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Non-Electric Applications of Geothermal Energy in Six Alaskan Towns 1977
naa ia a GEO Alaska Energy Authority 024 LIBRARY COPY e.2 IDO/1622—4 UC-—66 NON-ELECTRIC APPLICATIONS OF GEOTHERMAL ENERGY IN SIX ALASKAN TOWNS Final Report, October 1976 — November 1977 John Farquhar Ramon Grijalva Patricia Kirkwood November 1977 Work performed under contract No. EY -77—C—07—1622 PACIFICe SIERRA RESEARCH CORP. 1456 Cloverfield Bivd. Santa Monica, California 90404 Prepared for Energy Research and Development Administration Division of Geothermal Energy 1DO/1622—4 UC—66 NON-ELECTRIC APPLICATIONS OF GEOTHERMAL ENERGY IN SIX ALASKAN TOWNS Final Report, October 1976 — November 1977 John Farquhar Ramon Grijalva Patricia Kirkwood November 1977 Work performed under contract No. EY —77 —C —07—1622 PACIFIC * SIERRA RESEARCH CORP. ==" 1456 Cloverfield Bivd. Santa Monica, California 90404 Prepared for Energy Research and Development Administration Division of Geothermal Energy GEO ozy cw NOTICE This report was prepared to document work sponsored by the United States Government. Neither the United States nor its agent, the United States Energy Research and Develop- ment Administration, nor any Federal employees, nor any of their contractors, subcontractors or their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product or pro- cess disclosed, or represents that its use would not in- fringe privately owned rights. NOTICE Reference to a company or product name does not imply approval or recommendation of the product by Pacific Sierra Research Corp. or the U.S. Energy Research and Development Administra- tion to the exclusion of others that may be suitable. Printed in the United States of America Available from National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, Virginia 22161 Price: Printed Copy $ ; Microfiche $2.25 ACKNOWLEDGMENTS The authors are indebted to the many people from the organizations listed below who contributed their time and energy to this project: United States Public Health Service, Office of Environmental Health State of Alaska Department of Commerce and Economic Development, Division of Energy and Power Development Department of Community and Regional Affairs Department of Natural Resources, Division of Oil and Gas Alaska Power Administration Alaska State Housing Authority Alaskan Villages Electrical Cooperative Native Corporations Aleut Chaluka North Alaskan Native Assoc. Arctic Slope Doyon Sealaska Atkasook Inupiat Sitnasuak Bering Straits Kiana Ukpeagvik Bin Googa King Island Council We wish to thank the officials and citizens of the six communities studied for their aid and cooperation; and the five consultants to this project: Abigail Arnold, Robert Forbes, Clifford Hitchins, William Ogle, and Gordon Reistad. The authors, of course, retain full responsibility for any errors or misstatements in this report. We also wish to thank the following equipment vendors and repre- sentatives for their advice and help: William Fletcher Dover Corporation/Norris Division W. B. Garrison The William Powell Company Joseph W. Hagen J. W. Hagen Company, representing Struthers Wells Corporation Edward H. Ireland Reda Pump Company iii Paul McCracken John Nagel Henry Nash Walt Nisbet John L. Sprosty William C. Weaver Berkeley Pump Company Byron Jackson Pump Division Borg Warner Corporation Leeds and Northrup Perma-Pipe Division of Midwesco, Inc. LMH, Inc., Representing American Heat-Alfa Laval Thermal, Inc. American Instrument Company iv TABLE OF CONTENTS ACKNOWLEDGEMENTS . SUMMARY . "- HEATING . OTHER APPLICATIONS ........... DEMONSTRATION SITES . ALASKA VERSUS "LOWER 48"... 2... I. INTRODUCTION... 2... 2... 2 we ee ee ee ee Il. INSTITUTIONAL, CULTURAL, AND LEGAL STRUCTURES AFFECTING RESOURCE DEVELOPMENT . . ~~... eee ee eee wees FEDERAL GOVERNMENT . STATE GOVERNMENT . LOCAL GOVERNMENT . ROLE OF THE NATIVE CORPORATIONS . ECONOMIC CHARACTER OF THE SIX COMMUNITIES SOCIOCULTURAL CHARACTERISTICS OF THE SIX COMMUNITIES III. BARROW. .........-. INTRODUCTION . THE TOWN OF BARROW. . . . 2 «© 2 2 ee ee wee PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR BARROW . . 1 6 6 1 ww ew we www eo - BARROW RESERVOIR MODEL . SYSTEM DESIGN... . ENERGY-EXTRACTION SUBSYSTEM .. DISTRIBUTION-PIPING SUBSYSTEM . SYSTEM COSTS . SYSTEM BENEFITS ........4.4-. COST~BENEFIT COMPARISON... . 2. - e+ ee eee Tv. BUSLIA . 2. 2. 0. 2 ee oe we ew we ew we ww ww THE VILLAGE OF HUSLIA . SPACE~-HEATING ENERGY USE . HUSLIA RESOURCE MODEL . SYSTEM DESIGN . ENERGY-EXTRACTION SUBSYSTEM . iii PNR NR HR 11 11 13 15 16 18 20 23 23 23 Vv. VI. VII. DISTRIBUTION-PIPING SUBSYSTEM . SYSTEM COSTS AND BENEFITS .............. KIANA..... THE VILLAGE OF KIANA . PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR KIANA KIANA RESOURCE MODEL ......... SYSTEM DESIGN... ... 2.2... 2 eee ewes ENERGY-EXTRACTION SUBSYSTEM. ..... DISTRIBUTION-PIPING SUBSYSTEM ............ BASE-CASE SYSTEM COSTS ............-. BASE-CASE SYSTEM BENEFITS . GEOTHERMAL ENERGY AS GROWTH CATALYST: A SPECULATION . WIKOLSKE | 2 THE VILLAGE OF NIKOLSKI............ NIKOLSKI RESOURCE MODEL . SYSTEM DESIGN. ........... ENERGY-EXTRACTION SUBSYSTEM. .......6-. DISTRIBUTION-PIPING SUBSYSTEM. ........2.4... SYSTEM COSTS AND BENEFITS ........... EXTENDED SYSTEM COST-BENEFIT DISCUSSION. .... NOMS a |[62 [ets] tettte- to] fas fe |e [role | as [es] sl) ie) lon lelle ba hah S| ol THE TOWN OF NOME .....-... PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR NOME NOME RESOURCE MODEL . SYSTEM DESIGN . ENERGY-EXTRACTION SUBSYSTEM . DISTRIBUTION-PIPING SUBSYSTEM . BASE-CASE SYSTEM COSTS... ........2.0208- BASE-CASE SYSTEM BENEFITS . COST-BENEFIT DISCUSSION. .......... WRANGELL . 2. 2. 2 we we eee ee ee ee THE TOWN OF WRANGELL . WRANGELL RESOURCE MODEL . SYSTEM DESIGN... .......26.2.2004.4-. vi 50 53 57 57 58 62 62 - 64 » 65 67 70 70 79 79 + 82 + 85 85 87 89 95 97 97 99 103 104 104 105 - 109 109 115 117 117 121 121 “a ENERGY-EXTRACTION SUBSYSTEM. ...........4.. «122 DISTRIBUTION-PIPING SUBSYSTEM ..........4... «125 PRESENT FUEL USE AND COSTS ...........4.4... 126 BASE-CASE SYSTEM COSTS ..............2... 126 BASE-CASE SYSTEM BENEFITS ............... 126 DISCUSSION OF COSTS AND BENEFITS ........... 130 SELECTED BIBLIOGRAPHY ..........2.2.-0202222888.8.. 132 APPENDIX A: THE GEOLOGIC SETTING AND GEOTHERMAL POTENTIAL OF SIX ALASKAN TOWNS AND VILLAGES ............ Al APPENDIX B: HOT, DRY-ROCK RESOURCE LIFE. ............. Bel APPENDIX C: CONSTRUCTION COSTS ............2..4.2.2.2... Cl APPENDIX D: LOAD-SIZING CALCULATIONS FOR HUSLIA AND KIANA . see e Del APPENDIX E: ALASKA DRILLING COSTS ................. EL vii 1. na nF WwW NY ~ 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. LIST OF FIGURES Location of the six towns ..........4.244.-6 Housing in Barrow, Alaska ...... Monthly heating degree days and heating fuel for Barrow . Preliminary geothermal-energy extraction subsystem for Barrow . Preliminary distribution-piping subsystem for Barrow . Increase in natural-gas price for space heating in Barrow com- pared with the cost of a geothermal system..... Single-story log-wall buildings in Huslia . Monthly heating degree days for Huslia...... Preliminary geothermal-energy extraction subsystem for Huslia . Preliminary distribution-piping subsystem for Huslia .... Monthly heating degree days and heating fuel for Kiana, 1975- 1976 . Village Gf Kiana . 0... 5) 5 ee ew tee ei eee ee The high school in Kiana . Preliminary geothermal-energy extraction subsystem for Kiana . Preliminary distribution-piping subsystem for Kiana . Monthly heating degree days for Nikolski .......... Preliminary geothermal-energy extraction subsystem for ME eS 5 [a | oi 5) 4) | | wl le: lel [ol le |e |e lolol oe! | wll ls Preliminary distribution-piping subsystem for Nikolski .. . Monthly heating degree days and heating fuel for Nome, 1975- T9767. «|e jello] «|| «| Ws “st |e: |e Typical Nome houses (photographed in March 1977) Store building in Nome . Preliminary geothermal-energy extraction subsystem for Nome . Preliminary distribution-piping subsystem for Nome . Increase in oil price for space heating compared with the cost of a geothermal system. ........-+40+4e486 Monthly heating degree days for Wrangell . Preliminary geothermal-energy extraction subsystem for Wrangell. . Preliminary distribution-piping subsystem for Wrangell . Increase in oil price for space heating in Wrangell compared with the cost of a geothermal system . ix 25 28 35 36 44 46 47 51 52 59 61 61 63 66 81 86 88 100 102 102 106 107 112 120 123 124 Table © ON DU FF wWHN HB PRR Nb FO LIST OF TABLES Barrow Base-Case Costs ........24.4-. Barrow Base-Case Financial Summary . Huslia Base-Case Costs ........4..2.4.24.-. Kiana Base-Case Costs... .. 2... 2.2. ee Minimum Monthly Dry-Bulb Temperature . . Costs and Benefits of Additional Uses . Open-Hole Test--Cape Espenberg No.-1l Well . Nikolski Base-Case Costs .........2e- Minimum Dry-Bulb Temperature at Nikolski and Cold Bay . Nome Base-Case Costs . Minimum Dry-Bulb Temperatures at Nome .... . Wrangell Base-Case Costs . xi 41 43 54 68 72 78 83 90 93 110 114 127 SUMMARY This report summarizes the potential for direct (non-electric) utilization of local-gradient geothermal energy in six Alaskan towns. A major objective of this study was to stimulate development and use of the geothermal resource provided by the earth's average thermal gradient, as opposed to the few anomalies that are typically chosen for geothermal development. Hence, six towns for study were selected as being representative of remote Alaskan conditions, rather than for their proximity to known geothermal resources. The moderate~temperature heat available almost everywhere at depths of two to four kilometers into the earth's mantle could satisfy a major portion of the nation's heating requirements--but the cost must be reduced. We conclude that a geothermal demonstration in Nome would probably be successful and would promote this objective. HEATING It was hypothesized that the high fuel costs in most of Alaska (due to transportation) and high heating duty-cycle (due to climate) would show geothermal energy to be economically competitive. Based on space heating alone, it was found that a. In Nome and Wrangell, the geothermal costs are close enough to fossil costs to warrant consideration on economic criteria alone; b. Huslia, Nikolski, and Kiana are too small for economic development of the geothermal resources due to the high well costs--development must rely on social advantages; c. In Barrow, geothermal energy cannot compete economically with a natural-gas well located near the town. The table below compares annual costs of geothermal space heating and present conventional heating. The geothermal estimates are highly con- servative, including the capital, interest, and maintenance costs associated with a totally new space-heating system, whereas the conventional estimates include only fuel costs. The geothermal costs are highly eH Projected 30-Year Average Annual Cost Conventional Barrow $6,147,000 $2,137,000 Huslia 2,779,000 178,000 Kiana 2,350,000 422,000 Nikolski 2,410,000 105,000 Nome 5,313,000 3,194,000 Wrangell 2,674,000 2,579,000 sensitive to our estimated cost of drilling in these areas. Uncertainty in the geology and the drilling costs have a major influence on the validity of cost comparisons determined in this study. Advances in drilling technology would significantly lower the costs. OTHER APPLICATIONS The costs of geothermal heat would be reduced by developing additional applications for hot water. Potential applications for utilization of moderate-temperature geothermal energy in the six towns studied are Mumerous and varied. In villages where subsistence patterns dominate the economy, such services as community bath and wash houses, refrigeration facilities, and individual greenhouses can make major contributions to the quality of life but are difficult to equate with cash benefits in a non-cash economy. Similarly, moderate-temperature geothermal heat can enhance rates of bio- degradation for sewage treatment and soil improvement, particularly crucial applications in the Arctic. Special precautions in programs involving ground or soil heating are required in permafrost regions of Alaska including the study towns of Barrow, Nome, and Kiana. DEMONSTRATION SITES The decision to construct a geothermal system will be based on several criteria. The table below summarizes the ratings of each town for a demonstration site as a function of alternative economic and social criteria. ——— Criterion for Sines D t i eenetyetten Nome Wrangell Kiana Nikolski | Huslia | Barrow | To determine relative costs, geothermal vs. alternate — or eo m-_—_ 9) o>. To create high visibility, low-cost installation . oe ee See Seen seen To enhance regional good poor excellent good poor poor development —_— To foster social poor poor good excellent poor poor stability excellent| excellent fair poor poor poor good fair excellent good fair poor We recommend Nome as a candidate for a demonstration of moderate- temperature applications from a hot, dry-rock reservoir. Nome's status as a regional population center and its relatively large population would make such development highly visible and dramatic, as well as potentially cost-effective. Development of the geothermal resource at Nome can be justified on the bases of cost effectiveness, visibility, and the potential economic development of the region. The establishment of social stability--important to smaller, less developed towns in Alaska-- is not a major problem in Nome and therefore does not represent a main issue in determining the feasibility of geothermal utilization. Develop- ment of significant new geothermal uses or a 50-percent reduction in drilling costs would ensure economic viability of this demonstration. Kiana's central location among other villages in the Kobuk-Selawik region, and its highly favorable social climate, make this village a promising site for a total energy system based on geothermal energy (hot, dry-rock resource) and multiple applications. New industry is badly needed in this part of Alaska and would be readily catalyzed by such development. Nearby geothermal resources make Nikolski a very attractive candi- date for geothermal development. The local-gradient resource is expected to be relatively inexpensive to develop, though not cost-competitive for the present small population of Nikolski. An important cultural benefit that would occur with geothermal development at Nikolski is the stabiliza- tion of the Aleut culture, which is in danger of disappearing entirely in future years. This stabilization would also mean continued occupation and growth of Umnak--the oldest continuous settlement in the Western Hemisphere. In time, geothermal energy might generate a cultural and economic oasis. The cost of geothermal development for space heating in Wrangell appears to be competitive with fuel costs over the next 30 years. Wrangell is thus an outstanding candidate for direct-use geothermal energy develop- ment. Because of its relatively strong economy and large population, the criteria of enhancing development, fostering social stability, and creating a highly visible geothermal-energy-use area are less important at Wrangell than at more remote, undeveloped areas in Alaska. Develop- ment of hydroelectric resources near Wrangell is likely and might prove to be complementary (or possibly competitive) to geothermal energy. ALASKA VERSUS "LOWER 48" Legal and institutional factors are expected to make geothermal development in Alaska easier than in the lower 48 states. Fewer regula- tions and permits currently pertain in Alaska, since much of the land with potential for geothermal development is subject to state and federal regulations but few, if any, local regulations. Most land in the areas studied is owned by the state, federal government, or native corpora- tions. The native corporations are generally eager to cooperate in endeavors that promote development in their regions and may invest in such development when geothermal implementation becomes less speculative. Local politics and interactions between regional and local native corpora- tions will require a judicious approach at such a time. For further geothermal development in Alaska, improved drilling tech- nology and concomitant reduction in the cost of drilling will be of pri- mary importance. Though information from this study may be extrapolated to other Alaskan towns, it is not valid to assign similar weights to the in- dividual costs of local-gradient geothermal implementation in towns of the "lower 48." For example, whereas labor and material costs for Alaska run 1.4 to 3 times the base rate in the rest of the nation, Alaskan deep- drilling costs are around 10 times those in the contiguous United States. Reduction of these drilling costs could make utilization of normal-gradient geothermal resources in Alaska economical in the near future. The rela- tively low cost of drilling in the "lower 48" and the dominance of these costs in the final cost-benefit analyses suggest further consideration of local-gradient geothermal energy in the contiguous United States. I. INTRODUCTION In October 1976, Pacific-Sierra Research Corporation (PSR) was con- tracted to investigate the potential application of geothermal energy in the six Alaskan villages (see Fig. 1). The research focused exclu- sively on "Local-Gradient Geothermal: (LGG) resources and their direct, non-electric application, with dual objectives: ° To specify appropriate uses, costs, and benefits within each village; ° To gain broader insight into the validity of routinely using LGG resources in Alaska. The towns and villages investigated in this study were chosen as exemplary of diverse geography, geology, climate, demography, and energy consumption. Each is representative of numerous Alaskan villages; study results, therefore, may be generally applied throughout the state. Sub- sequent sections discuss each of the towns and outline the specific con- siderations that must be made at each site for the implementation of geothermal energy. Some factors, such as the critical need for space heating and the high cost of construction, are characteristics that are common to all the towns. Other factors, such as the existence of permafrost at Barrow, Kiana, and Nome have prompted us to consider these sites differently from Huslia, Nikolski, and Wrangell, where permafrost is not a problem. We have considered present energy-use substitution, as well as potential energy applications that could be implemented within the con- straints of a geothermal system intended primarily to supply district heating. The energy required for greenhouse heating or other alternate uses is available from one of two sources. First, work required to pro- vide district heating to a towm over the facility lifetime requires some decimal number of geothermal wells. Since the number of real wells in a system must be increased incrementally, a demand for 0.7 wells implies that one well must be drilled, a demand for 2.3 wells implies that 3 wells must be drilled, and so forth. An excess fractional geothermal well has a finite irreversible thermodynamic availability, equivalent to some 100 200 Nikolski scale (miles) ‘Fig. 1--Location of the six towns (open circles) determinable thermal power that can be.utilized for a given period of time, and represents a fixed excess thermal capacity. Second, the thermal power demanded for district heating is cyclic, with peak power required seasonally, usually between December and February. If the geothermal facilities are sized to provide peak power, then excess thermal capacity is available for alternate uses when power demand is not high. We have considered both sources of excess power capacity to de- termine the feasibility of utilizing geothermal energy for alternate uses in the six towns. Based on our assessment of energy use and the geothermal resource that can be expected at each site, we have developed a geothermal-energy utilization preliminary engineering design. Our system models for each site are used to derive costs of capital equipment, quantities of direct material, and quantities of direct labor required for each installation. In addition, the models are useful for estimating such variable costs as operating and maintenance expenses. The annual cost of the geothermal system determines project feasibility, and is presented for each town. Il. INSTITUTIONAL, CULTURAL, AND LEGAL STRUCTURES AFFECTING RESOURCE DEVELOPMENT Every Alaskan community exists within a complex matrix of controls imposed by federal, state, local, and private authorities. Geothermal- resource development requires awareness of, and coordination with, these diverse institutions. In addition, any resource development must be under- taken with full knowledge of the delicate social, cultural, and economic fabric of the six study communities. This section describes the insti- tutional, cultural, and legal considerations only in the most general sense; attempts to undertake geothermal-resource development in any of the subject communities should be preceded by more detailed study of these institutional and cultural concerns. FEDERAL GOVERNMENT The federal role in Alaska differs from that in all other states. In 1971, Alaskan natives were awarded nearly one billion dollars and forty million acres of land by the Alaska Native Land Claims Settlement Act (ANCSA). The methods chosen to distribute the land and money man- dated under ANCSA are largely responsible for the present uncertainty about land ownership and regulations, as well as the existence and role of the "native corporations" (discussed below). ANCSA mandated that title to much Alaskan land would be conveyed to Alaskan natives through the structure of regional and local corpora- tions. (A section of ANCSA also grants the Secretary of the Interior the right to withdraw up to 110 million acres. Congress has a December 1978 deadline to determine which governmental agency will be assigned these lands.) Land ownership in Alaska is currently in a state of flux because the majority of conveyances promised by Congress in ANCSA have not yet been completed. At present, the village sites in question are in interim conveyance; i.e., all the paperwork for each site has been completed, but actual conveyance of the land has not been legally il secured or patented. According to the Bureau of Land Management (BLM) and the Alaska State Trustees office, the village parcels of interest to this study will be conveyed--but at an unknown date. Federal Law Governing Geothermal Development The Federal Geothermal Steam Act of 1970 includes: (i) All products of geothermal processes, embracing indigenous steam, hot water, and hot brines; (ii) steam and other gases, hot water and hot brines resulting from water, gas, or other fluids artificially introduced into geothermal formations; (iii) heat or other associated energy found in geothermal formations; and (iv) any by- product derived from them (Public Law 91-581, 91st Congress, Sec. 368). Byproducts are any mineral or minerals (exclusive of oil, hydro-carbon gas, and helium) which are found in solu- tion or in association with geothermal steam and which have a value of less than 75 per centum of the value of the geo- thermal steam or are not, because of quantity, quality, or technical difficulties in extraction and production, of sufficient value to warrant extraction and production by themselves (Public Law 91-581, Sec. 2 ¢&d). Thus, the moderate-temperature hydrothermal and hot, dry-rock re- sources considered in this study are within the guidelines of the federal act. Under Sec. 4 of the act, if one or all of the six study sites were on federal land, the lease applicant with the highest quali- fications would be awarded the lease. Federal lands exempt from geothermal leasing include those within 1) national recreation areas, 2) fish hatcheries administered by the Secretary of the Interior, 3) wildlife refuges, 4) game ranges, 5) wild- life management areas, 6) waterfowl production areas, or 7) areas acquired or reserved for the preservation of fish or wildlife threatened with extinction (Sec. 1014). These exemptions could lead to difficulties in acquisition of land surrounding some of the six villages. The owner- ship of these lands will not be determined until 1978, when the Alaska federal lands are reclassified by Congress. Another difficulty posed by this law is the exemption of land within fish hatcheries, since an important application of geothermal energy is the improvement of hatchery yields. 12 STATE GOVERNMENT The Office of the Governor of Alaska coordinates numerous depart- ments whose activities directly affect local welfare in rural areas. Most apparent are the Department of Community and Regional Affairs, the Department of Health and Social Services, and the Department of Educa- tion. Other state departments are involved in local affairs, pro- portionate to the area's economic activity. The Department of Community and Regional Affairs is generally cognizant of such activities as geothermal utilization. Established in 1972 to provide assistance to community and regional governments, the Department comprises six divisions: 1. The Division of Local Government Assistance provides technical assistance to local governments: training of local officials, tax studies, administration of state revenue sharing and state property-tax exemp- tion programs, collection and publication of local data. 2. The Division of Community Planning furnishes (on request) technical planning assistance to communities, administers grants-in-aid programs, and acts as liaison between communities and state and federal governments. This division also aids in policy preparation and provides planning studies on specific topics. 3. The Division of Rural Development Assistance administers Operation Mainstream and Neighborhood Youth Corps, both of which provide job experience and training for rural residents, and Rural Development Grant programs. Rural Development Grants allocate funds to small rural com- munities for such purposes as health clinics, fire halls, and electrification projects. 4. The Division of State Opportunity provides technical assistance for low-income individuals in technical and legal matters, especially in the fields of educa- tion, housing, health care, public safety, and community improvement. 13 The Local Boundary Commission oversees all local boundary issues, including municipal incorporation, dissolution, annexation, detachment, merger, and consolidation. The Rural Affairs Commission is involved in the improvement of living conditions in rural com- munities and is assisted by the Division of Rural Development Assistance. State Laws Affecting Geothermal Development In 1971, Alaska adopted a Geothermal Resources Leasing Act govern- ing leasing of geothermal resources on state-owned lands (Alaska Statute §38.05.181, 1971). The Commissioner of the Department of Natural Re- sources can issue prospecting permits and leases; he is further em- powered to regulate operations conducted under these leases, including the following: the prevention of waste; development and conservation of geothermal and other natural resources; the protection of the public interest; assignment, segregation, extension of terms, relinquishment of leases, development contracts, utilization, pooling, and drilling agreements; compensatory royalty agreements, suspension of operations or production, and suspension or reduction of rentals or royalties; the filing of surety bonds to ensure compliance with the terms of the lease and to protect surface use and resources; use of the surface by a lessee or permittee of the lands embraced in his lease or permit; the maintenance by the lessee of an active development program; protection of water quality and other environmental qualities. 14 For the purposes of conserving the natural resources of any geo- thermal-resources area, or any part of them, the lessees are granted the right to unite with each other or with others, collectively opera- ting under a cooperative or unit plan of development or operation of the geothermal-resources lands. In addition, any person engaged in the production of geothermal resources under a lease issued by the Department of Natural Resources can commingle geothermal resources from any two or more wells without regard to whether the wells are located on lands for which the lease was issued or elsewhere. A stipulation to this provision is that the lessee has to install and maintain devices that will measure the amount of geothermal resources produced from lands for which the leases were issued. Certain state restrictions must be considered when determining the location of any wells in the six study sites. For example, a well drilled for the discovery and production of geothermal resources is regarded as a public nuisance if it is located 1) within 300 ft of an outer boundary of the parcel of land on which it is situated or 2) within 300 ft of a public road, street, or highway dedicated before commence- ment of its drilling. LOCAL GOVERNMENT Alaska's Constitution emphasizes local (rather than state) govern- ment, encouraging and aiding rural communities in design and implementa- tion of the type of local government best suited to their individual needs. Growth and urbanization are aided by the Department of Community and Regional Affairs through planning and initiating of new services and facilities. The state of Alaska recognizes the city and the borough as the only local government forms that may be given power of taxation. In addition, city and borough governments funnel state services to the local level. The entire state is divided into boroughs, formally designated as "organized" or "unorganized." The organized borough is legally a municipal corporation. The unorganized borough is not a corporation, and was conceived as a means of decentralizing state services and 15 encouraging the local government to develop fiscal and administrative ability to support regional functions. Factors determining a region's progression towards organized government include population, geography, resources, and transportation. According to the original intent of the state Constitution, each unorganized borough will eventually become organized. The only community considered in this study that now exists in an organized borough is Barrow, seat of the North Slope Borough, incorporated in 1972. Title 29 of the Alaska Statutes (Municipal Government, October 1972) allows two classes of " city." Classification, determined by population, specifies the number of members of the governing body or council, selection and responsibility of the mayor, and taxation authority. "First-class cities" (in an unorganized borough) are also school dis- tricts; "second-class cities," although not school districts, have schools operated by the Bureau of Indian Affairs or the State. Of the communities considered in this study, three are first-class cities (Nome, Barrow, and Wrangell), two are second-class cities (Huslia and Kiana), and one is designated a village (Nikolski). ROLE OF THE NATIVE CORPORATIONS Formed in response to ANCSA, native corporations are profit-making organizations. Stockholders are the Alaskan natives entitled under the Act; capital is that granted by the federal government under ANCSA. By virtue of this constituency and economic base, the native corporations constitute a powerful institutional force in Alaska. Native corporations exist on both .regional and local levels. The village corporation and the regional corporation jointly administer the claims settlements. Payments are initially made to the regional corpora- tions. They retain some funds, pay individual natives, and transfer the remainder to the village corporation. Within the first five years, at least 10 percent of the regional corporation's settlement must be paid to its stockholders, and at least 45 percent to village corporations in that region. The regional corporations also assist village corpora- tions in planning claims-money use and in land selection. 16 The six study communities are associated with the following corporations: Village City/Communit Regional Corporation Corporation(s) Nome Bering Straits Sitnasuak, King Island Council Barrow Arctic Slope Atkasook, Ukpeagvik, Inupiat Kiana North Alaskan Native Kiana Association (NANA) Huslia Doyon Bin Googa Nikolski Aleut Chaluka Wrangell Sealaska (none) —— eee The regional corporation represents the village corporation in matters of economic, social, and cultural needs. In practice, however, many schisms have developed between regional and village corporations. These rifts in government have evolved largely because village corporations desire to maintain traditional lifestyles whereas regional corporations emphasize development and investments. The degree of regional-village cooperation bears directly on geothermal-resource development: Section 12 of ANCSA grants surface rights to village holdings to the village corporation and subsurface rights of village holdings to the regional corporation. One stipulation states that the regional corporation may not develop subsurface property underlying village lands without official sanction of the village corporation. Development must involve both the surface and subsurface resources, and thus both village and regional corporations. Other issues pertain- ing to acquisition of land for geothermal development include 1) the regional corporation's interest in development of the resource for a specific village and/or industrial application (greenhouses, mining enterprises, fish hatcheries, etc.); and 2) handling of royalties and 17 Payments to the corporations where the village holds surface rights and the regional corporation holds subsurface rights. Though it must be understood that regional and village interests may differ, these differences should not prevent geothermal-resource development. Disagreements reflect divergent priorities assigned to common values. Resource development that is economically beneficial and socially nondisruptive should easily achieve broad approval. ECONOMIC CHARACTER OF THE SIX COMMUNITIES In Alaska, particularly, conventional cost-benefit analysis tech- niques must be applied carefully when evaluating geothermal applications. Innovative technology is the typical domain of such analysis, usually applied to assess the relative impact on the host system (here, the six communities) of each of several hypothetical alternatives. However, the economic and sociocultural characteristics of several of the studied communities rule out straightforward calculation of costs, benefits, and risks. Five of the six communities are economically unlike towns in the contiguous United States. Wrangell alone boasts a "modern" economy; the other five towns exhibit varying mixes of subsistence and cash- economic bases. Dalton (1965) classifies economies according to the dominance of market exchange; the six communities appear to fit his scheme as follows: TYPE II (subsistence-cash mix; peripheral markets only) TYPE III (cash, market- dominated) TYPE I (subsistence, marketless) Kiana Barrow Wrangell Nikolski : a Huslia +Nome> a 3Nome exhibits a wide economic range because it incorporates a subsistence-based native economy into a cash-based native/non-native economy. 18 Traditional methods for performing cost-benefit analysis assume the existence of a purely cash-based, market-dominated economy. The more "primitive" economies (Nikolski, Huslia, Kiana) lack formal labor mar- kets, capital markets, and distribution systems. Thus, typical econ- omic indicators (e.g., employment) will gauge neither the quality nor extent of economic impact. We cannot presume that any of the six communities will respond in a typical way to technologically created economic change. Providing cheap space heating through geothermal resources may free considerable cash, now spent on fuel oil, for other uses. It is difficult to pre- dict the impact of a cash surplus on a given local economy. Two likely possibilities are equally confounding to classic economic analysis. First, the cash surplus may not materialize; people may no longer attempt to acquire the cash, since it is no longer crucial to sustaining life. Our observations and discussions suggest that many rural Alaskans will maximize leisure rather than money. This choice is in part due to individual preference and in part to traditional community pressure for maintaining economic equality. Second, surplus cash may be distributed in ways that confound classic analytical methods. As Nash (1964) has reported in summarizing primitive economies: "Most peasant and primitive societies have a way of scrambling wealth to inhibit reinvestment in technical advance, and this prevents crystallization of class lines on an economic base" (p. 175). In this light, consider that the "potlatch"* was widely practiced through- out Alaska until fifty years ago :(McFeat, 1966). Although the phenomenon is no longer institutionalized, our experience suggests that the senti- ment and value system that underlay it lives on. Personal observation bears this out, as does recent literature on present-day Alaskan natives (Graburn and Strong, 1973; Jones, 1976). Moreover, discussions with community leaders revealed that available jobs are assigned according to need rather than capability, as a means to equalize wealth. *The potlatch was a community or intercommunity gathering, ostensibly held to celebrate or mourn, where individuals or communities established social rank in direct proportion to one's ability and willingness to give away or destroy possessions. Charity and goodwill had nothing to do with it; Tlingit Indians spoke of it as war, and regarded it every bit as seriously. 19 SOCIOCULTURAL CHARACTERISTICS OF THE SIX COMMUNITIES Plans for and eventual construction of geothermal-based systems in Alaska must reflect the nature and values of four distinct cultural groups: Eskimo, Athapascan Indian, Aleut, and non-native Alaskan. Each culture--and its embodiment within a particular settlement--exhibits a unique and diversified value system, world-view, and resilience (as shown by historical response to cultural and technological perturbation). The Eskimo The Eskimo is the predominant native group within the six subject communities, comprising about 90 percent of Barrow's population, 60 per- cent of Nome's, and 96 percent of Kiana's. Generally characterized in the literature as pragmatic, industrious, and competitive, the rural Eskimos have maintained a degree of cultural integrity despite several decades of economic and technological change. Alaskan Eskimos appear remarkably successful in selecting and adapting (or adapting to) the products and aspects of Western culture that further their aims. The successful transition of the Eskimo culture is partly due to the coincidental near-identity of certain Western and Eskimo values (e.g., pragmatism and materialism). The major source of harmony, how- ever, lies in the intrinsic adaptability of Eskimos, a quality essential to continued survival in the Arctic environment. This adaptability-—- which permeates the culture and its extensions--is manifested as self- reliance, cooperation, and a fatalistic acceptance of nature and her caprice. There is no Eskimo linguistic construct to indicate inevita- bility, i.e., "when I go"; instead, all clauses are conditional, i.e., "if I go" (Chance, 1966). This awareness of and respect for nature is deeply ingrained (Oswalt, 1967; Graburn and Strong, 1973) and should be considered in the evaluation and design of any technological innova- tion whose central purpose is the control of natural forces. The capability for adaptation characteristic of the Eskimo has been extensively studied, in part to construct guidelines for effective and harmonious introduction of new technology. Of special note are five factors identified as essential qualities of nondisruptive tech- nological implementation (Chance, 1966): 20 1. Change must not disrupt or diminish the intense inter- actions and communications among Eskimo communities in transition; 2. Change must not disturb the intricate kinship system; as If expectations are created by the technological trans- fer, the people must have (or be provided with) means to fulfill them; 4. Change must not limit the effectiveness of the traditional Eskimo leadership; 5. The Eskimo community must retain autonomy and independence. The Indian The people of Huslia are generally Athapascan Indian in descent. Despite considerable adaptation, Huslia's society and value system remain essentially Athapascan, stressing unity, equal distribution of wealth, and community independence to the point of isolation. These cultural traits are discussed in the anthropological literature, widely stated by other Alaskans (native and non-native alike), and borne out by our observations. The villagers are very sophisticated, protective of their community, and keenly aware that technology and technologists can be disruptive. Huslia appears in an extended period of a "nativistic movement," its people reaffirming and buttressing traditional cultural values. VanStone (1974) provides an observation on Athapascan culture that is relevant to this study and the methods to be applied. He speaks at length of the Athapascan as intimately concerned (although perhaps below the level of consciousness) with man's place in a harmonious natural environment. To people concerned with their role in a harmonious universe, it is expected that man should be controlled by his world and should attempt to control it in more or less equal parts. The Aleut Aleut culture and its extensions are difficult to discern. The Aleut have a long and violent history of contact with other cultures. 21 They have invariably emerged the worse: five centuries of conflict and exploitation (at the hands of Tlingit Indians, Russians, Americans, and Japanese) have reduced the total Aleut population from approximately 25,000 to 1,700. Originally, Aleut culture mirrored other subsistence societies confronting a harsh natural environment, stressing mutual aid, community harmony, and minimizing (at least the appearance of) individual economic and social advantage. Earlier studies of Aleut communities describe a progressive breakdown of cultural values and ethnic identifica- tion (Berreman, 1954; 1964). Cultural disintegration (exemplified by the expressed desires of every Nikolski child over age nine to emigrate as soon as possible) is attributed to the introduction of compulsory English education, the monetization of the economy, and other changes imposed by remote bureaucracies. A more recent study (Jones, 1976) finds that some Aleut communities have reconstituted. These villages have done so through almost total embrace of Western culture, as opposed to the successful selective adaptations of the Eskimos and Athapascan. Such cultural revival is possible only in the larger villages, which offer the native means for realizing the increased material expectations that invariably accompany "Westernization." III. BARROW INTRODUCTION This section describes the town of Barrow--climate, demography, energy consumption, etc.--then develops in turn 1) a model of the geo- thermal potential underlying the town, 2) a candidate design for a sys- tem fulfilling Barrow's space-heating needs, and 3) the costs and bene- fits expected to accrue to the proposed system. Sections IV through VIII treat each of the other candidate villages in a similar manner. THE TOWN OF BARROW The physical characteristics of Barrow, as well as the way of life of its residents, are very much a result of geographic location. Situated at 71°17'30" N and 156°47'15" W, Barrow is in the West Arctic Subregion of Alaska as designated by the Joint State-Federal Land Use Commission of Alaska. The city's population of about 2500 represents more than half of Alaska's total Arctic population (Selkregg, 1975). Barrow overlooks the Chukchi Sea to the west; to the northeast lies the Beaufort Sea. In winter, the land is contiguous with a vast ice shelf extending into the sea, which is then open as far as the Arctic Ice Pack; inland, snow- covered tundra extends as far as the eye can see. In summer months, much of this land is revealed as shallow thaw lakes and marshes. Because Barrow is located far north of the Arctic Circle, three months of winter pass in continual darkness; and a negative heat balance (outgoing radiation exceeding incoming radiation) exists from September through March. Even during the long daylight periods of summer, the low angle of the sun reduces the intensity of solar radiation, so that net radiation is insufficient to thaw the ground below 30 in. The perma- frost, which in the Barrow region reaches depths of 1300 ft, makes winter the optimum time to move vehicles and heavy equipment across the tundra. Such travel in summer months is extremely destructive to the land. Geologically, Barrow is located on the Arctic Coastal] Plain. In this region, Paleozoic rock layers abutting early Mesozoic layers have 23 formed impermeable pockets of oil and gas deposits. Above these layers are Cretaceous sandstone, conglomerate, and shale; and Tertiary sandstone, conglomerate, and siltstone. The latter is, in turn, overlain by Quaternary and recent unconsolidated deposits (till formed by glaciers of the Brooks Range during the Pleistocene era and consequently deposited on the coastal plain). The prevalence of these silty deposits in the soil around Barrow results in poor growing conditions and technical dif- ficulties in building construction. Although no notable metallic ore deposits have been found in this region, oil, gas, coal, and oil-shale deposits are prevalent. A small gas field at Barrow was originally tapped for the local military base thirty years ago and used until 1964 for space heating of government buildings. In 1964, the Bureau of Indian Affairs initiated a "temporary" system of gas lines to provide space heating for private residences but never replaced that system with a permanent one, leaving the city of Barrow with a dangerous, potentially explosive, energy source. Figure 2 shows some typical dwellings and a gas-line overpass. Predictions indi- cate that the currently used gas field will be exhausted in eight to ten years. Virtually all space heating and cooking is provided by natural gas. Electricity for other needs is provided at a cost of 15¢/kWhr by two 750-kW gas generators and by one dual-source (gas-diesel) 450-kW standby generator. The North Slope Borough uses a 2.5-MW generator through an agreement with Barrow Utilities Incorporated (BUI). A central water-treatment plant derives water from the Isatkoak Lagoon. Though some federal facilities have piped water, most of the town has water delivered by truck; and some people still cut out and melt ice for their water supply. Since Barrow has limited sewage-treatment facilities, most of the town uses either chemical toilets or "honey buckets" (which are collected by truck for incineration). The small amount of precipitation, the poor quality of the soil, the relative lack of sunlight, and the low ground temperature limit the variety of plant and animal life near Barrow. Grasses, berries, and wild flowers, and other small plants, when exposed, support caribou in the summer. The berries and shoots of young plants are gathered for 24 SZ Fig. 2--Housing in Barrow, Alaska. Structure over street in background supports above-ground pipe for natural-gas distribution system, human consumption. Whaling is the major subsistence contribution to the local diet. Hunting of caribou and waterfowl, and fishing for salmon, smelt, and cod also supplement the local diet. A local grocery sells staple and luxury food items. As in many Alaskan towns, government is the largest local employer. Other employment is often seasonal and includes construction, services, trade, and transportation. Total estimated employment in 1974 was 641 people with an average family income of $8560 (Dupere & Assoc., July 1974). Barrow has a twelve—bed hospital and clinic, and two doctors and one dentist. The one elementary and one secondary school have enroll- ments of 115 and 41 students, respectively. Barrow is served by daily Wien Airlines flights from Anchorage via Fairbanks. The frequency and availability of commercial air service seem to have great impact on community life, since the local people are likely to travel to Alaska's major population centers and also are in continuous contact with other Alaskans and tourists. Nevertheless, only a relatively small number of people visit Barrow even in the summer months; but locals are endeavoring to increase tourism. To this end, the Arctic Slope Regional Corporation has constructed a modern hotel. The commercial airline regularly carries freight to Barrow, pro- viding a continuous (though expensive) supply of groceries, including fresh produce, and other provisions. Building materials and other large items may be airlifted in during the winter. Cargo ships are able to reach Barrow only during the months of July through October, as the coast is otherwise icebound, accumulation of pack ice usually beginning in mid- September. Since ocean barges are generally the least expensive means of transporting bulk freight, most fuel (other than local natural gas), vehicles, and building materials are brought to Barrow in this manner. PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR BARROW Climate Barrow is in the Arctic Climate Zone and, although located on the Arctic Ocean, does not have typically coastal weather. Temperatures are generally low, with little variation. Summer temperatures generally 26 range from 29°F to 44°F; winter temperatures, from -25°F to -6°F; and yearly extremes, from 78°F to -56°F. Figure 3 shows monthly heating degree days and fuel use. The average wind of 10.6 kn in the ENE direc- tion, and extreme west winds of 55 kn make the wind-chill factor even colder. Barrow has about 20,000 heating degree days per year. The total annual precipitation average of 5 in. (including the rainfall equivalent of 29 in. of snow) makes this region an "Arctic desert." Buildings Although Barrow is only about 200 mi from Prudhoe Bay, the town has had little impact from the Trans-Alaskan Pipeline. Like many smaller Alaskan villages, Barrow is in a period of transition. Changes in eco- nomic and social patterns are obvious in the physical appearance of the village. Gone is the old village, and taking shape is a small town. This change is reflected by the present juxtaposition of older shacks and huts and modern dwellings. Barrow's 500 residences can be divided into three types. The first, comprising approximately 30 percent of the buildings, consists of "improved shacks" that have been partially insulated. The second consists of shacks built of plywood and scrap materials covered with tarpaper and having plastic sheets over the win- dows for additional insulation. This type of structure makes up about 35 percent of the dwellings. The remaining 35 percent of the residences are newer prefabricated buildings of either plywood or corrugated alumi- num. Most houses in Barrow are 20 ft x 25 ft, but the newer ones are larger with approximate dimensions of 26 ft x 32 ft (see Fig. 2, p. 25). There are 83 commercial buildings in Barrow, including one hotel- restaurant complex, the public health office, a hospital, a high school, and borough and native corporation offices. About 15 of these larger buildings house federal agencies. Present Fuel Use and Costs Virtually all space heating and cooling is done with natural gas. This gas is purchased from the federal government at an artificially low price by BUI. The utility company serves approximately 570 buildings. Baseboard heat and radiant-convective heat (stoves) are common, whereas 27 87 3500 ---—= fuel —s—— days 3000 2500 2000 1500 Annual heating fuel (MCF) 1000 500 Jan Feb March April May June July Aug Sept Oct Nov Dec Fig. 3--Monthly heating degree days and heating fuel for Barrow Heating degree days forced-air systems are unusual and found in only about 5 percent of the buildings. Two hundred buildings have gas-fueled water heaters; in the remaining buildings, domestic water is heated on stoves. Total gas con- sumption for the town's heating.needs in 1976 was 250,000 cu ft (MCF) at an average annual cost of about $400,000 tc the town of Barrow and the federal government. (Gas rates in December of 1976 were 32.4¢/MCF to the Barrow user and 61.4¢/MCF to the federal government buildings.) At the beginning of this study, the gas reserves supplying fuel to Barrow were expected to be depleted in eight to ten years. A recent discovery, though not yet well-delimited, is estimated to be sufficient to supply fuel to Barrow for another thirty years. A recent report for the Alaskan Power Administration (R. W. Beck & Assoc., August 1977) states: Remaining reserves in the South Barrow Gas Field plus those in the potential new discovery have been estimated by some at approximately 75 billion cubic feet of natural gas. Based on these estimates a comparison of reserve and demand figures indicate the natural gas reserves for Barrow could exceed the projected demands to the year 2000 by a very substantial margin. This report continues, recommending that natural gas is the lowest-cost energy source (compared with coal, oil, gas, and wind) for Barrow in the next thirty years, with a projected annual cost of $1,090,000 to $1,600,000 for both space heating and electrical-power generation. Although the gas fields here are included in the Naval Petroleum Reserve No. 4, and therefore are under the jurisdiction of the Depart- ment of the Interior (since their transfer from the U. S. Navy, 1 June 1977), gas rates are "guaranteed" to Barrow in the future by the same public law that has previously ensured such rates. Public Law 94-258, Subsection (e) of Section 104 states: (e) Until the reserve is transferred to the jurisdiction of the Secretary of the Interior, the Secretary of the Navy is authorized to develop and continue operation of the South Barrow gas field, or such other fields as may be necessary, to supply gas at reasonable and equitable rates to the na- tive village of Barrow, and other communities and installa- tions at or near Point Barrow, Alaska, and to installations of the Department of Defense and other agencies of the 29 United States located at or near Point Barrow, Alaska. After such transfer, the Secretary of the Interior shall take such actions as may be necessary to continue such service to such village, communities, installations, and agencies at reasonable and equitable rates. As in other Alaskan towns, multiple uses of non-electric geothermal energy would be possible. These uses include sewage treatment, and com- munity swimming pool, fish farming, greenhouses, algae culture and animal husbandry, and ice melting for drinking water. BARROW RESERVOIR MODEL The Barrow area is underlain by sand, gravel, clay, and sandstone to a depth of about 300 ft. Clay shales, sandstones, siltstones, and shales extend to a total depth of approximately 3000 ft. Below these formations lies a pre-Mesozoic basement of dense black argillite (see Appendix A). The upper level of the surficial deposits is interlaced with ice, and general permafrost conditions exist to a depth of approx- imately 700 ft. The Barrow area has been tested for oil and gas, and geologic assessment of the area (from Appendix A) indicates that: Barrow is underlain by the so-called "Barrow High," a structural high which brings the basement up to relatively shallow depths under the Barrow area. In this case, base- ment is the argillite which was penetrated by the deeper Barrow test holes. Argillite was penetrated at approxi- mately 3385 ft in the South Barrow #1 test well, where the bottom hole temperature was 85°F (30°C). This hole was located one mile southwest of Barrow village, and about 1500 ft south of the coastline. Although there were faint shows of oil in sandstone beds between 3045 and 3165 ft, formation tests recovered no oil or gas. Gas has been produced for local uses from several wells in this area. Brine has been associated with gas blows in at least two test wells. The water chemistry indicates that the waters are probably connate brines rather than sea water. The more reliable downhole gradient measurements ob- tained from the test holes indicates that the average geo- thermal gradient is about 26°C/km under the Barrow area. Based on our assessment of detailed geologic data for the Barrow site, we have developed a resource model that describes the specific 30 thermal gradient (26°C/km) expected. In addition, the geologic analysis indicates the nature of the geothermal resource and the physical proper- ties of the sections that would be encountered at depth. The required resource temperature, site-specific temperature gradient, and physical characteristics of the thermal reservoir impose some broad limits on possible geothermal system configurations and suggest a conceptual ap- proach of how the geothermal resource might be exploited. The resultant heat extraction and utilization systems are then based on realistic judg- ments of resource potential and capacity. An accurate resource model provides a reasonable base upon which to judge the feasibility and the cost of geothermal power for Barrow. The important physical characteristic of the rock groups underlying Barrow is the existence of relatively impermeable, monolithic rock that is expected at depths between 9000 ft and 17,000 ft. We have concluded that a hot (121°C), dry-rock heat source can be expected at a depth of 15,300 ft. Since the "Barrow High" brings basement rock to within 3400 ft of the surface, a thick, relatively impermeable layer of argillite can be expected at depths between 3400 ft and 9000 ft. We estimate, therefore, that the expected volume of sea-water encroachment due to migration through surface fracture systems is negligible and certainly insufficient to provide the capacity required for consideration as a heat-transfer medium. Because no known hydrothermal reservoirs exist at Barrow, two methods of using the hot, dry rock were considered--a one-well and a two-well method. Preliminary calculations indicated that the quantity of thermal power available from a single well with a downhole heat exchanger using conventional well-bore dimensions would not be sufficient. The two-hole method of heat extraction considered is based on use of a hydrofracting process to generate a large-diameter, thin "wafer"- shaped crack that would provide a large downhole heat-transfer area. Water would be circulated down one well, through the crack fissure, and up the second well to remove heat from the hot rock. Hydraulically in- duced rock fractures have been generated by oil companies in the past to increase localized permeability in the vicinity of well-bore holes. The techniques for downhole crack propagation are well developed, and 31 the dense, black argillite structures of Barrow could probably be cracked extensively. The use of hydrofracting, however, has not been proved satisfactory for a continuous-use geothermal-power application. Theoretically, good communication could be established between two wells by means of a hy- draulically induced and maintained vertically oriented fissure that inter- sects both bore holes. Cold water injected into one well at the surface would circulate through the thin wafer crack, extracting heat from the rock. The hydrostatic head in the "cold" well would tend to drive hot, less dense water up the second well. A surface heat exchanger could ex- tract thermal power as a function of fluid-flow rate. A circulating water pump could then complete the loop, discharging cooled water into the first well. In a frictionless system, it would be expected that the circulating pump could be removed from the loop at steady-state condi- tions because the density difference in the two wells would make the sys- tem self-driving. Two factors must be considered before feasibility of such a hot, dry-rock system can be ensured. The first factor is the rate of decay of rock temperature at the crack faces as temperature drop is affected by the load requirements. We assume in this study that mean crack dia- meter will not exceed 3500 ft. Based on the required loads, a required lifetime for the geothermal facility at Barrow determines the number of wells required (see Appendix 8). The resource lifetime for the facility is set equal to the amortization period for the purposes of energy-cost comparisons (presented in Secs. III through VIII). The second factor to be considered is the downhole interwell pressure resistance that will be encountered under normal operating flow conditions. Research conducted at LASL indicates that system pressure resistance can in some instances be quite high. The pressure drop is not related to friction losses through the well casing or piping but is due to the extremely thin spacing between the rock faces at the fissure plane. Technical difficulties must be overcome before the design of a thermal-power production facility is finalized. For this study, we assume that a vertical well will be drilled to a depth where the site-specific thermal gradient will provide a satis- factory source. A hydraulically induced vertical crack would be propagated; 32 1" 1 and the hydrofracted "wafer," or possibly "potato-chip" shaped cavity, would be accurately mapped. We expect that techniques for accurate crack mapping will be demonstrated in the very near future. A second well would be slant-drilled in a plane perpendicular to the surface of sym- metry of the crack. We emphasize that accurate knowledge of the hydro- fracted crack orientation and well placement are critical to maintenance of reasonably low-impedance downhole interwell communication. The crack impedance to circulating water flow is estimated to be an inverse function of the cube of the average crack width at operating pressure. Crack width is considered to be on the order of one millimeter for our "“unpropped" (non-overpressured) crack. For system operation flow rates required, we expect that system operating pressure will be quite high at the proposed Barrow facility. We estimate differential crack-pressure to be about 1500 psig; and the range between minimum crack- entrance pressure and crack-propagation pressure, on the order of 200 psig to 500 psig. We anticipate, therefore, that a pump discharge pressure- control system will be used. We base the system performance and equipment requirements on the somewhat optimistic assumption that impedance due to crack fissure will be around 0.8 psi/gpm. We hope that continued research at Los Alamos will demonstrate that this impedance is reasonable. SYSTEM DESIGN Hot unsaturated water can be considered as a candidate for meeting some of the energy needs of Barrow only if its use is economically com- petitive with other means of heating. To determine if geothermal energy is competitive with other sources, we have developed a preliminary sys- tem for extraction and distribution. Since we are concerned with developing an overall model that repre- sents a workable implementation scheme for the town of Barrow, we per- formed our analysis as a preliminary engineering exercise and not a Parametric study of system costs. We began our technical investigation by determining the thermal power required for district heating. Based on the specific geothermal resource considered, we have developed a 33 preliminary resource utilization model, in accordance with good engineering practice, to site-specific design criteria. We subsequently performed sizing calculations and developed preliminary process specifications for the materials and equipment required for a district heating system in Barrow. With the help of many vendors, we have obtained cost quotations and estimates based on our specifications. Our system design criteria are 1) safety to inhabitants and to the permafrost region; 2) high system reliability; 3) low initial cost; and 4) low O&M cost and complexity. The resource utilization model is divided into the energy-extraction subsystem, discussed above (see p- 30), and the distribution-piping sub- system. Figure 4 shows the energy-extraction subsystem; Fig. 5, a preliminary distribution-piping subsystem. ENERGY-EXTRACTION SUBSYSTEM In developing the geothermal energy-extraction subsystem, we consider it critical that system safety considerations be given high priority. Because of the permafrost underlying Barrow, we have assumed that the spudding-in, drilling, and mud- and cement-injection procedures are identical to those used by deep oil-well drillers when drilling in perma- frost. We consider high-pressure casing necessary because of the rela- tively high pressure required for hydrofracting and normal system opera- tion. Valve and pipe ratings and end connections are in accordance with ASME and ANSI specifications for water service at 1500 psig. The system includes a shell-and-tube counterflow heat exchanger. Although other, low-pressure heat exchangers were considered, we determined that a shell- and-tube heat exchanger with a high-pressure rating on the tubes and tubesheets was required for a hot, dry-rock resource application. Fit- tings and pump casings in the extraction system are also rated for high- pressure service. Cost estimates include allowances for system safety valving and instrumentation, alarms, and control logic devices. We have sized equipment so that flow rates generated by operation of the geo- thermal system will result in noise levels well within OSHA-specified limits. 34 15300 ft Pte accumulator makeup makeup water tank eee distribution system 122°F circ water pump wellhead heat exchanger Y district heating distribution drain system headers geo fluid circ pump distribution system 7 circ water pump drain downhole heat exchange Fig. 4--Preliminary geothermal-energy extraction subsystem for Barrow 9e Fig. 5--Preliminary distribution-piping subsystem for Barrow preliminary wellset locations hot ——— cold Scale in feet & DISTRIBUTION-PIPING SUBSYSTEM Figure 5 shows the candidate water-distribution subsystem to be used for district heating. Water temperature in the distribution subsystem is not to exceed 180°F. Primary safety criteria are that system pressure shall be maintained within reasonable limits, normal system operation shall have a negligible effect on the permafrost region, and no single piping failure shall cause significant damage to the permafrost region. To meet the safety criteria, we determined that maximum distribution-system design pressure be 100 psig. Further, the distribution-piping subsystem should be adequately insulated and isolated from the permafrost region. In addition, no major piping failure should go undetected, and shutoff capability should be- placed at intervals throughout the system. Because the climate imposes such a high duty-cycle on any heating system in Barrow, high system reliability is defined as high availability to the users, with provisions that system failures be repaired quickly at any time of the year. We determined that the type of piping to be used in the system must have an extensive history of reliable operation in similar applications. To ensure high reliability, the distribution system is divided into a header system with periodic crossties provided to bypass failures. Virtually all residences are considered to have service connections in parallel so that individual heaters can be operated independently. We anticipate that at least once in the lifetime of the system the entire secondary loop will be inoperative. Therefore, drain valves at low points in the piping system--necessary for freeze protec- tion--are included in the cost estimate. Low initial cost is a difficult objective to attain in Barrow be- cause of the high cost of direct labor, indirect labor, and materials handling (see Appendix C). To meet the criterion of low initial cost, we considered lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety criteria. The candidate selected for this study is a preinsulated, aluminum-jacketed, fiberglass epoxy pipe that has been used extensively in Alaskan and Antarctic services. The bulk of the system is made up of 8-in. and 2-in. 37 pipe sections. Each section is a spool 20-ft long and is insulated with 2 in. of polyurethane foam. The pipe spools can be handled easily by two men and assembled by relatively unskilled labor. We initially considered installation of underground piping. Instal- lation of such a system in permafrost or cyclically freezing soil is a major problem, however, both in terms of man-hours required and of even- tual damage to the utilidor or piping system. Burying a piping system that would distribute water at temperatures up to 180°F almost certainly implies the use of utilidors, utiliducts, and a forced-air utilidor-cooling system to maintain the integrity of the permafrost. Failures in an under- ground piping system would likely go undetected for an extended period. Consequently, because of the relatively high temperature of the water, a high probability exists that extensive local melting of the permafrost would occur. The resulting subsidence phenomenon could cause extensive damage to the district heating system, as well as possible collapse of ground and structural formations in the immediate area. We estimate that the cost of installing a utilidor system would be in the neighborhood of $200 to $250 per linear foot. For the system proposed for Barrow, the buried utilidor system alone would cost in the neighborhood of $8.6 to $10.7 million. The cost of installing the utilidor does not include the costs of individual service connections, estimated for Barrow to be in the neighborhood of $2900 per house. Because of the likelihood of damage from undetected failures, and because of the high cost of installation, we do not recommend an underground piping system for Barrow. We recom- mend, instead, that the piping be placed in surface-mounted utilidors. Most of the structures in Barrow are built with floors raised off the ground, supported by framing. Generally, enough subfloor space exists to accommodate a pipe and utilidor enclosure above-ground. For the pur- poses of cost optimization, the distribution piping is considered to run directly beneath the structures (see Fig. 5). Piping connections made near or under structures would include tee connections with reducers and cap fittings. Individual user connections to the hot and return distribution lines could be easily installed at the above-ground connec- tions. We estimate that the distribution subsystem would be supported by 38 a system of wooden cradles with pipe supports and slide plates. We ex- pect that thrust blocks would be placed and anchored to support points where the piping changes direction. The piping system could cross small streets by means of a simple riser and downcomer separated by a supported, relatively short, straight spool, similar to the present gas-line crossings. For larger streets, the geothermal-heating lines might be laid under the street in a slightly oversized culvert section. SYSTEM COSTS Table 1 develops detailed costs for the 30-yr life of the system required to supply heat to Barrow. (Appendix C discusses the methods used in deriving these costs and the assumptions that underlie their calculation.) The costs shown include all capital investment, summarized as Research and Development Costs (RDC), Production Costs (PC), and Ini- tial Deployment Costs (IDC). The final cost category, Recurring Costs (RC), includes operating and maintenance costs exclusive of taxes, royal- ties, and interest on capital. The base-case cost estimates for the Barrow system are in turn used to calculate: 1) owning costs, expressed as capital investment amortized over the system lifetime at 10-percent simple interest; 2) annual cost, the sum of that year's owning cost, recurring cost, taxes, and royalties. Table 2 displays these calculations and resulting cost estimates for the Barrow LGG system. SYSTEM BENEFITS In accordance with the design philosophy of direct subsitution for existing fuel sources, system benefits are equal to present and projected village expenditures for space heating. Figure 6 displays these expendi- tures under three alternative assumptions about future natural-gas price rises. 39 COST-BENEFIT COMPARISON Major uncertainties make reliable cost-benefit comparison virtually impossible. The present natural-gas system is nearing the end of its life cycle; the distribution system is reported to be "in poor condition and in need of replacement" (Beck and Associates, 1977). Moreover, the gas wells used to supply Barrow are estimated to be exhausted in eight to ten years. The high costs estimated herein, however, make detailed analysis an academic exercise. The average annual cost of the LGG system--$6.1 million--cannot compare with that estimated for a totally new natural- gas system--$1.1 million to $1.6 million. The natural-gas system would meet all of Barrow's energy needs (including the Naval Arctic Research Laboratory), as opposed to the LGG-based system for space heating alone. The disparity between these alternatives rules out LGG as a likely candi- date for implementation in Barrow. 40 Table 1 BARROW BASE-CASE COSTS (in $ thousands) COST CATEGORY TEAR 1 2 3 4 5-30 Total et A 1. RESEARCH AND DEVELOPMENT COST (RDC) 1.1 Survey 10 10 1.2 Site Selection 10 7 5 22 1.3 Permits 5 3 2 10 ae | eee ee ee eS eT CONS Seen Seeenenenee TOTAL RDC 25 10 7 42 rr 2. PRODUCTION COST (PC) 2.1 Drilling and Well Preparation 2.1.1 Material 2.1.2 Labor 12,450 |11,130} 7,079 30,659 2.1.3 Mobilization 92 92 2.1.4 Loss and Repair 125 111 71 307 2.1.5 Rig Relocation 50 106 112 268 2.2 Wellhead 2.2.1 Material 298 316 335 949 2.2.2 Labor 61 65 69 195 2.2.3 Transportation 34 36 38 108 2.3 Utilidor 507 537 568 | 1,612 2.4 Distribution | 2.4.1 Material 311 330 350 | 1 991 2.4.2 Labor 27 29 31 87 2.4.3 Transportation 28 30 32 | 90 tt TOTAL PC 13,983 112,690 8,685 35,358 Le | (continued on next page) 41 Table 1 (continued) SSS COST CATEGORY YEAR roy nN 3 4 5-30 Total a 3. INITIAL DEVELOPMENT COST “acy 3.1 System Start-Up 3.3.1 Training 8 8 9 25 3.3.2 Technical Data 6 6 3.2 Installation--Checkout 3.2.1 Initial Spares 37 4 Stockage Be : ; a 3.3.2 Labor 82 87 90 259 3.3 Demobilization 78 78 TOTAL IDC 133 134 318 585 4. RECURRING COST (RC) 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory Replenishment 4.1.2 Labor 95 203 320j}18,930) 19,548 TOTAL RC 99 211 333; 19,704} 20,347 4 8 13 774 799 OWNERSHIP COST: RDC 25 10 7 42 PC 13,983/12,690! 8,685 35,358 IDC 133 134 318 585 RC 99 211 333 |19,704| 20,347 ee Se eS OS GRAND TOTAL 14,141/13,033] 9,221 333 119,704! 56,322 eee SS 42 Table 2 BARROW BASE-CASE FINANCIAL SUMMARY Total capital investment $ 35,985,000 143,940,000 4,798,000 30-yr ownership cost (at 10%) Average annual ownership cost Annual Cost--Including Capital Cost, Recurring Cost, Tax (2.25% of Gross Receipts), and Royalties (10% of Gross Receipts) Year Cost Year Cost Year Cost 1980 $4798 1990 $5969 2000 $6286 1981 4897 1991 6000 2001 6319 1982 5009 1992 6031 2002 6352 1983 5756 1993 6062 2003 6385 1984 5786 1994 6093 2004 6418 1985 5816 1995 6125 2005 6451 1986 5846 1996 6157 2006 6485 1987 5877 1997 6189 2007 6519 1988 5907 1998 6221 2008 6553 1989 5938 1999 6253 2009 6588 anti nel eepsenlannthinaenenenainenteetiecnnnenantihtininiee Average Annual Total Cost $6,147,000 43 0Y Annual cost (millions) —-———— Geothermal system base year 1980 | 1985 1990 1995 2000 2005 2010 Fig. 6--Increase in natural-gas price for space heating in Barrow compared with the cost of a geothermal system Iv. HUSLIA THE VILLAGE OF HUSLIA Huslia is located on the left bank of the Koyukuk River, about 300 mi northwest of Fairbanks. A village of about 150 Athapascan Indians, Huslia is far removed from urban Alaska. Although a mail plane stops in the village three times a week, communications with the outside are very limited. The people in this region exist largely in a subsistence manner. The Indians hunt moose for meat and leather, and run trap lines for pelts in the winter. Professional guides and sport hunters are strongly dis- couraged from taking game in the territory around Huslia. The Athapascan women sew moccasins and mukluks from home-tanned leather and use fur skins for making outer clothing. Salmon running in the Koyukuk River are a major food source in the summer. As in many other parts of Alaska, berries are abundant in season. Subsistence living is supplemented by such items as snowmobiles and groceries that are barged into the village twice a year. Since Huslia has no exportable produce, many young men must go elsewhere to find temporary seasonal work. Outside work has included the Trans-Alaskan Pipeline, sawmills, and mining operations. Three diesel generators, rated at 160 kW, 75 kW, and 50 kW, supply Huslia with electricity through the Alaskan Village Electric Cooperative, Inc. (AVEC). In 1974 a water-distribution system was installed, serving most of the village, and septic tanks and flush toilets were installed. Space heating is accomplished by burning spruce in individual wood-burning stoves. Snowmobiles and sleds are used to haul dead or fallen trees to the village, a distance of about six miles. Buildings in Huslia are typically single-story and log-walled (see Fig. 7). Figure 8 presents heating degree’ days. Direct representation is a successful form of local government in Huslia. The village, a second-class city, is ruled by a quorum consisting of all council members plus 50 percent of the village. Meetings are held once a month, but additional meetings are called whenever a topic needs to be discussed. The village is very closely tied to Bin Googa, Inc., the local corporation, through many officials common to both. 45 94 Fig. 7--Single-story log-wall buildings in Huslia ys Heatina deqree da 2500 2000 ~ wo So o — > S So 500 Jan Feb Mar Apr May June July Aug Sept = Oct Fig. 8--Monthly heating degree days for Huslia Nov Dec Discussions with local officials indicate that Huslia, although interested in less expensive sources of energy, is generally cautious in accepting technological change and concerned about the impact that such change would have on the village. SPACE-HEATING ENERGY USE We estimate that Huslia consumes 210 cords of firewood per year for space heating. The current wood supply, six miles from the town, is hauled in by sled (pulled by snowmobile). By assigning shadow prices to the wood and the labor required to cut and transport it, we have arrived at a 1976 energy-cost estimate of $67,000 applicable to space heating. HUSLIA RESOURCE MODEL It is reasonable to assume that the geothermal gradient under Huslia is similar to that measured in the Nulato #1 test well, as geologic map- ping indicates that both localities are underlain by the same formational rock units. Data from the Nulato well indicate that the thermal gradient at Huslia is 18.6°C/km. The minimum fluid temperature considered prac- tical for direct-use applications is 150°F (65.5°C). We have therefore chosen a model that assumes the existence of an aquifer at a depth of 11,600 ft (3.52 km). We first considered various aquifer and utilization system models, including heat-pump topping and continuous blowdown configurations. Because the total cost of the geothermal facility at Huslia is dominated by the cost of drilling, we chose a system that minimizes drilling depth and, therefore, resource brine temperature. We attempted to avoid the cost and complexity of a reinjection well. Unfortunately, the fluid would be rejected as warm (120°F) brine, and would certainly mix with the Koyukuk River water. Because of the impact on the river salmon and the town's potable water supply, we determined that brine blowdown should not be considered, and that reinjection of spent brine is required. Be- cause of the extremely low thermal load in Huslia (1.00 MW), we determined that topping is not required. 48 If a typical connate brine exists under hydrostatic pressure at 11,600 ft, bottom-hole pressure would be (11,600) (0.437) (2.4) = 12,166 psig. Wellhead pressure then could reasonably be expected to be 12,166 - (11,600) (0.437) = 7100 psi. Since the Nulato well did not exhibit high final-flow pressure, we have mo reason to believe that the aquifer at Huslia would exhibit the char- acteristics of a geo-pressured resource; therefore, final hydrostatic head should be much less than 7100 psig. We do, however, assume an artesian condition so that a pressure-reducing valve could be placed at the wellhead and the system would be self-driving. Based on the above reservoir model, a heat-extraction subsystem and a distribution subsystem were developed, sized, and estimated. Sys- tem details and cost conclusions are discussed below. SYSTEM DESIGN As in Barrow, we have modeled an overall geothermal-energy utiliza- tion system for Huslia so that realistic cost estimates can be made. The resource utilization model is divided into the energy-extraction subsystem, which is based on the expected resource discussed above, and the distribution-piping subsystem. The design criteria that we feel are important at Huslia are 1) high system reliability, 2) low initial cost, and 3) low O&M cost and complexity. The system is described below, and Appendix D presents de- tailed calculations for the town. Since the geothermal resource expected at Huslia is not a high-pressure resource, the system is inherently safe for the town's inhabitants. In addition, preliminary investigation in- dicates that permafrost protection is not a system constraint, obviating the need for a surface utilidor system. ENERGY-EXTRACTION SUBSYSTEM Figure 9 represents the preliminary geothermal-energy extraction subsystem. Materials and equipment are rated for the intended service. Piping and valves can be standard schedule, unlike the high-pressure equipment required for Barrow. The heat exchanger is a plate-type counter- flow, low-pressure device with inherently high heat-transfer characteris- tics. Added advantages of plate-type heat exchangers are that they are very simple to disassemble and clean, they can be designed for brine service, and they can be maintained by relatively unskilled personnel. Pumps and pressure-control valves have been specified for low-pressure service. As in Barrow, cost estimates include allowance for block valves, instrumentation alarms, and control logic devices. DISTRIBUTION-PIPING SUBSYSTEM Figure 10 shows the candidate water-distribution subsystem to be used for district heating. Because of the relatively low resource tempera- ture at Huslia, temperature in the distribution subsystem will not exceed 150°F. As in the Barrow facility, operating pressure should not exceed 100 psig. The distribution-piping subsystem should be insulated to minimize heat loss between heat exchanger and users. As in Barrow, no major piping failure should go undetected, and shutoff capability should be placed at intervals throughout the system. Because of the critical need for heating, the system must be highly reliable, with provisions for quick repair of system failures at any time of year. We determined that the type of piping to be used in the system must have a history of re- liable operation in similar applications. To ensure high availability, the distribution :subsystem is divided into a header system with periodic crossties provided to bypass failures. Virtually all residences are designed with service connections in parallel so that individual heaters can be operated independently. We anticipate that at least once in the lifetime of the system the entire secondary loop will be inoperative. Therefore, the drain valves at low points in the piping subsystem—-nec- essary for freeze protection--are included in the cost estimate. 50 to temp — controller distribution system circ pump plate type wellhead heat exchanger 148°F 120°F drain geo fluid reinject pump Fig. 9--Preliminary geothermal-energy extraction subsystem for Huslia » district heating header Fig. 10--Preliminary distribution-piping subsystem for Huslia preliminary location injection well preliminary location extraction well As in other remote Alaskan towns, low initial system cost is diffi- cult to attain in Huslia because of the high cost of direct labor, in- direct labor, and materials handling (see Appendix C). To minimize ini- tial cost, we considered lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety cri- teria. The candidate selected for this study is a preinsulated, aluminum- jacketed, fiberglass epoxy pipe (as was suggested for Barrow). The bulk of the piping system is made up of 3-in. pipe sections. Each section is a 20-ft spool insulated with 2 in. of polyurethane foam. The pipe spools can be handled easily by two men and assembled by relatively unskilled labor. Lacking evidence of permafrost at Huslia, we have based our cost estimate on a buried piping system. For aesthetic reasons, and for pro- tection from accidental mechanical damage, we believe that piping should be buried unless permafrost conditions exist. Individual user connec- tions to the hot and return distribution lines could easily be installed by connecting service lines and short risers to each house. In town, the piping spools could run directly beneath the streets. SYSTEM COSTS AND BENEFITS Table 3 details costs for the Huslia LGG system, and the table below summarizes the full life-cycle costs that would need to be repaid over the system lifetime. We will dispense with further cost- benefit analysis because: e The population of Huslia is too small to consider financing such a system; e No opportunities exist for developing an industrial or agri- cultural rationale for system development; e The future fuel supply for Huslia appears secure: wood re- mains plentiful; bulk fuel storage tanks have been constructed, and the Koyukuk River provides summer access to the storage facility; though the use of the bulk tanks is currently un- certain, economic pressures will dictate their use long be- fore an LGG-based system; 53 Table 3 HUSLIA BASE-CASE COSTS (in $ th ousands) COST CATEGORY 1 2 3 4 5-30 Total _ Sw 1. RESEARCH AND DEVELOPMENT COST (RDC) 1.1 Survey 1.2 Site Selection 1.3 Permits -—}. TOTAL RDC 13 13 mens | fp - PRODUCTION COST (PC) 2.1 Drilling and Well Preparation 2.1.1 Material 2.1.2 Labor 2.1.3 Mobilization 2.1.4 Loss and Repair 2.1.5 Rig Relocation 2.2 Wellhead 2.2.1 Material 2.2.2 Labor 2.2.3 Transportation 2.3 Utilidor 2.4 Distribution 2.4.1 Material 2.4.2 Labor 2.4.3 Transportation 15,000 90 150 50 76 24 23 186 174 20 | | 15,000 90 150 50 76 24 23 186 174 20 -———jeS— TOTAL PC 16,698 (continued on next page) 54 16,698 $$ $$ Table 3 (continued) COST CATEGORY YEAR Sn ener 1 2 3 4 5-30 | Total 3. INITIAL DEVELOPMENT COST (pcy 3.1 System Start-Up 3.3.1 Training 8 8 3.3.2 Technical Data 6 6 3.2 Installation--Checkout 3.2.1 Initial Spares 16 16 Stockage 3.3.2 Labor 82 82 3.3 Demobilization 60 60 ft TOTAL IDC 112 60 172 nh 4. RECURRING COST (RC) 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory 2 2 2 106 112 Replenishment 4.1.2 Labor 95 101 107} 6,336 6,639 TOTAL RC 97 103 109 6,442 6,751 OWNERSHIP COST: RDC 13 13 PC 16,698 16,698 IDC 112 60 172 RC 97 103 109} 6,442] 6,751 GRAND TOTAL 16,823 157 103 109} 6,442) 23,634 55 Huslia demonstrates no compelling social or environmental need for substituting geothermal for surface resources. $16,883,000 67,532,000 2,251,000 2,779,000 Total capital investment 30-yr ownership cost (at 10%) Average annual ownership cost Average annual cost 56 V. KIANA THE VILLAGE OF KIANA Kiana is an Inupiat Eskimo village of about 300 people, located on the right bank of the Kobuk River about 60-mi east of Kotzebue. Kiana lies in the Kobuk-Selawik Lowlands of the Kotzebue Sound Subregion be- tween the Baird Mountains to the north and the Waring Mountains to the south. The lowlands are drained by the Kobuk River and its tributaries. Many meandering streams with large sidesloughs and thaw lakes cover the surrounding plains. Large gravel and sand terraces, 100 ft to 200 ft above sea level, are visible from the air. The river floodplains and gentle slopes that constitute most of the Kiana area are made up surficially of unconsolidated alluvial deposits of clay, silt, gravel, and morainal till from the Pleistocene and recent epochs. Older alluvial and marine sediments have been graywacke, slate, and volcanic rock. Vegetation consists predominantly of scrub and boreal forests. Nearby spruce and poplar forests add to the beauty of this river village. The land in the Kobuk-Selawik area is underlain by discontinuous permafrost. The Kobuk River usually freezes up in October and breaks up beginning in May. Summer temperatures range from 42°F to 68°F, and the winter range is -16°F to 1°F. The weather is not so extreme as in the more interior locations, and Kiana is not near enough to the coast to experience much maritime weather. Precipitation totals only 16 in. each year (including the rain equivalent of 60 in. of snow). Power to all homes in Kiana is supplied by the Alaska Village Electric Cooperative using three diesel generators with 35-, 70-, and 100-kW capabilities. Most houses are heated with fuel oil, which is barged in and bought from a local dealer. Water is drawn from wells and stored in a 20,000-gal reservoir. (Some local people, incidentally, talk of a nearby stream that, they say, is "warm" year-round.) Most of Kiana's homes are serviced by a sewer system with an aeration treatment plant. There are also individual septic-tank systems. 57 Kiana seems an ideal model of technology adapted to rural village customs. The residents support themselves in much the same way as have their forebears for generations. Salmon fishing in the Kobuk and nearby fresh-water lakes is a major activity in summer. Nearly every family has a boat--most equipped with outboard motors--for fishing and river travel. Trapping for fox, lynx, marten, wolverine, weasel, and wolf in the winter is made efficient through widespread use of snow- mobiles. The land provides good grazing for the caribou and moose that migrate to the Kiana region in fall and winter. Grizzly and black bears appear in the nearby hills in the fall as they feed prior to hibernation. Many waterfowl inhabit the region. In addition to this wealth of subsistence resources, Kiana has a strong cash economy. The village boasts two large general stores and a small grocery cooperative. The Kiana mining district has substantial deposits of gold, copper, lead, nickel, and zinc. In the early 1900s, nearly 50,000 oz of placer gold were taken from nearby Klery Creek. No lode mining, however, exists--nor any known petroleum deposits--in the immediate region. Although Kiana has no critical need for alternative energy sources, its people are presently quite dependent on the barge lines for their fuel transportation and have expressed dissatisfaction at the escalating costs of fuel freight charges. PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR KIANA Climate Kiana's weather is somewhat harsher than that of Nome. Since there is no climatological recording station at Kiana, data used in this study were obtained from Noorvik, a village about 30 mi from Kiana. Fuel use in Kiana and climatological data from July 1975 through June 1976 were studied. (Complete fuel-use records were available at the elementary school complex and were helpful in determining the monthly fuel-use patterns for the town.) Figure 11 shows fuel use and heating degree days. The design temperature used for Kiana is -35°F. The lowest 58 otal annual heating fuel Ul Fraction of t 2600 0.12}- ———— fuel _—- days 2200 0.10}- a onl oom Viacom ae a 1800 0.08}— 1400 0.06}— 1000 0.04 600 0.02}- 200 0 July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June 1975 : 1976 Fig. 11--Monthly heating degree days and heating fuel for Kiana, 1975-1976 shep saubap Buizeay recorded temperature in Kiana is -54°F, and the yearly average number of heating degree days is 15,471. Buildings Kiana has approximately 87 buildings. Of these, about 25 are public buildings or stores; 60, houses; and the remainder, unoccupied or storage buildings. Kiana, at most recent count, has a population of 314 and averages about 5 people per household. Most buildings in Kiana are frame, but four are made of logs. In addition, several trailers are in use at present. The average house in Kiana is a 20-ft x 32-ft frame building. Most buildings in this village (Fig. 12) are in good condition and are insulated to about the same degree as houses in Nome. Other nonresidential build- ings in town vary in size and are generally slightly larger than the average housing in Nome. The school complexes, one of which is shown in Fig. 13, have a total area of nearly 20,000 sq ft (compared with a total residential building area of about 38,400 sq ft). Thus, it is not surprising that the fuel used to heat Kiana's school is a large proportion of the town's total use of heating fuel. Present Fuel Use and Cost Everyone in Kiana, with one exception, uses No.-l stove oil for space and water heating. Stoves are generally convective/radiative; and in many instances, the oil cook stove is the only source of heating. The fuel oil, costing 51¢/gal at Kotzebue, is barged to Kiana at a cost of 23¢/gal. The consumer at Kiana pays 97.7¢/gal for this fuel at local stores. One householder in Kiana uses wood for heating fuel. She uses 5 cords of wood per year, which is equivalent to 8.15 x 107 Btu/yr. With a stove efficiency of 0.5, the fuel used to heat her house provides 4.07 x 107 Btu/yr. The remainder of the town used 128,730 gal of No.-1 oil in 1975- 1976 at a cost of $125,769 (plus the "cost" of the firewood--negligible here, but considered important in Huslia, where wood is the primary heat- ing fuel). 60 Fig. 12--Village of Kiana Fig. 13--The high school in Kiana 61 KIANA RESOURCE MODEL Kiana is located on the Kobuk River, about 30 mi north of the Arctic Circle. The town is underlain by 200 ft to 300 ft of surficial sediments in a region where the permafrost is believed to extend to depths of 800 ft. The relatively shallow sedimentary layer is underlain by crystalline schists of the Brooks Range metamorphic belt, including phyllites, green- schists, quartz-mica schists, and blueschists. No thermal springs have been verified in the area near Kiana. Since no deep holes have been drilled in the area, and no downhole data are available, we have estimated a thermal gradient of 30°C/km based on knowl- edge of gradients in other metamorphic terrains. As in Barrow, the deep geologic sections underlying Kiana are essentially monolithic meta- morphic rock, with very low porosity/permeability characteristics. Con- sequently, the expected resource is hot, dry rock that would be exploited by use of an induced fluid system (see Fig. 14). The thermal load required for Kiana is lower than the load for Barrow. We have modeled a geothermal resource of 100°C (212°F) at a mean depth of 3333 m (10,937 ft). This temperature provides a satisfactory amount of heat for the town for 30 years. In addition, the temperature and thermal power that can be developed by drilling to this depth obviate the need for multiple wellsets. Because well costs dominate system costs, it is very desirable to minimize the total drilling required in Alaskan geothermal facilities. SYSTEM DESIGN As for Barrow, the resource utilization model for Kiana is divided into an energy-extraction subsystem and a distribution-piping subsystem. To determine if geothermal energy is competitive with other sources of heating in Kiana, we have developed a preliminary system for extraction and distribution. Because of the geological similarity between the heat resources of Barrow and of Kiana, a single-system model will be used for both towns. Again, system design criteria are 1) safety to inhabitants and to the permafrost region, 2) high system reliability, 3) low initial cost, and 4) low operation and maintenance cost and complexity. The €9 Pte Os accumulator makeup makeup water tank water pump ‘distribution system 122°F circ water pump Neceetec i district heating 7 distribution drain system headers geo fluid circ pump distribution system if circ water pump drain 10940 ft downhole heat exchange Vig. 14--Preliminary geothermal-enerpy extraction subsystem for Kiana system is described below; and Appendix D presents detailed sizing cal- culations for Kiana. The calculations presented are typical of the load- sizing calculations performed for both Barrow and Kiana. Note that for the sake of brevity we have included detailed calculations only for Huslia and Kiana. We used the system size and process-state conditions to develop equipment specifications--for which equipment manufacturers pro- vided accurate, though short-term, cost estimates. The system-sizing considerations made in Appendix D are based on the application of geothermal energy to meet existing load requirements. We do not estimate a trend in population growth in the town, as we feel that moderate growth would affect geothermal- and fossil-fuel use equally. We discuss below alternate applications when the district-heating sys- tems are not fully utilized. ENERGY-EXTRACTION SUBSYSTEM Geological assessment of the crystalline schists underlying Kiana indicates virtually no likelihood of encountering a hot aquifer or a zone of hot rock that has any reasonable degree of permeability. We assume that a normal thermal gradient condition (30°C/km) exists at Kiana and that a hot, dry-rock source (100°C) at 10,940 ft can be expected. The two-hole method of heat extraction considered is based on use of a hydrofracting process very similar to the system discussed for Barrow. As in Barrow, high-pressure casing is considered necessary be- cause of the relatively high pressure required for hydrofracting and normal system operation. Wellhead piping connections, valves, heat- exchanger tubes, fittings, and the pump casing are also rated for high- pressure service. Because of the relatively low temperature of the geothermal fluid, piping and valve cost estimates are to be made on the basis of sizing in accordance with applicable ASME and ANSI codes. Estimates allow for system safety instrumentation, alarms, and control logic devices. We have determined that flow rates generated by operation of the geothermal system described here are within OSHA-specified limits. 64 DISTRIBUTION-PIPING SUBSYSTEM Figure 15 shows the candidate water-distribution subsystem to be used for district heating. Kiana is situated in an area of extensive perma- frost. Because the actual extent and depth of permafrost are unknow, in this study the town will be treated as if it were situated in a region of continuous permafrost. Water temperature in the distribution system is not to exceed 180°F. Primary safety criteria are that system pressure shall be maintained within reasonable limits, normal system operation shall have a negligible effect on the permafrost region, and no single piping failure shall cause significant damage to the permafrost region. To meet the safety criteria, we determined that maximum distribution-system design pressure be 100 psig. Further, the distribution-piping subsystem should be adequately in- sulated and isolated from the permafrost region. In addition, no major piping failure should go undetected, and shut-off capability should be placed at intervals throughout the system. Because the climate imposes such a high duty-cycle on any heating system in Kiana, high system reliability is defined as high availability to the users, with provisions for quick repair of system failures at any time of year. We determined that the type of piping to be used in the system must have a history of reliable operation in similar applications. To ensure high reliability, the distribution system is divided into a header system with periodic crossties provided to bypass failures. Virtually all residences are designed with service connections in paral- lel so that individual heaters can be operated independently. We anti- cipate that at least once in the lifetime of the system the entire second- ary loop will be inoperative. Therefore, the drain valves at low points in the piping system--necessary for freeze protection--are included in the cost estimate. Low initial cost is difficult to attain in Kiana because of the high cost of direct labor, indirect labor, and materials handling (see Appendix C). Because conditions are similar to those at Barrow and Huslia, consider- ation was given to lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety criteria. 65 99 Scale in feet hot ——— cold preliminary wellset location Fig. 15--Preliminary distribution-piping subsystem for Kiana The candidate selected is the same preinsulated aluminum-jacketed, fiber- glass epoxy pipe as recommended for both Barrow and Huslia. For Kiana, the bulk of the piping system is made up of 3-in. pipe sections. Initially, we considered installation of underground piping. Be- cause of the permafrost condition at Kiana, however, we do not recommend an underground piping system. Most of the structures in Kiana are built with the floor raised off the ground, supported by framing. Generally, enough subfloor space exists to accommodate a 6-in. or 8-in. outside-diameter pipe. For the purposes of cost optimization, we assume that the district-heating distribution piping runs directly beneath the structures (see Fig. 15). Piping con- nections made near or under the structures would include tee connections with reducers and cap fittings. Individual user connections to hot and return distribution lines could easily be installed at the above-ground connections. We estimate that the distribution system would be supported by a system of wooden cradles with pipe supports and slide plates. We expect that thrust blocks would be placed and anchored to support points where the piping changes direction. : The piping system could cross narrow streets by means of a simple riser and downcomer separated by a supported, relatively short, straight spool. For wider streets, the geothermal heating lines might be laid underground in a slightly oversized culvert section. BASE-CASE SYSTEM COSTS Table 4 displays the base-case costs of the Kiana LGG system. The table below summarizes the full life-cycle costs. Total capital investment $11,185,000 30-yr ownership cost (at 10%) 44,740,000 Average annual ownership cost 1,491,000 Average annual cost 2,350,000 Table 4 KIANA BASE-CASE COSTS (in $ thousands) YEAR COST CATEGORY 1 | 2 3 4 5-30 Total 1. RESEARCH AND DEVELOPMENT COST (RDC) 1.1 Survey 1.2 Site Selection 1.3 Permits a ae oo. t- TOTAL RDC awa saa — PRODUCTION COST (PC) 2 Hs 2.1 Drilling and Well Preparation 2.1.1 Material 2.1.2 Labor 2.1.3 Mobilization 2.1.4 Loss and Repair 2.1.5 Rig Relocation 2.2 Wellhead 2.2.1 Material 2.2.2 Labor 2.2.3 Transportation 2.3 Utilidor 2.4 Distribution 2.4.1 Material 2.4.2 Labor 2.4.3 Transportation TOTAL PC a a a LS a Neen oeeeee AAv E 13 13 10,000 92 100 50 135 41 11 224 160 173 16 4 11,002 (continued on next page) 68 10,000 92 100 50 135 41 11 224 160 173 16 ee OU IU 11,002 Table 4 (continued) COST CATEGORY YEAR 1 2 3 4 5-30 Total —_——_— 3. INITIAL DEVELOPMENT COST (ipc) 3.1 System Start-Up 3.3.1 Training 8 8 3.3.2 Technical Data 5 5 3.2 Installation--Checkout 3.2.1 Initial Spares 18 18 Stockage 3.3.2 Labor Be 7 3.3 Demobilization 57 57 TOTAL IDC 170 170 Tt ot 4. RECURRING COST (RC) 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory Replenishment 2 2 2 126 132 4.1.2 Labor 95 101 107 | 6,336 6,639 Se I CT A TOTAL RC 97 103 109 | 6,462 6,771 <7 —-renentecrndntervententiemino nme meenenanssnieanesennamed rere neni en etenpe enineaeemesfninnninenienntinnmntnnsainisoes OWNERSHIP COST: RDC 13 13 PC 11,002 11,002 IDC 170 170 RC 97 103 109 | 6,462 6,771 GRAND TOTAL 1,185 97 103 109 | 6,462 | 18,056 69 BASE-CASE SYSTEM BENEFITS As stated above, space heating in Kiana consumes approximately 130,000 gal of stove oil. The total retail value of this stove oil--about $161,000 at the current price of $0.98 per gal--is pegged as the revenue stream permissible in a pure substitution case. It is immediately apparent that economics rule out building the envisioned geothermal system in Kiana solely for space heating. Kiana, however, offers an opportunity to examine the net economic and social benefits that might result from using the excess capacity of the geothermal system to support other applications. Kiana has a small population, but it might easily attract a larger work force from the nearby numerous small towns of the Kobuk-Selawik region. In addition, transportation of materials and produce to and from Kiana presents only minor logistic and economic barriers: the airstrip can accommodate C-130 Hercules aircraft, and the Kobuk River permits barging of equipment during the summer. GEOTHERMAL ENERGY AS GROWTH CATALYST: A SPECULATION The excess capacity of the Kiana system might be used to transform its inhabitants’ way of life. The ensuing discussion illustrates the type and nature of services and industry that might be provided. Where possible, we have attempted to size these services, and conclude with rough estimates of the direct and external costs and benefits that might result from an attempt to fully exploit low-temperature geothermal re- sources in a small Arctic village. The ensuing speculations, however, should be considered within the following constraints: e Detailed design of services and exact cost-benefit calcula- tions are well beyond the scope of the present study; e Like the geothermal system itself, most of the services de- scribed are highly capital-intensive, and serve a constituency that possesses neither capital nor the means for its formation. It is doubtful, therefore, that any of the projects could be undertaken without governmental assistance; 70 e The residents of Kiana have stated no desire to "transform" their town or way of life. The excess capacity at Kiana could support two revenue-producing activities--greenhouse agriculture and aquaculture--and provide three valuable services: 1) water heating; 2) community laundry, bathing, and swimming facilities; 3) enhanced waste treatment. Greenhouse Agriculture Fresh vegetables and other produce are very difficult to obtain in many Alaskan towns. In many parts of the state, severe climate and transportation costs make produce unavailable most of the year. Since demand far exceeds supply, many Alaskans take advantage of the. long summer days by using small conventional greenhouses to extend the short growing season. In Kiana, we consider the use of geothermal energy for greenhouse heating to be a very practical way of increasing produce pro- duction in the spring and summer seasons when district-heating require- ments are low. To determine if an adequate supply of energy is available, we have developed some preliminary estimates of produce demand in the town, as well as some greenhouse thermal-power estimates. The lifestyle of Kiana is still very much that of a hunting and gathering culture. Although agriculture and greenhouse culture are some- what foreign to this way of life, cabbage, root crops, and tubers would be attractive food products to the inhabitants; mushrooms would be a good support crop. Greenhouses with geothermally heated soil beds would allow reasonable production of these vegetables in Kiana. Greenhouse Energy Requirements It is very difficult to maintain constant temperature within a green- house because of the structure's inherently rapid temperature response to changes in solar radiation. As conduction, convection, and radiation heat flows change, conventional greenhouses must be alternately heated and cooled. In addition, coordinated ventilation/temperature control systems must be utilized to maintain proper humidity levels. Fortunately, Kiana's climate is cool, and greenhouse cooling systems are not required. The 71 design of the greenhouse heating system must be based on daily minimum temperature, minimum crop-sustaining temperature, and greenhouse size. Ventilation can be controlled by manually operated or automatically modulated dampers. We have based our heating requirements on 1) a minimum monthly dry- bulb measurement of 0°F; 2) a design wind speed of 15 mph; and 3) pro- viding a four-to-eight-month growing season (see Table 5 ). So designed, greenhouse systems could be operated seasonally when relatively little district heating is required. Table 5 MINIMUM MONTHLY DRY-BULB TEMPERATURE™ ali ee ie Mean Daily Min. (°F) Record Low (°F) January -14.7 -54 February -16.3 -49 March - 6.3 -43 April a -30 May 24.4 -3 June 41.9 2.6 July 47.2 33 August 45.1 22 September 36.4 14 October 21.3 -20 November 4.1 -33 December -10.4 -52 __L 71976 data Heat-transfer losses from our theoretical greenhouse are calculated based on the assumption that double-paned glass will be used. We pointed out above that fluctuations in greenhouse temperature during the day respond very quickly to variations in insolation, and that some modulation of air dampers may be required to control greenhouse temperature and humidity. It is obvious that a greenhouse energy balance during daylight hours is a function of conduction, convection, radiation, and infiltration energy-transfer mechanisms. But maximum required heating load will occur at night, when solar radiation is zero and outside am- bient temperature is at a minimum. Radiation loss from within the greenhouse is negligible. This phen- omenon is referred to as the "greenhouse effect." Clear sheet glass will transmit about 90 percent of incident radiation with wavelengths between 0.3 and 3 microns. But virtually all types of glass are opaque to longwave radiation of the type that would be emitted by bodies with temperatures below 250°F within the greenhouse. At night, radiation will occur outside the greenhouse, i.e., the outside surface of glass will radiate to the "black" sky at a fairly constant rate. This radiation will affect the outside-surface temperature, Tos: which in turn will affect the conduction gradient through the greenhouse wall. A. steady heat-loss model can then be described by a control volume drawn around a section of wall (see figure below), where Io * bog TO 5 ~T Da» 4 4 dR oe(T,, ~ T sky) A> = ' - a, 7 UT - ThA hos = outside-surface convective heat-transfer coefficient = 6.0 Btu/hr £t7°R for 15-mph wind, TS 5 = outside-surface temperature, T. = 460°R for Kiana, o = 0.1714 x 107° Btu/hr et 2°R* (Stefan Boltzmann constant), T = 410°R (effective outer-space temperature), € = 0.94 emissivity for glass, U' = overall heat-transfer coefficient, excluding bos? = = ad 4d 1 2x. x, ~ 9-60 ean ; 1 G air hr £t°°R h,* * * i G air T, = 510°R arbitrarily. 73 Outside Air ve = 15 mph Air Space Inside Air Glass panes == === eae T, = 50°F pb vy =0 4, Then, at steady state, = aC. #q, = O.60C510=T) ) = 6OCT = T+ bobs x LO tT = 2.826-x-10°9) 4 = Io * 4p i oe os 0 aay os i Rewriting: -94 6T + 351.5 = 6.6T +1.61x 10 °T ° os os Solving implicitly for Kiana, mm ° = ° Ty 460°R => To 3 460.5°R . Note that TOs is very close to outside-air temperature. Heat loss through the greenhouse surfaces, qy> can then be calculated directly: = ' _- q, =U A(T, TI) os = 0.6A(510 - TS. — Btu 29.7A reas To calculate infiltration losses and demonstrate thermal-power cap- acity, we have chosen an arbitrarily sized greenhouse to be 20 ft x 2) ft, 10-ft high at top of plate, with a 45° pitched roof. Surface area, A, is then 1566 et? and volume, V, is 6000 ft, 74 Infiltration loss, assuming two exchanges per hour due to air leak- age and controlled ventilation, is q; = 2ove (T, -T,) > where for air at 50°F, 0 = 0.078 4%. ft Btu lb F C_ = 0.24 P and, therefore, Btu ay 11232 hr . Total heat loss from our greenhouse is Qa, +4; = 5742.2 BEY = 1,691 x 1077 Mw for Kiana. Kiana is expected to use an average of 0.89 MW over the life of the facility, but this amount represents only 42 percent of the thermal capac- ity of the facility (see Appendix B)--which implies that 1.23 MW of ex- cess capacity exists at Kiana. Since each of our "standard" greenhouses consumes 1.7 x w7* MW, 72 greenhouses could actually be built. We estimate that this capacity to supply produce far exceeds the demand of the town. Water Heating As demonstrated in the resource-life calculations (Appendix B) for Kiana, a two-hole hot, dry-rock system will provide roughly twice the thermal capacity required for district heating. In addition to space heating, service-water heating, warming of water pipes to prevent freezing, and maintaining an emergency water reserve for fire fighting are possible applications. Due to permafrost discontinuity at Kiana, 75 extensive damage from thawing is less likely than at Barrow, should pipes be run in underground utilidors along with water-distribution and sewer pipes; but problems could still occur. The Public Health Service installed the local water-distribution system here in 1974 and found only occasional permafrost at the 5-ft depths used for burying pipe. Because of uncer- tainty regarding the safety of the permafrost, we do not recommend applica- tions that would involve buried lines. Waste Treatment Kiana has two solid-waste-treatment and two sewage-treatment plants. Aeration and chlorination prior to dumping in the Kobuk River constitute the current environmentally acceptable treatment. Should waste degrada- tion become necessary in the future, or should biodegradation be more economical, geothermal heat could be used because the temperatures in this study are well within the useful temperature range. Enhanced solid- waste-treatment facilities could provide Kiana greenhouses with a resource that is scarce in Arctic regions: rich soil. Composted humus is a routine byproduct of such treatment plants and could be used to renew greenhouse soils. Laundry and Bathing A single community "wash house" would be useful in Kiana, where existing facilities are much more limited than in the larger towns. A "bathhouse" might also be acceptable to the local residents, who occasionally travel by snowmobile to hot springs more than 50 mi from Kiana. Temperatures of about 45°C, appropriate for the bathhouse and acceptable for laundry uses, are well within the capacity of the system. Swimming Pool A geothermally heated community swimming pool, possibly located at the high school, would provide recreation and promote swimming instruc- tion (badly needed in rural Alaska). This is a low-temperature (30°C) use of geothermal energy, and heat required to obtain this temperature is readily available in the proposed Kiana system. Similar applications have been successfully implemented in the Soviet Union and in Iceland. 76 Aquaculture Geothermally facilitated aquaculture, based in the salmon streams of the Kobuk or fish culture in a nearby lake, along with drying and refrigeration facilities, could increase local fishing from subsistence to commercial levels. Temperatures required for aquaculture applications are in the range of 20°C and would be obtainable from the geothermal resource described for Kiana. Since Kiana is in a region of discontinuous permafrost, refrigeration may be more economically accomplished using simple local means such as food-storage cellars. Slow drying of fish, meat, and greenhouse products is possible at temperatures available in the proposed system. Costs and Benefits of Additional Services Table 6 specifies a complement of additional services, all served by geothermal energy. The costs identified are as speculative as the services themselves, based on doubling a range of estimates for similar services in the contiguous United States. Where direct economic benefits may be realized, the estimate and underlying rationale are stated. Most of the accrued benefits are unpredictable. Transforming Kiana in the manner discussed could lead to a considerable population shift to Kiana from neighboring villages. Centralization would bring con- siderable economic return to the town, and would ease the region's economic distress. The primary benefits of the additional services result from enhancing the quality of the natives' lives. We cannot assign a monetary value to this improvement. Social and moral arguments--for or against-- are beyond our competence and charter. The most compelling argument probably lies in designating Kiana a demonstration site to address the uncertainties discussed. The absolute costs are relatively small, the benefits highly uncertain and potentially great. A small investment in the Kiana demonstration could yield important insights and information, applicable to all areas of the Arctic. Alaskan natives are currently in transition: their traditional culture and economy no longer support them, yet they are some distance from full integration into the American mainstream. A demonstration might identify that the most effective role of abundant energy is easing the classic-- and costly--difficulties of transition. 77 Table 6 COSTS AND BENEFITS OF ADDITIONAL USES for: Use Estimated Cost Potential Return : oa ——— Greenhouse Agriculture Heating and soil warming 25 greenhouses, 400 et’, $750,000 to $40,000 to $60,000 export produce $1,300,000 annually (export 5 greenhouses, 400 eee local consumption and local sub- sistence combined) Aquaculture Small open-basin fish farm (salmon) Sewage treatment $8,000 to $20,000 N/A $1,000 to $3,000 (heating only) Decomposed organic wastes to greenhouses; enhanced treatment efficiency Community bath house $30,000 to $55,000 External (QOL) Swimming pool $70,000 and up External (QOL) 78 VI. NIKOLSKI THE VILLAGE OF NIKOLSKI Nikolski, a tiny village of about fifty people, sits on Umnak Island in the Fox Islands group about 800 mi southwest of Anchorage on the Aleutian Chain. The village is situated near Nikolski Bay, between Umnak Lake to the south and Mts. Vsevidof (7050 ft) and Recheshnoi (6510 ft) to the north. The steep, squat mountains and rolling hills are virtually treeless. The region about Nikolski has high geothermal potential. Twenty-five hot springs are scattered along the Chain between Cold Bay and Attu Island. Mt. Vsevidof is an active volcano, as is Mt. Tulik (4111 ft), farther north- east on Umnak Island. Near Tulik is Mt. Okmok (3519 ft) with the Okmok Caldera (6.5-mi wide) at its center. The Aleutian Islands were volcan- ically formed and are part of the chain of active volcanoes encircling the Pacific Ocean. In addition to volcanic activity, the Aleutian region has high earthquake potential due to the subduction of the North Pacific Plate under the Continental Plate, as further evidenced by the Aleutian Trench. The islands proper are located on the Continental Shelf, with the Bering abyssal plain to the northwest and the Aleutian Trench to the south. The people of Nikolski endure a harsh maritime climate. Though the temperatures are mild for Alaska (37° to 50°F in summer, 26° to 39°F in winter), the weather is cloudy, foggy, or rainy much of the time. Annual precipitation is 82 in (34 in. of which is rainfall equivalent of snow- fall); prevailing northwesterly winds average 13.8 kn. These adverse conditions account for a reported 35-percent occurrence of obstructed vision. The land around Nikolski has little agricultural value other than for grazing. Vegetation varies from moist tundral heath in the lowlands to grassy and alpine hillsides. Though Umnak was formerly the site of an active military installation, there is little development at Nikolski and little local employment. A sheep ranch, started in 1936, provides only a few summer jobs. (A short-lived fox farm operated in Nikolski 79 during the 1920s.) Local jobs consist of a janitorial position at the school, that of a part-time health aid for the Indian Health Service, and the position of local postmaster. Unlike other Aleut villages, Nikolski has no commercial fishing industry. Local inhabitants participate in a predominantly cash economy, the men leaving each summer to work elsewhere. Jobs in the region include seal processing at St. Paul, warehouse work at Cold Bay, sheep shearing on another part of Umnak or at Unalaska Island, and fish processing at Unalaska village. Life in Nikolski shows much less urban influence than any of the other sites studied: water is drawn from a nearby pond; sanitary facilities consist of both outhouses and flush toilets with septic tanks; electricity, in 50 percent of the houses, comes from privately operated generators. Climate Although Nikolski is the most southerly of the towns investigated in this study, the harshness of the climate due to wind, precipitation, and humidity makes the fuel use for a residence in Nikolski nearly as great as that for a comparable residence in Kiana. Monthly heating degree days in Nikolski are presented in Fig. 16. (No records of monthly fuel use were available in Nikolski, and bulk fuel is delivered to the town semi-annually.) The mean minimum temperature for the coldest month in Nikolski, January, is 26.2°F, and the total annual number of heating degree days is 9865. Buildings Most buildings in Nikolski are single-story frame residences. The average-size house is 24 ft x 20 ft and is divided into three or four rooms. There are about 20 houses, with occupancy varying from 1 to 5 people in a house and an average occupancy of 2.5 people per house. Although there is no permafrost problem in Nikolski, most buildings do have a dead-air space below the floor. The two largest buildings in Nikolski are the school (with approximate dimensions of 80 ft x 30 ft) and the two-story Russian Orthodox Church (30 ft x 20 ft). Newer buildings in Nikolski are relatively well-insulated. (One person who had recently built a house described the materials as follows: walls of 3/4-in. plywood, 3-in. fiberglass insulation, and 3/8-in. plywood; ceiling insulated with 3-in. fiberglass; floors of 3/4-in. plywood; subfloors 3/4-in. Plywood; 1-ft air space below floor; 80 T8 2500 2000 1500 1000 500 Jan Feb Mar Apr May June July Aug Sept Oct Fig. 16--Monthly heating degree days for Nikolski Nov Dec double- and single-glazed windows.) Older houses are poorly insulated and drafty. (Most of the buildings in Nikolski are "older" buildings.) The local sheep ranch has several buildings, one of which is a par- tially heated barn. Present Fuel Use and Cost Nearly all space and water heating in Nikolski is accomplished with oil-fueled (No.-1 heating oil) cook stoves. Fuel use by residents aver- ages two drums (53 gal) per month in the winter and 1-1/2 drums per month in the summer months. Approximately 25,000 gal of No-1 fuel oil are used for space and water heating in Nikolski each year. The cost of this fuel in 1976-1977 was 92.5¢/gal, making the annual cost of fuel in Nikolski $23,125. Thirty-six drums per month, or nearly 23,000 gal/yr are used for heating at the sheep ranch at a cost of approximately $21,000/yr. All fuel must be shipped into Nikolski on the spring and fall trips of the Northstar III ship through the Bureau of Indian Affairs. NIKOLKSI RESOURCE MODEL Nikolski is located on Umnak Island of the Alaskan Chain, on the " the chain of volcanoes that forms the backbone so-called "Ring of Fire, of the Aleutian Islands and the Alaskan Peninsula. Evidence exists of thermal hot springs on the island, with reservoir temperatures of 150°C or more at Geyser Bight and Hot Springs Cove. Despite this evidence of thermal springs and of volcanism on the island, the structure of the area underlying the town does not suggest that excessively high (150°C) tem- peratures would be encountered by drilling. The Nikolski area is under- lain by sedimentary rocks that are cut or intercalated with keratophyres and albitized diabase sills. It is logical to deduce that the actual gradient is quite good, and that the Tertiary sandstones, siltstones, and other Tertiary rocks would yield a very good saltwater-bearing aquifer. Umnak's heat resource could be exploited in two ways. Tapping the known, high-temperature water at, say, Geyser Bight would minimize the risk of encountering an adequate reservoir. The relatively hot water 82 would have to be piped from Geyser Bight to Nikolski, a distance of eight to ten miles. Although we have not performed a detailed analysis of the economics of such a piping/pumping system, utilization of remote resources is tempting. ; The second way of utilizing geothermal energy at Nikolski would be to drill at or near the village site. Although wells have been drilled near Cold Bay and elsewhere on the Alaskan Chain, none has been drilled in the section of rock that underlies Nikolski. Lacking subsurface informa- tion, we have chosen a model that appears to be similar to Nikolski, based on lithology, geothermal gradient, and aquifers. Geologic assessment of the Nikolski area indicates that rock structures are very similar to those underlying the Cape Espenberg area of the Seward Peninsula. The Cape Espenberg No.-1 well has been drilled, tested, and is considered to be the closest available representation of an empirical resource model for Nikolski. Cape Espenberg well No. 1 is 8373-ft deep. The first 1000 ft are fitted with a 103 -in. I.D. casing. The balance of the hole is fitted with 7% -in. I.D. casing. In open-hole testing (2.76-in. tubing inserted to a depth of 7914 ft), it was observed that the water level rose to a static level of 7414 ft in 230 min. Bottom—hole temperature was 161°F. The water in the hole was analyzed to be a light brine (~2000 ppm NaCl). Table 7 shows pressure readings recorded during the test. Table 7 OPEN-HOLE TEST--CAPE ESPENBERG NO.-1 WELL Recording Depth 8124 ft 8036 ft Initial hydrostatic 4336 psig (10,002 ft) 4296 psig (9,910 ft) Initial flow 3160 psig (7,290 ft) 3118 psig (7,193 ft) Final flow 3541 psig (8,168 ft) 3494 psig (8,060 ft) Final shut-in 3552 psig (8,194 ft) 3499 psig (8,072 ft) Final hydrostatic | 4226 psig (9,748 ft) | 4262 psig (9,827 ft) Source: Standard Oil of California. Well-completion report and log for Cape Espenberg Well No. l. 83 Based on the recorded water-level rise during the test, an average flow rate into the well hole from the aquifer can be calculated. We assume that aquifer capacity is sufficient to drive the level in the 7.62-in.- diameter well and the 2.76-in.-diameter string at the same rate: 2 2 _ (10.75 (7.62 Hl 3 Volume of well filled with water = T(=2) (41) + 2(482) (7373) = 2361 ft 2361 ft? ft? Average flow rate = 0 ain 10.26 wo 76.77 gpm. This flow rate is higher than the flow required for district heating at Nikolski. Due to a lack of information on aquifer characteristics, how- ever, a conclusive statement about both long-term bottom-hole pressure and sustained flow rate cannot be made. Note that final flow pressure is the hydrostatic head of the column of brine. (p = 0.437) in the hole, assuming final flow is zero gpm. Final hydrostatic is bottom-hole pressure against the head of drilling mud used. Since final flow pressure at 8124 ft is approximately 8100 ft of head, some doubt exists that the final fluid level of 7414 ft in the hole was actually recorded under no-flow conditions. For this study, we assume that bottom-hole pressure at Nikolski will not drop to less than the more conservative final flow pressure. The assumption is based on the evidence of fairly high porosity in the aquifer rock structure and on the expected recharge rates. Because of the relatively low flow rate (32 gpm) demanded by Nikolski, we anticipate that diffusion to the bore- hole in the aquifer would be rapid. With these assumptions, minimum bottom-hole pressure would equal 7414 ft of hydrostatic head. Since the borehole depth is 8373 ft, worst-case operation of the well would require that the geothermal brine be pumped 959 ft to the surface. Assuming that the brine encountered at Nikolski would have a tempera- ture of 161°F (as at Cape Espenberg No. 1), a wellhead heat exchanger with the following characteristics could be used: 84 "Hot'' Brine Side: Circulating Water Side: = ° = ° Try 161°F Tiy 122°F = e = ° Tour 140°F Tour 151°F ATi = 13.6°F, assuming a counterflow configuration. The circulating water would then be distributed in Nikolski through a piping system. Figure 17 shows the heat-extraction subsystem. We first considered direct use of geothermal brine, pumping the fluid into the distribution-piping subsystem. This scheme was rejected because of the periodic maintenance problems that would be incurred throughout the system as dissolved solids were accumulated. SYSTEM DESIGN The Nikolski model is very similar to the Huslia model in that both towns would exploit a hydrothermal resource in a region of no permafrost. The major difference between the two sites is that the reservoir at Huslia is artesian, whereas the reservoir at Nikolski must be pumped. The resource utilization model is divided into the energy-extraction subsystem (based on the expected resource discussed above, p. 82ff.) and the distribution- piping subsystem. The design criteria that we feel are important at Nikolski are 1) high system reliability, 2) low initial cost, and 3) low O&M and complexity. Since the gecthermal resource expected at Nikolski is not a high-pressure reso -rce, the system is inherently safe to the town's inhabitants. ENERGY-EXTRACTION SUBSYSTEM Figure 17 represents the preliminary geothermal energy-extraction subsystem. Materials and equipment are rated for light brine service. Piping and valves can be standard schedule, unlike the high-pressure equipment required for the hot, dry-rock applications. The heat exchanger is a plate-type counterflow, low-pressure device with inherently high heat-transfer characteristics. Advantages of plate-type heat exchangers are that they are very good for brine or fouling-fluid service, simple 85 98 Fig. downhole distribution system circ pump district heating headers wellhead plate type heat exchanger 151°F 122° F drain reinject pump 959 ft y pump 17--Preliminary geothermal-energy extraction subsystem for Nikolski to disassemble and clean, and can be maintained by relatively unskilled personnel. Pumps and pressure-control valves have been specified for low-pressure service. As in the other towns considered, cost estimates include allowance for block valves, instrumentation alarms, and logic control devices. The Nikolski heat-extraction subsystem requires the use of a downhole pump to develop the head required for heat-exchanger operation. We be- lieve that it is unreasonable to expect a conventional downhole pump to operate in hot-brine service for extended periods. Consequently, our cost estimate is based on the use of two downhole pumps that can be sequentially operated from a control-panel selector switch. Each pump is controlled by a separate flow controller, on/off/auto station, and discharge-pressure control switch. It is intended that the system can be fully operational with one pump out of service for repairs. DISTRIBUTION-PIPING SUBSYSTEM Figure 18 shows the candidate water-distribution subsystem to be used for district heating. Because of the relatively low resource temperature at Nikolski, temperature in the distribution subsystem will not exceed 151°F. As in the Barrow facility, operating pressure should not exceed 100 psig. The distribution-piping subsystem should be insulated to minimize heat loss between heat exchanger and users. As in Huslia, no major piping failure should go undetected, and shutoff capability should be placed at intervals throughout the system. Because the geothermal resource is re- quired both for town heating and economic self-sufficiency, the system must be highly reliable, with provisions for quick repair of system fail- ures at any time of year. We determined that the type of piping to be used in the system must have a history of reliable operation in similar applications. We assume that virtually all residences have service connections in parallel so that individual heaters can be operated in- dependently. As for the other towns considered, we anticipate that at least once in the lifetime of the system the entire secondary loop will be inoperative. Therefore, the drain valves at low points in the piping system--necessary for freeze protection--are included in the cost estimate. 87 co 100 Ntkolski Bay preliminary location extraction well preliminary location injection well Fig. 18--Preliminary distribution-piping subsystem for Nikolski Because of the high cost of direct labor, indirect labor, and mater- ials handling, low initial system cost for Nikolski is difficult to attain (see Appendix C). To minimize initial cost, we considered lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety criteria. The candidate selected for purposes of this study is the same preinsulated, aluminum-jacketed, fiber- glass epoxy pipe suggested for the other towns considered. The bulk of the system is made up of 2-in. pipe sections. Each section is a 20-ft spool insulated with 2 in. of polyurethane foam. The pipe spools can be handled easily by two men and assembled by relatively unskilled labor. Because of the maritime climate on the Alaskan Chain, no permafrost exists at Nikolski; therefore, we have developed our cost estimate on the basis of a buried piping system. For aesthetic reasons, and for pro- tection from accidental mechanical damage, we believe that piping should be buried unless permafrost conditions exist. Individual user connec- tions to the hot and return distribution lines could easily be installed by connecting service lines and short risers to each house. The piping spools could run directly beneath the town streets. SYSTEM COSTS AND BENEFITS Table 8 displays the base-case costs of the Nikolski system, and the table below summarizes the full life-cycle costs. As in both Huslia and Kiana, Nikolski's space-heating revenue is miniscule compared with the geothermal system costs. Including the adjacent sheep ranch, annual Nikolski expenditures for space heating are less than $40,000. As Nikolski might be appropriate for a high-visibility, low-cost demonstra- tion, we have considered implementing additional applications. Total capital investment $14,506,000 30-yr ownership cost (at 10%) 58,024,000 Average annual ownership cost | 1,934,000 | Average annual cost | 2,410,000 89 Table 8 NIKOLSKI BASE-CASE COSTS (in $ thousands) YEAR COST CATEGORY (—————— 1 2 3 4 5-30 Total oI 1. RESEARCH AND DEVELOPMENT COST (RDC) 1.1 Survey 4 4 1.2 Site Selection 4 4 1.3 Permits 5 5 Fd TOTAL RDC anne 13 _ eee eee 2. PRODUCTION COST (PC) 2.1 Drilling and Well Preparation 2.1.1 Material 2.1.2 Labor a fic 2.1.3 Mobilization 90 ! 90 2.1.4 Loss and Repair 14 14 2.1.5 Rig Relocation 50 50 2.2 Wellhead 2.2.1 Material 59 59 2.2.2 Labor 22 22 2.2.3 Transportation 8 8 2.3 Utilidor 8 | 8 2.4 Distribution 2.4.1 Material 35 35 2.4.2 Labor 43 43 2.4.3 Transportation | 6 6 TOTAL PC 14,335 | 14,335 _ OO oS — SSS (continued on next page) 90 Table 8 (continued) COST CATEGORY YEAR | 3. INITIAL DEVELOPMENT Cost | (IDC) | ' 3.1 System Start-Up 3.3.1 Training 8 8 3.3.2 Technical Daca 6 6 3.2 Installation--Checkout 3.2.1 Initial Spares | Stockage °| | § 3.3.2 Labor 82 ! | 82 3.3 Demobilization 57 | ' 57 ! | | i TOTAL IDC | 138 | | 158 4. RECURRING COST (RC) 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory | ) , Replenishment \ 1 . t 40) +3 4.1.2 Labor | 95}; LoL} 107] 6,336 6,639 ' \ | t ! ! { | | | TOTAL RC | | 96, 102; 108} 6,376 6,682 ; OWNERSHIP COST: RDC | 13 | | | | 43 ! i ' PC 114,335! | 114,335 1 ! | IDC 158 | | 138 { | i ' RC | 96! 102} 108} 6,376 5,682 | | ' GRAND TOTAL 14,506, 96! 102 Greenhouses Implementing greenhouse production, even on a small scale, would provide the town of Nikolski with an increased self-sufficiency, both in terms of food production and economic stability. Since Nikolski is a center of Aleut culture, economic stabilization could help ensure the continuation of the culture, which is in danger of disappearing entirely. Although we consider district heating to be the primary use for energy, we consider the use of geothermal energy for greenhouse heating to be a very practical way of increasing produce production in the spring and summer seasons when district heating requirements are low. To deter- mine if an adequate supply of energy is available, we have developed a preliminary estimate of greenhouse thermal power required. Because of rapid response to changes in insolation, the temperature inside a greenhouse is difficult to control. As heat flows vary, conven- tional greenhouses must be heated and cooled. In the town of Nikolski, we have considered the use of a conventional greenhouse fitted with soil and air heaters that utilize water heated from the geothermal resource. Cooling and humidity control can be accomplished by modulation of air dampers because the outside air temperature is low. Based on daily min- imum temperature, minimum crop-sustaining temperature, and greenhouse size, we have determined the amount of geothermal energy required to heat a greenhouse at Nikolski. We can then compare the amount of power required to the amount of power available from our resource to determine if heating the greenhouse is reasonable. We have based our heating requirements on a minimum seasonal dry- bulb measurement (see Table 9) and a design wind speed of 15 mph. We have chosen a minimum outside design temperature of 10°F for Nikolski, to pro- vide a four-to-six-month growing season. The greenhouse system then can be operated seasonally when relatively little district heating is required. Heat-transfer losses from our theoretical greenhouse are calculated according to the assumption that double-paned glass will be used. 92 Table 9 a MINIMUM DRY-BULB TEMPERATURE AT NIKOLSKI AND COLD BAY \ Mean Minimum Average Minimum Lowest Month Temperature Temperature Temperature (°F) (°F) (°F) tT January 26.2 19.9 1 February 26.8 | 17.8 -3 March 27.3 16.3 -4 April 27.9 22.5 4 May 33.8 32.0 26 June 37.3 38.8 32 July 41.5 44.7 39 August 43.1 45.4 39 September 41.5 40.7 31 October 36.2 34.5 - 10 November 31.1 25.2 15 December 28.4 22.9 1 71976 data from National Oceanic and Atmospheric Administration, Environmental Data Service, National Climatic Center, Asheville, North Carolina. We pointed out above that fluctuations in greenhouse temperature during the day respond very quickly to variations in insolation, and that some modulation of air dampers may be required to control greenhouse temperature and humidity. It is obvious that a greenhouse energy balance during daylight hours is a function of conduction, convection, radiation, and infiltration energy-transfer mechanisms. But maximum required heating load will occur at night, when solar radiation is zero, and outside ambient air temperature is at a minimun. The heat transfer out of a greenhouse is due to conduction, convec- tion, radiation, and infiltration. Clear sheet glass will transmit about 90 percent of incident radiation with wavelengths between 0.3 and 3 microns. But virtually all types of glass are opaque to longwave radiation of the type that would be emitted by bodies within the greenhouse with tempera- tures below 250°F. Therefore, radiation loss from within the greenhouse is negligible. This phenomenon is referred to as the "greenhouse effect." Note, however, that at night radiation will occur outside the greenhouse. That is, the outside surface of glass will radiate to the "black" sky at 93 a fairly constant rate. This radiation will affect the outside-surface temperature, To? which in turn will affect the conduction gradient through the greenhouse wall. Heat—flux calculations have been performed in a manner exactly the same as the procedure outlined in the discussion of Kiana, with T, equal to 470°R. Detailed calculations for heat loss at Nikolski have been omitted, but power cost from a 20 ft x 20 ft greenhouse B 2 is estimated to be 47,697 = , or 1.397 x 10°* Mw. Sheep Ranch and Other Animal Husbandry In addition to space and water heating for the village, space heating of the buildings at the sheep ranch is a major application for moderate- temperature geothermal energy. Small, heated shelters were also suggested by the operators of the sheep ranch as having the potential to increase the survival rate of lambs at birth. The island of Umnak is rich in graz- ing land with the potential to support many more sheep than are raised here at present. An anticipated shearing plant would also benefit from this new heat source, and geothermally heated facilities for washing and drying of wool could increase wool production here to significant proportions. A small mill for the production of yarns would require relatively little further development, and knit Products would allow a profitable cottage industry to form in Nikolski (and possibly on nearby islands) much as has occurred in Iceland. Any of the various wool products could easily be exported to the Alaskan and world markets from the Aleutian chain by the present mcdes of transportation: weekly flights to Anchorage or the semi-annual trips of the Northstar III ship. Acuaculture Nikolski appears to be an ideal setting for a salmon hatchery. Numbers of salmon in this area are diminishing each year. There is a natural salmon stream leading to a large fresh-water pond at Nikolski, as well as another salmon stream just outside of town, where a hatchery could be located. 94 Processing In addition to wool processing, mentioned previously, the capability to process and preserve meat and fish would be greatly enhanced by a large refrigeration facility and, if high-temperature geothermal heat is found to be readily available (from sources further north on the is- land), a local cannery. Drying of kelp for local fertilizer and for foreign markets is another important potential use of geothermal energy at Nikolski. The nearby bays are rich in beds of kelp which could readily be harvested. Other Uses Community bath and wash houses and sewage biodegradation facilities would be appropriate additional uses of geothermal energy at Nikolski. Although small in population, Nikolski appears to have a dramatic poten- tial for multiple direct heat applications of moderate-temperature geo- thermal energy. Although little is known of the geology at Nikolski, the island of Umnak has reported geothermal resources (active volcanoes, hot springs, and hot caves). The island is rich in grazing land, has a natural location suited to the development of a salmon hatchery, already has weekly flights linking it with Anchorage and the rest of the world, is centrally located on the Aleutian chain, and is an idyllic spot to live for those who can find employment there without spending months at a time away from home. The local residents and the Chaluka Native Corporation (the local corporation) as well as the Aleut Corporation are eager to develop the geothermal resources here and to promote a local industry. EXTENDED SYSTEM COST-BENEFIT DISCUSSION Arguments for system construction must again be founded on social concern and the need to demonstrate the effect of abundant energy on the transition from a subsistence to cash economy. Nikolski has consistently lost population since such statistics have been recorded. A geothermal- energy demonstration could reasonably be expected to reverse this trend, drawing settlers to Nikolski from remote islands to the east and west. The Aleut people and culture could recrystallize on Umnak, around Nikolski, 95 the oldest continuous settlement in the western hemisphere. Umnak is equi-distant from Tokyo and Los Angeles, and might serve--in grandiose schemes--as a site for joint U.S.-Japan ventures in agriculture or in- dustry requiring cheap and abundant low-temperature energy. One such application is aluminum production, so highly energy-intensive that the costs of transporting bauxite in and ingots out are more than offset by low energy costs. 96 VII. NOME THE TOWN OF NOME Nome is a legendary gold-rush town situated on the gently rising southern coastal plains of the Seward Peninsula facing the Norton Sound. Although at the time of the Great Gold Rush of 1900, the people of Nome numbered nearly 30,000, today's population is a mere 2,500. No longer a predominantly non-native town, more than half of the local people are Eskimos. Some friction is apparent as the two cultures co-exist in a city whose location, determined by an industry now nearly defunct, offers few resources to support the existing population. Nome has a predominantly cash economy. Government is the.major employer, with jobs in the tourist industry on the increase. Although the Alaska Gold Company of UV Industries, Inc. has recently reactivated two of its gold dredges (shut down since 1962) and is hoping to con- tinue operations, few additional jobs have yet to be provided. At this time, it is still too early to predict the eventual impact of this in- dustry on Nome's economy. Offshore gold dredging has also been con- sidered in this area, but has not yet been developed. Other mineral deposits in the area include tungsten, antimony, and fluorite, but dif- ficulties involved in exporting minerals limit small mining operations. Commercial reindeer herding by natives has not succeeded because of lack of management of the herds. A small reindeer-processing plant in Nome is closed at present. Nome lacks a deep-water port. The shallow coastal waters (i.e., only 80-ft deep, 30,000-ft offshore) necessitate lightering of cargo with barges approximately one mile from shore. Freight costs are thus increased by about 25 percent. New barge facilities have been studied and proposed, but the economic feasibility of such a project has yet to be proven. The coast at Nome is currently protected by a rock seawall built by the Army Corps of Engineers in 1951. Prior to that time, coastal storms brought severe damage to the town and heavy beach erosion during the summer months. As recently as 1974, a coastal storm caused major 97 flooding that reached inland as far as the airport. Other detrimental coastal influences include "ice push" (where huge sheets of ice are pushed inland during storms), prevailing shore drift, and deposition af gravel and silt in the already shallow waters. Permafrost up to 600-ft deep underlies most of this region and is an important consideration in building construction. Several buildings in downtown Nome show the effects of “frost heave." Breakup usually occurs in the Norton Sound around May 29, and freezeup around November 12. (This past year, however, has been an unusually warm one in Alaska, and many major bodies of water had not completely frozen by late January.) Nome normally experiences maritime weather from June through November, with cool summers (39° to 56°F) and moderate winters (-3°F to 14°F). Precipitation is annually about 16 in. (including the equivalent of 54 in. of snow). Temperature inversions are common; but the open terrain and moderate winds (averaging northerly at 9 kn) generally alleviate any air pollution. Blowing dust (from unpaved streets), however, is a serious summertime problem. Many people of the Nome area depend on sparse natural resources for a great part of their subsistence. The surrounding terrain is gen- erally moist tundra, low hills, and sand dunes. Plant growth is limited to small shrubs, lichens, mosses, berries, and grasses. The small num- bers of grazing animals such as caribou and moose found in the area are important food sources. The Nome and Snake Rivers have an annual salmon migration, and fish (including tomcod, herring, whitefish, smelt, and steelhead trout) forms a major component of the local diet. No com- mercial fishing is done in the area, though the potential of such an industry has been studied. Walrus and seal are taken near Nome, the skins and ivory fashioned and sculpted by native craftsmen for local sale and export. Nome, like Barrow, is accessible by air, with regular service pro- vided by Wien and Alaska Airlines. People from nearby villages travel to Nome for shopping and health care. A hospital and clinic is staffed by three doctors and three dentists. Children from outlying villages come to Nome for secondary education. 98 Most homes in the town are served by Nome Light and Power Utilities, whose five diesel generators (three rated at 60 kW, one at 350 kW, and one at 1233 kW) provide electricity at a cost of 13¢/kWhr. Heating is done with fuel oil. Surface water is taken from springs and wells and stored in a reservoir before distribution. Many houses are served by water mains and sewer lines, but approximately half of the population still have water delivered to their houses and depend on "honey bucket" pickups. A comprehensive city water and sewer plan was developed in 1976 and will probably be constructed when funding becomes available. PRESENT ENERGY CONSIDERATIONS AND REQUIREMENTS FOR NOME Climate The subarctic climete is a major influence on Nome's heating load. The period July 1975 through June 1976 is taken as a typical weather year for purposes of this study. The same period for 1976-1977, for ex- ample, does not provide representative data for Alaska, since this was an unusually warm year. Figure 19 shows monthly heating degree days (NOAA, 1965-1976) and fuel use for Nome. Fuel use is based on monthly fuel deliveries to representative buildings in Nome. (Total annual fuel is discussed below.) Nome climatological data (NOAA, 1941-1970), including temperature extremes and average wind values, lead us to choose a design temperature of -28°F for this locality. Buildings Although many buildings in Nome are poorly insulated and not "tight," most older buildings that were not originally insulated have been im- proved to varying degrees by their owners, and new buildings are generally well insulated. Windows are double glazed, fitted with storm windows, or covered with flexible plastic during the coldest months. Snow is piled up around the houses in the winter months to provide additional insulation and to make a more effective dead space under the floor. (This practice leads to "frost heaves" in the permafrost, and, as a con- sequence, houses must be levelled every year.) 99 OLT Fraction of total annual heating fuel 0. lo 0.14 0.12 0.10 0.08 0.06 0.04 0.02 July ———-— fuel —- days Aug Sept Oct Nov Dec Jan Feb Mar Apr May 1975 1976 Fig. 19--Monthly heating degree days and heating fuel for Nome, 1975-1976 June 3000 2600 2200 1800 1400 1000 600 200 skep saubap Bulzeay Nome has about 1500 buildings, including garages and sheds. Approx- imately 85 percent of its 600 heated buildings are single-dwelling residen- tial; 5 percent, multiple dwelling (4-12 units); and 10 percent, churches, government buildings, or stores. Single-dwelling houses may be categorized into three main types: approximately 35 percent, single-story "shacks" with average dimensions of 1l ft x 14 ft; 40 percent, single-story 24-ft x 36-ft houses; 25 percent, two-story 24-ft x 34-ft houses. Most buildings are frame; some, quonset huts and trailers; and many, combinations of two or more building types. Figures 20 and 21 picture examples of typical build- ings in Nome. Most heating systems in Nome are oil-fueled. About 35 percent are space heaters with fans and no ducts or hot-air furnaces with ducts; 25 per- cent, circulating hot-water heaters; 30 percent, space heaters or cook stoves that heat by convection and radiation. Domestic water is usually heated by the stove used for space heating, though a few houses have electric hot- water heaters. The average house has five to six residents. Many houses in Nome have a south-facing anteroom with large window areas. These rooms are warmed when the winter sun is above the horizon and provide additional insulation plus some heat to the rest of the house. Present Fuel Use and Cost Nearly all of Nome's present geothermally replaceable energy load comprises space and water heating. All bulk fuel is barged into Nome from Standard Oil's Richmond Beach plant near San Francisco. Package products (e.g., oil, grease, fuel in 5-gal cans) are shipped from Seattle. No local natural fuel resource (other than driftwood, which is used in negligible amounts) exists at this time. (Though in the past local Eskimos used whale oil, all other fuels have been barged to Nome since the curn of the century.) Because of the barge and lighterage costs, fuel prices in Nome are high. Lighterage, necessary due to the lack of deep-port facilities, adds approximately 25 percent to the cost of fuel. Nearly all heating in Nome is fueled by No.-l stove oil and, to a much lesser degree, by No.-2 oil. From July 1975 through June 1976, 2.127 x 10° gal of oil 101 Fig. 20--Typical Nome houses (photographed in March.1977) Fig. 21--Store building in Nome (made up of several smaller units of varying construction types) 102 were used for heating in Nome, with a total cost to users of $1,212,000. Other fuels--which had a negligible impact on this figure--included pro- pane, white gasoline, kerosene, and driftwood. The volume of oil used for heating is equivalent to 2.98 x 19° Sen + The actual volume of oil consumed and the heating value are used to develop the design heating load. Calculations and assumptions for load determination are described in Appendix D. NOME RESOURCE MODEL The Nome area is underlain by metamorphic rocks of the Nome Group, including interlayered greenschists, quartz-mica and garnet-mica schists, and schistose marbles. The bedrock is generally overlain with sedimentary deposits ranging in thickness from 30 ft to 80 ft. Nome is located in a permafrost region; and although the permafrost may be perturbed due to the warming effects of seawater, it is believed that permafrost extends to a depth of approxima*ely 800 ft. No known thermal springs exist in Nome, although Pilgrim and Serpentine Hot Springs are located 40 mi and 100 mi, respectively, north of the town. Since no deep holes have been drilled in the Nome area, we have based our assessment of the geothermal gradient on gradients in known basement rocks elsewhere. We assume that the gradient at Nome is approximately 30°C/km (see Appendix A). We believe that the crystalline schists of the Nome Group have very low fracture porosity/permeability. Because of the permafrost layer, and the limited fracture systems, we believe that the basement rock would not contain water of sufficient capacity to be considered as a usable aquifer. As in Barrow, we believe that the only usable model for Nome is a hot, dry-rock system with induced heat extraction. By Alaskan standards, Nome is a large town, with a population of about 2500. Because of its size and relatively severe climate, the heating requirements for the town are high. As discussed in Appendix E, drilling in Alaska is extremely expensive. To minimize the number of wells required to provide thermal power for Nome, we have modeled our hot, dry-rock resource as a 250°F hydraulically induced fissure system with forced-fluid heat extraction. Detailed discussion of the heat-utilization systems, resource life, and cost considerations are presented below. 103 SYSTEM DESIGN Nome is treated in the same manner as Barrow, with the resource- utilization model being divided into the energy-extraction subsystem and the distribution-piping subsystem. To determine if geothermal energy is competitive with other sources, we have developed a preliminary system for extraction and distribution. The geological similarity be- tween the heat resources of Nome and of Barrow prompted us to treat both towns with the same model. System design criteria are 1) safety to inhabitants and to the permafrost region, 2) high system reliability, 3) low initial cost, and 4) low operation and maintenance cost and complexity. The system is described below. Although Nome is considered a relatively good candidate for geothermal-energy development, we have not included our detailed design-sizing calculations in an appendix. The analysis is, however, similar to the calculations presented for Kiana (Appendix D). We used the system size and process-state conditions to specify equipment, and equipment manufacturers provided accurate cost estimates based on our informal specifications. The system-sizing considerations are based on the application of geothermal energy to meet existing load requirements for district heating. Population growth and additional capacity for alternate uses have not been considered. Historically, Nome's population has been decreasing, although a self-sufficient energy base might prompt growth. As pointed out above for Kiana, population growth will probably affect both fossil-fuel and geothermal energy use equally. Note that sizing estimates for Nome utilize about 87 percent of the resource modeled. Excessive growth would require an additional well set, which would increase system cost by about 45 percent. ENERGY-EXTRACTION SUBSYSTEM Judging from a geological assessment of the Nome rock structure, we conclude that a hot (121°C), dry-rock heat source can be expected at a depth of 13,130 ft. That conclusion assumes that a normal gradient of 30°C/km exists at Nome. We estimate that the expected volume of seawater encroachment due to migration through surface schist fracture 104 systems is negligible and certainly insufficient to provide the capacity required for consideration as a heat-transfer medium. A qualitative discussion of the hot, dry-rock concept is discussed in the system-design section on Barrow (see Fig. 22). We estimate that the spudding-in, drilling, and mud- and cement- injection procedures used by oil-well drillers in a permafrost region apply. High-pressure casing is considered necessary because of the rela- tively high pressure required for hydrofracting and normal system opera- tion. Wellhead piping connections, valves, heat-exchanger tubes, fittings, and the pump casing are also rated for high-pressure service. Because of the relatively low temperature of the geothermal fluid, piping and valve cost estimates are to be made on the basis of sizing in accordance with applicable ANSI and ASME codes. Estimates allow for system safety in- strumentation, alarms, and control logic devices. As for Barrow and Kiana, we have chosen equipment that ensures that flow rates generated by the operation of the geothermal system described here are within OSHA-specified limits. DISTRIBUTION-PIPING SUBSYSTEM Figure 23 shows the candidate water-distribution subsystem to be used for district heating. Nome, like Kiana, is situated in an area of extensive permafrost. Because the actual extent and depth of perma- frost are unknown, Nome will be treated in this study as if it were situated in a region of continuous permafrost. Flow of water through the hot side of the high-pressure heat exchanger is modulated so that water temperature in the distribution subsystem does not exceed 180°F. Primary safety criteria are that 1) system pressure shall be maintained within reasonable limits, 2) normal system operation shall have a negligible effect on the permafrost region, and 3) no single piping failure shall cause significant damage to the permafrost region. To meet the safety criteria, we determined that maximum distribution- subsystem design pressure be 100 psig. As for Barrow and Kiana, the distribution-piping subsystem should be adequately insulated and iso- lated from the permafrost region. In addition, no major piping failure should go undetected, and shutoff capability should be placed at inter- vals throughout the system. 105 a accumulator makeup makeup water tank = water pump distribution system 122°F circ water pump wellhead heat exchanger v district heating distribution drain system headers 90T geo fluid circ pump distribution system bf circ water pump 13200 ft ; drain downhole heat exchange Fig. 22--Preliminary geothermal-energy extraction subsystem for Nome LOT 0 200 400 Scale in feet hot ——— cold re preliminary ie wellset locations LS eS NS Fig. 23--Preliminary ‘distribution-piping subsystem for Nome Because the climate imposes such a high duty-cycle on any heating system in Nome, high system reliability is defined as high availability to the users, with provisions for quick repair of system failures during any season. To ensure high reliability, the distribution system is divided into a header system with periodic crossties provided to bypass failures. We assume that residences have service connections in parallel so that individual heaters can be operated independently. We anticipate that at least once in the lifetime of the system the entire secondary loop will be inoperative. Therefore, drain valves at low points in the piping system--necessary for freeze protection--are included in the cost estimate. To meet the criterion of low initial cost, we considered lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety criteria. The candidate selected for the purposes of this study is a preinsulated, aluminum-jacketed, fiberglass epoxy pipe that has been used extensively in Alaskan and Antarctic ser- vices. The bulk of the piping system is made up of 6-in. and 2-in. pipe sections. Each section is a 20-ft spool insulated with 2 in. of poly- urethane foam, identical in design to the pipe described for Barrow (Sec. III). Initially, we considered installation of underground piping. Instal- lation of such systems in permafrost or cyclically freezing soil is a major problem, however, both in terms of man-hours required and of eventual damage to the utilidor or piping system. Burying a piping system that would distribute water at temperatures up to 180°F almost certainly implies the use of utilidors, utiliducts, and a forced-air utilidor cooling system to maintain the integrity of the permafrost. Failures in the underground piping system would likely go undetected for an extended period. Consequently, because of the relatively high temperature of the water, a high probability exists that extensive local melting of the permafrost would occur. The resultant subsidence phenomenon could cause extensive damage to the district heating system, as well as possible collapse of ground and structural foundations in the immediate area. We estimate that the cost of installing a utilidor system would be in the neighborhood of 108 $2900 per house (CHM Hill, 1976). Because of the likelihood of damage from undetected failures, and because of the high cost of installation, we do not recommend an underground piping system for Nome. Most of the structures in Nome are built to withstand frost heave, with the floor raised off the ground, supported by framing. Generally, enough subfloor space exists to accommodate a 6-in. or 8-in. outside diameter pipe. For the purposes of cost optimization, the district- heating distribution piping is considered to run directly beneath the structures (see Fig. 23). Piping connections made near or under the struc- tures would include tees, reducers, and cap fittings. Individual user con- nections to the hot and return distribution lines could be easily installed above-ground. We estimate that the distribution subsystem would be supported by a system of wooden cradles with pipe supports and slide plates. We have conducted our cost estimates on the basis of using thrust blocks, placed and anchored to support dummy stub connections where the piping changes direction. The piping system could cross narrow streets by means of a simple riser and downcomer separated by a supported, relatively short, straight spool. For wider streets, the geothermal heating lines might be laid underground in a slightly oversized culvert section. BASE-CASE SYSTEM COSTS Table 10 displays the detailed costs of the Nome system. The table below summarizes the life-cycle costs. Total capital investment $ 32,063,000 3C-yr ownership cost (at 102) 128,252,000 Average annual ownership cost 4,275,000 Average annual cost 5,313,000 BASE-CASE SYSTEM BENEFITS Figure 24 compares 30-yr annual costs for the Nome svstem with alternative conventional-energy costs. It is apparent that the Nome system becomes cost-effective only if the price of conventional fuel (stove oil) rises rapidly, or if additional uses are made which have an 109 Table 10 NOME BASE-CASE COSTS (in $ thousands) YEAR COST CATEGORY ne eee 1 2 3 4 5-30 Total 1 Sn nn ees ee 1. RESEARCH AND DEVELOPMENT | COST (RDC) 1.1 Survey 8 1.2 Site Selection 8 1.3 Permits 5 5 ' ; TOTAL RDC 21 | 21 : ——_—_ 2. PRODUCTION COST (PC) 2.1 Drilling and Well Preparation 2.1.1 Material 15,000/12,349 27,349 2.1.2 Labor 2.1.3 Mobilization 90 90 2.1.4 Loss and Repair 150 123 273 2.1.5 Rig Relocation 100 53 153 2.2 Wellhead 2.2.1 Material 300 318 618 2.2.2 Labor 60 64 124 2.2.3 Transportation 39 40 79 2.3 Utilidor 800 502 1,302 2.4 Distribution 2.4.1 Material 500 356 856 2.4.2 Labor 500 385 885 2.4.3 Transportation 50 34 84 TOTAL PC 17,499 ha, 224 31,723 (continued on next page) 110 Table 10 (continued) COST CATEGORY bie te 1 2 | 3 4 5-30 Total _ | —_+ 3. INITIAL DEVELOPMENT COST (IDC) 3.1 System Start-Up 3.3.1 Training 8 8 16 3.3.2 Technical Data 6 6 3.2 Installation--Checkout 3.2.1 Initial Spares Stockage 95 95 3.3.2 Labor 82 43 125 3.3. Demobilization 77 | 77 jot al TOTAL IDC 191 51 77 319 —t fi festa t i 4. RECURRING COST (RC) 1 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory 10) ll 12 710 743 Replenishment 4.1.2 Labor 139| 201 213112, 600| 13,153 1 | | | TOTAL RC I 149 212 225 | 13,896 OWNERSHIP COST: RDC 21 21 PC 17,499 14,224 | 31,723 Ipc 191 51 77 319 RC 149 212 225/13,153] 13,739 \ — | GRAND TOTAL 17,711) 14,424 289 225113,153} 45,802 111 ctl Annual Cost (millions) ————— Geothermal system base year 1980 1985 1990 1995 2000 2005 2010 Fig. 24--Increase in oil price for space heating compared with the cost of a geothermal system economic or social benefit. The remainder of this subsection discusses possible added uses. Greenhouse Agriculture Because of the severe climate in Nome, produce is virtually unavail- able most of the year. Since demand far exceeds supply, we consider the use of geothermal energy for greenhouse heating to be a very practical way of increasing produce production in the spring and summer seasons when district heating requirements are low. To determine if an adequate supply of energy is available, we have developed some preliminary estimates of thermal power required to support a geothermally heated greenhouse. Greenhouse Power Estimate It is very difficult to maintain constant temperature within a green- house because of the structure's inherently rapid temperature response to changes in solar radiation. As conduction, convection, and radiation heat flows change, conventional greenhouses must be alternately heated and cooled. In addition, coordinated ventilation/temperature control systems must be utilized to maintain proper humidity levels. Greenhouse cooling systems are not required in Nome because temperatures can be controlled by operation of air dampers to regulate the influx of cool air. The design of the greenhouse heating system must be based on daily minimum temperature, minimum crop-sustaining temperature, and greenhouse size. Humidity can be controlled by operation of the manual or automatically modulated dampers. We have based our heating requirements on a minimum seasonal dry-bulb temperature (see Table 11) and a design wind speed of 15 mph. We have chosen a minimum temperature of 19°F for Nome, to provide a six-month growing season. These greenhouse systems then can be operated seasonally when relatively little district heating is required. Heat-transfer losses from our theoretical greenhouse are calculated according to the assumption that double-paned glass will be used. We pointed out above that fluctuations in greenhouse temperature dur- ing the day respond very quickly to variations in insolation, and that some modulation of air dampers may be required to control greenhouse 113 temperature and humidity. It is obvious that a greenhouse energy balance during daylight hours is a function of conduction, convection, radiation, and infiltration energy-transfer mechanisms. But maximum required heating load will occur at night, when solar radiation is zero, and outside ambient air temperature is at a minimum. Based on an analysis identical to that of Kiana, an expected heat loss has been developed. The calculations for Nome have been omitted for the sake of brevity; but with an outside tempera- ture of 479°R, we have determined that a 20-ft x 20-ft greenhouse requires 38,722 Btu/hr, or 1.134 x 107? MW for proper operation. Based on the system proposed for Nome, we conclude that excess geothermal capacity (9.72 MW x 0.13) is 1.26 MW, which is sufficient to heat over 100 greenhouses. This capacity is far in excess of that required by the town of Nome. Table 11 MINIMUM DRY-BULB TEMPERATURES AT NOME ? ——. Month Average Minimum Temperature Lowest Temperature Dm January - 8.7 -27 February -25.9 -39 March - 6.6 -31 April - 1.0 -20 May 25.6 19 June 36.2 27 July 41.4 31 August 44.7 36 September 38.6 29 October 24.2 7 November 9.0 -15 December 1.1 -22 nr 71976 data from National Oceanic and Atmospheric Administration, Environmental Data Service, National Climatic Center, Asheville, North Carolina. 114 Aquaculture Nome is not sufficiently near any fresh-water sources to permit realistic consideration of aquaculture. Waste Treatment Geothermal heat could be useful in speeding biodegradation in Nome's sewage-treatment system. Ideally, geothermally supported greenhouses could utilize the composted material and sludge that are typical byproducts of solid-waste processing. Bath Houses and Swimming Facilities The excess potential of the Nome system, approximately 8 MW during the summer months, is sufficient to support numerous community facilities of this type. COST-BENEFIT DISCUSSION Nome combines several features that make it the most attractive site studied for a high-visibility demonstration of geothermal potential. Although the geothermal system is not clearly superior, it is cost-+com- petitive during later stages of system life. Adding other services and applications should further enhance the total benefits of the geothermal system. Nome is sufficiently populous to support these additional uses and to provide a labor base should industrial uses prove economically feasible. 115 VIII. WRANGELL THE TOWN OF WRANGELL Wrangell (and Southeast Alaska in general) differs strikingly in appearance from the rest of the state. Wrangell nestles against heavily forested foothills at the northwest end of Wrangell Island, facing the Zimovia and Stikine Straits and other islands of the Alexander Archipelago. Fog and low clouds, typical of maritime climate, lend Wrangell a misty aura during much of the year. Because of varied topography, weather conditions around Wrangell are quite localized and can change rapidly. The temperatures vary little and are generally cool (summer, 47° to 65°F; winter, 24° to 37°F; extremes, -10° to 92°F), but permafrost is rare. High humidity, frequent cloud cover, and much precipitation (over 100 in. a year) make this a rain- forest region. Winds are moderate to strong, averaging easterly at 9 kn, with extremes SSE at 42 kn. Channeling effects created by islands and mountains maintain low velocity winds from September through May, becom- ing stronger from May to August. Inversions do occur and, depending on the wind and the location of surrounding mountains, pollution from house heating, cars, utility plants, and the lumber and pulp mills does become a problem. Part of the processing previously handled by the pulp mill has been discontinued because of objections from environmentalists, but local people are divided in their environmental stands. The latitude (54°31'N) sees:less change between summer and winter daylight hours than elsewhere in Alaska, the longest day being 17-1/2 hr, and the shortest, 7 hr. The lingering cloud cover and shadows from neighboring mountains and foothills prevent much of the possible solar radiation from reaching the ground. Very moist and cool ground temperatures slow decomposition in South- east Alaska, and the subsequent lack of aeration and of nitrogen fixation results in very acid, infertile soil. People are able to maintain small home gardens; but there is no large-scale agriculture or domestic grazing land. Erosion where plant growth has been disturbed (e.g., by logging or road building) can lead to slides. The most important forests in this region are Sitka Spruce and Western Hemlock. The local climate allows some of these trees to grow as large as 14 ft in diameter. Also, wet tundra, muskeg, and some alpine tundra are found near Wrangell. Wrangell has elementary and secondary schools, and vocational train- ing facilities, as well as a hospital and clinic with two doctors and a dentist. There are radio, television, and telephone communications. For a population of about 3000 people, approximately 600 jobs are available. Government and transportation are the major employers outside of the lumber and fishing industries. The Tugged coast of this region is icefree all year. The marine environment is rich in nutrients, with water tempera- tures from 42.5° to 45.0°F in winter and 55.0° to 57.0°F in summer. Domestic fishing is mainly for salmon, herring, and halibut. The harvest of pink salmon has declined in the last 15 years while other harvests have remained stable. Foreign commercial fishing previously was legal outside of a 12-mi limit from the Alaska coast; but since March 1, 1977, a 200-mi limit permits only limited takes by foreign fisheries. The potential of aquaculture, mariculture, and hatcheries is being researched by the Alaska Aquaculture Foundation in Wrangell. Although no facilities of this sort now exist near Wrangell, the group hopes to obtain funding for such projects in the near future. The present gross land structure in this region was formed during the Quaternary period by glacial and volcanic activity. Southeast Alaska is generally in a period of glacial retreat at this time. Wrangell is situated on the circum-Pacific seismic belt and has a high potential earth- quake risk. No mining is done on Wrangell Island, but mineral discoveries in "Southeast" include garnet, fluorite, limestone, gold, zinc, lead, copper, silver, palladium, uranium, iron, antimony, molybdenum, beryllium, thorium, chromium, titanium, and nickel. Wrangell has no known petroleum fields but is not far from the Gulf of Alaska Tertiary Petroleum Province. Most known coal beds in this region lie near Juneau. Several thermal springs are close to Wrangell, along the Stikine River. Electricity is provided Wrangell by a 2675-kW diesel generator. Future power is a major concern to the populace. Although electric rates are lower than in Nome and Barrow, the cost is still higher than consumers desire, and available electricity is now quite limited. Fresh surface 118 water in reservoirs supplies most of the town's daily 1,400,000-gal consumption. Producing wells in Wrangell are usually bedrock wells, though some have yielded water from unconsolidated layers. City-provided sewage disposal serves over half of the town. Wrangell is accessible year-round by the ferry (Alaska Marine High- way System) that runs between Seattle and Skagway. Alaska Airlines provides daily (except weekend) jet service. Local charters and air- taxis provide transportation among the islands. Changeable weather con- ditions often prevent Alaska Airlines from stopping in Wrangell, and light aircraft are usually float planes or amphibians (wheels and floats), since they are often forced down far from an airstrip. Freight is brought in by air or barge. Climate The climate of Wrangell is relatively mild compared with that of the other towns in this study. A coastal city, Wrangell has a very high precipitation rate, with an average annual precipitation of 82.4 in. Temperatures range within thirty degrees year-round. The minimum recorded temperature (in January) is 24.5°F, and the mean low temperature is 29.7°F. Annual heating degree days total only 8503;.monthly degree days are de- picted in Fig. 25. Buildings Most buildings in Wrangell are very well insulated and "tight." Relatively good access to suppliers and materials provides Wrangell residents and builders with most modern-day materials at reasonable prices. Averaging 1000 sq ft, most houses are frame structures with sheetrock inner walls and plywood and shiplap outer walls. Fiberglass insulation is used, and windows are thermopane or are fitted with storm windows for winter. Wrangell has approximately 800 residential buildings and 200 commercial buildings (including a hospital, two hotel/motel facilities, two lumber mills, one cannery, one theatre, a senior citizens center, a legion hall, ten churches, a public library, two financial institutions, and a museum). 119 OcT e days Heatine-deare 2500, 2000 1500) —_ > 2 500 Jan Feb Mar Apr May June July Auq Sept Oct Fig. 25--Monthly heating degree days for Wrangell Nov Dec WRANGELL RESOURCE MODEL The Wrangell area is underlain by metamorphic rocks of the Wrangell- Revillagigedo Belt, including phyllites, metawackes, and garnet-bearing quartz-mica schists. The bedrock is generally overlain with fine-grained marine deposits ranging in thickness from zero to thirty feet. Wrangell is located in a region of no permafrost. No known thermal springs exist in Wrangell, although Bailey and Bell Island Hot Springs are located about 50 mi to the southeast and Chief Shakes Hot Springs about 25-mi northeast of town. Since no deep holes have been drilled in the Wrangell area, we have based our assess- ment of the geothermal gradient on gradients in other metamorphic terranes of the Barrovian type. We assume that the gradient at Wrangell is approxi- mately 30°C/km (see Appendix A). The metamorphic rocks underlying Wrangell have very low fracture porosity/permeability. Because of the limited fracture systems, and monolithic nature of the basement rock, we believe no likelihood exists of encountering a useable aquifer at depth. As in Barrow, we believe that the only useable model for Wrangell is a hot, dry-rock system with induced heat extraction. Wrangell is a large town with a population of about 2500. But because it is located in "Southeast," an area of rather mild maritime climate by Alaskan standards, the heating requirements for the town are moderate. As discussed in Appendix E, drilling in Alaska is extremely expensive. To minimize the number of wells required to provide the thermal power for Wrangell, we have modeled our hot, dry-rock resource as a 250°F hydrau- lically induced fissure system with forced-fluid heat extraction. Detailed discussion of the heat-utilization systems, resource life, and cost considerations are presented below. SYSTEM DESIGN We have developed a model that represents a workable implementation scheme for the town of Wrangell, performing our analysis as a preliminary engineering exercise and not as a parametric study of system costs. As in our other investigations, we began our technical investigation of Wrangell by determining the thermal power required for district heating. Based on 121 the specific geothermal resource that we have considered, a preliminary resource utilization model has been developed to site-specific design criteria, in accordance with good engineering practice. We then performed sizing calculations and developed preliminary process specifications for the materials and equipment required for a district heating system in Wrangell. With the help of many vendors, we obtained cost quotations and estimates based on our specifications. Our system design criteria are 1) safety to inhabitants and to the permafrost region, 2) high system reliability, 3) low initial cost, and 4) low O&M and complexity. The resource utilization model is divided into the energy-extraction subsystem and the distribution-piping subsystem. Fig. 26 represents the energy-extraction subsystem; Fig. 27, a preliminary piping distribu- tion subsystem. ENERGY-EXTRACTION SUBSYSTEM Figure 26 shows the preliminary geothermal-energy extraction subsystem. In developing the system, we consider it critical that system safety considerations be given high priority. We assume that the spudding-in, drilling, and mud- and cement-injection procedures are identical to the procedures used by oil-well drillers in a nonpermafrost region. We con- sider high-pressure casing necessary because of the relatively high pres- sure required for hydrofracting and normal system operation. Valve and pipe ratings and end connections are in accordance with ANSI and ASME speci- fications for water service at 1500 psig. The system includes a shell- and-tube counterflow heat exchanger. We determined that a shell-and-tube heat exchanger with a high-pressure rating on the tubes and tubesheets was required for a hot, dry-rock resource application. Fittings and pump casings in the extraction system are also rated for high-pressure service. Cost estimates include allowance for system safety valving and instrumenta- tion, alarms, and control logic devices. We have sized equipment so that flow rates generated by operation of the geothermal system will result in noise levels well within OSHA-specified limits. 122 eet 13200 ft PTE accumulator makeup makeup water tank water pump distribution system circ water pum 122°F " pa wellhead heat exchanger Y district heating distribution drain system headers geo fluid circ pump distribution system Y circ water pump drain downhole heat exchange Fig. 26--Preliminary geothermal-energy extraction gubsystem for Wrangell 124 preliminary wellset location Fig. 27--Preliminary distribution-piping subsystem for Wrangell DISTRIBUTION-PIPING SUBSYSTEM Figure 27 shows the candidate water-distribution system to be used for district heating. Water temperature in the distribution system is not to exceed 180°F. Primary safety criteria are that system pressure be maintained within reasonable limits and that no single piping failure go undetected. To meet the safety criteria, we determined that maximum distribution-subsystem design pressure should not exceed 100 psig. In addition, shutoff capability should be placed at intervals throughout the system. High system reliability is defined as high availability to the users, with provisions for quick repair of system failures at any time of year. We determined that the type of piping to be used in the system must have a history of reliable operation in similar applications. To ensure high reliability, the distribution subsystem is divided into a header system with periodic crossties provided to bypass failures. As in the models for the other towns investigated, all residences are considered to have service connections in parallel so that individual heaters can be operated indepen- dently. We anticipate that at least once in the lifetime of the system the entire secondary loop will be inoperative. Therefore, drain valves at low points in the piping system--necessary for freeze protection--are included in the cost estimate. Low initial cost is a difficult objective to attain in Alaska. To minimize labor and equipment required, we considered lightweight piping systems that require minimal skilled labor for assembly and that meet the reliability and safety criteria. The candidate selected for the purposes of this study is the preinsulated, aluminum-jacketed, fiberglass epoxy pipe described in above discussions of other towns. The bulk of the piping system is made up of 6-in. pipe sections. Each section is a 20-ft spool insulated with 2 in. of polyurethane foam. The pipe spools can be handled easily by two men and assembled by relatively unskilled labor. We consider installation of underground piping practical because Wrangell is not located in a permafrost region. We expect that user connections could be made to the supply and return lines with short risers and service connection lines. The piping could be buried directly beneath the streets as in conventional piping installations. 125 PRESENT FUEL USE AND COSTS Our research indicates that space heating in Wrangell consumed 2,022,000 gal of stove oil in 1976. This consumption translates to a total space-heating cost of $978,600 at then-present rates of $0.484/gal and $0.474/gal of No.-1 and No.2 stove oil, respectively. BASE-CASE SYSTEM COSTS Table 12 details the costs of the Wrangell geothermal system. Total life-cycle costs are as follows: Total capital investment $16,067,000 30-yr ownership cost (at 10%) 64,268,000 Average annual ownership cost 2,142,000 Average annual cost 2,674,000 BASE-CASE SYSTEM BENEFITS Figure 28 displays space-heating fuel expenditures for Wrangell, assuming three alternative rates of price inflation. The Wrangell base- case geothermal system is clearly cost-effective at higher inflation rates. Numerous other uses of geothermal energy may prove attractive in Wrangell, as discussed below. industrial Processing Wrangell's currently operating cannery and lumber mills could be prime customers for geothermally provided heat. We were unable to obtain figures for the heating-fuel use at these operations; but further study of the economies of such implementation are advisable should additional geological evidence be favorable to drilling for the geothermal resource at Wrangell. Aquaculture Hatcheries to increase the number of salmon returning to the Stikine River are needed at Wrangell and would be a suitable application for low- temperature geothermal energy. 126 Table 12 WRANGELL BASE-CASE COSTS (in $ thousands) — YEAR COST CATEGORY -30 Total 1 2 _| 3 4 5-3 an ota 1. RESEARCH AND DEVELOPMENT COST: (RDC) ely Survey 4 4 1.2 Site Selection 4 4 1.3 Permits 5 5 ft pana TOTAL RDC 43 13 2. PRODUCTION COST (PC) 2.1 Drilling and Well Preparation 2.1.1 Material 13,350 13,350 2.1.2 Labor 2.1.3 Mobilization 92 92 2.1.4 Loss and Repair 134 134 2.1.5 Rig Relocation 50 50 2.2 Wellhead 2.2.1 Material 470 470 2.2.2 Labor | 70 70 2.2.3. Transportation 30 \ 30 2.3 Utilidor 40 | 40 2.4 Distribution 2.4.1 Material 844 844 2.4.2 Labor 755 | 755 2.4.3 Transportation 43 43 T r TOTAL PC hs,a78 115,878 (continued on next page) 127 Table 12 (continued) COST CATEGORY 3. INITIAL DEVELOPMENT COST (IDC) 3.1 System Start-Up YEAR & 5-30 Total 3.3.1 Training 8 8 3.3.2 Technical Data 5 i 5 3.2 Installation--Checkout 5 aS S021 gecckage 79 79 3.3.2 Labor 82 82 3.3 Demobilization 52 52 pt Eee eases -————+ TOTAL IDC 226 226 4. RECURRING COST (RC) 4.1 Monitoring, Operation, and Maintenance 4.1.1 Spares Inventory Replenishment . 9 9 532 558 4.1.2 Labor 95 101 107 | 6,336 6,639 OO _sa._.——_— —_|_ TOTAL RC | } 103 110 116 | 6,868] 7,191 sO OWNERSHIP COST: RDC 13 PC 15,828 IDC 226 RC 103 110 116 | 6,868 7,191 Eee ett eee CneCe GRAND TOTAL 16,067 103 110 116 | 6,868 | 23,264 $1 128 671 Annual cost (millions) —-——— Geothermal system base year 1980 1985 1990 1995 2000 2005 2010 Fig. 28--Increase in oil price for space heating in Wrangell compared with the cost of a geothermal system Swimming and Recreational Facilities Wrangell is currently attempting to raise funds for a community swimming pool. Residents of the community express a great need for recreational facilities and tourist attractions. A geothermally heated spa could be a possible tourist attraction for this town. Agriculture Greenhouses and soil improvement, facilitated by geothermal heat, would be welcomed by the residents of Wrangell, though such uses are not as significant here as are the above applications. DISCUSSION OF COSTS AND BENEFITS Of the six sites studied, Wrangell is the most appropriate for a demonstration if cost-effectiveness is the sole criterion for decision- making. Unfortunately, Wrangell does not offer the opportunities for an "Arctic" demonstration afforded by the other towns, nor does it appear to need the low-cost energy as much as other sites. The Wrangell case may be particularly illuminating in considering a "lower-48" demonstration. Our estimates of geothermal-system costs apply Alaska drilling rates to the Wrangell system; that it emerges cost-com- petitive in spite of this handicap leads one to speculate that northerly "“lower-48" communities may find local-gradient geothermal resources most attractive for space heating. Towns and small cities in the coterminous United States will not be subject to exorbitant drilling costs typical of Alaska, yet many have more severe climates than Wrangell. 130 SELECTED BIBLIOGRAPHY ASHRAE, Handbook of Fundamentals, American Society of Heating, Refrigera- ting, and Air-Conditioning Engineers, Inc., New York, 1959. ----- , Gutde and Data Book, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., New York, 1972. ----- , Handbook of Fundamentals, American Society of Heating, Refrigera- ting, and Air-Conditioning Engineers, Inc., New York, 1977. -----, Systems, American Society of Heating, Refrigerating, and Air- Conditioning Engineers, Inc., New York, 1973. Barish, N., Heonomte Analysts, McGraw-Hill Book Co., Inc., New York, 1962. Beck, R. W. and Associates, Energy Study for Barrow, Alaska, Denver, Colorado, August 1977. Berreman, G. D., "Inquiry into Community Integration in an Aleutian Village," American Anthropologist, 67, 1964. ----- » "Aleut Reference Group Alienation, Mobility, and Acculturation," American Anthropologist, 67, 1964. Blair, A., et al., LASL Hot Dry Rock Geothermal Project, Progress Report LA-6525-PR, Los Alamos Scientific Laboratory, October 1976. Bloomster, C. H., GEOCOST: A Computer Program for Geothermal Cost Analysis, BNWL-1888, Battelle Pacific Northwest Laboratories, 1975. Bodvarsson, G., "Geothermal Resource Energetics," Geothermics, Vol. 2, No. 3, September 1974, p. 83. Boersma, L., et al., A Systems Analysts of the Zconomte Utiltzation of Warm Water Discharge from Power Generating Stattons, Oregon State University, Corvallis, Oregon, 1974. Carlson, A. R., "Comparative Unit Fuel Cost for Equivalent Dollar Net Heat Production" (P-1152), Butlding in Alaska, Cooperative Extension Service, University of Alaska, Fairbanks, March 1976. Chance, N. A., The Eskimo of North Alaska, Holt, Rinehart, and Winston, 1966. Chapman, A. J., Heat Transfer, 2nd ed., The Macmillan Co., New York, 1967. Dalton, G., "Primitive Money," American Anthropologist, 67, 1965. Flow of Flutds through Valves, Fittings, and Pipe, Technical Paper No. 410, The Crane Co., New York, 1969. Graburn, N. H., and B. S. Strong, Cirewnvolar Peo Perspective, Goodyear Publishing Co., Inc., 1973. 131 Green, M. A., and H. Pines, Program GEOTHM: A Thermodynamic Process Pro- gram Sor Geothermal Power Plant Cyeles, LBL 3060, Lawrence Berkeley Laboratory, 1974. Harper, K., private communication, Public Health Service, Division of Environmental Health, August 1977. Howard, J. H. (ed.), Present Status and Future Prospects for Nonelectrical Uses of Geothermal Resources, UCRL-51926, Lawrence Livermore Laboratory, 1975. Jones, D. M., Aleuts in Transition, A Comparison of Two Villages, University of Washington Press, 1976. Kreith, F., Prinetples of Heat Transfer, 2nd ed., International Textbook Co., Scranton, Pennsylvania. Lachenbruch, A., private communication, USGS, October 1977. Levi-Strauss, C., La Pensee Sauvage, Plon, Paris, 1962. McFeat, T., Indians of the Worth Pacific Coast, University of Washington Press, 1967. Merrill, A. L., and B. K. Watt, Energy Value of Foods . .. Basis and Derivations, Agricultural Handbook No. 74, U.S. Department of Agri- culture, February 1973. Mishan, E. J., "Cost-Benefit Rules for Poorer Countries," Canadian Journal of Eeconomtes, 10, February 1971. Nash, M., "The Organization of Economic Life," in Horizons in Anthropology, S. Tax (ed.), Aldine Publishing Co., 1964. National Academy of Sciences, Technology: Processes of Assessment and Choice, U.S. Government Printing Office, 1969. Oswalt, W. H., Alaskan Eskimos, Chandler Publishing Co., 1967. Pokrovsky, A. A., "Qualitative and Quantitative Aspects of Nutrition," Impact of Setenee on Society, XX, July-September 1970. r Ransom, J. E., "The Aleut Language and Anthropology," Explorer's Journal, September 1975. Review of Business and Economie Conditions, Vol. V, No. 3, Institute for Social, Economic, and Government Research, University of Alaska, Fairbanks, 1968. Selkregg, L. L., Alaskan Regional Profiles, Arctic Environmental Informa- tion and Data Center, University of Alaska, 1975. 132 Severson, E. N., Alaska Agricultural Statistics, Alaska Crop and Livestock Reporting Service, June 1975. ----- » Alaska Agricultural Statistics, Alaska Crop and Livestock Report- ing Service, June 1976. Tester, J., and H. Murphy, private communications, Los Alamos Scientific Laboratory, November 1977. VanStone, J. W., Athapaskan Adaptations, Hunters and Fishermen of the Subaretie Forests, Aldine Publishing Co., 1974. Weizenbaum, J., Computer Power and Human Reason, from Judgment to Calcula- tion, W. H. Freeman and Co., San Francisco, 1976. Whorf, B. L., Language, Thought, and Reality, John Wiley and Sons, 1956. Yee, W. C., Agrtcultural and Aquacultural Uses of Waste Heat, ORNL-4797, Oak Ridge National Laboratory, 1972. 133 Appendix A THE GEOLOGIC SETTING AND GEOTHERMAL POTENTIAL OF STIX ALASKAN TOWNS AND VILLAGES Prepared by Robert B. Forbes, Consulting Geologist Alaskan Geological & Geophysical Consultants INTRODUCTION This report has benefited from hundreds of references on bedrock and surficial geology, in addition to site-specific knowledge of the author in all areas other than Huslia. It has been handicapped by a paucity of subsurface geothermal data at Nome, Kiana, Wrangell and Nikolski. Only a few key references have been cited, as compilation of all sources would have demanded additional time and expense. Where subsurface geothermal data were not available, reason- able gradients were selected for models, based on data from localities in similar geologic settings. In the case of metamorphic terranes, an average gradient of 30°C was used, based on measurements taken in similar metamorphic terranes on a world-wide scale. Popular opinion would suggest that heat flow and geothermal gradients should be high along the "Ring of Fire", coincident with the chain of volcanoes forming the backbone of the Aleutian Archipelago and the Alaska Peninsula. How- ever, downhole thermal measurements taken in test wells along the volcanic line have shown that there is a large variance in gradients at various localities, ranging from very low to moderately high (e.g. 16 - 44°C/km). Naturally, test wells avoid the flanks of obvious volcanoes, and we assume that we could increase our "batting average" if we were to deliberately: drill volcanic targets of very young age. The point I wish to make is that no guarantees of high geothermal gradients accompany the drilling of test holes at large step-out distances between active or inactive volcanoes along the Alaskan segment of the circum-Pacific volcanic belt. I have suggested that the Cape Espenberg model be used for Nikolski, as the subsurface geology appears to be quite similar A-2 to that which we might expect to encounter in a test well drilled from a site within Nikolski village. There is, of course, no guarantee that the geothermal gradient is the same at the two localities. However, the gradient measured in the Cape Espenberg test well is not excessively high or low, and should serve as a conservative model for evaluation of the concept. This model is not suggested for drilling experiments to the north, near Geyser Bight and Okmok Caldera. WRANGELL Geologic Setting Bedrock: The Wrangell area is underlain by metamorphic rocks of the Wrangell-Revillagigedo belt, including phyllites, meta- wackes and garnet bearing quartz-mica schists. The schist terrane is intruded by small bodies of quartz diorite, which tend to parallel the layering and schistosity of the enclosing schists (lemke, 1974). Surficial deposits: Bedrock is overlain by fine-grained marine deposits (clays, silts and sands), and beach deposits (sands and gravels), overlain by muskeg. The thickness of the surficial deposits ranges from zero to 30 feet. There is no permafrost. Bedrock structure: The metamorphic rocks are sub-isoclinally folded, with axial planes which dip to the northeast (see Fig. 1A, below). Southwest Northeast Fig. 1A--Idealized sub-isoclinal structure in the Wrangell area. Geothermal Data Thermal springs: Although there are no thermal springs in the Wrangell area, Bailey and Bell Island Hot Springs are located approximately 50 miles to the southeast, and Chief Shakes Hot Spring is located about 25 miles northeast of Wrangell. Heat_flow and geothermal gradients: No deep holes have been drilled in the Wrangell area, and no downhole geothermal data are available. Based on measured geothermal gradients in other metamorphic terranes of the Barrovian type, we estimate that the geothermal gradient will be around 30°C/km. Geothermal Targets And Drilling Parameters Targets: None of the rock units in the Wrangell-Revillagigedo schists can be expected to offer inter-granular porosity/ permeability potential. Potential targets will be confined to fracture porosity in the more competent units such as meta- wackes and quartzites. Possible seawater encroachment offers interesting potential and possible drilling problems. The drill site would be located relatively close to the beachline, and the hole would be spudded in about 50 feet above sea level if it is located within the town of Wrangell. Drilling parameters: The rig would be set up on a muskeg covered site, but the coveris relatively-thin,and the underlying sands and gravels are competent. With the exception of the ini- tial 10-30 feet of unconsolidated sediments, the hole will be drilled through metamorphic rocks of the Wrangell—-Revillagigedo terrane. Drilling problems will include slower drilling rates, down-dip drifting of the bit and possible seawater encroachment. To obtain 100° temperatures, we anticipate a 10,800 foot hole. The section which would be cut by the hole is diagramatically shown in Fig. 2A. He) ' ur Logistics: The drill rig and associated equipment would be transported to Wrangell by ship, and off-loaded to trucks which could transport them to the site. Site preparations would be routine. Crews could be accommodated in the town of Wrangell. = 0-30 ft. marine sediments & beach deposits sea level core 1000' = 2000! - 3000! cg 4000" — metamorphic rocks including phyllites, meta-wackes & , — 3000 garnet-mica schists 6000" = 7000' = sooo" — 9000' i 10,000" =— 11,000" =— Fig. 2A-- Generalized sub-surface geologic section of the Wrangell area, Alaska. Geothermal Models Based on an assumed geothermal gradient of approximately 30°C/km in the underlying metamorphic terrane, and the accompanying lack of porous aquifers, we propose a hot-dry rock model. Possible fracture porosity in the more competent rock units could promote fracture communication between paired holes in induced systems. NIKOLSKI Geologic Setting Bedrock: The Nikolski area is underlain by Tertiary sedi- mentary rocks including bedded siltstones, sandstones, and subordinate tuffs (Figs. 3A and 4A). A mile to the north, the Tertiary sediments are intruded by a mafic intrusive complex which underlies "High Hills," which is topped by the "White Alice" station (Fig. 5A). Approximately 1/2 mile south of the village, fine-grained granodiorite is exposed in the sea cliffs on the west side of the island. The sediments have been baked near the contacts with the intrusives. Steeply dipping to vertical basalt dikes also cut the sediments. Such dikes are well exposed along the road from the village to the White Alice Station. According to Byers (1959), the sediments are also cut by and/or intercalated with keratophyres and albitized diabase sills. The Tertiary section composes the basement of the island, and to the northeast these rocks are unconformably overlain by the younger volcanic piles of flows and pyroclastics associated with Recheschnoi, Vsevidof and Okmok volcanoes. Surficial deposits: These deposits range in age from late Pleistocene to recent, including till, glacial outwash, beach deposits, dune sand, talus and alluvium. The village of Nikolski is located on a thin blanket (20-40 feet) of beach sand and gravel which in turn rests on the flat surface of the Nikolski plain which is an old wave-cut surface on bedrock. The sands and gravels are water bearing, and the village water system obtains water from shallow wells driven to a depth of 20 to 30 feet. sea level -- ms} = surficial deposits 1000' = mw ath Ka 1 { 2000' = 7 G 3000' = y quartz diorite intrusives 4000 . <a ee 5000' = Fo~ tus diabase sills and 6000" =- keratophyres bs 7000' = argillites 8000 ' - gooo' = 10,000' - <«<¢ < i tuffaceous sediments Fig. 3A--Diagramatic Composite section; Nikolski, Geyser Bight and Hot Springs Cove areas, Umnak Island, Alaska. Note: Drilling rate will be relatively fast in tuffs and argillites, and slow in diabase, keratophyre and quartz diorite. OT-¥ Fig. 4A--Gently dipping Tertiary siltstones and tuffs exposed in a road cut between Nikolski and the White Alice site on High Hill. TI-W Fig. 5A--High Hill and the White Alice site as viewed from Nikolski. High Hill is underlain by a mafic intru- sive complex which cuts the Tertiary sedimentary section. Bedrock structure: Layered rocks in the complex have a north- westerly strike, and dips have been reported from horizontal to vertical . Dips at the head of Driftwood Bay suggest a southeasterly plunging anticline. Near Nikolski, however, the dips are nearly horizontal. Geothermal Data Thermal springs: Thermal springs are located at Geyser Bight, Hot Springs Cove, Okmok Caldera and in the small valley that drains eastward across the narrowest part of Umnak Island. Sinter deposits and geothermometry indicate that sub-surface reservoir temperatures may be above 150°C for some of the Geyser Bight and Hot Springs Cove springs, and between 90° and 150°C for some of the springs in Okmok Caldera.- Heat_flow and geothermal-gradients: No deep holes have been drilled on Umnak Island, and no downhole geothermal data are available. The 1945 eruption of Okmok volcano and the 1883, 1906-1910 and 1926-1927 eruptions of nearby Bogoslof volcano indicate that magma has reached the upper levels of the vol- canic conduit systems in very recent time. Rhyolite domes of post-glacial age, at the head of Russian Bay, also suggest that silicic volcanism has occured in this area in the last few thousand years. Sass and Monroe (1970) calculated heat flow values from geothermal measurements taken in four deep drill holes on Amchitka Island, and obtained an equilibrium heat flow of 1.3 HFU. Gradients measured in the holes ranged from 20° to 35°C/im, and increased with depth. This increase was apparently due to water circulation in the upper parts of the holes. The deeper of the four drill holes bottomed out at 1158 meters, with a maximum temperature of about 40°C. Although Amchitka Island is about 500 miles to the southwest of Umnak, these data are the best we have at present. A-12 Geothermal Targets And Drilling Parameters Targets: The sinter-depositing thermal springs in Geyser Bight and Hot Springs Cove are good indicators of sub—sur- face hot water systems with temperatures above 150°C (White and Williams, 1976). The proximity of Holocene (“10,000 years) rhyolite domes is also encouraging. The geologic map (Byers, 1959) indicates that following a relatively thin layer of surficial deposits, a drill hole would penetrate the older basement rocks. The proposed target would be a geothermal anomaly associated with a sub-surface magma reservoir or cooling pluton related to the rhyolite domes. Due to the lack of heat flow and gradient measurements, there is no reliable way to estimate the depth of such a target..... but 2 km is selected as a reasonable depth. The basement rocks are somewhat altered on the north end of the island, as they have been zeolitized and partially re placed by carbonate and silica. Based on lithologic descrip- tions, intergranular porosity and permeability will be marginal in these rocks. The most likely target would be the possible intersection of porous sandstone or tuffaceous aquifers near the subsurface extension of the silicious domes or in an area of high heat flow adjacent to the thermal springs. However, it is more likely that the aquifers, if found, will be due to fracture porosity in volcanics or argillites. Drilling at Nikolski would offer more risk than at Geyser Bight or Hot Springs Cove, as there are no hot springs or silicic domes near Nikolski village. Seawater intrusion is a possible complication at both sites. However, we can assume that the drill would penetrate Tertiary sandstones, siltstones, tuffaceous sediments and rare basaltic (diabasic) dikes and sills. Although we have no measured heat flow or thermal gradient data on Umnak Island, we think it is logical to deduce that the gradient is perturbed near the silicic domes and hot springs, Arl3 and that the actual gradient may be around 40°C/kn. Although the subsurface gradient may be less at Nikolski, based on surface evidence....we will also hypothesize that the quartz dioritic intrusives are very young (410,000,000 years), and that the gradient is also somewhat perturbed near Nikolski. If we assume that a hot water pipeline from Geyser Bight to Nikolski would be uneconomic, then we must drill near the Nikolski village site. Because of the lack of subsurface information at Nikolski, we have chosen a model which may be geologically similar to Nikolski, based on lithology, geo- thermal gradient and aquifers. This model is based on data from the Cape Espenberg #1 well, drilled west of Kotzebue, Alaska. Logistics: The drill rig and associated equipment would be transported to Umnak Island by ship, and lightered ashore. Landings may be difficult. Camp facilities will have to be constructed for crews. Geothermal Models The Espenberg model: Under the provisions of a development agreement with the NANA Regional Corporation, the Standard Oil Company of California drilled two wells in the Kotzebue area during the winter of 1974-1975 (Cape Espenberg #1; Nimiuk Pt. #1). Both of the wells were "dry holes", as no indications of gas or oil were detected in either well. Both wells are of unusual interest, however, as they have provided new information on the subsurface geology of the area, including the presence of a rather thick section or coal- bearing Tertiary rocks which contain salt water—bearing aquifers and a geothermal gradient which is higher than- that in many sedimentary sections. The Espenberg well reached a total depth of 8373 feet, with a bottom hole temperature of 161°F (72°C). Crystalline basement rocks were intersected at approximately 8100 feet, including marbles, calc-schists and phyllites. The schists appear to have been hornfelsed by intrusives. The crystalline basement is overlain by a basal sequence of conglomerate and sandstones, which is succeeded by tuffaceous volcanics inter- bedded with sandstones and siltstones. The tuffs leave the section at about 5500 feet, and coal-bearing sandstones, conglomerates and siltstones make up the rest of the section. Both conglomerates and coal beds decrease.up section in the drill hole. The measured geothermal gradient is 28°C/kn. Tests were conducted on four zones in the Espenberg well. Three were either unsuccessful or dry tests. Formation test #2, conducted on a zone near the bottom of the well at 7914- 8128 feet, resulted in no oil or gas, but a 7414-foot rise of salt water mixed with sand and md, which occupied the hole in three hours and fifty minutes. This zone is apparently an excellent saltwater aquifer. A subsurface section for the Cape Espenberg #1 well is shown in Fig. 6A; a deduced section for Nikolski is dia- grammed in Fig. 3A, p. A-9. GENERALIZED GEOLOGIC SECTION CAPE ESPENBERG #4 WELL 1000’ SANDSTONES LIGNITE SANDSTONES SHALE 2000 SANDSTONE LIGNITE LIGNITE SANDSTONES COARSE SAND & CONGLOMERATE 3000' SANDSTONES CONGLOMERATE LIGNITE CONGLOMERATE SANDSTONE 4000 COAL, SHALE & CONGLOMERATE 5000 INTERCALATED BASALTS & SANDSTONES BASALT 6000’ TUFF CARBONATE TUFF fe 7000' TUFF W/INTERCALATED SANDSTONE TUFF, AGGLOMERATE & CONGLOMERATE SANDSTONES & SHALE MARBLE, CALC - SCHIST & PHYLLITE (HORNFELSED & PYRITIZED ‘| NOME Geologic Setting Bedrock: The Nome area is underlain by metamorphic rocks of the Nome Group, including inter-layered greenschists, quartz-mica and garnet-mica schists and schistose marbles. Surficial deposits: Bedrock is overlain by glacial and marine sedimentary deposits ranging in thickness from 30 to 80 feet. The sediments are mantled by tundra vege- tation. North of the present beachline, the sediments are perennially frozen below the mobile layer. Permafrost is believed to extend down to depth of 800 feet in the sub- surface. Bedrock structure: The crystalline schists of the Nome Group are complexly folded, with fold styles ranging from sub—isoclinal to isoclinal (see Fig. 7A, below). 2 é isoclinal sub—isoclinal Fig. 7A--Sub-isoclinal and isoclinal fold styles. Geothermal Data Thermal springs: Although there are no thermal springs in ——— eS Oe the Nome area, Pilgrim and Serpentine hot springs are located 40 and 100 miles north of Nome, respectively. Heat_flow and geothermal_gradients: No deep holes have been drilled in the Nome area, and no downhole geothermal data are available. Based on known geothermal gradients in basement rocks elsewhere, however, we will assume that the geothermal gradient is approximately 30°C/im. Geothermal Targets And Drilling Parameters Targets: None of the rock units in the Nome Group can be expected to offer inter-granular porosity/permeability po- tential. Rather, fracture porosity in the more competent units such as marbles and quartzites constitutes the only known reservoir potential. Considering the overlying perma- frost zone, however, there is no guarantee that such fracture Systems if found, will contain water at the desired depth. Possible seawater encroachment offers interesting potential, and possible drilling problems. The drill site would be located relatively close to the beachline, and the hole would be spudded in at about 50 feet above sea level. The warming effect of seawater perturbs the permafrost zone in coastal areas of Alaska, and it is possible that this effect might allow seawater to enter fracture systems in the underlying bedrock adjacent to the coastline. Drilling parameters: The rig would be set up on a tundra site, and the usual drilling pad and permafrost techniques would apply. With the exception of the first 30-80 feet of unconsolidated sediment, the hole will be drilled through metamorphic rocks of the Nome Group. Drilling problems will include the slower drilling rates encountered in crystalline rocks, down-dip drifting of the bit and possible seawater encroachment. To obtain 100°C temperatures, we anticipate a 10,800 foot hole. The section which would be cut by the drill is diagramatically shown in Fis. 8A. A-18 A Pie — 30'-80'glacial & marine sediments sea level 1000! Y \ — maximum depth of permafrost 2000'_ x SSN WSEAS aiullis a crystalline schists of the Nome Group 6000" = we mee g000'— Ss 9000'= ae 10,0002 Yee 11,800+ Fig. 8A--Diagramatic subsurface geologic section of the Nome area, Alaska. Logistics: The drill rig and associated equipment would be shipped to Nome via barge and lightered into the Port of Nome. The usual site preparations for drilling and spudding into permafrost would be required. Crews could be accommodated in the City of Nome. Geothermal Models We have no deep hole data in the Nome area, so we suggest a working geothermal gradient of 30°C/km....8 reasonable gradient for regional metamorphic terranes. The Nome Group is too highly recrystallized for remnant porosity in the metasediments, although fracture porosity may exist at depth in some of the more massive metaigenous rock units in the section. The model assumes hot—-dry rock conditions, and no in- situ fluids (an induced system). HUSLIA Geologic Setting Bedrock: The Huslia area is underlain by a thick section of Cretaceous marine and non-marine sedimentary rocks, including greywackes, mudstones, sandstones, shales and conglomerates. The non-marine sandstones and conglomerates are frequently associated with low grade coal seams. These rocks are widely distributed in the sub-surface of the lower Yukon and Kobuk-Koyukuk basins. Huslia is located near the contact between these rocks (Nulato Formation) and a se— quence of Late Cretaceous-Early Tertiary felsic volcanic rocks which overlie the Nulato Formation. The volcanics crop out to the south in a limited area bounded by the ‘large bend in the Koyukuk River (Patton, 1973). Surficial deposits: Bedrock is overlain by 50-100 feet of alluvial silts and sands deposited by the Koyukuk River, plus a shallow blanket of wind-deposited silt. The surface is mantled by tundra vegetation. and fold styles range from open-upright to asymmetrical. The folds tend to be tightly appressed, and frequently bounded by small faults derived from shearing off of the lower limbs. Evidence from the Nulato #1 dry hole drilled by Benedum & Associates approximately 80 miles southwest of Huslia, sug- gested repetition of the section from thrust-faulting. Bedrock structure: Fold axes have northeasterly trends, Geothermal Data Thermal springs: Thermal springs are located near Tunalkten See ee ee Lake, 12 miles northeast of Hughes; and near Deniktow Ridge on the north side of Hot Springs Creek, five miles from the Koyukuk River (65°55'N/155°0QW). No data are available for these springs. However, we do know that Tunalkten springs issue from greywacke bedrock. Heat_flow and geothermal gradients: The Nulato #1 drill hole bottomed out at 12,015 feet. The bottom hole temper- ature was 154°F (86°C), and the gradient was 18.6°C/im. A hole drilled at Huslia would penetrate similar rocks, and these data are applicable to target assessment. Geothermal Targets And Drilling Parameters Targets: Although the Nulato #1 hole was drilled near an oil seep, no oil or gas was found in commercial quantities. The greywackes which dominated the section had very low porosities (e.g. 7% porosity), and few reservoir rocks were cut by the hole. Many fractures were filled by calcite, which reduced the probability of obtaining fracture porosity. However, some sands were intersected by the hole, and one could hope to encounter a reasonably thick and porous sand zone as a reservoir. Various studies indicate that similar Cretaceous rocks compose subsurface sections up to at least 20,000 feet throughout the region; so regardless of drilling site location, one could expect to penetrate similar rocks in this part of the basin. In this case, we could expect to drill to 12,000 feet to obtain go°c, with a rather low proba- bility of obtaining a good reservoir. Drilling parameters: The rig would be set up on a tundra site, and the usual drilling pad and permafrost techniques would apply. The Nulato #1 crew encountered hole allignment problems, and complained that the drilling rates were un- usually slow for sediments, regardless of bit design. The section which would be cut by the hole is shown in Fig. 9A. Logistics: The rig and associated equipment would be shipped by barge.up the Yukon, and on up the Koyukuk River to Huslia. The usual site preparation for drilling and spudding in to permafrost terrane would be required. A camp would have to be constructed for the crews, some dis— tance from the village. 50-100 ft. surficial deposits sandstone, siltstone“& mudstone greywacke 8000! 9000! 10,000! 11,000! 12,000' Fig. 9A--Diagramatic sub-surface geologic section of the Huslia area, Alaska. He) ' tw Wo Geothermal Models It is reasonable to assume that the geothermal gradient under Huslia would be similar to that measured in the Nu- lato #1 test well, as geologic mapping indicates that the two localities are underlain by the same formational rock units. The relatively low geothermal gradient (18-20°C/tm) would require deep drill holes to obtain minimum working temperatures for both natural and induced hot water systems. Optimistically, we could hope to penetrate a deep aquifer with fair porosity and permeability, which contained a typical connate brine under hydrostatic pressure calculated for such depths and accompanying temperatures. These calcu- lations should be based on an average rock density of 2.4. It is tempting to speculate on the possibility of geopressured reservoirs, but no gas shows were detected in the Nulato #1 test well. The possibility should not be completely re- jected, however, as the Nulato #1 well was drilled in the vicinity of an oil seep. We are left with two choices; (1) a model which rejects possible hot water aquifers at reasonable depths and tempera— tures, and consequent use of the hot-dry rock model, or (2) the presence of a good brine reservoir with the same depth/temperature parameters defined by the Nulato test well. An additional gas drive component would be very helpful, but we cannot defend this variation in the model based on current information. A-24 KIANA Geologic Setting Bedrock: The Kiana area is underlain by crystalline schists of the Brooks Range metamorphic belt, including phyllites, greenschists, quartz-mica schists and blueschists. Surficial deposits: Bedrock is overlain by alluvial. silts, sands and gravels. The surface is mantled by tundra vege- tation. Permafrost is believed to extend to depths of 800 to 1200 feet in the sub-surface. Bedrock structure: The metamorphic rocks are isoclinally to sub—isoclinally folded. The trend is northeasterly, and axial planes of folds dip to the southeast. Geothermal Data Thermal springs: No thermal springs have been reported in Heat_flow and geothermal gradients: No deep holes have been drilled in the area, and no downhole geothermal data are available. Based on geothermal gradients in other metamor- phic terranes, we estimate that the geothermal gradiednt will be around 30°C/kn. Geothermal Targets And Drilling Parameters Targets: None of the rock units in the schist terrane can be expected to have good porosity—-permeability values. Potential targets will be confined to fracture porosity in the more competent units such as greenstones and quartzites. Drilling parameters: The rig would be set up on a tundra site, and the usual drilling pad and permafrost techniques would apply. Kiana is underlain by a considerable thickness of surficial sediments (perhaps 200-300 feet). Following penetration of these sediments, the entire hole will be in crystalline schists. Drilling problems will include the slower drilling rates encountered in crystalline rocks, drifting of the bit and the usual permafrost complications. A geologic section is shown as Fig. 10A. RS = surficial sediments ‘1000' 2000' 3000° © OO* i Brooks Range Schist Terrane -5000' 6000" 7000" = 8000" 9000 10,000° TOANTAATRALIN MUTA oS SS RE Fig. 10A--Diagramatic subsurface geologic section of the Kiana area, Alaska. A-26 Logistics: The drill rig and associated equipment would be transported by barge up the Kobuk River via Kotzebue Sound. The usual site preparations for drilling and spudding into permafrost terrane would be required. Crews could be ac-— commodated in the village, by arrangements with the Blanken- ship Company. Geothermal Models To obtain higher temperatures, for example 70 to 100°c, we anticipate drilling to 7,500-10,800 feet. At these depths, we can expect hot-dry rock conditions in the subsurface schist terrane. However, fracture porosity in some of the more competent units, such as greenstones, might still prevail at greater depth....which would aid in developing fracture communication between two holes in an induced system. A-27 BARROW Geologic Setting Bedrock: The Barrow area is underlain by sand, gravel and clay of the Gubik Formation (60 feet), followed by the Grandstand Formation which includes massive sandstone beds with clay shale partings (250 feet); the Topagoruk Formation containing clay shales and fine-grained sandstones (1,780 feet); the Oumalik Formation containing claystones, silt- stones and shales (725 feet); and a pre-Mesozoic basement of dense black argillite (Collins, 1961) (Robinson, 1964). This section was penetrated by the South Barrow Test Well #1 (see Fig. 11A). — — Gubik Formation ““ Grandstand Formation — Topagoruk Formation 1900' — 2000" = 3000' — —— Oumalik Formation 4000' = 5000" = 6000' — 7000' — —— Basement argillite gooo' — go0oo' — SYS YS) AAA Ash 10,000' — Ce Fig. 11A--Composite geologic section, Barrow area, Alaska. A-782 Surficial deposits: The Gubik Formation, of Pleistocene age, is cemented by interstitial ice. The surface is mantled by tundra vegetation. The tundra is underlain by silt, sand and gravel which may be remnant beach de-—- posits or lag concentrates from deflation of the Gubik Formation. Bedrock structure: The test holes were drilled on the so called "Barrow High" which was first detected by seismic and gravity surveys. Dips range from gentle to steep in the test holes. The top of the argillite basement was penetrated at 3,385 feet. Geothermal Data Thermal springs: There are no thermal springs in the area. Heat_flow and geothermal gradients: Downhole temperature measurements in the South Barrow #1 well, give a gradient of 26°C/km. Heat flow values calculated by Lachenbruch and Sass for this and other drill holes on the North Slope have been low; ranging between 1.2 and 1.8 HFU. Geothermal Targets And Drilling Parameters Targets: Porosity-permeability values were not very encouraging, as determined for cores taken from the South Barrow drill holes with the exception of thin sandstone beds which gave faint shows of oil between 3,045 and 3,165 feet. South Barrow #4 produced gas from both the Jurassic and the argillite. Apparently, the gas was in fracture porosity in the argillite. Considering the required temperatures and measured gradients, the best target would be a highly fractured argillite reservoir at approximately 10,000 feet. A-29 Drilling parameters: The rig would be set up on a tundra site, and the usual permafrost techniques would apply. Permafrost extends to approximately 700 feet in the sub-— surface. Salt water was encountered in most of the South Barrow drill holes, and it is likely that both brines and seawater encroachment are involved. Drilling rates would be reasonably fast,above the argillite. Logistics: The drill rig and associated equipment could be obtained from one of the various operators engaged in drilling in the Prudhoe or Pet. 4 fields. Accommodations for crews are available in the village of Barrow. Geothermal Models Barrow is underlain by the so called "Barrow High", a structural high which brings the basement up to relatively shallow depths under the Barrow area. In this case, base- ment is the argillite which was penetrated by the deeper Barrow test holes. Argillite was penetrated at approximately 3385' in the South Barrow #1 test well, where the bottom hole temperature was 85°F (30°C). This hole was located 1 mile southwest of Barrow village, and about 1500 feet south of the coastline. Although there were faint shows of oil in sandstone beds between 3045 and 3165 feet, formation tests recovered no oil or gas. Gas has been produced for local use from several wells in this area. Brine has been associated with gas blows in at least two test wells. The water chemistry indicates that the waters are probably con- nate brines rather than sea water. The more reliable downhole gradient measurements ob-— tained from the test holes indicates that the average geo- thermal gradient is about 26°C/km under the Barrow area. A-30 Therefore, drilling would have to proceed to about 9000' (2.7 km) to obtain temperatures near 70°C. At that depth, the hole would bottom in the argillite basement terrane. Earlier laboratory tests have shown that the argillite has very poor intergranular porosity and permeability at much Shallower depths than 9000 or more feet. Too, fracture porosity can be expected to decrease with increasing depth; a condition which does not favor the presence of connate or ground water in suitable quantities for a natural system. Under these constraints, the hot-dry rock model appears to be more realistic. REFERENCES Byers, F. M., Jr. (1959) Geology of Umnak and Bogoslof Islands, Aleutian Islands, Alaska; U. S. Geol. Surv. Bull. 1028-L. Collins, Florence Rucker (1961) Core Tests and Test Wells ” Barrow Area, Alaska; U. S. Geol. Surv. Prof. Paper 305-K. Lemke, Richard W. (1974) Reconaissance Engineering Geohogy of the Wrangell Area, Alaska, With Emphasis on Evaluation of Earthquakes and Other Geologic Hazards; U. S. Geo. Surv. Open File Report. Patton, William W. Jr, (1973) Reconnaisance Geology of the Northern Yukon-Koyukuk Province, Alaska; U. S. Geol. Surv. Prof. Paper 774-A. Robinson, Florence M. (1964) Core Tests Simpson Area, Alaska; U. S. Geol. Surv. Prof. Paper 305-L. Sass, J. H. and Monroe, R. J., (1970) Heat Flow From Deep Boreholes on Two Island Areas; Jour. Geophys. Res., V. 75, No. 23, P. 4387-4395. White, D. E. and Williams, D. L. (1975) Assessment of Geothermal Resources of the United States - 1975; U. S. Geological Survey Circular #726. A-32 Appendix B HOT, DRY-ROCK RESOURCE LIFE These calculations describing resource thermal capacity are based on an annual fixed load for each town. Since loads will vary on a sea- sonal basis, we expect that real rock temperature will fluctuate slightly from our expression for r(t). The periodicity of T will probably drop heat extraction efficiency because See aeiae ull the system will increase; and resource life will therefore decrease. Based on temperatures required at Barrow, Kiana, Nome, and Wrangell, resource life calculations have been made for site-specific initial rock tempera- tures, TRocKk’ The procedure used to treat resource life is based on the analysis developed by Bodvarsson (Geothermtcs, September 1974). The values of thermal conductivity, density, and heat capacity of the various rock groups considered vary somewhat. However, the variations in the physical constants are slight and will have a small effect on life. We have chosen values for density, conductivity, and specific heat of the metamorphic rocks which are constant for all four sites and are approximately in the middle of the range of site-specific values. The amount of power which can be extracted from a hot, dry-rock source is a strong function of flowrate and, to a lesser degree, AT. Because of local load requirements and local thermal gradient, flowrate and AT are highly site-specific. Care should be taken in extrapolating resource life for these sites to some other, or generalized, site. Because of the economics of drilling in Alaska, we have selected values of AT at the wellhead which minimize the total number of wells required for each site. The obvious penalty which we pay for minimizing wells is that the wells must be deeper to intercept the gradient at a satisfactory temperature. Initial wellhead temperature at Barrow, Nome, and Wrangell is 250°F. Initial wellhead temperature at Kiana is 200°F. Consequently, a drop in wellhead AT at Kiana to 90 percent of its ini- tial value can be sustained over the life of the facility without de- graded performance. A drop in wellhead AT to 70 percent of its initial value can be sustained at the other three sites. We should point out a notation convention which is valid for this appendix only: A " o > TRocK, INITIAL ~ TREINJECT, INITIAL and T + T(x ,0,t) Tl ROCK FACE AT TIME t “REINJECT AT TIME t > so that our expressions for T are really descriptions of a temperature difference. Then, T r(t) = 22%) os ore os fo} is a non-dimensional description of rock-face temperature as a function of time and flow rate, where 8 = Me ova = St 2 | I . Q= Sri Total mass of water per ft” evaluated over the operating time of the facility. Btu o =1.0 Lom °F = heat capacity for water. Typical properties of the rock groups we consider are: a Btu also : ° k = 1.69 br fp °F (7 millicalories/cm°C sec) o = 166.73 oa (2.67 grams/cm*) ft Btu Cal = 2 ___—_ ir c 0.225 Lom °F (0.225 Gram? B-2 Subst 2 2 ||| S| 0. 0880 /£=— |||||\Ko20236 | Se) pe hr sec ituting 3 = 7.967 — 2 Wr: ft" (hr] In the cases of Barrow, Nome, and Wrangell, if AT drops 30 percent, the equipment which we have modeled will operate satisfactorily. Note = ° Tock, INITIAL Gata = ° = || os ° TREINJECT, INITIAL 140°F => T) 250 140 1107), In the case of Kiana, AT is allowed to drop 10 percent. = ° TRocx,nrTraL ~ 200°F = s 7 Taernsect,inttrat ~ 140°F => T, = 200° - 140° = 60°. that although initial rock temperature varies from site to site, in all cases reinjection temperature is maintained at 140°F over the life of the facility. 140°F is selected for heat-exchanger-performance purposes; i.e., circulating water in the distribution system is not allowed to drop below 122°F (50°C), because we consider temperatures below 50°C to be of marginal utility for district heating. We have no data that indicate a somewhat lower reinject temperature would cause system operation prob- lems. For Barrow, Nome, and Wrangell, T r(LIFETIME) = —# a = 0-8 || iT Ll ceeremay eee il 10, For Kiana, T ° t(LIFETIME) = =0.9 =T (x,0,LIFETIME) 7 >“ F- The steady-state (seasonally adjusted) load for each site is Annual Heating Degree Days * (12) (Maximum Monthly HDD) 20265 (12) (2486) 17500 (12) (2300) 14325 (12) (2015) __8503___ (12) (1142) estimated as follows: Max Load (MW) = Average Load (MW) Barrow 14.26 Kiana 0.89 Nome 9.72 Wrangell 4.96 For Barrow, Nome, and Wrangell, the average AT over 30 yr is 110 +77 _ ; orc S = 93.5°F . For Kiana, 60 + 54 : ly 57°F . Btu o = 1.0 TOF - Since 14.26 MW = 4.87 x 107 Bee hr 9.72 Mw = 3.32 x 10” Btw 7 r hr ” 4.96 MW = 1.69 x 107 Btu hr 0.89 MW = 3.04 x 10° Btu | hr Our initial equation for r(t) is an expression in terms of operating time and the integral of flow per unit surface area of fissure with re- spect to time. We arbitrarily choose an operating lifetime of 30 yr for our system. Our expression then determines a unique Q - Choosing a lifetime thus limits the total flow which can be passed over the fissure surface. For Barrow, Nome, and Wrangell, 7.967¥ 262980 0.7 = erf [ 1; where t = 30 yr = 262980 hr Ouax rf (Ape t) => ay = 5-574 * 10? Ln MAX ft? For Kiana, 0.9 = ert Pete zeeeee => ay = 3-504 x 107 = MAX ft Assuming that well entrance and exit effects are negligible and that flow is evenly distributed through the fracture, is a useful Qax parameter. For a fissure of half surface A', flow will be distributed over some effective fraction of the area, say, \, which is a parameter based on crack geometry, inlet and outlet flow geometry, and the resultant horizontal and vertical components of fluid velocity which determine the flow profile through the fissure. .A' then represents an effective crack area which we will call A. For the purposes of this study, we select a value of A which is equal to 9.6211 x 10° fe’. This area corresponds to a single circular crack 3500 ft in diameter with flow distributed evenly over its entire surface. In reality, the crack geometry which would yield this effective area may be two or more smaller parallel crack surfaces propagated from a common slant-drilled hole, each communicating with a second slant-drilled hole. Assuming one crack of surface A per wellset (one injection well and one extraction well), we can then determine the number of wellsets required for each site. B-5 The mass flow rate into the hydrofracted region is he= Load oT ay 4.87 x10" 5 a, 493 Lom for Barr 93.5 . hr ow 3.04 x 10° 4 Lbm = = 5.33 x 10 — for Kiana, 57 hr = 3:32 x 107 ©, 5.) 495 Lom for Nome 93.5 . hr > = 1.69 x 107 = 1.81 x 10° 2™ gor we ell 93.5 : hr cael Over 30 yr, the accumulated flow is 1.37 x 1o++ Lbm for Barrow, 1.40 x 10%? Lbm for Kiana, 9.34 x 101° Lbm for Nome, 4.76 x 101° Lbm for Wrangell. If crack area is 9.6211 x 10° ft’, then 11 = 1237 = 10 Lhe = 1.42 x 10° Lbm for Barrow; REQ'D 9.62 x 10° ft? ft? Q similarly, Qaegtp = 1-46 x 10? LB™ for Kiana, ft = 9.71 x 10 = for Nome, ft 4.95 x 10° => for Wrangell. ft B-6 The Q available from one set of wells is: MAX 5.574 x 10° = for Barrow, Nome, and Wrangell ft and 3.504 x 10° a8 for Kiana. ft Qaro! ¥- Z — is then the number of wellsets required for MAX each site; for Barrow ¥ = 2.55 => 3 wellsets, Kiana te = 0.42 => 1 wellset, Nome ty = 1.74 => 2 wellsets, Wrangell wy = 0.89 => 1 wellset. Appendix C CONSTRUCTION COSTS BASE-CASE COST ESTIMATES Base-case costs are developed in four categories: research and development (RDC), production (PC), initial development (IDC), and recurring (RC). The first three categories comprise all capital costs, while recurring costs include only those operations and maintenance activities performed after a system (or portion thereof) is producing revenue. Research and Development Cost (RDC) Costs in this category typically include the time required for administrative personnel to apply for drilling permits and for a drill- ing specialist and geologist to select drilling sites in or near the town. All base labor rates in this category are estimated at $200/day. Production Cost (PC) Drilling and Well Preparation--calculated as follows: Calculated Well Depth WU . Estimated Drilling Distance/Day * =Stimated Daily Cost ($50,000) All three figures are composite estimates based on interviews with Alaska drilling firms, the Alaska State Geological Society, and relevant well logs. Mobilization, Rig Relocation--composite estimates from the sources listed above. Loss and Repair--l percent of estimated drilling costs. Wellhead, Utilidor, and Distribution System--calculated from the bills of labor and materials detailed earlier. Initial Development Cost (IDC) System Start-Up--training costs are based on an operations and maintenance crew of three men per well pair. Crew members are costed c-1 at $10/hr, supervisors at $15/hr. Technical data is expected to comprise 250 pages of material, at a preparation cost of $20/page. Installation-Checkout--Initial spares stockage is estimated at 3 per- cent of combined wellhead and distribution system material cost. Labor includes all crew costs (devoted to on-the-job training and checkout) subsequent to training and prior to on-line operation. Demobilization--the cost of shipping the well rig back to its point of origin. Compiled from estimates from the sources referenced under Drilling and Well Preparation. Recurring Cost (RC) Spares Inventory Replenishment is estimated as 10 percent of initial spares stockage, per year. Labor is based on the crew composition and costs discussed under System Start-Up above. * * * Costs subsequent to the initial year are assumed to inflate at a 6-percent annual rate. BASE-CASE FINANCIAL SUMMARY The summary table data are calculated as follows: Total Capital Investment--RDC + PC + IDC 30-Yr Ownership Cost--Interest Rate (10%) x System Lifetime x Total Capital Investment Average Annual Ownership Cost-- Seat “Us cost Average Annual Cost--Based on setting, revenues equal to costs: (30-Yr Ownership Cost + RC)-(Royalties - 10%)-(Taxes - 2.25%) 30 C-2 Installation Costs: Direct Materials Direct Labor Utilidor or Trench Piping Installation Freight Total OQ 2 Barrow Huslia Kiana Nikolski Nome Wrangell $2,009,400 $262,008 $294,088 $ 94,036 $1,579,140 $1,312,786 1,003,295 197,918 213,158 65,295 964,012 825,235 1,520,120 23,100 224,640 8,000 1,274,700 40,000 187,478 25,636 26,163 13,717 158,652 72,521 $4,720,293 $508 , 662 $758,049 $181,048 $3,976,504 $2,250,542 9-9 Invitation No. i Date 1 CONSTRUCTION COST ESTIMATE “—— PROJECT Barrow Geothermal Installation (CU cove a Cicove c prorne me stimotor cher LOCATION Barrow, Alaska cove B_ [ ]coveE 0 QUANTITY MATERIAL LABOR TOTAL FREIGHT DISTRIBUTION SYSTEM EQUIPMENT Unit Total ola No.Units | Unit | Price Cost Hrs. Mat'l & Lobor wt lbs dia. Fiberglass/epoxy and foam 5M 1,150 | ea. [$343 [$394,450 |4.66 {5,359 115,000 polyurethane insulation 8" sleeves including Jacket 1,150 | ea. | 9.75] 11,210 265 5,750 2" dia. ate dene as nominal polyurethane tacatatt n 3,120 | ea. 125 . 390,000 124,800 3,120 ea. 8.50] 26,520 15,600 “Tee connection, F/F, 2"x2 with 2" polyurethane insula= | tion 178 ea. ea. ea. 34.00] 6,050 34.00 270 60.00 | 60,000 6 6,000 ee connection, F/E, 8™x8"x “with 2" pelyurethane—ineula— > tion — 4h f Tee connection, F f, SxB"x with 2" polyurethane_insula= tion “Reducer, —F/E,—2"xt"wtth-2"* olyurethane insulation 16 ea. 16 ea. tf | 450 ea. 280.00 4,480 B20.80| 5,130 40.80] 18,360 -$-— 4 -— +e. + | FE 240 | 17 272 2 900 $-9 Invitation No. iDate 2 pneumatie- operater—w/positiornee -— if. t CONSTRUCTION COST ESTIMATE —- Drawing No. PROJECT Barrow Geothermal Installation (-)covE a (J cove c LOCATION Barrow, Alaska _ cooe Bf }cove 0 | QUANTITY MATERIAL 1 LABOR Unit Hrs Total BAAceE <P aioe No. Units | Unit Price Cost Hrs. Rote Cost ucer i. x with £ , F/E, 8 2 0.09 $4,800 . Sparechen culdtion 16 ea. $30 $ 5.31 85 ubeerFTy valves 2" 75" FuIT | 7 63 | 4,032 | 1.70 | 109 lug, rubber lined, al /br dise. | ea. ,— =o nanual operators ! | Drain valves I", bronze gate, | T handuheel operator 64 | ea. | =} 896 .50] 32 I Flanges — 12 ull bole { ana ot |. | | 2 0.801102 | | pattern = 2'' (EF) |_128 EBs ” 4535 7 4 anges ys" | I paccern = ge) (ut bole | 6 | ea. | 129 | 2,064 | 3.10 | 50 “WELLNEAD EQUIPMENT 1 | | | Th | ~~ ee ho 4 ees oe cape Tae lh gence a ““Tominal Carbon steél pipe, fo! 0.56 | 168 6=B sch 80 tnd 300 fe $7. 75 $ 2, 325 |‘ 5 8,700 prepared for butt weld connec on —--——- = m™ ON? 3 0 — = cold ond nreeenegute 80, butt’ “28 | ea [41.16] 1,152 ha 343 896 6" 1500# Flange, raised Face, ~ a ch — weld_ neck, schedule 80 hore ea 206” 13,6%6 §. “3h | 406 — 164 7,872 6" '900/ wanitially operated gate " i valve, BW_end connections ea 13,677] 44,124 [16.00 | 192 655 | 7,860 4" pressure control valve 7 TT al - 3 9,000} 27,000 24.00} 72 700 {2,100 —+ —+ 9-9 Inviiation No. i i Date 3 Sn. of __ CONSTRUCTION COST ESTIMATE Drawing No. PROJECT Barrow Geothermal Installation (-Jcooe a ([Jcone c LocaTION __—sBarrow, Alaska ; (Jeooe e [-]cone 0 QUANTITY MATERIAL LABOR ee Hrs Total No. Units | Unit Cost __ [heen |e Rote nstrumentation, control panel, ono 697 anh instr. tai > 3 ea $7, 000 $21,000 |35.00 105 ectrical switchgear, relay rack,_& misc. wiring Centrifugal brine reinjection} Pump _ Wellset pressurizing pump 3 ea Heat exchanger--shell & tube 9 [ea 5,000 | 675,000 240.01 2,16 Weatherproof insulated box housing ——____ Circulating water pump- distribution-system ~— oe -~ — ah + pee 602,824 oe — |__| 602,8 @47.67 @ | 0.311 —— _ {842,67 | fn | $1,003, 295 | __ | _ $187,478 oe ASIC SYSTEM TOTAL, $3,200,173 | $1,520,120 _ . t ‘| 7 TOTAL $4,720,293°~ a L SS Fj a a ee | tt Surface Utilidor-containing r & 2" insulated distr £-9 Invitatiaa ..0. |Vate 1 Snt._—__ of CONSTRUCTION COST ESTIMATE Drawing No. PROJECT Huslia Geothermal Installation (-] cove a (-) cove c = a [Checker Location luslia, Alaska (“cone a__{“)cone 0 | QUANTITY MATERIAL LAgor TOTAL FREIGHT DISTRIBUTION SYSTEM EQUIPMEN' Unit Hrs Total , _ sasat t No Units | Unit Price | Cost |. nit | Hes. | Rate | Cost Mat! & Labor " a5 — Oe a Tiberg O” andenethane {| 1050 | ea |$153 $160,650 | 2.24 | 2,35 48,300 insulation sleeves-3" including jacket and foam 1050 | ea 9.75] 10,238 | 0.11 | 116 ree connections, f/e, x3"x th 2" 65 |ea | 82 5,330 | 4-56 296 peducer "xt" 7e, with 2 50 | ea |98.40| 4,920 ps 78 — connection fittingh, 12 | ea 82 984 2.32 28 butterfly valves—-3" 125% full ug rubber lined_al/br disc, 20 | ea [89.70] 1,794 | 2.35 | 47 nanual operator ~ | | train valve-I" bronze gate | | > 0. anda or 21 ea 14 294 50} 11 — = Fy, ult Bort 40 | ea 34 1,360 }1.15 1) 46 | | “WELLHEAD EQUTPHENT f i “| 7 ‘“nommal carbon steel pipe, | | 106-B, standard schedule, 100 ft 7.75 775 re 56 ‘nds prepared for std butt veld connection t { t ne cqaca = | | or 90" eT, standard schedule yy Vea [a1.16] —412—«412. 26} 123 Flanged connection. Invilathon No. | Dots 2 ; it CONSTRUCTION COST ESTIMATE | ou ; a itt. ——|Orowing No ~ a PROJECT Huslia Geothermal Installation C) CODE A C) cope c — oo 7 Estimator ————t—~— Re SSS wocation ___sHuslia, Alaska _ _____I{- cove e [Vconr » | — | QUANTITY MATERIAL LABOR “TOTAL __ FREIGHT i fire Total ~ + . oe W Fotol - _ _ _ No Units | Unit eit Hes. Rote — Cost Matt &@ Ughor EG pa 6" 125# Flange, raised Face, 16 2 25 |. 36 164 11 2 626 jweld neck,.std.schedule— {£8 ; | pe fe"-1509 manually operated gate] — Heelontt oT I ~ == 5. 25 21 valve,- £langed—end-connect ional = et ————— 4. ——— es ag 7 |__788 4"temperature control globe ~ ~T- TD. 9 900 ‘+112. 601 ‘12 —T nn valve, pneumatic_ operator___'__! __ on | 7200 —j4 200 10° ek a a qo == _— | oo ——}— seo bai Hos ~ fp Instrumentation, control panelf, 1 =f 000 8,000 140. 00 | 40 400 t 400 instrument_air compressor + —— — —-— at 7 = — _ ae | 1 Electrical switchgear, relay 1 | Lot |9,000] 9,000 (45. 00| 45 300 | 300 rack, & misc, wiring. = = fof fe = el J ee - ae ———— fj} _—____ di eee Centrifugal wellhead brine | ea | 500 | 500 | 8.00! 8 : 1150! 150 \reinjection pump — [ef Af ae a | | ' Wellhea pressure control fa ene iat ee i = oe ~t a valve a/pbsitimer ea_|1, 2500] 1,500 | 0.00; 10 vet | 200 200 j \ | : — - Heat exchanger--plate type--125# 1 L iea 9,800 | 9,800 '36.00! 36 i ! \ il, 350° 1,350 se es eee a+ pS oe et Circulating water pump- i : | distribution-system-—-—- = es —-_ nen 150 | 130, a anand | a, | + -___- iWeatherproot insulated box | 1 ‘ 15,000! 5,000 jhousing. -.—--~-----—-—-_--__- -- 1 - nn pe ft - = — $69, 286 | yo COU + ~ —— ee _— : i CONSTRUCTION COST ESTIMATE Invitation No. j Date : 3 Snt._—__ of Drowing No. PROJECT Huslia Geothermal Installation (CJcove a (-)copve c Esilmator cker cooe 8 [ ]cove 0 | LOCATION luslia, Alaska 7 TT QUANTITY MATERIAL LABOR FREIGHT Ualt \Total otal Er No Units | Unit Price Cost Hrs. | Rate wt Carried Forward | $238,189 3,389 $69 , 286 | Loss Add 10% 23,819 @ {58.40 $25,636 $485,562 Excavate trench for two 3” insulated—pipes—2'=0" to. 3'-0" deep 10,500 OT-9 Kiana Geothermal Insta Location Kiana, Alaska PROJECT QUANTITY CONSTRUCTION GOST ESTIMATE Invitation No. DISTRIBUTION SYSTEM EQUIPMENT 7 tibergTass/epoxy irethane insulation No. Units | Unit ly= 720 ea. Cost eves — 3" including jacket d_ foam inl ea. 7,020 IT, FibergT : wt “i 2H Headed 80 | ea. 4,160 insulation onnections, F/E, 3°x ith 2" 1 ir 202 il 16,564 T= 3"xT F7E, with 2° ~ i h 1 i 180 ea. 17,712 urterfly valves — 3" 125i | 46 uw full lug, rubber lined _al/bhr 4 E 1,435 isc, manual operators | | ain valves —- I" bronze gate, | i a 8 ea 112 eral connection Fitting | 3" 3" 4" 16 poe 1,312 : = ft a Flanges ~ 125" FF, full bolt | | = 3" { 32 iT 1,088 | | | ee TT-9 CONSTRUCTION COST ESTIMATE Invitation No. PROJECT Kiana Geothermal Installation (C) cove a () cove c LOCATION Kiana, Alaska cove 8 [ cone 0 QUANTITY ' MATERIAL LABOR WELLHEAD EQUIPMENT . Unit Total +—nomtiat— No. Units | Unit Price Cost Hrs. | Rate chedule 80 100 ft $7.75 775 56 prepared for butt weld connec 6" 90° ell, schedule 80, butt wold_en 10 ea }41.16 412 123 6" 1500F Flange, ralsed Face weld k,_scl le 80 16 ea 288 4,608 136 6° 900# manually operated gat val Bu 1 4 ea 3,677 | 14,708 64 4" pressure control valve | Samar is nee ) 1 ea [9,000] 9,000 24 | Instrumentation, control pane], 1 ea 12,000] 12,000 60 instrument _air_compressor | Electrical switchgear, relay “| ] rack-& mise,wiring—- 7 {tot 2000 | __9,000 oe = Centrifugal wellhead brine 1 ea 680 680 12.00! 12 mp } - _ js T Wellset pressurizing pump 1 ea , 895 1,895 ]35.00! 35 ee _ tT | ! [ Heat exchanger--shell & tube 1 [ea 9,780} 39,780 icoled 160 tT | Weatherproof Insulated box —|~ Sj at . 0 housing 8" _x_20' 1__|ea__ [14,300] 14,300 20 | 2 tI-0 Invitation No. | Date 3 Snt._—_ of CONSTRUCTION COST ESTIMATE : - Drawing No. PROJECT | Kiana Geothermal Installation (C)cove a C) cove c stimoator cher LOCATION _ Kiana, Alaska cove 8 [ ]cone 0 QUANTITY MATERIAL LABOR Unit Total No Units | Unit | Price Cost Hrs. Circulating water pump-distri- bution system 20 ea $758,049 €T-9 CONSTRUCTION COST ESTIMATE PROJECT Nikolski Geothermal Installation Invitation No. i Date sn. Drawing No. (-Jcooe a [_]cove c LOCATION. Nikolski, Alaska QUANTITY MATERIAL DISTRIBUTION SYSTEM rare ; Unit i No. Units | Unit Price Cost Cost Mat'l & Labor dia. Fiberglass/epoxy ll 200 | ea. | $125 | $25,000 40 1b} 8,000 0 ft Llength— eeves — 2 including ‘ional pede alam 200 ea. 8.50 1,700 + 1 ell Fiberglass/epoxy + 2x2" with 2" polyurethane insulation 34.00 204 Tee connections — Dae IgM IU GUIU/ aut ley 74 | ea. |60.00| 4,440 tion | ‘Reducer = 2"xI" F/E with 2” 60 polyurethane—insulation _ ©4- 140.80] 2,448 Butterfly valves 2", I25# Ful} | lug,—rubber_lined, al/br discy 10 ea-.| 63 630 ; 1701 manual operators | | a { 7 + {= — Drain valves — I", bronzé gatd + | 1 | r +handwheel operator ! 40 ase | | 14 140 _| 0:50! 5 C 3 | 23 . | “Ftanges-=—125# fut bolt 20 il TE T rt pattern_2" (FF) i Petey in NOM Ge AUS AE 4 80 45° Tateral connection Ni, i iM fi Tl iy NiTTT ;fiteing = 2" x 2" x 2" 3 i eee ee eee Le | | | sili la2 TTT : | + +--+ TTT i ! ; | | iin t 0H) 7 r +t + 4 ' | TE A A TT YT-9 —L_ of Invitation No. | Date eye _ CONSTRUCTION COST ESTIMATE : Ti Drawing No. | i) PROJECT ____—s Nikolski Geothermal Installatior [-)cove a (J) cove c a LOCATION ss Nikolski, Alaska __ cooe 8 [ ]cope 0 wD MATERIAL QUANTITY LABOR WELLHEAD EQUIPMENT Unit Total fominal-carbon-steel pipe No Units | Unit Price Cost Hrs. Cost ominal carbon § Pip Al06=-B, std. schedule. End pke-100 ft 7.75 |$ 775 _56 pared for butt weld faite 6" 90° ell standard schedule | 10 ea |41.16 412 |12.26 | 123 6" I2Z5# flange, raised Face, | Ty weld neck standard schedule ic Federe id ec ee elen 36 6" 150#-manuatty—operated- ; = i 7 26 1,052 Valve. Flanged_end connec- Lt ? hs : 04 13 tions PELE I 4 Mt 4" temperature control valve, Whilha " L diaphragm operator pre ill We eee 2,200 12 anil Tnstrumentation, control pane{, 1 ea 8,000 8,000 | 40 instrument air compressor. __j "| © | { Le | | EL a ans GR a om Electrical switchgear, relay | 1 ay 9,000 Ls doll 45 rack, misc.—wiring——__ - {oo — eS =I | Centrifugal wellhead brine} ~~ Was SUPT SaSIINIIE wr bi TIT Leinjection_pump Pt r : + i Downhole booster pump 3,000 ho.00 ' 20 ae Be ale 0 anit a BEE REAL Senne ase manele _ ut {Heat exchan 6,000 [4 24 a i culating water pump=— it 7 tye distribution system er Tae I:ESSAP UEC ee mi Invitation No. | Date 3 / CONSTRUCTION COST ESTIMATE =— PROJECT Nikolski Geothermal Installation (cove a C)cove c Drawing Na. ~~ silmoator pecker LOCATION Nikolski, Alaska CODE 8 (-) cope o re QUANTITY MATERIAL LABOR FREIGHT No Units | Unit pie Cc we _ ° s ni c. i Cost Weatherproof Insulated box : ‘ m es —_ : housing 1 ea 14,300) $14, 300 5000 1b 5,000 85,487 23,980 ee Add Ldss_ 10% 8,549 @ 0.572 $94 ,036 $65,295 $13,717 Excavate trench for 2" dta. Ainsulated_pipe 2'=-0" to 3'-0" deep 2,000} LF TOTAL 8,000 $181,048 oo + -+— tt —- 9T-9 Invitation No. | Date 11 ot CONSTRUCTION COST ESTIMATE “—? Drawing No. PROJECT Nome Geothermal Installation (-)cove a Cl) cove c ‘siimator : LOCATION Nome, Alaska cove. 8 [ ]cone o | QUANTITY MATERIAL i LABOR TOTAL DISTRIBUTION SYSTEM EQUIPMEN Total ; No. Units | Unit Cost Hrs. | Rate Cost Mat'l & Lobor dia. fiberglass /epoxy 1,000 | ea. | $241 6241,000 | 4.42]4,420 78 1b] 78,000 polyurethane insulation Sleeves - 6" including jacket !7 000] ea. 8,500 0.22] 220 5,000 eat 2" dia. fiberglass/epoxy 3,200] ea. 400,000 6,528 128,000 speels Qu > > . polyurethane insulation —— 2™ Including Jacke 3,200] ea. 27,200 = 320 16, 000 90° ells, F7/E 6" x 6" w t -polyurethane- insulation = — $4870 5.26 | 158 “90° ells, F/E 2" x 2” wit “| _polyurethane_insulati | 120 ea. 4080 12546 | 271 | | | _ + +— ' 42 ea. 408 12.22 | 27 | + _ + | +. | a » 2x2"x277 300 | ea. 78,000 | 3.42 '4,446 4 + + — — | | ! i [ 1,200 ea. 48,960 i .85 ; 1,020 pa t ' i y valves 6", 125 fu + —- ' | 12 . 4.10 ; 49 lug,—rubber_lined, al/br disc | a $4390) manual operators | LT-9 CONSTRUCTION COST ESTIMATE PROJECT Nome Geothermal Installation Invitation No. (C)coo—e a= [-) cove c Date Drawing No. stimator LOCATION Nome, Alaska cope 8 _ [ ]cove o QUANTITY MATERIAL i LABOR Ualt c Totat i c No. Units | Unit rice ost cs. ate ost utterfly valves 2°, 125 Fa lined, al/br di 128 ea. | $63 $8,064 1.70} 218 manual operators Drain valves I", bronze gate - > 7 . 1 1,792 | handwheel operator + _ 4 ? 0.50] 64 ele 24 ea. | 129 | 3,096 54 Flanges 1254+ 2" (PR) 256 ea. | 34 8,704 of WELLHEAD EQUIPMENT | 6" nominal carbon steel pipe { A106-B, schedule 80, Ends? rq- 200 | fe 7.75 | 1,550 0.56] 112 pared tor butt weld connect on — - + +——+ [ t 6"-90°-e1T, schedule-80;buET 4 ; weld end prep ___ 20 ea 41.16 . 823 12.26] 245 6 1500# FIange, raised face, | T : : 8 bal apg T {weld neck, schedule 80 bore 32 ea | 288 9,216 : | | [ 6" 900% manually operated gate} {- : 6 001 128 | E valve, BW end connections +8 . | Lil 29,416 | ’ ; _ [ {4 pressure control valve im ' lonaumatric operator wast 2 | ea _|9,000| 18,000 (24:00, 48 positfoner ' { : | T |Tastrumentation, control panel| ._ Yo 7 t, + | i Reateuaent Mit cpupueseor 2 | ea {7,000 | 14,000 aL | LOCATION _ Nome, Alaska Invitation No. |Dote 3 CONSTRUCTION COST ESTIMATE irene J) N Geott 1 Installation T il ik Teas ami ) PROJECT ss“ Nome Geothermal Insta c (Jcove a [cove c cinaenr om Ckeckers ——-— JON | ae a CODE 8B {"\cone_o i] QUANTITY MATERIAL LABOR Unit H Total jar WissteisaY eotechaese=-xe1 No. Units | Unit Price Cost [cen] "ste Electrical switchgear, relay ck, -&-misc.—wiring |} 10,90 : PLO, Goo 10.00 | ae aaae a a _ is Centrifugal wellhead brine 2 680 1, 360 |i 00 +reinjectien—pump— — + _ | { Se pt { — 4 Heat exchanger-~shell & tube 6 75 , 00! 450,000 |240.04 — aan 7 | 2 — | ‘a 2 1,895 35.00 Wellset pressurizing pump ‘Weatherproof insulated box |_ oT, 9 housing—_.— 4 2 14,30 ) {20.00 5, 000 20, 000 a ° Circulating water pump-— | ° —- distribution_system 1 ea_|4,163 20.00) _ 2 1,263] 1,263 | 20,55 —————— —_____ — + Misha di had Lods 10% 0.343 =. — — — -4 + 7 —+ —<—<—< $1,579,140: | 158,652 RaneeneeD = — t 4 —— mn + . a aie L. —f ————{_. ee |. BA TC sysiTEM TOTAL ig9 701 804, en -— - | — ~-- =f ite ———— syttace. utilidor==containii - rt 6" or 2" insulated pipe re 42,000] LF || @f30.35 | ! ieee a Ea . = t 1 et + ct Invitation No. | Date snl ot CONSTRUCTION COST ESTIMATE Drawing No. PROJECT Wrangell Geothermal Installation (cove c a . sar LOCATION Wrangell, Alaska [| cone o OTe MATERIAL LABOR DISTRIBUTION SYSTEM EQUIPMENT — Dalt Total in . No. Units | Unit Price Cost Hrs. | Rate Cost Mat! & Lobor Ss 6 bem tt ner EINES EPORY [2,000 ea. [3241 [$482,000 | 4.42 | 8,84 78 1b] 156,000 po te schans insu fatton —— Yncluding jacket [ and foam. 2,000 ea. 8.50} 17,000 440 10,000 90° ells, F/E, 6"x6" with 2" 6 polyurethane insulation 4 : nS ai = At : 45° ells, F/R, 6"x6" with 2" r 2 7.8 | 140 ° i ation 18 ea. {129.0 2,322 130 . Aa oO @é connections, F/E, eee 12 9,480 Ce tpenetnead’tnautac 790 ea. 192.00] 151,680 7,50 (15,925 2 tion f | | — | . - + Reducers, F/E, 6"xKI™ with 2” | (yaar hang=inentallicn | 760 t* 230.40] 175,104 4.00 {3,040 | 4 | 3,040 | . t \ | {: saitterfly valves—6" 125° full | | : . . 4.10 2 hae, Srey tines. sla disc, ; 20 |ea- [199.2 5,976 14.10 | 123 | | 48 | 1,440 nanual operator = t + _ i mi [4 fain valves-I", bronze gate | r Tt m va =1", . ‘ fees oeraese + . - | 14 B26 70h = = + p23 | | | pranges; 125’ Full bolt pate 1 "CEE. ulT Holt pa en 60 et 129 7,740 [a2 135 t 17.8 | 468 ' ; 1 _ 4 { : 4 ase 7 : | 45° lateral connection fittin 10 i ea. |12 1,290 5. 20 | 52 7.8 | 78 I ico — | fie ) 0z-9 | _______ CONSTRUCTION COST ESTIMATE Invitation No. | Dote Drawing Wo. PROJECT Wrangell Geothermal Installation CODE A (\ cone c ee 7 i sifmator Checkar Location Wrangell, Alaska = If )cove e _[“]cove 0 —= | guantity MATERIAL LABOR FREIGHT WELLHEAD EQUIPMENT | Sait — Weg 7 VF aa feta a ee or INo Units | Unit Price | Cost eri eit’; Hrs [Rote | Cost po} wa /6" nominal carbon steel pipe, 7 41 ib A106-B, schedule_80.Eads 200 | ft [$7.75]$ 1,550 | 0.56] 112 | en {2800 prepared for butt weld connec | -tion—— —-—- — 1 -—— ST —}-———-+- - f-- 7 ! 1-gn° on ~~ 4-4 ff —~----. — bu 90" ell, schedule 80, butt’: 41.16 823 |12.26' 245 | 32 | 640 ee to —— — ls aioe 6" 1500# flange, raised face, + Lo ja oie jlo ce salt _ brace ht weld neck,..schedule 80 bore _ af == et =e = 9,216 as a pee —— f $GeenscpeiRea i (SIC DS ES SOEUR ust 4. 5, 248 | ge 9001 ally operated gat i ff vi Sar ees meine Goes = manua y operated ga i ee “fs epee 29,416 sean | 655 Js, 240 \ 1. \ | 4" pressure control valve, ~ foo fo | N00 tao oe ee 7 70 400 jrosttione operator _ te = 7 i 24. 00. 4B Ene i a - oe 0 ‘1, - positioner i i i i oe ef aoe ee Re a fe te me 1 ' L | | | Instrumentation, control panel, . 5.00" 70 SS See instrument..air compressor —. 2. -{ ~ 235.00 at a 500. : 1,000 5 1 ! —-—1 =n “a0)- bn Gor teal L ee ee eee =p Electrical ere pein relay | , : : : jrack, & misc. wiring _ : et yt. a _ {f9+007 60) aa eae : 400° i 400 | a a | 2 | A 680 1,360 Tn. 00 24 250 yr 500 ! | | lWellset pressurizing pump 2 | 1,895 pt 2 -ea_|1,895| 3,790 35.00. 70° eesti ches eee i ! \ T i ‘ea (66,50 199, ,500 oo. 00 600 Heat exchanger—-shell & tube | 3 | ae eee { Se ee ee eens Caneel e J | _ Ss T@-9 witation No. , Date Snt. 2 of | CONSTRUCTION COST ESTIMATE . a . 7 7 = Brewing WS. — PROJECT Wrangell Geothermal Installation (-) cone a (cove c oe ~ . TE stIimotor [Checker LOCATION _ Wrangell, Alaska . cooe e { lcooe o | | - QUANTITY MATERIAL LABOR TOTAL FREIGHT i, Unit Hrs Total 7 , ea ~ Total No. Units | Unit Price | Cost eit | Hrs Rote Cost Mall & Lobar “Voit Wt waatherproor insulated box “housing —— 4 ea {14,304 $57,200 ae 80 5,000]1b 20,000 | iisttibaticn aysten | 2,321 20.00 20 - | 800 | 800° ; $1,193,442 20,45 | 302,171 oe = + —— — anne Ji 7 — = oo ee 119,344] | @ [40.34 @_ 0.24 aiatz_ peel $825,235 | 72,521 pn = See ! bast SYSTEM TOTAL _ Excavate trench for 6" for 2 insulated pipes, _2'-0" to _ 3'-0" deep 20,000 a 9 ere fn a feces we ee a + _--—--——---4--— +} ' | Barrow Apprentice or Foreman Plumber Laborer Rate: 21.23 19.77 14.83 70 hrs 1,486.10 1,383.90 1,038.10 Subsistence $50 x 7 350.00 350.00 350.00 1,836.10 1,733.90 1,388.10 + 50 + 50 + 50 36.72 34.68 27.76 ae x 2 <i 36.72 69.36 27.76 Average Rate $33.45 (Allow 6-wk tour) = 6 x 50 or 300 hr Flight: 218.06 Travel Time: 8 hr x 2 = 16 Contingency = 2 18 hr @ 18.90 = 340.20 $558.26 + 300 $1.86 $35.31 Add Contractors insurances, bonds, taxes, etc. 35% $12.36 Hourly Rate $47.67 C-22 Huslia Rate: 70 br Subsistence $50 x 7 Foreman 21.23 1,486.10 350.00 1,836.10 + 50 36.72 None (Allow 4-wk tour) 200 hr Flight: Plumber 19.77 1,383.90 350.00 1,733.90 34.68 69.36 Travel time 8 hr x 3 = 24 hr @ 18.90 Waiting time 8 hr Add contractors insurance, bonds, taxes, etc. (3 men) 6 days = 48 hr @ 32.37 Apprentice or Laborer 14.83 1,038.10 350.00 1,388.10 + 50 27.76 x 1 27.76 Average Rate $32.37 171.14 453.60 1,553.76 2,178.50 +_200 $10.89 $43.26 35% $15.14 Hourly Rate $58.40 Kiana Apprentice or Foreman Plumber Laborer Rate: 21.23 19.77 14.83 70 hr 1,486.10 1,383.90 1,038.10 Subsistence $50 x 7 350.00 350.00 350.00 1,836.10 1,733.90 1,388.10 + 50 + 50 +_50 36.72 34.68 27.76 None 2 1 69.36 27.76 Average Rate $32.37 (Allow 4-wk tour) 200 hr Flight: 234.72 Travel time 8 hr x 3 = 24 hr @ 18.90 453.60 Waiting time 8 hr (3 men) 3 days = 24 @ 33.37 800.88 1,489.20 +200 $ 7.45 $39.82 Add contractors insurance, bonds, taxes, etc. 35% $13.94 Hourly Rate $53.76 C-24 Nikolski Apprentice or Plumber Laborer Rate: 19.23 14.42 102 hr 1,961.46 1,470.84 Subsistence $50 x 7 350.00 350.00 2,311.46 1,820.84 + 60 + 60 38.52 30.35 Average Rate (Allow 7-wk tour) 420 hr Flight 427.72 Travel Time 8 hr x 3 = 24 @ 18.90 453.60 Waiting Time 8 hr x 6 = 48 @ 34.44 1,653.12 2,534.44 + 420 Add contractors insurance, bonds, taxes, etc. 35% Hourly Rate $34.44 Nome Rate: 70 hr Subsistence $50 x 7 Foreman 21.23 1,486.10 350.00 1,836.10 + 50 36.72 18.36 (Allow 6-wk tour) 300 hr Flight Travel Time 8 hr x 2 = Contingency = 16 2 18 hr 19.77 _ 350.00 + 50 Plumber 1,383.90 1,733.90 34.68 69.36 @ 18.90 = Add contractors insurance, bonds, etc. 35% C-26 Apprentice or Laborer 14.83 1,038.10 _ 350.00 1,388.10 + 50 27.76 mee 27.76 Average Rate 182.02 340.20 522.22 +_ 300 Hourly Rate $32.99 $1.74 $34.73 $12.16 $46.89 Wrangell Foreman Rate: 20.69 52 hr 1,075.88 Subsistence 40 x 7 280.00 1,355.88 + 44 30.82 x1 30.82 (Allow 6-wk tour) 300 hr Flight Travel Time 8 hr x 2 = Contingency = 16 2 Plumber 19.23 999.96 280.00 1,279.96 + 44 29.09 58.18 18 hr @ 18.40 = Add contractors insurance, bonds, etc. 35% Apprentice or Laborer 14.42 749.84 280.00 1,029.84 + 44 23.41 x1 23.41 Average Rate 203.50 331.20 534.70 + 300 Hourly Rate $28.10 $1.78 $29.88 $10.46 $40.34 Basic Plumber's Rate North of 63° Latitude South of 63° Latitude Barrow Wrangell Nome Nikolski Kiana Huslia Basic Rate $17.42 $16.90 Health & Welfare -60 -73 Pension 1.30 1.40 I.A.P.F. - -05 App. Tr. 45 15 Total $19.77 $19.23 Foreman + $1.46/hr Apprentice 75% of journeyman rate c-28 Working Conditions North of 63° Latitude (Barrow, Nome, Kiana, & Huslia) Normal current working week 6 days at 10 hr = 60 hr Overtime paid = 10 hr Total 70 hr paid Production Hours: 50 hr South of 63° Latitude (Wrangell; Southeast Alaska) 6 days at 8 hr = 48 hr Overtime paid = 4 hr Total 52 hr paid Production Hours: 44 hr Nikolski (Aleutian Chain) 7 days at 12 hr = 84 hr Overtime paid 28 hr Total 102 hr paid | Production Hours: 60 hr c-29 Size of Crew Barrow Nome Kiana Huslia Wrangell Nikolski Foreman Plumbers Apprentice or Foreman (part Plumbers Apprentice Plumbers Apprentice Plumbers Apprentice Foreman Plumbers Apprentice Plumber Apprentice or or or or or Laborer time) Laborer Laborer Laborer Laborer Laborer c-30 Air Fares Anchorage to: Point Barrow Nome Kiana Huslia Nikolski Wrangell Daily Daily Via Kotzebue Daily Via Galena Monday & Thursday Thursday Only Daily From Seattle Daily C=-31 $218. $182. $234. $171. $427. $203. $194. 00 02 72 14 72 50 16 return return return (overnight return (overnight return return via Juneau return via Juneau outward) outward) Transportation Barrow Barge: Handling: Nome Barge: Handling: Kiana Barge: Handling: Huslia Barge: Handling: Nikolski Barge: Flight: Handling: Wrangell Barge: Handling: 0.111/1b 0.200 0.311 0.143/1b 0.200 0.343 0.167/1b 0.200 0.367 0.170/1b 0.200 0.370 0.322/1b 0.250 0.572 trans. trans. trans. trans. trans. 0.09/1b trans. 0.15 0.24 C-32 Appendix D LOAD-SIZING CALCULATIONS FOR HUSLIA AND KIANA The load-size calculations presented below are for the town of Huslia. These calculations are very similar to the calculations for Nikolski and Wrangell, the only variations being in the materials used for construction, AT, the number and size of structures to be heated, and fuel used. Huslia Two methods are used to size the thermal load for Huslia. Method 1. The town of Huslia comprises thirty houses and one store. Each building uses approximately seven cords of wood per year for heating and cooking. For purposes of this study, we assume that virtually all the wood burned is used to heat the houses. The heating value used for wood is 16,300,000 Btu/cord. Stove efficiency is as- sumed to be 0.50. Because of Huslia's small size (pop. 159), climatologic data have not been recorded. The location nearest Huslia for which data are available is Hughes, Alaska, about 60 mi northeast of Huslia. For the years 1942 through 1967, mean daily minimum temperature for the month of December is -19.1°F. For purposes of this study, we assume an outside design temperature of -20°F. Data for Hughes indicate that 15,233 heating degree days can be expected in an average year. Aver- age heating degree days for December are 2344. Since it is expected that seasonal use of firewood is directly proportional to the fraction of annual heating degree days, fuel consumption in Huslia is estimated to be 2344 IL 7 cords 15233° “structure [ ](31 structures] = 33.4 cords used during December in a typical year. The design heat loss due to all heat-transfer mechanisms is A: An indoor temperature of 75°F at Huslia is assumed. Then, using the ASHRAE Modified Degree Day Procedure for sizing load (1976 ASHRAF Systems, p. 43.8), #, 7 EATnV D(24) CC, where E = 33.4 cords, AT =-75 - (-20) = 95°F, the difference between indoor and outdoor design temperature, n =0.5, 7 Btu cord ’ Vo = 1.63 x 10 oO u 2344 heating degree days, c = 0.57, an interim heat loss correction factor, cS = 1.36, a partial load correction factor assuming that existing wood-burning equipment is not oversized at all. Substituting: _ 5 Btu EL = 5.93 x 10 ir 5 Btu\/ 1 hr \ /17.57 watts 1 MW 5.93 10 ey (Ss) sae) = 0.174 MW ERMAL h 60 min Btu 10° watts D-2 Method 2. The second technique used to size the load for Huslia is the ASHRAE heating load general procedure (1972 ASHRAE Handbook of Fundamentals, Chap. 21). The standard ASHRAE house has been modified to reflect construction of the average Huslia house. Huslia has 30 residences. Each is a single-story log structure with a pitched roof. The houses average about 20 ft x 20 ft and are generally built on pilings leaving a dead air space between the floor and the ground. We assume that 7 percent of the exterior wall surface is occupied by windows. The one store in Huslia--a two-story building, 30 ft x 28 ft--is con- structed the same as the houses. Walls: For the houses, each wall is 20 ft x 10 ft = 200 et; of the total, 14 ee? is window area; 186 et? is log wall. For the store, each wall is approximately 29 ft x 20 ft = 580 ft’, of which 40.6 et? is window and 539.4 ft? is log wall. The log por- tion of the walls is modeled as follows: T, = outside tempera- ture = -20°F for Huslia T; = inside temperature = 75°F (os eS (9) (EE Oy The following table lists the thermal resistances for the homogeneous log wall: Location Resistance 1. Outside surface (15-mph wind assumed) 0.17 2. 6-in.-thick, squared log wall 7.85 3. Inside surface (still air) 0.68 Total Resistance 8.70 1 Btu Then, U === 0.1149 ———_ .. WALL R hr et2°F Windows: From ASHRAE, double-paned windows have Pitched Roofs (45° pitch assumed): Area of each house roof = 566 ft’; area of store roof = 1188 et? T; = 85°F (assumed) D-4 For the purpose of this heat-transfer estimate, insulation on the ceiling and the laminated roof are combined into one series of thermal resistances (see table below). Location Resistance 1. Outside surface (15-mph wind assumed) 0.17 2. Asphalt shingle roofing 0.44 3. Building paper 0.06 4. Plywood deck, 5/8-in. 0.80 5. R-9 insulation 9.00 6. Gypsum wallboard, 1/2-in. 0.45 7. Inside surface (still air) 0.62 Total Resistance 11.54 1 Then, UR 00F =z 0.0866. Frame Flooring: House floor area = 400 ft; store floor area = 840 £7. The following table lists resistances for the floor: Location Resistance Top surface (still air) 2. Linoleum 0.05 3. Plywood, 5/8-in. 0.78 4. Air space 0.85 5. Wood subfloor, 3/4-in. 0.94 6. Bottom surface (still air) 0.61 Total Resistance = 1 = . s 2 Ww Ww W FLOOR ~ R 0.260. Adjusting for framing (2" x 8" @ 16" o.c.), Then, U Btu hr-£t*+°F UELooR x 0.94 = 0.260 x 0.94 = 0.245 Doors: The "average" house in Huslia is assumed to have two 30-in. x 80-in. doors totalling 33.33 ft*, with Uyoor = 0°49: The heat loss from the town of Huslia due to conduction and con- vection is then 5 5 Q' = = 4, = = A,U,AT, - “The following table summarizes values for A> U,, AT, for the store and houses in Huslia: D-6 Heat-Transfer Surface 1 Walls 24477.6 95 2 Windows 1842.4 95 3 Pitched roofs 18168.0 105 4 Frame flooring 12840.0 95 Doors 1033.3 rose Btu Then, Q 900,146.8 _ Heat Loss Due to Infiltration in Huslia. We assume that the average Huslia house has an infiltration factor of 1.8. If each house _is 20 ft x 20 ft x 10 ft (ignoring the attic), and the store is 28 ft x 30 ft x 20 ft (also ignoring the attic), then heat loss due to infiltra- tion is Q" = (1.8) [(30) (4000) + (1)(16800)] = 246240 = . Total heat loss Q, calculated by Method 2, is =Q'+Q"= 6 Buu, 4 Btu Q=Q'+Q' 1.146 x 10 he 1.91 x 10 a Converting to megawatts, 4 = (4.91 x 109 47-57) © 9336 sy Q 6 THERMAL Although the town is located in a region of general permafrost, the ground in Huslia is free of permafrost because of the proximity of the Koyukuk River. It is practical to consider burying the distribution piping at Huslia. We assume that the buried pipe's outside-surface temperature is maintained at a constant 33°F. The piping heat loss can then be represented as follows: 3.00 0.125 © isotherm 7.00 where = 150° = 3" = eu iieeeete Oe eceeeeeD eed ky 3 7 0-217 pathos 1, = 33°F D, = 3.25" k, , = 0.0133 —SS4, ;, hr ft °F = W D,= 7". Water temperature is estimated to be 150°F. Because of the relatively long length of piping used in Huslia, average temperature will be somewhat less, and heat loss will be lower than the value calculated here. For water at 150°F, the average properties are: Lbm Btu Q aS k = 0.381 hr ft°F t _ Lbm = u 1.04 ft he Nog 2.72. Nikolski requires a flow rate of 60 gpm, through each of two 3-in. lines => V = 1.30 ft/sec. Therefore, (1.30) (3600) (4) (61.20) Mee 7 1.04 = 6.885 x 10°. Therefore, the water flow is turbulent, with the water being cooled; n = 0.3. From McAdams, 0.8 0.3 Ny 0.028(N, ) D D (N, 2) PR = 0.023[6.885 x 10°]9-8r2.72}9*3 = 230.37; No k NU. 2 2 Do (2.3037 x 10°) (0-381) _ 3 51 x ig? = bh h : 0.25 1,2 1,2 The overall heat-transfer coefficient is then D-9 a " 3 = 0.059 . 6.65 x 1072 + 1.076 x 107-4 16.83 Heat lost from the pipe is then A S. 4 7 L Gu, (ey t Btu hr ft 5) = 12.65 Since total length of distribution piping in Huslia is expected to be 21,000 ft, total heat loss due to conduction and convection is (12.65) (21000) = 2.657 x 10° BY = 4.428 x 102 BY = 09.078 mw. hr min The following table summarizes the heat losses for Huslia: Item Loss (MW) Huslia buildings - Method 1 0.17 Huslia buildings - Method 2 0.34 Piping distribution 0.08 0.08 Total Geothermal Power Required 0.25 0.42 For system sizing and cost-estimating purposes, we use a design load of 1.0 MW. Kiana The load-sizing calculations for Kiana are very similar to the load sizing calculations for other towns located in a permafrost region. Therefore, the methods outlined here are close to the exercises for Barrow and Nome, which are not presented. Two methods are used to determine the thermal load for Kiana. Method 1 In January 1976, we estimate that the Public Health Service consumed a total of 1100 gal of No.-1 oil to operate the water and sewer facilities in Kiana. For the purposes of this study, we assume that PHS process efficiency is 0.80: ( 80 1100 gal (a-tz19° ae 1 day ( l hr (33 ret) a \_" 31 days al 24 hr/\60 min Btu/min 1 10° watt megawatt H = 4.85 * 107? sw : 1 The balance of No.-1 oil used in Kiana in January 1976 for space heating is 12,900 gal, E. The design heat loss from all heat-transfer mechanisms = HL : 2 The temperature differential for Kiana is the difference between an indoor temperature of 75° and an assumed outdoor design temperature of -35°F. The efficiency n of the average heater in Kiana is assumed to be 0.60. From historical data, there were 2300 degree days. D-11 From Chap. 43 of the ASHRAE Systems Handbook, _ _E At _n (V) L D(24) Cyc, where C,= 0.71, CE = 1.36 ; V = 1.40 x 10° Btu/gal Substituting into the above equation, y= £1:29x10*) (110) (0.60) (1. 40x10°) L (2300) (24) (0.71) (1-36) 2 = 2.236x10 "| z 6 Btu ( Lhr \ (17.57 watt (.236x10 hr ) 60 = Btu/min )( HL is then equal to THERMAL HL + HL = 0.0485 + 0.655 = 0.7035 MW 1 2 Method 2 The second technique used to size the load for Kiana is the ASHRAE heat- ing load general procedure outlined in Chap. 21 of the 1972 ASHRAE Handbook of Fundamentals. The standard ASHRAE house has been modified to reflect esti- mated construction of the average Kiana house. D-12 We estimate that 60 residences, each having a floor area of approxi- mately 20 ft x 32 ft, are to be heated by means of geothermal energy. In addition, a 14,900 te? multi-room school is to be heated, as well as an additional 30,000 ft? made up of the high school and miscellaneous buildings. For the Purposes of this study, we divide the total square footage of the buildings in Kiana into a number of "standard" Kiana buildings, each having an area of 640 et’, The total number of equivalent Standard buildings is (20 x _32)60 + 14900 + 30000 = 130 buildings . 640 120 bariding From firsthand inspection, we concluded that the "average" building in Kiana is a single-story frame structure with a raised floor and subfloor. Virtually every structure has a pitched roof. For the pur- poses of this study, we assume that 7 percent of the exterior wall sur- face of the "average" building is occupied by windows; and that all ceilings are 10 ft above the floor. For computational convenience, the "average" Kiana building will be modeled as having four exterior walls, each of which is 25 ft, 3.6 in. long. Properties of the "average" Kiana building are described below. 2 Walls. Each wall is 25 ft,. 3.6 in. * 10 ft = 253 £t°. Of the total, 7 percent is window area or 17.71 £t?; the balance of the wall area, 235.29 £t?, is modeled as follows: T= outside ° temp = (-35°F) for Kiana T. = inside = 75°F i temp The resistances for the laminated wall are listed below. eee Location Resistance Se 1. Outside surface (15-mph wind 0.17 assumed) 2. Wood siding, 1/2-in. x 8-in. 0.81 lapped (average) 3. Plywood sheeting, 1/2-in. 0.64 4. R-9 insulation 9.00 5. Gypsum wallboard, 1/2-in. 0.45 6. Inside surface (still air) 0.68 Total Resistance 11.75 SSSSSSSSSSSSSSSSSSmMFhFese 1 Btu Then, U => = 0.0851 ———~—_ wall R hr et? °F Windows. From ASHRAF (Chap. 20, Table 8) for a double-paned window: Uindow = 0.58 2 D-14 Pitched Roofs. (45° pitch assumed): Area of roof = 905.22 et? T. = -35°F ° T, = 85°F For the purposes of this heat-transfer estimate, we combine the in- sulation on the ceiling and the laminated roof into one series of thermal resistances that are treated at the roof. We assume an attic temperature of 85°F. The resistances for the laminated pitched roofs are: Location Resistance 1. Outside surface (15-mph wind 0.17 assumed) 2. Asphalt shingle roofing 0.44 3. Building paper 0.06 4. Plywood deck, 1/2-in. 0.64 5. R-9 insulation 9.00 6. Gypsum wallboard, 1/2-in. 0.45 7. Inside surface (still air) 0.62 Total Resistance 11.38 —_— Ss = + = 0.0879. Then, Deoot R D-15 Frame Flooring. 640 et’, flat area: T, = 75°F T= -35°F The resistances for the laminated floors are then, __ noo — Location Resistance See 1. Top surface (still air) 0.61 2. Linoleum 0.05 3. Plywood, 5/8-in. 0.78 4. R-9 insulation 9.00 5. Wood subfloor, 3/4-in. 0.94 6. Bottom surface (still air) 0.61 Total Resistance 11.99 eS Then, U = 4 = 0.0834. ° “floor R Doors. We assume that the "average" building has two 30-in. x 80-in. doors totalling 33.33 ft’, with a U. = 0.49 (see ASHRAE Fundamentals, DOOR Chap. 20, Table 9). The heat loss for the average Kiana building is 5 5 ' Qe > a, = > A,U, AT, rn rt. 1 i=l i=l D-16 The values for A,, U,, and AT, are summarized below. i Heat-Transfer Surface Walls 75-(-35) = 110 2 Windows 75-(-35) = 110 3 Pitched roofs 85-(-35) = 120 4 Frame flooring 75-(-35) = 110 Doors 75-(-35) = 110 a Bou, Then, Q 30,545.90 he : Heat Loss from Infiltration. We estimate that the average building in Kiana is fairly new and probably of slightly better construction than the houses in Nome. An infiltration factor of 0.90 is chosen because of the con- struction. The volume in the average Kiana building = 6400 fe, excluding the attic. The heat loss from infiltration is, from ASHRAE Fundamentals, Chap. 20, Table 7: (0.90) (6400) = 5760 ce =o". The total heat loss, Q, equals Q' + Q" = 30545.90 + 5760 = 36305.90 2 . For 130 equivalent buildings, heat loss is D-17 Btu hr Btu (130) ( 36305.90 oe) (=) = 7862.78 BEE = (7862.78) (17-57) _ 1 38 ay 1 0° THERMAL Heat Loss in Kiana Distribution Piping 3.00 7.00 2 Ss Air ® 0.125 2" thick polyurethane insulation = 3" = ° = —Btu_ D, = 3 t, = 180°F ky 3 = 0.217 pa " ° - _Btu_ D,=7 Ty = -35°F ks 4 = 0.0133 [Fg For water at t = 180°F, Lbm Btu 9 = 60.97 73 k= 0.389 SSF Lbm _ ft hr Npp = 2-16, u = 0.84 flowing 85 gpm through each of two 3" headers =>V = 3,69 Bec 1 - _ Vo | 3.69 (7) 60.57 (3600) Rey u 0.84 5. = 2.39 x 10 Therefore, the flow is turbulent with the water being cooled, => n = 0.3. D-18 From McAdams, 0.8 0.3 N = 0.023(N,_ ) (N,.) NU Rey PR = 0.023[2.39 x 10°]°°8;2.16}9"3 = 5.83 x 107. Then na. = Nuk _ (5.82 x 10) (3.89 x 107) 2 L274 = = 9.06 x 10 ' 2.5 x 10 fae eae It is assumed that the outside film coefficient, hy 5? is 1.0 > Btu/hr £t °F (assuming still air near the pipe). The overall heat transfer coefficient is then t uy, v3 Ty . ty, ln oS tr, ln ca 4 2 3 l ae ee +k cin a 2rie2 2.3 3,4 4,5 7 i = 5.574 x 10° 2 2.58 x 107-2 + 1.07 x 107! + 16.83 + 1.0 The dominant terms in U are the resistance due to the insulation and the outside film coefficient. The overall heat transfer equation and surface heat flux can be equated to yield: begets) M4 '*y > “5? D-19 Solving for ty) t= 5257 x 1072(180 - (-35)) + 1.0(-35) 4 t, = 0.23°F At = 35.23°F t_ = -17.38°F m For air at -35°F: o = 0.09344 Lb et? Btu k = 0.01220 hr for Lbm ft hr u = 0.03694 Nor = 0.727 425°R ° Then, computing the Grashof number Pier Do7geat GR ue ~ (0.583)3(0.09344)2(32.2) (3600) 2(35.23) (0.03694) 7425 4.386 x 107 D-20 ) (gg) = (4-386 x 107) (0.727) = 3.189 x 107 . or, For a horizontal cylinder: 0.25 Nyu 0.525(N Nop) y GR) PR = 39.45 _ 39.45(0.0122) _ al AL 0.583 paeee The computed value of hy 5 agrees with the assumed value within 17.4 per- cent, and is slightly overestimated. Therefore, the value of U, is ade- quate and will be used to determine overall heat loss. q Aa L” () U, (ey - ts) Btu = 21.96 hr ft Since total pipe length in Kiana is estimated to be 14,400 ft, total heat loss from piping due to conduction and convection is (21.96) (14400) = 3.16 x 10° BY. 5.97 x 192 Btu hr min ’ D-21 Heat losses for Kiana are summarized below. | Loss (MW) Item Kiana buildings - Method 1 Kiana buildings - Method 2 Piping distribution in Kiana Total Geothermal Power Required 0.7035 0.093 1.38 0.093 For system sizing and cost estimating purposes, we use a design load of 1.4 MW. Load calculations for the six towns are calculated below. Hot Side Hot Side Side Town Power | AT(°F) Flow Rate AT(°F) — <= Barrow 21.0 250-140 | 6.52x10° Lbm/hr 180-122 Huslia 150-140 3.40x10° Lbm/hr 148-120 Kiana 200-140 1.33x10° Lbm/hr 180-122 Nikolski 0.24 161-140 3.90x104 Lbm/hr 151-122 Nome 250-140 | 5.09x10° Lbm/hr | 180-122 Wrangell 250-140 2.48x10° Lbm/hr 180-122 D-22 Cold Side Flow Rate 1.24x10° Lbm/hr 1.22x10° Lbm/hr 8.24104 Lbm/hr 2.83x10° Lbm/hr 1.61%10° Lbm/hr 4.71x10° Lbm/hr Appendix E ALASKA DRILLING COSTS Information obtained to date indicates that amortized well costs will dominate the total annual cost of normal-gradient geothermal sys- tems to a much greater extent in Alaska than in the contiguous United States. A discussion of these costs, with a breakdown of incident costs, follows. COST RANGE OF PETROLEUM WELLS IN ALASKA Cost figures were obtained from the petroleum industry and from private drilling contractors in Alaska as part of independent studies by Dr. Robert Forbes and the authors of this report. Sources of informa- tion are cited where permissible; but several of our sources requested to remain unnamed because their information is proprietary. This ap- proach provides a broader information base and a means for checking the validity of the numbers. Well costs obtained independently by Dr. Forbes and the authors are in accord and up to 10 times the cost of petroleum wells in the "lower 48." The drilling costs outlined herein are based on remoteness of site, Alaska labor and materials differentials, and geo- logical information. Drilling deep holes in Alaska is very expensive; in fact, dis- proportionately expensive, when compared to the Alaska cost differen- tial for other services. For example, a 10,000-ft well recently drilled at Beaver Creek on the Kenai Peninsula cost $8,000,000. And that pro- ject is a good example of the lower end of the cost continuum, as Kenai Peninsula logistics are relatively simple compared with more remote sites. A 14,000-ft hole drilled at Cathedral River on the Alaska E-1 Peninsula cost $10,000,000; and more recently, a dry hole drilled at an offshore site in the Gulf of Alaska cost $15,000,000. One of our sources suggests $1,000,000/1,000 ft of drill hole as a working esti- mate. In Alaska, as elsewhere, cost is seen to increase with depth of drilling. Figure 1E shows well cost as a function of depth for some recent petroleum wells. COST BREAKDOWN Daily Rates Daily operating costs are quite high in Alaska. At current rates, it costs about $40,000 to $60,000/day to operate a large drill rig after it is on site. This figure is a daily rate that does not in- elude the following: l. Mobilization and demobilization; 2. Site preparation, including roads, airstrips, and campsite; as Casing; 4. Logging and testing (wire-line services); 5. Fuel; 6. Standby or yard time on the drill rig, after it is committed and before it is moved to the site. The daily rate will vary depending on the remoteness of the site, number of people in the camp, and whether the hole progresses at a normal rate without complications (jammed drill strings, etc.) re- quiring delays and the services of specialty crews that must be brought in to the site. Daily rates comprise drilling contractor's fees for E-2 Well cost (millions of dollars) 100 90 80 70 60 50 40 30 20 a vn ™~ OWO > Nome Alaska (location not specified) Kenai Peninsula Cold Bay Alaska Peninsula 5 6 7 8 9 10 11 12 13 14 15 Well depth (thousands of feet) Fig. lE--Well cost as a function of depth for recently drilled petroleum well in Alaska E-3 rig time, bits and drilling materials, personnel and crews, and trans- portation of workers to Anchorage or another home base for one-week-on/ one-week-off work periods (with 12-hr daily shifts). Based on rock types and formations at the six sites, we estimate that drilling times will range from 80 to 100 days if no major diffi- culties are encountered. Estimates of the minimum number of days of drilling at each site, along with site-specific mobilization and de- mobilization costs, will allow us to approximate the drilling costs for each location in the final report. Mobilization and Demobilization The cost of drilling in Alaska varies greatly with the location of the well. Mobilization costs include transportation of rigs and other drilling equipment, steel casings, cement, drilling fluids, fuel, and materials for support facilities. (Demobilization, costing about 70 percent of mobilization for petroleum drilling operations, includes mandatory cleaning up and revegetation of the site, where necessary, in addition to removing rigs, etc.) Such costs, which are much greater than in the lower 48 states, are a contributing factor to the high cost of drilling in Alaska. To drill a well at a remote Alaskan location, it is necessary to barge or fly in equipment. All six study sites are accessible by barge (usually originating in Seattle or California). Barge rates for ship- ping drilling equipment are substantially lower than air transport, but often far less convenient. Shipping to those locations lacking deep-sea ports, for example, involves additional lighterage fees. Rig time is less costly while in transit than when in operation, but r cost of downtime must be considered for the time that equipment is on the barges. Scheduling must be done well in advance of the antici- pated drilling season and is limited to the short summer, during which the major rivers are navigable (for Huslia and Kiana), and when the ice pack is open (Nome and Barrow). Conversely, land transportation of construction and drilling equipment where no roads exist is best accomplished during winter months (when the tundra is frozen). Air transportation is usually accomplished with Hercules cargo air- craft having a 45,000-lb capacity. These aircraft require a 5000-ft airstrip for landing and take-off under full load. All six sites, except Huslia, have acceptable airstrips. (The airstrip at Huslia, only 3000-ft long, would need lengthening to make it suitable for "Hercs.") Since drill sites for this study are assumed to be chosen on the bases of nearness to the center of population, geological considera- tions, land use and availability, accessibility via roads, and prox- imity to the airstrip or dock, road-building costs are not a major mobilization consideration. Although the direct cost of air mobilization averages $1,000,000 for the six study sites and direct barge costs are only half this fig- ure, the additional difficulties of barging make air transportation less expensive and the mode of choice for Nome, Barrow, Kiana, and Nikolski. Wrangell has good port facilities and is easily accessible by barge from Seattle. Huslia's airstrip could be improved without great cost should barging logistics prove difficult. E-5 J. H. McKeever, Amoco Production Company, Anchorage, has supplied the following rough cost estimates for a project involving an 8,000- to 10,000-ft hole to be drilled on the Seward Peninsula, including the various phases of work that might be required at a remote site: Drilling $1,500,000 Standby 500,000 Mobilization and Demobilization Barge 2,000,000 Air (Hercules) 1,500,000 Dirt Work Winter 1,500,000 All weather 3,000,000 Airstrip (Hercules) if necessary 1,500,000 Casing 500,000 Logging and testing 500,000 Fuel 1,000,000 Mr. McKeever also notes that daily costs had risen to $65,000 in 1977 on one Amoco well in Alaska. If two holes are drilled at one site, the total cost will of course be reduced about 25 percent by the simplified logistics of the second hole; but there will be costs associated with moving the rig to the second site, and the $40,000-$60,000/day rate will still apply. Note that the above cost estimates do not include the wellhead and downhole hardware that would be required in a completed geothermal well. One of our sources has cited $1,000,000 as the cost of casing and wellhead hardware for a 10,000-ft hole. Two sources agreed that drill rigs could not be brought into Nome and evacuated for less than $1,000,000. Availability of Drill Rigs Drilling rigs must be of the sort that can be broken down to fit into a "Herc" or onto a barge. About three or four suitable drill rigs are available in Alaska for contract drilling. Ome is in Fairbanks; the others, in Kenai. Drill rigs have to be requisitioned a long time in advance; and once the rig is committed, the user pays about $1000/day standby time. This fee is also charged during transit time to the site. Alternative possibilities include moving drill rigs down from Barrow or north from California. One means of decreasing the cost of drilling is to engage a rig that is already in the area and thus cut mobiliza- tion costs. The relative cost of drilling geothermal wells in the six Alaskan towns and villages will of course be related to accessibility and geo- technical requirements. Logistically, the sites with nearby airports and/or port facilities will be the least expensive. For example, rigs could be flown directly from Kenai to Nome, Barrow, and Kiana; but would probably be barged to Huslia. The decision on barging versus airlift for Nikolski would have to be based on comparative cost esti- mates. For Wrangell, it would probably be less expensive to transport a rig via barge from California than to relocate an Alaskan rig. E-7 The Nome Model We assume that a well can be drilled a short distance from the Nome airport and that the drill rig will be flown in by Hercules air- craft from Kenai. The crews may be housed and fed in Nome, obviating the construction of a large camp. Two 10,000-ft holes are to be drilled and cased, one-quarter mile apart, with the usual logging and testing services. Estimated costs are as follows: Airlift of rig from Kenai to Nome, and mobilization on site No. l $ 500,000 60 days drilling time @ $40,000/day 2,400,000 Casing 500,000 Logging and testing 500,000 Fuel 500,000 Moving of rig to site No. 2 500,000 60 days drilling time @ $40,000/day 2,400,000 Casing 500,000 Logging and testing 500,000 Demobilization of rig and transport back to Kenai 500,000 Total cost for two holes $9,310,000 Subtotal for one hole $5,400,000 This cost model utilizes minimum incident costs and is a very conserva- tive estimate when compared with the actual well costs discussed above. $5,400,000 may be considered the bottom-line cost for a 10,000-ft well at Nome. Relative Costs at Other Sites At Wrangell, costs would be 20-percent less than those at Nome; and more at Huslia, Barrow, and Kiana. Nikolski costs would probably be about the same as those at Nome. Holes drilled in soft sedimentary rather than harder metamorphic rocks would proceed at more rapid drilling rates, and (without compli- cations) would require less rig time. For example, two years ago the Nimiuk Point No.-l well near Kotzebue was drilled to 6311 ft and aban- doned in 53 days. However, most holes in harder rocks will require more time. Therefore, the 60-day estimate used in the above cost break- down is quite optimistic.