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HomeMy WebLinkAboutGrayling Reconnaissance Study of Energy Requirements & Alternatives 4-1981RECONNAISSANCE STUDY OF ENERGY REQUIREMENTS AND ALTERNATIVES FOR GRAYLING Report Summary April, 1981 by Northern Technical Services and Van Gulik and Associates Anchorage, Alaska ALASKA POWER AUTHORITY RECONNAISSANCE STUDY OF ENERGY REQUIREMENTS AND ALTERNATIVES FOR GRAYLING Report Summary April, 1981 by © Northern Technical Services and Van Gulik and Associates Anchorage,Alaska ERRATUM In the Introduction to this summary report, the second para- graph, first item on the first page should read as follows: . It was necessary to assume that the cost of diesel fuel would increase at a rate of 3.5% per year above the inflation rate. Introduction As you read this report, you will-see that the results generally favor energy conservation (including the use of waste heat from diesel generators) with existing systems, as opposed to conver- sion to renewable energy alternatives. These results do not mean that renewable energy sources cannot be used in your com- munity, but rather that, under the conditions and assumptions used in the study, the alternatives appear to be at least as expensive as diesel generation as well as somewhat higher in risk. The above-mentioned conclusions are best estimates based on reconnaissance work in your area. This work was essential to predict the cost using other sources of energy. The conclusions are based on past experience, present costs (of fuel, materials and labor) and estimates of what might reasonably be expected to occur in future years. Some of the assumptions which had to be made in order to perform the economic analysis of the different alternatives include the following: * It was necessary to assume that the cost of diesel fuel “would increase at a rate of 3.5% per year dbove The inlets rake - * It was necessary to assume that the growth of the com- munity's population would increase at roughly the same rate that it has in past years and that the increase in community energy consumption would follow that rate of growth. * It was necessary to assume that the costs associated with maintenance and operation of an alternative energy conversion system would be an integral part of the annual cost. It was necessary to base cost estimates on present (state-of-the-art) technology since it is virtually impossible to predict future technical advances in sys- tems for the conversion of alternative energy resources into useful electricity. It was necessary to assume that most people would pre- fer continuously available electricity and that they would probably not be ready to accept the inconvenience of intermittant power (for instance, doing without elec- tricity when there was too little wind for their wind generator to produce electricity.) It was necessary to assume that most people would prefer that a central "utility" provide them with elec- tricity rather than installing and operating their own system. If any of the above assumptions prove to be inaccurate or if their validity changes -- and this could easily happen in future years as the costs of the existing systems continue to increase -- alternatives which presently do not appear to be economically or technically feasible may become real options. Some examples of changes which could result in more favorable economics for the use of energy alternatives include the following: Fuel prices in the community could increase at faster rate than that assumed in this investigation. People in the community might decide to maintain and operate alternative energy conversion systems themselves, perhaps even trading their services within the community for subsistance commodities rather than cash. New inventions or improvements on present technology might make the cost of using an alternative energy source much less expensive than is presently indicated. What this report means, then, is that * Energy conservation is certain to lead to some savings of energy and money. Energy conservation measures will continue to minimize costs in future years, no matter what sources of heat and electric power are in use. * There are some alternatives (presented in the summary, next section) which appear to be worthy of further investigation at this time. * It will be necessary to continue to look for ways to make the use of other alternative energy sources practical. It is important that you, the people who live in the community, and others with an interest in the community and the region (including government leaders and planners), read this report with the previous points in mind. You are most familiar with your region and can, with appropriate technical and financial support, make the best decisions for your energy future. The authors of this report and the Alaska Power Authority hope that you will take the time to comment on the information presented here and point out any alternative ideas. In this way, we can be assured that future planning for energy projects will lead to the best possible options for your community. It should be noted that the information presented here is extracted from a much more detailed report "Reconnaissance Study of Energy Requirements and Alternatives for Togiak, Goodnews Bay, Scammon Bay and Grayling" and that additional detailed information is available. The Community of Grayling Grayling is an interior community of approximately 181 people. The population is mostly native (Athabascan Indian). Grayling is located on the west bank of the Yukon River 20 miles north of Anvik and is accessible by air on a year-round basis. The main air hub nearest the town is Aniak, with 5 weekly round trip flights between Aniak and Grayling. Commercial air transporta- tion from Anchorage to Aniak is via either Bethel or McGrath. Surface transportation to Grayling is by river boat in the summer months and by snowmachine or dog team in the winter. The village of Grayling was originally located at Holikachuk (var. Holikachat) on the nearby Innoko River but was moved beginning in late 1962 for a variety of reasons including: o frequent flooding of the old village site, o fuel sources (brush and trees) depleted, resulting in longer distances to be traveled to obtain firewood, o desire to be closer to summer fish camps on the Yukon, o improved hunting and trapping, and \ o improved freight costs. The economy at Grayling relies heavily on subsistence activities including hunting, trapping, fishing and harvesting of local timber for heating fuel. Cash income is generally obtained by leaving the community, mainly in the summer, to work as commercial fishermen and cannery workers or laborers in other parts of the state; through the sale of pelts and local craft items (such as bead work and baskets), jobs at the local schools, and a native-owned village coop store; and from public assistance payments. The average annual per capita income from all sources was estimated to be $1,825 in 1970 and $1,956 in 1977. There has been minimal economic development at Grayling between 1977 and 1981, and the annual income is not expected to have increased significantly in that period. There is presently an average of 3.8 people per household, making annual household income approximately $7,432. The village population has been quite stable since 1890 and has shown a slight growth trend from 1940 to 1980. Grayling Energy Use The energy input and end use for Grayling is shown in Table l. The data represented in this table is based on 1979 energy consumption levels which is the last year for which complete data are available for this study. The major oil consumers in the village are the Alaska Village Electric Co-op, the BIA school, and small commercial buildings which use oil primarily for heating. Other users include the pump house, where oil is used for water heating, and the National Guard (small amount). Propane is used in the village primarily for cooking. Gasoline is used for snowmobiles, fishing boats, and airplanes. The major portion of the home heating is derived from burning wood which is locally available either from driftwood on the bank of the Yukon or from the forest which surrounds the village. This resource significantly reduces the amount of oil used in the village for heating compared to the coastal communities of this study. The amount ot wood shown in Table 1 was calculated assuming that the average home in this region (with 14,000 heating degree days) would consume approximately 1000 gallons of fuel oil per year. It was assumed that wood is burned at a combustion efficiency of 50%. The AVEC generators at Grayling had an energy conversion effi- ciency of 18.9% for gross generation of power. This efficiency ENERGY INPUT AND END USE FOR GRAYLING Numbers in parentheses () are (10° Btu) ENERGY FORM DIESEL/- GASOLINE/ END #1 OIL AVGAS PROPANE WOOD ELECTRICITY | USE GALLONS GALLONS POUNDS CORDS KILOWATT HOURS | Alaska Village 30,7001 40,8002 L Electric Cooperative (4144.5) (139.3) Residential and 7,100 15,0003 330 68,1606 Small Commercial (958.5) (325.0) (6600.0) (232.3) (Space and water 4 heat and domestic) Municipal and other 3,300 | 46,3006 public (445.5) (158.0) (non-transportation) Transportation 40,0005 (5000) BIA School 9,700 78,0006 (non-transportation) (1309.5) (266.2) | NOTES: 1 Gross generation from 30,700 gallons was 233,300 Kwh tor conversion etticiency ot 19.2% 2 Power consumed by the utility tor station service (lights, tuel pumping, etc) and system distribution losses 3 Propane used solely for cooking 4 See Appendix B for calculation of wood consumption. 5 Consists of 18,000 gallons 100/130 aviation tuel (aireratt), 22,000 gallons 80/87 avia- tion tuel (snow machine) 6 Net utility electrical sales in 1979 were 192,500 Kwh. TABLE 1 should increase with the addition of the new school. Distribu- tion losses at Grayling were 17.5%. The total amount of waste heat that can be recovered in the vil- lage consists of heat from the diesel generators, heat lost in the home heating combustion process and energy losses through * the village building envelopes. It is estimated that approxi- mately 50% of the input energy to the diesel engines can be captured in a waste heat capture process. Existing Power Facilities All electricity in Grayling is diesel generated. Information on the community's generators is summarized in the following table: ~ were er eye -_—_—_—— VILLAGE OWNER | NO. SIZE MAKE/MODEL VOLTAGE TOTAL Grayling AVEC 1 150 Allis Chalmers 120/240,19 300 . Type BGKB | AVEC 2 75 Allis Chalmers 120/240,198 ; Type BGKB i : BIA 1 25 Fairbank Morse 120/240,18 BRKL12 BIA 2 25 Kohter 25COT16 PHS ° 1 25 Existing Heating Facilities The largest single consumer of fuel for space heating in the community is the school. The BIA school uses oil-fired boilers to heat water for distribution to its circulating hot water system. Water for domestic use and showers is heated through neat exchangers from the same boilers. The new state high school, which is expected to be operative in the 1981-82 season, will have a heating system which utilizes both oil-fired boilers and an oil fueled hot air furnace. The school will .have an additional oil-fired boiler to heat domestic hot water. This large consumer of oil for hot water heating systems is a prime candidate for receipt of waste or cogenerated heat from power production. In Grayling, most residential heating is accomplished by means of a variety of wood stoves, including barrel stoves and cooking stoves. Summary of Existing Conditions Grayling is presently using local wood for much of the residen- tial space heating. It is estimated that approximately 290 cords are presently used by the entire community in the course of one year. This heating fuel is generally not a drain on local cash resources. Although in past years the village moved from an area in which wood supplies were being depleted, the present location on the Yukon River allows driftwood to be harvested in addition to local timber; it is likely that because of the availability of driftwood, local timber resources will be depleted at a slower rate. In most Alaskan communities where wood is harvested for fuel, it can be expected that residents will be required to travel increasingly greater distances to obtain standing and fallen dead trees, and this could become the case in Grayling even with the continued supply of driftwood. Approximately 30,700 gallons of fuel oil per year are consumed for electric generation for all sectors in Grayling. The annual residential consumption is about 68,160 KWh out of a total community consumption of 233,260 KWh. The peak demand on the system is presently 65 KW. Electricity costs consume an average of 8% of a household's cash income. Heating fuel may consume as much as 9% or more of the cash income of an older person who is unable to harvest wood supplies or who may be living on a smal- ler cash income than the village average. The homes in Grayling would benefit from a weatherization pro- gram. There is a marked variety in the quality of construction from one home to the next; some of the homes are in relatively good condition, while some are in need of insulation and mea- sures to decrease infiltration. Known Projects Which Will Influence Grayling's Future Energy Needs Housing and Urban Development officials have indicated that design and construction of twenty new housing units would be initiated beginning in Federal FY 1981 with construction; to continue possibly through FY 1984. For energy projection purposes it was assumed that these units would be occupied during 1984. During field reconnaissance the new state high sdchool under construction was inspected by field personnel. The Iditarod School District indicated that the school would be in use by the fall of 1981. Population Growth Best estimates of the population growth of Grayling indicate a population of around 230 people by the year 2000 (Figure 1). ' Community Meeting A community meeting was held in Grayling on October 21, 1980. Initial notification of the meeting was by radio (over the radio station KNOM) and by telephone conversation with Tom Maillelle, the acting Mayor of Grayling. ‘ The meeting was attended by about 15 people. Not everyone signed the register, but those who did were Henry Deacon, Joseph Maillelle, Sr., Wilfred Deacon, Tom R. Maillelle, William Painter, Eleanor R. Deacon, and Lancelot Hughes. POPULATION (Y) 240 -- GRAYLING a YY 7 Pl 200 -+- Ai 160 + 120 -- x X ACTUAL DATA, ISER & U.S. CENSUS —-——-— PROJECTION eal IL 40 +- : 10 20 30 40 50 60 70 YEARS FROM 1930 (xX) 0 =} fff} ppp 1930 1940 1950 1960 1970 1980 1990 2000 YEAR FIGURE 1. The energy reconnaissance project was discussed by Don Baxter, of the Alaska Power Authority (APA), and additional information added by Paul Oliver of VanGulik Associates and Patti DeJong of Northern Technical Services (NORTEC). Information was solicited regarding local resources such as a nearby coal outcrop and a suspected "geothermal" site. Those present at the meeting were familiar with the coal outcrop and discussed a spot where snow melted rather than accumulated. No one seemed to be really familiar with the area where this warm spot was said to exist. (One person offered to take project personnel to those sites on a snow machine the next day, but the snow machine was being repaired and the trip had to be cancelled.) The people at the meeting were especially concerned about the high cost of electricity. Fuel costs in Grayling appear to be less of a problem than electricity costs, since wood stoves meet much of the residential heating demand. There were no objections to the idea of a small scale coal development, but if this option is pursued further, it will be necessary to more fully discuss the positive and negative impli- cations of this alternative. Most people were enthusiastic about hydroelectric generation using Grayling Creek. Wind was another topic which elicited a favorable response, but most agreed there wasn't "enough" wind at the townsite. It was suggested by one person that a wind generator could be located atop the hill directly west of the town since that area was much windier than the townsite. In addition to this meeting, many other Grayling residents were consulted throughout the course of the reconnaissance work. Everyone contacted was quite aware of the high cost of electri- city, and all were eager to find some means of reducing costs. Alternative Energy Resources for Grayling Energy Conservation Energy conservation is usually one of the most cost effective methods for reducing energy consumption and costs. Energy conservation herein means retro-fitting or modifying any existing heat process. This can be done by increasing combus- tion efficiency, or by reducing the losses from the heat using process. Villages in western Alaska can-benefit from the energy conservation practices which relate primarily to weatherization and improved combustion efficiency. The homes in the study villages averaged 750 square feet in size, were single story, built on piles, with exposed floors. Some of them had skirts around the piling to reduce cold air circulation under the building. If these buildings are occupied by a family present during the day, then oil consumption is typically be on the order of 150 gallons per month in the colder months, resulting in heating costs close to $300. The technology to reduce energy consumption in oil heated homes exists and could be economically applied. The requirements are simple and there should be no environmental or health impacts. Generator Waste Heat Total AVEC generator waste heat at Grayling is about 3,350 x 106 Btu/year. Of this amount, about 2,070 x 106 Btu/year are recoverable. This amount exceeds the 785.7 x 106 Btu/year of heat output from the BIA school's boilers. A second customer for the waste heat may be the state high school. Transmission distances between the generator plant and these facilities make sale of waste heat to the schools slightly less convenient (and More expensive) than elsewhere, but because of the large excess of heat potentially available this option is worthy of further detailed consideration. Wind The wind recording station nearest Grayling is Aniak. While local topography will greatly influence the wind direction and magnitude, data from Aniak may be used as a rough indicator of the wind resource at Grayling. Mean monthly winds at Aniak for the period from 1948 to 1970 are as follows: Month Mph January 6.44 February 7.13 March 7.36 April 7.47 May 6.90 June 6.33 July 5.52 August 5.98 September 6.44 October 6.67 November 6.44 December 5.52 Mean Annual 6.5 The people of Grayling confirm that the town experiences only minimal wind but point out that areas atop the hill adjacent to the community do experience higher winds. Wind at Grayling is not considered to be a first alternative energy source. Should other alternatives prove unfeasible, wind measurements made at several key locations could define a wind resource superior to that described. Hydro Grayling Creek, with a drainage area for the proposed dam site of 24 square miles, was the subject of this analysis. U.S.G.S. . Coefficients Flow Mean annual low monthly 0.2 cfs/mi2 7 cfs Mean annual 1 34 Mean annual peak 10 340 The Alaska Power Administration measured a stream flow of 200 cfs in the village, a point far below the dam site which includes a south fork of Grayling Creek, having a total drainage area of 88 sq. mi. This converts to a unit runoff of 2.3 cfs/mi2 which falls within the expected range between the mean annual and mean annual peak flow. However, it does seem slightly low since the flow was observed to be slightly higher than normal due to recent rains, approximately four times the observed August flow or 800 cfs. This converts to a mean annual peak runoff of 9 cfs/mi2 which is very close to the assumed unit runoff of 10.cfs/mi2. The Administration report also states that a local resident indicated the lowest flows normally occurred in September. This is contrary to the generalized regional hydrograph and apparently was ignored by which, through the hydrocapability curve, indicated lower flows should be expected from October to March. Although the creek appears to have a reasonably good potential for hydroelectric generation, the transmission distance and the dam length required, as determined by analysis of topographic maps, preclude hydroelectric generation here from further investigation at this time. Coal Coal may be a local fuel resource for Grayling. Although there are limits on coal resource detinition near Grayling, the potential proximity of a coal resource along with a history of coal mining along the Yukon River in the vicinity makes this an attractive resource. The surficial geology of the region north and west of the Yukon River between the Melozitna and Anvik Rivers was described by Chapman (1963) as rounded hills with large, wide cracks and river valleys. The relief near Grayling ranges from 1,000 to 3,000 feet. There is much folding and faulting in this region making local structures generally complex. Coal outcrops are scarce except along the bluffs of the Yukon River where many outcrops have been described. One such outcrop is said to exist 8 miles north of Grayling on the west bank of the Yukon River. This outcrop is evidence of one of the many coal-bearing formations of x the region. Grayling is located in a "known area of coal-bearing rocks." The existance and use of coal in this region has been described since before the turn of the century when Yukon riverboats were propelled by wood or coal-fired steam engines. Although coal was described in 1902 as economically "competitive" with wood as a fuel source for the Yukon steamers, geologists assessing the overall economic potential of the coal resources south of Nulato predicted that coal would not be a viable product for future export but could become a resource capable of meeting all "local" needs. In 1902, one of these geologists, Arthur Collier, accurately predicted that if the crude oil which was to be brought to the region from California during the following year proved practicable as a fuel source for the steamers, "the development of [the] coal beds [would] no doubt be retarded by it." For many years this was the case, and diesel became the fuel of choice, both for barges and power generation. With today's oil costs rising rapidly, it appears to be time to reas- sess the costs and benefits (both dollar and social) of Alaskan coal for local use. Since detailed knowledge of the local coal resource at Grayling is not available, it is necessary to make inferences regarding the resource from descriptions of surficial geology of the area, old analyses of coal samples from nearby abandoned mines and logs of water wells drilled at Grayling by the Public Health Service. Coal beds along the Lower Yukon generally occur in sandstones and shales with intercalated beds of conglomerate. The deposits are dated from middle Cretaceous to Upper Eocene and belong to both the Nulato and Kenai series. Nearly all of these coals are bituminous (although one sample from a deposit near Iditarod was classified as anthracite). Several abandoned coal mines near Grayling were described by Collier in 1902 and 1903. When the U.S.G.S. returned to further assess their economic potential in 1963 (Chapman, 1963), slumping and overgrowth prevented them from locating some of the mines. : Information specific to a coal resource close to Grayling con- sists of the outcrop 8 miles north of the community and Public Health Service well logs. Thirteen wells were drilled at Gray- ling between 1966 and 1977. Logs from wells numbered 1, 2, 4 and ll note coal encountered at a variety of depths and mixed with several other components. These wells were not drilled for purposes of geological investigation, and any reference to coal -is based purely upon observation of the driller. Other wells drilled at Grayling varied in depth from 15 1/2 feet to 190 feet. Some of these other logs have no comments describing the cuttings and may have encountered coal; other holes drilled did not encounter coal. The inconsistent findings of the well logs may be further indication of the complex geology of this area and of possible discontinuity of the coal deposits. It appears that bituminous coal deposits of reasonably good qual- ity for local use might be expected in the vicinity of Grayling. A program of core drilling and sample analysis, along with a detailed feasibility study, is necessary before capital funding for a mining operation to produce a local fuel source can be justified. Timber The region northwest of the Yukon River is forested predomi- nantly with white spruce, with occasional birch stands and some cottonwood and alder. Grayling is located on this northwest bank of the Yukon. Southeast of the Yukon is a region of tundra lowlands almost entirely lacking in forest. The community of Grayling presently makes use of local timber for construction of log or partial log buildings and uses local timber and driftwood for much of its space heating. The forested area in the vicinity of Grayling is described as "interior forest" and is approximately 50 miles from tree line. This forest is roughly estimated to have a sustained yield of 8.5 ft3/acre/year. A timber resource of this quality can supply Grayling's present cord wood requirement for heating in an area of 5.8 square miles, or a square area 2.4 miles on a side (assuming no addi- tional use of driftwood). Grayling's present electrical requirements of 233,300 KWh/year are estimated to require a minimum 850 cords each year for wood-fired boilers and, thus a harvest of 9,000 acres or a square 3.75 miles on a side. Although the cost of obtaining wood from an area this large is expected to be high, it may be possible to combine wood, coal and municipal solid waste as fuel, for a steam producing system. Wood gasification processes for electrical generation is not yet considered to be an available state-of-the-art alternative for application at Grayling. Solar Solar incidence at all of the study communities is concentrated in the summer months. Although lacking in intensity, the daily solar input from long summer daylight hours is considerable. Until annual storage becomes technically and economically feasi- ble, it is not anticipated that solar energy will be competitive with other energy sources for the production of power. However, housing design can make use of passive solar input. Grayling Alternative Plan A Waste heat capture was selected as the alternative having the lowest first cost which following rationale: can offset oil usage. This plan has the 1. There are three potential users of waste heat within 450 feet of the AVEC generators, namely the pump house, the BIA school and the new state high school. 2. All potential users have radiators and/or heat ex- changers that are compatible with waste heat capture delivery system. 3. The waste heat the BIA school It was assumed school and the BIA school can provide all the heating energy for and the PHS (for water heating only). that all the oil consumption for the BIA PHS could be eliminated as follows: 1309.5 X 10®Btu/yr City services 445.5 x 106Btu/yr Total Offset 1775 x 106Btu/yr 4. The value of the fuel saved can offset the AVEC fuel cost. (For simplicity of the economic analysis, the offset was treated as a reduction of heating oil in the village.) 5. At a future date, the new high school could be added to the system with only the addition of some piping. Grayling Alternative Plan B (Coal-fired Steam Plant) This alternative is based on the potential of coal being devel- oped in the vicinity of Grayling and an assumed cost for coal from such a mine at $2.50 per million Btu. The assumed facility size, for analytical purposes only, is 200 KW and will provide sufficient power to process the fuel and provide station power such as that required for crushers are future village expansion. The assumed facility is based on currently available boiler and turbine generator equipment. This equipment results in low "cycle efficiency" of approximately 5 to 6%. To offset this low efficienty, a district heating system is planned to capture the heat in the turbine exhaust steam by heating a water or glycol circulation loop. The assumed power plant configuration consists of a solid fuel fired boiler capable of burning coal wood or solid waste, a back pressure turbine-generator, a condenser to heat the district heating circulation system, an excess heat condenser and a feed water heater. This facility will provide all the electrical and heating energy of the village. In addition, the ;boiler can use the combusti- ble fraction of solid wastes generated in the village as fuel as well as wood. The decision to burn wood depends on the cost per Million Btu of coal versus wood. Costs and Benefits of the Proposed Alternatives Economic analysis of both waste heat capture and coal-fired steam generation of electricity with a district heating system make both of these options appear to be worthy of more detailed analysis. The coal-fired system requires further evaluation of the coal resource itself before more detailed analysis can proceed. The results of this level of investigation are too preliminary to allow estimates of the cost of electricity and heat in future years, but it appears that either of these options would lead to lower costs than would be experienced by merely continuing the present practice of diesel generation (without waste heat capture). In addition to dollar costs, the proposed coal-fired system may have health, safety and environmental risks associated with it. These risks may be minimized through careful planning but more detailed consideration of these will be required before a decision can be made to proceed. There are likely to be social changes which will accompany the transition to a coal system. It is difficult to predict the extent of such changes. The people of Grayling will necessarily not only be involved in any decision making associated with new energy conversion systems but should take an active role in determining whether to pursue the coal option. Summary of Recommendations for Grayling Preferred Energy Alter- native (in order of earliest feasibility) Recommended Resource Assessments and Feasibility Studies 1. Energy conservation No resource assessment or feasibili- - building insulation ty study indicated; immediate action - building envelope required to bring Energy Audit and/ infiltration or weatherization program to this - improved combustion community. 2. Steam from local coal Initiate coal exploration program (augmented by municipal in the vicinity of Grayling to solid waste and/or wood) assess quality and magnitude of re- to cogenerate power and source; perform preliminary design heat for district and feasibility study based upon new heating information. : 3. Waste heat capture Obtain baseline data on heat availa- (to be pursued if steam power alternative un- feasible) bility for specific generators; per- form preliminary design and detailed feasibility study. PROPERTY OF; Alaska Power Authority 334 W. Sih Ave, Anchorage,