storage requirements Fuel tanks located near the power plant may contain up to 24 months supply. Thermodynamic efficiency Typically 17-31 percent overall plant efficiency Net Energy 11,000 - 20,000 Btu/kWh E.2.1.3 - Costs Capital $350/kW delivered Assembly and installation $650/kW Operation 6 percent of investment per year Maintenance and replacement 2 percent of investment per year for maintenance 8.7 percent of investment for replacement (sinking fund at 3 percent for 10 years) page 49 Economies of scale Diesel electric unit capacities range from approximately 1 kW to 5 MW; initial cost increases significantly per kilowatt for units over 1 MW. E.2.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height A 100 kW unit is typically skid-mounted, weighs about 2 tons, is about 5 feet high, 3-1/2 feet wide, and 9 feet long. The unit requires a foundation, enclosure, and provision for cooling and combustion air. Resource needs Renewab le N/A Non-renewab le No. 2 diesel fuel is typically used. Construction and operating employment by skill Construction can be done with supervised typical local labor and equipment. Operation requires an operator/mechanic. Environmental residuals The composition of the exhaust is a function of the air-fuel ratio and the hydrogen-carbon ratio of the fuel. Residuals include: carbon dioxide, carbon monoxide, hydrogen, and traces of nitrogen oxides and unburned hydrocarbons. Health or safety aspects Fuel-tanks require spill protection, often difficult in remote installations. Potential impacts from such spills include damage to soil, runoff to water courses, fire hazard. E.2.1.5 - Summary and Critical Discussion Cost per kWh is highly site specific with high average load on a large unit for Alaskan village applications (i.e., 300 kW), generating cost may be as low as 12¢/kWh. E.2.2 page 50 Resources, requirements, environmental residuals per million Btu or kWh, From 0.07 to 0.17 gallons of fuel per kWh. Environmental residuals per million Btu: N/A. Critical discussion of the technology, its reliability and its availability. Diesel units are typically stocked by several manufacturers and, as such, have relatively short lead times for use. While this technology is a widely used bush application, lack of qualified operators and availability of spare parts have posed problems in Alaska. - Gas Turbine E.2.2.1 - General Description Thermodynamic and engineering processes involved. In simple cycle gas turbine plants (see Figure E2.2-1), incoming air is compressed and heated through combustion with gas or vaporized liquid fuel injected in a combution chamber. The heated gas expands through and drives turbines which drive the electric generator and the inlet air compressor. Fuel is typically natural gas or very high grade distillate oil. Current and future availability. Gas turbine power plants are a proven, established technology, chiefly used in peaking applications. Base load or cycling applications generally involve waste heat recovery boilers to form a combined cycle plant and require availability of low cost fuel. E.2.2.2 - Performance Characteristics Energy output Quality - temperature, form Electricity and waste heat at typical temperature of 800°F. Quantity Waste (exhaust) heat amounts to 70 to 85 percent of the Btu value of fuel input. ADD FUEL IN HIGH ~~ PRESSURE COMBUSTION CHAMBER “ HOT EXHAUST AT LOW PRESSURE FIGURE E2.2- Ig obec page 52 Dynamics - daily, seasonal, annual Typically used for (daily) peaking loads because operating costs are high relative to fixed costs. Reliability Need for back-up Reliability of petroleum based fuel supply is an issue. Back-up for peaking applications typically approached using multiple units, as peaking units often exhibit high unavailability. Installation lead time is generally short. Storage requirements Natural gas is typically provided by pipeline. Distillate oi] fuels require tank storage. Thermodynamic efficiency Simple cycle turbines have typical thermal efficiencies at rate load of about 28 percent at sea level and 70°F. Efficiency varies significantly with temperature, elevation, model, and load. Net energy 10 ,500-22 ,000 Btu/kWh E.2.2+3 i= Costs Capital $550/kW engine-generator , (800 KW) Assembly and installation $1 ,100/kW Operation Large utility units often start, run and stop by remote control. Alaskan city applications would generally have a part-time operator; estimate $55,000/yr. Maintenance and replacement 2 percent of initial investment per year for maintenance page 53 3.7 percent of initial investment per year replacement (sinking fund at 3 percent for 20 years) Economies of scale Units range in size from 30 kW to over 100 MW. Cost per kilowatt decreases noticeably up to unit size range of 20 MW. E.2.2.4 - Special Requirements and Impacts Siting - directional aspect, land, height A typical 800 kW gas turbine weighs around 17,000 pounds, is 18 feet long by 6 feet wide, and about 6 feet high. The unit comes with its indoor enclosure, and requires fuel and air supplies an exhaust connection, and a weather enclosure. Resource needs Renewab le N/A Non-renewab le Natural gas is a near ideal fuel. Light distillate oils are also satisfactory. Blade path corrosion is caused by sulfur, vanadium, or other metals, and impurities must be considered when selecting fuels. Construction and operating employment by skill. Construction can be performed with supervised local labor and equipment. An operator/mechanic is required. Environmental residuals Oil fired turbines: NOx, SOx, particulates Gas fired turbines: NOx Since gas turbines require clean burning fuels, most stack gas emissions are negligible except for NOy. Health or safety aspects Integration of gas turbine generating units in a community rarely causes any significant negative health or safety impacts. Most noticeable impact is engine noise, which can generally be controlled to unobjectionable levels. page 54 E.2.2.5 - Summary and Critical Discussion Cost per million Btu or kWh A highly loaded 800 kW machine can be expected to generate power for 19¢/kWh on oi] fuel costing $1.20/gallon. Resources , requirements, environmental residuals per million Btu or kWh. Need .08 to .17 gallons of turbine fuel per kWh Environmental residuals per million Btu: N/A Critical discussion of the technology, its reliability and its avai lability. Gas turbines are a well established technology in the U.S. generating mix. This generation plant type accounts for about 10 percent of U.S. installed capacity and is used primarily to provide peaking power and reserve generating capacity. Operation has been proven in much of Alaska, although time required for maintenance and parts acquisition tend to take longer than in the lower 48. In its simplest form, the gas turbine is compact and relatively light, does not require cooling water, runs unattended, and can be remotely controlled. In order to be most efficient, however, gas turbines should be run at or near full load. page 55 E.3 RENEWABLE RESOURCE BASED ELECTRIC SYSTEMS E.3.1 - Hydroelectric Generation £.3.1.1 - General Description Thermodynamic and engineering processes involved: In a hydroelectric power development, flowing water is directed into a hydraulic turbine where the energy in the water is used to turn a shaft, which in turn drives a generator. Turbines involve a continuous transformation of the potential and kinetic energy of the water into usable mechanical energy at the shaft. Water stored at rest at an elevation above the level of the turbine possesses potential energy (head); when flowing, the water possesses kinetic energy as a function of its velocity. The return of the used water to the initial source is performed through the hydrologic cycle of solar evaporation, rain and runoff to a body of water for re-evaporation - a direct natural process using solar energy (Figure £3.1-1). The ability to store water at a useful elevation makes this energy supply predictable and dependable. Current and future availability. Hydropower presently provides about 10 percent of Alaska's electric energy needs. Worldwide developments range in size from over a million kilowatts down to just a few kilowatts of installed capacity. Hydropower is a time proven method of generation that offers unique advantages. Fuel cost, a major contributor to thermal plant operating costs, is eliminated. A major advantage of hydropower developments is that they last much longer than do other plant types. Hydropower developments are, however, initially costly. Lead time can be as much as 20 years for very large projects, from initial reconnaissance to commissioning. Licensing procedures for smaller projects, are being streamlined. Streamlining licensing procedures can significantly reduce the amount of lead time needed to bring a project on-line. £.3.1.2 - Performance Characteristics Energy output Quality - temperature, form Me za ~~ ~p- AYE ENERGY HYDROELECTRIC = = . PLANT EVAPORATION | ! FIGURE €E3 -l page 57 Hydropower provides readily regulated electricity. Water quality is not affected. A slight temperature differential may exist between discharge water and the receiving waters. Quantity Typical installed capacities in Alaskan power plants range from 1-20 MW, although larger projects are being examined. Dynamics - daily, seasonal, annual Hydropower plants can be base loaded and/or peak loaded depending upon site characteristics. In smaller install- ations, the operating mode may be adjusted seasonally, depending on the availability of water and the demand for electricity. Reliability Need for back-up The reliability of the hydroplant itself is very high. The transmission lines are often routed through very rugged terrain and are consequently subject to a variety of natural hazards. Repairs to damaged lines can usually be accomplished relatively quickly. In Alaskan applications, typical approach is to provide sufficient installed diesel generation capacity to provide emer- gency electricity to the utility's customers in the event that the transmission line or the power plant should go down. The amount of backup required can be reduced by building an alternative transmission line. Storage requirements Some sites will permit behind the dam storage, allowing use of the plant to meet variable demand. Reservoirs can range in size from a few thousand square feet to thousands of acres for major projects. Thermodynamic efficiency Net For small plants, approximately 80 percent of the energy stored in the water will result in saleable electricity. The remaining 20 percent will be lost in the water conduit, turbine, generator, station service loads, transformers, and the transmission line. energy N/A page 58 E.3.1.3 - Costs Capital Capital cost is highly site specific. For plants below 1 MW in capacity, cost of installation can easily exceed $20,000 per kW. Installation - cost, therefore, depends on both site conditions and cost of alternative generating methods. (The plant will not be built if other methods are available at lower life cycle cost.) Assembly and installation (included above) Operation and maintenance Operation and maintenance costs for a hydroelectric development normally depend on the size of the installation and the method of operation. Most large installations will be attended full-time while many of the smaller installations are operated remotely and visited only occasionally for maintenance. Typical annual operation and maintenance cost for large installations is $.001/kWh produced plus $5/kW of installed capacity. For small plants, costs may increase to as high as $.10/kWh and $10/kW. Economies of scale See above. E.3.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height A suitable site for any hydropower development must, of course, be found. Requirements include an adequate water supply and a reasonable proximity to the load center (consumers). Site preparation for a hydropower development may involve modification of the existing terrain with resulting changes in both the topography and in the natural or existing drainage. pattern. Small run-of-the-river installations may require minimal dam construction or disturbance of the area. The project boundary (the outer limits of the land directly affected by the project) May encompass several hundred acres. The impacts of a hydropower development primarily fall within the areas of land use and stream ecology, with severity depending on the site. A special advantage of a hydropower development is that it is effectively non-polluting. page 59 Resource needs Renewab le Rainfall and catchment Non-renewab le N/A Construction and operating employment by skill Construction of a hydropower development requires the employment of highly skilled individuals experienced with equipment installation and startup, typical construction trades and laborers who usally come from the local workforce. Operators of hydroplants are often drawn from the local population and given training to qualify them for the position. Environmental residuals None Health of safety aspects Public safety, legal liabilities, insurance, and land use issues must be addressed prior to construction of a hydropower development. E.3.1.5 - Summary and Critical Discussion Cost per million Btu or kWh Site specific Resources , requirements, environmental residuals per million Btu or kWh. Site specific Critical discussion of the technology, its reliability and its avai lability. Hydroelectric power generation is a well established technology. Although each project, and many of its components, are generally "custom" design jobs (particularly with large projects), significant progress has been made towards producing standardized components for small scale plants. With recent simplifications page 60 of the licensing procedures, small plants (i.e., 500 kW) can now be designed and operating within a few years. Hydroplants can be remotely operated from a central station. At large scale plants, an operator is usually stationed at the plant to take care of routine maintenance. Small scale plants suitable for supplying power to a village would normally run unattended. Safety of large hydropower developments has long been a concern of the Federal and State governments. Criteria for safe design and operation of hydropower developments are well etablished and major failures are very rare. The hydraulic turbine, and its component parts, are designed and are built to exacting specifications and is extremely reliable; the turbine often has a useful life of upwards of 50 years. E.3.2 - Wind Energy Conversion Systems E.3.2.1 - General Description Thermodynamic and engineering processes involved The thermodynamic process involved stems from the sun, the primary energy source which produces the wind. Wind energy cannot be stored, is intermittent, generally unpredictable and thereby undependable as a source of firm energy. Most wind generators rely on wind flow over an air foil assembly to create differential pressures along the air foil. This differential pressure results in rotation of the assembly around a fixed axis (drive shaft) to which it is attached. Power from the wind is transmitted through the drive shaft and accompanying gear box to an electric generator. (See Figure £3.2-1). Three types of generators are presently in use with wind energy systems. These are the DC generator, the AC induction generator and the AC synchronous generator. Of the three types the AC induction generator is the most widely used: an induction generator is not a stand-alone generator and must be connected to an external power system of relatively constant frequency and voltage to operate properly. Current and future availability Estimation of availability of wind at useful velocities require long-term records to estimate the potential energy. Lesser records provide less credible estimates. Availability of small size units in the 1.5 kW to 20 kW range is good. Large units (100 kW and above) are currently being demonstrated in both the government and private sectors and are v HORIZONTAL AXIS_ WIND TURBINE GENERATOR GEARTRAIN AND GENERATOR HOUSING WIND (Any Direction) VERTICAL AXIS WIND TURBINE GENERATOR WIND TURBINE GENERATORS FIGURE 19 abed page 62 commercially available in sizes of 200 MW scale. Demonstrations of multi-megawatt sizes are in process. E.3.2.2 - Performance Characteristics Energy output Quality - temperature, form Electricity Quantity Wind generator output generally ae as a function of the wind velocity to the third power (v3 ), beginning at a cut-in wind velocity (normally about 8 mph) up to a cutoff wind velocity, i.e., a machine rated at 200 kW in a 27 mph wind can be expected to produce the following in lighter winds: 7 mph: machine will not operate 12 mph: 17 kW 18 mph: 59 kW 24 mph: 140 kW 30-36 mph: typical cut out speed Actual performance will vary from one design to the next. Reliability Need for back-up In general, except for the small single dwelling wind/battery systems, wind power generation is not a stand alone system. Diesel or another form of back-up generation must be provided for days that the wind does not blow with sufficient velocity to produce adequate energy from the WECS. Additionally, normal operating mode would be in parallel with an on line diesel. The diesel would generate the bulk of demanded power output and adjust its load according to the instantaneous output of the wind generator. Storage requirements Batteries can be used for storage, at considerable expense. The most cost effective way to use wind power on a utility grid appears to be through direct displacement of fuel otherwise required for diesel generation without attempting to store the wind energy (as described above). page 63 Thermodynamic efficiency Actual conversion efficiency of wind turbine is generally on the order of 40 percent of available wind energy. Net energy N/A E<332.3 = Costs Capital Machine size Type Cost $/kW 200 kW horiz axis $550,000 (FOB) $2,800 50 kW vertical axis $150,000 (FOB) $3 ,000 10 kW horiz axis $ 18,000 $1,800 Assembly and installation One example of a 200 kW horizontal axis mchine has been constructed in a remote area without use of a crane. The machine was constructed (using a gin pole and electric hoist) piece by piece from the ground up. This is considerably more expensive than a crane (when available), but will probably be required for most Alaskan villages. Installation costs in rural Alaskan villages are estimated to be roughly $2,800/kW for all classes of machine sizes. This may vary somewhat in those villages where there exist conditions which significantly expedite or complicate installation work. Delivered and erected cost is estimated to be roughly double the cost of the basic equipment. Operation and Maintenance Barring major equipment failures, annual operating costs for horizontal axis machines in the 200 kW class are expected to be limited to occasional adjustment and inspection, with periodic preventive maintenance. page 64 Estimated Operation & Unit Size Maintenance Replacement Total/Yr. 200 kW (hor) $8,000 Est $16,000 $24,000 Economies of scale Economies of scale generally favor installation of large centralized wind generators over the small individually owned wind generators. This is less the function of wind turbine cost than of system opera- ting limitations and their effect on total system cost. Unit sizes are, of course, restricted by village power requirements. Because of electrical system stability limitations, the total installed WECS instantaneous output should not exceed 25 percent of the total system load. Siting - directional aspect, land, height Siting requires the selection of a location with average annual wind speeds approaching or exceeding 10 mph. Height of the mounting tower will vary depending on location and machine size and type. A 200 kW horizontal axis unit can be expected to be 150 feet high from blade tip to ground, with a 90 foot tower. Resource needs Renewab le Average annual wind speed in excess of 10 mph (typical). Although some machines may operate in lighter winds, output will be minimal. Non-renewab le N/A Construction and operating employment by skill Certain aspects of construction (i.e., foundation, tower installation) could be performed by unskilled labor under close supervision. An operator would not be required for horizontal axis turbine, as these are operated unattended. Vertical axis designs (Darrieus) require a start-up system and, therefore, a part-time operator. Environmental residuals Aside from visual impact, little environmental impact is E353 page 65 anticipated when operating only a few machines within a small geographic area. Electromagnetic communications interference and very low frequency sound generation have been problems with recent units. Health or safety aspects Public safety, legal liabilities, insurance and land use issues must be addressed prior to installation of a utility owned or operated WECS. Primary concerns are blade failure and tower or foundation failure in high winds. E.3.2.5 - Summary and Critical Discussion Cost per million Btu or kWh Site specific Resources, requirements, environmental residuals per million Btu or kWh N/A Critical discussion of the technology, its reliability and its avai lability. Wind power suffers from one obvious disadvantage; the intermittent and fluctuating nature of wind. A small utility must install sufficient primary generation at additional costs to Meet demands on those days when the wind does not blow with sufficient velocity to produce a significant output from the WECS. Besides the fickleness of local wind conditions, technical, environmental, and social problems must be addressed. Technical and social barriers that must be dealt with include power system stability; voltage transients, harmonics; fault-interruption capability; effects on communications and TV transmissions, public safety; legal liabilities and insurance, and land use issues. - Photovoltaic Cells E.3.3.1 - General Description Solar cells are electric energy generators that consume no fuel, make no noise, pose no health or environmental hazards and produce no waste products. These cells convert light directly into electricity page 66 via light sensitive semiconductors. Since no moving parts, no high pressures and no high temperatures (excluded focused collector designs) are involved, this would be an ideal way of generating electricity. E.3.3.2 - Performance Characteristics Efficiency of conversion to electricity is about 12 percent. E.3.3.3 - Costs Today, solar-cell power is too expensive to compete with fossil-fuel power for all but the smallest applications in unattended service where cost of power is of little concern. The single crystal silicon solar cell has a laboratory or rated efficiency of about 12 percent and costs $10.00 per peak watt or $10,000 per peak kilowatt. In-field panel efficiency is generally lower than rated efficiency for cell arrays, due to cell and panel mismatches, elevated operating temperature and wiring and conversion losses. These cells must ‘be mounted in a cell array panel, with a support and aiming structure. In addition to the cell array, storage equipment (batteries) and inverters will be required if a “stand alone system" is desired to supply the equipment and devices presently in use with electric energy. Energy storage helps satisfy demand during periods of little or no sunshine, as well a supplying peak power. Presently available storage devices are lead-acid batteries, which are expensive. The life of a lead-acid battery is limited to a few years with daily cycling, even with a charge controller. Costs for a complete stand alone system rated at a peak output of 5kW, based upon appropriate storage for a lower 48 state application were estimated by a major manufacturer as $20 per peak watt, or $100,000. The application of such a system at an Alaskan site was seen as likely to require a significant increase in battery capacity as latitude approached the Arctic circle and increasingly limited usefulness in winter regardless of battery capacity. Cost breakdown provided for the lower 48 system is as follows (on an approximate basis): Cell arrays $10/watt Array support, structure, controls $ 3/watt Batteries $ 5/watt Inverter $ 2/watt $20/watt page 67 Breakthroughs in cell cost are anticipated, but will likely be offset for stand-alone residental Alaskan applications by battery requirements. Thus the manufacturer saw little potential for the Alaskan market. E.3.3.4 - Summary and Critical Discussions The costs of both photovoltaic cells and low-maintenance storage mediums must be reduced before they can economically compete with conventional generation of electric energy. At $20 per peak watt, annual replacement allowance with a 20-year life is $6,700 for a5 kW system using the 3 percent cost of money rate assumption. This is equivalent to 76.4 cents per kilowatt hour if the system were to produce an average of 1 kWh for every hour of the year. Any repair or cleaning costs are additional. A backup generating system or extensive battery storage will be required for extended periods of darkness and/or cold weather, adding to initial cost beyond the $20 per peak watt figure. Batteries will also need replacement every five to ten years if properly maintained. page 68 £.4 HEATING TECHNOLOGIES £.4.1 - Diesel Waste Heat Recovery E.4.1.1 - General Description Thermodynamic and engineering processes involved The present use of fossil fuels (coal, gas, oil) to produce more useful forms of energy (heat, electricity, motive power) is less than 100 percent efficient. For example, if a machine burns a certain quantity of fossil fuel and produces useful output (shaft horsepower, electrical energy, steam, hot water or air for space heating) equivalent to 30 percent of the fuel burned, the energy represented by the remaining 70 percent of the fuel will appear as unused or "waste" heat. Such heat most often appears as hot exhaust gas, tepid to warm water (65°F-180°F), hot air from cooling radiators, or direct radiation from the furnace, steam power plant, diesel engine, etc. Diesel waste heat can be recovered from engine cooling water and exhaust (as shown in Figure E4.1.1), or either source separately. The waste heat is typically transferred to a water-glycol circulating system in Alaskan applications. The heated circulating fluid can be used for space, water, or process heating. Current and future availability Recovery of diesel waste heat in Alaska is growing as a result of sharp increases in diesel fuel costs. Recovery of jacket water heat only is most common in Alaska and is shown in Figure £4.1.2. Diesel waste heat availability is directly related to the location and operating cycles of the engine installation. E.4.1.2 - Performance Characteristics Energy output Quality - temperature, form Cooling water is typically 160-200°F. Exhaust heat varies with engine speed and load and ranges from about 300-600°F. page 69 TO REMOTE FROM REMOTE HEAT LOOP HEAT LOOP EXHAUST GAS (i EXPANSION TANK EXCHANGE: = c. ie cA H CHECK VALVE (‘S} VALVE DOAP—-OPwD D-> Loy MOTOR | ee ee BOOSTER THERMOSTATIC PUMP CONTACTOR =orn | ENGINE THERMOSTAT JACKET WATER & EXHAUST WASTE HEAT RECOVERY SYSTEM FIGURE E4.1-1 page 70 SPACE HEAT THERMOSTATIC VALVE THERMOSTATIC ee ENGINE THERMOSTATIC SWITCH JACKET WATER WASTE HEAT RECOVERY SYSTEM FIGURE E4.1-2 page 71 Quantity Diesel engines generally convert about 30 percent of the fuel input to shaft power which can be converted to electricity, 30 percent as cooling water heat, 30 percent as exhaust heat, and 10 percent as radiation loss. All of the cooling water heat, about half of the exhaust heat, and all of the radiation can be usefully captured if space heat needs are in economic proximity. AVERAGE ANNUAL HEAT LOAD FOR VARIOUS COMMUNITIES Average Average Annual Degree Temperature Heat Load Location _Days_ (°F) (Btu x 105) Anchorage 10,814 35.24 147.9 Barrow 20 ,174 9.73 256.4 Bethel 13,196 28.85 175.0 Cordova 9,764 38.25 135.1 Fairbanks 14,279 25.88 187.7 Juneau 9,075 40.14 127.0 King Salmon 11,343 33.92 153.5 Kotzebue 16,105 20.88 209.0 Nome 14,171 26.18 186.4 1 Based on a "standard" 10,000 ft3 building, 35' X 35' X 8'. Walls of 2" X 4" construction on 16" centers, with R-11 insulation, U factor .07. Roof and floors 2" X 8" or 2" X 12" on 16" centers, unheated attic, 6 inches of insulation, U factor .07. Two 24" X 40" windows, 1 1/2 air changes per hour. page 72 Table £4.1.1 indicates the annual recoverable waste heat for various diesel unit sizes and generating efficiencies (i.e., kWh/gal and heat rates in Btu/kWh) and assumes that one-third of the fuel heat is recoverable. TABLE E.4.1.1 WASTE HEAT AVAILABILITY2/ 106 Btu/year Available at Indicated Generating Efficiency 12 kWh/gal 10 kWh/gal 8 kWh/gal kW kWh/year (11,500 Btu/kWh) (13,800 Btu/kWh) (17,250 Btu/kWh) 50 175,200 671.6 805.9 1,007.4 75 262,800 1,007.4 1,208.9 1,511.1 100 350,400 1,343.2 1,611.8 2,014.8 200 700,800 2,686.4 3,223.6 4,029.6 1/ Assumes 138,000 Btu/gal fuel, 0.40 load factor. Dynamics - daily seasonal, annual Waste heat is available whenever the electrical generation source it is dependent upon is in operation. Reliability Need for back-up Heat recovery systems require a back-up heat source in case of system shutown. This is typically provided by boilers and heaters that existed prior to installation of the recovery system and were consequently idled by it. Storage requirements Waste heat is generally utilized as it is recovered; storage of heat is atypical. Thermodynamic efficiency Net N/A . energy N/A page 73 E£.4.1.3 - Costs Capital Waste heat utilization is not free, even though there may not actually be a direct charge for the heat. The equipment for utilizing this heat requires a sizeable capital investment and is feasible only when the cost for associated equipment is less than the cost of the fuel saved. The cost of heat exhangers, waste heat boilers and associated equipment depends on the generator installed at the location. These costs can be determined by contacting the generator's manufacturer and obtaining the price of the specific models of waste heat recovery equipment specifically designed for that generator. Using some typical prices as a guideline, we can estimate that the component price for a heat recovery silencer will range from $4,900 for a 55 kW engine-generator set to $21,000 for an 850 kW engine-generator. These units would allow capture of waste heat equivalent to approximately one-sixth of the fuel supplied to the engine-generator. To these prices must be added the cost of installation and auxiliary equipment with a potentially major investment required in distribution systems. A heat exchanger for the jacket water system will range from perhaps $1,200 for a 55 kW engine-generator set to perhaps $5,100 for the 950 kW engine-generator set. These theoretically can capture waste heat equivalent to approximately one-third the fuel supplied to the engine-generator. Overall cost is site specific: a complete system recently installed in Angoon to provide heat to 4 buildings from 3 diesel generators cost $190,000 installed (1981). Operation N/A Maintenance and replacement 2 percent of capital investment per year for maintenance 3.7 percent of investment per year for replacement (sinking fund using 3 percent for 20 years) page 74 Economies of scale Small systems may be as beneficial economically as very large systems because required equipment is less sophisticated and consequently less costly. Cost of redundant system is typically lower (per unit recovered) in smaller systems, also. E.4.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height Should be immediately adjacent to diesel engine (or other heat source). Resource needs Renewab le N/A Non-renewab le Waste heat recovery uses an otherwise lost resource Construction and operating employment by skill Jacket water heat recovery systems can be installed and operated by local personnel qualified for similar work with diesel generators. Environmental residuals Environmental residuals are only those associated with the means of electical generation employed, the reduction of waste heat release is a net benefit. Health or safety aspects “ No negative health or safety aspects except those previously associated with the heat source. £.4.1.5 - Summary and Critical Discussion Cost per million Btu or kWh~ Site specific page 75 Resources, requirements, environmental residuals per million Btu or kWh. These items are a function of the heat source. Critical discussion of the technology, its reliability and its availability. Waste heat capture, while not a fuel for generation, can provide savings in overall fuel use. Engine cooling water can be used in two ways: 1) the hot coolant from the engine or industrial process can be piped directly to radiators in the space to be heated, or to other processes which can use the heat; or 2) the hot coolant can, via heat exhanger, heat a medium, probably water, which will be used for space heating or other processes. Most engine manufacturers advise against the first approach. A leaking radiator can destroy the engine, whereas in the second system the engine will be less affected. Engine water must be soft and free of impurities that could reduce the heat transfer in the engine. This can be controlled in a small system using the same water over and over, but is much more difficult in a system where engine water is circulated through the heating system. The second approach involves lower effectiveness of heat recovery, but is the most common method employed when utilizing the waste heat from the engine cooling water. The critical point of any effort to evaluate waste heat recovery is that point at which the equivalent annual cost of recovering heat will be less than the cost of generating heat by other means. Low grade waste heat cannot be transported very far for its actual resale value. E.4.2 - Electric Heating £.4.2.1 - General Description Thermodynamic and engineering processes involved Electricity is passed through resistance wiring thereby generating heat. The heat is transferred to air or water. Current and future availability Electric heat is clean, noiseless, easily controllable and relatively efficient. Electric heat is a recognized means of heating buildings where heat losses are held to a low level and the cost of electricity is not prohibitive. page 76 £.4.2.2 - Performance Characteristics Energy output Quality - temperature, form Heat or hot water for space heating applications Quantity 3,412 Btu out per kWh in. Dynamics - daily, seasonal, annual Available whenever there is electricty. Reliability Need for back-up Typically, none with a highly reliable electric supply system. Storage requirements None Thermodynamic efficiency So far as the conversion of electric energy into heat is concerned, all types of electric resistance heaters are equally efficient. They all produce 3,412 Btu per kilowatt-hour of electrical energy used. From a thermodynamic efficiency standpoint, electric heaters are 100 percent efficient at the place of use. E.4.2.3 - Costs Capital Approximately $2,100 for a central home system (installed). Operation A function of the cost of electricity Maintenance and replacement Virtually maintenance free; replacement life estimated to be 20 years. page 77 Economies of scale Not appropriate. E.4.2.4 - Special Requirements and Impacts Siting - directional aspect, land, height In typical residential installations, a metal casing, in the same configuration as conventional baseboard along walls, contains one or more heating elements placed horizontally. The vertical dimension is usually less than 9 inches, and projection from wall surface is less than 3.5 inches. Units are available from 1 to 12 feet long with ratings from 100 to 400 watts per foot of length and are designed to be fitted together to make up any desired continuous length or rating. Resource needs Renewab le N/A Non-renewab le Electricity Construction and operating employment by skill Simple to install and effectively automatic Environmental residuals None Health or safety aspects None with proper installation. £.4.2.5 - Summary and Critical Discussion Cost per million Btu or kWh Cost is a function of the cost of electricity The most economical electric heating systems from an operating standpoint are of a decentralized type, with a thermostat provided on each unit or for each room. This permits each room E.4.3 page 78 to compensate for heat contributed by sources auxiliary such as sunshine, lighting, and appliances. This arrangement also gives a better diversity of the power demand due to noncoincidence of electric load from all units of an installation. Manual switches are often provided to permit cutting off heat or reducing temperature in rooms when not in use. Resources, requirements, environmental residuals per million Btu or kWh, A function of the resource used to generate electricity. See appropriate Appendix C profiles. Critical discussion of the technology, its reliability and its avai lability. In summary, a simple list of some of the benefits and advantages of electric heat includes the following: Dependable No fuel deliveries No fuel storage problems Clean No venting required No oxygen consumption Individual room-by-room control Quiet Easy to install Space-saving "Flameless" - Passive Solar Heating E.4.3.1 - General Description Passive solar heating makes use of solar energy (sunlight) through energy efficient design (i.e., south facing windows, shutters, added insulation) but without the aid of any mechanical or electrical inputs. Space heating is the most common application of passive solar heating. Because such solar heating is available only when the sun shines, its availability is intermittent (day-night cycles) and variable (winter-summer cloudy-clear). E.4.3.2 - Performance Characteristics The southeast Alaska area is located roughly between 55° and 60° North latitudes. The possible insolations shown on Table £4.3.1 for Juneau and Yakutat are considered to approximate conditions within this area. The annual amount of solar energy available could satisfy page 79 TABLE 4.3.1 SOUTHEAST ALASKA - SOLAR ENERGY AVERAGE SOLAR INSOLATION INSOLATION ON 200 SQ. FT. HEATING ENERGY REQUIREMENTS ON A SOUTH-FACING WALL OF SOUTH-FACING WINDOWS HEATING DEGREE-DAYS OF AN 800 SQ. FT. RESIDENCE (Btu/sq ft + day) (1,000 Btu/sq ft - day) (°F + day @65°F) (1,000 Btu/day) MONTH JUNEAU YAKUTAT JUNEAU YAKUTAT JUNEAU YAKUTAT JUNEAU YAKUTAT JAN 200 279 58 56 1287 1265 21 276 FEB 448 450 9 9 1036 1036 226 226 MAR 668 732 134 146 1026 1076 224 235 APR ™7™ 801 154 160 783 867 171 189 MAY 706 705 141 141 564 673 123 147 JUN 691 669 18 1x 354 459 77 100 JUL 655 628 131 126 28 360 63 79 AUG 612 594 122 119 332 375 73 82 SEP 553 569 ll 114 474 498 104 109 OCT 408 502 82 100 719 753 157 164 NOV 319 321 64 4 965 984 ail 215 DEC 119 107 24 al 1169 1187 255 259 Note: Data for this table taken fran "Alaska Solar and Weather Information", Western SUN, Portland, OR, 1980 E.4.4 page 80 area. The Bethel and Fairbanks data has been developed with the F-chart computer program and takes climate and typical weather conditions into account. The annual amount of solar energy available can satisfy all heating needs of an average home if enough collecting surface area and adequate storage could be installed. Heat storage or supplement heating by other means would be necessary for about 6 months of the year when the available insolation cannot satisfy the heating needs. If passive solar heating is considered, where the solar energy is sufficient and with energy efficient design (increased insulation, south facing windows with shutters, etc.) it is conceivable that even in the months of November, December and January approximately 10-30 percent of the required heat can be supplied by the sun if 200 square feet of south facing windows can collect energy for an average size (800 sq.ft.) residence found in the Alaskan bush. E.4.3.3 - Costs The integration of passive solar heating into the design and construction of a new residence adds little to the overall structure cost. Typical increases in structure costs range for 0 to 5 percent. In general, it is not economical to extensively remodel existing residences to take advantage of passive solar heating. - Coal Fired Furnace E.4.4.1 - General Description Thermodynamic and engineering processes involved. Coal is manually or automatically fed to a controlled combustion chamber equipped with heat exchange surfaces and an exchange fluid circulating system. Designs are available for either forced hot air or hydronic (hot water) systems. Current and future availability Units are commercially available. E.4.4.2 - Performance Characteristics Energy output Quality, temperature, form Heat page 81 Quantity Unit sized range upwards from approximately 100,000 Btu/hr for “high technology" units; combination wood/coal stoves are also available. Dynamics N/A Reliability Need for backup A portable oi] heater might be kept as a standby Storage Requirements Adequate coal in storage for full heating season (including reserve) in moisture protected bin. Thermodynamic efficiency 50 to 70 percent for "high technology" units; 30 to 70 percent for stoves. Net Energy N/A E.4.4.3 - Costs Capital Investment can range up to $32,000 per million Btu/hr for fully automated home sized hot air system. Commercial building sized systems approach $43,000 per million Btu/hr. Installation Transport and installation expected to equal equipment cost. Operation; maintenance and replacement Depends upon -system and coal used. Maintenance not expected to exceed $500 per year of use. Replacement sinking fund payment per year (at 3 percent for 20 years) is 3.7 percent of initial installed cost. E.4.5 page 82 Economy of Scale N/A E.4.4.4 - Special Requirements and Impacts Siting - directional aspect, land, height Building heating system must be compatible; building layout must accommodate size of unit and access requirements to coal bin location. Ash disposal area required. Resource needs Renewab le N/A Non-renewab le Coal must be available in adequate quantities Construction and Operating Employment by skill Factory representative might provide direction to local labor for the more elaborate designs. Environmental Residuals Solids: stack particulate, ash for diposal Health or Safety aspects Normal care required around heated surfaces. - Wood Fired Furnace E.4.5.1 - General Description Thermodynamic and engineerng processes involved Wood is manually fed to a combustion chamber designed for radiant/convective heating, radiant forced convective heating or hydronic heating. Current and future availability Commercially available and widely in use. page 83 £.4.5.2 - Performance Characteristics Energy Output Quality, temperature, form Heat Quantity Usable stove outputs range from 10,000 Btu/hr and up. Dynamics Depend upon operator Reliability Need for backup Generally reliable with reasonable attentiveness to fire and stack cleaning. Portable oi] heats might be kept as standby. Subject to wood availability. Storage Requirements Wood storage requirements are site specific Thermodynamic Efficiency Perhaps 20 percent for some homemade designs up to nearly 80 percent for some airtight designs. Net Energy N/A E.4.4.5 - Costs Capital Minimal for homemade stoves, can approach $21,000/million Btu/hr for some airtight designs on market. Installation From negligible to equal to equipment cost page 84 Operation, Maintenance and Replacement Widely variable maintenance needs with operating practices, unit design and wood used; replacement sinking fund payments (at 3 percent for 15 years) are 5.4 percent of initial cost per year. Economy of Scale N/A E£.4.4.6 - Special Requirements and Impacts Siting - directional aspect, land, height Building design must accommodate stove type selected. Resource needs Renewab le/Non-renewab le Wood requirements will be site specific based upon heating value, desired heat level, stove operating practices. Wood supply may be effectively non-renewable with overcutting of a slowly growing tree stock. Construction and Operating Employment by skill No special skills generally required unless high efficiency masonry designs are to be installed. Environmental Residuals Solids: particulates, ash for disposal Land: tree cutting and transport impacts. Health or Safety Impacts Primary impacts are safety hazards of cutting and splitting wood; normal care around heated surfaces. page 85 E.5 - FUEL CONVERSION TECHNOLOGIES E.5.1 - Coal Gasification E.5.1.1 - General Description Thermodynamic and engineering processes involved Low or medium Btu gas (100-300 Btu/scf) can be manufactured from coal in commercially available equipment. However, the use of this gas for power generation is a very complex process, as depicted in Figure £5.1-1. Current and future avai lability The prospect of coal gasification contributing to Alaska power in the next 10 years is remote for other than demonstration type plants. Existing commercial facilities and development projects are far too large in scale for village applications. E.5.1.2 - Performance Characteristics Energy output Quality - temperature, form Gas of 100-300 Btu/scf Quantity Depends on quantity of feedstock available and desired output. Process equipment is generally custom built. Dynamics - daily seasonal, annual Gasifiers are best operated on a continuous basis. Reliability Need for back-up Fossil power systems displaced by gasification would typically be used for back-up. Storage requirements Like coal-fired steam plants, a 3-month fuel supply is typical. Extreme climates may require up to 9 months worth of coal in storage. Page 86 S )GENERATOR —— — —AIR EXHAUST HS GAS TURBINE DESORBER SATURATOR ABSORBER COOLER eS TAR OIL COAL GASIFIER FEEDWATER CLEAN FUEL GAS FROM COAL FOR POWER GENERATION FIGURE E5.1-1 page 87 Thermodynamic efficiency 65 percent to 85 percent conversion of fuel feedstock to usable energy form. Net energy N/A E.5.1.3 - Costs Capital N/A Assembly and installation N/A Operation N/A Maintenance and replacement N/A Economies of scale "Small" commercial units produce about 2 billion Btu per day. E.5.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height As for coal-steam plants, fuel storage is the major land requirement. Gasification at the mine can cut storage requirements to 30 days. A representative 1,000 kW gasifier is reported to be about 60 feet high and 8-10 feet in diameter. Resource needs Renewab le N/A Non -renewab le Coal of virtually any quality can be utilized. Construction and operating employment by skill Highly skilled construction and operating personnel are required. page 88 Environmental residuals Solids: ash, sulfur Air: SOy and particu lates Health or safety aspects The low Btu gas is highly flammable and generally contains high levels of toxic carbon monoxide. E.5.1.5 - Summary and Critical Discussion Cost per million Btu or kWh Lower 48 costs of a "small" commercial unit is $3.00 per million Btu per a manufacturer's estimate for 5 billion Btu per day. This cost may increase by a factor of 2-3 for Alaska. Resources, requirements, environmental residuals per million Btu or kWh Need 1.2 Btu in fuel (or more) for each Btu of gas generated. Environmental residual figures are based on an ash agglomerating fluidized bed low-Btu gasification process: Sulfur: 2.77 pounds/million Btu NOx: 0.02 pounds/million Btu SOx: 0.04 pounds/million Btu Particulates: 0.14 pounds/million Btu CO; 0.01 pounds /million Btu Solids: 13 pounds/million Btu Critical discussion of the technology, its reliability and its avai lability. While coal could be gasified in a so-called synthetic fuel plant, the state of the art and associated economics make it appear doubtful that a fuel facility would be constructed solely for the purpose of providing fuel for limited electrical generation. Suitable low-Btu gasifiers are air blown units of the fixed bed type operating at atmospheric pressures. These units are "small": daily production is less than 2 billion Btu of hot, raw gas. Low-Btu gas is economically attractive only if produced near its usage - nominally within a half mile. The cost of the gas in the lower 48 is expected to range up to $5.00 per million Btu. Actual cost as a specific location is influenced by the price of coal (about half the production cost), the load factor, the gas cleanup requirements for specific process use, and clean air requirements. page 89 E£.5.2 - Wood Gasification E.5.2.1 - General Description Thermodynamic and engineering processes involved Low Btu gas (100-300 Btu/scf) has been manufactured from wood in equipment under development in Alaska. Gas is produced through partial combustion at high temperature in an oxygen starved atmosphere. Current and future availability The prospect of wood gasification contributing to Alaska power in the next 10 years is remote for other than demonstration type plants. Very few commercial facilities operating in conditions equivalent to village applications are known to exist. E.5.2.2 - Performance Characteristics Energy output Quality - temperature, form Gas of 100-300 Btu/scf Quantity Depends on quantity of feedstock available and desired output. Process equipment is generally custom built. Dynamics - daily, seasonal, annual Gasifiers are best operated on a continuous basis. Reliability Need for back-up Fossil power systems displaced by gasification would tyically be used for back-up. Storage requirements Application in the extreme climates common to Alaskan villages may require up to 9 months worth of wood storage. Thermodynamic efficiency 65 percent to 85 percent conversion of fuel feedstock to usable energy form. page 90 Net energy N/A 5.2.3 - Costs Capital N/A Assembly and installation N/A Operation N/A Maintenance and replacement N/A Economy of scale Will be limited by proximity and difficulty in harvesting of forest reserves. E.5.2.4 - Special Requirements and Impacts Siting - directional aspect, land, height Gasifier will need to be close to wood source to reduce cost of transport. Resource needs Renewab le Wood as well as other cellulosic biomass can be utilized. Other biomass includes: straw, almond shells, and peach pits, for example. Non-renewab le N/A Construction and operating employment by skill Skilled construction and operating personnel are required. E.5.3 page 91 Environmental residuals Solids: ash, tars Health or safety aspects Low Btu gas is flammable and generally contains high levels of toxic carbon monoxide. 5.2.5.- Summary and Critical Discussion Wood gasification is presently under development for application to Alaskan village diesel generators in an AVEC administered program. Anticipated program progress indicates a possible infield demonstration no earlier than 1986, with commercial service introduction perhaps by 1988. At present, success of the development program is not certain, thus availability of wood gasifiers for diesel electric application is uncertain. Existing gasifier designs as applied to provide heating fuel would appear to offer no: benefit over direct wood fired heating. - Biogas Generation £.5.3.1 - General Description Biogas (two-thirds methane and about 600-700 Btu/scf) can be produced from organic waste. In a biogas generation system, heat is used to promote anaerobic bacterial digestion. Figure E£5.3.1 depicts the biogas generation process. Anaerobic fermentation of organic products results in methane, carbon dioxide, hydrogen, traces of other gases, and the production of some heat. The residue remaining is hygienic, rich in nutrients, and high in nitrogen. Potentially harmful organisms are killed by the absence of oxygen during the fermentation process. There are over 50,000 small scale biogas producers in rural India and over half a million reported in mainland China. A demonstration unit in Alaska works on crab processing wastes. The technology is quite well established. Units range from “one cow" size (20,000-30,000 Btu/day) to over 3 billion Btu/day. page 92 £.5.3.2 - Performance Characteristics Energy output Unless organic wastes (other than human) are available, production for a village will be quite limited. For example, based on a population of 100, an average human waste of 3 pounds/day, 11 percent solids in that waste, 84 percent of solids being volatile (gas producing), production of 5 cubic feet of biogas at 600 Btu/cubic foot per pound of volatile solids, the theoretical biogas energy production is about 80,000 Btu/day, equivalent to a heat content of six-tenths of a gallon of diesel fuel per day. Biogas generators can be designed for continuous or batch (4 days - 2 weeks) operation, depending on the mode of digester loading utilized. The biogas producing digestive activities are optimal in two temperature ranges: 85°-105° and 120°-140°F, although digestion will occur from freezing to 156°F. Fermentation, however, is less stable in the higher of these two ranges and, consequently, the biogas units should usually be designed to be maintained in the lower optimal range. Typically, biogas generation in lower 48 climates requires one-third to one-half of the enegy content of the gas generated to heat the process. This efficiency of 50-67 percent could drop to zero in severe Alaska climates. Reliability Need for backup Fossil fuels displaced by the gasifier would typically be used for backup Storage requirements The tank will permit a modest amount of gas storage in the void above the digesting wastes. 7 Thermodynamic efficiency 65 percent to 95 percent conversion of fuel feedstock to usable energy form. Net energy N/A page 93 GAS OUT WATER IN ORGANIC SLURRY FERTILIZER WASTE IN i SLURRY BIOGAS DIGESTER PADDLE OR OTHER AGITATION BIOGAS GENERATION FIGURE E5.3-! page 94 E£.5.3.3 - Costs Capital N/A Assembly and installation N/A Operation N/A Maintenance and replacement N/A Economies of scale N/A E.5.3.4 - Special Requirements and Impacts Siting - directional aspect, land, height The waste feedstocks are water based slurries which are subject to freezing in transport lines. Consequently, the digester facility should be located as near to the waste source as possible to minimize exposure to cold temperatures. Resource needs Renewab le Appropriate feedstocks for consideration are manure, fish and shellfish wastes. Non-renewab le N/A Construction and operating employment by skill Skilled construction and trained operating personnel are required. Environmental residuals Solids: inert sludge page 95 Health or safety aspects The gas is highly flammable. E.5.3.5 - Summary and Critical Discussion Cost per million Btu or kWh Lower 48 costs of a manure based commercial unit is projected at $10,000 per 1,000 scf/d of capacity in smaller sizes to $3,000 per 1,000 scf/d for units in the range of 100,000 scf/d. Resources, requirements, environmental residuals per million Btu or kWh. N/A Critical discussion of the technology, its reliability and its avai lability. The application of biomass digesters is highly dependent upon the availability and reliability of adequate feedstock materials. Seasonal waste supplies will present problems of storage for produced gas, (unless allowed to freeze and rethawed) as the digestion process proceeds regardless of demand for gas. Large quantities of waste must be available if a spark ignition engine generator of reasonable size is to be fueled with biogas. Assuming 500 Btu/scf gas production from a digester with an efficiency of 75 percent, and a heating value of 5,000 Btu/1b for the waste in the as produced condition, a 100 kW continuous generator output from a 20 percent efficient machine would require a continuous input of 256 lbs of waste per hour (93 tons per month), exclusive of the gas requirement to maintain digester tank temperture. Overall, application to Alaskan village conditons would appear to be worth considering only under exceptionally favorable circumstances. £.5.4 - Waste Fired Boiler £.5.4.1 - General Description While refuse (waste) can be used as an alternate boiler fuel, large quantities are required on a continuous basis to justify the large capital investment for a facility providing either heat or power. As only the Anchorage (and possibly Fairbanks) area approaches the production quantities required, this option is dismissed for the villages. page 96 E.5.5 - Peat £.5.5.1 - General Description Peat is an early stage in the transformation of vegetation to coal and results from the partial decomposition and disintegration of plant remains in the absence of air. Peat is generally formed in water bogs, swamps, and marsh lands. Generally, peat is low in nitrogen, sulfur, and ash. A study to estimate Alaskan resource potential was recently performed for the State of Alaska, Division of Energy and Power Development. Numerous peat deposits were located and outlined in the study. Undrained bog peat usually contains between 92 and 95 percent moisture, but moisture is reduced to about 25 to 50 percent when peat is harvested (by large earth moving equipment) and air dried. At these reduced moisture levels, the bulk density of the resulting peat is about 15 to 25 pounds/cubic foot and its heat value is approximately 6,200 Btu/pound. Wood is less difficult to gather and burn and contains a greater heating value per pound. This has kept peat out of the energy market in Alaska. E—.5.5.2 - Performance Characteristics Performance is similar to burning low-grade coal. E2553 — Costs Peat-fired boilers require larger furnace volumes than are required for gas, oil, or even low grade coal. Consequently, initial cost will be greater. The harvesting and drying operation is also more equipment and fuel intensive than coal. Investment and operating costs will, therefore, be higher than for coal-fired plants on a per kilowatt of capacity/kilowatt-hour generated basis. page 97 E.6 - OTHER TECHNOLOGIES £.6.1 - Binary Cycle for Electrical Generation E.6.1.1 - General Description Thermodynamic and engineering processes involved The binary conversion process requires only heat quantity (heat energy/unit time) and quality (temperature) to provide power. A heated primary fluid of insufficient quality for direct use in electrical production passes through a heat exchanger to transfer heat to a working fluid. The working fluid has a lower boiling point than water and is vaporized in the heat exchanger. The vaporized working fluid then expands through a turbine, or in a cylinder-piston arrangement, is condensed, and returns to the heat exchanger. The primary fluid is returned to its heat source following heat exchange. Figure £6.1-1 shows a generalized binary cycle. Current and future availability Binary cycle generation equipment in unit sizes suitable for village applications are not expected to be available until the late 1980's. E.6.1.2 - Performance Characteristics Energy output Quality - temperature, form Electricity Quantity A function of unit size Dynamics - daily, seasonal, annual Power can be generated whenever the heat source is avai lab le. Reliability Need for back-up When powered by waste heat, binary cycles are typically used for peaking. If used for base loads, the binary-system would typically be backed up by the fossil system it displaces. Storage requirements Fuel storage requirements are those of the heat source technology. page 98 Thermodynamic efficiency - around 10 percent to a reported 27 percent - the organic Rankine diesel or Homing binary cycle can increase plant output power by 15 percent Net energy 3-10 units in to 1 unit out E.6.1 3 - Costs Capital N/A Assembly and installation N/A Operation N/A Maintenance and replacement N/A Economies of scale Commercially utilized systems range from 1 to about 100 kW E.6.1.4 - Special Requirements and Impacts Siting - directional aspect, land, height Units are relatively small and light and require only an enclosure and connection to the (nearby) heat source. Resource needs Binary cycles per se have no resource needs as. heat is provided from some other resource technology profiled herein. Hence, solar geothermal, nuclear, and radiation, as well as any combustion material, such as wood or coal are potential fuels. Construction and operating employment by skill Initial village installations would involve factory personnel for most work. Operation can be relatively unattended, although a qualified mechanic should be available. Page 99 PRIMARY FLUID WORKING GENERATOR HEAT EXCHANGER CONDENSER COOLING FLUID GENERALIZED BINARY CYCLE FIGURE E6.I-! page 100 Environmental residuals Closed binary cycles in and of themselves cause no environmental residuals; normal residuals are a result of the heat source. Seal failure would cause leakage of the binary working fluid. Health or safety aspects Seal failures may cause release of gases which are generally toxic and/or flammable. E.6.1.5 - Summary and Critical Discussion Cost per million Btu or kWh N/A Resources, requirements, environmental residuals per million Btu or kWh. No resources are required other than those required for the source of heat (typically diesel for engine-generators) nor are any additional environmental residuals created. Critical discussion of the technology, its reliability and its avai lability There are both domestic and foreign suppliers of appropriate size binary cycle systems and product development is being vigorous ly pursued. Binary cycles for village electrical application could involve so-called diesel "bottoming" - use of exhaust gas heat. Both Rankine and Stirling cycle equipment in the less than 100 kW range are available and at least two manufacturers have sought funding and assistance for an Alaska demonstration. Binary bottoming cycle equipment is in operation in the Trans-Alaska Pipeline utilizing waste heat to produce electricity. E.6.2 - Conservation £.6.2.1 - General Description Thermodynamic and engineering processes involved Conservation measures considered here are mainly classified as "passive". Passive measures are intended to conserve energy page 101 without any further electrical, thermal, or mechnical energy input. Typical passive measures are insulation, double glazing or solar film, arctic entrances and weather stripping. Energy conservation characteristics of some passive measure degrade with time, which must be considered in the overall evaluation of their effectiveness for an intended life cycle. Other conservation Measures include improvement in efficiency of utilization devices (such as motors) and "doing without", energy by disciplines (turning off lights, turning down thermostats). Current and future availability Passive measures are commercially available and increasing in use all over the United States due to the rapidly escalating cost of energy. E.6.2.2 - Performance Characteristics Energy output Quality - temperatures, form No energy output per se; rather a reduction of energy types input. Quantity See above Dynamics - daily, seasonal, annual Passive conservation measures "operate" year round Reliability Need for back-up None required Storane requirements None required Thermodynamic efficiency Not appropriate Net energy Not appropriate page 102 E6205) |= COSts Capital Residential installations run from several hundred to several thousand dollars. Assembly and installation See above Operation None Maintenance and replacement Effectively maintenance free; 10-15 year life for major methods Economies of scale Amenable and appropriate to single dwellings or large industrial complexes. E.6.2.4 - Special Requirements and Impacts Siting - directional aspect, land, height No special requirements Resource needs Renewab le Solar insolation for passive solar methods Non-renewab le Materials used for conservation modes employed. Construction and operating employment by skill Can often be installed by the resident; locally specialized services (for example, insulation skills) may be employed. No operation required. Environmental residuals Generally none. Excessive sealing of structures can produce toxic or carginogenic gas concentraitons due to inadequate ventilation. page 103 Health or safety aspects Care should be taken to assure proper air change rates for occupant health. E.6.2.5 - Summary and Critical Discussion Cost per million Btu or kWh N/A Resources , requirements, environmental residuals per million Btu or kWh. N/A Critical discussion of the technology, its reliability and its avai lability. Residences generally require the availability of energy at all times. Before 1973, the cost of household energy was 3 to 10 percent of total annual expenses; now that percentage has soared to perhaps 40 percent. Although some dynamic measure (notably solar energy) merit consideration in this class of structure, the prime emphasis should be on passive energy conservation measures. As a whole, this market is not geared to sophisticated or costly equipment or to any measure that requires special operating or maintenance procedures or attention. Generally, simplicity and low cost, with moderate energy benefits, should be pursued. The State of Alaska has high interest in energy conservation by weatherization (passive conservation), particularly for residences. The State has had a $5,000, 5 percent loan program for upgrading residences for conservation of energy but recent (1983) legislative actions have put the future of this program in doubt. F - SAMPLE VILLAGE TECHNOLOGY ASSESSMENT page 104 The following illustrates application of the Cost and Resource Criteria of the Technology Screening Methodology discussed in Section C, as applied to the village of Elfin Cove. (1) Coal Fired Steam Costs: Resources: (2) Wood Fired Steam Costs: Resources: Investment - maximum expected load less than 1 MW: investment will probably exceed $10,000/kW - 0 pt. Operating - expect $100,000/yr; O&M assume 50 kW average load (0.4 GWh); $250,000/GWh = 0 pt Fuel - shipping costs and purchase at Healy mine expected to result in $150 - 200/ton price (or about the same as oil for the same energy); multiply times estimated heat rate of 20,000 Btu/kWh, divide by 15,000 for diesel; use factor of O pt. Energy - coal is not widely available in bulk to Elfin Cove; 0 pt. Socioeconomic - no infrastructure exists to staff, run, repair coal- fired steam plant; 0 pts. Investment - costs expected to be 20 percent higher than coal; 0 pt. O&M - operating costs expected to be 10 - 20 percent higher than coal; 0 pt. Fuel - cost of gathering pe processing wood: present price per cord is roughly equal to $8/10°Btu (or 75 % oil) no outside market, some sensitivity to oil price for transport - 1 pts. Energy - wood available in surrounding area, which is National Forest with no road access to other harvest sites - 3 pts. Socioeconomic - as with coal, no infrastructure to run plant; O pts. page 105 (3) Geothermal Costs: Investment - initial costs will likely exceed $10,000/kW; 0 pt. Operating - O& costs will be as significant as with coal or wood - can expect well operating problems; 0 pt. Resource: Energy - no known geothermal in Elfin Cove area Socioeconomic - no infrastructure to build, operate or repair plant exists; 0 pts. (4) Diesel ; Costs: Investment - available capacities well matched to load, $1,000/kW; 4 pts. O&M - annual costs for diesel approach $100,000/GWh; 1 pt. Resource: Energy - Oil fuel imported; 7 pts. Socioeconomic - some diesels presently operated; 2 pts. (5) Gas Turbine Costs: Investment - approaches $1,000/kW if 800 kW capacity required, but for Elfin Cove, inadequate load throughout study period; 0 pts. O&M - O&M costs will be higher than diesel because of need for Tabor required for hot-section maintenance; 0 pts. Fuel - lower efficiency at part load will increase per kWh fuel costs over diesel; 0 pts. Resource: Energy - imported fuel; 7 pts. Socioeconomic - questionable support skills for O&M; 1 pt. (6) Hydroelectric Costs: Investment - Kalakaket Creek estimated $5,000 to $7,000 per kW; 1 pt. O&M - unattended plant expected, perhaps $2,000/year expense and — $500 annual replacement for 60 kW plant - perhaps $3,000/GWh; pts. (6) (7) (8) Hydroelectric (contd) Wind Photovoltaic Costs: Resources: Costs: Resources: Costs: Resources: page 106 Fuel - none; 3 pts. Energy - Creek freezes in winter and may run dry in summer ; 3 pts. Socioeconomic - limited skills needed for unattended plant - diesel operator level; 2 pts. Investment - installed costs per rated kW of at least $5,000/kW; with unknown wind resource of Elfin Cove cost could reach $10,000/avg. kW; 1 pts. O&M - expect more maintenance than with hydro - estimate $5 - $8,000 + $1,000 replacement year (for 30 kW unit); at 20 percent capacity factor = $35,000/GWh or 62¢/kWh; 2 pt. Fuel - none; 3 pts. Energy - Elfin Cove wind resources are unknown in spite of weather station in the village. Existing station is sheltered and data is not representative of area. Gulf of Alaska area should have good wind resources; a generous 3 points Socioeconomic - city should be able to support a WIG; 2 pts. Investment - over $20,000/peak kilowatt expected, even with storage removed; O pts. O&M - estimate ce eee ae or perhaps $500/year; replacement cost = $1,000, thus $1,500/yr; if 25 percent capacity factor (CF) on devices - (include clouds and rain, derate for latitude in winter), yields $20,000/GWh; 3 pts. Fuel - none; 3 pts. Energy - Limited by night/day, cloud cover, winter sun - no storage assumed for system, unreliable source; 3 pts. to be generous Socioeconomic - no problems foreseen except with some of the sophisticated electronics = 2 pts. (9) Diesel Waste Heat (10) Electric Resistance (11) Passive Solar Costs: Resources: Costs: Resources: Costs: page 107 Investment - Due to very small winter population in Elfin Cove, the energy available from any practical system would be so small that the per-user cost would be excessive, likely beyond $3,000 per user and perhaps as much as $5,000; 1 pt. O&M - annual O&M costs expected to be approximately $2,000/year and replacement of $500 = $2500; heat production - est. 25 percent "capacity factor" or 0.03 GWh of heat/year = $/GWh of 83,000; 1 pts. Fuel - none; 3 pts. Energy - within the limits of the generating plant capacity, BET Eebility is excellent with the system already in place and doubtfully fully loaded; 9 pts. Socioeconomic - capable of support; 2 pts. Investment - 4 pts. O&M - 4 pts. Fuel - electricity is most expensive form of energy available; 0 pts. Energy - generating capacity is limited - off peak energy available in some quantity but not enough to heat more than a few homes intermittently; 2 pts. Socioeconomic - no problems foreseen; 2 pts. Investment - retrofit to existing homes expected to cost upwards of $10 - $15,000, therefore, not considered; new homes might include passive design features which would be useful in summer at less than $5,000; 2 pts. for new homes only. O&M - generally negligible for operation, house replacement normally js not considered by homeowner; 4 pts. (11) Passive Solar (12) Wood (13) Coal (contd) Costs: Resources: Costs: Resources: Costs: Resources: page 108 Fuel - none; 3 pts. Energy - northern latitude limits winter usefulness; only new homes considered; 3 pts. Socioeconomic - although lifestyles might be altered, no problems seen in absorbing technology if included in new home design package; 2 pts. Investment - wood stove kits range from $50 (to modify oil drums to short Tife/high efficiency systems) up to $1,000; 4 pts. O&M - periodic cleanout, flue cleanout required; 3 pts. Fuel - wood estimate at $150/cord is approximately the same price as oil, but its price will not escallate; 2 pts. Energy - adequate supplies throughout the area; residents must take care against violating Nationa Forest regulations when harvesting; 7 pts. Socioeconomic - established heating method; 2 pts. Investment - stove designs available at costs up to $10,000 for fully automated feed and ash discharge; 2 pts. O&M - similar to wood; 2 pts. Fuel - cost from Nenana approaches the price of oi]; 0 pt. Energy - no existing shipping arrangements - none expected; 0 pts. Socioeconomic - no existing system in village for large scale handling, warehousing, etc.; 1 pt. (14) O41 (15) Coal Gasification (16) Wood Gasification Costs: Resources: Costs: Resources: Costs: Resources: page 109 Investment - Existing stove designs in use and available at $1,000 to $2,000 per unit; 3 pts. O&M - minimum annual expenses replacement and maintenance less than $1,000/yr; 4 pts. Fuel - oil; 1 pt. Energy - imported; 7 pts. Socioeconomic - existing system; 2 pts. Investment - small scale requirements from a large scale technology; 0 pts. O&M - large scale expenses for commercial size equipment; 0 pts. Fuel - poor efficiency compared to direct coal fired steam; 0 pts. Energy - none available; 0 pts. Socioeconomic - no existing capability to support technology in city; 0 pts. Investment - Marenco estimate for 250 kW gasifier diesel system approaches or exceeds $2,000/kW with all equipment; 2 pts. O&M - full time operator required, plus fuel handler - 2 men x 168 hr/wk x 52 wks/yr x $20/hr = $350,000 + add perhaps $100,000 for maintenance = $450,000. Generation @ 70 percent C.F. = 1.5 GWh, or $300 ,000/GWh; 0 pts. Fuel - wood, as before; 0 pts. Energy - availability as before; 7 pts. Socioeconomic - no capability to operate gasifier exists, no service structure exists; 0 pts. (17) Biogas (18) Waste Fired Boiler (19) Peat Costs: Resources: Costs: Resources: Costs: page 110 Investment - as minimal materials are available as feedstock, output will be very small for initial response; 0 pts. O&M - minimal expenses, but still significant compared to expected output; 0 pts. Fuel - were it available, nearly free; 3 pts. Energy - too little to make it worthwhile; 0 pts. Socioeconomic - systems are simple, within city capabilities; 2 pts. Investment - modular systems are available, but in sizes much larger than can be supported. 40 tons/day will produce approximately 4,000 lbs/hr of low pressure steam around the clock - and facility will cost close to $3 million or $300,000 per GWh of heat; therefore, use 0 pts. O&M - full time operator required, plus significant maintenance is typical; 0 pts. . Fuel - refuse/garbage must be collected from all homes and sorted for most systems; 0 pts. Energy - population is inadequate to support any economical waste to energy facility; 0 pts. Socioeconomic - operation and maintenance skills, service support existing in village or nearby are inadequate; 0 pts. Investment - boilers are more expensive than for wood; harvesting, drying and storage equipment will not be cheap; 0 pts. O&M - operating costs will involve one full-time and probably one part-time employee (1/2 man) per shift, plus significant regular maintenance, high capital cost results in high replacement expense; 0 pts. (19) Peat (contd) Costs: Resources: (20) Binary Cycle Generator Costs: Resources: (21) Conservation Costs: Resources: page 111 Fuel - assuming location is nearby, harvesting labor and fuel used for drying will be significant expenses, particularly for small operation. Boiler efficiency is also expected to be low; 0 pt. Energy - No known reserves of peat in the Elfin Cove area; 0 pts. Socioeconomic - No existing trained workforce to gather peat, no source of equipment or maintenance; 0 pts. Investment - initial costs are very high - often approach and likely to exceed $10,000/kW for equipment only; 0 pts. O&M - some maintenance or inspection expected on a daily basis - but Minimal; 3 pts. Fuel - "Free" energy; 3 pts. Energy - Little energy avaiable in Elfin Cove probably not enough to cone tler for binary cycle application; 1 pt. Socioeconomic - runs basically unattended; as unit would not be a critical item adequate support should be available; 1 pts. Investment - minimal investments are expected to produce major savings in many Elfin Cove homes; 4 pts. O&M - annual inspection generally will be adequate; 4 pts. Fuel - none; 3 pts. Energy - waste energy savings; 9 pts. Socioeconomic - minimal instruction would be all that is required - materials generally easy to obtain and apply. (Major fixes such as wall/ batt insulation are not being considered in this instance but are also possible.) 2 pts.