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HomeMy WebLinkAboutNAHP_Stakeholder Info INFORMATION DOCUMENT Nushagak Area Hydroelectric Project Lake Elva and Grant Lake Projects near: Dillingham, Alaska Prepared By: Nushagak Electric and Telephone Cooperative 557 Kenny Wren Rd PO Box 350 Dillingham, Alaska 99575 907-842-5251 tel. 907-842-2780 fax www.nushtel.com April, 2009 2 INTRODUCTION AND BACKGROUND Nushagak Electric & Telephone Cooperative, Inc., (“NETC”), is evaluating a multiple- development hydroelectric Project, the Nushagak Area Hydroelectric Project (“NAHP”, “Project”), as described in this document. (Note that the Project was called the “Dillingham Area Hydroelectric Project”, or DAHP, in earlier documents). The NAHP would consist of the Grant Lake and Lake Elva hydroelectric projects (“Projects”, “Grant Lake Project”, “Lake Elva Project”). Both Projects and portions of their transmission systems would be located in Wood-Tikchick State Park administered by the State of Alaska Department of Natural Resources (ADNR). The proposed 1.5 megawatt (MW) installed capacity Lake Elva Project would be located 36 miles north by northwest of Dillingham, Alaska. The proposed 2.7 MW Grant Lake Project would be located 43 miles north of Dillingham. The purpose of the Projects would be to displace costs of diesel fuel electrical generation which is currently NETC’s only generation alternative. The Grant Lake Project electrical generation would meet NETC’s current base load and would equal the average generation of NETC’s diesel power plant. Lake Elva Project generation would meet existing NETC’s peak loads. BACKGROUND and NEED for PROJECT NETC’s electrical generation is entirely petroleum-based, consisting of 7 diesel generators with an installed capacity of 6.84 MW. Costs for diesel fuel, at 2008 levels, corresponded to NETC electrical rates of about $0.46 per kilowatt hour, among the highest in Alaska. Continued dependence on diesel as the sole electrical generating source has exposed the area’s commercial and residential users to high costs and unstable pricing. In 2008, NETC revived feasibility studies done in 1980 and 1981 (see page 12) of the NAHP with the intention of developing renewable energy resources to address these issues. In this document, NETC describes the 1) the proposed NAHP Projects, and 2) the proposed process and schedule for completing feasibility studies and applying for necessary permits for Project construction and long-term operation. CONTACT WITH NETC Interested parties are encouraged to contact NETC for information on this development. The name, business address, phone number and email of the person authorized to act as agent for NETC is: Frank Corbin, CEO / General Manager Nushagak Electric & Telephone Cooperative, Inc., dba Nushagak Cooperative 557 Kenny Wren Road Post Office Box 350 Dillingham, AK, 99576 3 907-842-6315, Phone 907-842-2780 Fax fcorbin@nushagak.coop PRELIMINARY FEASIBILITY STUDY and REPORT In 2008, NETC contracted EES Consultants of Kirkland, WA, to conduct a preliminary feasibility study for the overall NAHP proposal as conceived at the time. The pre-feasibility study was intended to update earlier evaluations of the project, in terms of today’s fuel, materials and construction costs. The final report “Review of Dillingham Area Hydro Project” was submitted in February, 2009, and is referenced in this document as the “EES Report”. DESCRIPTIONS of the PROJECTS In the following sections, English measurement units are used in all descriptions. Elevations are in feet above mean low sea level and are denoted “El”. The EES Report examined both storage and run of river configurations for each Project. The four configurations described were: • Lake Elva, Run of River; • Lake Elva, Storage; • Grant Lake, Run of River; and • Grant Lake, Storage. PROJECT LOCATIONS The proposed location of the Projects would be: The Lake Elva Project intake would be located in Sections 1, 2, 7, 11, 12, of Township 6-7S, Range 58W of the Seward Meridian. The approximate Lake Elva Project powerhouse location would be: WGS 1984 - longitude 159 degrees 03’ 52” west; latitude, 059 degrees 35’ 07” north. The Grant Lake Project intake would be located in Sections 28, 29, 32, 33, of Township 4S, Range 54-55W of the Seward Meridian. The approximate Grant Lake Project powerhouse location would be: WGS 1984 - longitude 158 degrees 35’ 60” west; latitude, 059 degrees 47’ 12.5” north. LAKE ELVA PROJECT The Lake Elva Project would be located approximately 36 linear miles north of Dillingham, Alaska, on Lake Elva and Elva Creek (Figure 2). Elva Creek drains into Lake Nerka, which is in Wood-Tikchick State Park, a component of the State of Alaska state park system. 4 Two primary alternatives exist for Lake Elva Project configuration: the Storage Alternative and the Run of River Alternative, as described below (Figure 1): Lake Elva Project Run of River Alternative In this project configuration, a 10-foot high diversion dam would be constructed at the outlet of Lake Elva to allow the withdrawal of water through an intake structure (Figure 1). Water would be conveyed through a 10,800 foot long penstock to the powerhouse housing a single 1500 kW installed capacity turbine (Table 1). The powerhouse would be located approximately 2,600 feet upstream from Elva Creek’s confluence with Lake Nerka. A temporary construction staging area is proposed near the powerhouse. Operated in run of the river mode, this alternative would offer only a small amount of storage (about 2500 acre-feet) for short-term flow regulation. Flows below the powerhouse would be only slightly modified from the natural hydrology. Table 1. Lake Elva Run of River Project Features and Dimensions. Spillway Elevation El 313 Minimum Reservoir Elevation El 305 Usable Storage 2500 Powerhouse Floor Elevation El 79 Penstock Length (ft) 10,800 Penstock Diameter (in) 48 Installed Capacity (kW) 1500 Lake Elva Storage Project Alternative Under this alternative, an approximately 100-ft high earth fill dam would be constructed about 1.0 mi downstream of Lake Elva (See Figure 1). From the dam, a 6700-ft penstock would convey water to a powerhouse housing a 1000 kW generator (Table 2). The powerhouse location would be the same as for the Run of River alternative. Under this configuration, flows below the powerhouse would be those necessary to optimize generation, but could be to some extent regulated for instream purposes. 5 Figure 1. Lake Elva Project, Storage and Run of River Alternatives. 6 Table 2. Lake Elva Storage Project Features and Dimensions. Spillway Elevation El 370 Minimum Reservoir Elevation El 320 Usable Storage (af) 26,800 Powerhouse Floor Elevation El 79 Penstock Length (ft) 6700 Penstock Diameter (in) 42 Installed Capacity (kW) 1000 Lake Elva Project Access Construction access to the staging area during summer would be via barge across Lake Aleknagik and Lake Nerka. Once at the Lake Elva construction site, access would be via a short access road to the staging area and an approximately 1.7 mi-long road along the penstock route to the damsite. In winter, equipment, materials, and supplies would be moved to the construction sites for either alternative over the ice of Lake Aleknagik and Lake Nerka. Access for maintenance during summer would be by float plane or small boat. During winter, the project could be accessed via ski plane, snow machine or other over-ice vehicles. GRANT LAKE PROJECT As with the Lake Elva Project, two primary alternatives are being examined for the Grant Lake Project: the Storage Alternative and the Run of River Alternative, as described below (Figure 2): Both Grant Lake Project alternatives would be located approximately 43 linear miles north of Dillingham, Alaska, on Grant Lake and Grant River (Figure 2). Grant River drains into Lake Kulik, which is in Wood-Tikchick State Park, a component of the State of Alaska State Park system. Grant Lake Run of River Project Alternative In this project configuration, an approximately 5-ft high diversion dam would be constructed at the outlet of the Grant Lake. (Figure 2). An approximately one-mile long diversion canal would be excavated approximately one mile north of the dam with an invert at El 468 (Table 3). The canal would extend to a rock fill dike and intake 0.8 miles north-northwest of the dam . Water would be withdrawn through the dike into a 5-foot diameter, 6,600-foot long pipe transitioning through a surge tank to a 48-inch diameter, 3,100-foot long steel penstock to the powerhouse at El 240. The powerhouse, located approximately 5.3 mi upstream from Grant Creek’s confluence with Lake Kulik, would house a 3000 kW generator. A small amount of storage would be available for regulation (10,000 acre-feet) of flows by manipulating the height of the lake. With this project configuration, flows downstream of the powerhouse would be only slightly modified from the natural hydrology. 7 Table 3. Grant Lake Run of River Project Features and Dimensions. Spillway Elevation El 481 Minimum Reservoir Elevation El 476 Usable Storage (af) 10,000 Powerhouse Floor Elevation El 240 Penstock Length (ft) 8400 Penstock Diameter (in) 66 Installed Capacity (kW) 3000 Grant Lake Storage Project Alternative Under this alternative, a 20 ft. high dam would be constructed at the outlet of Grant Lake (See Figure 2). A canal would be constructed in the same location as for the Run of River Alternative, and an intake installed in the diversion dam at that location. Water would be conveyed through an 8,400 ft long penstock from the intake to the powerhouse with one Turgo type turbine of about 1.7 MW installed capacity. Powerhouse locations for the Run of River and Storage alternatives would be the same. Under this alternative, flows below the powerhouse would be regulated to provide nearly constant flow. The turbine would only operated at best efficiency in order to maximize generation. Table 4. Grant Lake Storage Project Features and Dimensions. Spillway Elevation El 500 Minimum Reservoir Elevation El 478 Usable Storage (af) 52,500 Powerhouse Floor Elevation (af) 240 Penstock Length (af) 8400 Penstock Diameter (in) 60 Installed Capacity (kW) 1700 8 Figure 2. Grant Lake Project, Storage and Run of River Alternatives. 9 Grant Lake Project Access Construction access for either Grant Lake Project alternative would be via barge or small boat across Lake Aleknagik and Lake Kulik. Access could also be via a road paralleling the proposed primary transmission route (see below). During winter, access would be over the ice of Lake Aleknagik and Lake Kulik. Summer access for routine maintenance would be by float plane or small boat. Winter access would be via ski plane or various ice vehicles. LAKE ELVA, GRANT LAKE PROJECT OPERATIONS In the EES Report, operations of the run of river and storage alternatives for both Projects were simplified to provide a basis for comparison. Under the run of river alternatives, flows in stream reaches between the Project intake and powerhouse (the “bypassed reaches”) were assumed to be 1 cubic foot per second (cfs). Below the powerhouses, flows were assumed to be essentially the natural flow of the stream in question, composed of either powerhouse discharge or powerhouse discharge plus spill. For the storage alternatives, bypassed reach discharge were assumed to be 1 cfs, and discharges downstream of the powerhouse were assumed to be the result of flow regulation to optimize output, resulting in reduced flow variation relative to natural conditions. Streamflow regimes in both bypassed reaches and those below the respective powerhouses will be the subject of extensive consultation during further Project development. TRANSMISSION FACILITIES The primary transmission alternatives utilize either overhead, underground or submarine transmission facilities to minimize aesthetic effects of structures within Wood-Tikchick State Park (Figure 3). Under all routing alternatives for both Projects, the existing 7.2 kilovolt (kV) distribution line between Dillingham and Aleknagik would be upgraded to 34.5 kV and a new substation would be constructed about 5 mi north of Aleknagik. In this document, the terminology for the various transmission routes has been simplified from that used in the EES Report and referenced to known features or locations. We expect to use this terminology instead of the EES Report terminology in the future. Transmission routes from the two Projects are described below (Figure 3), as described below: Lake Elva Project Transmission Routes Two primary transmission routes are being evaluated for the Lake Elva Project, the Lower and Upper Lake Nerka Transmission routes (See Figure 3). 10 Figure 3. Grant Lake and Lake Elva Projects Transmission Line Alternatives. 11 Lower Lake Nerka Transmission Route In the Lower Lake Nerka Route, the first leg of the transmission line would be routed approximately 24 mi to the south southwest from the Lake Elva Project powerhouse, to a point at the northwest limit of the mountain range directly west of Snake Lake adjacent to Mable Mountain. At this point, two routing alternatives are being considered: 1) The Snake Lake Transmission Route, (named because of the popular local name for Lake Nunavaugaluk), on whose east shore this route would travel; and 2) the Lake Aleknagik South Shore Transmission Route, which would follow the south shore of Lake Aleknagik approximately 12 miles to the town of Aleknagik. Under the Snake Lake routing, the line would pass in a southeast direction along Snake Lake’s eastern shore then turn east and join the upgraded line between Dillingham and Aleknagik. The Lake Aleknagik South Shore Transmission Route would continue on the west shore of Lake Aleknagik and join the upgraded Dillingham-Aleknagik line at the existing substation in Aleknagik. Under both of these routings, the line would be either underground or overhead, depending on terrain and visual factors. Also under consideration is a submarine routing beneath Lake Aleknagik (the Lake Aleknagik Transmission Route), in which the line would be routed underwater from the northwest corner of Lake Aleknagik to the existing substation in Aleknagik (See Figure 3). Upper Lake Nerka Transmission Route Under this routing alternative, the transmission line would be routed underwater beneath Upper Lake Nerka to the eastern end of Upper Lake Nerka (See Figure 3). At the end of the lake, the line would emerge from the water and be routed either underground or overhead (depending again on terrain and/or visual factors) to join with the Grant Lake Transmission Route (described below). Grant Lake Project Transmission Route The proposed Grant Lake Project Transmission Route would be southeast from the Grant Lake Project powerhouse through about 8 miles of new underground transmission to the border of Wood-Tikchick State Park. From that point, the line would proceed in underground and/or overhead segments outside the Park border to the south and then southwest for about 35 miles to Aleknagik (See Figure 3). PERMITTING and CERTIFICATION PROCESSES In 2008, NETC requested that the Federal Energy Regulatory Commission (FERC) in Washington D.C. determine whether the Projects would be jurisdictional under FERC Regulations. Jurisdictional hydropower projects in the U.S. must receive a license from FERC authorizing construction and operation under a set of FERC and state and federal resource agency conditions. 12 To be deemed non-jurisdictional, projects must not: • Be located on a navigable water of the United States; • Occupy lands of the United States; • Utilize surplus water or waterpower from a government dam; and • Be located on a body of water over which Congress has Commerce Clause jurisdiction. NETC applied for jurisdictional determination for the two Projects in 2008. In response, FERC sent a determination that both projects were non-jurisdictional under FERC regulations. Under this determination, NETC must still meet requirements of all applicable state and federal statutes and regulations, including issuance of permits authorizing construction and operation and demonstration that the project would be consistent with existing plans and other standards. Each of the permits and certifications is expected to contain conditions under which construction and operation may proceed. NETC will conduct a meeting with appropriate permitting and certification agencies in the spring of 2009 to develop a process for moving forward in the absence of FERC licensing requirements. DESCRIPTION OF STUDIES TO DETERMINE THE FEASIBILITY OF THE PROJECT Nushagak Cooperative proposes to conduct several studies to determine overall NAHP Project feasibility as well as feasibility of the individual Projects. The exact extent and nature of these studies cannot be known until completion of early stage consultation with Alaska state and Federal resource agencies, and results of more detailed engineering calculations. Reconnaissance level studies of the Grant Lake and Lake Elva Projects are included in the Reconnaissance Study of the Lake Elva and other Hydroelectric Power Potentials in the Dillingham Area prepared for the Alaska Power Authority by Robert W. Retherford Associates in February, 1980, and in the Lake Elva Project Detailed Feasibility Analysis completed in 1981 by R. W. Beck and Associates, Inc. It was the purpose of the EES preliminary feasibility study to expand upon information in these older studies and to preliminarily propose steps toward more detailed analysis and selection of preferred alternatives. NETC proposes to continue with studies in all areas in association with consultation with Alaska state and federal resource agencies to determine more exact design and operation specifications to carry through the permitting and certification processes. ECONOMIC and ENGINEERING FEASIBILITY EVALUATION Hydrology. Hydrology data will be retrieved or generated to obtain applicable data on Elva Creek and Grant River streamflows, if available, and lake levels in Lake Elva and Grant Lake. Generation and Transmission. A detailed generation study will be performed to determine the exact size and type of turbine/generator and switchgear. Once transmission alternatives have 13 been evaluated and initial route selections made, NETC will further evaluate buried/overhead/submarine routings, associated equipment and materials, and costs. Engineering Feasibility. Engineering feasibility studies will be performed in association with field surveys and more detailed topographic mapping (to include LIDAR mapping) to determine the constructability of the various project features in relation to subsurface conditions, vegetation and topography. Economic Feasibility. After preliminary selection of generation alternatives, detailed generation studies will help determine energy generation potential under a range of meteorological conditions. Energy study results will be used in association with power sales, construction, maintenance and operations costs to determine the economic feasibility of the selected alternatives. ENVIRONMENTAL STUDIES The exact nature and scale of environmental studies will be determined during agency consultation and study planning. Generally, however, environmental field and/or office studies are required to meet information needs in the following areas: • Aquatic Resources • Terrestrial Resources • Water Use and Quality • Geology and Soils • Socioeconomics • Cultural Resources • Land Use and Recreation • Aesthetics NETC proposes to conduct a formal study planning process among appropriate Alaska state and federal resource agencies in the Spring of 2009. NETC will conduct a technical meeting to present the current project proposal and obtain input on studies which would begin in 2009. The study planning process would result in timeframes for the various resource-related studies, to support a schedule for the permitting/certification phase of the Project development. DISTURBANCES from CONDUCTING STUDIES Disturbances from conducting studies would be minimal. The only expected disturbance could arise if extensive additional geotechnical work were required, but previous studies in this area should preclude such a need. All onsite work will be coordinated with the appropriate Tribes and state and federal resource agencies. Also, permanent or semi-permanent stream gaging stations would require installation of structures which, depending on approved design, might be visible from lakes and streams. 14 SCHEDULE for STUDY COMPLETION, PERMITTING AND CERTIFICATION NETC proposes to conduct engineering feasibility studies, at a higher level of detail than in the EES Report, during the second half of 2009, with the objective of developing a preliminary design in late 2009 or early 2010. Also included in this design effort would be results from resource agency consultation which might bear on project generating and transmission facility features, locations and visual attributes. By spring, 2010, NETC would have developed a design suitable for inclusion in a Coastal Project Questionnaire (CPQ) submitted to ADNR. The CPQ would trigger involvement of all other permitting and certification agencies. The permitting and certification process would likely result in further design, construction and operation refinements which would serve as the basis for conditions in the final permits and certifications.