Loading...
HomeMy WebLinkAbout5.1.1C MEMO-2014-12-11-SE Alaska Yukon TL technical memo-5140420 Morrison Hershfield | Suite 202, 208 Main Street, Whitehorse, YT Y1A 2A9, Canada | Tel 867 456 4747 Fax 867 456 4760 | morrisonhershfield.com Technical Feasibility Memorandum – Viability Analysis of Southeast Alaska and Yukon Economic Development Corridor Whitehorse, Yukon Presented to: Department of Energy, Mines and Resources Yukon Government Alaska Energy Authority State of Alaska Project No. 5140420 December 11, 2014 M:\PROJ\5140420\10 DESIGN\TECHNICAL MEMO\MEMO10-2014-12-11-SE ALASKA YUKON TL TECHNICAL MEMO_FKP-5140420.DOCX Prepared in Association With: Morrison Hershfield | Suite 202, 208 Main Street, Whitehorse, YT Y1A 2A9, Canada | Tel 867 456 4747 Fax 867 456 4760 | morrisonhershfield.com December 11, 2014 Ryan Hennessey, Utilities Specialist Energy Solutions Centre, Energy Mines and Resources Government of Yukon, Box 2703 Whitehorse, Yukon, Y1A 2C6 Dear Mr. Hennessey: Re: Technical Feasibility Memorandum for Viability Analysis of Southeast Alaska and Yukon Economic Development Corridor Morrison Hershfield is pleased to provide the above noted technical memorandum. This memorandum represents the concluding deliverable of the Technical Feasibility Scenarios task for this study. It builds upon the work conducted and decisions made at the Development Scenario workshop held on June 18th, 2014. In summary, the technical work to date indicates that a transmission line between Skagway Alaska and Whitehorse Yukon is technically viable. As specified in the project’s Terms of Reference, this current memorandum only addresses the technical aspects of the study and does not present cost estimates. Capital and operating costs will be addressed in the subsequent Financial Feasibility task. I trust that this deliverable meets your expectations and we looking forward to continuing to advance this interesting initiative with the Government of Yukon and State of Alaska. Yours truly, Morrison Hershfield Limited Forest Pearson, P.Eng., Geological Engineer M:\PROJ\5140420\10 DESIGN\TECHNICAL MEMO\L-HENNESSEY-2014-12-11-TECH MEMO COVER_FKP-5140420.DOCX TABLE OF CONTENTS Page 1. INTRODUCTION 1 1.1 Project Rationale 1 1.2 Background and Setting 1 1.3 Report Organization 1 2. DEVELOPMENT SCENARIOS 3 2.1 Workshop Summary 3 2.2 Preliminary Technical Considerations 4 2.3 Other Economic Opportunities in the Whitehorse-Skagway Corridor 5 2.4 Two Development Scenarios 6 3. TECHNICAL FEASIBILITY OF TRANSMISSION INTERCONNECTION 8 3.1 System Interconnection Study 8 3.2 Technical Considerations for Transmission Route 10 3.3 Transmission Line Terminus 11 3.4 Terrain Conditions 13 3.5 Route Description 16 3.6 Transmission Line Design 21 4. REVIEW OF WEST CREEK HYDRO POTENTIAL 30 4.1 Background and Context 30 4.2 Hydrology and Power Studies 31 4.3 Review of Site Development Layouts 36 4.4 Review of Environmental and Regulatory Issues Associated with West Creek Hydro Development 40 5. REFERENCES 43 TABLE OF CONTENTS (Continued) Page APPENDICES APPENDIX A: Transmission Line Concept Route Maps APPENDIX B: Development Scenarios Workshop Report APPENDIX C: Skagway-Whitehorse Interconnection System Analysis APPENDIX D: Transmission Line Design Criteria APPENDIX E: West Creek Hydro Technical Review LIST OF TABLES Table 1: Summary of Transmission Conceptual Alignment Options 21 Table 2: Anticipated Allowable Spans for Double-Pole H-Frame Structures – White Pass to Carcross23 Table 3: Anticipated Allowable Spans for Double-Pole H-Frame Structures – Carcross to Whitehorse24 Table 4: Anticipated Allowable Spans for Single-Pole Wishbone Structures – Option B Carcross to Whitehorse 25 Table 5: Estimated Weights of Steel Y-Pole Towers 27 Table 6: Anticipated Spans for Steel Y-Pole Structures (Low to Moderate Avalanche Risk) 27 Table 7: Minimum Right of Way Widths for Structures 28 Table 8: Summary of Structure Type, by Route Segment 29 Table 9: Average Monthly Flows on West Creek at Dam Site 31 Table 10: Average Monthly Power Production; Calculated based on 1963-1977 Flows 34 LIST OF FIGURES Figure 1. Study Overview Map 2 Figure 2. Simplified schematic of the proposed transmission interconnection. 8 Figure 3: Double Pole H-Frame Structures White Pass to Carcross: a) with and b) without Fibre Under-build 24 Figure 4: Double-Pole H-Frame Structures Carcross to Whitehorse: (a) with, and (b) without Fibre Under-build 25 Figure 5. Wishbone Structures: (a) with, and (b) without Fibre Under-build 26 Figure 6: Steel Y-Pole Structures between White Pass and Carcross 27 Figure 7: Average Monthly Flows on West Creek at Dam Site 32 Figure 8: Average Monthly Energy with 25 MW Installed Capacity 34 Figure 9: Energy Generation by Year; based on 1963-1977 Flow 35 - 1 - 1. INTRODUCTION 1.1 PROJECT RATIONALE The Yukon-Southeast Alaska Economic Development Corridor concept has been developed through collaboration between the State of Alaska and the Government of Yukon. The purpose of the Study is to explore the economic and technical feasibility of linking the respective power grids, and to provide improvements in the telecommunications systems. The focus of this Study is to examine feasibility of a transmission connection, and to identify the most viable scenario that represents the greatest net benefit to both governments. See Figure 1 for an overview of the study extents. 1.2 BACKGROUND AND SETTING Common to both Alaska and Yukon is a desire to develop renewable energy sources and reduce reliance on (and costs) generating with fossil fuels such as diesel and natural gas. Presently, electricity is provided to communities in the upper Lynn Canal region, including Skagway, from both hydro and diesel generation sources. The demand for electricity in Skagway is highest during the summer when tourism peaks and thousands of cruise ship passengers visit the area. While docked in Skagway, the ships generate their own power, primarily using diesel, as there is no shore-side electricity available. The cruise ships were found to be the largest contributor to local air pollution in a study done in 2010, and investigations are now underway to see what hydroelectric opportunities are available to supply this need. The potential West Creek hydro project is located at Dyea, near Skagway Alaska. A hydro project at this site could be capable of supplying the needs of both Skagway and Haines, including the cruise ship industry during the summer. In Yukon, existing hydro generation is incapable of supplying all of the winter energy demand, and fossil fuel generation is relied upon to provide additional energy when it is required. Although demand for electricity is predicted to grow in Yukon, currently there is some surplus hydro capacity during the summer. The opportunity exists, therefore, to match the seasonal supply of energy (from West Creek and Whitehorse) to future electrical demand in both Yukon and Southeast Alaska (specifically Skagway and the upper Lynn Canal area). 1.3 REPORT ORGANIZATION This report describes the technical feasibility of the transmission intertie project, and includes a review of the power potential of West Creek hydro. In addition, the report includes a summary of the two “development scenarios” (the Scenarios) that were identified during a multi-stakeholder workshop in June 2014. These scenarios set out the specific combinations of demand forecast and supply options that are considered in evaluation of the economic feasibility of the transmission intertie, and represent the basis for the preliminary cost estimates used in the technical analysis. For detailed discussion of the scenario workshop and its conclusions, refer to Appendix A. #Y #Y #Y #Y #Y #Y #Y#Y #Y WESTCREEK YUKON BRITISH COLUMBIA ALASKA CHILKOOT TRAILNATIONALHISTORICSITE GLACIER BAY NATIONAL PARK AND RESERVE TAKHINI SUBSTATION ALASKA H IG HWAY SOUTHK L ONDIKE HIG H WAYSOUTHKLONDIKEHIGHWAYMARSH LA K E T A G I S H L A K EBENNETTLAKEW E ST A R M T AGI S HLAKETAKUARMFISHLAKEKUSAWALAKEKasida y a Creek ATLINL A KEFRASER HYDRO( 0.25 MW ) WHITEHORSE RAPIDS GENERATINGSTATION ( 40 MW ) FISH LAKE HYDRO( 0.6-1.3 MW ) GOAT LAKE( 4 MW ) DEWEY LAKES HYDRO( 0.9 MWC ) 10 MILE HYDRO( 0.6 MW ) ATLIN HYDRO( 2.1MW ) LUTAK HYDRO( 0.25 MW ) KASIDAYA CREEK( 3 MW ) Skagway Haines Atlin Carcross Whitehorse Sources: Esri, HERE, DeLorme, TomTom, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo,MapmyIndia, © OpenStreetMap contributors, and the GIS User Community 450000 450000 500000 500000 550000 5500006550000 655000066000006600000665000066500006700000670000067500006750000² Topographic data was obtained from http://server.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map on December 4, 2014 This drawing has been prepared for the use of Access Mining Consultants Ltd.'s client and may not be used, reproduced or relied upon by third parties, except as agreed by Access Mining Consultants Ltd. and its client, as required by law or for use of governmental reviewing agencies. AccessMining Consultants Ltd. accepts no responsibility, and denies any liability whatsoever, to any party that modifies this drawing without Access Mining Consultants Ltd.'s express written consent. DECEMBER 2014 D:\Project\AllProjects\Proposals\Whitehorse-Skagway_Transmission_Line\Figure1_20141205_11x17.mxd STUDY OVERVIEW MAP FIGURE 1 SOUTHEAST ALASKA AND YUKON ECONOMIC DEVELOPMENT CORRIDOR 0 10 20 30 Kilometers #Y Existing HydropowerFacilities (capacity in MW) Conceptual TransmissionLine Corridor Exisitng 138 kVTransmission Existing <138 kVTransmission Towns Highway Railroad Yukon First NationSettlement Lands National Parks andReserves 1:675,000 WHEN PRINTED ON 11 BY 17 INCH PAPER - 3 - 2. DEVELOPMENT SCENARIOS The Development Scenarios were the primary topic of discussion at a workshop held on June 18th, 2014. Note that these Development Scenarios, as described below, were discussed in the context of a number of initial assumptions and considerations about route options, design criteria for the transmission line, generation capability of West Creek hydro, and so forth. The technical work that has now been completed and is discussed in Sections 3 and 4 of this report, has either confirmed, or in some instances modified the earlier assumptions that were made in the following Development Scenarios. 2.1 WORKSHOP SUMMARY The workshop focused on identifying up to three development scenarios for the Southeast Alaska and Yukon Economic Development Corridor Study (the “Study”). These scenarios are ones that could potentially provide long term benefits to both Yukon and Alaska in terms of seasonal supply of renewable energy. Other benefits could include improved telecommunication reliability and capability. The workshop was held in Whitehorse, Yukon and included representatives from both Alaska and Yukon. Materials were prepared to facilitate discussion at the workshop and were distributed to workshop participants; these materials are found in Appendix B, including: Workshop Background Papers o Background Paper #1 – Long Term Fossil Fuel Generation Requirement Scenarios o Background Paper #2 – Supply Options o Background Paper #3 – Initial Transmission Corridor Cost Estimate o Background Paper #4 – Alaska-Yukon Fibre Optic Corridor Link Preliminary Development Scenarios [as reviewed at June 18 workshop] o Summary description o Detailed description Other Workshop Materials o Assessment of Simulated West Creek Generation o Map of Southeast Alaska and Yukon Economic Development Corridor In order to assess the viability of a transmission interconnection between Whitehorse and Skagway/SE Alaska, the Study must consider specific conditions (loads, system reliability, other potential uses of the corridor such as telecommunications link) that would be required to make development of an electrical interconnection work. - 4 - 2.2 PRELIMINARY TECHNICAL CONSIDERATIONS The transmission line would be designed to transmit approximately 25 MW of electricity from Alaska to Yukon (and vice versa) with a 138 kV line voltage. Previous work considered a 69 kV line; however, this lower voltage line is unlikely to provide any material capital cost savings relative to 138 kV. Furthermore, a 69 kV line would limit capability and the ability to integrate with the Yukon’s existing 138 kV transmission grid. A 138 kV line would facilitate system stability which is of critical importance when moving small loads over long distances between two relatively small electrical systems. Whether an AC or DC1 transmission connection should be considered was discussed. It was suggested that a DC link might enhance stability (it would be operated as an isolated section of the transmission system) and avoid inter-jurisdictional regulatory requirements that otherwise must consider the effects of a system connection on system stability. A DC transmission connection, however, would incur greater initial costs compared to the AC option and could also preclude connections to other projects (generation IPPs or loads/customers) along the length of the DC line. It was noted that there is a need (separate from this Study) to clarify the regulatory implications of an AC connection in Yukon and Alaska. This may include gathering more information regarding the federal regulatory and legal implications pertaining to export of electricity from both Canada and the United States. Use of ATCO Electric Yukon’s existing 34.5 kV line extending from Carcross to Whitehorse was considered but this concept was rejected for the following reasons: The existing 34.5kV line does not have the capacity to transmit 25 MW of power. The current line has the capacity to transmit on the order of 17 MW and the existing load in Carcross is about 4 MW. Transforming the voltage from 138 kV to 34.5 kV at Carcross would require an additional substation (estimated at approximate cost of $8-10 million). A 138 kV line voltage can be accommodated at the Riverside substation in Whitehorse without adding significant new equipment and transformer(s); this would save $8-10 million in substation upgrading costs. The key technical considerations relating to the Project that were discussed at the workshop included: Using the existing Riverside substation (in Riverdale) as the terminus for the new 138 kV line would avoid the need for a new substation in Whitehorse. Several possible locations for a new substation in Skagway exist; none of the existing substations would accommodate a new 138 kV line without significant upgrade. The voltage of a new transmission line would need to be 138 kV to transmit a load of 20-25 MW. · Line would be mostly constructed of wood poles, with steel structures used in more challenging terrain and through avalanche zones. 1 AC refers to alternating current and is currently used in the transmission grid; DC refers to direct current - 5 - Preliminary considerations concerning route options for the transmission line included: Routes for a line between Skagway and Whitehorse were previously studied, and identified a preferred route along the Klondike Highway, and a less desirable route following the White Pass railway ROW (due to poor road access and viewscapes). Three route options to be considered between Carcross and Whitehorse: a) a new ROW following the Klondike Highway b) Use of the existing ATCO Electric ROW (re-building on the existing 34.5kV line); c) a new ROW following the White Pass and Yukon Railway. A fourth option was also discussed that would continue east from Carcross along the Tagish Road as far as Jakes Corner, and then north to Whitehorse adjacent to the Alaska Highway. Workshop participants confirmed that this option should be noted, but given the longer distance (and therefore higher costs), it would not be assessed at this time. While the Carcross-Jakes-Whitehorse option is longer, and thus more costly, it is an option for future consideration in the context of improved system reliability and other potential hydro/transmission developments in the southern lakes region, such as the Atlin Hydro Expansion (Pine Creek Hydro). Future studies of this project should re-assess synergistic opportunities considering a Jakes Corner alignment. 2.3 OTHER ECONOMIC OPPORTUNITIES IN THE WHITEHORSE-SKAGWAY CORRIDOR The Study will also consider potential synergies between development of the transmission line and a new fibre optic link between Whitehorse and Skagway. The following was noted: If the timing of the two projects were coordinated, significant cost savings related to stringing the fibre optic line along the transmission line could be realized (as compared to burying the fibre optic cable in its own designated easement). If the timing of the two projects could not be coordinated (and the fibre optic link proceeded independently and ahead of the transmission line) there are still potential positive synergies related to securing concurrent easements and rights of way for both projects. The workshop broadly discussed the economic development corridor between Southeast Alaska and Whitehorse, and examined other economic development opportunities besides the transmission and fibre optic link. It was noted that highway and rail elements of this corridor have existed for over a century, providing year-round transportation linkages between Whitehorse and Southeast Alaska (and at one time an oil pipeline also paralleled the same right-of-way). The workshop participants concluded that at this time, there are no tangible specific market opportunities to be assessed such as a new pipeline connection or any other elements beyond the transmission line and fibre optic cable. In addition, it was acknowledge that there are other hydropower opportunities in the region. However, there are no projects that have been proposed at this time and therefore they not included in the scope of this analysis. It was noted that the viability assessment report should include a high-level discussion around the scope (and what was not included) of this “economic development corridor”. - 6 - 2.4 TWO DEVELOPMENT SCENARIOS The following two development scenarios represent the findings of the Workshop. These scenarios will form the basis for the viability assessment. Scenario 1 – Development of transmission line with West Creek hydro generation This scenario is focused on development of the transmission corridor that would supply surplus power to Whitehorse from the proposed West Creek Hydro project near Skagway, displacing growing thermal generation (diesel & LNG) on the Yukon grid in the winter. In other words, there needs to be an electrical demand in the Yukon for additional renewable energy. In summary, Scenario 1 assumes the following: Potential generation from West Creek hydro estimated at 134 GWh/year Potential summer Cruise Ship Load estimated at up to 30 GWh/Year in Skagway Potential surplus power from West Creek hydro would meet Yukon’s projected winter load requirements of 54 GWh/Year (see Appendix B for details). Scenario 1 - Development with West Creek Hydro Generation Whitehorse, Yukon Skagway, Alaska Need sufficient fossil fuel displacement opportunity Confirm West Creek Hydro volumes, timing and costs Financial & Economics viability issues (beyond timing):Financial & Economics viability issues (beyond timing): Expected cost savings from fossil fuel displacement Net power charges to cruise ships & sustainability of loads Competitive renewable cost options (e.g., other hydro sites)Overall capital costs for new hydro & transmission Supply security & charges for delivered West Creek hydro Financing, ownership and cost recovery arrangements About 54 GW.h/yr from Alaska to Yukon New loads needed on grid of 25-50 GW.h/yr to proceed within next decade About 134 GWh/yr generation, less 80 GW.h/yr June to Nov (not needed in Yukon) - 7 - Scenario 2 – Development of transmission line without West Creek hydro, with Yukon Energy (YEC) summer hydro surplus supplying Skagway cruise ship loads This development scenario is focused on development of the transmission corridor well in advance of any new hydropower projects in the Upper Lynn Canal area (such as West Creek) being developed. The transmission corridor would be developed to transmit surplus summer power from Whitehorse to Skagway to displace cruise ship diesel generation loads as soon as shore power is available in Skagway and Haines. In summary: Potential surplus generation of 34 to 38 GWh/year is available in Yukon from early June to end of September2. Concerns were noted that surplus hydro capacity (MW) is only between 4 to 15 MW, yet cruise ship capacity requirements are 25 MW or more. YEC LNG generation could be considered as backup supply, subject to pricing arrangements. Scenario 2, with its lower transmission loads relative to Scenario 1, would not enable recovery of the full annual cost of the transmission line under normal financing arrangements. This scenario would likely require some level of government funding support. Therefore the ultimate viability of the project would presume either a future Scenario 1, (i.e. develop West Creek hydro) or some other renewable supply would be developed in proximity to the transmission line to supply power to the Yukon. 2 Yukon load forecasts indicate that by 2018, summer surplus hydro (without new mine loads) ranges from 34 to 38 GWh, with average weekly surplus ranging from 4 to 15 MW over the summer period. Any new mining loads would reduce this summer surplus Scenario 2 - Development with YEC Summer Hydro Surplus & Skagway Cruise Ship Loads Whitehorse, Yukon Skagway, Alaska Surplus Hydro (early June through September)Energy for Cruise Ships (early May through September) Financial & Economics viability issues (beyond timing):Financial & Economics viability issues (beyond timing): Charges for hydro power supplies Diesel cost saved by ships Charges for LNG back up generation Shore power connection costs Factors that reduce hydro surplus Factors that limit cruise ship diesel displacement volumes Upper limit on viable transmission charges Competitive cost option (LNG generation at Skagway) Assume up to about 34-38 GW.h surplus summer hydro with current generation & loads - need LNG backup About from 30 GW.h per season with peak load 6.5 to 32.5 MW in different weeks over the period About 30 GW.h/yr from Yukon to Alaska - 8 - 3. TECHNICAL FEASIBILITY OF TRANSMISSION INTERCONNECTION 3.1 SYSTEM INTERCONNECTION STUDY One of the key components of this technical review was to assess the technical feasibility of the proposed interconnection between the electrical system in the Skagway –Haines area and the electrical system in the Yukon. In November 2014, a study was undertaken by Mr. S. Boutillier (consultant to YEC) to examine the technical implications of connecting the Yukon and Skagway electrical grids and the associated electrical requirements if the project proceeds (see Appendix C). This study was reviewed by Electric Power Systems (EPS), and confirmed that the study findings are reasonable for a feasibility study. The study is summarized below. The proposed interconnection is based on expected economic benefits due to energy transfers between the two systems, and based on expected improvements in reliability of the two systems. The interconnection will also facilitate supplying shore power at Skagway when cruise ships are present, combined with the construction of the West Creek hydro facility. Figure 2. Simplified schematic of the proposed transmission interconnection. - 9 - The intent of the study was to identify the technical feasibility of the interconnection of the two electrical systems. Specifically, the study assessed the normal and emergency operation of the interconnected system. Whenever the conditions(normal or emergency) within the two systems was unacceptable, the study tried to identify any additional equipment or modifications to existing equipment, that would be necessary to make the interconnected system work properly. In essence the study purpose was to identify any critical flaws that would impact the overall economic viability of the proposed interconnection, and recommend any changes or adjustments that should be considered to facilitate the successful development of the project. The assessment confirmed that the interconnection would be capable of transferring up to 25MW of power in both directions with suitable facilities included in the development. The technical study was focused on voltage and frequency response of the system while interconnected and during separation events (ie. if one part of the system experiences an outages, what is the effect on the other parts of the system?) Voltage and frequency are the two dominant characteristics of an electrical system that directly indicate reliability and robustness of the system. When the voltage or frequency deviates from normal, system controls attempt to restore the voltage and/or frequency back within acceptable limits, via automatic controls. The study investigated the voltage and frequency for the expected range of different system conditions, including light and heavy load conditions, summer and winter conditions, and energy transfer conditions in both directions along the proposed interconnection. The study identified the need for additional equipment to control voltage, including under-load tap changing transformers, reactive compensation along the proposed line, and possible tuning of generator excitation systems. The study also identified some issues associated with the frequency response of the system, during emergency or contingency conditions. These items included tuning of the under-frequency based load shedding (UFLS) relays, and tuning of generator controls (governors). The study also assessed the ability of the interconnected system to accept a transfer of power from the grid to the cruise ships in a controlled manner. EPS reviewed the study and confirmed that the approach used throughout the study was appropriate, and the issues of voltage and frequency control are appropriate and are in line with typical expectations for isolated electrical systems of this size. With respect to voltage control, the use of reactive compensation is as expected and is reasonable. With respect to frequency control, the load shedding design should be re-evaluated based on the interconnection and coordination for joined operations. The use of generator tripping and/or braking resistors during over-frequency conditions is reasonable and appears to be commonplace within the Yukon Energy system. However, generator tripping is not as common within the Alaskan system, including the systems in Southeast Alaska. The use of braking resistors should be evaluated in detail during a follow-up system impact study for the proposed facilities. As an alternative to the braking resistor used in this study, the design of the West Creek hydro facility should investigate over frequency control measures in its design. The load ramping assessment that looked at transferring cruise ship loads off ship generators and on to the grid, seems reasonable. Experience throughout Alaska indicates that the ramp rates evaluated in the study can be easily met under controlled conditions, and may be easily increased. - 10 - In general, the conclusions of the study are reasonable for a feasibility study. As mentioned in the report, additional items will need further study as the design of the facilities proceeds. Given the low capacity of the system, the significant transmission exposure and the lack of redundancy on the system, several aspects of the design of the transmission interconnection require particular attention as the project proceeds. Testing of some of the existing equipment is also necessary to refine the simulation models. This is required so that more precise evaluations can be made for the interconnection and for any additional equipment necessary to support the interconnection. The objective will be to ensure that the system reliability is acceptable, economies are realized, and operational coordination is achieved. 3.2 TECHNICAL CONSIDERATIONS FOR TRANSMISSION ROUTE The purpose of the route identification is to determine at least one technically feasible route for a transmission line between Skagway Alaska and Whitehorse Yukon. Route selection for the transmission line was based upon examination of a variety of mapping sources available for the area, including: National Topographic Database 1:50,000 map series (Yukon) Terrain Resource Information Management (TRIM) 1:20,000 topographic base maps (BC) US Geological Survey 1:25,000 topographical mapping (from National Geographic, 2010) Alaska land tenure data from State of Alaska Department of National Resources Alaska Mapper GeoEye 50cm multispectral satellite imagery for southern lakes region Yukon (provided by Geomatics Yukon). Image dates June 24 2009, July 8 2009, September 14 2009, June 21 2010, July 30 2010. Canada Lands Digital Cadastral; Data for Yukon (from Canada Lands Survey Natural Resources Canada) Yukon land tenure datasets (License and land notations), Geomatics Yukon BC Land Tenure from DataBC including: TANTALIS Crown Tenures, Crown Land Rights-of- way, Surveyed Parcels and Surveyed Right-of-way Parcels. ATCO Electric Yukon electrical distribution system drawing for Southern Lakes (provided by ATCO Electric Yukon) Klondike Highway Avalanche Atlas (prepared for Yukon Department of Community and Transportation Services 1986) and Klondike Highway Avalanche Control Study (prepared for State of Alaska 1987) In addition to the above, field observation of the route along the South Klondike highway route was completed on June 17th, 2014. Discussions were also held with the current manager of the avalanche control program on the south Klondike Highway3 to confirm areas of avalanche terrain as identified in the 1986 Avalanche Atlas. 3Pers. Comm. Colin Mackenzie, May 21, 2014 - 11 - The identification of a feasible route considered the following technical elements: Proximity to existing linear corridors (i.e. transmission lines, highways, railway, pipeline easements) Risk posed by avalanches (through the Alaska, White Pass and Tutshi Lake portions of the corridor) Terrain (steepness, bedrock, water bodies, constructability) Access for construction and maintenance Land tenure Viewscapes Based on the information obtained, conceptual route option(s) were identified and mapped as shown on the route map series found in Appendix A. These options should be considered as preliminary routes, as the identification of a preferred route will require in-depth analysis of the terrain, land tenure, and discussions with utilities, landowners, municipalities, and other primary stakeholders along the route. These route options formed the basis for a preliminary cost estimate for a transmission line, and the context and assumptions that were used in the technical and economic feasibility analysis of the corridor concept. The route options are described in Section 3.5. In broad terms, there is one route option between Skagway and the US/Canada border that parallels the Klondike Highway. From the border to Carcross, there is generally one route option, again following along the highway. A short segment of alternative route through the Canadian portion of the White Pass area has been identified that would be less visible from the highway and could be considered in this scenic area. From Carcross to Whitehorse, three route options are identified, two of which would require new rights-of-way, and a third option that would utilize the existing ATCO Electric right-of-way. 3.3 TRANSMISSION LINE TERMINUS The line would run between Skagway and Whitehorse, with one substation at each end. The new line would connect the existing electrical systems in Skagway and Whitehorse. In addition, the Skagway terminus would connect a new power line from the West Creek hydro facility to the transmission line between Skagway and Whitehorse. 3.3.1 Skagway Terminus The proposed terminus of the transmission line in Skagway is located at the junction of the Dyea Road and Klondike Highway, as shown in Appendix A, on Map 1. A new substation would be required at this location as currently there is no existing substation in the vicinity of Skagway that could accommodate a new high voltage transmission line. There is adequate space available at the proposed substation location. Land ownership in the vicinity of the proposed substation location consists of Municipal lands (Skagway), Mental Health Trust lands, and State lands. In the event that the West Creek hydro site is developed, it was assumed that a new 34.5kV power line would be constructed between West Creek hydro and a new substation at Skagway. Power generated at West Creek would be distributed to Skagway (to supply cruise ships in summer) as well - 12 - as to Whitehorse in the winter. The power line between West Creek hydro and the substation at Skagway, or any new power line into Skagway to serve the cruise ships, is assumed to be the responsibility of local utilities. The technical and financial feasibility of such lines are not within the scope of this study and would be included to those specific projects. 3.3.2 Whitehorse Terminus Two options for the terminus of the transmission line in Whitehorse were initially reviewed, namely: 1. the existing Yukon Energy substation at Riverside, which is located in Riverdale on the east side of the Yukon River directly opposite Yukon Energy’s hydro generating station, and 2. the existing Yukon Energy Takhini substation located north of Whitehorse, approximately 8 km north of the junction of the Alaska Highway and the North Klondike Highway. The Riverside substation is the preferred terminus for the new transmission line, for the following reasons: Riverside has sufficient space to accommodate a new 138 kV transmission line connection There is no need for a new transformer at this substation; existing transformers will accommodate a new 138kV line The transmission line would be approximately 25 km shorter, and therefore less expensive, than a line extending through Whitehorse and north to the Takhini substation. The existing transmission line that crosses the Yukon River may need to be reconfigured to accommodate the new transmission crossing between the Yukon Energy yard and Riverside substation. Upgrading and some new equipment (e.g. breakers) would be required at this substation. As noted above, the Takhini Substation option would require a longer transmission line than terminating the line at Riverside. As such, this option would incur additional costs for the line to extend another 25 km to the north, than if the line terminates at the Riverside substation. Routing the line through the built up areas along the Alaska Highway through Whitehorse would be challenging. The Takhini substation would require a new transformer to accommodate Riverside Substation Photo 1. Whitehorse Rapids Generating Station and Riverside Substation (photo courtesy Yukon Energy Corporation) - 13 - the new 138kV line. Given the above considerations, the Riverside substation represents the preferred northern terminus for the transmission line. Having confirmed the location of the terminus in Whitehorse, route option(s) into the Riverside substation could be identified and analyzed. 3.4 TERRAIN CONDITIONS The economic development corridor and conceptual transmission line alignment runs from the Lynn Canal in Southeast Alaska to Whitehorse, Yukon. The Lynn Canal is a steep sided fjord in the Coast Range. From there the route traverses the Boundary Ranges of the Coast Mountains via the White Pass. The White Pass has an elevation of approximately 990 m (or 3,200 ft). At the BC-Yukon border, the route emerges from the Coast Mountains into the Intermountain Belt physiographic region of south-central Yukon Territory. From Skagway to the summit of the White Pass, the terrain is characterized by the extremely steep, deeply incised valley of the Skagway River. Ground conditions are controlled by glacially scoured bedrock exposed at surface. The bedrock consists of very hard and competent early Tertiary aged granitic plutonic rocks (quartz monzonites and granodiorties (Wheeler and McFeely, 1981).There is almost no unconsolidated sediment or soil development. This makes for costly foundation conditions as all tower foundations will required rock drilling. Access from the Klondike Highway to tower locations will also be difficult due to steep terrain and cliffs bordering the highway. On the Canadian side of the border, White Pass is characterized by its iconic desolate landscape. Similar to the US side of the pass, the landscape is exposed granitic bedrock at surface with little to no overburden. Unlike the US side, the Canadian side of White Pass reflects gentler topography throughout a broader mountain valley. Conditions in this area will also mean more costly foundations, as all towers will require drilling into hard, competent bedrock. Tower access will be less difficult due to the relatively gentler topography. Photo 2. South Klondike Highway traversing steep terrain with exposed bedrock in the Skagway River valley Photo 3. Canadian side of White Pass, looking north - 14 - Ground conditions are dominated by exposed granitic bedrock until the mouth of the Tutshi River, just before it discharges to the south end of Tutshi Lake (approximately km 47 of the alignment, see Map 3, Appendix A). North of the Tutshi River to Carcross, the terrain remains steep and mountainous, with the Klondike Highway immediately adjacent to Tutshi Lake and Windy Arm. In this area, however, unconsolidated sediments, typically sand, gravel, colluvium and till, are found at surface. Furthermore, bedrock conditions change to more friable meta-sedimentary rocks consisting of siltstones, shale and argillites. This bedrock can be more readily excavated with mechanical equipment. These conditions make foundations easier to construct with conventional augering or excavation similar to that used to construct power lines elsewhere in the Yukon. The majority of this area is well drained, granular material and there are no extensive areas of permafrost, wetland or other soft ground conditions. The most significant terrain hazard in this section of the alignment is the numerous avalanche paths along both Tutshi Lake and Windy Arm. See the following section for a discussion of avalanche hazards. From Carcross north to Whitehorse, the topography is characterized by a gentler, broad rolling valley. Terrain conditions are primarily well drained, unconsolidated sediments consisting of glaciofluvial and fluvial sand and gravel and glacial till. Bedrock is exposed at, or near, surface for less than 10% of the alignment between Carcross and Whitehorse. There are very few areas of soft ground or wetlands for alignments in proximity to the South Klondike Highway. There are more areas of wetlands near the railway alignment, particularly south of Rat Lake and Cowley Lake. These areas represent less than 5% of the total alignment and do not represent a significant constraint to the transmission line. Overall the terrain conditions for the Carcross to Whitehorse segment are amenable to conventional transmission line construction methods. 3.4.1 Avalanche Hazards Avalanches likely represent the most significant terrain hazard along the corridor. The avalanche risk has been well assessed and is actively managed during the winter months as part of maintenance of the South Klondike Highway. Avalanche paths have been mapped previously (Acres & Stethem,1987; Stethem and EBA Engineering, 1986) and are shown on the maps in Appendix A. The avalanche paths have been classified as high, medium or low risk based on the reported frequency of avalanches. This classification is based on the "Avalanche Hazard Index" reported in Photo 4. View of the avalanche path on Mt. Racine, just south of the BC/Yukon border. This represents one of the most significant avalanche locations along the corridor. - 15 - the Klondike Highway Avalanche Control Study. For the Canadian portion of the alignment, the classification was generally as follows: High risk paths are areas where avalanches occur annually; Moderate risk areas represent avalanche frequency of 1 in 2 or 1 in 5 years; Low risk areas represent avalanche frequency of 1 in 10 years or greater. Avalanche prone areas are found: on the Alaska side of White Pass (km 8 -19); near Summit Lake on the Canadian side of White Pass (km 21-23); between Fraser and Log Cabin (km 33-37); along the south end of Tutshi Lake (km 52-56); and at the south end of Windy Arm (km 72-78). In total, there are approximately 17 km of avalanche terrain traversed by the alignment; given the constraints presented by the topography, in most locations the avalanche terrain cannot be avoided. There are several approaches to structural avalanche defense. These include restricting avalanche release in the starting zone with supporting structures such as retarding fences and snow barriers, or terracing the land; altering the course of avalanche runout zones using deflecting berms or catchment dams; and installing direct protection structures such as splitting wedges or impact berms. Usually, some combination of these alternatives is able to reduce but not completely eliminate the risk exposure. High risk areas that cannot be avoided will require defense structures. Moderate risk areas would warrant defense structures or strong transmission line structures, but not as costly as those required in high risk areas. For the purposes of this study, the specific avalanche defense has not been defined, however additional cost allowance has been made for the segments of transmission line traversing the high and moderate risk avalanche terrain. A description of some of the methods for protecting transmission lines with avalanche defense structures is as follows: Supporting Structures Supporting structures consist of securely anchored latticed fences, wire rope nets, or vertical rakes that hold the snowpack in place within the starting zone to inhibit avalanche release. Because of their expense, maintenance, and work outside (uphill) the transmission line corridor, there are usually better choices for protecting transmission structures. Deflecting Berms, Retarding Mounds, and Catchment Dams Avalanche deflecting berms, constructed of earth fill, concrete, or steel, are designed to alter the direction of avalanche flow in the runout zone in order to protect facilities that might otherwise be hit. Retarding mounds are large piles of earth (7.5 – 10.5m high) built in a series of staggered rows across the width of the runout zone at right angles to the direction of avalanche flow. Catchment dams are large earthen berms with an upslope containment area designed to retard and catch - 16 - flowing snow and reduce avalanche runout distance. Though effective with small to moderate-sized flowing slides on lower gradient slopes, retarding mounds and catchment dams tend to be over- ridden by large, fast-moving powder avalanches. They are generally ineffective for paths that produce multiple slides in a given year, thus decreasing the effective retaining qualities of the catchment structures. Additionally, they require a large area for construction and major re- contouring of the local topography. Direct Protection Structures Direct protection structures for transmission line structures include reinforced splitting wedges, impact structures, and direct reinforcement of the transmission structure itself. Built using steel pile, reinforced concrete, or earthen-filled wood crib construction, these structures are designed to provide complete protection from avalanche impact and depositional loads. Their advantage is that they require only a small space to construct, usually within the transmission right of way, and can be designed using available materials. Their disadvantage is the cost, which can equal or exceed the cost of a transmission structure. Additionally, because of the massive forces to which they are subjected, the foundations and structures require special design considerations. If unstable soils or permafrost exist at the site, this complicates the issue and increases the cost. For new structures placed in known avalanche zones, the transmission structures and foundation can be designed for anticipated avalanche forces. The disadvantage of doing this is a failure of the avalanche defense structure results in a failure of the transmission line. For existing structures susceptible to avalanche damage, and for new structures placed in high impact zones, the preferred protection method usually is constructing a splitting wedge structure uphill of the transmission line structure. 3.5 ROUTE DESCRIPTION 3.5.1 Skagway to US/Canada border (Map 1) Only one route option was identified through this section of the transmission corridor, and is shown on Map 1. The route would run parallel to the Klondike Highway as it climbs up to White Pass, and crossing it at two locations (km 4 and 16.5) to take advantage of preferred terrain/avoid constraints. Commencing at the proposed substation at the Dyea Road junction with the highway, the Photo 5. Example of avalanche splitting wedge on Snettisham transmission line in Southeast Alaska. - 17 - transmission line would be located between the highway and the Skagway River as it traverses the flatter portion of the valley floor. Near km 4, the line would cross the highway and up onto the hillside above the highway. From here, the route would continue to traverse the hillside above the highway crossing several avalanche paths that flow down from higher elevations along the ridges at Porcupine Hill, as shown on the map. The route continues to climb up to the summit, crossing the highway at ~ km 16.5 to the east side. The lands crossed by the transmission line consist primarily of State lands, and some Municipal lands (Skagway) and Mental Health Trust Lands located closer to Skagway. As the first 4 km out of the substation can be reasonably accessed by new trails using tracked or wheeled vehicles, it is assumed that wood H-frame structures would be used. After this, the terrain steepens as the highway climbs to the summit. The highway has been cut into a rock mountain with little room for a transmission line. This 15 km section is assumed to be constructed by helicopters, using rock anchor foundations and steel structures. As noted above, several avalanche paths are crossed as the line climbs up to the US/Canada border, and in these areas, it may be advisable to provide defenses for structures in high risk areas (see example in Photo 5). As it is not feasible to avoid the avalanche paths entirely, the placement of structures near the runout zones will generally have lower risk than if structures are placed higher up the avalanche track. Final alignment and tower design will incorporate measures to appropriately manage risks of avalanches to the transmission line. As most of the route is elevated above the highway, and would only cross the highway in two locations, its visibility to vehicle traffic in either direction would be screened by vegetation to some degree. The route’s visibility from the White Pass and Yukon Railway through the lower part of the valley will very much depend on the extent to which vegetation and elevation differences between the railway route and transmission line provide a visual separation and screen it from view. 3.5.2 US/Canada Border to Carcross (Maps 2 - 5) This portion of the route traverses the mountainous terrain through the White Pass area, and descends into Carcross, a distance of approximately 80 km. From the border to Fraser customs, two route options were identified along either side of Summit Lake: one generally following the Highway, and the other generally following the White Pass railway. These two route options are shown on Map 2 (km 19- 30). Key routing considerations for locating a transmission line between the US/Canada border and Carcross are: access for construction/maintenance; terrain and avalanche risk; and viewscapes. Photo 6. Example of installing Y-poles by helicopter in Southeast Alaska (Photo courtesy of Dryden & LaRue) - 18 - While the highway option offers better accessibility, it is one of the most scenic portions of the South Klondike Highway, and the lack of trees /vegetation in the sub-alpine area limits the ability to screen the transmission line from the highway traffic. Much of the non-motorized recreation in the White Pass area is concentrated on the northwest side of the highway whereas snow machine usage occurs extensively on both sides of the valley. Careful alignment and tower placement would only mitigate visual effects of the transmission line to a limited extent. Option B (shown on Map 2) is an alternative route that may reduce visual effects as seen from the highway. The line would be located on the opposite side of Summit Lake, where it would be further away, and thus potentially less visible to vehicle traffic and recreational users on the northwest side of the highway. Conversely, it would be potentially more visible from the White Pass tourist train that operates between Skagway and Log Cabin during the summer. The terrain in this area consists of shallow linear gullies oriented parallel to the railway (northeast-southwest), and it may be possible to locate the transmission line along the bottom of these shallow gullies, thereby minimizing its prominence on the landscape. As there is presently no road access along Option B, access for construction and maintenance would be more difficult, and therefore more expensive than Option A which is located close to the Klondike highway. From Fraser to the south end of Tutshi Lake (km 30-50), a single route option is shown that follows the highway. The transmission route would adopt a straighter alignment than the highway, following the west and north sides of the highway, and above the Tutshi River (Map 3). Given the rugged, exposed bedrock conditions between US/Canada border and Tutshi Lake it is assumed that a single-foundation steel Y-tower would be used to reduce foundation costs. Continuing along Tutshi Lake and Windy Arm (Tagish Lake), only one route option is identified (see Maps 3 – 5). From km 50 to km 95, the transmission route would follow the west side (uphill) side of the Klondike Highway. Throughout this area, options for locating a transmission line are constrained by the highway and the lake(s), and must traverse the steep, avalanche prone slopes above the highway. Avalanches start high above the highway and at times, the runout zones extend across the highway and out onto the lake. The areas prone to avalanches affect approximately 13.5 km of the route, and are shown on Maps 2, 3 and 4. Given the steep topography through this area, there are no feasible options that entirely avoid the avalanche zones. Careful route alignment, design of structures and their placement will be key to managing risks to the transmission line from avalanche activity. Land tenure in this portion of the route consists primarily of Crown lands and Settlement Lands in the Yukon portion. The portion of the transmission line that is in British Columbia, a distance of approximately 55 km, is primarily on Crown lands; there are a few parcels of tenured land at Fraser, Log Cabin, and a viewing facility overlooking the Tutshi River rapids at km 42. The White Pass & Yukon Railway and Klondike Highway rights-of-way are established, tenured transportation corridors. Parks Canada manages the Chilkoot Trail National Historic Site, and the egress from the Chilkoot Trail at Log Cabin. The suggested alignment is outside of the boundaries of the Chilkoot Trail National Historic Site. - 19 - 3.5.3 Carcross (Map 5) Land tenure and land use are the primary challenges in locating a transmission line route through the community of Carcross. As shown on Map 5, there is little vacant land in the centre of the community, and both Settlement and private lands surround much of Carcross. Starting at km 95, just south of Carcross, three options have been identified for routing a transmission line through, or around, Carcross. These are shown as Options A, B, and C on Map 5, and are described below. Option A would cross Nares Lake near the narrows (~ km 96) and run along the northeast side of Nares Lake, crossing the Tagish Road about 2 km east of Carcross. This option would circumvent much of the built up part of Carcross itself, but would be in close proximity to the Chootla subdivision. The crossing of Nares Lake would be an overhead span, unless circumstances require a more expensive underwater crossing. Option B starts at approximately km 98, span the Nares River just east of the highway bridge, and weaves through the town, staying as much as possible on Crown lands (see Map 5 inset). This option would avoid, as much as possible, crossing tenured lands, by following existing utility and/or transportation easements. Option B would converge with the ATCO Electric easement in Carcross. Option C starts at km 95, and follow a former easement for the power line that used to connect to Venus Mine (now abandoned). This option would involve a submerged crossing of Bennett Lake, and join up with the railway right-of-way. Settlement lands and private lands are common to all three options in Carcross, and discussions with the Carcross Tagish First Nation, private land owners, and the Carcross community will be necessary to properly identify a preferred route through the community. 3.5.4 Carcross to Whitehorse (Maps 5-8) From Carcross to Whitehorse, a distance of approximately 70 km, three route options were identified. These three options from Carcross to Whitehorse are described as follows: Option A : A new route that generally parallels the South Klondike highway north of Carcross until Kookatsoon Lake, where it would converge with Option C, and follow the White Pass railway to Yukon Energy’s property at the Whitehorse Rapid Generating Station and then across the Yukon River to the Riverside Substation. This option is generally similar to that presented previously in the 1983 Whitehorse-Skagway transmission feasibility study (FMS Engineers) but takes into consideration the now greater extent of land ownership and development along the South Klondike Highway. Option B: The existing ATCO Electric easement would be upgraded to accommodate both the new higher voltage transmission line and the lower voltage distribution line on the same poles, using the existing easement. This option continues along the Klondike Highway to its junction with the Alaska Highway, and from there continues towards Whitehorse to km 168 where it drops down toward the Yukon River and Yukon Energy’s facility (and would then cross to the Riverside substation). - 20 - Option C: A new route that would generally follow the existing White Pass & Yukon Route (WP&YR) railway. Options A and C converge just south of Mary Lake subdivision, and from there, a single option would continue along the railway and across to Riverside Substation (as described for Option A). At this stage of route identification, the options shown are not intended to depict precise alignment, as it is understood that detailed route alignment would be done in the next phase of work, assuming the project is found to be feasible. New easements created for a transmission line would cross Settlement Lands in some locations, but the alignments shown largely avoid crossing private lands. During detailed route planning, careful selection of the alignment would minimize these overlaps. To the extent that existing rights-of-way or easements (i.e. highway, WP&YR and ATCO Electric Yukon) can be partially/wholly utilized, the footprint/clearing required for a new transmission line could be reduced, and existing linear infrastructure could also be utilized for access during construction and maintenance. In this regard, access for line construction and maintenance would be somewhat more challenging along the WP&YR as compared to the other options that generally parallel the highway. North of Kookatsoon Lake (km 146-150), options A and C would converge, and continue toward Whitehorse parallel to the WP&YR railway, thereby avoiding the residential development at the junction of the South Klondike and Alaska highways, the CTFN residential subdivision east of the Cowley Creek subdivision, and the multitude of residential, commercial and other land uses along the Alaska Highway to Robert Service Way in the City of Whitehorse. A new country residential subdivision is being planned for the area west of Kookatsoon Lake (McGowan Lands subdivision proposal). Depending on the configuration of this planned development, it may be desirable to re- route Option A to avoid this planned subdivision area. As noted above, Option B would utilize the existing ATCO Electric easement, replacing existing poles with taller structures. The clearing width for the taller structures would likely extend beyond the existing easement in order to conform to current electrical standards. It is expected that the existing 12 m easement would need to be widened to 16 m to accommodate the new, taller structures. - 21 - Table 1 provides a summary of the route options for the entire length of the transmission line, and the approximate distances for each segment. Table 1: Summary of Transmission Conceptual Alignment Options Approximate KMP Route Description Option A Option B Option C 0-19 Skagway to US/Canada Border Klondike Highway n/a n/a 19-30 Border to Fraser Klondike Highway Option B east of WP&YR1 n/a 30 - 95 Fraser to near Carcross Klondike Highway n/a n/a 95 -105 Carcross area Crosses Nares Lake2 Klondike Highway Submerged crossing of Bennett Lake 105-170 Carcross to Whitehorse New ROW along Klondike Highway3 Existing ATCO Electric Yukon ROW4 New ROW along WP&YR Notes: 1 Options for traversing scenic White Pass area are identified on maps, but costing assumptions are same for each route option in this area. 2 This could also be a submerged crossing, but long overhead span is feasible and less expensive 3 Option A and C converge south of Mary Lake and continue as single route into Riverside substation 4 Existing ATCO Electric Yukon easement may require widening to accommodate higher voltage transmission 3.6 TRANSMISSION LINE DESIGN Preliminary research was done in order to anticipate the design criteria for the project. This information was used to assist in selecting preliminary line characteristics for this feasibility study, such as conductor size and structure configuration. Due to varied climatic conditions and right-of- way restrictions along the proposed transmission line, several different structural configurations were considered, including single wood pole “wishbone” structures, double wood pole H-frame structures, and steel pole “Y” towers. In addition, the Government of Yukon wished to examine the possibility of an under-build 4 of a communication fibre to address a future communication intertie between Whitehorse and Skagway. Conductor sag and tension loads, and structure loads were estimated based on the anticipated climatic load data (see Appendix D for Design Criteria). These loads were then used to determine preliminary structure framing configurations, heights, weights and spans. This information forms the basis of the project construction cost estimate in this feasibility study. Cost estimates are not included in this technical memorandum, but will be included in the final report. 4 Under-build refers to using the same structures (poles) to support both the electrical transmission and the fibre optic cable, thus avoiding cost of burying the fibre cable in a separate easement. - 22 - As noted elsewhere in this report, further investigation of local site and climatic conditions will be required in order to complete the detailed engineering design for the project. All criteria and line configurations assumed in this study shall be subject to review if the project proceeds to the implementation stage. 3.6.1 Wires 3.6.1.1 Electrical Conductors 336.4 kcmil 30/7 “Oriole” ACSR conductor was assumed for this feasibility study due to its ability to meet the requirements of voltage drop for the project. However, the final choice of conductor size would be made at the detailed design stage, depending on the financial acceptability regarding losses along the line. 3.6.1.2 Fibre-Optic Under-build For the fibre option under-build scenario, a CC-57/465 OPGW w/ 24-36-48 Corning SMF-28E single mode fibre was assumed in this study. It is expected that this wire will meet the requirements outlined in the report, “Feasibility Study for Alternative Yukon Fibre Optic Link – Summary Report” (Planetworks, February 2014); however, it would need to be reviewed during detailed design to ensure that it meets the final design requirements of the communication line. 3.6.1.3 Overhead Shield Wire (OHSW) Based on information provided in the Northern Canada Power Commission “Whitehorse – Skagway Transmission line Feasibility Study” (FMS Engineers, 1983), it was determined that due to the area’s very low isoceraunic level5, only the first 1.6 km south of Whitehorse requires an overhead shield wire. On the Alaskan side, it was assumed that OHSW would be required for 1.6km out of the Skagway substation, as was also assumed in the above referenced 1983 study. 3.6.2 Insulators Standard 138 kV porcelain insulator sets were assumed for this study. Insulator design would be revisited during the detailed design stage, following electrical review. Particular areas of concern include high-altitude and high-moisture regions. 3.6.3 Wood Pole Structures Several types of wood pole structures were considered for the proposed transmission line. In areas with sufficient right-of-way width, two-pole H-frame structures were considered, while single-pole “wishbone” structures were considered for areas with limited space such as the ATCO Electric Yukon 5 Isoceraunic: Indicating or having equal frequency or intensity of thunderstorm activity. An isoceraunic line is a line drawn through geographical points at which some phenomenon connected with thunderstorms has the same frequency or intensity; used for lines of equal frequency of lightning discharges. - 23 - easement. These structures are illustrated in the following subsections below. For each structure type, two configurations are considered: with or without a communication fibre under-build. Structures with a fibre under-build must conform to a higher standard than those without the fibre under-build, resulting in stronger structures or shorter spans to accommodate the greater structural load requirements. In general, Western Red Cedar poles have been assumed because of their greater availability on the west coast. The following sections describe the most likely structures that would be used for the route within Canada. Structures used in the Alaska portion of the route are assumed to be wood pole H-frame in the first 4 km along the valley floor, and thereafter steel structures for the next 15 km up to the US/Canada border, as discussed in section 3.5.1. These steel structures would be continued through White Pass to Tutshi Lake due to terrain condtions and associated foundation costs. See section 3.6.4 for a discussion of the steel structure. Wood pole structures that would be appropriate for the portion of the route between Tutshi Lake and Carcross, and between Carcross and Whitehorse, are discussed as follows. Table 8 provides a summary of the types of structures that would most likely be used in different portions of the route. South End Tutshi Lake to Carcross For the portion of the route between the south end of Tutshi Lake and Carcross (km 51-100), wood H-frame structures are well suited to portions of the alignment with low avalanche risk, granular or cohesive soils and sufficient right-of-way to accommodate their wider footprint. H-frame structures will also accommodate the relatively high climatic loads of the area. H-frame structures would be used for most of this portion of the route, although steel towers, as described in section 3.6.4, are likely to be used across avalanche slopes. The H-frame structures are anticipated to consist of two Western Red Cedar poles joined by a top horizontal cross arm and steel cross-bracing. For H-frames with and without a fibre under-build, it is expected that 21.3m (70 ft.) poles will provide an economical design. Figure 3 illustrates the H-frame structures, with and without a fibre under-build. The estimated allowable spans for H-Frames with and without a fibre under-build are summarized in Table 2. The effect on right-of-way width of inclined grade and sidehill slope would be accounted for in the detailed design, but it is expected to have a negligible effect on the material costs for the project. Table 2: Anticipated Allowable Spans for Double-Pole H-Frame Structures – White Pass to Carcross No Fibre Under-Build Including Fibre Under-Build Basic Span (m) 180 150 Max Wind Span (m) 280 280 Max Weight Span (m) 1,230 1,230 Max Span - Wire Ground Clearance-Governed (m) 200 170 - 24 - Figure 3: Double Pole H-Frame Structures White Pass to Carcross: a) with and b) without Fibre Under-build Carcross to Whitehorse Between Carcross and Whitehorse (km 100-170), double-pole H-frame structures were considered for Options A and C (see Maps 5-8) because they are well suited to the rolling, open terrain and soil conditions. As H-frame structures require wider right-of-way width than single-pole wishbone structures, the H-frame structures are most suitable for Options A and C where a new right-of-way is considered. Economy can be obtained through the use of longer spans and fewer structures, provided that sufficient right-of-way is available and they are founded in granular or cohesive soil rather than rock. The H-frame structures would be similar to those described above for the route south of Carcross, but a shorter height (see Figure 4). The poles would be 18.3m (60ft.) tall without a fibre under- build, and 19.8m (65ft.) tall with a fibre under-build. The estimated allowable spans for H-Frames with and without a fibre under-build are summarized in Table 3 below for horizontal line angles up to a maximum of 4o and flat ground. Table 3: Anticipated Allowable Spans for Double-Pole H-Frame Structures – Carcross to Whitehorse No Fibre Under-Build Including Fibre Under-Build Basic Span (m) 225 180 Max Wind Span (m) 354 345 Max Weight Span (m) 2,000 2,000 Max Span - Wire Ground Clearance-Governed (m) 250 200 - 25 - Figure 4: Double-Pole H-Frame Structures Carcross to Whitehorse: (a) with, and (b) without Fibre Under-build Option B (see Maps 5-8 in Appendix A) would utilize the existing ATCO Electric Yukon easement. For this option, single-pole wishbone structures were considered because their shorter spans, lower height and narrower horizontal spacing between conductors are well-suited a narrower right-of-way (16 m) with frequent changes in horizontal alignment. Under this option, the structures would accommodate a possible fibre under-build, as well as the 34.5kV distribution line under-build. The wishbone structures are anticipated to consist of a single Western Red Cedar pole supporting two steel cross arms at the top of the pole and a wooden cross arm at the distribution under-build elevation (see Figure 5). It is expected that 16.8m (55 ft.) poles will provide an economical design for poles with or without a fibre under-build. The estimated allowable spans for wishbone structures with and without a fibre under-build are summarized in Table 4 below for horizontal line angles up to a maximum of 3o and flat ground. Table 4: Anticipated Allowable Spans for Single-Pole Wishbone Structures – Option B Carcross to Whitehorse No Fibre Under-Build Including Fibre Under-Build Basic Span (m) 65 55 Max Wind Span (m) 72 62 Max Weight Span (m) 413 414 Max Span - Wire Ground Clearance-Governed (m) 80 75 - 26 - Figure 5. Wishbone Structures: (a) with, and (b) without Fibre Under-build 3.6.4 Steel Structures Self-supporting steel Y-Pole structures (see Figure 6) were considered as an alternative to wood structures for portions of the proposed alignment south of Carcross, from the Alaskan border to the south end of Tutshi Lake, and along all areas of medium to high avalanche risk. Steel structures are well suited to this segment of the alignment given their higher strength for the high climatic loads and avalanche risk, suitability for helicopter installation in remote locations, and ability to be founded directly on rock using rock anchors, or into soil through a single concrete caisson per pole. Three different steel Y-Pole structures were considered, based on their application: basic towers with and without a fibre under-build and a taller higher-strength tower for regions of moderate avalanche risk. Towers with a fibre under-build must be constructed to a higher standard, which results in stronger structures or shorter spans to accommodate the greater structural load requirements. The total estimated weights and allowable spans for the different steel Y-Pole tower applications are summarized in Table 5 and Table 6 below for horizontal line angles up to a maximum of 4o and flat ground. The effect of inclined grade and sidehill slope would be accounted for as part of the detailed design, although it is expected to have a negligible effect on the material costs for the project. - 27 - Table 5: Estimated Weights of Steel Y-Pole Towers Application Tower Weight (kg) Tangent Tower, No Fibre 3,060 Tangent Tower, Fibre Under-Build 2,730 Tangent Tower, Low to Moderate Avalanche Risk Areas 4,800 Table 6: Anticipated Spans for Steel Y-Pole Structures (Low to Moderate Avalanche Risk) No Fibre Under-Build Including Fibre Under-Build Basic Span (m) 300 230 Max Wind Span (m) 330 260 Max Weight Span (m) 1,230 1,230 Max Span - Wire Ground Clearance-Governed (m) 325 250 Figure 6: Steel Y-Pole Structures between White Pass and Carcross - 28 - As discussed previously, there conceptual transmission line alignment traverses several known avalanche paths south of Carcross. The following sections are considered moderate to high avalanche risk (stations relative to to the start of the Klondike Highway in Skagway, AK, see Appendix A for locations): Kilometre 57.8 to 60.0 (2.2 km - south end of Tutshi Lake) Kilometre 78.3 to 80.1 (1.8 km - Mount Racine) Kilometre 81.1 to 84.8 (3.7 km - Dail Peak) Where it is not possible to avoid the avalanche-prone areas entirely, it is expected that moderate- risk avalanche areas will be accommodated by the installation of taller, higher-strength steel pole structures (anticipated heights 4.0 m taller and design loads double those which are required by code) and that structures in high-risk avalanche areas may be protected by separate defensive structures. For the structure configurations assumed in this study, it is assumed that the entire length of the avalanche-prone regions identified above will have high-strength steel structures, while only a total of 1 km in the south Tutshi Lake region, 0.4 km in the Mount Racine region and 0.5km in the Dall Peak region may have separate defensive structures. For the detailed design of the transmission line, it is recommended that an avalanche specialist be retained to review the avalanche hazard areas and provide avalanche design criteria for the project. 3.6.5 Right-of-Way Requirements The minimum right-of-way dimensions for the proposed 138 kV transmission line were estimated based on anticipated loading conditions and minimum horizontal clearance requirements associated with the assumed conductor sizes and spans for different structure configurations. Table 7 summarizes the minimum right of way widths estimated for different portions of the alignment. Note that the increased right of way width requirement for steel Y-Poles without a fibre under-build stems from these poles having significantly longer spans and greater conductor side-sway under maximum wind conditions than Y-Poles with a fibre under-build. Table 7: Minimum Right of Way Widths for Structures Structure Type Estimated Minimum Right of Way Width (m) Wood Double-Pole H-Frame (with and without fibre under-build) 23 Wood Single-Pole “Wishbone” (with and without fibre under-build) 16 Steel Y-Pole (without fibre under-build) 34 Steel Y-Pole (with fibre under-build) 28 - 29 - 3.6.6 Summary of Transmission Line Structures Table 8 provides a summary of the anticipated type of structure for various segments of the transmission route between Skagway and Whitehorse. Options A, B, and C correspond to the three route options identified for that portion between Carcross and Whitehorse (see Maps 5-8). Steel structures would be used in challenging terrain south of, and throughout the White Pass area, and in specific areas exposed to moderate to high avalanche risk. Table 8: Summary of Structure Type, by Route Segment Segment KMP (approx.) Option A New Right-of-Way Option B ATCO Electric Easement Option C New Right-of- Way Alaska – lower Skagway valley 0-4 Wood H-frame n/a n/a Alaska – to White Pass 4-20 Steel Y-poles n/a n/a White Pass to Tutshi Lake 20- 51 Steel Y-poles n/a n/a Tutshi Lake to Carcross 51- 100 Wood H-frame1 n/a n/a Carcross to Whitehorse Km 100 to 170 Wood H-frame Wood – Single Pole Wishbone Wood H-Frame Notes: 1 Steel structures assumed for avalanche terrain along Tutshi Lake and Windy Arm – total distance approximately 7.7 km - 30 - 4. REVIEW OF WEST CREEK HYDRO POTENTIAL 4.1 BACKGROUND AND CONTEXT The West Creek hydro site is a key factor in assessing the viability of a potential Skagway- Whitehorse transmission line. West Creek hydro could provide cruise ships in Skagway with power during the summer months and winter power to the Yukon via the transmission line. A review of the West Creek hydro site has been conducted to identify the hydro potential and value of the site as well as identify the main data gaps in earlier studies. The review was based on available reference studies, a site visit and professional opinion. The Municipality of Skagway reports that they are currently working through a Memorandum of Understanding with Alaska Power and Telephone (AP&T) to advance the Federal Energy Regulatory Commission (FERC) license submission for the West Creek initiative. The Municipality is currently conducting hydrologic analysis of the catchment in support of feasibility and licensing requirements and is also preparing a scope and budget to address the additional FERC licensing requirements. Accordingly, the following review does not necessarily represent to views or opinion of the Municipality of Skagway, Alaska Power & Telephone Company or their technical consultants. The review included an estimate of the available power and energy potential at the site, a technical review of each of the major components (dam, powerhouse, conveyance, access and transmission) and provides recommendations for future alternatives that can be considered. The complete hydro potential review is included in Appendix E. A summary of is presented herein. The West Creek hydro site, as well as the Upper Lynn Canal region of Southeast Alaska, have been the subject of numerous previous hydro potential studies since the 1960’s. There is a substantive supporting data set , much of it completed in 1981 to support the West Creek Hydro feasibility study. It includes: detail topographical mapping and aerial photography; a preliminary environmental study including supporting fieldwork; an extensive geotechnical investigation program, that included geological mapping, diamond core drilling, water pressure testing, seismic refraction surveys and material testing. A site reconnaissance was also conducted on August 19, 2014 by a hydrotechnical and a geological engineer. It included a helicopter flyover of the West Creek valley and a ground reconnaissance of the potential dam site and surroundings, with the observations focused on: Potential dam and powerhouse sites; Conveyance alternatives (penstock or tunnel) and alignments; Reservoir boundaries; Key geological features. - 31 - 4.2 HYDROLOGY AND POWER STUDIES 4.2.1 Hydrological Study The power and energy generation potential of the West Creek site was estimated on a monthly basis. Hydrological data for West Creek was retrieved from 15 years of daily flows recorded from 1962 to 1977 by the United States Geological Survey (USGS). The flow gauge was located approximately 200 m upstream of the mouth of the creek. The catchment area at this station is approximately 112 km² (42.4 square miles). Flow data measured at the West Creek gauging station was used to calculate flows in the catchment area upstream of the proposed dam site (96.3 km² or 37.4 square miles), resulting in a calculated average yearly flow of 8.2 m³/s, for an average flow yield of 0.085 m³/s per square kilometer. Average historical monthly flows for West Creek at the dam site are presented in Table 9 and Figure 7. Table 9: Average Monthly Flows on West Creek at Dam Site Month Monthly average flow (m³/s) January 0.6 February 0.7 March 0.7 April 1.3 May 5.2 June 15.3 July 24.0 August 23.2 September 16.1 October 6.2 November 2.9 December 1.1 Yearly average 8.2 - 32 - Figure 7: Average Monthly Flows on West Creek at Dam Site 4.2.2 Power and Energy Estimates The power and energy generation potential of the West Creek site was estimated. An installed capacity of 25 MW was selected, consistent with the recent FERC Application submitted by AP&T (2014). Calculations were performed by simulating the reservoir operations on a monthly basis. The reservoir volume was determined based on the 1982 feasibility study (R.W. Beck). The storage volume available for power generation was estimated using the operating water levels for a 22.5 MW plant (determined in the updated 1983 feasibility study). Further optimization of the minimum and maximum operating water levels should be conducted; however, these 1983 values provide a reasonable estimate of power and energy generation for the purposes of this review. The following operating water levels and operation parameters were used for the simulations: Maximum operating water level = 238.4 m (782 ft) Minimum operating water level = 201.8 m (662 ft) Water level range of operation = 36.6 m (120 ft) Tailwater level = 11.2 m (38 ft) Storage volume in reservoir = 100 Mm³ Average net head = 200 m (estimated, including head losses) Turbine flow = 15 m³/s Turbine efficiency = 85% (constant) Minimum environmental flow of 10% of average monthly flow 0 5 10 15 20 25 30 Jan Feb March Apr May June July Aug Sep Oct Nov DecAverage monthly flow (m³/s) - 33 - A turbine flow of 15 m³/s was selected to match the proposed 25 MW installed capacity. It does, however, significantly exceed the average yearly flow of 8.2 m³/s at the dam site. It appears that the optimal installed capacity at the site would be in the 15 to 18 MW range based on available flow data. Reservoir operations were simulated to maximize winter energy generation. Such an objective appears to be the most optimal approach, assuming a transmission interconnection between Skagway and the Yukon. Summer energy could be provided to Skagway while the highly-valued winter energy would be available to the Yukon during the winter months. It is assumed that the reservoir would refill during the summer months (mainly June to August) and constant releases (when possible) were assumed during the winter months (from mid-November to mid-April) to increase the flows available for power generation. Calculations were made using a volume balance approach. This calculates the change in available storage and the associated monthly volume of water available for power generation. The following reservoir operational scheme was generally assumed in the calculations. Summer filling (target volume to be retained in each month, if possible) June: 15 Mm³ July: 40 Mm³ August: 35 Mm³ September: 10 Mm³ Winter releases from the reservoir November: 10 Mm³ December to March: 20 Mm³ per month April: 10 Mm³ Filling of the reservoir according to these simple rules occurred in all years except one of the flow series (14 years total). The calculated average monthly power production is presented in Table 10, while the average energy generated from the West Creek hydro site is presented in Figure 8Figure 7. Assuming the above operational scheme, total average yearly energy generation was estimated at 106 GWh, varying between 87 and 132 GWh over the duration of the 14 year flow series (see Figure 9 ). It should be noted that with the proposed scheme, the maximum average monthly power generated is 18 MW in September. The full 25 MW was only achieved (on a monthly average) 5 times in September over the duration of the flow series. Further optimization of the operational scheme or a change in priorities (i.e. favor summer energy over winter energy) could potentially result in a slight increase in total generation. A firm winter power between 11 and 13 MW can be achieved, if winter releases are optimized to achieve the largest possible firm power. - 34 - Table 10: Average Monthly Power Production; Calculated based on 1963-1977 Flows Month Average Power Production (MW) January 13.2 February 12.9 March 12.8 April 8.5 May 7.4 June 9.6 July 10.7 August 14.5 September 18.1 October 9.3 November 13.5 December 13.9 Yearly average 12.0 Figure 8: Average Monthly Energy with 25 MW Installed Capacity 4 5 6 7 8 9 10 11 12 13 14 Monthly energy (GWh) - 35 - Figure 9: Energy Generation by Year; based on 1963-1977 Flow Future Considerations The available hydrological information on West Creek is adequate for preliminary power and energy estimates, but should be updated for future estimates. The available data set is limited (14 years) and dates back more than 30 years. All of Southeast Alaska is experiencing significant climate change and a rapid melting of glaciers, which covers a noticeable part of the West Creek watershed. Hydrological monitoring is currently underway on West Creek and should continue until the project is developed. A single gauge near the mouth of the creek, or alternatively near the dam site, is adequate to measure flows. Meteorological and climate change studies would also help to understand and predict the hydrology of West Creek. Based on the above calculations and the selected turbine flow (15 m³/s) to match the proposed 25 MW capacity, it appears that the most economical installed capacity would be smaller, likely in the 15 to 18 MW range. Since one of the objectives of the West Creek hydro site is to provide shore power to the cruise ships visiting Skagway, 25 MW was originally proposed in order to fully meet that demand. Further studies based on power demand in both Skagway and Whitehorse are needed to determine the optimal installed capacity to develop at West Creek. At this stage, it does not appear warranted to build 25 MW of installed capacity. Reservoir operations should also be studied on a daily basis, incorporating the geometry of the proposed spill structures (overflow or gated). The reservoir size (and dam height) could be slightly increased, to generate more winter firm power at the site. There is sufficient inflow during the summer to achieve approximately 12 MW of firm winter power. The need for environmental flows below the dam, the resulting impact on the power and energy output of the site, would also need to be investigated. 60 70 80 90 100 110 120 130 140 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977Energy (GWh per year) - 36 - 4.3 REVIEW OF SITE DEVELOPMENT LAYOUTS Various potential layouts for the West Creek hydro site have been analyzed to develop between 5 and 25 MW of installed capacity, with a storage reservoir. The main project layout for the West Creek hydro site was included in the 1982-1983 feasibility study (R.W. Beck) which proposed a powerhouse near the mouth of West Creek on the Taiya River. In 2014, an alternate layout was proposed by AP&T with a powerhouse near tidewater on the Taiya Inlet. No technical information regarding the recent layout was made available for this review. The following sections present a review of the proposed infrastructure, key challenges and potential alternatives that should be considered in further studies. A photo log of the site visit is presented in Appendix E, along with drawings of the proposed layouts. 4.3.1 Dam and Spillway The proposed dam site is located approximately 3.5 km upstream from the mouth of West Creek. At this location the creek has a steep gradient and is flowing through a narrow valley between hills. This location is suitable for the construction of a dam, limiting the volume of material required for the structure and containing the reservoir behind the hills. Only one small closing dike (or saddle dam) on the left (north) abutment would be required for the largest development option (22.5 MW as proposed in the 1982 feasibility study). It was reported that bedrock at the dam site consists of a strong, massive granodiorite. This rock is suitable for supporting a dam at the site and also providing construction materials for the shells of an earth dam. Bedrock was observed near the surface at many locations during the site visit. It appears to be of fairly good quality, although foundation treatment is to be expected under the dam. An earthfill dam with a concrete face was first proposed in 1982. The absence of quality impervious material (i.e. till or clay) in the area was the main reason for proposing such a dam, instead of an earthfill dam with an impervious core. Studies in 1983 proposed a roller- compacted concrete (RCC) dam as the most economical dam type for the project. For both types of dams, it was proposed that a cutoff slab of about 60 cm in thickness and 3.5 m width and a grout curtain would allow to provide foundation water barrier and cutoff. The RCC type of dam was also the option presented in the 2014 FERC Application (AP&T). The reservoir lies in a fairly flat and narrow valley that is bordered by steep slopes coming down Photo 8. Potential dam site on West Creek, looking northeast towards the Tayia River valley. Photo 7. West Creek valley and potential reservoir area upstream of dam site. - 37 - from high mountain peaks. A significant landslide has occurred upstream of the reservoir near the West Creek glacier in the last decade, however the location of this landside upstream and above the potential reservoir limits. There are numerous visible avalanche paths on both sides of the reservoir. The risk of landslide or avalanche in the reservoir is a risk to the project to be considered in the design. An ungated overflow spillway excavated into bedrock on the dam right abutment was first proposed in 1982. It is designed to accommodate the probable maximum flood (PMF). In 1983, a modified spillway incorporated in the middle of the main dam was selected. This latter option is only suitable if a RCC dam is selected. No gated spillway structure was proposed in either design. Diversion during construction was proposed with two concrete pipes to convey the 1:10 year flood. Tunnel alternatives on the right and left abutment were also considered. The proposed dam site would require the construction of small cofferdams both upstream and downstream of the alignment to build the dam in the dry. Future Considerations The proposed dam location is the optimal one, within +/-200 meters. The final position should be confirmed based on additional geotechnical investigation and the type of dam selected (including dam height). From the available information and previous geological reports, it appears that the site geology is adequate to support a dam of the size proposed. A RCC dam is a suitable dam for the site but would be more expensive to build compared to an earthfill dam with impervious core. It may be worthwhile to investigate additional borrow sources for impervious material in the area or consider alternate core material. Consideration should also be given to an asphalt core dam. This is an emerging technology first implemented in Scandinavian countries. Hydro-Quebec has recently built a series of asphalt core dams - the first such works in North America. The West Creek dam is large enough to merit consideration of this option which may potentially reduce project costs. It is likely that a gated structure with a low invert would be required to discharge environmental flows below the dam site. It could also be used to flush sediment accumulation in the reservoir. Significant sediment build-up is not expected to occur on a regular basis, but the potential risk of landslides or avalanches deposited in the reservoir could affect sediment accumulation. Furthermore, landslides or avalanches released into the reservoir could generate a large wave that could threaten (overtop) the dam crest. Such events are considerations that must be taken into Photo 9. Potential reservoir in the West Creek valley, with large avalanche paths on the north side. - 38 - account in selecting the dam type. Depending on the severity of the effects on the reservoir (resulting flood-wave), a certain dam type may be preferable. 4.3.2 Conveyance and Powerhouse Various powerhouse locations were considered in the 1982-1983 feasibility study, all located near the mouth of West Creek. These locations would allow development of the full head available and to provide the shortest conveyance possible. The selection of the optimal location for the powerhouse was based on the results of the geotechnical investigations and the preferred route for the water conveyance. A 2.7 km long power tunnel was proposed for water conveyance. A 440 m steel penstock would complete the power conduit to the powerhouse. A surface powerhouse was proposed, equipped with two Francis turbines. The 2014 FERC Application (AP&T) proposed an alternate layout that included a powerhouse at the head of Taiya inlet near tidewater. A 4.9 km tunnel running down the Taiya River valley would convey the water from the intake structure at the dam to the powerhouse. This layout would avoid having the transmission line crossing through the Klondike Gold Rush National Historic Park. Note that AP&T already has a buried power line through the Park, extending almost to West Creek bridge. The powerhouse location proposed in 1982- 83 appears to be the optimal location, based strictly on a technical review of the available information and observations gathered during the site visit. It provides a shorter conveyance with fewer technical challenges, and the access to the powerhouse is much easier. A powerhouse on the Taiya Inlet would have many disadvantages: likely require a barge to access the site for construction; significant visual footprint on the road to Dyea and on the Dyea flats. large tailwater level variation that would be challenging to accommodate; longer conveyance that may have to cross fault zones (to be determined based on further site investigations). Photo 10. Mouth of West Creek with potential powerhouse locations. Photo 11. Approximate location of proposed powerhouse on Taiya Inlet in FERC 2014 Application - 39 - A surface powerhouse is adequate based on the site characteristics for both sites, however the Taiya Inlet site would require a large bedrock cut into the steep mountain side at tidewater to accommodate the powerhouse. The use of Francis turbines also appears to be adequate for the proposed head and turbine flow, although Pelton turbines could still be considered. Finally, a surge chamber/tank will likely be necessary, based on the head to be developed at the site. Future considerations The land use challenges associated with constructing a powerhouse near the mouth of West Creek should first be determined and include discussions with land owners in the area and the National Historic Park. The location at the mouth of West Creek is the prefered location from a technical and cost perspective. A powerhouse on Taiya Inlet presents significant technical challenges and would likely be more costly to develop. This option cannot be eliminated at this stage, but an adequate geotechnical investigation program would be necessary to determine its feasibility. As an alternative to a tunnel, a surface penstock for the full length of the water conveyance should be re-assessed. A power tunnel of the size required for the proposed turbine flow would likely be costly. An HDPE (plastic) penstock potentially could provide a lower cost alternative to a tunnel. The penstock could be buried to protect it against potential landslides or avalanches as well as against freezing. Based on topographical information, a penstock would be located on the north side of the creek, extending for about 3.4 km. The feasibility of locating the powerhouse on the north side of the creek would be assessed in parallel. Finally, the potential intake location is another factor that can influence the selection of a specific alignment or conveyance type for the site. Due to the large water level variations (37 m) in the reservoir, an intake excavated into bedrock is mandatory for stability purposes. Optimization studies should consider all components described above as a package (intake structure, water conveyance and powerhouse), to determine the most optimal layout. Multiple alternatives should be re-assessed, since technologies have evolved and unit construction costs have increased significantly since the early 1980’s. 4.3.3 Site Access Road access to the West Creek hydro site already exists. Road access to Skagway is possible via the South Klondike Highway, and marine access is available via the Lynn Canal. There is an all-season road that runs from Skagway to Dyea that is suitable to bring machinery on site, although it is quite narrow with sharp curves. There is an old logging road that runs parallel to the creek on the north side and extends close to the proposed dam site (approximately 300-400 m). This road could be upgraded for construction access and extended to the proposed reservoir for clearing. Access to the south side of the creek could be required near the dam or near the mouth of the creek, depending on the selected location for dam components. A bridge over the creek could be built at the dam site if required, while existing road/trails near Dyea do give access to the south side of the creek. If the powerhouse was located on Taiya Inlet, access would be more challenging as mentioned before. A barge would likely be used to access the powerhouse location, unless suitable road access - 40 - could be established on the west side of the river. Such an access road would need to extend to the edge of the water on Taiya Inlet. If the use of a barge is selected, landing spots on each side of the inlet would need to be built and be able to accommodate large tides. There are two options for a transmission line between the West Creek hydro site and Skagway: An overhead line parallel to the existing road and/or an underground line. The costs associated with each would need to be assessed, along with land use and effects on viewsheds. Future considerations The cost associated with developing a new access road or the use a barge should be factored into the selection of the powerhouse location (near the mouth of West Creek or at Taiya inlet). In general, access to the site is by virtue of the existing road network, and only a few kilometers of new access road is required. Roads to the dam site and powerhouse site would be maintained for year- round access. Preliminary recommendations for further technical evaluation of the West Creek hydro site and cost estimates are provided in Appendix E. 4.4 REVIEW OF ENVIRONMENTAL AND REGULATORY ISSUES ASSOCIATED WITH WEST CREEK HYDRO DEVELOPMENT A cursory review of the environmental and regulatory issues associated with the proposed West Creek Hydro project was undertaken by Travis/Peterson Environmental Consulting Inc. based in Anchorage Alaska. The purpose of this review was to identify any key environmental constraints and regulatory issues that are associated with the West Creek hydro development. The following documents were reviewed: 1. R.W. Beck Feasibility Study 1981-82 2. Alaska Power and Telephone Company Federal Energy Regulatory Commission (FERC) Application, March 2014 3. The Alaska Department of Transportation and Public Facilities (COT&PF) Juneau Access Improvements Project EIS, April 2005; and 4. The Lynn Canal Conservation website. - 41 - Based on the information reviewed, the West Creek drainage is compatible with hydro power, as the valley has no endangered species, critical habitats, deer habitat, or salmon spawning. Five other issues were identified, however, that are likely to require considerable effort and resources to address. These are: 1. Complying with Executive Order 12114 (“Environmental Effects Abroad of Major Federal Actions”, 2. Construction within the Klondike Gold Rush National Historical Park 3. Protecting Viewsheds 4. Compliance with Section 106 of the National Historic Preservation Act (NHPA); and 5. Acquiring Presidential approval to export electricity to Canada. It was assumed that the West Creek hydro development and a transmission line between Alaska and Yukon are linked; one would not be built without the other (within a reasonable period of time). The following expands on each of these five issues. Executive Order 12114: FERC will require and Environmental Impact Statement (EIS) for the West Creek hydro project. Executive Order 12114 mandates every Federal agency implementing the EIS process (i.e. FERC) to quantify the environmental effects outside the United States borders. Agencies must consult with the Department of State and the White House Office on Environmental Quality concerning any proposed mitigation procedures prior to implementing them. This coordination will complicate FERC approval of the EIS. Construction within the Klondike Gold Rush National Park: The National Parks Service (NPS) manages the Klondike Gold Rush National Historic Park in Alaska. Since the powerhouse may be located on Park land or within the Park boundary, the NPS will be involved in the EIS process. The use of Park land for project-related infrastructure is only allowed if there are no feasible alternatives. Experience suggests that NPS is very protective of its lands and it is likely that an exhaustive study of alternatives will be needed to demonstrate that the use Park land for any project structure is justified. Viewshed Protection: The National Parks Service is extremely concerned about protecting viewsheds. They often require detailed modeling of viewsheds to assess the impact of developments on the viewshed within the Park. This involves complex computer simulations of the project infrastructure against photographs of the surrounding environment. The analysis of views is subjective, and as such, often controversial. Compliance with Section 106 of the National Historic Preservation Act (NHPA): Section 106 of the NHPA will require extensive coordination with the State Historical Preservation Office (SHPO) and Keeper of the Historic Register given the historic districts near the West Creek site. The Keeper has the authority to ban any portion of the project from the Park, or in close proximity to structures that are on the National Historic Register, or have the potential to be on the Register. Impacting a viewshed of a structure on the Register requires mitigation. The SHPO and Keeper will require a detailed archaeological and cultural resource study of the project area that could take several years to complete. - 42 - Presidential Approval to Export Electricity to Canada: The Federal Power Act of 1935 requires a Presidential Approval to construct a transmission line to export power to Canada.6 This is a formal permit process through the Department of Energy, Economic Regulatory Administration. It is not inconceivable that the West Creek project (and its associated export of power to Canada via the transmission line) could be stalled for some time, depending on the political appetite for such projects in Washington. Other: Opposition to the development of West Creek can be anticipated from a number of organizations, such as the Lynn Canal Conservation group (a non-profit organization that is opposes many developments in the Skagway/Haines area). There may be other organizations in both Alaska and Canada that will express concerns regarding the development of West Creek hydro, and the transmission line to the Yukon. In summary, the issues identified are not considered insurmountable. However, these issues are likely take considerable time and resources to satisfy stakeholder concerns. Project scheduling and resource planning should take this into consideration. 6 Approval to export electricity from Canada to the United States is also required under the Canadian National Energy Board Act, and is issued by the National Energy Board of Canada. - 43 - 5. REFERENCES Acres International Corporation and Chris Stethem and Associates, Ltd., 1987: Klondike Highway Avalanche Control Report. Prepared for State of Alaska Department of Transportation and Public Facilities Southeast Region. Alaska Power & Telephone Company, 2014: Preliminary Permit Application to the Federal Energy Regulatory Commission (FERC) Chris Stethem & Associates Ltd. and EBA Engineering Consultants Ltd., 1986: Klondike Highway Avalanche Atlas. Prepared for Yukon Department of Community and Transportation Services. Whistler, BC. FMS Engineers, 1983: Whitehorse – Skagway transmission line feasibility study. Prepared for Northern Canada Power Commission. Planetworks Consulting Corporation, 2014: Feasibility Study for Alternative Yukon Fiber Optic Link. Summary Report. Prepared for Department of Economic Development, Government of Yukon. http://www.economicdevelopment.gov.yk.ca/pdf/Yukon_Alternative_Fibre_Connection_- _Summary_Report_-_Final.pdf R.W. Beck and Associated Inc., 1982: Haines Skagway Region – Feasibility Study - Volume 1 – Report. Prepared for Alaska Power Authority. R.W. Beck and Associated Inc., 1983: Haines Skagway Region – Feasibility Study - Volume 4 – Supplemental Investigations. Prepared for Alaska Power Authority. Wheeler, J.O. and P. McFeely, (comp.) 1991: Tectonic Assemblage Map of the Canadian Cordillera and adjacent parts of the United states of America; Geological Survey of Canada. Map 1712A, scale 1:2,000,000 APPENDIX A: Transmission Line Concept Route Maps APPENDIX B: Development Scenarios Workshop Report APPENDIX C: Skagway-Whitehorse Interconnection System Analysis APPENDIX D: Transmission Line Design Criteria APPENDIX E: West Creek Hydro Technical Review