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HomeMy WebLinkAboutG00b-ElfinReconReport_FINAL(lo-res)_mod cover HYDROELECTRIC RECONNAISSANCE STUDY ELFIN COVE, ALASKA FINAL REPORT JUNE 2010 Prepared by POLARCONSULT ALASKA, INC. 1503 WEST 33RD AVENUE, SUITE 310 ANCHORAGE, ALASKA 99503 Prepared for NON-PROFIT COMMUNITY OF ELFIN COVE P.O. BOX 1 ELFIN COVE, ALASKA 99825 THIS PROJECT WAS FINANCED BY THE DENALI COMMISSION AND ITS PARTNERS, THE ALASKA ENERGY AUTHORITY AND THE ELFIN COVE UTILITY COMPANY. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT I EXECUTIVE SUMMARY The Non-profit Community of Elfin Cove (Elfin Cove) retained Polarconsult Alaska, Inc., (Polarconsult) to complete a reconnaissance study of hydroelectric resources for Elfin Cove. Elfin Cove is interested in developing local hydroelectric resources to reduce the community’s current total dependence on diesel fuel for electrical generation. The purpose of this report is to assist the community in evaluating potential hydroelectric projects. Based on field investigations and analyses of resource suitability and community needs, recommendations are provided for additional investigation and development activities. Polarconsult evaluated six potential hydroelectric projects in the immediate vicinity of Elfin Cove. These potential projects are: ¾ A run-of-river project on Crooked Creek; ¾ Three configurations of a storage project at Crooked Creek and Jim’s Lake; ¾ A run-of-river project at Roy’s Creek; and ¾ Simultaneous development of run-of-river projects at Roy’s, Joe’s and Ernie’s Creek. Each of these hydroelectric projects appears technically feasible. Projects at Crooked Creek, Crooked Creek/Jim’s Lake, and Roy’s Creek appear to offer the greatest benefits to Elfin Cove and have the highest estimated benefit-to-cost ratios. At the current level of study, it is not possible to determine which of these projects would best suit the community. Continued investigation of projects at all three resources is warranted. Smaller projects at Joe’s Creek and Ernie’s Creek were considered in conjunction with a project at Roy’s Creek. Analysis of these projects determined that their projected incremental reduction in diesel fuel usage did not justify their estimated costs. Of the projects that warrant continued study, a project at Crooked Creek and Jim’s Lake is projected to achieve the greatest reduction in diesel fuel usage. That project also has the highest estimated capital costs. A run-of-river project at Roy’s Creek is projected to achieve the smallest reduction in diesel fuel usage, but is estimated to have the lowest capital cost and highest benefit-cost ratio. Findings for projects that warrant continued study are summarized below. Attribute Crooked Creek (run-of-river) Crooked Creek and Jimʹs Lake (storage) Royʹs Creek (run-of-river) Conceptual Project Design Flow 5 cfs 9 cfs 4 cfs Estimated Gross Head 450 ft 315 ft 450 ft Maximum Probable Installed Capacity 120 kW 150 to 200 kW 100 kW Estimated Installed Cost $1.6 – 2.5M $1.6 – 3.6M $1.1 – 1.6M Estimated Annual Diesel kWh Displaced 276,000 kWh (79% of total) 313,000 – 344,000 kWh (89-97% of total) 216,000 kWh (62% of total) Estimated Annual Diesel Fuel Displaced 22,100 gal 25,000 – 27,400 gal 17,300 gal Estimated Annual Net Excess Energy 196,000 kWh 138,000 – 299,000 kWh 107,000 kWh Estimated Benefit-Cost Ratio 0.7 – 1.3 0.6 – 1.4 0.8 – 1.5 Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT II Further investigation of hydroelectric resources for Elfin Cove should include: ¾ Continued hydrology data collection & analysis; ¾ Completion of topographic and geotechnical surveys; ¾ Consultation with resource agencies and the Federal Energy Regulatory Commission (FERC) to investigate permitting issues, identify any necessary field studies, and decide on the best FERC licensing process for the projects; ¾ Assessment of project sizing and integration with the communityʹs existing energy infrastructure to maximize utilization of energy produced by the projects; ¾ Completion of conceptual designs and investigate potential construction methods and costs; ¾ Development of project cost estimates; ¾ Refinement of project economics and determination of the preferred project; and ¾ Investigation of options for project financing. These activities will be documented in a feasibility study for the preferred hydroelectric project for the community. A client review draft of this report was provided to Elfin Cove in March 2010. Elfin Cove met on May 28, 2010 and voted to pursue the Jim’s Lake Option 2C as presented in this study. Option 2C is located approximately one mile south of Elfin Cove, and generally includes a run- of-river hydroelectric project between Crooked Creek and Jim’s Lake, and a second storage hydroelectric project between Jim’s Lake and tidewater. This project is projected to displace 97% of the community’s diesel-fired electrical generation with renewable hydropower, at an estimated capital cost of $2.5 to 3.6 million. Minutes of the community meeting are included in Appendix G. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT III TABLE OF CONTENTS ACRONYMS AND TERMINOLOGY..................................................................................................................V 1.0 INTRODUCTION.......................................................................................................................................1 1.1 PROJECT EVALUATION PROCESS ...............................................................................................................1 1.2 SUMMARY OF INVESTIGATIONS .................................................................................................................2 1.3 COMMUNITY BACKGROUND .....................................................................................................................3 1.4 ELFIN COVE ENERGY PROFILE ...................................................................................................................3 2.0 PREVIOUS STUDIES.................................................................................................................................7 2.1 CROOKED CREEK RUN-OF-RIVER PROJECT ...............................................................................................7 2.2 CROOKED CREEK AND JIM’S LAKE DIVERSION AND STORAGE PROJECT .................................................7 2.3 ROY’S CREEK RUN-OF-RIVER PROJECT .....................................................................................................8 2.4 JOE’S CREEK & ERNIE’S CREEK RUN-OF-RIVER PROJECTS ........................................................................9 2.5 MARGRET CREEK RUN-OF-RIVER PROJECT ...............................................................................................9 3.0 ANALYSIS OF PROJECTS......................................................................................................................10 3.1 COMMON PROJECT CONSIDERATIONS AND DATA .................................................................................12 3.2 CROOKED CREEK RUN-OF-RIVER PROJECT .............................................................................................13 3.3 CROOKED CREEK AND JIM’S LAKE DIVERSION AND STORAGE PROJECT ...............................................16 3.4 ROY’S CREEK RUN-OF-RIVER PROJECT ...................................................................................................21 3.5 SIMULTANEOUS DEVELOPMENT OF ROY’S, ERNIE’S AND JOE’S CREEK PROJECTS .................................22 4.0 ECONOMIC ANALYSIS.........................................................................................................................23 5.0 CONCLUSIONS AND RECOMMENDATIONS ...............................................................................25 5.1 REMAINING TECHNICAL CONSIDERATIONS ...........................................................................................25 5.2 CONCLUSIONS ..........................................................................................................................................27 5.3 DEVELOPMENT PLAN & SCHEDULE ........................................................................................................27 APPENDICES APPENDIX A – PROJECT MAPS APPENDIX B – PHOTOGRAPHS APPENDIX C – HYDROLOGY APPENDIX D – ENVIRONMENTAL CONSIDERATIONS APPENDIX E – PERMITTING APPENDIX F – ASSUMPTIONS USED FOR ECONOMIC ANALYSIS APPENDIX G – MINUTES OF ELFIN COVE COMMUNITY MEETING – MAY 28, 2010 LIST OF TABLES Table 2-1: Existing Utility Generation Equipment ...............................................................................4 Table 3-1: Summary of Evaluated Hydro Projects.............................................................................11 Table 3-2: Effect of Jim’s Lake Storage on Hydroelectric Generation..............................................16 Table 4-1: Assumptions Used for Economic Analysis of Hydro Projects.......................................23 Table 4-2: Summary of Estimated Economic Data for Evaluated Hydroelectric Projects............24 Table C-1: Summary of Hydrology Data for Elfin Cove Hydroelectric Resources.....................C-1 Table C-2: Flow Measurements for Elfin Cove Hydroelectric Resources.....................................C-2 Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT IV LIST OF FIGURES AND PHOTOGRAPHS Figure 2-1: Recent Elfin Cove Power Generation Data........................................................................5 Figure 2-2: Recent Elfin Cove Fuel Usage and Expenses ....................................................................6 Figure 3-1: Estimated Average Monthly Energy Provided by Hydro Projects...............................10 Figure 5-1: Project Development Schedule..........................................................................................28 Figure A-1: Project Overview and Location Map ............................................................................A-1 Figure A-2: Crooked Creek Run-of-River Project Map ...................................................................A-2 Figure A-3: Crooked Creek-Jim’s Lake Options A and B Project Map .........................................A-3 Figure A-4: Crooked Creek-Jim’s Lake Option C Project Map.......................................................A-4 Figure A-5: Roy’s Creek, Joe’s Creek, and Ernie’s Creek Project Map...........................................A-5 Photograph B-1: Aerial View of Small Sandy Beach, Jim’s Lake, and Crooked Creek...............B-1 Photograph B-2: Crooked Creek Gauging Station, Looking Upstream........................................B-1 Photograph B-3: Crooked Creek Gauging Station, Looking Downstream...................................B-2 Photograph B-4: Crooked Creek 50 Yards Above Gauging Station, Looking Upstream...........B-2 Photograph B-5: Site for Crooked Creek Diversion Outlet or Upper Powerhouse.....................B-3 Photograph B-6: Jim’s Lake Looking West from Lake Outlet.........................................................B-3 Photograph B-7: Jim’s Lake Gauging Station....................................................................................B-3 Photograph B-8: Typical View of Power Line Route Between Jim’s Lake and Elfin Cove........B-4 Photograph B-9: Soils Along Power Line Route Between Jim’s Lake and Elfin Cove................B-4 Photograph B-10: Crooked Creek Gauging Station, Looking Upstream......................................B-4 Photograph B-11: Roy’s Creek Running Over Bedrock Above Falls.............................................B-5 Photograph B-12: Roy’s Creek Gauging Station...............................................................................B-5 Photograph B-13: Roy’s Creek Waterfall...........................................................................................B-5 Photograph B-14: Debris Field Upstream from Crooked Creek Intake Site.................................B-6 Photograph B-15: Debris Field in Elfin Cove....................................................................................B-6 Photograph B-16: Debris Field along Power Line Route.................................................................B-6 Figure C-1: Jim’s Lake Storage Curve................................................................................................C-3 Figure C-2: 1984 - 1985 Crooked Creek Recorded Stage and Calculated Flow Data...................C-7 Figure C-3: 2008 – 2009 Crooked Creek Recorded Stage and Calculated Flow Data..................C-8 Figure C-4: Flow Duration Curves for Crooked Creek ...................................................................C-8 Figure C-5: 1984 - 1985 Jim’s Lake Outlet Recorded Stage and Calculated Flow Data..............C-10 Figure C-6: 2008 - 2009 Jim’s Lake Outlet Recorded Stage and Calculated Flow Data.............C-10 Figure C-7: Flow Duration Curves for Jim’s Lake Outlet..............................................................C-11 Figure C-8: 2009 Roy’s Creek Recorded Stage and Calculated Flow Data..................................C-13 Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT V ACRONYMS AND TERMINOLOGY ADCED Alaska Department of Community and Economic Development ADEC Alaska Department of Environmental Conservation ADFG Alaska Department of Fish and Game ADNR Alaska Department of Natural Resources AEA Alaska Energy Authority AEA / REG Alaska Energy Authority Rural Energy Group APA Alaska Power Authority (predecessor to AEA) cfs cubic feet per second COE U.S. Army Corps of Engineers CPCN Certificate of Public Convenience and Necessity ECUC Elfin Cove Utility Commission Elfin Cove Non-Profit Community of Elfin Cove Environmental attributes The term environmental attributes is used by the green power industry to describe the desirable aspects of electricity that is generated by environmentally benign and/or renewable sources. Environmental attributes are tracked, marketed, bought and sold separately from physical energy. Separating the environmental attributes enables customers of a given utility system to elect to buy sustainable or ‘green’ energy even if it is unavailable from their utility. FERC Federal Energy Regulatory Commission Flow duration curve The flow duration curve is a curve that indicates how often a creek flows at or greater than a given flow rate. ft foot, feet FY fiscal year Hatch Hatch America, Inc. HDPE high-density polyethylene Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT VI in inch, inches Jim’s Lake A small lake located approximately one mile south of Elfin Cove. Previous studies refer to this lake as ‘Jim’s Lake’, and that name is used in this study. The local name for the lake is ‘Elfin Lake’. kV kilovolt, or 1,000 volts kVA kilovolt-amp kW kilowatt, or 1,000 watts. One kW is the power consumed by ten 100-watt incandescent light bulbs. kWh kilowatt-hour. The quantity of energy equal to one kilowatt (kW) expended for one hour. Mass wasting The geomorphic process by which soil and rock move down slope under the force of gravity. mi mile, miles MW megawatt, or 1,000 kilowatts NREL National Renewable Energy Laboratory PCE Power Cost Equalization Program Penstock A pipeline used to convey water to a hydropower turbine. Polarconsult Polarconsult Alaska, Inc. PLC programmable logic controller RCA Regulatory Commission of Alaska run-of-river A hydroelectric project that has little or no water storage capacity. The project diverts the instantaneous flow of a river or creek for electrical generation. When the river or creek is low, the project produces less electricity. SWPPP stormwater pollution prevention plan Tailrace The structure used to carry water away from a hydropower turbine and to the receiving water body. The tailrace can be a pipe, ditch, flume, or other structure. USGS U.S. Geological Survey V volt Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 1 1.0 INTRODUCTION The community of Elfin Cove is evaluating hydroelectric projects in order to lower their electricity costs. Electricity costs have risen in recent years due to increases in the cost of the diesel fuel that the community uses for electricity generation. Through the use of a renewable hydroelectric resource, the community will benefit from a reduced dependence on diesel fuel. Elfin Cove retained Polarconsult Alaska, Inc. (Polarconsult) to conduct a reconnaissance study of hydroelectric resources that could provide economical electricity to Elfin Cove. This report presents the findings of previous studies, new field investigations, analysis of potential project configurations and resource availability, and a review of community power needs. The initial project focus was on evaluation of a project at Crooked Creek and Jim’s Lake.1 This was based on the recommendations of previous studies and the technical attributes of these resources, specifically the storage and regulation offered by Jim’s Lake and superior hydrology at Crooked Creek. Field investigations in 2009 indicated that Roy’s Creek also warranted consideration, and this report analyzes both the Crooked Creek/Jim’s Lake and Roy’s Creek resources. Recommendations are provided to guide future development of a hydroelectric project to meet Elfin Cove’s energy needs. Polarconsult prepared this report under the June 22, 2009 contract with Elfin Cove. Funding for this project is a combination of community funds and a grant from the Denali Commission. The Denali Commission grant is administered by the Alaska Energy Authority (AEA). 1.1 PROJECT EVALUATION PROCESS Prospective hydroelectric projects were evaluated through an iterative process that began with review of existing data, previous reports, and new field investigations conducted in 2009. Project evaluation criteria emphasized maximizing energy generation, technical feasibility, and economic viability. Those projects that appeared technically feasible and economically beneficial warrant further investigation. Prospective projects that failed to meet these criteria have been eliminated through this process. This process has determined that projects at Roy’s Creek, Crooked Creek, and Crooked Creek/Jim’s Lake appear to be technically feasible, are estimated to provide substantial benefits to Elfin Cove, and have favorable benefit-cost ratios. These projects warrant consideration for further investigation. A client review draft of this report was provided to Elfin Cove in March 2010. Elfin Cove met on May 28, 2010 and voted to pursue the Jim’s Lake Option 2C as presented in this study. Minutes of the community meeting are included in Appendix G. Under its existing contract with Elfin Cove, Polarconsult will conduct a feasibility study for this project configuration. 1 Jim’s Lake is a small lake located approximately one mile south of Elfin Cove. Previous studies called this lake Jim’s Lake and that name is used in this study. This lake is also known locally as ‘Elfin Lake’. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 2 1.2 SUMMARY OF INVESTIGATIONS Polarconsult’s initial review and analysis of hydroelectric resources for Elfin Cove began in May 2009 with collection and review of past studies and other available resource information. This included analysis of technical documentation on the recent electrical system upgrades, aerial imagery of the project area, and available environmental and topographic data for the area. Following review of this information, Polarconsult engineers Joel Groves, PE, and Dan Hertrich, PE, visited Elfin Cove from July 6 to July 9, 2009 to conduct reconnaissance-level field investigations of several local hydroelectric resources. Based on past studies and available data, field investigations during this visit focused on the Crooked Creek/Jim’s Lake resource. Activities during this field trip included: ¾ gathering information on the existing electrical system and load profile; ¾ hiking the power line route from Elfin Cove to the Crooked Creek / Jim’s Lake area; ¾ hiking from the tidewater powerhouse site to Jim’s Lake; ¾ hiking from Jim’s Lake to the Crooked Creek diversion site; ¾ measuring stream flows at the Crooked Creek diversion site and Jim’s Lake outlet; ¾ measuring the bathymetry of Jim’s Lake; and ¾ surveying the differential elevations between the Crooked Creek diversion site, Jim’s Lake, and tidewater powerhouse site. Mr. Groves later visited Elfin Cove from September 3 to September 5, 2009 to hold a community meeting and present preliminary reconnaissance-level findings. During this visit, Mr. Groves measured stream flow at Crooked Creek and Jim’s Lake to continue calibration efforts at these gauging stations. Mr. Groves also measured flow at Roy’s Creek to ascertain whether this resource warranted consideration. The community meeting was held on September 4. Based on the presentation of Polarconsult’s initial findings, the community passed a resolution supporting the additional investigation of Roy’s Creek. Mr. Groves again visited Elfin Cove from October 7 to October 10, 2009 to upgrade the existing stream-gauging installations at Crooked Creek and Jim’s Lake and to install a stream gauge at Roy’s Creek. Flows were measured at all three sites to calibrate the gauging stations. Mr. Bob Christensen of Living Systems Design, LLC in Gustavus was hired to assist with gauge installations. On December 9, 2009, Mr. Christensen and Ms. Jane Button, the Elfin Cove Utility Commission (ECUC) manager for this project, visited all three gauging stations to measure flows and download data. The results of the 2009 field investigations, analysis of preliminary hydrology data, reconnaissance level analyses, findings, and recommendations are presented in this report. In May 2010, the Elfin Cove community met and selected option 2C at Jim’s Lake for continued study. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 3 1.3 COMMUNITY BACKGROUND Elfin Cove is an unincorporated community located on the northern shore of Chichagof Island, 70 air miles west of Juneau and 33 air miles west of Hoonah. It is located at latitude 58 19.44ʹ north, longitude 136 34.33ʹ west, which is approximately 520 air miles southwest of Anchorage. Figure A-1 in Appendix A shows the location of Elfin Cove and its surroundings. The community’s population fluctuates seasonally. The winter population (September through May) is 10 to 20, and the summer population (May through September) is approximately 100 to 200. There are several seasonally-operated fishing lodges in Elfin Cove that contribute to the large increase in summer population. Elfin Cove is located in a maritime climate, with relatively cool summers and mild winters. Normal summer temperatures range from the lower 50s to mid 60s, and normal winter temperatures range from the mid 20s to high 30s. Recorded temperature extremes are -10F to +85F. Total average annual precipitation is 102 inches, with 96 inches of snowfall. The community is accessible by seaplane or watercraft. Elfin Cove does not have road access or an airport runway. Scheduled and charter air service is available from Juneau. Marine transport is available from local operators. Elfin Cove is not currently served by the Alaska Marine Highway System. Elfin Cove is located in the Chatham School District, and has a local school/community building. The community does not currently have enough students to receive state funding for operating the school. Residents have formed a non-profit association to provide public services within Elfin Cove, including the water system, a diesel power plant and electric distribution system, bulk fuel facility, and harbor. There is no landfill or centralized sewer system in the community. 2 1.4 ELFIN COVE ENERGY PROFILE 1.4.1 Community Energy Infrastructure 1.4.1.1 Electric Utility Organization Electrical service in Elfin Cove is provided by the ECUC, which is owned by the Non-Profit Community of Elfin Cove (NPCEC).3 The ECUC holds Certificate of Public Convenience and Necessity (CPCN) No. 701, issued by the Regulatory Commission of Alaska (RCA) in 2004, authorizing it to operate as a public utility providing electrical service in and around Elfin Cove. 2 Compiled from the Alaska Department of Community and Economic Development (ADCED) Community Profile for Elfin Cove. 3 Elfin Cove does not have a formally-organized local government. The NPCEC provides essential government services to the community. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 4 The RCA has exempted the ECUC from regulation other than certification on public interest grounds as allowed by AS 42.05.711(d). The ECUC participates in the State of Alaska’s Power Cost Equalization (PCE) program, which subsidizes electricity rates for residential and community facilities served by eligible rural Alaska utilities. Elfin Coveʹs energy infrastructure is relatively new. A new bulk-fuel facility was constructed in 2000, the diesel power plant was replaced in 2007, and the communityʹs electrical distribution system was upgraded in 2009. The diesel power plant provides waste heat to the adjacent community building and shop.4 1.4.1.2 Electrical Generation System ECUCʹs diesel power plant is located in the heart of the community. The plant has three generators controlled by four sections of switchgear. The switchgear is fully automatic with paralleling capability, and uses a programmable logic controller (PLC) to match the generator(s) to system load. The plant generates three-phase electricity at 480 volts. Installed utility generation equipment in Elfin Cove is listed in Table 2-1. Several of the lodges own and maintain separate back-up generators. These private generators are not configured to parallel with the utility system. Table 2-1: Existing Utility Generation Equipment No. Equipment Prime Power (kW) Commissioned Date Designated Use 1 John Deere 6081 179 kW 2007 Summer peak 2 John Deere 6068 101 kW 2007 Summer intermediate 3 John Deere 4045 67 kW 2007 Winter load 1.4.1.3 Electrical Distribution System The ECUC electric distribution system was upgraded in 2009. The system is a 7,200-volt grounded wye three-phase system without loop feed. Most of the system is run in shallow burial or surface-laid cable in duct. Distribution along the west side of the cove is overhead on wooden poles. The 480-volt power plant bus is stepped up to 7,200 volts using a single 225 kVA pad-mount transformer. 4 Concept Design Report and Construction Cost Estimate for Energy Infrastructure Projects in the Community of Elfin Cove, Report for the Alaska Energy Authority / Rural Energy Group (AEA/REG), Prepared by Alaska Energy and Engineering, Inc. February 2006. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 5 0 50 100 150 200 250 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09 Jan-10Monthly Peak kW Monthly Average kWPeak Monthly Power Demand Average Monthly Power Demand 1.4.2 Existing and Projected Future Electric Load Profile ECUC electric demand varies significantly by season. Several lodges operate in the community during the summer (May through September), creating an average load of 60 to 80 kilowatts (kW) and peak loads up to 240 kW. During the winter (September through May), the lodges are closed, and many residents leave town. Average wintertime load is 15 to 30 kW, with peak loads up to 60 kW. The past seven years of load data are presented in Figure 2-1. Elfin Coveʹs population has fluctuated in recent years between 10 to 60 full-time residents. The summer population is consistently much higher due to fishing lodge clientele. Future load trends are expected to be similar to recent experience. This report assumes no future growth in ECUC load. Elfin Coveʹs annual consumption of diesel fuel for electrical generation was generally uniform from 2004 through 2008, varying from 30,000 to 33,000 gallons annually. Fuel consumption in 2009 was 14% lower than in earlier years at 26,413 gallons. Figure 2-1: Recent Elfin Cove Power Generation Data Potential hydroelectric projects were evaluated using a model of ECUC system loads. Monthly and annual average and peak ECUC system load data was used to calibrate the ‘Alaska Village Electric Load Calculator’, a program developed by the National Renewable Energy Laboratory (NREL).5 5 See NREL Technical Report #36824 at www.nrel.gov/publications for documentation on this model. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 6 $20,000 $40,000 $60,000 $80,000 $100,000 $120,000 $140,000 $160,000 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09 Jan-10Annual Fuel Usage Annual Cost of Fuel$0.00 $1.00 $2.00 $3.00 $4.00 $5.00 $6.00 $7.00 $8.00 $9.00 Monthly Price of Fuel ($ per gallon)Annual Cost of Fuel Annual Diesel Usage Monthly Price of Fuel Because of the large variance in ECUC’s loads between summer and winter, the model was calibrated to each season separately and these datasets were combined into a single dataset. The resulting load model provides hourly system demand. 1.4.3 Energy Market During the summer of 2009, the retail cost of electricity in Elfin Cove was $0.56 per kilowatt- hour (kWh). PCE subsidies reduce the cost of electricity for residential customers (up to 500 kWh monthly) from $0.20 to 0.30 per kWh. Commercial customers receive no state subsidy, and pay the full rate. Fuel is delivered to Elfin Cove by barge. Historical fuel prices, costs, and consumption are presented in Figure 2-2. Between 2003 and 2007, fuel prices roughly doubled from approximately $2.00 per gallon to $4.00 per gallon. The cost of fuel in Elfin Cove reached a high of $5.94 per gallon in the summer of 2008, and has since remained relatively stable at about $4.00 per gallon.6 By developing the local hydroelectric project(s) considered in this study, Elfin Cove will reduce its dependence on diesel fuel which is expected to remain expensive and volatilely-priced in the future. This will strengthen the community’s economy and long-term viability. Figure 2-2: Recent Elfin Cove Fuel Usage and Expenses 6 ECUC system demand and fuel cost data obtained from ECUC reports and PCE program reports. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 7 2.0 PREVIOUS STUDIES Several previous studies have reviewed a variety of hydroelectric resources for Elfin Cove: ➘ A 1979 regional reconnaissance study completed by CH2M Hill, Inc. for the U.S. Army Corps of Engineers (COE) reviewed hydroelectric resources in the vicinity of Elfin Cove. This study identified a 310-kW run-of-river hydroelectric project at Margret Creek, 6.4 miles from Elfin Cove. ➘ A 1984 reconnaissance study of energy alternatives and requirements for Elfin Cove completed by Hatch America, Inc. (Hatch) for the Alaska Power Authority (APA). This study considered the hydroelectric resources within Elfin Cove – Roy’s Creek, Joe’s Creek and Ernie’s Creek – and recommended further investigation of a 20 to 60 kW run- of-river hydroelectric project at Roy’s Creek in Elfin Cove. ➘ A 1984 APA supplement to the Hatch study considered the hydroelectric resources in Elfin Cove – Roy’s Creek, Joe’s Creek and Ernie’s Creek – to not be feasible and recommended further investigation of a project about one mile south of Elfin Cove. This project was an 80-kW hydroelectric project from Jim’s Lake to tidewater with a diversion from Crooked Creek to Jim’s Lake. The following is a summary of projects that have been previously considered for hydro power development. 2.1 CROOKED CREEK RUN-OF-RIVER PROJECT The 1984 APA supplemental report mentioned a stand-alone run-of-river hydroelectric project at Crooked Creek. This alternative did not receive in-depth consideration in 1984 because the combined Crooked Creek and Jim’s Lake resource was considered to have the potential to provide all of the community’s projected electrical needs. By comparison, the Crooked Creek watershed was judged to have no storage and to lack a suitable dam site to create storage, thus presenting an inferior energy alternative. Because Elfin Cove now has a modern diesel power plant, a run-of-river hydro project at Crooked Creek warrants review and is considered as a part of this reconnaissance study. 2.2 CROOKED CREEK AND JIM’S LAKE DIVERSION AND STORAGE PROJECT The 1984 APA supplemental report recommended a project at Crooked Creek and Jim’s Lake, approximately one mile south of Elfin Cove. As conceptualized by APA, this would be a storage project with a 1,650-foot long by 18-inch diameter diversion pipeline from Crooked Creek to Jim’s Lake. A small weir and/or siphon would be installed at Jim’s Lake. A 2,400-foot long by 12-inch diameter penstock would run from the lake to a powerhouse located at tidewater at ‘Small Sandy Beach’ (local name). The project has 330 feet of net head, a design flow of 4.5 cubic feet per second (cfs), and an installed Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 8 capacity of 80 kW. Electricity was to be transmitted from the powerhouse to Elfin Cove via a surface-laid 6,700 foot single-phase 7,200 volt cable in flexible duct. The annual energy output of the project was estimated at 141,000 kWh. APA also estimated that the project could meet all of the community’s electricity needs and eliminate the need for a central diesel power plant. APA estimated a project capital cost of $400,000 (1984 dollars). This cost estimate assumed use of local labor and materials, and minimal use of heavy equipment for construction. Materials would be staged by helicopter or obtained locally and the project would largely be built by manual labor. Based on the APA recommendations, the Alaska Department of Natural Resources (ADNR) installed stream gauges at the proposed Crooked Creek diversion site and Jim’s Lake outlet in 1984. Data from these gauges is available from August 1984 through February 1985. More recently, ECUC installed new stream gauges at these same locations in 2008 and Polarconsult upgraded these installations in 2009. These stream gauges remain in service. Analysis of this hydroelectric resource indicates that it is too small to provide all of the community’s current electrical demand, but it does have the potential to significantly reduce the community’s diesel fuel usage, and therefore warrants consideration in this study. 2.3 ROY’S CREEK RUN-OF-RIVER PROJECT The 1984 Hatch reconnaissance study recommended a 20 to 60 kW run-of-river project at Roy’s Creek in Elfin Cove. As conceptualized by Hatch, this would be a run-of-river project with a penstock running from a diversion at an elevation of 320 feet to a powerhouse at tidewater. The project would use the 320 feet of head and a design flow of 1 to 3 cfs to generate 20 to 60 kW. Because the powerhouse would be located within the community, electricity would be fed into the local distribution system. The project was estimated to reduce the community’s diesel fuel demand at a centralized power plant by 60%. Hatch estimated the capital cost of a 40-kW project at Roy’s Creek to be $200,000 (1984 dollars). APA’s 1984 supplemental report concluded that a project at Roy’s Creek was likely not feasible due to reports that the creek experiences extended periods of low or no flows and frequent dangerous floods. These findings were based on daily qualitative observations of flows in Roy’s Creek at the footbridge near tidewater. While the observed flows at the footbridge in Elfin Cove support the conclusions in the 1984 APA study, flows at the elevation where an intake would be located appear more favorable for a hydroelectric project. On September 3, 2009, Polarconsult measured 1.06 cfs just above the waterfall at an elevation of 300 to 350 feet. Concurrent flows at the footbridge appeared much Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 9 lower. This measured flow would be sufficient to generate approximately 20 kW of power from Roy’s Creek. Roy’s Creek runs over exposed bedrock in the intake vicinity, and is expected to have very little subsurface flow. In the vicinity of the footbridge, there is a significant deposit of coarse alluvial material, and it is likely that much of the creek’s flow is subsurface by the time it reaches the footbridge. This would be most pronounced during low flow periods – such as on September 3rd. Based on these observations, this study considered development of a run-of-river project on Roy’s Creek. A stream gauge was installed in October 2009 to quantify flows at Roy’s Creek and guide future investigation of this resource. 2.4 JOE’S CREEK & ERNIE’S CREEK RUN-OF-RIVER PROJECTS The 1984 Hatch reconnaissance study mentions run-of-river hydro projects at Joe’s Creek and Ernie’s Creek, but does not provide any detail on the conceptual development of these resources. The 1984 APA supplemental report dismissed development of these two creeks for the same reasons it dismissed development at Roy’s Creek. These two creeks are smaller than Roy’s Creek, but appear to be technically viable run-of-river hydro projects. This study considered developing these creeks simultaneously with Roy’s Creek, but found that this approach was not as beneficial as the other hydro projects available to the community. 2.5 MARGRET CREEK RUN-OF-RIVER PROJECT The 1979 COE study considered development of a 310-kW run-of-river project at Margret Creek, at the abandoned site of Port Althorp, about six miles south of Elfin Cove. As conceptualized by the COE study, the Margret Creek project would be a run-of-river project with a 2,600-foot long by 18-inch diameter penstock generating 310 kW of power from 270 feet of net head and a design flow of 16 cfs. Electricity would be transmitted to Elfin Cove via 6.4 miles of submarine cable and 2.0 miles of overland or overhead power line. The estimated capital cost of this project was $2.0 million (1979 dollars). Estimated annual energy output of the project is 538,000 kWh. The high cost of the transmission line alone is expected to result in this project not being economically viable compared to the other projects. For this reason, this project is not considered further in this report. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 10 0 10,000 20,000 30,000 40,000 50,000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MonthAverage kWh per MonthTOTAL SYSTEM DEMAND Option 1 - Crooked Creek ROR Option 2A - Jimʹs Lake (no dam) Option 2B - Jimʹs Lake (with dam) Option 2C - Jimʹs Lake (with Crooked Creek Power Recovery) Option 3 - Royʹs Creek ROR Option 4 - Royʹs, Ernieʹs & Joeʹs Creek 3.0 ANALYSIS OF PROJECTS Six hydroelectric project options were identified for further analysis as projects that had the potential to meet the electrical needs of Elfin Cove. The projects considered are: Project 1. Crooked Creek (stand-alone run-of-river project) Project 2a. Crooked Creek and Jim’s Lake Option A (diversion of water from Crooked Creek to Jim’s Lake and a siphon intake at Jim’s Lake for a hydro project between Jim’s Lake and tidewater) Project 2b. Crooked Creek and Jim’s Lake Option B (diversion of water from Crooked Creek to Jim’s Lake with a siphon intake and dam at Jim’s Lake for a hydro project between Jim’s Lake and tidewater) Project 2c. Crooked Creek and Jim’s Lake Option C (A run-of-river hydro project between Crooked Creek and Jim’s Lake, and a second hydro project between Jim’s Lake and tidewater) Project 3. Roy’s Creek (stand-alone run-of-river project) Project 4. Roy’s Creek, Joe’s Creek, and Ernie’s Creek (simultaneous development of run- of-river projects on all three creeks) Figure 3-1 presents the estimated average monthly electrical supply each project would provide for the community. Each of these projects is described in the following sections. The hydrology, permitting, and environmental data used to arrive at the study conclusions are presented in the Appendix. Figure 3-1: Estimated Average Monthly Energy Provided by Hydro Projects Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 11 Table 3-1: Summary of Evaluated Hydro Projects Project #1 Project #2 Project #3 Project #4 Crooked Creek and Jim’s Lake Attributes (Estimates) Crooked Creek (run-of-river) Option A (siphon only) Option B (Opt. A. with 12-foot dam) Option C (Opt. B with 2nd powerhouse) Roy’s Creek (run-of-river) Ernie’s Creek (run-of-river) Joe’s Creek (run-of-river) Combined Total for Roy’s Ernie’s and Joe’s Creeks Total Annual Energy Generation (kWh) 547,000 526,000 544,000 716,000 398,000 228,000 187,000 813,000 Displaced Diesel-Fired Energy (kWh) (percent of total demand met by hydro) 276,000 (79%) 313,000 (89%) 322,000 (92%) 344,000 (97%) 216,000 kWh (62%) N/A N/A 242,000 (69%) Net Excess Energy Available from Hydro (kWh) 196,000 138,000 147,000 299,000 107,000 kWh N/A N/A 496,000 Capital Cost (2010 dollars) $1.6 – 2.5 million $1.6 – 2.4 million $2.0 – 3.0 million $2.5 – 3.6 million $1.1 – 1.6 million $0.8 – 1.3 million $0.8 – 1.1 million $2.7 – 3.9 million Present Value of Net Savings – $460,000 to + 760,000 – $190,000 to + 830,000 – $850,000 to + 425,000 – $1,000,000 to + 440,000 + $40,000 to + 680,000 N/A N/A – $1,600,000 to – 120,000 Benefit-Cost Ratio (no excess energy usage) 0.7 to 1.0 0.8 to 1.1 0.7 to 1.0 0.6 to 0.8 0.8 to 1.2 N/A N/A 0.4 to 0.5 Benefit-Cost Ratio (with excess energy usage) 0.9 to 1.3 0.9 to 1.4 0.8 to 1.2 0.8 to 1.1 1.0 to 1.5 N/A N/A 0.7 to 1.0 Basin Area (square miles) 0.56 0.65 0.42 0.27 0.22 0.91 Average Flow (cfs) 3.0 3.7 2.5 1.6 1.3 5.4 Minimum Flow (cfs) 0.8 0.9 0.5 0.3 0.2 0.9 Conceptual Plant Design Flow (cfs) 5 9.0 4 2 ½ 2.0 N/A Intake Elevation (ft) 480 330 (1) 330(1) 480 & 330(1) 470 470 470 N/A Powerhouse Elevation (ft) 30 25 25 355 & 25 20 20 20 N/A Gross Head (ft) 450 305 305 125 & 305 450 450 450 N/A Net Head (ft) 420 280 280 115 & 280 435 435 420 N/A Minimum Power Generation (kW) 15 N/A (see note 2) 13 8 5 26 Maximum Probable Installed Capacity (kW) 120 150 150 150 + 50 = 200 100 60 50 210 Dam/Diversion Height (ft) 2 to 5 0 12 12 2 to 5 2 to 5 2 to 5 N/A Regulated Storage Height (ft) (3) N/A 8 (-8 to 0 ft) 20 (-8 to +12 ft) 20 (-8 to +12 ft) N/A N/A N/A N/A Active Volume (ac-ft) N/A 32 95 95 N/A N/A N/A N/A Pipeline Length (ft) 2,600 1,400 (diversion) 2,000 (penstock) 1,400 (diversion) 2,000 (penstock) 1,400 (upper penstock)2,000 (lower penstock) 1,300 1,600 1,200 4,100 Conceptual Pipeline Diameter (inches) 12 10 (diversion) 14 (penstock) 10 (diversion) 14 (penstock) 14 12 8 8 N/A Transmission Line Length (ft) 6,000 6,000 6,000 6,600 150 150 150 450 Communications Line Length (ft) 9,000 9,000 9,000 9,600 2,400 200 800 3,400 Access Corridors (ft) 7,500 8,200 8,200 8,200 1,400 1,700 1,300 4,400 (1) 330 feet is the estimated maximum drawdown elevation of Jim’s Lake. (2) Minimum power generation is not applicable to storage projects, as they can regulate discharge from the reservoir to match system demand. (3) The vertical datum used to describe Jim’s Lake storage is the natural surface elevation of the lake (338 feet) equals zero feet. N/A: Not applicable. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 12 3.1 COMMON PROJECT CONSIDERATIONS AND DATA This section summarizes considerations and data common to all of the hydroelectric project options investigated in this study. Considerations unique to the various projects are discussed in sections 3.2 through 3.5. 3.1.1 Hydrology Estimated stream hydrology and conceptual project design flows are based on data from ADNR’s 1984 to 1985 stream-gauging efforts and preliminary data from the current gauging efforts that began in 2008. The projects considered in this study are the largest developments considered practical at these sites based upon current information. Future analysis of these projects may find that larger or smaller projects are superior based on additional hydrology data and a more refined technical and economic analysis. Hydrology data used to develop the conceptual project design flows in this study are presented in Appendix C. 3.1.2 Geotechnical and Geomorphological Considerations The country around Elfin Cove is steep and mountainous, with bedrock often found at or near the surface. Tectonic activity and recent glaciation have created a steep terrain prone in many areas to spawning significant mass wasting events. Debris fields from avalanches, alluvial cones, and mass wasting events are common at the base of cliffs and mountain slopes. Three noteworthy mass wasting events are apparent in the project area: one in Elfin Cove that occurred after 1990, one approximately ½ mile south of Elfin Cove that occurred after 2002, and one older event near the conceptual intake site on Crooked Creek.7 Future project selection and design will consider risks associated with mass wasting hazards. At elevations below 600 feet (the area of interest for projects considered in this study), terrain exhibiting grades of approximately 40% to 100% is typically vegetated with forests dominated by large conifers. These forests typically grow in shallow soils overlaying weathered and fractured rock. Terrain with grades less than 40% appears to have thicker soil layers and a mixed conifer and deciduous forest. Terrain with grades under 30% tends to feature terraced peat bogs vegetated by grasses and a few trees. Because of the prevalence of shallow or exposed bedrock, trenching for burial of pipelines or power cables is expected to be prohibitively costly. Because of Elfin Cove’s temperate maritime climate, partial burial, on-grade, and/or above-grade pipelines are viable options for all of the hydro projects considered in this study. Similarly, on-grade or shallow burial cables are practical options for power and communications. 7 Photographs of these mass wasting events are presented in Appendix B. Event locations are indicated on the project maps in Appendix A. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 13 3.1.3 Permitting All of the projects considered in this study would fall under the jurisdiction of the Federal Energy Regulatory Commission (FERC). With the exception of projects 2b and 2c that would raise Jim’s Lake for storage, the projects considered in this study appear to meet the general eligibility criteria for exemption from the FERC licensing process. FERC exemption proceedings can be completed in as little as one year if there are no complex or controversial permitting issues. Obtaining a FERC license can take from 3 to 5 years at substantial cost. Permitting considerations are discussed in greater detail in Appendix E. 3.1.4 Environmental Considerations Field investigations and review of existing available information do not indicate any environmental conditions that are incompatible with the considered hydro projects. None of the creeks or lakes is known to be fish habitat, and no fish have been observed or reported in the course of field work. Environmental considerations are discussed in greater detail in Appendix D. 3.1.5 Land Status All of the projects considered in this study are located in the Tongass National Forest. They would all require utility and access easements across private property within Elfin Cove, and they all may have powerhouses located on state tidelands which would require tidelands leases. A project at Roy’s Creek would cross state Mental Health Trust lands within USS 2949. Land ownership is indicated on the maps of each project in Appendix A. 3.2 CROOKED CREEK RUN-OF-RIVER PROJECT A run-of-river project located on Crooked Creek would be located on U.S. Forest Service land approximately one mile south of Elfin Cove. This project would divert up to 5 cfs of the instantaneous flow in Crooked Creek to a tidewater powerhouse at Small Sandy Beach for energy generation. The project is sized at an installed capacity of 120 kW and is estimated to reduce Elfin Cove’s annual diesel fuel consumption by approximately 79%. The configuration described here is based on aerial imagery, existing mapping products, available hydrology data, differential elevation surveys to establish gross head, and field reconnaissance of the project area on foot and by air. Additional investigations would be necessary to determine resource hydrology, characterize geotechnical issues, characterize environmental considerations, and establish specific alignments and locations of project features. A map of this project is presented in Figure A-2 of Appendix A. There are technical concerns with the preferred intake site at Crooked Creek. Other aspects of this project appear technically straightforward. Construction methods would have a significant impact on the cost of this project. Conventional construction methods utilizing heavy Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 14 equipment and building access roads or trails to project sites may make this project uneconomical. The use of helicopters for material staging and manual labor for the construction, as suggested by APA in the 1984 supplemental study, appears to be a viable approach for this project. The following provides a detailed discussion of the project features. 3.2.1 Intake The existing stream-gauging station appears to be the best location along Crooked Creek for an intake structure. This intake site is in a steep-walled valley less than 100 yards wide. The valley is oriented on a southeast-northwest axis, with the creek flowing along the southerly side of the valley to the northwest. The valley floor appears to be a combination of mass wasting debris, large woody debris, and stream-borne deposits. Bedrock is not visible along the valley floor. The gauging station and proposed intake site is shown in Photographs B-2 through B-4 in Appendix B. The creek flows through a debris field consisting of large boulders. This debris field complicates access and penstock construction for an intake at this location. Crooked Creek flows at a shallow gradient of 2 to 5% in this reach. Below the gauging station, the creek descends at grades of 15 to 40%. Siting the intake downstream would sacrifice head and reduce the generation capacity of the project. Three factors at the preferred intake site on Crooked Creek are cause for concern. 1. Cliffs above the intake site appear capable of significant mass wasting events. Large boulders at the intake site and the debris field upstream of the intake site appear to be from past mass wasting events originating from these cliffs. A mass wasting event impacting the intake site could render the intake inoperable and very costly to repair. 2. The valley floor to the north of the intake site is approximately 5 to 10 feet lower than the floor where the creek is currently located. Although remnants of the 1980s stream- gauging hardware at the current gauging station/intake site suggest that this reach of the creek has been relatively stable for at least 25 years, a major flood could shift the creek to the north side of the valley, stranding the intake. A larger intake or diversion structure could be built to prevent the creek from shifting course at this location, but that would increase project costs above the estimates provided in this study. 3. The materials composing the valley floor at the intake site may render collecting water from Crooked Creek difficult. The apparent jumble of woody debris, sand, gravel, cobbles, and large boulders may have a high permeability, allowing water to flow beneath a small impoundment structure. Preventing this subsurface flow is often difficult and would increase project costs beyond the estimates provided in this study. The intake structure would use a screen or grate to keep harmful debris present in the creek from entering the penstock and damaging the turbine. Keeping these screens or grates clear could be accomplished by automated machinery or by manual labor. Cost estimates assume automated equipment to keep the intake clear of debris. Power and controls would be run in Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 15 duct parallel to the penstock from the powerhouse to the intake to run and control this apparatus. 3.2.2 Penstock A specific penstock route has not been determined for this project. The terrain that the penstock would cross does not appear to present any unusual concerns for design or construction. Future investigation of this project would further consider construction methods and materials, as these will significantly impact project costs. The methods described in APA’s 1984 supplemental study, using high-density polyethylene (HDPE) pipe, relying heavily on manual labor, and using minimal heavy equipment, appear feasible for penstock construction. 3.2.3 Powerhouse A specific powerhouse site has not been selected for this project, but the powerhouse would generally be located at Small Sandy Beach. Small Sandy Beach is a cobble and gravel beach with an approximate grade of 15%. There is a bedrock outcrop near the low tide line, and stepped rock cliffs rising about 100 feet starting about 50 feet inland from the head of the beach. The powerhouse could be located on piling in the intertidal zone or built on grade above the high water line. It would house a 120 kW turbine and generator, switchgear, controls, and associated equipment. After passing through the turbine, water would flow down the beach and into the waters of Port Althorp. 3.2.4 Power Line A specific power line route has not been determined for this project. The terrain that the power line would cross does not appear to present any unusual concerns for design or construction. An overhead line would be subject to hazards from falling trees and limbs, which would increase maintenance costs and reduce reliability. A conventional buried cable is not considered cost effective due to the presence of shallow bedrock throughout in the project area. A surface laid or shallow-burial cable in duct, as proposed in APA’s 1984 supplemental study, appears to be a favorable approach and is used to develop the cost estimates in this study. Further investigation of this project would consider construction methods and materials, as these would have a significant impact on project costs. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 16 3.3 CROOKED CREEK AND JIM’S LAKE DIVERSION AND STORAGE PROJECT A project that diverts water from Crooked Creek into Jim’s Lake and then develops the hydroelectric potential between Jim’s Lake and tidewater at Small Sandy Beach was considered in the 1984 APA supplemental study. The major differences between the run-of-river Crooked Creek project described in Section 3.2 and the combined Crooked Creek and Jim’s Lake project (hereinafter referred to as the ‘Jim’s Lake’ project(s)) are: ¾ A Jim’s Lake project sacrifices approximately 140 feet of head between Crooked Creek and Jim’s Lake. This is about 30% of the energy potential between the Crooked Creek diversion site and tidewater. Jim’s Lake Option C (described below) would recover this energy with a second powerhouse at Jim’s Lake. ¾ A Jim’s Lake project picks up an estimated additional 0.7 cfs of flow from the Jim’s Lake drainage. This is estimated to be about 15 to 30% of the available average flow at Crooked Creek. This additional flow partially offsets the lost head between Jim’s Lake and Crooked Creek. ¾ A Jim’s Lake project is able to use Jim’s Lake to store water and regulate power generation. This allows a Jim’s Lake project to follow ECUC’s loads, saving water so the project can provide more energy during droughts or cold spells than a comparable run- of-river project could. The approximate length of time that a Jim’s Lake project could supply ECUC loads under drought conditions is presented in Table 3-2. Table 3-2: Effect of Jim’s Lake Storage on Hydroelectric Generation Parameter (Estimates) Typical Summer Conditions Typical Winter Conditions Average ECUC System Load 80 kW 30 kW Project Flow 4.4 cfs 1.7 cfs Inflow to Reservoir (Drought Conditions) 0.6 cfs 0.6 cfs Reservoir Drawdown 3.8 cfs 7.6 ac-ft per day 1.1 cfs 2.1 ac-ft per day Days of Hydro Operation with Small Reservoir (32 ac-ft of storage using only siphon) 4 15 Days of Hydro Operation with Large Reservoir (95 ac-ft using siphon and a dam) 12 45 Three project configurations for this resource are considered in this study. Option A: The project originally envisioned by APA, with a diversion from Crooked Creek to Jim’s Lake and a hydro plant between Jim’s Lake and tidewater. A siphon is used to access storage in the lake. This option is described in Section 3.3.1. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 17 Option B: The same as Option A, but with a 12-foot tall dam at the Jim’s Lake outlet to maximize the lake’s storage potential. The key differences between Option A and Option B are detailed in Section 3.3.2 Option C: The same as Option B, but with a second powerhouse at the bottom of the Crooked Creek pipeline to recover the energy otherwise lost along this diversion. The key differences between Options B and Option C are detailed in Section 3.3.3 Attributes of these three project options are summarized in Table 3-1 on page 11. 3.3.1 Crooked Creek and Jim’s Lake Option A (Non-Power Diversion and Lake Siphon) In 1984, APA considered a project that diverts Crooked Creek flows into Jim’s Lake and uses a siphon intake for a hydro project between Jim’s Lake and tidewater. This same project configuration is considered here as ‘Option A’. The Option A project is sized at 150 kW and is estimated to reduce Elfin Cove’s annual diesel fuel consumption by approximately 89%. The conceptual project layout for Option A is shown in Figure A-3 in Appendix A. 3.3.1.1 Crooked Creek Diversion The Crooked Creek diversion would be located at an elevation of approximately 480 feet. The diversion would be at the same location as the intake for the Crooked Creek run-of-river project discussed in Section 3.2.1. The technical concerns regarding this site discussed in 3.2.1 also apply to the diversion structure for this project and for all three of the Jim’s Lake project options. Unlike the intake structure described in Section 3.2.1, this diversion structure would only need a coarse grate to keep large debris out of the pipeline. This grate could be cleaned manually as necessary. 3.3.1.2 Diversion Pipeline The diversion would direct up to seven cfs from Crooked Creek into a 10-inch pipeline approximately 800 to 1,400 feet long. A specific route has not been identified for this pipeline. The shorter pipeline option would discharge water into a peat bog approximately 600 feet from the lake, allowing the water to follow a natural low-gradient course into the lake (see Photograph B-5). The terrain that this pipeline would cross does not appear to present any unusual concerns for design or construction. Future investigation of this project would further consider construction methods and materials, as these would have a significant impact on project costs. The methods described in APA’s 1984 supplemental study – using HDPE pipe, relying heavily on manual labor, and using minimal heavy equipment – appears feasible for diversion pipeline construction. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 18 3.3.1.3 Jim’s Lake Intake and Penstock A siphon would be placed into Jim’s Lake allowing the project to draw the lake down eight feet below its natural level of 338 feet. This would provide approximately 32 acre-feet of storage. The siphon would extend approximately 300 feet into the lake from the outlet to reach the required depth. Water from the Jim’s Lake siphon would enter a 2,000 foot long 16-inch diameter penstock sized to handle up to nine cfs of water. A specific route has not been identified for this penstock. The size of this penstock would make construction using manual labor and hand tools challenging. The penstock would end at a powerhouse located at tidewater at Small Sandy Beach. Power and controls would be installed adjacent to the penstock from the powerhouse up to the intake siphon at Jim’s Lake. 3.3.1.4 Powerhouse The powerhouse for this project option would be similar to the powerhouse for the run-of-river Crooked Creek project as described in Section 3.2.3. It would house a 150 kW turbine and generator, switchgear, controls, and associated equipment. 3.3.1.5 Power Line The power line back to Elfin Cove would be similar to the power line described for the run-of- river Crooked Creek project in Section 3.2.4. 3.3.1.6 Access Trails This project would require approximately 8,200 feet of access trails for construction and operations. Specific access routes have not been identified. The size and type of trails necessary would depend on the design and construction methods used to build the project. 3.3.2 Crooked Creek and Jim’s Lake Option B (Option A with 12-foot Tall Dam) This option is identical to Option A, only with the addition of an approximately 12-foot tall dam at the outlet of Jim’s Lake to maximize the lake’s storage capacity. Based on the topography around Jim’s Lake, an approximately 12-foot tall dam is the maximum dam height that is considered practical. This dam would increase the available storage in Jim’s Lake from approximately 32 to 95 acre-feet, and would also increase the maximum lake level to 350 feet and the maximum project head to 330 feet. Figure A-3 in Appendix A shows the layout of the Jim’s Lake Option B project. Photographs B-6 and B-7 show Jim’s Lake and the gauging station at the lake outlet. Aside from the addition of the dam and possible trail upgrades needed to construct the dam, the infrastructure required for this project is identical to that for Option A. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 19 Increasing the amount of available storage in Jim’s Lake is estimated to further decrease the average annual ECUC diesel fuel consumption by another 3% from the Option A project configuration, for a total estimated reduction of 92% from existing conditions. In a typical year, the 32 ac-ft of storage available with just a siphon at Jim’s Lake appears sufficient to meet nearly all of ECUC’s electrical demand during the winter months. During long dry spells during the summer months, the 32 ac-ft of storage at Jim’s Lake would be drained over the course of a few weeks. Once drained, ECUC would operate its diesel generators in parallel with or instead of the hydro project. Maximizing the storage volume of Jim’s Lake with a dam would delay starting the diesels for another few weeks. This increased delay in running the diesels during summer dry spells is the typical annual benefit of maximizing the storage at Jim’s Lake under project Option B. 3.3.3 Crooked Creek and Jim’s Lake Option C (Option B with Power Recovery) This option is identical to Option B as discussed in Section 3.3.2, only with the addition of a second powerhouse to recover energy from the Crooked Creek diversion pipeline. This ‘upper’ powerhouse would be located adjacent to the Jim’s Lake reservoir shoreline and would operate as a low-head run-of-river hydro project. The additional energy generated from this upper powerhouse would reduce the volume of water that had to be released from Jim’s Lake to meet ECUC system demand. This would increase the ability of the Jim’s Lake reservoir to span summer-time droughts without needing to run the diesel generators. The addition of this second powerhouse is estimated to further decrease the average annual ECUC diesel fuel consumption by another 5% from the Option B project configuration, for a total estimated reduction of 97% from existing conditions. The configuration of the Jim’s Lake Option C project is shown on Figure A-4 in Appendix A. This project would be identical to Option B with modifications as described below. 3.3.3.1 Crooked Creek Diversion An intake structure at Crooked Creek would be similar to the structure described for the run-of- river Crooked Creek project described in Section 3.2.1. 3.3.3.2 Diversion Pipeline The diameter of the diversion pipeline would be increased to approximately 14 inches to minimize friction losses in the pipeline. 3.3.3.3 Powerhouse The second powerhouse would be located near the northerly shoreline of the raised lake at an elevation of approximately 355 feet. This upper powerhouse would house an approximately 50 kW turbine and generator, switchgear, controls and associated equipment. After passing through the turbine, water would discharge into the Jim’s Lake reservoir or onto its shores depending on the reservoir level. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 20 3.3.3.4 Power Line A power line would be installed connecting the upper powerhouse to the power line between Elfin Cove and the ‘lower’ powerhouse at tidewater. Communications would also be extended to the upper powerhouse. Power and controls would be run in conduit from the upper powerhouse at Jim’s Lake to the Crooked Creek intake. 3.3.3.5 Access An additional access trail would be extended to the upper powerhouse site. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 21 3.4 ROY’S CREEK RUN-OF-RIVER PROJECT A run-of-river project on Roy’s Creek would be located on U.S. Forest Service land east of Elfin Cove, with a powerhouse located within Elfin Cove. The configuration described here is based on aerial imagery, existing mapping products, estimated elevations of gross head, and field reconnaissance of the project area on foot. Additional investigations would be necessary to establish resource hydrology and gross head, characterize environmental considerations, and specify alignments and locations of project features. As envisioned here, this project would divert up to 4 cfs of the instantaneous flow in Roy’s Creek to a tidewater powerhouse in Elfin Cove for energy generation. The project is sized at 100 kW and is estimated to reduce Elfin Cove’s annual diesel fuel consumption by approximately 62%. This project is shown in Figure A-5 in Appendix A. All aspects of this project appear technically viable. Conventional construction methods utilizing heavy equipment are not feasible on this project due to the steep slopes present. Construction could use helicopters for material staging at the intake and manual labor for most construction activities. The detailed project features are as follows. 3.4.1 Intake An intake at Roy’s Creek would be located below the confluence of two major tributaries and above the large falls on Roy’s Creek at an elevation of approximately 350 to 450 feet above sea level. The creek in this reach flows in a shallow valley approximately 20 to 50 feet deep and oriented roughly east-west. The creek bed along this reach varies from exposed bedrock to cobbles to very large boulders, and flows along a gradient of approximately 10 to 25%. (See Photographs B-11 through B-13 in Appendix B). The north side of this valley is steeper than the south side, and rises several hundred feet above the creek to a mountain ridge. This side of the valley is generally vegetated by mature old-growth conifer forest growing directly upon thin mineral soils and broken rock. The south side of this valley is less steep and appears to have a thicker soil and organic layer. The terrain within a few hundred feet of the creek valley is vegetated by a mixed conifer and deciduous forest, alpine meadows, and peat bogs. Previous studies described flood events at Roy’s Creek that can mobilize large boulders. Observations along the creek support this conclusion. The creek is well-incised along the intake reach, and floods have scoured vegetation and soil from the valley sides to a height of five to 10 feet above the creek bed. Boulders two to four feet across are common in this reach of the creek, and these are likely to move downstream during major floods. The lower reach of Roy’s Creek, between about 30 and 100 feet above sea level, is choked with boulders of this size. An intake on Roy’s Creek would likely be constructed directly on bedrock, and would need to be designed to withstand the flood events and bed load evident at Roy’s Creek. This is possible using a helicopter to stage light equipment and material at the intake site. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 22 3.4.2 Penstock A specific penstock route has not been determined for this project. The terrain that the penstock would cross does not allow for construction of a road or the use of heavy equipment for access or construction. The penstock for this project could be partially buried, laid on the ground, or built above grade on supports. A gravity penstock installed along the south side of Roy’s Creek could likely exit the creek’s flood hazard zone within 100 feet of the intake. Once out of the creek valley, the intake would descend at a 10 to 25% grade for several hundred feet. At an elevation of about 300 feet, the penstock would begin a steep descent to tidewater at grades of 80 to 100%. 3.4.3 Powerhouse The powerhouse for this project would be located at tidewater in Elfin Cove. It could be located on piling in the inter-tidal zone or built on grade above the high water line. A specific powerhouse site has not been selected for this project, and would be located based on the penstock route and land availability. 3.5 SIMULTANEOUS DEVELOPMENT OF ROY’S, ERNIE’S AND JOE’S CREEK PROJECTS The hydroelectric resources at Ernie’s Creek and Joe’s Creek were presented in the two 1984 reconnaissance reports, but neither report discussed these resources or their development potential in detail. Both creeks are similar to Roy’s Creek, only they have smaller drainages and are therefore expected to have lower flows. Projects on these creeks are expected to be generally similar to the project at Roy’s Creek as described in Section 3.4, adjusted for lower design flows. The locations and configurations of the Ernie’s and Joe’s Creek projects are shown on Figure A- 5 in Appendix A. Because of their smaller size, these projects are expected to have higher unit costs relative to Roy’s Creek. To reduce these costs, simultaneous development of all three creeks was considered. This would allow the three projects to share certain costs such as resource and technical studies, permitting, mobilization, and construction costs. The parameters of these three projects are summarized in Table 3-1. The combined development of these creeks is only estimated to displace approximately 7% more diesel fuel than development of Roy’s Creek alone. This is due to the fact that all three of these projects are expected to have very similar hydrology, and will tend to experience the same drought and flood timing. Most of the energy from Ernie’s Creek and Joe’s Creek is available at times when Roy’s Creek is already serving the entire ECUC system load, hence they displace relatively little additional diesel fuel. This combined project configuration does provide a significant amount of excess energy, and may warrant further consideration if Elfin Cove develops a market for this energy on an interruptible service basis or if the community’s base load increases significantly. This project configuration does not warrant further consideration for reducing ECUC’s current reliance on diesel fuel for electricity generation, which is the primary focus of this reconnaissance study. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 23 4.0 ECONOMIC ANALYSIS A comparative analysis of the project alternatives considered in this study was made against projected diesel generation costs. The analysis considered the differential costs and savings associated with each hydro project compared to continued sole reliance on diesel for electrical generation. The analysis annualized capital costs on an assumed 100% debt basis, and considered annual costs for repair, operation, and maintenance of the hydro project(s) and savings from reduced fuel costs and diesel operations and maintenance costs. Costs such as ECUC’s general and administrative costs were held constant. Based on this comparison, the Crooked Creek project, Jim’s Lake projects, and Roy’s Creek project all appear cost effective. Simultaneous development of Roy’s Creek, Ernie’s Creek and Joe’s Creek does not appear to be cost effective. There is insufficient information presently available to determine which of the favorable projects is best for the community to pursue. Key assumptions used to conduct this analysis are detailed below in Table 4-1. These assumptions are discussed in greater detail in Appendix F. Economic summaries for the projects are presented in Table 4-2. Table 4-2 presents estimated electricity rates for both debt- financed and grant-financed projects. The figures in Table 4-2 have not been adjusted to reflect PCE subsidy of electric rates. Table 4-1: Assumptions Used for Economic Analysis of Hydro Projects Parameter Value Annual ECUC Electric Generation 351,000 kWh ECUC Fuel Efficiency 12.5 kWh generated per gallon Annual ECUC Fuel Usage for Electricity Generation 28,100 gallons Per Gallon Fuel Cost to ECUC (annual cost) $4.00 per gallon (2010 dollars) Total Annual ECUC Fuel Costs $112,400 (2010 dollars) Load Projections Flat growth for all analyses Project Financing Percent of Project Financed with Debt 100% Debt term 30 years Debt rate 5% Real discount rate 3% Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 24 Table 4-2: Summary of Estimated Economic Data for Evaluated Hydroelectric Projects Note 1: See Appendix F for assumptions used in the economic analysis. Note 2: Range of rates is with and without revenues from sale of excess hydro energy. Excess energy sales are calculated based on a sales rate of $0.06 per kWh for interruptible service. For a heating system with 90% efficiency, this rate is approximately equal to a fuel price of $2.80 per gallon, or a 30% discount from $4.00 per gallon fuel prices. Project #1 Project #2 Project #3 Project #4 Crooked Creek and Jim’s Lake Attribute (Estimates) Crooked Creek (run-of-river) Option A (siphon only) Option B (Opt. A. with 12-foot dam) Option C (Opt. B with 2nd powerhouse) Roy’s Creek (run-of-river) Combined Total for Roy’s Ernie’s and Joe’s Creeks Project Installed Cost $1.6 – 2.5M $1.6 – 2.4M $2.0 – 3.0M $2.5 – 3.6M $1.1 – 1.6M $2.7 – 3.9M Annual O, M, R & R Costs / Savings (50 years) $14,300 $15,300 $15,300 $17,300 $9,500 $15,700 Annual Debt Service (5% at 30 years) $96,000-156,100 $96,000-148,000 $122,000-187,000 $154,500-226,000 $63,400-96,000 $167,500-245,600 Salvage Value (at 50 years) $0 $0 $0 $0 $0 $0 Present Value of Project Costs (3% at 50 years) $2.2 – 3.4M $2.3 – 3.3M $2.8 -4.0M $3.5 – 4.9M $1.5 – 2.1M $3.7 – 5.2M Displaced Diesel Energy (kWh / year) 276,000 313,000 322,000 344,000 216,000 242,000 % of Total Energy Displaced by Hydro 79% 89% 92% 97% 62% 69% Displaced Power Plant Fuel (gallons / year) 22,100 25,000 25,800 27,400 17,300 19,400 Annual Value of Displaced Fuel ($ / year) $88,300 $100,200 $103,000 $109,400 $69,100 $77,400 Present Value of Project Benefits (ECUC’s avoided fuel costs only) (50 years) $2.3M $2.6M $2.7M $2.8M $1.8M $2.0M Benefit-Cost Ratio (not counting excess energy benefit) 0.7 – 1.0 0.8 – 1.1 0.7 - 1.0 0.6 – 0.8 0.8 – 1.2 0.4 – 0.5 Net Excess Hydro Energy (kWh / yr) 1 196,000 138,000 147,000 299,000 107,000 496,000 Displaced Heating Fuel (gallons / year) 1 5,400 3,800 4,100 8,300 3,000 13,700 Annual Value of Displaced Heating Fuel ($ / yr) $21,600 $15,200 $16,200 $33,000 $11,800 $54,700 Present Value of Project Benefits (including excess energy) (50 years) $3.0M $3.1M $3.2M $3.8M $2.1M $3.6M Benefit-Cost Ratio (counting excess energy benefit) 0.9 – 1.3 0.9 – 1.4 0.8 - 1.2 0.8 – 1.1 1.0 – 1.5 0.7 – 1.0 Estimated Electric Rate – 100% Debt Financed Hydro 2 $0.46 – 0.67 per kWh $0.44 – 0.61 per kWh $0.50 – 0.71 per kWh $0.56 – 0.81 per kWh $0.43 – 0.54 per kWh $0.65 – 0.96 per kWh Estimated Electric Rate – 100% Grant Financed Hydro 2 $0.19 – 0.22 per kWh $0.17 – 0.19 per kWh $0.15 – 0.18 per kWh $0.12 – 0.17 per kWh $0.25 – 0.27 per kWh $0.17 - 0.26 per kWh Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 25 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 REMAINING TECHNICAL CONSIDERATIONS Major remaining technical considerations are summarized below. These items should be addressed in a feasibility study of the hydroelectric resource selected by Elfin Cove for continued investigation. 5.1.1 Hydrology Collection of hydrology data necessary to complete feasibility analysis of these hydro power resources is in progress. Measurements to determine the stage-discharge curves at the three installed gauges need to be continued and a longer period of record collected and analyzed. This process is already in progress. 5.1.2 Installed Capacity This reconnaissance study considered projects at each of the hydroelectric resources that fully utilize the estimated resource potential at each site, thereby providing the greatest benefits for Elfin Cove. Once the hydrology study is completed, the optimal installed capacity of each resource should be reevaluated in the feasibility study. This will be influenced by: ¾ Community demand. A higher capacity hydro project is justified only if the community can pay for and use all or most of the energy the project produces. ¾ Resource availability. This will be determined by the hydrology study. ¾ Project cost. Many costs associated with a small hydro project are independent of installed capacity. As a result, project capacity can often be increased with a comparatively modest increase in construction or maintenance costs. 5.1.3 Existing Electric System Constraints Based on available information, ECUC’s existing electric generation and distribution systems are generally adequate to interface with a hydroelectric project. Controls at the diesel power plant would need to be modified to allow paralleling and backup capabilities with the hydro. Depending on the final size and characteristics of the preferred hydro project, different diesel gen-sets may be more efficient than the current gen-sets for paralleling with the hydro. 5.1.4 Financing The basic financing options include grants, capital financing, and debt financing. ¾ There are a variety of federal and state grant programs that could provide complete or partial funding for project construction. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 26 ¾ Capital financing would be possible if ECUC has the funds necessary to build the project out-of-pocket. If ECUC did have construction funds, it would likely require a return on its investment, which would affect the revenue structure and electric rates for the utility. ¾ Debt financing could be achieved through either private sector or public sector financing. There are state or federal financing programs such as the stateʹs Power Project Fund that could be used for project financing. Some of these programs offer below-market interest rates. There are also government loan guarantee programs that can help reduce the interest rates for debt financing. 5.1.5 Geotechnical / Topographic Considerations A topographic and geotechnical site survey is necessary to determine the specific intake location, penstock alignment, powerhouse site, and access route for the hydro project. 5.1.6 Permits All of the projects considered in this study are located on federal lands, and will require FERC licensing or FERC exemptions. There may be other unknown permitting issues - such as the presence of significant archeological resources in the project footprint - that would affect project feasibility. Resource agencies should be consulted in the feasibility phase in an effort to identify any such issues. 5.1.7 Feasibility Study Once the additional data described above is collected, a more detailed study of project feasibility is necessary. The feasibility study would focus on technical, permitting, and economic issues to confirm project feasibility and identify which of the projects considered in this study should be advanced. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 27 5.2 CONCLUSIONS This reconnaissance study has identified hydroelectric resources at Crooked Creek, Jim’s Lake, Roy’s Creek, and the smaller creeks within Elfin Cove as which development appears technically feasible. Development of the larger resources at Crooked Creek, Jim’s Lake, or Roy’s Creek offers the potential to supply a significant portion of Elfin Cove’s electrical demand. Development of the smaller resources within Elfin Cove – Joe’s Creek and Ernie’s Creek – appears technically viable, but does not warrant further study at this time because of their relatively high cost and modest benefits to the community. Projects at Crooked Creek, Jim’s Lake and Roy’s Creek warrant continued investigation because they offer the greatest potential benefits to the community and have favorable estimated benefit-cost ratios. The Elfin Cove community met in May 2010 and decided to focus on developing a project at Jim’s Lake and Crooked Creek (Option 2C as presented in this study). Based on the community’s review of this report and feedback on the findings in this report, the next step in the journey towards a community hydroelectric project is to complete a feasibility study. The feasibility study will include review of technical, environmental, regulatory, and cost considerations to assess the feasibility of the selected project. Design and permitting of the selected project can then begin after the favorable completion of the feasibility study. 5.3 DEVELOPMENT PLAN & SCHEDULE The major steps to advance the hydroelectric project are: 1. Continued maintenance of existing stream gauges at Crooked Creek and Jim’s Lake; 2. Collection of additional field data; 3. Consultation with resource agencies on key permits required for the projects; 4. Completion of a feasibility study of the projects; 5. Application for permits required for the preferred project – completion of permitting process; 6. Completion of engineering designs; 7. The securing of construction funding; and 8. Construction. Based on current information and assuming no complex resource issues emerge, any of the favorable hydroelectric projects can be ready for construction in 2013. A project schedule is presented in Figure 5-1. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT 28 Figure 5-1: Project Development Schedule 2009 2010 2011 2012 2013 ACTIVITY Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Feasibility Study Activities Hydrology Addʹl Field Investigations Agency Consultations Feasibility Study and Report Permitting FERC Licensing Resource Studies License Issuance Project Design Conceptual Design 100% Design Construction Plan Arrange Financing Construction Post Construction Activities As-Built Survey Finalize Property Documents Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX A – MAPS AND FIGURES Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT A-1 Figure A-1: Project Overview and Location Map Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT A-2 Figure A-2: Crooked Creek Run-of-River Project Map AERIAL IMAGERY DATED AUGUST 11, 1990. OBTAINED FROM ELFIN COVE FILES, COLLECTED BY USFS. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT A-3 Figure A-3: Crooked Creek-Jim’s Lake Options A and B Project Map AERIAL IMAGERY DATED AUGUST 11, 1990. OBTAINED FROM ELFIN COVE FILES, COLLECTED BY USFS. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT A-4 Figure A-4: Crooked Creek-Jim’s Lake Option C Project Map AERIAL IMAGERY DATED AUGUST 11, 1990. OBTAINED FROM ELFIN COVE FILES, COLLECTED BY USFS. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT A-5 Figure A-5: Roy’s Creek, Joe’s Creek, and Ernie’s Creek Project Map AERIAL IMAGERY BY AERO‐METRIC, INC. DATED SEPT. 4, 2002. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX B – PICTURES Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-1 Photograph B-1: Aerial View of Small Sandy Beach, Jim’s Lake, and Crooked Creek Small Sandy Beach. Proposed powerhouse site. El: 20’ Jim’s Lake El: 338’ Crooked Creek Intake/Diversion Site (behind hill) El: 480’ Mass Wasting Event (Post-2002) To Elfin Cove Aerial view of the Crooked Creek and Jim’s Lake project area. July 6, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-2 Photograph B-2: Crooked Creek Gauging Station, Looking Upstream Photograph B-3: Crooked Creek Gauging Station, Looking Downstream Photograph B-4: Crooked Creek 50 Yards Above Gauging Station, Looking Upstream Note large boulders in background (covered in vegetation). These are part of a larger boulder field (see Photograph 14) believed to be from a mass wasting event spawned from cliffs to the left in this view. Similar cliffs are adjacent to this intake site. Crooked Creek is flowing at 3.71 cfs October 9, 2009. Polarconsult. The log in the foreground is the outlet control for the pool where the stream gauge is located. Crooked Creek’s gradient increases to 15-40% below the gauging station. Crooked Creek is flowing at 3.71 cfs. October 9, 2009. Polarconsult. Crooked Creek runs at a gradient of 2% to 5% for approximately ¼ mile above the gauging station / intake site. Crooked Creek is flowing at 1.0 cfs July 8, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-3 Photograph B-5: Site for Crooked Creek Diversion Outlet or Upper Powerhouse Photograph B-6: Jim’s Lake Looking West from Lake Outlet Photograph B-7: Jim’s Lake Gauging Station Peat bog north of Jim’s Lake, looking towards the lake. If a shorter diversion pipeline was built from Crooked Creek, (Jim’s Lake Options A or B) the water would flow through these wetlands approximately 600 feet to Jim’s Lake. For Jim’s Lake Option C, the upper powerhouse would be located in this vicinity. The terrain in this photograph is at an elevation of 350 to 360 feet. The estimated maximum Jim’s Lake spillway elevation is 350 feet. September 3, 2009. Polarconsult. September 3, 2009. Polarconsult. View of Jim’s Lake looking west from outlet. July 7, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-4 Photograph B-8: Typical View of Power Line Route Between Jim’s Lake and Elfin Cove Photograph B-9: Soils Along Power Line Route Between Jim’s Lake and Elfin Cove Photograph B-10: Crooked Creek Gauging Station, Looking Upstream Typical peat bog. This peat bog is located at an elevation of about 120 to 150 feet between tidewater and Jim’s Lake. Brown areas in the foreground are normally ponds, but were dry due to a prolonged period of sunny weather. July 8, 2009. Polarconsult. This uprooted tree reveals a shallow organic soil layer overlaying mineral soil dominated by angular rocks up to approximately 12 to 18 inches in size. July 7, 2009. Polarconsult. Terrain is typically moderate slopes of less than 15% and vegetated by mature conifer forest. July 7, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-5 Photograph B-11: Roy’s Creek Running Over Bedrock Above Falls Photograph B-12: Roy’s Creek Gauging Station Photograph B-13: Roy’s Creek Waterfall Roy’s Creek running over exposed bedrock above the waterfall. Roy’s Creek runs over a combination of exposed bedrock, gravel, cobbles, and boulders for at least ¼ mile above the waterfall. September 3, 2009. Polarconsult. View of the waterfall on Roy’s Creek. The top of this waterfall is at an elevation of approximately 300 feet. Roy’s Creek is flowing at 1.06 cfs. September 3, 2009. Polarconsult. Stream gauging station at Roy’s Creek. Gauge is located in a pool with bedrock and 3- to 6-foot boulders forming the outlet control. The gauge is bolted to a 15- to 20-foot tall boulder. October 8, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT B-6 Photograph B-14: Debris Field Upstream from Crooked Creek Intake Site Photograph B-15: Debris Field in Elfin Cove Photograph B-16: Debris Field along Power Line Route This debris field is from a mass wasting event that occurred sometime after 1990. October 10, 2009. Polarconsult. This debris field extends to the proposed intake site on Crooked Creek. Polarconsult engineer Dan Hertrich, in the foreground, is sitting on a 20-foot boulder. July 8, 2009. Polarconsult. This debris field, located along the proposed power line route between Jim’s Lake and Elfin Cove, is from a mass wasting event that occurred sometime after 2002. July 7, 2009. Polarconsult. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX C – HYDROLOGY Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-1 HYDROLOGY Approximately two years of hydrology data have been collected at Crooked Creek and Jim’s Lake. Less than a year of data has been collected at Roy’s Creek. The hydrology of the identified hydroelectric resources needs to be further refined in order to more accurately estimate how much energy the resources can provide. This information is also necessary to properly design the hydroelectric project so it is not damaged by flood events. Also, hydrology information is necessary to assess the effect the project may have on the natural environment. C.1 AVAILABLE HYDROLOGY DATA Existing hydrology data is summarized in Table C-1. Flow measurements at the gauging stations near Elfin Cove are summarized in Table C-2. Hydrographs, stage-discharge curves, flow duration curves, and station notes for the three gauges are included on pages C-7 through C-13. For some of these stations, data is still preliminary as stage-discharge curves are not fully developed. Table C-1: Summary of Hydrology Data for Elfin Cove Hydroelectric Resources Location USGS Gauge ID Basin Size (sq mi) Site Elevation (ft) Latitude (DMS) 1 Longitude (DMS) 1 Begin Date End Date Number of Daily Records 2 7/6/84 2/13/85 202 Crooked Creek intake site - 0.56 480 5810ʹ40ʺ 13619ʹ16ʺ 8/22/08 Current 232 7/6/84 2/11/85 201 Jimʹs Lake outlet - 0.09 338 5810ʹ34ʺ 13619ʹ32ʺ 8/22/08 Current 310 Royʹs Creek intake site - 0.62 480 (est.) 5811ʹ29ʺ 13620ʹ03ʺ 10/9/09 Current 60 Tonalite Creek 15106980 14.5 50 5740ʹ42ʺ 13513ʹ17ʺ 6/1/68 9/30/88 7,426 1. Coordinates for U.S. Geological Survey gauges are in NAD 27. All other coordinates are in NAD 83. 2. Record count for current gauges reflects data through December 9, 2009. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-2 Table C-2: Flow Measurements for Elfin Cove Hydroelectric Resources Date Party Flow (cfs) Stage (ft) Method / Equipment Crooked Creek Intake Site (1984 to 1985) 7/6/1984 13:30 Ireland/Collazzi 0.8 0.71 Marsh McBirney 1 11/20/1984 10:15 “ 2.72 0.84 “ 3/2/1985 10:15 “ 2.29 0.7 “ 3/11/1986 11:47 “ 1.47 0.6 “ Crooked Creek Intake Site (2008 to 2010) 7/26/2008 15:15 Button/ Christensen 2.33 7.7 Pygmy Meter 2 7/27/2008 16:20 Button/ Christensen 4.35 7.76 “ 8/22/2008 14:30 Button/ Christensen 5.38 7.92 “ 6/1/2009 11:39 Button/ Christensen 4.17 7.73 “ 6/28/2009 16:40 Button/ Christensen 1.3 7.6 “ 7/9/2009 10:55 Groves/ Hertrich 0.98 7.53 Hanna Meter 3 7/9/2009 11:20 Groves/ Hertrich 0.94 7.54 “ 9/4/2009 11:40 Groves/ Glendoing 0.93 7.54 “ 10/9/2009 12:50 Groves/ Christensen 3.71 7.68 “ 12/9/2009 13:45 Button/ Christensen 1.07 7.52 “ Jim’s Lake Outlet (1984 to 1985) 7/6/1984 11:15 Ireland/Collazzi/Wild 0.23 - Marsh McBirney 11/20/1984 9:00 Ireland/Collazzi 0.93 0.57 “ 3/2/1985 9:30 Ireland/Collazzi 0.25 0.125 “ 3/11/1986 10:00 Ireland/Collazzi 0.75 0.35 “ Jim’s Lake Outlet (2008 to 2009) 7/25/2008 12:30 Button/Christensen 3.42 4.18 Pygmy Meter 7/26/2008 10:45 Button/Christensen 1.3 3.82 “ 8/22/2008 12:45 Button/Christensen 0.11 3.7 “ 6/1/2009 10:00 Button/Christensen 0.54 3.73 “ 6/28/2009 18:00 Button/Christensen 0.04 3.61 “ 7/9/2009 12:15 Groves/Hertrich 0.0911 3.56 Hanna Meter 7/9/2009 12:30 Groves/Hertrich 0.0910 3.56 “ 9/4/2009 10:00 Groves/Glendoing 0.219 3.52 “ 9/4/2009 10:15 Groves/Glendoing 0.217 3.51 “ 10/9/2009 13:45 Groves/Christensen 0.44 3.62 “ Jim’s Lake Outlet (2009 to 2010) 4 10/9/2009 14:05 Groves/Christensen 0.44 3.69 Hanna Meter 12/9/2009 14:15 Button/Christensen 0.219 3.68 “ Roy’s Creek Intake Site (2009 to 2010) 9/3/09 17:00 Groves 1.06 - Hanna Meter 10/8/2009 16:45 Groves/Christensen 2.39 1.27 “ 12/9/2009 11:45 Button/Christensen 0.66 1.09 “ 1. Current velocity stream flow method with March McBirney current velocity meter. 2. Current velocity stream flow method with Pygmy current velocity meter. 3. Sudden dose salt integration stream flow method with Hanna HI 9828 conductivity meter. 4. A small weir was installed on October 9, 2009 to stabilize and improve the section at the gauge. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-3 C.2 JIM’S LAKE BATHYMETRY The storage curve for Jim’s Lake was calculated from bathymetry data collected in July 2009. The storage curve is presented in Figure C-1. Figure C-1: Jim’s Lake Storage Curve The storage curve for Jim’s Lake was used to model reservoir status against inflows and the ECUC system load model. The reservoir model was configured to meet 100% of ECUC demands until the reservoir reached its minimum level. Inflows to the reservoir were first dispatched to meet ECUC demands. Any excess inflows were dispatched to refill the reservoir. When the reservoir is full and the hydro is meeting 100% of ECUC demand, then excess inflows and idle hydro capacity are dispatched to interruptible loads on the ECUC system. Any residual inflows are spilled. C.3 HYDROLOGY ANALYSIS The accuracy of a hydrological resource assessment is improved with a longer period of direct flow records. Several years of continuous data is ideal; however, this data is seldom available in Alaska, and it is not available in Elfin Cove. 325 330 335 340 345 350 355 0 102030405060708090100 Available Storage (ac-ft)Lake Stage (ft)NATURAL LAKE ELEVATION = 338 FEET ESTIMATED MAXIMUM PRACTICAL SPILLWAY HEIGHT = 350 FEET ESTIMATED MAXIMUM PRACTICAL DRAWDOWN = 330 FEET Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-4 When direct flow data are unavailable, another approach is to find a suitable water resource with a long period of record and similar discharge characteristics to the water resource of interest, and establish a correlation relationship between the two. The discharge characteristics of the resource of interest can then be estimated using the correlation relationship. This method requires a common period of record for the two resources to establish the correlation. USGS stream gauge #15106980 at Tonalite Creek, across from Tenakee Springs and approximately 50 miles southeast of Elfin Cove, has 20 years of flow records and is the nearest suitable candidate to Elfin Cove for this correlation approach. The correlation coefficient between Tonalite Creek and Crooked Creek for the 1984 to 1985 Crooked Creek data set is 0.64.8 For reconnaissance-level analysis, this method and correlation is adequate. Crooked Creek flows were modeled using the 20-year record at Tonalite Creek, linearly scaled using the common period of record with Crooked Creek. This Crooked Creek model was then scaled by basin area to model project flows at Roy’s Creek and the other smaller creeks within Elfin Cove. The 20-year long Tonalite Creek dataset was used to model flows and power generation at Crooked Creek, Roy’s Creek, Ernie’s Creek, and Joe’s Creek. The 1984 to 1985 flow data at the outlet of Jim’s Lake has a correlation coefficient of 0.11 with the concurrent Tonalite Creek data set. This is a very poor correlation coefficient. Because the hydroelectric projects considered for Jim’s Lake all would use the lake for storage, the instantaneous outflow from the lake is less important for hydroelectric analysis than the average outflow because the lake’s storage volume will be used to regulate discharges. Both the 1984 to 1985 and 2008 to 2009 stream gauging data indicate that outflows from Jim’s Lake outlet exceed 0.7 cfs 50% of the time. Natural outflows from Jim’s Lake are modeled as a constant 0.7 cfs for hydroelectric analysis in this study. 8 A correlation coefficient of one indicates a perfect linear relationship between the two data sets, and a correlation coefficient of zero indicates no relationship between the data sets. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-5 C.4 STREAM GAUGE STATION HISTORIES C.4.1 1984-86 Installations According to ADNR personnel, the 1984 – 1986 Crooked Creek stage data was measured with vented pressure transducers and recorded on data loggers manufactured by Bob Dryden. 9 The only data recovered from the 1984 – 1986 stream gauging efforts at Crooked Creek and Jim’s Lake was a sheaf of dot matrix printouts covering the period July 1984 through February 1985 and ADNR’s flow measurement data for both sites. The printouts include date, stage, and calculated discharge. The calculated discharges on the printouts for both gauging stations were developed using a weir equation, but the flows did not correlate well with the field measurements in the ADNR database. Because only four flow measurements are available at each site, a linear fit is used to estimate flows from the stage data for each gauging station. These data are presented in Figures C-2 and C-5 for Crooked Creek and Jim’s Lake outlet, respectively. C.4.2 Current Installations (2008 – 2009) In August 2008, ECUC installed new gauging stations in the vicinity of the original Crooked Creek and Jim’s Lake gauging stations. From August 24, 2008 through October 9, 2009, Crooked Creek and Jim’s Lake outlet stage data was measured and recorded with a sealed Hobo level logger manufactured by Onset, Inc. Atmospheric pressure fluctuations were measured with a Hobo atmospheric pressure logger (‘barologger’) installed in the immediate vicinity of the Crooked Creek gauge site. The Crooked Creek barologger was used to correct for atmospheric fluctuations at the Jim’s Lake site. The barologger experienced data quality problems during cold weather during the winter of 2008-09. Data gaps in November, December and January are due to these problems. The data gap from early February 2009 thru the end of June 2009 is due to the data logger memory being full and overwriting older records. The lack of a second barologger at Jim’s Lake outlet introduced additional noise into the stage data at this station due to transient pressure gradients (windy conditions) between the Crooked Creek and Jim’s Lake gauging stations. The gauging station at Crooked Creek is in a deep pool. The outlet of this pool is controlled by a large log lying at a slight angle to the water’s surface and nearly perpendicular to the direction of flow (See Photographs B-2 and B-3). The gauging station at Jim’s Lake outlet is about 10 feet downstream of the lake outlet in a shallow pool formed by loose rocks sitting on a weathered bedrock stream bed. After several measurements in the summer of 2009, it was determined that this section was not stable. A 9 Roy Ireland, ADNR hydrologist, personal communication. 2009. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-6 small weir was built of local materials in an effort to stabilize and improve the stage discharge curve at this location (See photographs B-6 and B-7). ECUC conducted several flow measurements at both stations during 2008 and 2009 using a pygmy current velocity meter to calibrate these gauging stations. These data, combined with additional flow measurements performed by Polarconsult and ECUC personnel in the summer and fall of 2009, are used to develop stage-discharge curves for these stations. These data are presented in Figures C-3 and C-6 for Crooked Creek and Jim’s Lake outlet, respectively. C.4.3 Current Installations (2009 – Current) On October 9, 2009, the Hobo hardware at Crooked Creek was replaced with an Acculevel vented pressure transducer manufactured by Keller America, Inc., fitted to a MONITOR data logger manufactured by Sutron, Inc. On this same date, the Hobo barologger was moved to Jim’s Lake outlet to improve atmospheric correction at this station and mounted in a large desiccant canister to improve cold weather performance. The Hobo sealed pressure transducer installed in 2008 remains in service at the Jim’s Lake outlet station. Identical Keller America, Inc. and Sutron, Inc. data logging hardware was installed at a new gauging station at an approximate elevation of 350 feet above the falls on Roy’s Creek to collect quantitative flow data for hydroelectric assessment. The Roy’s Creek gauge is located in a small plunge pool in a series of cascading falls on Roy’s Creek. The outlet control for this pool is a series of very large boulders interlocked with smaller bed materials and resting on bedrock (See Photograph B-12). Two discharge measurements have been collected at Roy’s Creek to date. This is sufficient for a preliminary stage-discharge curve, but additional flow data will be collected in 2010 to complete calibrating this station and recalibration of the Jim’s Lake outlet station. The preliminary Roy’s Creek hydrograph is presented in Figure C-8. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-7 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 7/1/84 7/29/84 8/26/84 9/23/84 10/21/84 11/18/84 12/16/84 1/13/85 2/10/85 DateStage (ʹSʹ, feet)0 1 2 3 4 5 6 7 Discharge (ʹQʹ, cfs)Recorded Stage (feet) Calculated Discharge (cfs) Linear best-fit equation for 3 DNR flow measurements: Q = 5.0711 x S - 1.4574 (R^2 = 0.9267) C.5 CROOKED CREEK HYDROLOGY DATA Figure C-2: 1984 - 1985 Crooked Creek Recorded Stage and Calculated Flow Data 1984-86 Crooked Creek Stage Discharge Curve y = 5.0711x - 1.4574 R2 = 0.9267 0 0.5 1 1.5 2 2.5 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 StageDischargeAll Flow Measurements Flow Measurements used for S-D Curve Linear (Flow Measurements used for S-D Curve) Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-8 Figure C-3: 2008 – 2009 Crooked Creek Recorded Stage and Calculated Flow Data 4.50 4.75 5.00 5.25 5.50 5.75 6.00 6.25 6.50 6.75 7.00 7.25 7.50 7.75 8.00 8.25 8.50 8.75 9.00 8/15/08 9/19/08 10/24/08 11/28/08 1/2/09 2/6/09 3/13/09 4/17/09 5/22/09 6/26/09 7/31/09 9/4/09 10/9/09 11/13/09Stage (ʹSʹ, feet)0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Discharge (ʹQʹ, cfs)Recorded Stage (feet) Calculated Discharge (cfs) Best-fit equation (7 flow measurements) Q < 5.38 cfs: Q = -24.707 S^2 + 392.87 S -1556.3 (R^2 = 0.9965) Q > 5.38 cfs: Q = 3.642 H^3.5 - 1.0275 H^2.5 +7.911 H^1.5 + 5.38 (Note 1) Note 1: Weir equation for broad crested weir with rounded section used for flows above highest measurement. H = S - 7.92 2008-10 Crooked Creek Stage-Discharge Curve y = -24.707x2 + 392.87x - 1556.3 R2 = 0.9965 0 1 2 3 4 5 6 7.5 7.55 7.6 7.65 7.7 7.75 7.8 7.85 7.9 7.95 StageDischargeAll Flow Measurements Flow Measurements Used for S-D Curve Poly. (Flow Measurements Used for S-D Curve) Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-9 Preliminary Stage-Discharge Curve for Crooked Creek 0 1 2 3 4 5 6 7 8 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percent of Time Flow is Equalled or ExceededFlow (cfs)Crooked Creek Flow Duration (2008-2009) Crooked Creek Flow Duration (1984-1985) Figure C-4: Flow Duration Curves for Crooked Creek The flow duration curves for the two Crooked Creek data sets are significantly different. This can most likely be attributed to the short period of record for both gauges. This short period of data can give a certain season (such as fall and winter in the 1984-85 data set) disproportionate weight, and can also result in unusual weather influencing the resulting hydrograph. The cause of these effects has not been investigated as part of this reconnaissance study. The 1984-85 data set was satisfactorily correlated to concurrent flow data at Tonalite Creek, and the Tonalite Creek data set, adjusted to Crooked Creek by a linear fit, is used for reconnaissance- level flow estimates for power generation. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-10 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 7/1/84 7/29/84 8/26/84 9/23/84 10/21/84 11/18/84 12/16/84 1/13/85 2/10/85 DateStage (ʹSʹ, feet)0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 Discharge (ʹQʹ, cfs)Recorded Stage (feet) Calculated Discharge (cfs) Linear best-fit equation for 3 flow measurements: Q = 1.5307 S + 0.1101 (R^2 = 0.9345) C.6 JIM’S LAKE OUTLET HYDROLOGY DATA Figure C-5: 1984 - 1985 Jim’s Lake Outlet Recorded Stage and Calculated Flow Data 1984-86 Jim's Lake Outlet Stage Discharge Curve y = 1.5307x + 0.1101 R2 = 0.9345 0 0.2 0.4 0.6 0.8 1 1.2 0 0.1 0.2 0.3 0.4 0.5 0.6 Stage All Flow Measurements Flow Measurements Used for S-D Curve Linear (Flow Measurements Used for S-D Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-11 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 5.00 8/15/08 9/19/08 10/24/08 11/28/08 1/2/09 2/6/09 3/13/09 4/17/09 5/22/09 6/26/09 7/31/09 9/4/09 10/9/09 11/13/09Stage (ʹSʹ, feet)0 1 2 3 4 5 6 7 8 9 10 Discharge (ʹQʹ, cfs)Recorded Stage (feet) Calculated Discharge (cfs) Best-Fit Equation Q(S) for 8/1/08 - 10/9/09: Q = 5.109 S^2 + 34.455 S + 58.19 (R^2 = 0.9899) Q(S) for 10/9/09 - Current: Q = (not yet developed) Figure C-6: 2008 - 2009 Jim’s Lake Outlet Recorded Stage and Calculated Flow Data 2008-09 Jim's Lake Outlet Stage Discharge Curve y = 5.109x2 - 34.455x + 58.19 R2 = 0.9899 0 0.5 1 1.5 2 2.5 3 3.5 4 3.43.53.63.73.83.9 4 4.14.24.3 StageDischargeAll 2008-09 Flow Measurements 2009-2010 Flow Measurements Flow Measurements Used for S-D Curve Poly. (Flow Measurements Used for S-D Curve) Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-12 Preliminary Stage-Discharge Curve for Jim ʹs Lake Outlet 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percent of Time Flow is Equalled or ExceededFlow (cfs)Jimʹs Lake Flow Duration (2008-2009) Jimʹs Lake Flow Duration (1984-1985) Figure C-7: Flow Duration Curves for Jim’s Lake Outlet The flow duration curves for the two Jim’s Lake outlet data sets are significantly different. As for the Crooked Creek data sets, this can most likely be attributed to the short period of record for both gauges. This short period of data can give a certain season (such as fall and winter in the 1984-85 data set) disproportionate weight, and can also result in unusual weather influencing the resulting hydrograph. Another potential cause for the discrepancy in the Jim’s Lake outlet data is the stage-discharge curves applied to the different data sets. Because stage-discharge curves are typically a power function over a sufficiently large range of flows, the use of a linear fit for the 1984-85 data will tend to underestimate higher flows, which is consistent with the observed discrepancy. This matter has not been explored to resolution as part of the reconnaissance study. Both datasets exhibit a 50% flow exceedance value of approximately 0.7 cfs. This flow is within the range of field measurements for both periods of record, so both models can be expected to be reasonably accurate at a flow of 0.7 cfs. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT C-13 -2.50 -2.00 -1.50 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 10/8/09 10/15/09 10/22/09 10/29/09 11/5/09 11/12/09 11/19/09 11/26/09 12/3/09 12/10/09Stage (ʹSʹ, feet)0 2 4 6 8 10 12 14 16 18 20 22 24 Discharge (ʹQʹ, cfs)Recorded Stage (feet) Calculated Discharge (cfs) Best-Fit Equation Q = 9.611 S - 9.8161 (preliminary) C.7 ROY’S CREEK HYDROLOGY DATA Figure C-8: 2009 Roy’s Creek Recorded Stage and Calculated Flow Data 2009-10 Roy's Creek Stage Discharge Curve (Preliminary) 0 0.5 1 1.5 2 2.5 3 1.05 1.1 1.15 1.2 1.25 1.3 StageDischarge Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX D – ENVIRONMENTAL CONSIDERATIONS Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT D-1 D.1 THREATENED AND ENDANGERED SPECIES The U.S. Fish and Wildlife Service’s online consultation guide indicates that there are no species listed as threatened or endangered within the vicinity of the projects. 10 D.2 FISHERIES AND WILDLIFE Development of the recommended project has the potential to affect fisheries and wildlife resources. Significant effects to wildlife are considered unlikely. The Alaska Department of Fish and Game (ADFG)ʹs Atlas of Waters Important for the Spawning, Rearing or Migration of Anadromous Fishes does not indicate that Crooked Creek, Jim’s Lake, Roy’s Creek or the other small streams in Elfin Cove are habitat for anadromous species. Existing information and field reconnaissance have not identified fish in any of the project waters. The steep stream gradients and waterfalls present on all of the streams investigated in this study are almost certainly barriers to fish passage. D.3 WATER AND AIR QUALITY None of the projects would have any significant negative impacts on water or air quality. By reducing diesel combustion within Elfin Cove, all of the projects would improve air quality. D.4 WETLAND AND PROTECTED AREAS All of the projects will require filling wetlands areas, such as for the diversion structure located in the creek. Some of the penstock or access routes for the various projects could also cross wetlands. If Jim’s Lake is used for storage, that entire water body would be affected. D.5 ARCHAEOLOGICAL AND HISTORICAL RESOURCES None known. The state historical preservation office would be consulted to determine if any historical or cultural resources are present in the project area. D.6 LAND DEVELOPMENT CONSIDERATIONS None. D.7 TELECOMMUNICATIONS AND AVIATION CONSIDERATIONS The project will not affect telecommunications or aviation. 10 http://alaska.fws.gov/fisheries/endangered/pdf/consultation_guide/70_consult_guide_map_11x17.pdf Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT D-2 D.8 VISUAL AND AESTHETIC RESOURCES Due to the dense conifer vegetation present around Elfin Cove, none of the projects would have a large visual impact. Most of the disturbed areas, such as transmission, access, and penstock alignments, would be mostly concealed from view from sea or the air. Tidewater powerhouses at Small Sandy Beach (for the Jim’s Lake projects) would be visible from sea and air. These would be small structures consistent with the many isolated outbuildings found at tidewater throughout Southeast Alaska, and they could be finished in materials and colors that would blend with their surroundings. Tidewater powerhouses within Elfin Cove (for Roy’s Creek or the smaller in-cove resources) would be visible from throughout the community, but would not be distinct from the many other buildings present within the community. A project on Roy’s Creek would reduce the amount of water flowing over the waterfall that is located at an elevation of about 300 feet. Depending on the size of this project, these falls would be mostly or completely dewatered for a significant portion of the time. Similarly, development of the other small creeks within Elfin Cove would also dewater any water features downstream of the diversion points on these streams. D.9 MITIGATION MEASURES No impacts warranting mitigation are known at this time. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX E – PERMITTING INFORMATION Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT E-1 E.1 FEDERAL PERMITS E.1.1 Federal Energy Regulatory Commission The Federal Energy Regulatory Commission (FERC) has jurisdiction over hydroelectric projects that meet certain criteria. One of these criteria is whether the project would occupy federal land. All of the projects considered in this study are located in whole or part within the Tongass National Forest, and therefore would fall under FERC jurisdiction. For projects that require a FERC license, all state and federal permitting efforts are managed through the FERC licensing process. Small hydroelectric projects meeting certain criteria can be exempted from FERC licensing requirements, in which case the normal state and federal licensing processes must be used. The main eligibility criteria for exemption from FERC licensing are: ¾ The project must use a ‘natural water feature’. All of the run-of-river projects considered in this study are expected to qualify under this criteria. It is unclear if FERC would accept a siphon at Jim’s Lake under the ‘natural water feature’ rule. A dam at Jim’s Lake would not qualify. ¾ The project owner must have control over all non-federal project lands. This would include private lands and state lands (tidelands) that the projects may occupy. Private lands could be secured by easements or leases, and state tidelands could be secured with leases as well. E.1.2 U.S. Forest Service All of the projects considered in this study are located in whole or part within the Tongass National Forest, and would require land leases and permits from the U.S. Forest Service for the specific development proposal(s). E.1.3 U.S. Army Corps of Engineers Permits The diversion structures and tailraces of all the projects considered in this study would be located within wetlands, therefore a wetlands permit from the COE will be required. Other project features, such as access, transmission, and penstock routes may also be located in wetlands. With the exception of projects that use Jim’s Lake, these projects would likely be eligible for a Nationwide Permit #17 for small hydroelectric development. A project at Jim’s Lake may require an individual permit from the COE. If any of the projects use a powerhouse built on piling in tidelands or other permanent tidelands structures, additional COE permits will be required under the COE’s marine navigation authority. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT E-2 E.1.4 U.S. Environmental Protection Agency A stormwater pollution prevention plan will be required for construction of the projects considered in this study. E.1.5 Federal Aviation Administration None of the projects considered in this study would have any features likely to present a hazard to aviation. E.2 STATE OF ALASKA PERMITS E.2.1 Alaska Department of Natural Resources Permits E.2.1.1 Coastal Zone Consistency Review All of the projects considered in this study are located within the state’s coastal zone, and will have to go through consistency review by ADNR’s Division of Coastal and Ocean Management for consistency with the statewide coastal management plan. The projects are not located within a local coastal management program. E.2.1.2 Land Authorizations A project on Roy’s Creek would require an easement on and possibly a lease of State of Alaska Mental Health Trust land. E.2.1.3 Tidelands Permits If any of the projects included temporary or permanent structures within state tidelands, tidelands permits may be required. E.2.1.4 Material Sale Agreement Not applicable. E.2.1.5 Water Use Permit / Water Rights Any of the projects would need to obtain water rights from the ADNR. E.2.2 Alaska Department of Fish and Game Permits E.2.2.1 Fish Habitat Permit Any of the projects would need to obtain either a fish habitat permit or a finding that a permit is not required from the ADFG. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT E-3 E.2.3 Alaska Department of Transportation Permits Not applicable. E.2.4 Alaska Department of Environmental Conservation (ADEC) Permits E.2.4.1 ADEC Wastewater or Potable Water Permits Not applicable. E.2.4.2 Solid Waste Disposal Permit Not applicable. E.2.4.3 Air Quality Permit & Bulk Fuel Permit Not applicable. E.3 LOCAL PERMITS The project is not located within an organized borough or city, so no local permits would be required. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT APPENDIX F – ASSUMPTIONS FOR ECONOMIC ANALYSIS Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT F-1 ECONOMIC ANALYSIS ASSUMPTIONS F.1 ESTIMATED ANNUAL PROJECT COSTS F.1.1 General, Administrative, Operation and Maintenance Expenses Typical general and administrative costs for a utility like ECUC range from $20,000 to $40,000 per year. This annual expense includes activities such as meter reading, customer service, managing the utility’s business affairs, etc. These costs will not change if the means of energy generation changes from diesel to hydroelectric or a combination. Typical non-fuel operation and maintenance (O&M) expenses for a utility like ECUC are about $20,000 per year. This annual expense includes the costs of lube oils, filters, and other consumables for the diesel generators, maintenance labor, and similar costs that are related to the running time of the diesel engines. A significant portion of these costs will be avoided with any of the recommended hydroelectric projects. The hydroelectric projects will have additional operation and maintenance costs. This includes additional labor costs for monitoring and maintaining the hydro as well as direct expenses for parts and consumables. Based on experience with similar projects, annual O&M costs for Roy’s Creek are estimated to be $11,400 annually. Costs for other configurations are higher. The Crooked Creek and Jim’s Lake options would have higher transmission line, penstock, and trail maintenance costs. There would also be more travel time and reduced project reliability due to the greater distance to these projects. Any of the three Jim’s Lake projects would have two intake structures to maintain, and the Jim’s Lake project Option C would have two powerhouses to maintain. F.1.2 Repair and Replacement Most of the hydroelectric project systems and components have a very long useful life. The intake, penstock, powerhouse, switchgear, turbine/generator, and power line all are expected to have useful lives of 30 years. Some portions of the project will require periodic repair or replacement. Some minor components, such as minor pumps, actuators, control sensors, and similar devices, are assumed to have a useful life of five years. The water turbine would need an overhaul after about 15 to 25 years. The average annual expense for repair and replacement is estimated at $4,300 for Roy’s Creek. As for O&M costs, more complex and more distant project configurations have higher repair and replacement costs. F.1.3 Taxes No tax liability is considered. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT F-2 F.1.4 Insurance It is assumed that the ECUC’s existing insurance policies would be adequate for the hydroelectric project. No additional annual costs are allocated for insurance. F.1.5 Financing The costs of financing will depend on how the project is financed. Commercial finance for the project is assumed to consist of a 30-year debt at a nominal interest rate of 5%. Adjusted for inflation (assumed at 3% average over 30 years), this is a real interest rate of approximately 2%. In addition, the cost of originating the debt is assumed to be 3% of the debt amount (for items such as application fees, loan guarantee fees, origination fees, etc). F.2 ESTIMATED PROJECT REVENUES AND SAVINGS F.2.1 Direct Fuel Displacement All of the hydro projects would significantly reduce (62% to 97%) the amount of diesel fuel ECUC consumes for electricity generation. Fuel savings are based on a diesel plant efficiency of 13.0 kWh per gallon, and a fuel price of $4.00 per gallon. F.2.2 Excess Energy In addition to reducing diesel fuel usage at the power plant, the hydroelectric projects also generate a significant amount of excess energy that is available to the community. For economic analysis purposes, 10% of the gross excess energy is assumed to be consumed by the hydro load governor system and/or station service, and 90% is assumed to be made available to utility customer loads such as space heating and water heating applications. Of this 90%, 12% is assumed to be consumed by losses on ECUC’s distribution system. The balance (79% of gross excess energy generation) can be metered to ECUC’s accounts on an interruptible basis at a special rate. All of this excess energy is assumed to be directed to space and water heating applications, displacing heating oil that is consumed with an assumed average efficiency of 70%. Because the community building and shop currently receive waste heat from the power plant, 75,000 kWh of the excess energy is assumed to be allocated to these buildings at no cost in all economic analyses. F.2.3 Environmental Attributes As small, low-impact, hydroelectric projects, all of these hydro projects would have the ability to market their environmental attributes nation-wide. The market for environmental attributes is still developing, and as a result is subject to considerable uncertainty. There is federal and state legislation pending that could influence this market, transforming it from the existing Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT F-3 patchwork of state compliance markets and national and regional voluntary markets into a more uniform and regulated national market. A reasonable range for the value of the environmental attributes from this project is $0.001 to 0.020 per kWh on the voluntary market. Elfin Cove has the potential to market its unique Alaska setting to command a premium for its environmental attributes. For the economic analysis, no revenue from sale of environmental attributes is assumed. F.2.4 Indirect and Non-Monetary Benefits The studied hydroelectric projects offer significant indirect and non-monetary benefits in addition to direct economic benefits. These other benefits include: ¾ Reduced air pollution (NOx, SOx, particulates, and hydrocarbons) due to decreased operation of the diesel power plant ¾ Reduced noise when the diesel plant is turned off. ¾ Reduced risk of oil spills due to decreased throughput and handling of fuel. ¾ More stable energy prices. With a hydro, ECUC’s electricity rates will be largely insulated from increasingly volatile world oil prices. ¾ Secondary benefits arising from the availability of plentiful hydroelectity with a stable price. This will increase the affordability of living and doing business in Elfin Cove and will increase the long-term viability of the community. Secondary benefits could include an increase in the population of school-age children, ensuring that school enrollment exceeds district and state thresholds for state funding year-to-year. ¾ Economic multipliers due to the fact that a greater percentage of the utilityʹs revenues will be retained in the local community for labor instead of paying external entities such as fuel suppliers. Local training and experience with small hydroelectric projects. To the extent that locals choose to be involved in construction, maintenance, and operation of the hydroelectric project, they will learn a unique set of skills. These skills will become increasingly useful as Alaska continues to develop local hydroelectric resources. Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT G-1 APPENDIX G – EXCERPT FROM COMMUNITY MEETING MINUTES MAY 28, 2010 Non-Profit Community of Elfin Cove Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. JUNE 2010 – FINAL REPORT G-2 Community of Elfin Cove Non-Profit Corporation Board Meeting Minutes May 28, 2010, 7:00 p.m. Call to Order: Members present: David Abel, Jim Wild, Patti Lewis, Gordy Wrobel, Shirley Perkins, Lane Ply, Karen Nemacek Board Members Present: Susan Abel, Dennis Meier, Joe Kulavik, Travis Lewis, Mike Nelson, Steve Alexander, Debbie Hemenway Dennis Meier presiding; Susan Abel, Secretary Agenda Item 2. Hydropower Decision- Mike Nelson moved that Elfin Cove select Hydropower Option #2C. Travis Lewis seconded it. Board Member Vote: Mike Nelson: yes; Steve Alexander: yes; Joe Kulavik: yes; Travis Lewis: yes; Debbie Hemenway: yes; Dennis Meier: yes; Susan Abel: yes.