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Southeast Alaska Transmission Intertie Study 1987
Alaska Power Authority Sate of Alaska SOUTHEAST ALASKA TRANSMISSION INTERTIE STUDY Prepared By HARZA ENGINEERING COMPANY OCTOBER 1987 Alaska Power Authority Stove of Alaska SOUTHEAST ALASKA TRANSMISSION INTERTIE STUDY Prepared By HARZA ENGINEERING COMPANY OCTOBER 1987 Executive Summary Ne EXECUTIVE SUMMARY After reviewing demographic and economic criteria provided by the Power Authority, and the physical and hydrometerological condi- tions of the study area, Harza concludes that a transmission system interconnecting many of the Southeast Alaska communities is technically and economically feasible. Based on the planning criteria used to guide this study the most economic development would include new transmission links between (1) Snettisham and Sitka via Juneau, Green's Creek Mine, Hoonah and Tenakee Springs; (2) Petersburg, Wrangell and Ketchikan via a Tyee Lake-Swan Lake intertie; and (3) the Quartz Hill Mine and B.C. Hydro at Kitsault, British Columbia. The total estimated construction cost of these three interconnections is $153 million at the January 1987 price level. Pertinent data for the three interconnections are given in Table l. The proposed transmission links of Snettisham to Sitka and Tyee- Swan Lake appear to be the most economical utilization of the surplus generation available from the Tyee and Snettisham/Crater Lake hydroelectric developments and warrant implementation regardless of the status of the Quartz Hill Mine. Scope of Services The investigations described herein were performed for the Alaska Power Authority by Harza Engineering Company, in accordance with the terms of Contract No. APA-86-R-011. The purpose of the studies was to define the proposed Southeast Intertie Project, a transmission interconnection of Southeast Alaska's major electric load centers and hydro generation sources. Harza's studies establish guidelines for the implementation of particular segments of the transmission system in the near term, such that they would be compatible with ultimate system development. Consideration was also given to importing power and energy from the Northern Canada Power Commission (now called the Yukon Development Corporation) and/or B.C. Hydro. In order to accomplish this assignment, many tasks were performed. System studies of various intertie schemes were conducted to establish the appropriate voltage levels for the required overhead lines and submarine cables. Route selection studies for the required transmission lines were performed. These included cost comparisons and assessment of environmental impacts of alternative routes. Bathymetric surveys of potential submarine cable cross- ings were performed on numerous routes. Preliminary submarine cable and overhead transmission line engineering studies were made to select appropriate cables and overhead line structures and conductors. Finally, economic analyses of individual transmission line segments and numerous intertie systems were performed to prioritize the most feasible segments which warrant detailed investigation. Interconnections Considered The contract scope of services originally included consideration of the following transmission line interconnections: 1. Skagway - Whitehorse (U.S. portion only) 2. Skagway - Haines - Juneau 3. Juneau - Green's Creek Mine 4. Green's Creek - Hoonah 5. Juneau/Snettisham - Kake 6. Kake - Petersburg 7. Kake - Sitka 8. Tyee Lake Project - Swan Lake Project 9. Ketchikan - Prince of Wales Island (Kasaan Peninsula) 10. Ketchikan - Quartz Hill 11. Quartz Hill - Kitsault, B.C. (U.S. portion only) In response to public and agency concerns identified during meetings conducted in S.E. Alaska in January 1987, the study scope was expanded to include consideration of the following additional interconnections: 1. Hoonah - Tenakee Springs 2. Tenakee Springs - Angoon 3. Tenakee Springs - Sitka 4. Tyee Lake Project - Ketchikan (via Cleveland Peninsula) 5. Tyee Lake Project - Prince of Wales Island (via Cleveland Peninsula) Ketchikan - Metlakatla Quartz Hill - Prince Rupert, B.C. A draft of this report was completed in May 1987 and circulated among numerous interested agencies, and public and private entities. The resulting comments, along with the review comments received from the Power Authority staff, have been, to the extent possible, incorporated into this final report. Systems Studies Power system studies were performed assuming that Quartz Hill would be part of the overall system demand. These studies indicate that a transmission grid for the region should be predominantly a 138 kV AC system with direct current transmission for long submarine cable segments. The proposed system would utilize the existing Snettisham-Juneau, Tyee-Wrangell-Petersburg and Swan Lake-Ketchikan transmission lines at their present design voltage levels. Route Selection Route (corridor) selection studies were performed for 10 overland transmission line segments. The selection process included map studies, assessment of available environmental information and cost comparisons among the route alternatives. This activity was performed in consultation with the U.S. Forest Service and other public and private entities and resource agencies. In addition to the overland surveys, bathymetric surveys of 10 potential submarine cable crossing locations were performed by Harding Lawson Associates. The surveys were completed during the period October 12 through October 21, 1986. These investigations focused on locating underwater routes that would be technically and economically feasible to develop based on current technology and on bottom geometry, composition and prevailing tides and currents. Input to the route selection studies regarding the regulatory and environmental/socio/cultural aspects of the routes was provided by P.E.I. Consultants, Inc. and Northern Archaeological Consultants. Engineering Studies Preliminary engineering studies for the submarine cables were performed by Pirelli Cable Corporation. Their assignment was to select an appropriate submarine cable design for each crossing and to prepare preliminary cost estimates for the manufacture and installation of cables. Preliminary engineering studies for the overhead transmission lines were performed by Harza. The studies included line struc- ture selection, sag calculations, and conductor and insulator selection for the various AC and DC overhead lines. Cost estimates were prepared for the various lines. The most feasible overhead structure was found to be a 138 kV AC wood H-frame system with an average span length of 700 feet. The most feasible underwater cables for those segments that are longer than 25 miles in length were found to be direct current lines. Substation requirements at each line termination were assessed and cost estimates were prepared for the necessary equipment and site development. Economic Analysis Analyses of the various transmission line segments and numerous transmission system alternatives considered were performed in two steps. The first step, an economic screening, compared the construction cost of each intertie link to the value of the potential displaced diesel fuel. This was performed by comparing the net present worth life cycle costs of the intended transmis- sion link with that of the existing diesel system. Because, from a regional standpoint, the sunk cost of existing hydroelectric developments and transmission and distribution systems would be the same for all economic cases considered, these costs were excluded from both the screening analysis and the subsequent detailed analyses of the selected transmission systems. Therefore, in both analyses, the cost of power from existing Alaskan hydroelectric plants was assumed to be $0.00 per kWh for all cases analyzed. The analyses were conducted using Power Authority criteria for discount rates, energy demand, and fuel costs. The planning horizon for the study spanned 20 years. The transmission links that were found to be marginal or better on an individual basis were then included as part of the overall detailed system study. Various expansion scenarios were then tested against a base case that included no new transmission lines. Findings Following is a brief summary of some of the major findings from the study: l. The optimum system voltage for the Southeast Intertie System should be 138 kV. Direct Current (DC) transmission should be utilized for submarine cable segments exceeding 25 miles in length and also for other segments where it has demonstrated technical advantages versus AC transmission. Figure 1 depicts the lengths, optimum voltages and transmission type for the individual links of the overall system. 2. Comparison of the year 2006 load forecast with the generation capability of the region's existing hydroelectric generation facilities (including Crater Lake phase of Snettisham), reveals that without the Quartz Hill mine, the total forecast load peak and energy demand for the major load centers is less than the developed hydro capability. Without Quartz Hill, importation of energy from Canada is not appropriate during this 20 year planning horizon. Conversely, with Quartz Hill, the region's load demand exceeds its developed hydro generation capability. 3. The most economic plan investigated involves implementation, during the 20 year planning horizon, of portions of what could ultimately become a truly region-wide system. The selected transmission segments (Figure 2) would interconnect the Snettisham/Crater Lake complex via Thane substation with Juneau, Green's Creek Mine, Hoonah, Tenakee Springs and Sitka at 69 kV, and would also implement a 138 kV interconnection of Tyee and Swan Lake hydroelectric projects to intertie Ketchikan, Petersburg and Wrangell. With these segments in place by 2006, nearly all (96%) of the surplus generation available from Tyee and Snettisham/Crater Lake would be utilized. The Quartz Hill project would be independently connected to B.C. Hydro. The cost of this plan is an estimated $153 million (January 1987 price level) and its Benefit/Cost ratio is 1.26. Without the Quartz Hill line and load, the cost of the plan would be $112 million and the B/C ratio would be 1.11. The Expansion Plan B subsystems would be compatible with long term expansion to Prince of Wales Island, Metlakatla, Angoon, Kake, Skagway or Haines at such time as the load demand in those communities grows sufficiently to justify interconnection. The Plan B sub- systems are also compatible with a future interconnection of the Snettisham and Tyee Projects via Snettisham, Kake and Petersburg. If Quartz Hill receives no power from B.C. Hydro and must otherwise depend on on-site diesel generation, there would be economic advantage to providing a portion of that demand from existing surplus hydropower in Southeast Alaska. The cost of constructing the necessary transmission facilities is estimated to be $167 million in present day dollars. Figure 3 depicts the elements that would be constructed and the costs of those segments. The Benefit/Cost ratio for this plan is 1.21. The Benefit/Cost ratio associated with interconnecting Quartz Hill to B.C. Hydro with no other tie into the Alaska trans- mission system is 1.47. The cost of constructing the trans- mission line to Kitsault, Canada is estimated to be $41.3 million for the United States portion of the lines. Costs associated with the Canadian portion of the lines would be included in the wheeling price of power. Recommendations 1. A detailed feasibility study of the proposed 69 kV intercon- nection of Alaska Electric Light & Power's system on Douglas Island with Green's Creek Mine should be undertaken. The study should include a preliminary route survey, an assess- ment of foundation conditions along the proposed route, an environmental assessment, a detailed financial analysis including input from AEL&P, the Alaska Power Administration and Green's Creek Mining Company, and preparation of a definite project report. Consideration may be given to designing the line for 69 kV (to facilitate its future extension to Sitka) but operating it initially at 34.5 kV. Because the submarine cable survey conducted in 1986 indicated a feasible route, no additional submarine surveys appear to be necessary to support the detailed feasibility study of this interconnection. A detailed feasibility study of the Tyee-Swan Lake intercon- nection should be undertaken. The study should include a preliminary route survey, an assessment of foundation condi- tions along the proposed route, an environmental assessment, detailed financial analysis and the preparation of a definite project report. 3. Additional preliminary studies are required to establish the route for the Green's Creek-Sitka transmission segment. Studies performed should include comparisons of various alternative routes between the load centers, assessment of the potential environmental impacts of alternative routes and subsequent verification of proposed submarine cable crossings by side-scan sonar survey. These studies should be followed by detailed feasibility studies of the selected route including financial analysis. 4. Further assessment should be conducted on the transmission interconnection between Ketchikan and Metlakatla. An inter- connection could allow Metlakatla's diesel generators to be put into cold reserve. Detailed investigations will allow for a more definitive route assessment and refined cost estimate. 5. Future studies of individual segments should include detailed environmental studies to support final route selection, assess environmental impacts and satisfy regulatory requirements of the permitting agencies. Conclusions A level of transmission interconnection in Southeast Alaska appears prudent. Energy surpluses available from the existing Tyee Lake and Snettisham/Crater Lake projects can be utilized economically to satisfy forecast load demands in load centers not presently interconnected to these projects. As a minimum, inter- connections of Juneau and the Green's Creek Mine, in the near term, and the Tyee Lake and Swan Lake projects, in the mid-term, appear wise. Expansion of the Snettisham/Crater Lake system to Sitka or to the Quartz Hill Mine has also been shown to be economically feasible. Interconnection of Quartz Hill to Canadian generation is very attractive from an economic standpoint. Interconnection Juneau-Greens Creek Greens Creek-Hoonah Tenakee Springs-Sitka Tyee Lake-Swan Lake Quartz Hill-B.C. Hydro f, January 1987 price level. =, U.S. facilities only. Table 1 Most Economic Plan - Pertinent Data Voltage 69 69 138 100DC Initial Length Year of Estimatod Overhead Cable Total Operation Costin mi. mi. mi. $ x 1000 Zane. Siz 28.4 1990 19,690 95.3 24.0 119.3 2003 63,070 49.9 0.6 50.5 2002 29,100 24.5 25.62/ 19952/ 41,2902 3 ea Peers y Assumed commencement of mining activities. bel FIGURE 1 SKAGWAY HAINES HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG 100KV DG PRINCE ‘ LEGEND: OF WALES BIPOLAR @ - Loao centers C© - GENERATION souRcES == - EXISTING T/LINE === - PROPOSED T/LINE 13.8 - LENGTH, MILES 26.6(U.S. ONLY) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY LENGTHS AND VOLTAGES OF ROUTES FIGURE 2 . WHITEHORSE Is O SKAGWAY > —_ . C4 N, i 4 Ad, om™ HAINES @ JUNEAU HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE PETERSBURG TYEE LAKE PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS e GENERATION SOURCES KET EXISTING T/LINE CHIKAN so0KV DC (BIPOLAR). _/S 3 PROPOSED T/LINE @ QUARTZ 9 VOLTAGE METLAKATLA a COST(MILLIONS) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN B HARZA ENGINEERING COMPANY FIGURE 3 . WHITEHORSE = O SKAGWAY é “NN 7 i as ~~ HAINES @ HOONAH @ GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS PETERSBURG PRINCE LEGEND: OF WALES ISLAND @ - Loan centers e@ O GENERATION SOURCES ees - EXISTING T/LINE PROPOSED T/LINE 138KV VOLTAGE s COST(MILLIONS) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN C Table of Contents Ce ee ee es TABLE OF CONTENTS Chapter Page Executive Summary Table of Contents 1. Introduction Authorization 1-1 Purpose and Scope of Report i=1 Study Approach 1-4 Background and Previous Studies 1-5 General 1- Existing and Forecast Load Demand 1- Existing and Potential Generation Sources 1 Previous Studies 1- Acknowledgements 1-11 2s Power System Planning 2-1 Introduction System Planning Criteria System Reliability Criteria Power System Studies Power System Alternatives NNMNNN ' PND Plan I - Basic Intertie Plan Plan II - Overland North of Juneau Plan III - AC to Sitka, West Route Plan IV - Radial to Angoon Plan V - Cleveland Peninsula Other Radial Lines NNNNNN ' DADDWU AC Versus DC Transmission 2 Application of HVDC to S.E. Intertie 2-8 System HVDC Costs and Developments 2-11 Study Results 2=1112 Energy Losses 2— liz TABLE OF CONTENTS (Cont'd) Chapter So Submarine Cable Design Considerations and Cost Estimates Submarine Cable Surveys Selection of Final Cable Routes Submarine Cable Designs Submarine Cable Installation Submarine Cable Reliability Submarine Cable Costs Overhead Transmission Line Design and Cost Estimates General Climatic Conditions Structure Foundations 138 kV AC Overhead Lines Conductors Insulators Line Structures Wood H-Frame Structure Steel H-Frame Structure Single Steel Pole Structure 138 kV Line Structure Cost Comparison 69 kV Overhead Lines Conductors and Insulators Line Structures DC Overhead Lines Conductors Insulators Vertical Clearance ROW Width & Minimum Clearing Requirements Estimated Construction Cost for Overhead Transmission Lines =i Pr Sb > ' NN > > > ot ' m WW > rb Sb 1 1 1 nN Du > > 14 sn > > > 1 ooc ~ Chapter Substation Design Considerations TABLE OF CONTENTS (Cont'd) Introduction AC Stations DC Converter/Inverter Stations Local Loads and Voltages Substation Costs Communications Segment Route Selection Approach Identify Study Segments Route Selection Objectives Evaluation Criteria Physical Constraints Biological Constraints Social Cultual Constraints Costs Alternative Route Identification Data Collection and Agency Consultation Alternative Comparison and Selection HDAvoaod 1 WNN— AAA 1 CO Ul > WwW ao 1 ww a ' _ ss Segment 1:0 Skagway to Whitehorse Segment 2.0 Skagway-Haines-Juneau Segment 3.0 Juneau to Green's Creek Segment 5.0 Snettisham to Kake Segment 6.0 Petersburg-Kake Segment 7.0 Kake to Sitka Segment 8.0 Tyee Lake-Swan Lake Segment 9.0 Ketchikan to Prince of Wales Island Segment 10. Swan Lake to Quartz Hill Segment 11. Quartz Hill to B.C. Segment 12. Ketchikan to Metlakatla Segment 13. Tenakee-Sitka and Angoon Cleveland Peninsula Quartz Hill to Prince Rupert, B.C. 0 0 0 0 Green's Creek-Hoonah- 0 0 Segment 14. Segment 15. =lit= TABLE OF CONTENTS (Cont'd) Chapter Tie Economic Evaluation of Intertie Alternatives Introduction Description of Alternative Plans Alternative I - Base Case Alternative II - Southeast Alaska Connections Alternative III - Power Supplied by N.C.PsC. Alternative IV - Power Supplied by B.C. Hydro Alternative V Criteria for Economic Planning Horizon Discount Rates Economic Lives Load Forecasts Diesel Installed Costs Power Supplied by Both B.C. Hydro and N.C.P.C. Evaluation Capacity and Retirements Diesel Fuel Prices O&M Costs Investment Costs Hydro Energy Costs Methodology Screening Method Results of the Screening Northern System Central System Southern System Total S.E. Alaska Interconnection Power Supplied by N.C.P.C. Power Supplied from B.C. Hydro Power Supplied from Both N.C.P.C. and B.C. Hydro Summary -iv- TABLE OF CONTENTS (Cont'd) Chapter 7. (contd) Detailed Analysis General Energy Allocation Procedures Results of the Economic Analyses Base Case Expansion Plan Intertie Expansion Plan Intertie Expansion Plan Intertie Expansion Plan Intertie Expansion Plan Summary of Results VUAWPY, Sensitivity Analyses Sensitivity to Discount Rate Sensitivity to Fuel Price Forecast Sensitivity to Electric Load Demand Forecast Sensitivity to On-line Date 8. The Recommended Plan Description Costs Implementation Required Permits Bibliography 4-2 4-3 TABLE OF CONTENTS (Cont'd) List of Tables Title 1985 Population and Load Demand for Selected Communities High Electric Load Demand Forecast Medium Electric Load Demand Forecast Low Electric Load Deamnd Forecast Estimated Load Demand for S.E. Alaskan Mining Developments Existing Hydroelectric Projects Potential Hydroelectric Projects Load Forecast Used for Power Systems Studies Submarine Cable Routes Selected for Survey Summary of Submarine Cable Surveys Cable Designs Recommended by Pirelli Cable Corporation Insulation Dielegtric Losses for Typical 138 kV AC 240 MM“ Submarine Cable Submarine Cable Costs for Surveyed Routes Interpolated Cost Estimates for Submarine Cable Routes Not Surveyed Assumed Climatic Conditions for Overhead Transmission Lines 138 kV AC Insulator Assembly Characteristics Porcelain Vs. Polymer Insulators for 138 kV AC Construction Sag Calculations for 138 kV AC Overhead Lines -vi- 1-10 3-6 3-7 4-4 4-4 Oo ' = 1 PP KH ODIDUPWHY ~_ I DNDANDHDAADAHAA I 1 1 I dD —_ NO ~ 1 Ww 7-4 TABLE OF CONTENTS (Cont'd) List of Tables Title Page Line Structure Costs 4-6 Overhead Transmission Line Basic Construction Per Mile Costs 4-11 Overhead Transmission Lines, Per Mile Con- struction Costs in Rock and Muskeg Foundation Areas 4-11 Estimated Clearing Costs for Various Transmis- sion Line Configurations 4-11 Load Center Transmission/Distribution Voltage and Design Peak Load 5-3 Evaluation Criteria for Route Comparison 6-3 Alternative Comparison Summary, Segment 1 6.1-3 Alternative Comparison Summary, Segment 2 6.2-7 Alternative Comparison Summary, Segment 3 6.3-2 Alternative Comparison Summary, Segment 5 6.5-2 Alternative Comparison Summary, Segment 6 6.6-4 Alternative Comparison Summary, Segment 7 6.7-3 Alternative Comparison Summary, Segment 8 6.8-3 Alternative Comparison Summary, Segment 9 6.9-2 Alternative Comparison Summary, Segment 10 6.10-4 Alternative Comparison Summary, Segment 11 6.11-2 Alternative Comparison Summary, Segment 12 6.12-2 List of Alternative Systems Considered 7-3 Major Economic Criteria 7-8 Diesel Installed Capacity and Retirement Schedule 7-9 System Hydro Generation Sources 7-10 Oil and Diesel Full Price Forecasts 7-11 -vii- 7-7 7-8 7-9 7—=10 qa 7-12 1-13 7-14 7=15) 7-16 ae I=18 c-19 8-2 8-3 TABLE OF CONTENTS (Cont'd) List of Tables Title Diesel Costs Hydroelectric Project Data Transmission Line Investment Costs Screening Analysis, Energy Allocation and Costs Screening Analysis Results, Medium Load Forecast Estimated Communication System Costs Summary of Annual System Losses for Expansion Plans A, B, C and D Energy Allocation, Year 2006 - Expansion Plan C Base Case Expansion Plan, Present Worth Summary Intertie Expansion Plan A, Summary of Economic Analysis Results Intertie Expansion Plan B, Summary of Economic Analysis Results Intertie Expansion Plan C, Summary of Economic Analysis Results Intertie Expansion Plan D, Summary of Econimic Analysis Results Results of the Sensitivity Analyses Line Terminations Most Economic Plan - Summary Cost Estimate Principal Permits That May Be Required -viii- 7-18 T=22 7-22 7-24 1—25 7-26 7-27 7-29 T= 3 8-1 8-4 2 ° 2 oo 1 mWh Ww NNNNNNNNDN ND ' 1 —-OOIaAUPWDh Oo SEE Teil UO PWN > ! OV Ua ' t-4 Wh a aoa ' ' w Nn oy ' w wy oO | cS 6-5 TABLE OF CONTENTS (Cont'd) List of Figures Title General Map Existing Transmission Lines Existing Hydroelectric Plants Potential Hydroelectric Plants Plan I - Basic Intertie Plan Plan II - Overland North of Juneau Plan III - AC to Sitka, West Route Plan IV - Radial to Angoon Plan V - Cleveland Peninsula Plan I - System Plan II - System Plan III - System Plan IV - System Plan V - System Surveyed Submarine Cable Routes 138 kV AC Wood H-Frame Tangent Structure 138 kV AC Steel H-Frame Tangent Structure 138 kV AC Steel Pole Tangent Structure 69 kV AC Wood Pole Tangent Structure Monopolar 100 kV DC Wood Pole Tangent Structure Minimum Clearing Diagram 138 kV Structure Typical 138 kV AC Main Line Substation Typical Radial Line Substation, Converter Station Main Components Typical Bipolar Converter Station Segment Designations Route Alternatives, Segment 1, Skagway- Whiterhorse Route Alternatives, Segment 2, Skagway- Haines-Juneau Route Alternatives, Segment 2, Skagway- Haines-Juneau Route Alternatives, Sgement 3, Douglas Island-Green's Creek Route Alternatives, Segment 5, Snettisham- Kake -ix- TABLE OF CONTENTS (Cont'd) List of Figures No. Title Page 6-6 Route Alternatives, Segment 6, Petersburg-Kake 6.6-4 6-7 Route Alternatives, Segment 7, Kake-Sitka 6.7-3 6-8 Route Alternatives, Segment 8, Tyee-Swan Lake 6.8-3 6-9 Route Alternatives, Segment 9, Ketchikan- Prince of Wales Island 6.9-2 6-10 Route Alternatives, Segment 10, Swan Lake- Quartz Hill - B.C. 6.10-4 6-11 Route Alternatives, Segment 11, Quartz Hil1l-B.C 6.11-2 6-12 Proposed Route, Segment 12, Ketchikan- Metlakatla 6.12-2 6-13 Proposed Route, Segment 13, Tyee-Ketchikan- Prince of Wales Island Via Cleveland Peninsula 6.13-4 6-14 Proposed Route, Segement 14, Green's Creek- Hoonah-Tenakee Springs-Angoon-Sitka 6.14-3 6-15 Quartz Hill-Prince Rupert Submarine Calbe Routes 6.15=2 6-16 Length of Selected Routes 6.15-2 7-1 Geographic Sub-Systems 7-1 7-2 Routing Alternatives 7-2 7-3 Alternative I - Base Case 7-6 7-4 Alternative II - S.E. Alaska Connections 7-6 7-5 Alternative III - Power from N.C.P.C. 7-7 7-6 Alternative IV - Power from B.C. Hydro 7-7 7-7 Alternative V - Power from N.C.P.C. and B.C. Hydro hai 7-8 Expansion Plan A 7-21 1-9 Expansion Plan B 7-21 7-10 Expansion Plan C 7-21 7-11 Expansion Plan D 7-21 8-1 Most Economic Plan 8-1 Appendix A - Appendix B - Appendix C - Appendix D - List of Appendices Southeast Alaska Intertie Project Submarine Crossing Surveys, Skagway to Ketchikan, Alaska. Harding Lawson Associates, Novato California. December 31, 1986. Pirelli Cable Corporation. "Comments on Southeast Alaska Intertie Bathymetric Survey Conducted During the Period of October 13-31, 1986". Capt. Antonio Nesi, author. December 1986. and "Pirelli Report on Participation in Southeast Alaska Intertie Study", with Societa Cavi Pirelli. March 20, 1987. Northern Archaeological Consultants, Inc. "Cultural Resources Along the Route of the Proposed Southeast Alaska Intertie Project". April 1986. Public and Agency Contacts Report Chapter 1 INTRODUCTION Authorization This study was performed in accordance with the terms of Contract No. APA-86-R-011, (and its Amendment No. 1) between the Alaska Power Authority and Harza Engineering Company. Funds for the study were provided by the State of Alaska. Purpose and Scope of Report As shown on Figure 1-1, there are presently, in the South- east Alaska archipelago, many electrically isolated communities, each with its own generation facilities for electric power. For many load centers the only generation facilities are diesel- electric generators. Others have developed hydroelectric resources to meet their load demand and in many cases have sur- plus hydroelectric capacity. Interconnection of the load cen- ters by an electric power transmission system would allow the interchange of surplus hydroelectric energy by load centers which would otherwise be dependent on fossil fuel generation. The interconnection would also allow more efficient development of Southeast Alaska's abundant hydroelectric resources and could also facilitate the utilization of surplus Canadian hydrogenera- tion by interconnection with the Northern Canada Power Commis- sion (now called the Yukon Development Corporation), through Skagway, or with B.C. Hydro to the south. Over the years, the Alaska Power Authority, the Alaska Power Administration, and others have studied the feasibility of transmission interconnections between specific generation faci- lities and one or more load centers. Three of these transmis- sion lines, which could form the backbone of a Southeast Alaska Intertie System, have already been constructed. These are the 138 kV Snettisham Project transmission line, serving the Juneau area; the 138 kV Tyee Lake Project transmission line, serving Wrangell and Petersburg; and the 115 kV Swan Lake Project trans- mission line, serving Ketchikan. See Figure 1-2. In 1985, there were 44 circuit miles of 138 kV, 30 circuit miles of 115 kV and 121 circuit miles of 69 kV transmission lines in the Southeast Alaska region. Of the 44 miles of 138 kV lines, about 15 miles are submarine cable. However, as indicated by the variation in voltage levels among the existing lines, there is a need for the establishment of criteria to guide the development of future transmission line segments to insure their compatibil- ity with the proposed overall Southeast Alaska grid. The purpose of this study is to provide those required criteria. 11 FIGURE 1-1 137° 136° 135° 134° 133° 1320 ime 10° ." T T T Tv T e Load Center ; ; ° Whitehorse el] LEGEND ' ° Generation Source —— Existing Transmission Line GULF OF ALASKA Note: Base map taken from USDA Forest Service General Technical Report PNW - 66,1978 o 6 3% 4s 56oe 55°p ' 1 1 L 137° 136° 138° 134° 133° 32 131? 130 ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY GENERAL MAP WHARZA Encineeanc comecny | OCTOBER 1967 FIGURE 1-2 GVEA GVEA 345 KV J—69/345 KV _ Foirbanks GVEA on =) i - Nort pat Pole aan EXISTING TRANSMISSION SYSTEMS Scale in miles 100 (Map taken from Alaska Electric Power Statistics, 1960-1984, Aiaska Power Authority, December 1985. 30PP) The scope of this study includes the following work tasks: Task No. 1. Task Description Collection and review of existing data including topographic maps, bathymetric and navigation charts, aerial photographs and previous reports. Preliminary route selection to establish macro- corridors for transmission intertie segments and establishment of primary and alternate submarine cable routes to be surveyed. Underwater surveys of submarine cable routes culminating in a survey report containing bathy- metric profiles of the routes surveyed and iden- tifying potential impediments, if any, to cable installation, such as unstable sediments, obstacles, strong currents and busy navigation channels. Preliminary engineering investigations including, for submarine cable crossings, selection of cable voltage, cable type, cable installation pro- cedures and locations of cable termination points, and for overhead transmission lines, selection of not more than two routes with in the macro-corridor, selection of appropriate voltage, conductor, and structure type. Environmental investigations, including investi- gations of potential impacts, if any, on land use and cover, recreation, and visual, cultural fish- eries, terrestrial and other resources; contact and coordination with the U.S. Forest Service, other appropriate Federal and State agencies and affected local government, utility and Native corporation entities; and determinations of the required permits and authorizations required for implementation of the intertie segments. Engineering studies to determine an ultimate intertie system for Southeast Alaska, including the establishment of planning criteria and equip- ment capacity ratings considering load data, load flow and sequential implementation of the trans- mission line segments; and the preparation of cost estimates for engineering and construction of the transmission lines. l=2 7. 8. Economic analysis of the transmission line seg- ments, including comparison of the lines to a base case expansion plan; and priority ranking of the segments on the basis of economics, need for power in the load centers served, environmental impact and constructibility. Preparation of the study report. Originally, the study was to examine interconnection of the following: 10. 11. Skagway - Whitehorse (U.S. portion only) Skagway - Haines - Juneau Juneau - Green's Creek Mine Green's Creek - Hoonah Juneau/Snettisham - Kake Kake - Petersburg Kake - Sitka Tyee Lake Project - Swan Lake Project Ketchikan - Prince of Wales Island (Kasaan Peninsula) Ketchikan - Quartz Hill area Quartz Hill - Kitsault, B.C. (U.S. portion only) The study was subsequently expanded to include consideration of the following interconnections: Hoonah - Tenakee Springs Tenakee Springs - Angoon Tenakee Springs - Sitka Tyee Lake Project - Ketchikan (via Cleveland Peninsula) Tyee Lake Project - Prince of Wales Island (via Cleveland Peninsula) 6. Ketchikan - Metlakatla Ws Quartz Hill - Prince Rupert, B.C. Study Approach The tasks described above were executed, with the assist- ance of Power Authority personnel, by Harza and its four subcon- tractors, Harding Lawson Associates (Anchorage), Northern Archaeological Consultants, Inc. (Anchorage), PEI Consultants, Inc. (Ketchikan) and Pirelli Cable Corporation (Union, New Jersey). The responsibilities of the participants were as follows: e Harding Lawson Associates performed the surveys of the submarine cable routes, collected and reviewed data pertaining to the routes, participated in the pre- liminary selection of the cable crossing locations, analyzed the survey data collected and prepared the survey report which is included as Appendix A. Sub- contractors to Harding Lawson Associates in this effort were Gregco, Inc., which furnished navigational services, and Robert D. Horchover, whose M.V. Silvia J. served as the vessel for the surveys. e Northern Archaeological Consultants, Inc. performed cultural resources investigations of the proposed tranmsission line routes. The resulting report is included as Appendix B. e PEI Consultants, Inc. was responsible for data collec- tion and served as the principal point of contact with the resource agencies and affected public and private entities. PEI prepared the list of required permits and authorizations presented herein and organized and participated a round of project status meetings with public, private, and agency groups throughout South- east Alaska in January, 1987. e Pirelli Cable Corporation performed preliminary cable engineering services including participation in the preliminary cable crossing selection, review of the survey report, cable design selection and preparation of the cost estimates for engineering, manufacture and installation of submarine cables for the surveyed routes. Pirelli also provided the services of a submarine cable installation expert as an onboard observer during the survey task. e Harza Engineering provided overall coordination and project management for the study and participated, in all of the work tasks. Specific tasks for which Harza was solely responsible included power system studies of the various intertie configurations consid- ered, establishment of the study planning criteria, review of previous reports, voltage selection, over- head transmission line and substation engineering and cost estimating, environmental assessment, economic analysis and priority ranking of the routes, and pre- paration of the study report. e Alaska Power Authority provided pertinent reports, electric load forecasts, land and land rights costs, oil price forecasts, costs of Canadian and Alaskan generation and participated in the submarine cable surveys and the January 1987 project status presenta- tions. The study was performed in two phases. Phase 1 included Tasks 1 through 5 and culminated in the preparation of cost estimates for numerous transmission line segments and combina- tions of intertied systems and a preliminary economic screening to eliminate those transmission line segments or systems not warranting further study. Phase 2 included Tasks 6 through 8 and involved refinement of the cost estimates for selected routes, detailed economic and sensitivity analysis, the priority ranking of the recommended individual transmission line seg- ments, and confirming power system studies. Background and Previous Studies General Southeast Alaska lies along the Pacific coast of the North American continent, generally east of the 141st meridian and south of the 60th parallel. The climate is maritime; mild and moist at the lower altitudes with warming provided by the Alaska Current. With increasing altitude the climate becomes more severe with heavy snowfalls at upper altitudes resulting in the formation of numerous glaciers and several ice fields. Precipi- tation accumulation ranges from between 60 to 200 inches per year with steady, light to moderate rainfalls or snow occurring on 200 to 250 days per year. The economy of the area is based upon government services, the fishery and forest products industries and to a lesser extent on mining and tourism. While recent events and depressed markets have caused a decline in several important sectors of the region's economy, there are prospects for increased activity 1=5) in the mining and tourism sectors, as well as the forest products industry. Transportation through the area is diffi- cult, depending on the Alaska Ferry System and air services. Roads systems are mainly local, in the vicinity of the region's larger communities, with the exception of the fairly extensive road network on Prince of Wales Island. Roads through Canada via Skagway, Haines or Hyder provide the only access to outside highway systems. The population of Southeast Alaska, while exhibiting a general upward trend, tends to fluctuate with the local economy, particularly on a community by community basis. Table 1-1 gives recent population figures for selected communities in the region. As shown in the table, Juneau, the State capital, has the largest population, followed by Ketchikan, Sitka, Petersburg and Wrangell. Table 1-1 1985 POPULATION AND LOAD DEMANDS FOR SELECTED COMMUNITIES Community Population Peak Demand Ener Demand (kW) (MWh) Skagway 800 1,200 4,829 Haines 1,800 1,668 8,685 Juneau 28,940 57,700 261,189 Kake 630 7,200 20,294 Sitka 8,200 14,738 105,003 Petersburg 3,250 5,000 27,547 Wrangell 2,400 3,270 13,651 Ketchikan 13,200 25,500 108,422 Metlakatla 1,423 7,200 20,274 Craig 1,167 1,158 4,137 Klawockl/ 590 411 1,741 Thorne Bay/ 430 229 1,104 Hydaburg1 395 289 1,152 1/ 1984 Estimates from the "Black Bear Lake Hydroelectric Project Feasibility Report Update". Harza Engineering Company, February 1987. 1-6 Existing and Forecast Load Demand Estimates of present and future electric load demand in Southeast Alaska were furnished by the Alaska Power Authority. In addition to population data, Table 1-1 gives peak and energy demands in selected S.E. Alaska communities. Three forecasts of future load demand were provided. As shown in Tables 1-2 through 1-4, the total forecast energy demand for 15 load centers ranges from a low of 875 GWh in year 2006 to a high of 1,496 GWh in that year, with cumulative peak load demand ranging from 182.1 MW to 320.4 MW for the same load centers. The medium load forecast for the load centers, for the year 2006 is 1,534,000 MWh and 211.2 MW. Table 1-2 HIGH ELECTRIC LOAD DEMAND FORECAST ENERGY DEMAND (MWh) 1987 1988 1989 1990 1991 1992 1993 1996 1995 1996 1997 1998 1999 2000 2001 2002 2003 2006 2005 2006 Hee HEHE sae sa soe sau sae see sae sete sa sae sete Hee Hoe se sae we aoe Skagway S420 5,650 5,890 6160 6006457618 657861637) 700s 758 B16 = B7S 93K 99% 705K IS 17H 72387300 Haines 8917 95035 «99155 95277 KOD 517 = 9636 = 9756 = 97877) 10,000 10,087 10,174 10,262 10,351 104460 10,531 10622 10,714 10,606 10,900 Green's Creek 0 0 O 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 26,061 265061 26,061 Juneau 758,700 256,600 262,400 268,500 272,600 277300 261,900 266,500 271:400 293,200 295,600 297,700 299,700 301,800 304,800 307,800 310,800 313,900 317,000 321,000 Hoanah 2,821 3,018 = 3,230 3456 3678 3,957 236 S30 TLL 49005096 50279 SSML 547325961 199 847 70S HyF7H 74259 Kake 2:77 2,853 2,933 3,016 3100 3,158 3,217 3,277 «93,338 3,600 = 3,504 = 361235723 3,837 35955 4076 4201330 hb3 4 B00 Sitka 106,113 106,989 109,943 112,980 116,100 120,270 124,587 129,063 133,678 138,500 163,365 146,400 153,612 159,007 1641592 170:373 176,357 182,551 168,963 195,600 Angoon 1,688 91,592 1,708 =1823. 1,950 92,087 2,233) 2,387) 2468S 2586 268825795) = 25907 «93502335164 = 35270) 3401 = 35537 = 3678 = 3826 Tenakee 270 30S 322 39 31 33 1b 389 403 417 431 446 462 478 495 $12 $30 949 968 $88 Petersburg 27,716 30,560 31,180 31,633 32,500 33,0978 33,706 34,326 34,957 35,600 9 36s253 36919 37,596 = 385286 © 38989 395706 40433 41,175 41,931 42,700 Urangel! 19,476 19,963 20,463 20,975 21,500 21,906 22,317 22,736 923,164 = 23,600 926,066 9245562 251027 25521 26,025 26560 27,064 9275599 9281144 = 28, 700 Ketchikan 125,257 137,336 154,997 172,420 191,800 203,156 215,180 227,918 241,407 255,700 262,099 2681658 275,382 282,273 289,33? 2761578 304,000 311,608 319,407 327,400 Quartz Hill 0 a 0 a Q 199,750 250,300 250,300 250,300 453,200 475,600 476,100 476,100 476,300 476,300 476,200 476,200 476,200 476,200 476,200 Prince of Wales 12,818 13,964 15,177 16,529 18,011 191638 20,987 22,438 26,002 + 25,687 27,503 28,822 30,206 31,657 33,180 34,778 936,455 385214 940,060 941,997 Metlakata 20:258 20616 = 20576 = 205737 20,900 211096 = 21296 = 21696 2169 = 21900221279 2266S 23,057 923,456 = 23862 24,275 24,695 25,123 25,558 26, 000 PEAK DEMAND (kU) Skagway 1,400 1,400 1,600 = 1,400) = 1,400) 1419154371457 15679 1HSDD S10 1051915527 1537 SKF 155571567 15577 15570 1,600 Haines 1638 15677) 1571715758 180018201839 185918801900 91K 1092719661957 97H 1987-2006 = 25019 2034 = 2,050 Green’s Creek 0 0 0 3,500 3,500 3,500 3,500 3500 3,500 3,500 3,500 3,500 3500 3,500 3500 3,500 3,500 3,500 3:500 3,500 Juneau 561600 56,200 $7,400 58,700 59,700 40,700 61,800 42,800 63,800 64,200 66,700 65,200 465,600 6,100 66,800 67,400 68,000 68,700 49,400 78,300 Hoonah 675 722 773 827 885 96715013 10B4 1127 02731209 126B 1319 1372 1h27 1 6BA 155631605 16691573 Kake 679 698 118 139 160 m 79S 813 31 850 875 900 2b 953 980 = 15008 391,037 1,067 1,098 = 1,130 Sitka 16,060 16,705 17,376 16,074 18,600 19,576 20,379 215218 22,091 23,000 23,917 26,870 25,861 926,892 27,964 §=27,079 9305238 31,443 = 32,697 = 34,000 Angoan 431 461 493 $28 S65 604 647 692 720 748 778 609 862 876 WL 947 985 = 1,026 =15065 = 1,108 Tenakee 1h n 62 86 89 2 si) 9 102 106 109 113 117 121 126 130 134 139 144 149 Petersburg 5715 5,833 5,953 6,075 bs200 S316 = sh33— SSF b76 BOD 7207106274166 7529374227853 768K 7,821 7,960 = BF LOU Wrangell 40077 4995 45235317 MDD 677556 636 4717 BOD B75 SD 55027 S105 18S 55265 5347 = 54305514 = 5600 Ketchikan 26052 28516 31,214 346,167 37,400 40,251 43,317 46,621 90,175 «96,000 995,530 57,102 $6720 605383 62,093 63,852 651661 7,521 49433 71,400 Quartz Hill 0 0 0 0 0 50,000 50,000 50,000 50,000 95,000 95,000 95,000 95,000 95,000 95,000 95,000 95,000 5,000 95,000 95,000 Prince of Wales 3060 3,360 3695S) 4069 4894961 = 5346 9 76B 2317417302761 7097S 33S BTLL = 7/106 7/518 = 97950 = 10403 10876 Metlakata 6:2597 6318 63781437 = SOD 59769796 = BI? 700071627328 7K97— 7671 = 7849 = 80308216 = B40 = BOL = 8 BOD Table 1-3 MEDIUM ELECTRIC LOAD DEMAND FORECAST 1987 1968 1989 1990 1991 1992 1993 1996 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 sone Jan s00E 1H Jane sae 100 20H 10H 1000 100 sae sH0e Hoe sau sao sa sae ee ee Skaquay 51369 55563 55723 5,908 100120160160) 1BDbs200 12275259 287318 36K 437B 6409639447 4S Haines 6677) 8958 9038 95119) 920095257 319953799437 SDD 756B 9636 70S) 77K BAK 75916 = 9798S «10056 9 105128 10,200 Green’s Creek 0 0 0 26,061 26,061 26,061 26,061 26,061 26061 926,061 9 261061 926,061 = 26061 = 26061 = 26061 §=— 26061 §=— 26061 = 26061 = 26061 = 26, 041 Juneau 2645300 256,800 254,400 255,300 258,300 257,900 260,700 261,500 262s300 263,500 264,400 265,200 266,000 266,900 267,800 2685700 269,500 270,400 271,200 272,400 Hoonah 2,821 25970) 351273529236’ 3649 3842 04S 4517S 430767? 45904738 48905067 = S5209 995376 569 = SV 71S SSBB? Kake 2,637 2678 2,718 2,757 = 2,800) 2,837) 92,878 = 2,918 = 2595? = 3,000) 3,047 «93,098 = 3162 31913260) 35271 3362) 3537K 3446 3,500 Sitka 102,580 103,661 105,158 106,471 107,600 110,081 112,411 1145790 117,219 119,700 122s110 126,568 127,075 129,633 132,263 134,905 137,621 140,391 143,217 146,100 Angoon 15686 15567) 1565115739 1832) 15930) ©2033) 2s041 = 25210 252812356 2430 2,508 = 2,588 92567125757 = 2B4E 25937 = 350253 118 Tenakee 282 289 296 304 U2 uy 327 336 34s 383 Jot 370 380 389 399 409 419 429 440 451 Petersburg 29,527 295961 30,401 30,867 31,300 931,670) 932,085 = 32485 = 32,890 933,300 933,707 934119 = 341536 = 345958 35,385 «351817 = 361255 341678375146 = 375600 Wrangell 19,167 19,500 19,860 205227 20,600 = 20,856 = 21110 215370 21636 = 215900 22,174 = 22,452 22732-23017 = 234305 23597 23,892 9 2hs191 «= 24494 = 24, B00 Ketchikan 117,268 123,446 129,969 136,796 144,000 147,685 151,674 155,971 160,177 164,500 167,045 167630 172,255 1745920 177626 180,375 183,166 186,000 188,878 191,800 Quartz Hill 0 Q 0 0 0 a 0 Q 199,750 250,300 250,300 250,300 250,300 250,300 250,300 250,300 250,300 250,300 250,300 250,300 Prince of Wales 115656 125231 12,839 13,477 14,153 14,863 15,338 = 15,827 916336 «16859 17,400 175970 185560 = 195169 = 195798 20469 = 214122 21,817 225536 = 23,280 het lakata 205199 = 205299 = 205399 20,4699 20,600) «205717 «= 20,838 = 20,958 21,079 «21,200 21,518 921,840 22,167 922,500 9 221837 923,177 9235526 923,879 9241237 = 24,600 PEAK DEMAND (kW) Skagway 1,400 1,600 = 1,400) 1400) 1,400) 1,600) 1,600) 1,400) 24001400) 1410 141915627 1639 1hhF14SF 156691479 14901500 Haines 1620 1,637 1,657 1,680 1,700 1,720) 1737) 1,759) 1,780) 1800) 181016201827) 18391869) 185915867 188018901900 Green’s Creek 0 0 0 3500 3,500 3,500 3,500 3,500 3,500 3,500 3,500 3500 3,500 3,500 3500 3,500 3,500 3,500 3,500 3,500 Juneau $7,900 56200 55,700 95,900 96,500 96900 57,100 $7,200 57,500 57,700 $7,800 $6,100 58,200 S4,S00 58,400 58,800 57000 57,200 57,400 59,400 Hoonah 687 721 758 196 836 878 922 968 998 = 1029 1060) = 109327201 1519715238 0272, TL 13501391 Kake 660 670 680 670 700 710 720 730 740 750 760 m7 781 192 803 614 825 837 848 860 Sitka 150777 160121 16473 16,833 17,200 17,637 18,086 18545 19,017 19,500 19950 205411 205882 215366 = 21857 225362 22,878 923,407 9235947 += 24,00 Angoon 440 462 485 $10 S38 S62 $90 620 639 658 678 699 720 742 Tbh 787 611 836 841 687 Tenakee nN B i) n qv 81 83 85 87 89 92 % % 9 101 104 106 109 112 114 Petersburg 5597 5.695 5,795 589% 6,000 6,057 6,118 65178 6237 6300385 bh 71 SS? 66 73S) 82H 17? 7010 7104 = 7,200 Wrangell 35977 6s055 13S 21730044337 379 1F WSF SOD S68 41S96 BBS 4694 MHS 45796 BAA 4 B96 45948 = 8,000 Ketchikan 29,003 26,487 26,066 29,732 31,500 32,600 933,739 934,918 = 36138 © 37,600 = 38,021 9 384653 39,275 39,948 40612 = 41,287 41,973 42670 45379 46,100 Quartz Hill 0 0 0 0 0 0 0 0 50,000 50,000 50,000 50,000 50,000 50,000 50,000 50,000 50,000 S0,000 50,000 50,000 Prince of Wales 2,630 3,001 3,166 3,382 3596 = 3828 3925) 45026 ASL 452383696 S87 TLL 48374970105 5244 5387 S536 Metlakata 6400 6,400 = 40064006400) 6459) = y51B 578 6637 = TDD B37 97H 741197264 7412745637718 787S B36 = 8 200 Table 1-4 LOU ELECTRIC LOAD DEMAND FORECAST ENERGY DEMAND (MWh) 1987 1988 1989 1990 1991 1992 1993 1996 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 JHE JHE JOHbe JOE SHOE JAH see sae Jae sae Je JH 1H Jae Hoe TH sae JOH 1000 10 Skagway 5:239 50277 S319? = 838? = KDD = 55252 S108 4968 = B32 4 0D 70D 700 4 700 4 700 700 4 700 4 700 4700 4, 200) 4, 700 Haines 6760 8,777 6619 6660 8900 8900 8,900 6,900 6900 8,700 6910 8920 6,930 6740 6950 6960 6970 6980 6990 9,000 Green's Creek 0 0 O 26,061 26061 = 26,061 26,061 26,061 = 26,061 9 261061 = 26,061 = 261061 = 26,061 = 26061 = 26s 061 = 26061 = 261061 += 26061 ~=—26s061 +26 Dt Juneau 266,300 256,800 253,100 250,400 250,100 250:500 251,100 251,600 252s200 253,000 253,200 253,400 253,500 253,400 253,800 253,900 254,000 254,100 254,300 254,800 Hoonah 2,621 25906 = 25993, 35083) 35175) 3527035368 3467 = 35537) = 361036823755 3583135907 «= 3598S 06S 4166 45227 314 OO Kake 2,600 2.600 2,600 2,600 2,600 2,600 2,600 2,600 2,600 2,600 2600 2600 2,600 2,600 2,600 2,600 2,600 2,600 2,600 2,600 Sitka 1015131 100,948 100,765 100,582 100,400 101,032 101,668 1025308 102952 103,600 1065097 106,600 105,104 105,611 106,119 106,631 107,144 107,660 108,179 108,700 Angoan 1,468 = 15533, 1057915626 1b7S 15725) 5777) 1830 18H? 190K 1962 19BL = 20212061 = 20022866 = 25187 = 252381252752 2A Tenakee m 280 282 28S 288 271 294 27 300 303 306 310 33 316 319 322 325 329 332 335 Petersburg 29236 277,478 271429956 = 30200» 30,397 30596 = 3079 = 30997 9 34200 9 3138S 315571 31,758 310967 = 325136 = 32326 32,518 = 32,711 = 32,905 33,100 Vrangel | 17,957 17,336 165737 16159 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 15,600 Ketchikan 113,709 1175330 121,067 1265922 128,900 130,671 132,465 134,285 136,130 138,000 137,358 140,730 142,115 143,514 166,926 146,353 147,793 149,268 190,717 152,200 Quartz Hill 0 0 0 0 0 0 0 0 0 0 0 0 O 199,750 2505300 250,300 250,300 250,300 250,300 250,300 Prince af Vales 10/697 10,973 14256 11,566 1LB4L 125147 12,648 125757 135073 13,398 13,731 14,051 145379 1471S 15,057 15412155772 1b 141 = 16519-16906 Het lakata 20,020 20,040 20,060 20,080 20,100 20,120 20,140 20160 20180 20,200 20240 20,279 20,319 20,357 920,397 = 20,437 = 20,477 = 20,519 20,560 += 20,400 PEAK DEMAND (kW) Skagway 1,600 = 1600 15600 15600) 1560015336272 121111S6 1100100010001 100 1100) 110010001100) 1,100) 1,001, 100 Haines 1,620) 15637) 1,659) 1,680) 15700) 1,700) 1,700 1,700) 1700) 1,700) 1700 1,700) 1700) 1570015700 1,700) 1,700 15700) 1,700) 1,700 Green's Creek a 0 0 3,900 3,500 3,500 3,500 3,500 3,500 3,500 3500 3,500 3,500 3,500 3500 3500 3,500 3,500 3,500 3,500 Juneau 57,900 S6s200 55,400 54,800 54,800 54,900 55,000 55,000 55,200 55,400 S5,400 55,400 55,500 55,600 55,600 55,600 55,700 55,700 55,700 S5600 Hoonah 675 695 716 738 760 783 604 630 847 B64 681 899 WN? 935 954 913 992 «10012 1,032 1,053 Kake 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 640 Sitka 15,511 15,983 15,655 15,727 19,800 19,918 16,037 16,157 16,278 16,400 = 165497 16)59S 16678 = 164793161893 16,993 17,098 = 1719S 17,297 17,400 Angoon 431 446 457 47 48S 500 S15 530 S41 S51 562 S74 S85 597 609 621 633 646 659 672 Tenakee 70 a 2 nN 2B 74 7S s 1b 7 18 W 7 60 81 62 83 83 64 85 Petersburg 5557 $618 5.678 5,737 5,800 5,620 5,840 5,660 5,680 5,900 5/937 5,978 6017 6057 = 6097-13717? 62186259 300 Wrangell 37% = 3,692, 3,592) 3,495) 3,400 = 3,400) 3,600 3,600) 3,400) | 3,400) 3,600) 36003400) 3,400) 3,600) 3,400) 3,600 3,400 )= 3,400) 3,400 Ketchikan 24155 25.061 = 25,960 26913 27,900 9285327 28,760 §= 29,200 291647 «= 30100 930433 30770) 31110 9 31,4654 = 31,802 32,154 = 32,507 = 32869 = 335232 33,400 Quartz Hill Q 0 q a 0 0 0 0 a 0 0 0 Q 90,000 $0,000 50,000 50,000 50,000 50,000 50,000 Prince of Wales 20467 = 2,520 25575-25632, 2689 2,769 281225876 25962) 3,010 3,077 3146 3216 35283 3,355) 34283502 = 3,578 = 3656 = 3,736 Metlakata 6120 © 6140160180) 6200200200 200200200 2201239) 259279299 FNF— 339 =H ISF =H 380 4 4 Table 1-5 shows estimated load demand of two mining developments in Southeast Alaska. As shown on the table, the Green's Creek Mine, on Admiralty Island, is estimated to have a peak demand of 3.5 MW and an energy demand of 26,060 MWh for a 20 year duration beginning in 1990. The Quartz Hill Mine, located east of Ketchkian, is assumed to have a peak demand of 50 MW and an energy demand of 199,750 MWh beginning in 1995 increasing to 250,000 MWh by 1996. Table 1-5 ESTIMATED LOAD DEMAND FOR S.E. ALASKAN MINING DEVELOPMENT Average Estimated Mine Peak Demand Annual Ener Project Life (kW) (MWh) (years) Green's Creek Mine 3,500 26,060 20 Quartz Hill Mine 50,000 250,000 50 Existing and Potential Generation Sources Southeast Alaska has abundant potential hydroelectric resources. Table 1-6 lists the major existing projects and gives their installed capacity and estimated average annual energy output. As shown-on the table, the total existing hydro- electric generating capacity in Southeast Alaska is 173.6 MW; the total average annual energy output of the projects is 794,290 MWh. Figure 1-3 shows the locations of the existing hydroelectric plants. Many potential hydrolectric developments have been studied. Table 1-7 lists several projects which continue to be given serious consideration and shows the estimated installed capacity and projected average annual energy output of each. Figure 1-4 shows the location of these projects. 1-8 137° 136° 135° 134° FIGURE 1-3 133° 1370 1319 130° T s9° GULF OF ALASKA | | | | Note: r ° = Base map taken trom USDA Forest Service General Technical Report PNW - 66,1978 ° 1$ 3048 cale Mies | 55° G Map Area” — T T T T LEGEND e Load Center A Generation Source —— Existing Transmission Line rl Tyee Lake Dt Dixon Entrance 137° 136° 138° Reter to Table 1-6 for Project Name, Capacity and Average Annual Energy Generation. HARZA encineeRnG COmPaNy- OCTOBER 1987 1340 133° 132° 131° 130° ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXISTING HYDROELECTRIC PROJECTS FIGURE 1-4 s7° 55°p 1370 136° 135° 134° 133° 1320 131° 130° = T T 7 T T T ° whritenorse pe LEGEND GULF OF ALASKA Note: Base map taken from USDA Forest Service General Technical Report PNW - 66,1978 © | 36 | 90:| 45 Taare Miles ALASKA 1 e Load Center ° Generation Source — Existing Transmission Line A Potential Hydro Project 4 s7° ") Lees \ \ ~ ee —_—- Dixon Entrance HARZA EncineennnGc company - (Bem eprecid Det rarer ial eee ioe eee eee 137° 136° 135° 1340 Refer to Table 1-7 for Project Name, Planned Capacity and Average Annual Energy Generation. OCTOBER 1987 133° 1320 131° 132° ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY POTENTIAL HYDROELECTRIC PROJECTS Table 1-6 EXISTING HYDROELECTRIC PROJECTS Installed Capacity Avg. Annual Project MW Energy MWh 1. Skagway, AP&T Hydro 1.0 2,940 2. Juneau, AEL&P Hydro 10.6 60,000 3. Snettisham 46.0 216,000 4. Crater Lake 27.0 118,000 5. Sitka, SED Hydro 20.05) 103,000 6. Petersburg, MP&L Hydro 20) 10,000 7. Tyee Lake 20.0 114,100 8. Swan Lake 22.5 85,400 9. Ketchikan, KPU Hydro 14.0 62,700 10. Metlakatla, MP&L Hydro 4.01/ 22,1501/ Total 173.6 794,290 WA Includes planned Chester Lake Hydroelectric Project. t=-9 Table 1-7 POTENTIAL HYDROELECTRIC PROJECTS Avg. Annual Project Capacity, MW Energy MWh 1. West Creekl/ 4.5 20,210 2. Takatz Lake2/ 27.3 93,200 3. Black Bear Lake3/ 3.0 17,600 4. Lake Dorothyl/ 26.0 127,000 5. Sweetheart Lakel/ 26.0 125,000 6. Tyee Lake Expansion4/ 10.05/ 22,4005/ 1/ Haines-Skagway Region Feasibility Study, R.W. Beck, 1982. Qf: City of Sitka Alternative Energy Study, Ott Water Engineers, Inc. 1982. 3/ Black Bear Lake Project Feasibility Report Update, Harza Engineering Company, 1987. 4/ Definite Project Report - Tyee Lake Hydroelectric Project, International Engineering Company, Inc., 1979. S/ Incremental capacity and average annual energy. Bordering Southeast Alaska, to the east and south, is the Canadian province of British Columbia. The provincial utility, British Columbia (B.C.) Hydro, is one of the largest owner/ operators of hydroelectric generating facilities in the world. The utility has over 9,000 MW of installed hydrogeneration capacity at the present time and has identified several other major projects which could be developed. Assuming a favorable long term agreement could be reached with B.C. Hydro, Canadian generation could be imported to satisfy Southeast Alaska's power and energy requirements for the forseeable future. Such an arrangement would require the construction of a transmission interconnection of the B.C. Hydro grid with a Southeast Intertie System in the Ketchikan/Swan Lake area. 1-10 Surplus Canadian hydrogeneration of a lesser magnitude is also available from the Northern Canada Power Commission (N.C.P.C.) in the Yukon Territory. Importation of generation from this source would be via a Whitehorse-Skagway transmission line. Either of these alternatives would require a Federal Energy Regulatory (FERC) license, an import/export agreement with Canada and a special Presidential permit to authorize project implementation. Previous Studies Numerous studies relating to the proposed interconnection of Southeast Alaska's electric load centers and hydroelectric generation projects have been performed in recent years. Stud- ies pertaining directly to the proposed project include the 1982 report, Southeast Alaska Intertie DC Transmission System, for the Alaska Power Administration (APAd) by Teshmont Consultant Inc.; the 1980 report, Snettisham-Ketchikan Transmission System, for the APAd by Harstad Associates; and the U.S. Forest Ser- vice's Tongass Land Management Plan. Other previous studies performed for the Alaska Power Authority, which bear on the Southeast Intertie, concern the development of specific hydro- electric and transmission intertie projects such as Tyee Lake, Swan Lake, West Creek, Lake Dorothy, and the Tyee-Kake Intertie. Resource management plans such as the U.S. Forest Service's Draft Environmental Impact Statement on the Quartz Hill Molybdenum Project Mine Development and the USFS Chatham and Stikine Areas 1986-90 management plan EIS report, various com- munity coastal management plans, and the Alaska Department of Transportation and Public Facilities' regional transportation plans for Southeast Alaska were also consulted in the course of this effort. Concurrent with the study described herein, R.W. Beck Asso- ciates prepared the reports "Juneau Area Electric Load Forecast" (April 1987) and "Southeast Alaska Electric Load Forecast" (April 1987) for the Alaska Power Authority. These two studies provide the electric load demand forecasts upon which the preliminary transmission interconnection designs and economic analyses presented herein are based. A bibliography of the consulted reports is included at the end of this volume. Acknowledgements We acknowledge and appreciate the valuable assistance and advice offered by the staff personnel of the following: 1-11 Alaska Alaska Alaska Alaska Alaska Alaska Alaska Alaska Alaska Alaska Cape CLEY, city City City City City: Gity. City Fo of an of of an of of of Federal Glacier Department of Environmental Conservation Department of Fish and Game Department of Natural Resources Department of Transportation and Public Facilities Division of Governmental Coordination Electric Light and Power Company Power Administration Power Authority Power and Telephone Company State Historic Preservation Officer x Corporation Haines d Borough of Juneau Ketchikan Petersburg d Borough of Sitka Skagway Thorne Bay Wrangell Aviation Administration Highway Electric Association, Inc. Greens Creek Mining Haines Light and Power Ketchikan Gateway Borough Ketchkian Public Utilities Metlakatla Power and Light 1-12 National Marine Fisheries Service National Park Service Sealaska Corporation South Coast, Inc. Southeast Conference Tlingit and Haida Regional Electric Authority U.S. Borax U.S. Coast Guard U.S. Environment Protection Agency U.S. Fish and Wildlife Service U.S. Forest Service l=s Chapter 2 POWER SYSTEM PLANNING Introduction Interconnection of the load centers and generation sources in Southeast Alaska will ultimately require the establishment of a governing body, or operating council of a form similar to those common in the contiguous 48 states. The operating council would consist of member load center and generation source utili- ties and would establish operating rules, set rates, operate and maintain system facilities, dispatch loads and establish system expansion planning and reliability criteria. No such operating council currently exists in Southeast Alaska. In the absence of an existing operating council and estab- lished system expansion planning and reliability criteria, it was necessary to formulate criteria for use in this study to facilitate power system studies of the proposed transmission intertie configurations. The power system studies were per- formed to determine the appropriate capacity required for each intertie segment, to estimate line losses, and to evaluate the electric characteristics of the various Intertie configurations considered. The following paragraphs describe the planning and relia- bility criteria established, the power studies performed and present the results of the system studies. System Planning Criteria In consultation with the Alaska Power Authority the follow- ing system planning criteria were adopted for the power system studies effort: its Voltage at transmission substations, under normal system conditions, will be maintained with a range of plus/minus 5% of the nominal voltage level. 2 Under single contingency line outage conditions, bus voltage will be allowed to go to 90% of the nominal voltage level. 36 The power factor at the load center power delivery locations will be maintained at 95% or higher. 4. Local generation will be operated as necessary to provide voltage regulation and system inertia. The studies were performed assuming maximum output from system hydro generation plants, with supplemental generation from local hydro plants and, lastly, thermal generation sources. System Reliability Criteria The following system reliability criteria were developed in consultation with the Power Authority: 1. Sufficient generating capacity will be provided, as nearly as practicable, to provide a fixed capacity including reserve that is greater than the forecast maximum demand of the Intertie System. The Intertie System planning will be designed to assure that the system will not experience cascading breakup and collapse initiated by the occurrence of contingencies such as: a. Loss of all generating capacity at any generating station. b. Loss of any two generating units. Cs Outage of any two circuits or generating units during scheduled maintenance on any other trans- mission line or generating unit. d. Outage of any single or double circuit transmis- sion line, generating unit, transformer, or bus. e. Simultaneous outage of overhead transmission lines parallel to each other for a substantial distance having a spacing between circuits of less than the height of the structures. f. Any fault, cleared by normal operation or backup relays. g. Loss of any large load or concentrated load area. Power System Studies Studies of the various Intertie System configurations were performed on a personal computer using a commercially available software program from Electrocon International, Inc. The program creates a mathematical model of the interconnected generation and transmission system, and computes real and 2-2 reactive power flows as well as bus voltage levels. With this analytical tool it is possible to determine how a proposed system would perform in steady state under various operating scenarios. For this study the load flow program was used to model the proposed transmission line additions, transformers and genera- tion dispatch conditions. Using the load flow program it is possible to establish power flow conditions on each proposed transmission circuit. The program is designed primarily for modeling alternating current transmission systems. To represent the direct current lines, a two step process was used. First an AC transmission line with minimum resistance and reactance was assumed in the location of the DC line, and the case was solved. A second case was then formulated without the proposed DC con- nection, but in place of its terminals a load and a generator were modeled. The magnitude of the load and generator were equal to the equivalent DC power flow as calculated in the first step. Although not an exact model, this technique allows for a planning level model that represents how a DC line would func- tion as part of an interconnected regional transmission system. In the event that a DC line were found to be economically feasible, it would then be necessary to make detailed engineer- ing design studies with more precise and exact DC. transmission line models. The basic input requirements of the load flow program for planning level studies are the following: lie Transmission line and transformer resistance, reactance and shunt charging values. 2. Generator real power output. fe Generator reactive power output limits. 4. Transformer tap settings. 5. Shunt reactor ratings. 6. Real and reactive bus load values. 7. Range of acceptable bus voltage limits. 8. Designation of one generator as the swing machine for the system. 2-3 ~~ The results of a load flow calculation are real and reac- tive power flows through transmission lines and transformers together with associated bus voltage levels. The program also computes real power losses for the alternating current system. The power system studies were performed using the year 2006 high load forecast shown in Table 2-1. The forecast is the preliminary forecast furnished by the Power Authority in October, 1986. Comparison with Tables 1-2 through 1-4 will reveal that the preliminary forecast is generally higher than the Power Authority's final forecast for the load centers. Nevertheless it was deemed prudent to base the formulation of the Intertie System on the preliminary, high, year 2006 forecast thereby assuring sufficient capacity in the system for later years. Power System Alternatives Power flow studies were prepared for a Basic Intertie Plan and several variations as described in the following paragraphs. The names of the system configurations that were studied are: Plan I - Basic Intertie Plan (Figure 2-1) Plan II - Overland North of Juneau (Figure 2-2) Plan III - AC to Sitka, West Route (Figure 2-3) Plan IV - Radial to Angoon (Figure 2-4) Plan V - Cleveland Peninsula (Figure 2-5) Plan I - Basic Intertie Plan Of the systems considered, this system configuration has the most submarine cable and the least overland transmission line. The plan was prepared according to the requirements of the original contract scope of services and includes necessary transmission lines and substations to interconnect ten load centers, the Quartz Hill mine, and five major hydroelectric generating stations in Southeast Alaska; see Figure 2-1. Also included are two connections with Canadian electric power systems. From Skagway, a transmission connection to the North Canadian Power Commission System at Whitehorse is included and, at the southern end of the study area, a transmission line is extended from Swan Lake to Quartz Hill mine and then to the B.C. Hydro system at the Kitsault Substation. 2-4 Table 2-1 LOAD FORECAST USED FOR POWER SYSTEM STUDIES Year 2006 Peak Load Demand Center kw Skagway 1,740 Haines 2,880 Juneau (Auk Bay & Thane) 97,600 Kake 1,340 Sitka 32,900 Petersburg 8,340 Wrangell 4,840 Ketchikan 31,000 Prince of Wales Islandal/ 9,700 Metlakatla 5,670 Quartz Hill 96,000 Green's Creek 5,000 Hoonah 1,337 Angoon 853 Tenakee Springs 380 i/ Includes loads at: Craig, Hydaburg, Klawock, and Thorne Bay. FIGURE 2-1 WHITEHORSE SKAGWAY HAINES HOONAH e GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS @ ancoon 100KV DC PETERSBURG PRINCE LEGEND: OF WALES @ - Loan centers © - GENERATION SOURCES KETCHIKAN eee - EXISTING T/LINE PROPOSED T/LINE QUARTZ METLAKATLA T/KITSAULT 100KV DC (BIPOLAR) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY PLAN I - BASIC INT HARZA ENGINEERING COMPANY ocvoss= 1987 ERTIE PLAN The Basic Intertie Plan utilizes the three major existing transmission lines in Southeast Alaska. Direct current power transmission is used for submarine cable runs that exceed 25 miles in length. Plan II - Overland North of Juneau Instead of the submarine cable interconnection between Skagway, Haines and Juneau used in Plan I, Plan II would use overland transmission along the east side of Lynn Canal. See Figure 2-2. A transmission line would be constructed from Skagway to the Auke Bay substation north of Juneau. The inter- connection with Haines would be via a submarine cable from a substation located on the east side of Lynn Canal, opposite Haines. This configuration was proposed as an alternative to the Snettisham-Kake DC cable in Plan I. As shown on Figure 2-3 a 138 kV AC overhead transmission line, with several relatively short submarine cable crossings, would be constructed from Thane Substation south of Juneau, to the west across Douglas Island, Admiralty Island, Chichagof Island, and south to Baranof Island. The line would deliver power to load centers at Greens Creek Mine, Hoonah, Tenakee Springs and Sitka. A radial line to Angoon could also be provided from the Tenakee Springs-Sitka segment. This plan is technically difficult because it requires transmission of modest amounts of power over long distances at the selected voltage, 138 kV. Load flow studies show that there will be voltage regulation difficulties unless appropriate measures are taken. Consequently, this plan includes shunt reactors and a static var compensator at the termination on Baranof Island. The static var compensator would also be required to provide reactive power to the DC converter-inverter station for the long cable connection to the southern portion of the Intertie System via Kake. The selection of 138 kV transmission voltage is dictated by the total overall distance from Juneau to Sitka. As a result, the delivery of power at Hoonah, Tenakee Springs and Angoon would result in lightly loaded transformers. Studies of this connection at 69 kV indicate that voltage regulation problems would make 69 kV transmission impractical. FIGURE 2-2 HooNAH @ GREENS CREEK e SNETTISHAM- CRATER LAKE TENAKEE SPRINGS PETERSBURG PRINCE LEGEND: OF WALES @ - Loan centers O GENERATION SOURCES — EXISTING T/LINE PROPOSED T/LINE QUARTZ METLAKATLA KITSAULT 100KV DC (BIPOLAR) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY PLAN II - OVERLAND NORTH OF JUNEAU + OCTOBER 1987 FIGURE 2-3 HOONAH GREENS CREEK D SNETTISHAM- CRATER LAKE ~ TENAKEE ANGOON 100KV DC eo PETERSBURG PRINCE LEGEND: OF WALES @ - Loo centers - EXISTING T/LINE © - GENERATION SOURCES — - PROPOSED T/LINE QUARTZ METLAKATLA 100KV DC (BIPOLAR) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY PLAN Ill - AC TO SITKA, WEST ROUTE HARZA ENGINEERING COMPANY ; OCTOBER 1967 Plan IV - Radial to Angoon This plan was proposed in response to the Public and Agency request to include the load centers of Hoonah, Tenakee Springs and Angoon. It is similar to the preceding case except that there is no connection to the Sitka system. Consequently, line loadings are light, but extensive var compensation is not required with this plan. Voltage regulation would be from transformer tap settings and local generation. See Figure 2-4. Plan V - Cleveland Peninsula This variation was developed in response to suggestions that Ketchikan could be provided with increased reliability if it were connected to Tyee generation by a transmission line that waS on a separate right-of-way from the Swan Lake line. As shown on Figure 2-5, Plan V has the additional advantage that it allows a connection to Prince of Wales Island with an alternat- ing current cable across Clarence Strait instead of the direct current cable from Ketchikan shown in Plan I. The plan requires construction of a 138/69 kV step-down substation in an isolated area of the Cleveland Peninsula. Other Radial Lines Other radial connections considered include lines from Ketchikan to Metlakatla and from Ketchikan to the proposed Prince of Wales Island Intra-island transmission system, Previous studies have indicated that the Prince of Wales system should be a 69 kV AC overhead system serving Thorne Bay, Hydaburg, and the Klawock/Craig load center. An interconnection between Klawock and Craig at 12.5 kV is planned to be imple- mented by the Power Authority in the near future. Three alternative methods of interconnecting Ketchikan and Metlakatla were considered. These are as follows: 1. A 69 kV interconnection from Ketchikan Public Utili- ties' (KPU) Bailey Substation. The intertie route includes 7.5 miles of new 69 kV construction through Ketchikan and Saxman, a one mile long cable crossing of Revillagigedo Channel from Mountain Point to Race Point and 14.0 miles of 69 kV line with an intercon- nection to Metlakatla Power and Light's (MP&L) planned Chester Lake Project. OG A 69 kV interconnection from KPU's 34.5 kV Mountain Point Substation. The connection would require installation of a 34.5 kV/69 kV step-up substation at 2-6 FIGURE 2-4 t WHITEHORSE ™ L138 KY 5 . C4 4 N4 75KV DC ~20%4 HAINES ve™, SKAGWAY SOON GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON 100 KV DC PETERSBURG PRINCE LEGEND: OF WALES ISLAND @ - Lodo centers © - GENERATION SOURCES KETCHIKA| meee - EXISTING T/LINE PROPOSED T/LINE QUARTZ METLAKATLA 100KV DC (BIPOLAR) KITSAUET ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY PLAN IV - LIARZA enanesans company ccroses 127 RADIAL TO ANGOON HOONAH e GREENS CREEK TENAKEE SPRINGS @ ancoon 100KV DC _ PRINCE LEGEND: OF WALES @ O LOAD CENTERS GENERATION SOURCES EXISTING T/LINE PROPOSED T/LINE WHARZA ensineerins company OCTOSE= 19! FIGURE 2-5 SNETTISHAM- CRATER LAKE PETERSBURG KETCHIKAN QUARTZ METLAKATLA Z, 100KV DC (BIPOLAR) ar eee ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY PLAN V - CLEVELAND PENINSULA er Mountain Point and the submarine cable crossing and 14.0 mile overhead line previously described. 3. A 34.5 kv interconnection from KPU's Mountain Point substation. The cable crossing of Revillagigedo Chan- nel and overhead line on Annette Island would be as described above, but at a voltage of 34.5 kv. The 69 kV connection from Bailey Substation is preferred because it does not involve the KPU distribution system. That is, power flow variations at the MP&L load center would not enter the KPU system. The other two alternatives would require that power to MP&L pass-through the KPU distribution system. This would result in increased losses in the KPU system, and disturbances originating in the MP&L system would cause undesir- able voltage fluctuations in the KPU system. AC Versus DC Transmission There is a significant difference between the maximum practical power transmission distance for an overhead line and an electric power cable when both are at the same voltage. As explained in the literature,1/ the practical length for high voltage alternating current cables is on the order of twenty five miles. Direct current cables, however, do not have the characteristic of reactance and capacitance that alternating current cables have. Therefore they do not have the distance limitation that alternating current cables have. Direct current cables do have voltage drop and loss consid- erations, but they are determined by series resistance. Voltage drop can be made to fall within acceptable limits by providing a cable with a sufficiently large conductor. Voltage drop and losses are reduced as the resistance is reduced. When this limitation for high voltage AC cables is applied to the formulation of a transmission system for Southeast Alaska the following transmission segments are found to require sub- marine cables that are longer than twenty five miles. Skagway - Haines - Auke Bay Snettisham - Kake Kake - Blue Lake (Sitka) In these cases it will be necessary to use direct current cables as the transmission method. A/ Kimbark, E.W. 1971. Direct Current Transmission, Wiley International. Volume 1. 25 pp. 2-7 Application of HVDC TO S.E. Intertie System High Voltage Direct Current (HVDC) transmission line tech- nology is being successfully applied in a large number of modern power systems. HVDC finds application for several technical- economic reasons. The applications are summarized as: 1. Long Distance Power Transmission 26 Controllability Se Submarine Cable Systems 4. Interface (between two systems of different frequency) Se Asynchronous Interconnection (System Stability) Plan I, proposed for the S.E. Intertie Study, included five HVDC installations. Each of these was proposed because it met one or more of the five application requirements. As noted above the Skagway/Haines/Juneau, Snettisham/Kake and Kake/Sitka installations were formed as HVDC installations because the proposed routes included submarine cables with lengths exceeding 25 miles. In addition, HVDC transmission was proposed for the Quartz Hill/Kitsault and Ketchikan/Prince of Wales Island lines to resolve system stability problems for power flow control considerations. In DC transmission, ground (sea) return can be used as one conductor. This means that each separately insulated transmission conductor together with the ground-return path forms a separate electric circuit. Based on this fundamental, the following three basic circuit arrangements can be considered. i Monopolar Arrangement. One transmission conductor (pole) is installed and ground (sea) return is used permanently. Monopolar transmission is used in systems of comparatively low power rating, and mainly with cable transmission. As shown in the following list the monopolar sea return arrangement has been selected for use in both European and North American applications. 2-8 LIST OF MONOPOLAR HVDC INSTALLATIONS Project I Location Gotvand-Sweden Skagerak, Norway- Denmark Kanti-Skan, Denmark-Sweden Sardinia, Italy Vancouver Island, B.C. Canada Rauma, Finland- Forsmark, Sweden 2. Bipolar nstallation Date 1954 1970 1976 1965 1967 1968 Pole #1 1969 Pole #2 1976 Pole #3 Under Constr. 20 30 250 250 200 78 312 500 420 Capacity MW MW MW MW MW MW MW MW Voltage 100 150 250 250 200 130 260 280 360 KV KV KV KV KV KV kV KV Comments No overhead transmission: 60 miles (96 km) underwater cable. Initially operated mono- polar. Up- bipolar opera- tion in 1977. 54 miles (88 km) overhead transmission and 54 miles (87 km) of underwater cable. 187 miles (301 km) overhead transmission and 73 miles (118 km) of underwater cable. 26 miles (41 km) overhead transmission and 20 miles (32 km) under- water cable. 112 miles (180 km). Route Vv survey under- way in 1986.=6 : In bipolar transmission ground (sea) return is not necessary, but is provided to increase transmission availability in case of failure of one pole. 2-9 Se Homopolar: This is a version of bipolar except that both poles transmit current in the same direction, and earth (sea) is used as the return path. Use of sea return path with a monopolar DC system may not be feasible in urban areas because of probability of interfer- ence with existing underground metallic structures and facili- ties. However, in the case of Southeast Alaska the conditions are similar to those where monopolar systems are in operation. Selection of the DC arrangement for the various Southeast intertie DC segments is based on striking a balance between reliability requirements and initial capital cost. The Intertie load centers will, for the most part, be interconnected to the grid by more than one transmission link and will also, under the assumptions made herein, be required to maintain sufficient local hydro and/or standby diesel capacity to meet local power and energy requirements in case of a transmission line outage. This level of reliability is deemed sufficient to justify selec- tion of the monopolar arrangement for all but the Quartz Hill/ Kitsault interconnection. Because the reliability of the mine's power supply will be of paramount concern, a bipolar DC trans- mission arrangement was selected for this interconnection. The monopolar systems can be upgraded to bipolar by the addition of a parallel conductor, as was done for the Vancouver Island interconnection and on the Shagrek Project in Norway/Denmark. Of the three manufacturers contacted for engineering input regarding the application of DC transmission for the Intertie, two, ASEA and Siemens, responded regarding the use of monopolar systems, as follows: Siemens Letter Dated May 1, 1987: "Monopolar DC with sea return is practicable. Potential problems such as environ- mental concerns and interference with submarine navigation systems, need to considered. Typically, because of such concerns in conjunction with redundancy considerations, sea return is used as back-up mode only". ASEA Letter Dated March 4, 1987: "Sea return has been used projects..... In some parts of the United States there may be licensing (permitting) restrictions affecting continuous sea return for a monopolar DC system. This needs to be investi- gated". 2-10 HVDC Costs and Developments The present commercial applications of high voltage direct current are in the higher voltage range and at high capacity levels. The minimum ratings in use to date are on the order of 100 MVA and about 200 kv. An electric power system has been developed for the S.E. Intertie that is based on the requirements of the interconnected system for the year 2006. At this load level the high voltage direct current power requirements range up to 50 MW. For the purpose of the study, cost estimates for HVDC equipment were obtained from manufacturers. This cost informa- tion was given with the caveat that the design and manufacture of such equipment, using present technology, would be non- standard. That is, it would be a unique order, and the costs would reflect extra engineering and special modifications needed in the manufacturing processes. There are an increasing number of potential applications of HVDC at power levels less than 100 MW, and voltages less than 200 kV. Manufacturers indicated an awareness of this, and it appears that they may attempt to address the needs of this market in the near future. In addition to the increasing number of smaller size HVDC applications, there is also the possible pe ¥ 5.9 ent of new technology from one of the research agencies.2 Two such agencies and their areas of interest are: 1. Manitoba Hydro Research - Forced Commutation. 2 Electric Power Research Institute - Gate Turn-off Thyristors (GTO). Future studies of a S.E. Intertie should reevaluate the status of HVDC manufacturing capability and costs. 2/ "Comparison of Costs and Benefits for DC and AC Transmis- sion", Report ORNL - 6204 prepared by Oak Ridge National Laboratory, Feb. 1987. 3/ "High Voltage Direct Current Research Program" W. Long and P.A. Gnadt, report prepared for Oak Ridge National Labora- tory, Sept. 1986. 2-11 Study Results Figures 2-6 through 2-10 are single line diagrams of the transmission system alignments that were formulated and analyzed with the load flow program. These systems, although acceptable from the engineering point of view, were used as the basis for the economic screening and analysis. Based on economic consid- erations these systems subsequently were revised and simpli- fied. As shown on the figures, the Intertie System is planned to be predominantly a 138 kV AC system with 100 kV DC links between Snettisham and Kake, and/or Sitka and Kake, and with 69 kV radial transmission lines to serve remote load centers as warranted. Deviations from this include 34.5 kV service to Haines and Green's Creek Mine in some plans, 75 kV DC service to Prince of Wales Island, and the bipolar 100 kV DC line between Quartz Hill and B.C. Hydro at Kitsault, B.C. Also, in all plans considered, the existing 115 kV AC Swan Lake-Ketchikan transmis- sion line would remain as is. These deviations from the stand- ard represent the least cost technically acceptable alternatives for use in the economic analyses presented herein. The merits of upgrading the lower voltage lines to provide standard AC and DC voltages throughout the S.E. Intertie system should be evalu- ated during the detailed transmission line design. Energy Losses The Southeast Intertie system will experience energy losses as part of normal operation of the bulk power transmission system. These losses would be the result of power flow through transmission lines and cables, and through DC/AC converter and inverter stations. Alternating current cables also have the characteristic of dielectric losses in the insulating medium. The analysis of losses performed for this study does not include power conversion losses. It is assumed for this analy- sis that power conversion losses would be roughly equivalent in all plans. Energy losses for the Intertie Expansion Plans, described in Chaper 7, were calculated using information based on power system operation and power flow calculations for the proposed systems. Table 7-12 is a tabulation of losses for each of the expansion plans. The information in the table gives the esti- mated energy losses for each category of loss, and the estimated total annual losses. The values are based on the system with loads at the most likely load demand forecast level for year 2006. (Refer to Chapter 7 for the results of these studies). 2-12 FIGURE 2-6 PROPOSED SOUTH CANADA EAST ALASKA U.S.A INTERTIE SYSTEM eee YEAR 2006 SKAGWAY PLAN 1 AUKE BAY 138KV JUNEAU AREA CRATER LAKE SNETTISHAM 138KV SITKA 69KV 69KV GREEN LAKE 1 \38KV rout PETERSBURG LEGEND kawe rank © SYSTEM SENERATION < t, ON WRANGELL v LOAD BUS % (36KV Sw. YO. CABL TERMINATION —PS cable 8 ni28KV * A.C./D.C CONVERTER 3 STATION SWANS z LAKE e VsAv AUTO TRANSFORMER | Be + D.C. GROUND ELECTRODE 138KV QUARTZ HILL MINE KETCHIKAN KLAWOCK SKV THORNE BAY 69KV CRAIG 12.5KV METLAKATLA HYDABURS HIARZA ENGINEERING COMPANY - OCTOBER 1887 NCPC t WHITEHORSE 38KV HAINE 138KV CANADA U.S.A Jf 7 SKAGWAY > = a 138kV AUKE BAY | =... FIGURE 2-7 OVERLAND NORTH OF JUNEAU PROPOSED SOUTH EAST ALASKA INTERTIE SYSTEM YEAR 2006 PLAN Il LYNN CANAL (EAST) JUNEAU f AREA 4, CRATER SNETTISHAM LAKE \38KV t BLUE XJ SITKA 69KV CARE 69k z = © SJ 1OOKV 8 ! GREEN A | LAKE Ld i LEGEND (38KV PETERSBURG OWEN isaxy oa KAKE ‘D) SYSTEM GENERATION Ss, s. WRANGELL y LOAD BUS % i38KV \ —P4— CABLE 2 TERMINATION Sw. YO (38KV & A.C./0.C CONVERTER 138KV 3 STATION SWAN a LAKE 4 ob. AUTO TRANSFORMER ©) SKY TYEE 138K + b.c. GROUND ELECTRODE oe ey 138K’ RT aterm OL RS KLAWOCK THORNE BAY SKY Lb Z 69KV 69KV a x L m4 VS x > x % 7SKV mon CRAIG 6gkv CANADA 12.5KV eaKxy SZ | sanv Xd KITSAULT as METLAKATLA SOOKV aYDABURS Bc HYCRO HARZA encinceRING COMPANY - OCTOBES 1887 a FIGURE 2-8 NCPC AC.TO SITKA,WEST ROUTE S NHITEHORSE PROPOSED SOUTH aay | ANADA EAST ALASKA U.S.A INTERTIE SYSTEM Dee YEAR 2006 PLAN i HAINES 5 AUKE GAY | 138 KV j 138KV 5 JUNEAU AREA HOONAH 138k 138KV THANE 2 8KV REMOTE fe, 13 ! TENAKEE ty, SPRINGS ee © @ state ANGOON ~ LAKE sexv aaKY i3gKv ae SITKA Sov Cae 69Ky | SZ i SJ 1OOKV \ Oo GREEN CAKE “a \38KV LEGEND PETERSBURG NE I38KV | P= KAKE \ o SYSTEM SENERATION < | +, Ss. WRANGELL \y -LOAD Bus % (38KV —P4— CABLE & TERMINATION swe) (38KV s A.C./D.C CONVERTER 138KV os STATION SWAN 3 | LAKE S we AUTO TRANSFORMER (~~) WSKV TYEE 138KV + b,c. GROUND ELecTRovE we oe 138KV BUARTZ KETCHIKAN Fr MINE: KLAWOCK THORNE BAY lISKY 69KVv 7 69KV Paes eee bX —+ | . x 75kV wiaan CRAIG 63k CANADA 12.5KV . i eoKV Baeany METLAKATLA N HYDABURS HARZA encineeRING COMPANY - OCTOSE® 1887 FIGURE 2-9 NCPC RADIAL TO ANGOON WHITEHORSE PROPOSED SOUTH 138KV CANADA EAST ALASKA | USA INTERTIE SYSTEM TS SKAGWAY YEAR 2006 PLAN iv + T5KV . HAINES 75KV + 5 = AUKE BAY i GREEN \ CK. MINE coky ! 69KV 69KV 5, JUNEAU 7 AREA 63KV | HOONAH 69 KV 138KV THANE | &, 2 TENAKEE 69KV ay eee SNETTISHAM (~) ceetee ANGOON 69KV fake BLUE nA SITKA 69k CAKE 5 T > oy Ld) bh 3 Ss 100 Kv 2 GREEN “J LAKE < (38KV LEGENS PETERSBURG — KAKE 138KV © SYSTEM SENERATION S$ . Sy. WRANGELL Y =OAC BUS % 138KV —PH— CABLE & TERMINATION sw. 70 mi 3OKY . XE A.C/D.6 CONVERTER 138«V % “STATION SWAN 3 ’ LAKE & U4 AUTO TRANSFORMER ~) i liSkV TYEE 138K + dc. GROUND ELECTRODE aw aS KETCHIKAN '28KV QUARTZ KLAWOCK THORNE BAY SKY BEL MINE: 69Kv 69aKv PA i t vey USA. CRAIG Sok’ CANADA I2.2KV 69KV E SAULT wee METLAKATLA 500K EO HYDABURS BC. HYSRO WHARZA eNcineeRING COMPANY OCTOBER 1887 NCPC CLEVELAND PENINSULA t WHITEHORSE PROPOSED SOUTH \38KV CANADA EAST ALASKA i U.S.A INTERTIE SYSTEM YEAR 2006 SKAGWAY £ rae PLAN Y 75KV HAINES x 75kv 1 = RA AUKE BAY XJ GREEN CK. MINE eR | 34.5KV 69KV \ JUNEAU AREA a 69KV 7 wy a 138KV THANE ; ¢ ar, SNETTISHAM ~ © ceeen (38KV 7 BLUE Xd SITKA 69KV Cane eaxv g = O es 100 Kv S GREEN Bd CAKE 138KV LEGEND PETERSBURG LEE! RAKE 138K © SYSTEM GENERATION SENINSULA a +, 138k 3. WRANGELL \ LOAC BUS % 136KV 69KV- « —PS— CABLE & TERMINATION Sw. YO. \38KV % AK Ac ioc converter = STATION SWAN OY z LAKE Ss ube AUTO TRANSFORMER ~) | USKV TYEE 138KV Ae we L b,c. GROUND ELECTRODE Issey oS y RTZ KETCHIKAN 'SBKY. pontiac KLAWOCK THORNE | BAY IS KY 69KV 6oKv 69KV USA. CRAIG CANADA 12.5KV 69Kv US) errsauer SoKy METLAKATLA sooKy HYDABURS B.C. HYDRO HARZA ENGINEERING COMPANY OCTOSER 1987 FIGURE 2-10 The energy loss values are determined from peak megawatt loss, and are converted to energy according to load and loss factors. The loss factor is taken at the nominal value of: 0.7 (load factor**2) + 0.3 (load factor). In more detailed analyses of the individual transmission segments, studies snould be performed of the load diversity of the various consumer cate- gories in the load centers to be served, to accurately determine the appropriate load and loss factors. (See referencel/ for a discussion of load and loss factor). The calculation of estimated losses for the AC/DC inverter - converter stations is based on a demand loss of 1% of station capacity. The value of 1% is taken from manufacturer's litera- ture and engineering papers. The amount of actual loss at each station will vary according to the design and amount of filters required at each station. Direct current cable loss is calculated as the current squared resistance product, and converted to energy according to system load and loss factors. The alternating current system loss is taken from load flow calculations as the megawatt loss at peak load, and converted to energy. Alternating current cable has losses that are the result of current leaking through the cable insulating dielectric material. Cable dielectric losses are directly related to the type of insulating material used in the cable design. In this study the dielectric losses have been calculated for the South- east Intertie system for cables with Ethylene Propylene Rubber (EPR) insulation. (See Chapter 3 for a discussion of cable insulation and dielectric loss). Cable dielectric losses are present whenever the cable is energized, and are independent of power flow through the cable. This means that cable dielectric losses are encountered each hour that the cable is in service. For this analysis cable dielectric losses are based on 100% load and loss factors. If system economics allow losses to be allocated to hydro energy and the value of water is small, then dielectric losses May not be of consequence. However, losses of this magnitude have a significant economic consequence on a system with large amounts of thermal energy conversion. It should be noted that there is also incremental capacity required to meet the loss demand. A future formulation of a ; more definite Southeast Intertie system should include consid- eration of the cost of this loss. 1/ ‘EPRI, Technical Assessment Guide, P-2410-SR, May 1982, Palo Alto, CA, pp. 6-6. 2=1\3 Chapter 3 SUBMARINE CABLE DESIGN CONSIDERATIONS AND COST ESTIMATES The studies described in Chapter 2 established the required capacities of the various transmission line segments based on single contingency outage criteria. In this chapter, the studies which resulted in the selection of the recommended sub- marine cable crossings are described. Further, the estimated costs of the various cable crossings are given. Submarine Cable Surveys Based on studies of USGS 1:63360 scale quad maps and NOAA navigation charts, potential submarine cable routes for ten of the original 11 stipulated transmission intertie segments were selected within the macro-corridor for each segment. Table 3-1 lists the routes selected for survey and Figure 3-1 gives their locations. As indicated on both the table and the figure, the survey of two additional potential cable crossings for trans- mission interconnections of Ketchikan and Metlakatla, and Quartz Hill and Prince Rupert, B.C. were also considered. Surveys of the selected crossing locations were performed by Harding Lawson Associates, during the period October 12 through October 31, 1986. In addition to Harding Lawson and its subcontractors, the survey crew included a representative of the Alaska Power Authority and also a submarine cable installation expert furnished by Pirelli Cable Corporation. During the course of the survey, it was decided, with the approval of the Power Authority, not to perform surveys of the following routes due to budgetary constraints and the existence of previous surveys by others: Transmission Line Segment No. Crossing From To 4 Chatham Strait Greens Creek Hoonah 8.5/8.6 North Behm Canal Tyee Lake Swan Lake 11 Portland Canal Quartz Hill Kitsault, B.C. 13 Behm Canal/Revillagigedo Channel/Chatham Sound Quartz Hill Pee Rupert, On completion of the surveys Harding Lawson Associates analyzed the data collected and prepared draft and final survey 3-1 Table 3-1 SUBMARINE CABLE ROUTES SELECTED FOR SURVEY sion Line Segment Intertie megment Transmis No .— Crossing From 2.1 Lynn Canal Skagway Ae Lynn Canal Haines 3 Stephans Passage Juneau 4 Chatham Strait2/ Green's Creek 562/504 Port Snettisham/Stephans Passage/Fredrick Sound Snettisham 6.1 Wrangell Narrows Petersburg 6.5 Duncan Canal Petersburg wet Fredrick Sound/Chatham Strait Kake 8.5/8.6 North Behm Canal2/ Tyee Lake 9.1 Tongass Narrows/Clarence Strait Ketchikan 10.6 Behm Canal Swan Lake 11 Portland Canal2/ Quartz Hill 12 Revillagigedo Channel Ketchikan 13 Behm Canal/Revillagigedo Channel/Chatham Sound2/ Quartz Hill if These numerical designations were subsequently revised. 2/ The indicated surveys were not performed due to budgetary constraints and the existence of previous surveys. To Haines Juneau Green's Creek Hoonah Kake Kake Kake Sitka Swan Lake Prince of Wales Is. Quartz Hill Kitsault, B.C. Metlakatla Prince Rupert, B.C. FIGURE 3-1 r37¢ 136° 135° se 333° 1320 131° 1308 T T T T T | ° Whitenorse | ae LEGEND | “ | e Load Center ° Generation Source | —— Proposed Transmission Line GULF OF ALASKA Note | Base map taken from USDA | Forest Service General Technical Report PNW - 66,1978 ° 3 30) 45 ‘cale Mies C ZA j Se | ZA ca | To Prince Rupert, B.C. | | | e& Map Area | i | +322 1370 136° 138° 1346 133° 332° i310 1. Refer to Table 3-1. 2. Routes 4, 8.5/8.6, 11 and 13 ALASKA POWER AUTHORITY | eee Oe CRO CUS Lae SOUTHEAST INTERTIE STUDY | SURVEYED SUBMARINE CABLE ROUTES | | | \ | | WARZA ENGiNceRING COMPANY - OCTOBER 1987 reports including plan and profiles of the surveyed routes. The final survey report is attached hereto as Appendix A. The Pirelli representative aboard the survey vessel also prepared an account of the conducted surveys. This report is given in Appendix B. Selection of Final Cable Routes The selection of acceptable final cable routes is a pre- requisite to selection of a preferred cable design. A surveyed route that indicates rapid changes in slope, large rock outcrops and/or boulders at the bases of steep approaches to landings should be avoided. Therefore, on some of the surveyed cable crossings routes, additional detailed surveys should be imple- mented using divers and side scan sonar to determine acceptable cable routes. A summary of the cable routes surveyed is listed in Table 3-2 with comments regarding route suitability and/or the need for additional surveys. As shown on the table, several of the surveys have indi- cated problem areas along the selected routes. The laying of submarine cable along rapidly changing slopes or with landings at steep and rocky points is not recommended. Under such condi- tions the cable might be layed with free spans and thus sub- jected to movements due to tidal action causing wear of the armor wires and fatigue of a lead sheath. To avoid this, addi- tional surveys of some routes to facilitate selection of route alternatives that have a relatively smooth bottom and approaches to landing points are recommended. Table 3-2 SUMMARY OF SUBMARINE CABLE SURVEYS Plate No.1/ cable Crossing Te 2.1 Skagway to Haines 2.2 Haines to Bridget Cove 2. 3. South Douglas Island to Young Bay, Admiralty Island 4. 5.2/5.4 Port Snettisham to Kupreanof Island 5. 6.1 Wrangell Narrows, Mitkof to Lindenburg Peninsula 6. 6.5 Duncan Canal 7. 7.1 Kake to Warm Springs Bay, Baranof Island 7.4 126 1.5 1.7 56.3) Naut. Miles 4.0 68 0.8 1.1 30.0 Comments Steep approach and rapid changes in slope at Haines side. Additional survey required for alterna- tive route. Feasible route. Approach to Kupreanof steep and rocky. Additional survey data required for alternative route. Feasible route. Steep landing site on east shore. Feasi- ble route. Additional survey data required. Pt. White landing, rocky with offshore ledges. Crossing of Frederick Sound acceptable. Pt. Gardner and Yasha Island rapid changes in slope. Additional survey required for alternate route. 1/ Refer to Harding Lawson Associates report, Appendix A. 3=3) Plate No .1/ 8. 10. 11. 12. IS Table 3-2 (Cont'd) SUMMARY OF SUBMARINF CABLE SURVEYS Cable Crossing 8.5 Bell Island- Beaver Creek 8.6 Point Lees- Claude Point North Behm Canal 9.1 Ketchikan to Grindall Pt., Kasaan Peninsula Prince of Wales Island 10.6 Pt. Trollop to Revillagigedo Island 11. Portland Canal 12.2 Mountain Point, Revillagigedo Island to Race Point, Annette Island 1.1 26 12.5 2.2 ley) Naut. Miles 0.6 0.6 14.0 6.7 1.2 0.7 Comments Feasible route. Feasible route. Rapid changes in approach to cove north of Mud Bay. Additional survey data needed for alter- native route. Approach to Pt. Trollup steep. Additional survey data required. Approach to Columbia Point very steep. Additional survey data required. Feasible route. Additional survey data required. Refer to Harding Lawson Associates report, Appendix A. 3-4 Submarine Cable Designs Based on the bathymetric survey report, voltage ratings, and load requirements established by the power system studies described in Chapter 2, Pirelli Cable Corporation prepared pre- liminary designs for 13 submarine cable crossings. The Pirelli report is included as Appendix B, and their recommendations are summarized on Table 3-3. Pirelli has recommended submarine cable designs based on EPR (Ethylene Propylene Rubber) dielectric insulation without a lead sheath. The application of EPR insulated submarine cable without a lead sheath at 138 kV would be at the forefront of cable technology. To our knowledge, at the present time there are no submarine applications of EPR at voltages exceeding 69 kv. Presently, a United States industry standard for EPR insu- lated 138 kV cable does not exist. As a result Pirelli has proposed cable designed in accordance with IEC (International Electrotechnical Commission) standards. IEC cable standards do not specify an insulation thickness. Cables manufactured according to IEC tend to have thinner insulation than do cables built according to U.S. industry standards. Another technical factor that should be evaluated when considering the use of EPR insultation is dielectric loss. EPR compounds vary from maunfacturer to manufacturer, but all EPR compounds have greater dielectric losses than do equivalent cables with more conventional insulations. See Table 3-4 for a comparison of losses for cables with different types of insulation. The Pirelli recommendation is also at variance with conven- tional cable installation because it does not include a sheath. The omission of the sheath is based on sea bed conditions iden- tified in the underwater surveys for some routes; namely, rock outcrops, boulders, and other bottom irregularities that would result in unsupported cable spans. If future underwater route surveys can find routes that are free of such conditions, then a lead sheathed cable design could be reconsidered. Proven design alternatives to EPR insulated cable are lead sheathed oil-filled, oil impregnated paper insulated or solid dielectric insulated cable with a lead sheath. At voltages of 69 kV and above paper insulated cable with a lead sheath has been widely used for submarine cable application all over the world. Based on this proven experience, we recommend that paper insulated lead sheath cables, self-contained oil filled (SCOF) for AC cable routes and oil impregnated (solid) for long DC cable routes also be considered. Other excellent alternative 3-5 Table 3-3 CABLE DESIGNS RECOMMENDED BY PIRELLI CABLE CORPORATION Segment: 2.1 2.2 2 5.2/5.4 6.1 6.5 Zot From: Skagway Haines Douglas Is. Snettisham Wrangell Narrows Duncan Canal Kake Item To: Haines Bridge Cove Young Bay Kupreanof - - Warm Springs Bay Length of Cable, Feet 78,000 277,000 27,500 420,000 5,000 6,000 190,000 Voltage, kV AC (DC) (75) (75) 34.51/ (100) 138 138 (75) Cable Typel/2/ Conductor Size, mm2 150 150 70 240 240 240 150 No. of Conductors/Cable 1 1 3 1 3 3 1 Armor3/ pew pew sw Dew sw sw DCW 0.D., in. 2.3 2.3 3.5 2.7 7.2 7.2 2.3 Weight, lbs/ft. 6.0 6.0 9.4 8.0 30.2 30.2 6.9 Segment: 8.5 8.6 9.1 10.6 11 12 From: Bell Is. Pt. Lees Ketchikan Revilla. Is. Portland Canal Mountain Pt. Item To: Revilla. Is. Revilla. Is. Grindall Pt. Pt. Trollup - Race Pt. Length of Cable, Feet 6,300 4,200 91,000 41,000 9,500 5,000 Voltage, kV AC (DC) 138 138 (75) 138 (100) 69 Cable Typel/2/ Conductor Size, min2 240 240 150 240 240 120 No. of Conductors/Cable 3 3 1 3 1 3) Armor3/ sw sw pew DCW Dcw Dcw O.D., in. 7.2 7.2 233 7.1 2.7 4.8 Weight, lbs/ft. 30.2 30.2 6.0 32.2 8.0 17.4 V/ Data furnished by Pirelli Cable Corporation 2/ All EPR insulated cables 3 Armor types: Single Wire (SW); Double Counterhelical Wire (DCW) submarine cable designs are cross-linked polyethylene (XLPE) insulated with a lead sheath and polypropylene laminated paper (PPLP) with a lead sheath. The XLPE has excellent dielectric loss characteristics (see Table 3-4) which should be considered in the long term economic analysis of the cable routes. The PPLP has excellent resistance to oil drainage which would satisfy cable route applications with high elevation differences. Table 3-4 INSULATION DIELECTRIC LOSSES FOR TYPICAL 138 kV AC 240MM2 SUBMARINE CABLE Insulation sic DF wal/ XLPE 2.4 -001 007 EPR 2.9 -003 292 Paper Insulation (solid) 3.5 -003 353 Paper Insulation (PPLD) 2ot -0007 -064 where SIC = Insulation Dielectric Constant DF Dissipation Factor wd Watts loss per conductor foot at 60 Hz 7 Reference: Neher, McGrath AEEI paper No. 57-660 "The Calculation of the Temperature Rise and Load Capability of Cable System". Submarine Cable Installation The cost estimates prepared by Pirelli include installation and are based on a turn-key type contract being contracted to, in all probability, a cable manufacturing company. It should be noted that these are preliminary estimates. Contingencies should be allowed in the installation schedules for unforeseen problems. The transport of the cables and the installation of the cables should be done, preferably in the months of May to September. Although other months may be seemingly feasible, delays due to storms and increased risks are very likely. 3-6 Submarine Cable Reliability The reliability factor of submarine cable is extremely high. In the typical application the majority of the cable is routed in deep water and should be self-protecting, not requir- ing maintenance. The shore landing sites should be chosen to minimize risk of damage. The burial of the cable in the near shore sections would prevent damage and assure that planned maintenance activi- ties are not necessary. For any sites where cable burial is not possible, or is partially successful, or where there is a need for the cables to be covered with selected granular material, in the initial years of operation it would be advisable to inspect these locations on an annual basis. This inspection should be carried out by a diver using a locator to track the cable. The diver would check for signs of cable movement which could result in chafing, cable damage, or any other potential hazard situation. Submarine Cable Costs Estimates of the cost of manufacture and installation of the submarine cables for 13 cable crossings were prepared by Pirelli based on their recommended cable designs. As shown in Appendix B, Pirelli prepared unit price estimates for the cost of one or two cables per crossing, and lump sum estimates for the mobilization, engineering and additional surveys required to implement the cable installations. Table 3-5 presents a summary of the cost estimates and gives the estimated total cost for the installation of a single cable at each surveyed crossing, except for the Portland Canal crossing (No. 11) for which two cables are required. As indicated in Chapters 1 and 6, public, agency and private contacts during the course of the study resulted in the subsequent consideration of transmission interconnections for additional load centers and/or via routes not previously consid- ered. Many of the new routes include submarine cable crossings for which no site specific cost estimates or cable designs have been prepared and, in most cases, for which no survey data is available. For these submarine cable crossings, the design and cost data provided by Pirelli were interpolated to provide data for use in comparisons of the various routes. Pirelli's unit costs and lump sum costs were examined for trends considering cable voltage, length, type and total weight of cable. For each additional cable crossing studied, new unit prices for installa- tion and new lump sum costs for mobilization and engineering and Surveys were developed. The unit prices for cable manufacture used in the interpolated cost estimates are the same as those 3=7 Table 3-5 SUBMARINE CABLE COSTS FOR SURVEYED ROUTES1/2/ Segment: 2.1 2.2 a §32/5.4 6.1 as a From: Skagway Haines Douglas Is. Snettisham Wrangell Narrows Duncan Canal Kake Item To: Haines Bridget Cove Young Bay Kupreanof = = Warm Springs Bay Length of Cable, Feet 78,000 277,000 27,500 420,000 5,000 6,000 190,000 Voltage, kv AC (DC) (75) (75) 34.51/ (100) 138 138 (100) Unit Costs in $/1000 £t1/3/4/ Manufacture Cable 18,000 18,000 30,000 25,000 105,000 105,000 18,000 Installation, 1 Cable 11,200 4,500 _ 20,000 3,500 82,000 82,000 9,300 Installation, 2 Cables 14,600 6,000 28,000 4,800 114,000 114,000 12,800 Total Cost for Single Cable, in $ Millions Mobilization!/ 6.60 6.80 1.35 7.00 1.35 1.35 6.80 Cable Manufacture 1.40 4.86 0.83 10.50 0553) 0.63 3.42 Installation 0.87 1.25 0.55 1.47 0.41 0.49 UB Ard Subtotal 8.87 12.91 2,13 18.97 2.29 2.47 11.99 Surveys!/ 0.29 0.67 0.10 0.67 0.07 0.07 0.29 Engineering1/ 0.10 0.10 0.07 0.10 0.05 0.05 0.07 Total Installed Cost 9.26 13.58 2.90 19.74 2.41 2.59 12535 1/ Data furnished by Pirelli Cable Corporation 2/ All EPR insulated cables 3/ For AC cables, 1 single cable consists of 3 conductors 4/ Per Pirelli, manufacturing costs are current and include profit and overhead. Installation costs include a 5% contingency allowance. Table 3-5 (Cont'd) SUBMARINE CABLE COSTS FOR SURVEYED ROUTES1/2/ Segment: 8.5 8.6 9.0 10 11 12 From: Bell Is. Pt. Lees Ketchikan Revilla. Is. Portland Canal Mountain Pt. Item To: Revilla. Is. Revilla. Is. Grindall Pt. Pt. Trollup - Race Pt. Length of Cable, Feet 6,300 4,200 91,090 41,000 9,500 . 5,000 Voltage, kv AC (DC) 138 138 (75) 138 (100) 69 Unit Costs in $/1000 ft1/3/4/ Manufacture Cable 105,000 105,000 18,000 115,000 25,000 60,000 Installation, 1 Cable 82,000 97,500 11,250 21,500 - 97,500 Installation, 2 Cables 114,000 178,800 14,600 32,000 178,800 178,800 Total Cost for Single Cable, in $ Millions Mobilization!/ 1.35 0.67 6.60 6.80 0.67 0.67 Cable Manufacture 0.66 0.44 1.64 4.72 0.48 0.48 Installation 0.52 0.41 1.02 0.88 1.70 0.31 Subtotal 2.53 1.52 9.26 12.40 2.85 1.46 Surveys!/ 0.07 0.07 0.29 0.10 0.07 0.07 Engineering1/ 0.05 0.05 0.10 0.05 0.05 0.05 Total Installed Cost 2.65 1.64 9.65 12.55 2297 1.58 (2 cables) 1/ Data furnished by Pirelli Cable Corporation 2/ All EPR insulated cables 3/ For AC cables, 1 single cable consists of 3 conductors 4/ Per Pirelli, manufacturing costs are current and include profit and overhead. Installation costs include a 5% contingency allowance. furnished by Pirelli for the surveyed routes. Table 3-6 shows the costs estimates developed for the additional submarine cable crossings. 3-8 Table 3-6 INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Crossing: Segment No.: Zt QA /2ie2 From: Skagway Skagway To: Haines Haines/Juneau Length, Feet 78,000 355,000 Voltage, kv AC (DC) 138 (75) Cable Data2/ Conductor Size, mm2 240 150 No. of Conductors 3 1 Weight, lbs/ft 30.2 6.0 Unit Cost in $/1000 ft Manufacture Cable 105,000 18,000 Installation, 1 Cable 20,200 3,000 Total Cost for Single Cable, in $ Millions Mobilization 6.90 7.00 Manufacturing 8.19 6.39 Installation 1.58 1.07 Subtotal 16.67 14.46 Surveys and Engineering 0.83 0.73 Total Installed Cost3/ 25.00 15.19 Lynn Canall/ Lynn Canal1/ 1/ Although the indicated routes were surveyed, consideration of various 27 EPR insulated cables 3/ Costs excluding contingencies and owners cost alternatives required interpolation of costs, Lynn Canal Lynn Canal Lynn Canal 2.1B 2.1B 25138 Skagway Skagway Skagway Haines Haines Haines 15,000 15,000 15,000 138 69 3465 240 120 70 3 3 3 302 17.4 9.4 105,000 60,000 30,000 55,900 40,000 25,900 6.60 1235 0.68 iso 0.90 0.45 0.84 0.60 0.39 9.01 2.65 (52 0.45 0.14 0.14 9.46 2.99 1.66 resulting in the estimates shown. Table 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Crossing: Lynn Canal Lynn Canal Lynn Canal Segment No.: 2.2B 2.2/2.8 2a 222.8 From: Haines Haines Skagway To: Juneau Douglas Is. Douglas Is. Length, Feet 51,000 410,000 488,000 Voltage, kV AC (DC) 138 (75) (75) Cable Datal/ Conductor Size, mm2 240 150 150 No. of Conductors 3 1 1 Weight, lbs/ft 30.2 6.0 6.0 Unit Cost in $/1000 ft Manufacture Cable 105,000 18,000 18,000 Installation, 1 Cable 27,200 3,900 3,600 Total Cost for Single Cable, in $ Millions Mobilization 6.80 6.90 7.00 Manufacturing 5.35 7.38 8.78 Installation 1.39 1.60 1.76 Subtotal 13.54 15.88 17.54 Surveys and Engineering 0.68 0.79 0.88 Total Installed Costs2/ 14.22 16.67 18.42 1/7 EPR insulated cables 27 Costs excluding contingencies and owners cost Favorite Channel 3 Juneau Green's Creek 27,500 138 240 3 30.2 105,000 40,800 Ta ble 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Crossing: Favorite Channel Segment No.: 3 From: Juneau To: Green's Cr Length, Feet1/ 27,500 Voltage, kV AC (DC) 69 Cable Data2/ Conductor Size, mm2 120 No. of Conductors a Weight, lbs/ft 17.4 Unit Cost in $/1000 ft Manufacture Cable 60,000 Installation, 1 Cable 31,270 Total Cost for Single Cable, in $ Mobilization 6.60 Manufacturing 1.65 Installation 0.86 Subtotal 9.11 Surveys and Engineering 0.46 Total Installed Costs3/ 9.57 1/7 (2) Indicates two separate ca 2/ EPR insulated cables 3/ Costs excluding contingencies Chatham Str. Chatham Str. Ten. I./Pearl 14.1 14.1 14.3/14.4 Green's Creek Green's Creek Tenakee eek Hoonah Hoonah Sitka 87,000 87,000 (2) 40,000 138 69 138 240 120 240 3 3 3 30.2 17.4 30.2 105,000 60,000 105,000 19,660 15,660 31,710 Millions 6.95 6.80 6.75 9.14 5.22 4.20 1.70 1.36 loa Wie 9) 13:538 W222 0.89 0.67 0.61 18.68 14.05 12583) ble crossings and owners cost Table 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEY ED Crossing: Ten. I./Pearl Ten. I./Chatham Fredrick S. Chatham Str. Segment No.: 14.3/14.4 14.3/14.5 5.4 7.1 From: Tenakee Tenakee Snettisham Sitka To: Sitka Angoon Kake Kake Length, Feet!/ (2) 40,000 (2) 80,000 333,000 190,000 Voltage, kV AC (DC) 69 69 (100) (100) Cable Data2/ Conductor Size, mm2 120 240 240 240 No. of Conductors 3 3 1 1 Weight, lbs/ft 17.4 17.4 8.0 8.0 Unit Cost in $/1000 ft Manufacture Cable 60,000 60,000 25,000 25,000 Installation, 1 Cable 25,230 15,660 5,000 9,600 Total Cost for Single Cable, in $ Millions Mobilization 6.65 6.80 6.95 6.80 Manufacturing 2.40 4.80 8.33 4.75 Installation 1.01 1.25 1.66 1.82 Subtotal 10.06 12.85 16.94 13.37 Surveys and Engineering 0.50 0.64 0.85 0.39 Total Installed Costs3/ 10.56 13.49 1729 13.76 1/7 (2) Indicates two separate cable crossings 2/ ‘EPR insulated cables 37 Costs excluding contingencies and owners cost Table 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Crossing: Wrngl. N./Duncan Wrangell Nar. N. Behm Canal N. Behm Canal Segment No.: 6.1 6.2 Bac 8.2 From: Petersburg Petersburg Tyee Lake Tyee Lake To: Kake Kake Swan Lake Swan Lake Length, Feet!/ (2) 11,000 3,200 3,200 10,000 Voltage, kv AC (DC) 138 138 138 138 Cable Data2/ Conductor Size, mm2 240 240 240 240 No. of Conductors 3 3 3 3 Weight, lbs/ft 30.2 30.2 30.2 30.2 Unit Cost in $/1000 ft Manufacture Cable 105,000 105,000 105,000 105,000 Installation, 1 Cable 66,440 99,600 99,600 66,440 Total Cost for Single Cable, in $ Millions Mobilization 1.35 0.67 0.67 W335 Manufacturing Tete 0.34 0.34 1.05 Installation 0.73 0.32 0.32 0.66 Subtotal 3.24 1233 1.33 3.06 Surveys and Engineering 0.29 0.13 0.16 0.16 Total Installed Costs3/ 3.53 1.46 1.46 3.22 EPR insulated cables Iwill SSS (2) Indicates two separate cable crossings Costs excluding contingencies and owners cost Crossing: Segment No.: From: To: Length, Feet!/ Voltage, kV AC (DC) Cable Data2/ Conductor Size, mm2 No. of Conductors Weight, lbs/ft Unit Cost in $/1000 ft Manufacture Cable Installation, 1 Cable Table 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Behm Canal 10.3 Swan Lake Quartz Hill Behm Canal 10.3/10.10 Swan Lake Quartz Hill Behm Canal 10.5/10.7 Swan Lake Quartz Hill Behm Canal 10.5/10.7/10.10 Swan Lake Quartz Hill Total Cost for Single Cable, in $ Millions Mobilization Manufacturing Installation Subtotal Surveys and Engineering Total Installed Costs3/ 14.08 1/ (2) Indicates two separate cable crossings 2/ +&EPR insulated cables B/ Costs excluding contingencies and owners cost Behm Canal Clarence Str. Ngiet 1372 Tyee Lake Tyee Lake Ketchikan Prince of Wales 50,000 48,000 138 69 240 120 3 3 30/52 17.4 105,000 60,000 27,200 22,600 6.80 6.70 Si25 2.88 123136 1.08 13.41 10.66 0.67 0.54 11.20 48,000 138 240 3 32.2 115,000 30,600 83,000 138 240 3 32.2 115,000 20,100 (2) 61,000 138 240 3 32.2 115,000 24,200 (2) 96,000 138 240 3 32.2 115,000 19,300 7.00 11.04 1585 19.89 1.00 20.89 Table 3-6 (Cont'd) INTERPOLATED COST ESTIMATES FOR SUBMARINE CABLE ROUTES NOT SURVEYED Crossing: Behm Canal Behm Canal Behm Canal Behm Canal Segment No.: 10.7 10.7/10.10 10.8 10.8/10.10 From: Swan Lake Swan Lake Swan Lake Swan Lake To: Quartz Hill Quartz Hill Quartz Hill Quartz Hill Length, Feet 53,000 88,000 45,000 80,000 Voltage, kV AC (DC) 138 138 138 138 Cable Datal/ Conductor Size, mm2 240 240 240 240 No. of Conductors 3 3 3 3 Weight, lbs/ft 3 2ie2) SZ) a2 32'.2 322 Unit Cost in $/1000 ft Manufacture Cable 115,000 115,000 115,000 115,000 Installation, 1 Cable 27,400 19,300 30,600 20,900 Total Cost for Single Cable, in $ Millions Mobilization 6.80 6.90 6.80 6.95 Manufacturing 6.10 10.12 Stal 7 9.20 Installation 1.45 1.70 1.38 1.67 Subtotal 14.35 18.72 13:.35 17.82 Surveys and Engineering 0.72 0.93 0.67 0.89 Total Installed Costs2/ 15.07 19.65 14.02 18.71 17 EPR Insulated cables 2/ Costs excluding contingencies and owners cost 3/ (2) Indicates two separate cable crossings Chapter 4 OVERHEAD TRANSMISSION LINE DESIGN CONSIDERATIONS AND COST ESTIMATES General This chapter describes the assumptions, criteria and para- meters used to develop the preliminary designs and cost esti- mates for comparison of the various overhead transmission line alternatives. The study is based on the climatic and terrain information available and conductor sizes determined from the system studies described in Chapter 2. The quantity of the information indicated, and the extent of engineering described below is deemed to be sufficient to permit cost comparisons and estimates to an accuracy of 20 percent. From the general climatic data available, preliminary conductor loadings were formulated and sag and tensions were calculated. These, in turn, were used as a basis for selecting suitable spans, struc- ture types and all component requirements. Subsequently, costs were estimated and compared for stand- ard line structures and a structure type was selected for recom- mendation. The prices used for all major line materials are current, and suppliers of the line structures were consulted. However, because of the general nature of this study, further investigation and study would be required to establish the final design criteria for particular segments of the line prior to construction. Line erection costs were estimated based on salary rates, obtained from the Alaska Labor Department in Juneau, and assumed construction production rates and manpower needed. Previous studies for the S.E. Intertie and actual line construction costs supplied by the Power Authority were studied and compared to computed costs as applicable. Climatic Conditions For preliminary studies, the average climatic conditions, shown below, were used. It should be recognized that considera- tion of higher wind conditions and heavier ice accumulation on conductors may be required in final design of particular sec- tions of the line, such as the White Pass portion of the Skagway - Whitehorse interconnection. The following table shows the conditions used to compute conductor loadings: Table 4-1 ASSUMED CLIMATIC CONDITIONS FOR OVERHEAD TRANSMISSION LINES1/ Strength Condition Temperature °F Limit (REA) Everyday temperature 40 33.3% Initial Max. radial ice 1.5 in. 30 70% Max. wind 120 MPH 40 70% Max. conductor temperature 120 -- NESC heavy loading 0 50% NESC minimum temperature 0 25% Final Vf To establish minimum clearance requirements seven feet of snow accumulation was assumed. Structure Foundations Direct embedment of the line structure poles is assumed for construction of the lines. With exception of deep muskeg deposits, pole embedment in normal inorganic soil is taken as ten percent of the pole length plus two feet. For poles set in rock, the embedment length is assumed to be ten percent of the pole length. For shallow muskeg deposits, pole embedment will be governed by the depth to underlying stable soils. For deep muskeg areas, raft or similar type foundations in conjunction with guying could be used, with log anchors for pole guys. Screw or rock anchors would be used for guys in inorganic and rock soils, respectively. If steel line structures are used, particularly the free standing single pole type, caisson foundations would be required for heavily loaded (angle or dead end) structures in normal soils. Rock anchor foundations would be used for rocky areas and, in general, pile foundations would be required for deep muskeg areas. Anchor bolts would provide the connection between the foundation and the pole for these types of foundations. 138 kv AC Overhead Lines In accordance with system studies presented in Chapter 2, 138 kV was selected as the voltage level for major AC trunk line routes. 4-2 Conductors Based on the system studies, described in Chapter 2, it was determined that a 336 kCM ACSR conductor would meet the electri- cal requirements for the 138 kV lines. However, because of Southeast Alaska's terrain and weather conditions, which are considered severe, the larger 397.5 kCM ACSR conductor was used for cost estimating purposes. It is believed that no conductor smaller than 336 kCM ACSR should be used for these lines. The actual conductor size can be established in the final design stage, but no appreciable reduction in cost would be realized by using the smaller conductor. Because the isokearaunic level is very low (1-2) in the study area, a shield wire will not generally be required on the lines. The approaches to line terminals, however, should be shielded for a distance of 1.0-1.5 miles. Insulators An insulation level equivalent to eight standard 5-3/4" x 10" porcelain insulator discs per string was selected for the 138 kv AC lines. Insulator assembly characteristics are shown in Table 4-2. Table 4-2 138 KV AC INSULATOR ASSEMBLY CHARACTERISTICS Nominal Voltage (L-L) 138 kv No. of Insulators 8 Low Frequency Dry/Wet 485/760 kv Impulse Pos/Neg 780/760 kv Leakage Distance 92 inches ME Strength 20,000 lbs. For cost estimating purposes, the use of polymer insulators was assumed. Although the price quoted for the polymer type is higher than that for porcelain, polymer insulators are recom- mended because of their light weight, strength and construction/ maintenance advantages. The comparable cost and weight per assembly of the two types of insulators are shown in Table 4-3. 4-3 Table 4-3 PORCELAIN VS. POLYMER INSULATORS FOR 138 KV AC CONSTRUCTION Item Porcelain Polymer Weight, lbs per assembly 110 30 Cost per assembly $140 $170 Line Structures To select the appropriate line structure for the main trunk Intertie transmission lines, a cost comparison study was made for the 138 kV AC lines. The three types of structures consid- ered were Wood Standard H-Frame with X-bracing, Steel H-Frame and Single Steel Pole, all directly embedded. The selection only these three structure types for this study is based on line construction costs in Alaska. The labor erection cost is high and in general represents the larger part of the total construc- tion cost due to access, terrain features and climatic condi- tions. Therefore, the least expensive alternative for line con- struction should be the one which requires less labor and time. Lattice galvanized steel towers were not considered because they require more labor for their erection and foundations than the selected structure types and are considered by many to be objectionable because of their visual impact. Wood single pole structures, although the least expensive alternative per struc- ture, were also rejected because of their limited span length, which can present difficulties for their spotting in the rough terrain encountered along many line routes. Furthermore, the larger number of wood single pole structures required would also increase the labor required for their erection. The assumed minimum vertical clearance for the main trunk lines is 23 feet, in accordance with NESC (National Electrical Safety Code) guidelines for 138 kV AC line voltage along roads in rural areas. An assumed snow accumulation depth of seven feet is used in conjunction with the minimum clearance to estab- lish the average structure height for the cost estimates. Sag calculations for various span lengths for the 138 kV lines, under the assumed conditions, are given on Table 4-4. Economical span lengths have not been calculated for the selected structure types because this is not considered neces- sary for cost comparison purposes. Wood H-Frame Wood Structure. The standard 138 kV Wood H-Frame structure with X-bracing (see Figure 4-1) is the basic 4-4 -PREPARED FOR —LARK 397.5 KCM 30/7 STKAND ACSK CONDUCTUK HEAVY LUADING HARZA ENGINEERING COMPANY . USING STRESS=STRAIN DATA AND COMPUTER PROGRAM FRUM ALCUA CROSS SECTIONAL AREA ULTIMATE STRENGTH = ELECTRICAL SAFETY CODE CONSTANT = OVER ALL OIAMETER = ALASKA POWER AUTHORITY STRESS=STRAIN DATA FROM CHART NO. ENGLISH UNITS SPAN= 600.0 FEET OESIGN POINTS TEMP,F ICEsIN, 0.0 0.0 0.0 40.0 40.0 40.0 -40.0 120.0 SPAN 0.500 4.000 1,500 0.000 9.000 0.000 0.000 21,000 0.000 0.000 0.000 6,000 0.000. 0,000 0.000 0.000 700,0 FEET DESIGN POINTS TEMPsF ICEsIN. WIND/LBSF ~0.0 0.500 _4.000 0.0 0.0 40.0 40.0. 40.0 1,500 0.000 0.000 0,000 0.000 21,000 0.000 0.000 0,000 6,000 740.0 0,000 0.000 120.0 SPAN 0.000 0.000 1000,0 FEET DESIGN POINTS TEMPeF ICEsINe WIND-LBSF -.960_. 0.500 4,000 0.0 0,0 40,0 40,0 40.0 -40.0 120.0 1.500 0,000 0,000 0,000 0.000 21,000 0.000 0,000 0.000 6,000 0.000 0,000 0.000 0,000 WIND-LBSF Table 4-4 0.30000 0.3649 § IN. 20300.00000 LB. 0.6060000 IN. 1-773 FINAL SAGs FT. TENSION, LB. 9.78 717k. 16,84 13214, 5,52 5075, 11,04 6294, 7,06 3973, 7.76 4306, 4,36 6429, 8.62 3180, FINAL SAG, FT. TENSION, LB. 12.93 7386. 21.34 14200, 7,82 4881, 14,36 6590, 9.58 3964, 10,515 4320, 6.27 | 6088, 11.33 3370. FINAL SAGr FT. TENSION, 34,35 5097, 43,79 14200, 26.84 2711. 36.08 5379. 30,11 2598, 31.30 2978, 27,56 2836, 32.59 2402. SAG AND TENSION DATA 070 35.32 65,09 25,00 31.01 19,57 21.21 31,67. 15.606 0/0 30.39. 69.95 24,04 32.46 19,62 21.31 29.99 16,60 070 26,06 69.95 13.35 26.50 12,60 14,67 13.97 11.83 1,76 16,64 3,51 8.45 4,02 4,70 3,12 5.66 9,99 ~ 21.34 4,59 10.77 5.21 6.07 Baad 7.10 SAG CALCULATIONS FOR 138 KV AC OVERHEAD LINES INITTAL SAG, FT. TENSION, LB. 9027. 13214, 7966, #e2l. 6960. 7103. 6970, 4957. INITIAL SAG, FT. TENSIUNe LB. 9546, 14200, 8316, 6761. 7325, 7489, 9272, $375. INITIAL SAGr FT. TENSIONs 28,91 43.79 21.81 30.42 24,05 25.05 19,57 28.32 6758, 14200, 3578. 6366. 3249. $713. 3985, 2760, 0/0 44,47 65.09 39.34 40.50 34.32 34,99 44.19 24,42 0/0 47.03 69.95 40,96 43.26 36,08 36,89 45.67 26.48 0/0 33.29 69.95 17.603 31.36 16.00 18.29 19,03 13.60 RESULTANT 1.556 4.924 0.623 1.542 0.623 0.742 0.623 0.623 RESULTANT 1,556 4.924 0.623 1.542 0.623 v.742 0,623 0.023 RESULTANT 1.556 4.924 0.623 1,542 0.623 0.742 0.025 0.623 FIGURE 4-1 | /4-6” /4’-6" —_—_____gi9___ ee _l'’= | > | \ = _ 2 > » \ --6%/5Q FT WIND © 40°F SWING NOTE. SIMILAR STRUCTURE YA St FOR DC B/POLAR YB FT. LINE WITH GROUND i: MIN, CLEARANCE RETURN CONDUCTOR CONDUCTORS € 397.5 KCM ACSR HORIZONTAL SPAN 700 £7. | GROUND LINE Dy TET, = = os , pat 7 ah ; MSFT > SI SYVBTEY 8 Nh> iS = 8’ EMBEOMENT | SAG 46’-0O” 60’POLE SHOWN RIGHT OF WAY 35’-0" TOTAL ROW WIDTH 7OFT (G.5 ACRES (MILE) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY 138KV AC WOOD H-FRAME TANGENT STRUCTURE type selected for the cost comparison. Based on preliminary calculations, the span capability of the structure with ANSI class poles is estimated to be 700 ft. considering the following loads: e NESC Heavy Loading e 120 MPH Wind Load e 1-1/2 Inch Radial Ice Load Without Wind In accordance with suppliers' price quotes, the material cost per structure delivered to Ketchikan is as follows: Framing (crossarms, braces, bolts, etc.) $ 900.00 Poles 1050.00 Total $1950.00 The total weight of the structure would be approximately 5100 lbs. using the 60 ft. poles required for the assumed clearance. Steel H-Frame Structure. The steel H-Frame structure con- sidered would be two steel poles without X-bracing and one tubu- lar crossarm (see Figure 4-2). For the loadings shown above, the steel structure weight would be 5,200 lbs., approximately the same as the Wood H-Frame alternative. The span capability, however, would be 1000 feet compared to 700 feet. Therefore, for the same weight, the number of structures per mile will be reduced from 9 to 6, with a corresponding reduction in construc- tion labor cost. The price of the tangent structure quoted by a U.S. manufacturer is $6,800 including freight to Ketchikan. To accommodate the bigger sag for the longer span, the height of the structure would be increased by 10 feet compared to the Wood H-Frame. The steel H-frame structure considered would be constructed of bare CORTAN-A588M steel with a coal tar coating on the embedded length. Clips for removable ladders and a 2 foot ground sleeve would be provided. Single Steel Pole Structure. A third structure type which could be used for the 138 kV AC lines is a Single Steel Pole structure with free-standing shaft and three crossarms as shown on Figure 4-3. Based on the same loading as above and 1000 foot span, the estimated structure weight is 4,500 lbs. The struc- ture would have the same features as given for the Steel H-Frame structure. The supplier's estimated price for a tangent pole is $5,000 including freight to Ketchikan. The total length of the pole would be in the range of 80-85 feet. 4-5 IT 60 ; TT6" , FIGURE 4-2 ~T CONDUCTORS 397.5 KCM ACSR HORIZONTAL SPAN 1000 FT. 70' POLE SHOWN RIGHT OF WAY GROUND L/NE /0' EMBEDMENT TOTAL ROW W/DTH /00FT ( 12.1 ACRES/M/LE } ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY 138KV STEEL H-FRAME TANGENT STRUCTURE WARZA encneeans covesny ocrToee= 1967 STEEL DAV/IT FIGURE 4-3 CROSSARMS 7-6" CONDUCTORS 397.5KCM ACSR HORIZONTAL SPAN 1000 F7. S H : . Q 3 w te _ ; % g = a 3 % ue 9 i ale 6 x GROUND LINE WW Z OO IES /3'EMBEOMENT 38-6" - 3e'- 6” TOTAL ROW W/IOJH 77 FT (9.4 ACRES /MILE) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY 138KV STEEL POLE TANGENT STRUCTURE WARZA encretnns covecny OCTOBER 7957 — LS 138 kV Line Structure Cost Comparison. Estimated basic costs per mile for conventional line construction for selected three alternatives are shown in Table 4-5. The costs shown are for comparison purposes only and do not include the costs of right of way acquisition, clearing, engineering, administration, or contingencies. Table 4-5 LINE STRUCTURE costsl/ Wood Steel Single H-Frame H-Frame Steel Pole Number of structures per mile 9 6 6 Number of pole embedments per mile 18 12 6 Estimated weight of struc- tures per mile, lbs. 45,900 46,800 40,500 Estimated cost of construc- tion per mile $101,700 $112,600 $109,800 Estimated cost of materials per mile $ 54,000 $ 80,000 $ 73,000 Total cost per mile2/ $155,700 $192,600 $182,800 7 Composite costs for 75/15/10 percent of normal/rock/muskeg foundation conditions. 2H Without cost of ROW, clearing, contingencies, administra- tion, or engineering. As shown in the table, the least cost alternative is the Wood H-Frame construction alternative followed by the Single Steel Pole. The final choice between the two can be made only during the final line design stage when the soil conditions along the route should be known and analysis of the cost of the structures and their foundations is performed. For this compar- ison, the assumption of 75/15/10 percent of normal/rock/ muskeg soil conditions was made. Other parameters which will influence the selection of steel versus wood structures will be the line maintenance conditions and construction access. For helicopter assisted line construction in roadless areas, for example, steel poles may have a cost advantage because they are lighter per z mile, and require a fewer number of structures to transport. 4-6 For this evaluation, however, the Wood H-Frame structure is the least expensive alternative and was selected for use in the cost estimates of all 138 kV overhead lines. 69 kV AC Overhead Lines Based on the system studies described in Chapter 2, 69 kv AC overhead lines were selected for major branch lines. They would be of the single wood pole type, directly embedded. The selected basic line features are as described in the following paragraphs. For estimating purposes this configuration was also used for 34.5 kV branch lines where applicable. Conductors and Insulators Size 4/0 AWG ACSR conductors were selected for cost esti- mating proposes. This is the next larger size conductor to the minimum for 69 kV voltage class lines according to REA (Rural Electrification Administration) Standards. Calculations of con- ductor sag were made for the 69 kV lines based on conductor tensions limited to recommended safe values for aeolian vibra- tion and maximum stress. Line insulation equivalent to four standard 4-3/4" x 10" porcelain insulator discs was selected for the 69 kV AC lines. Because polymer line post insulators are expected to provide necessary resistance to unbalanced load for the conductors and spans assumed, they can be used for these lines also. Compared to the porcelain type, polymer insulators are lighter in weight, more resistant to vandalism, easier to maintain and result ina reduction of ROW width. Therefore polymer line post insulators are the selected type for this analysis. Line Structures Based on the same loading conditions as for the 138 kv lines, the 45-50 ft. ANSI Class 2 pole is estimated to be required for an assumed 350 foot average span. Fifteen struc- tures per mile would be required. A typical structure configu- ration is shown on Figure No. 4-4. DC Overhead Lines Two DC transmission voltages, 75 kV and 100 kV, would be utilized in the Intertie System as presently conceived. The overhead DC lines for this voltage class will be very similar to the 69 kV AC overhead lines. The main differences would be that a single conductor would be used for monopolar (or two for bipolar) systems instead of three conductors needed for AC lines and that the insulators used must be suitable for DC operation. Figure 4-5 shows a typical 100 kV DC wood pole tangent struc- 4-7 FIGURE 4-4 CONDUCTORS 9/0 AWG ACSR HORIZONTAL SPAN #00 F7. 60'POLE SHOWN RIGHT OF WAY GROUND LINE 8 'EMBEOMENT, TOTAL ROW W/OTH 40F (4.9 ACRES/MILE ) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY 69KV AC WOOD POLE TANGENT STRUCTURE WHARZA encnesanc comenny | OCTOBER 1957 FIGURE 4-5 GROUND RETURN a SECOND CONDUCTOR FOR BIPOLAR L/NE TOTAL ROW W/OTH 50 FT (6.0 ACRES/MILE) CONDUCTOR 397,5 KCM ATSR HORIZONTAL SPAN 700 F7. 60'POLE SHOWN 46'-0" FRIGHT OF WAY 20-0" TOTAL ROW WIDTH 40FT (4.9 ACRES /MILE) ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY MONOPOLAR 100KV DC WOOD POLE TANGENT STRUCTURE HARZA Encnetanc covect, - OCTOBER 12¢7 ture. Spans for the DC lines were assumed to be 700 feet mono- polar lines and 400 feet for bipolar lines. Where three conduc- tors are required (bipolar plus a sea return conductor) H-frame structures similar to those previously described could be used. Conductors Size 397.5 kCM ACSR conductors, the same as those selected for the 138 kV AC lines, were assumed for the DC circuits. Insulators The contamination severity and leakage resistance of insulators are the most important parameters for selection of DC line insulation. For the Southeast Intertie area salt contam- ination should be considered. The insulation failure for DC lines, in general, can occur as a result of the wetting of con- tamination by fog, or mist, after a protracted dry period. The process of failure starts with increased leakage currents which heat the insulator surface and produce so-called dry bands. Then, under the voltage stress, arcs over the dry bands occur between low resistance areas with resulting cascading flashover and insulation failure. Therefore, one of the main parameters to consider in selecting DC insulators is the leakage distance provided by the insulation. For this analysis, suspension polymer insulators with a leakage distance of 1.0 in./kV line to ground (100 inches total for a 100 kV line) were assumed. The exact type of insulators to be used on DC lines will be selected during the final line design. Vertical Clearance The minimum ground clearance of 23 feet was used to estab- lish the DC line structure height requirements. This clearance was calculated in accordance with NESC requirements for 100 kv DC voltage in areas with vehicular traffic. ROW Width & Minimum Clearing Requirements The right of way (ROW) for transmission lines must be of sufficient width to provide an environment for safe and reliable operation and maintenance of the line. The ROW widths recom- mended herein were estimated based on NESC requirements to pro- vide minimum clearance from deflected conductors to construction at any place on the edge of the ROW, based on conductor deflec- tions for average spans and swing under 6 lbs/sq. ft. wind pressure. 4-8 For the line voltages recommended for the Southeast Inter- tie (maximum 138 kv AC or 100 kV DC), the Electrical Environ- mental Effects are not expected to be governing and were not considered in selection of ROW width. For example, electro- static field at ground level for 138 kV AC lines will be much less, compared to that allowed for higher voltage lines and, as such, should not present a problem. At the most, only Radio Interference (RI) from the lines may have adverse effects at particular locations, and, if warranted, would be addressed during design stages. The clearing of ROW preferably would be held to a minimum (Fig. 4-6), and is done for the following three main reasons: 1) To facilitate the erection of the line structures. A minimum cleared radius at each site would be required to assemble the materials and maneuver the erection equipment. 2) To allow efficient installation of conductors. Normally, minimum width stringing trails should be cleared to allow the pulling of the conductors. Where vegetation is light bulldozer clearing may be per- formed. Forested areas will require clear cutting. The use of helicopters for stringing would reduce clearing requirements between line structures. 3) To provide adequate electrical clearance to the energized line. The clearances provided are in accordance with NESC requirements. Right of way widths for the line configurations considered and the acreage of right of way per mile of line are given on Figures 4-1 through 4-4. Based on information provided by the Alaska Power Authority an allowance for land and land rights of $7000.000 per mile of overhead transmission line is included in the cost estimates presented herein. Estimated Construction Costs for Overhead Transmission Lines To facilitate the route selection for each transmission segment and the economic analyses of the various intertie system alternatives, comparative cost estimates were prepared for each type of overhead construction required. Because, site specific information, such as foundation conditions, is not available these estimate are considered preliminary. Per mile costs were developed for the following line configurations: 1. 138 kV AC Wood H-Frame (also DC bipolar plus sea return) 4-9 CLEARING AT MID SPAN FIGURE 4-6 CLEARING AT STRUCTURE SITE Ce = 7 gat tat | oe ROW W/OTH HARZA enonesnins covesny OCTOBES 197 AS REQUIRED FOR STRUCTURE ERECTION OR FIRE HAZARD REASONS AS REQUIRED FOR STRING/NG ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY MINIMUM CLEARING DIAGRAM 138KV STRUCTURE 2c 69 kV AC Wood Single Poles 3. 100-75 kV DC Wood Single Poles a. Monopolar DC line b. Bipolar DC line The per mile cost used for 34.5 kV construction is the same that estimated for the 69 kV AC lines, for this study. For each line configuration considered, the cost of con- struction along existing roads, using conventional methods and in normal soil conditions, was estimated. This basic per mile construction cost was then modified to develop estimated costs for construction under adverse conditions, such as rock founda- tion, muskeg foundation, or limited access conditions. For the purposes of this report, all limited access transmission lines are assumed to be constructed using helicopter construction techniques. Calculated manhour costs and the estimated manhours requir- ed for particular construction operations were used to arrive at the basic average line construction cost per mile. Installation of the transmission line requires three labor- intensive operations: structure location and setting; pole-top assembly installation; and conductor stringing. Determination of manhours required for these three operations depends on production rates and local conditions. The production rates used for this analysis were developed based on information from contractors, previous reports and published data. Local condi- tions, different erection procedures and equipment were consid- ered. For example, the hauling costs for steel poles can be almost double the hauling cost for wood poles because steel poles must be handled in a manner to prevent denting and cannot be dragged. Pole top assembly installation time depends on the type of line structure utilized. Pole top assemblies for single poles are more complex than those for H-frame construction and consequently require more installation time. For stringing by the tension method, line accessibility is the major factor affecting the cost of line stringing. Adverse conditions can increase the time required for stringing to as much as double the normal time. Structure clipping and deadend making depend on the number of structures in the line so that the crew time required for these operations is proportional to the number of structures per mile. The basic construction costs developed include the follow- ing: 4-10 lie Labor cost, based on Alaska Department of Labor infor- mation adjusted for 60 hour work weeks, plus payroll burden and fringe benefits, and including allowances for mobilization, demobilization and lodging. 2. Work force and construction time required. For each line configuration, the crew composition and produc- tion rate was estimated for material hauling, excava- tion, structure assembly and erection, and conductor stringing. Se Structure type and number per mile, as described previously. The estimate is based on tangent struc- ture construction and adjusted to account for angle, dead end, and crossing structure construction. 4. Line material costs. The cost estimates are based on current manufacturer quotations plus an allowance of 25% for shipping and handling. big Contractor's profit and overhead, assumed to be 45% of total labor costs. Separate per mile costs were developed for rock and muskeg foundation construction and for helicopter construction. The costs developed for helicopter construction assumes transpor- tation of all materials, equipment and crew using either a Bell Model 212 or 205 for the hauling materials and setting of line structures and a Hughes Model 500 for assistance during conduc- tor stringing and transportation of personnel. Table 4-6 shows the basic per mile costs for four trans- mission line configurations. Table 4-7 gives the per mile cost for construction in rock foundation areas and also for muskeg area construction. The estimated additional cost for trans- mission line construction with access solely by helicopter is based on-the number of line structures required per mile for each type of line configuration. The additional per mile costs range from $20,000 for 138 kV AC construction to $10,000 for monopolar DC lines, regardless of the foundation conditions encountered. Estimated clearing costs are based on complete removal of timber and slash from the transmission line right of way. Table 4-8 shows the estimated per mile cost for the various line con- figurations considered. 4-11 Table 4-6 OVERHEAD TRANSMISSION LINES BASIC CONSTRUCTION PER MILE cosTs_/ $ Per Mile 138 kV Wood 69 kV Dc Dc H-Frame Wood Pole Monopolar Bipolar Structure Foundations/mi 182/ 15 9 14 Labor Stringing $ 51,000 $ 45,000 $ 25,000 $ 39,000 Struct. Erect. 43,000 40,000 30,000 38,000 Total Labor $ 94,000 $ 85,000 $ 55,000 $ 77,000 Materials Conductors & Accessories Line Conductors 13,800 6,500 4,600 9,200 Insulators, Hardware and Miscellaneous 7,700 12,100 2,500 7,400 Subtotal $ 21,500 $ 18,600 $ 7,100 $ 16,600 Poles & Fixtures Poles 26,500 16,000 9,000 16,000 Guys, Anch. & Other Mat. 6,000 3,400 2,900 3,400 Subtotal $ 32,500 $ 19,400 $ 11,900 $ 19,400 Total Material $ 54,000 $ 38,000 $ 19,000 $ 36,000 Basic Construction Cost3/ $148,000 $123,000 $ 74,000 $113,000 V/ Construction along existing roads with normal soil founda- tions. 2/ Nine structures per mile. 37, Excludes the costs of right of way acquisition, clearing, engineering, construction management and contingencies and owner's costs. Table 4-7 OVERHEAD TRANSMISSION LINES PER MILE CONSTRUCTION COSTS IN ROCK AND MUSKEG FOUNDATION AREAS $ Per Mile 138 kV Wood 69 kV Dc pc H-Frame Wood Pole Monopolar Bipolar Structure Foundations/mi 18 15 9 14 Rock Foundation Labor Stringing $ 51,000 $ 45,000 $ 25,000 $ 39,000 Str. Erection $ 73,000 62,000 48,000 60,000 Materials 54,000 38,000 19,000 36,000 Per Mile Construc- $178,000 $145,000 $ 92,000 $135,000 tion Costs2 Muskeg Foundation Labor Stringing 51,000 45,000 25,000 39,000 Str. Erect. 84,000 71,000 55,000 68,000 Materials 57,000 39,000 20,000 38,000 Per Mile Construc- $192,000 $155,000 $100,000 $145,000 tion Costs2 VW, Construction along existing roads. 2/ Excludes the costs of right of way acquisition, clearing, engineering, construction management and contingencies and owner's costs. ve Table 4-8 ESTIMATED CLEARING COSTS FOR VARIOUS TRANSMISSION LINE CONFIGURATIONS Transmission Line Cost per Mile, $ 138 kV Wood H-Frame 85,000 69 kV Single Wood Pole 54,000 DC Monopolar 54,000 DC Bipolar 70,000 Chapter 5 SUBSTATION DESIGN CONSIDERATIONS Introduction Substations will be required at each load center served by the Intertie, to step the transmission line voltage down to the level of local subtransmission or primary distribution voltage Substations will also be required at locations where two systems having different operating voltages terminate, such as at Swan Lake (115 kV) for the interconnection with Tyee Lake (138 kv). At the interface of AC and DC transmission segments, sophisti- cated manned facilities called converter/inverter stations will be required. At the junction of spur lines with the main trunk intertie transmission line, switching stations will be required if all of the line voltages are the same; if not, a substation, with a transformer, will be required. AC Stations Substations and switching stations for the Intertie should be designed using reliability criteria consistent with that used to guide the design of the entire Intertie System. Accordingly, for main trunk line substations, important to the functioning of the entire Intertie, a main and transfer bus arrangement is recommended. This arrangement has sufficient redundancy to allow scheduled maintenance or unscheduled outage of circuit breakers with no detrimental affect on System operations. Figure 5-1 shows a one-line diagram of a typical 138 kV AC main line substation. For substations on radial lines from the main trunk line, less rigid reliability criteria can be applied. Outages at these facilities would affect the load centers located down- stream of the problem facility, but would have no detrimental affect on the operation of entire Intertie System. Thus, in the interest of economy, a simpler substation arrangement is justi- fied. Figure 5-2 shows a typical radial line substation arrangement. Oil retention facilities are required at substations to contain any oil spillage. The substation components utilizing oil are transformers and circuit breakers. To minimize the size of the oil retention facilities, minimum oil circuit breakers or SFg circuit breakers should be specified. Therefore, the capacity of the oil retention system need only be adequate to hold the transformer oil. FIGURE 5- 5 MVA Transformer To Greens Creek Disconnect Switch (typ) 138 KV T.B. Circuit Breaker (typ) 10 MVAR 138 KV M.B. To Existing 12.4 KV Sub. o © x o oso fo ec oc rF a o - HOONAH WEST ROUTE SUBSTATION ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY TYPICAL 138 KV AC MAIN LINE SUBSTATION WARZA encresainns comeany © ocTOBER 257 ae FIGURE 5-: By-Pass Circuit Breaker (typ) Switch (typ) | 5 MVA Transformer To Angoon To Hoonah To Existing 12.4 KV Sub TENAKEE SPRINGS SUBSTATION ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY TYPICAL RADIAL LINE SUBSTATION WHARZA ENG'NEERNG CONMBONY CCTOBER 1967 DC Convertor/Inverter Stations Several segments of the Intertie necessitate the use of DC converter stations for either system reliability or due to the length of the required submarine cables. Two DC system configu- rations are recommended; the monopolar sea return and the bi- polar sea return configurations. The monopolar configuration, as the name implies, has one conductor energized and the return current path is through the sea and ground. As discussed in Chapter 2 this simple system is recommended for all the DC locations except the Quartz Hill - Kitsault interconnection. The bipolar system is recommended for this segment. The bipolar configuration utilizes two poles with one or more converters per pole at each terminal. There are two con- ductors, one per pole at each terminal. The midpoint between the converters at each end are grounded. The main components of the DC convertor station are shown in Figure 5-3. These components are as follows: . Convertor transfer . AC Filter . Shunt Capacitors e Convertor ° Smoothing Reactor e Dc Filter Au PWhH— The converter transformer is the link between the AC and the DC systems and is designed to provide an ungrounded, voltage source for the converter bridge. The tranformer is a single- phase three-winding transformer; one primary and two second- aries. The primary windings are connected to the AC bus ina wye configuration. One secondary winding is connected wye and the second winding is connected delta. The voltage induced in the delta winding has a waveform 30 degrees out of phase with the one induced in the other winding, such that the two wave- forms taken together form a six-phase system. Converter stations tend to inject harmonics into the AC system. The AC filters and shunt capacities reduce distortion in the AC system and provide var support for the converter. The filter shunts the impedance of the network to ground and thereby shunts the harmonics generated by the converter bridge to ground. The converter will have two valves for each electrical phase. Each valve has a number of thyristors connected in 5=2 FIGURE 5-3 Smoothing TRANSMISSION CONVERTER Reactor STATION CONVERTER STATION Converter Transf. Converter DC Filter rb AC Filters RP Re Rs es re nw Re te nw nn rr rw ew we f" Control System t Shunt Capacitors ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY CONVERTER STATION - MAIN COMPONENTS WHARZA encreeninc company OCTOBER 1987 series to block the voltages and conduct the currents that are characteristic of the converter. The smoothing reactor is used to smooth ripples in the DC output and to limit lightning and switching surges from the DC circuit to the thyristor valves. The DC filters are essentially shunt capacitance connected across the DC line to control and/or remove the 3rd, 12th and higher harmonies. Station buildings are required to house the various com- ponents of the converter. The DC converter stations planned for this system are relatively small. Therefore, components such as the thyristor valves, main control, the AC relaying system con- trol for the AC filter valve arrestors, grounding switches and the auxiliary electrical and mechanical systems can be housed in a single converter building. Space requirements of monopolar terminals with an AC volt- age rating up to 138 kV are approximately 200 ft by 300 ft. Requirements of bipolar terminals with an a-c voltage rating up to 138 kV are approximately 330 ft by 330 ft. See Figure 5-4. The required area is in addition to the area required for the AC yard. Local Loads and Voltages Where feasible, existing substations should be expanded to facilitate connection to the Intertie System. Table 5-1 lists the present transmission or distribution voltage at the various load centers considered and gives the assumed design capacity of the transformers required at each, if interconnected to the System. Since Juneau, Ketchikan, Wrangell and Petersburg are already served by "Intertie" generation facilities, any future upgrades of substations serving these communities, are assumed to be required in all cases considered. Consequently, the cost of improvements or maintenance of these existing facilities has not been addressed or included in this study except where modi- fications are required to accommodate a particular Intertie alternative. Substation Costs Cost estimates for substation facilities and HVDC converter/inverter facilities were developed for each load center under each of the various Intertie alternative plans considered. The estimates for the required equipment are based on current manufacturer quotations and include allowances for installation, contractor's profit and overhead, associated civil 5-3 FIGURE 5-4 SHUNT CAPACITORS—!!th FILTER 13th FILTER ay Tass REACTORS a —_ooe a iB UO U RESISTORS 4 Ye dl —~)>L +l? ~ ~~) +o ~© REACTORS - ~O-L ++ CAPACITORS | le @ G ah ri aL] < > c < m =x > c r lol Se ¢ TRANSFORMERS | 4 S/ a/ FS iy i} TO AC SWITCHYARD TOWER € SWITCH RESISTORS ~{ Tt} [} O O REACTORS . -~ ~)-{ 1) o” So rT 4 r) () [ke shunt | | Ct FO REACTORS 0-5-1 _35-0 maa ith Fter om Fore UU L ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY TYPICAL BIPOLAR CONVERTER STATION WARZA excnetenis comecny - OCTOBER 1887 Table 5-1 LOAD CENTER TRANSMISSION/DISTRIBUTION VOLTAGE AND DESIGN PEAK LOA Design Load Center Voltage Peak Load V MVA Skagway 2.4 3 Haines 34.5 5 Juneau Area2/ NA NA Greens Creek Mine 4.16 5 Hoonah 12.47 5 Tenakee Springs 12.47 5 Angoon 12.47 5 Sitka 69 30 Kake 2.4 3 Petersburg2/ NA NA Wrangel12 NA NA Ketchikan2/ NA NA Prince of Wales Island4/ 69 10 Quartz Hill Mine4/ 34.5 100 Metlakatla 12.47 10 Design peak loads furnished by Alaska Power Authority; high forecast, year 2006. Existing facilities assumed upgraded as required. Assumed 69 kV Intra-Island Transmission system serving Thorne Bay, Hydaburg and Klawock/Craig. Assumed 34.5 kV local system. 7 works, and shipment of the required equipment and materials to Alaska. Communications The successful operation of an interconnected generation and transmission system is dependent on an adequate communica- tion system. The communication system will provide for the transmission of critical information. Three communication func- tions need to be addressed: (1) relay protection, (2) system control and data acquisition (SCADA), and (3) voice. The installation of submarine cables provides an opportuni- ty to install a communication medium as part of the cable design. Power cable manufacturers offer cable designs that include fiber optic cables built into the power cable assembly. For long submarine cable runs the fiber optic cable can replace difficult microwave links. Long over-water microwave links are prone to signal fading problems. With fiber optic cables, however, the fading problem encountered with microwave over-water transmission can be avoided. Therefore it is recommended that fiber optic communications be considered when detailed design studies are undertaken for the Southeast Intertie system. For the purposes of this study a dedicated microwave system with channel diversity is assumed to be the primary mode of communication for the Intertie DC alternatives. Back-up would be provided with communications channels leased from Alascom and other communication companies. For the new AC interconnections, leased communication channels are assumed to be the primary communication mode. For existing AC links, the existing com- munications systems are assumed to be adequate in some cases and assumed to require upgrading in others. Communication costs, based on those presented by Teshmont Consultants Inc. their 1982 report for the Alaska Power Adminis- tration, are included in the cost estimates for selected alter- natives given in Chapter 7. 5-4 Chapter 6 SEGMENT ROUTE SELECTION Approach The approach used to select preferred transmission routes for economic analysis consisted of the following six steps: Identify study segments Establish route selection objectives Define evaluation criteria Identify route alternatives for each segment Collect evaluation data and Agency comments Compare alternatives and select preferred route Du PWNhN— Steps one through three are general route selection steps; steps four through six were applied to each study segment iden- tified in step one. It is important to keep in mind when reading this chapter that the intent of this study was to determine the feasibility of a southeast Alaska intertied transmission system and its general configuration. The magnitude of the study, in terms of geographic area covered, made detailed, site-specific resource investigations infeasible under the constraints of the project. Therefore, route selections for this study were based on evalu- ation of existing information from various sources. For this study, preference was given, in most cases, to the more economical route alignment unless technical or environ- mental factors were judged to clearly outweigh such a selection. Two reasons exist for this economic bias. First, the emphasis of this study is on determining the feasibility of an intertied system, which is based principally on energy supply and demand and financial incentives. If a least cost alignment is evalu- ated and determined not be viable, then neither will a more costly, but perhaps environmentally more acceptable alignment. Secondly, since detailed studies were not possible, environ- mentally or technically preferred routes could not be selected with high degrees of confidence. Given the magnitude and potential for significant impacts of this project, detailed technical and environmental resource investigations will need to be conducted for those segments that are recommended in the final analyses. At that time, final routes will be selected and environmental impact assessment studies prepared. Identify Study Segments Initially, eleven study segments were identified for evalu- ation based on locations of power generation sources and load centers (Figure 6-1). Later in the study effort as a result of discussion with utilities and agencies, four additional study segments were identified for evaluation. Locations of these 15 study segments in the context of Southeast Alaska are shown in Figure 6-1. The fifteen study segments are numbered and titled as follows: Segment 1. Skagway to Whitehorse Segment 2. Skagway - Haines-Juneau Segment 3. Juneau to Green's Creek Segment 4. (Hawk Inlet to Hoonah, included in Segment 14) Segment 5. Snettisham to Kake Segment 6. Petersburg to Kake Segment 7. Kake to Sitka Segment 8. Tyee Lake to Swan Lake Segment 9. Ketchikan to Prince of Wales Island Segment 10. Swan Lake to Quartz Hill Segment 11. Quartz Hill to British Columbia Segment 12. Ketchikan to Metlakatla Segment 13. Tyee Lake to Ketchikan/Thorne Bay Via Cleveland Peninsula Segment 14. Hawk Inlet to Hoonah to Sitka Segment 15. Quartz Hill to Prince Rupert Transmission line routes identified for each of these seg- ments are discussed later in this chapter. Route Selection Objectives The transmission line route selection process was guided by the goal of identifying an environmentally and technically acceptable route which provides reliable electric service to communities at reasonable cost. Specific objectives which were identified included the following: e Parallel existing transmission lines and roads, when possible, rather than open new corridors. 7 Avoid routes parallel to streams. e Avoid prime or important recreation areas. e Minimize impacts to visually sensitive areas. e Minimize routing through private land holdings. 6-2 FIGURE 6-1 WHITEHORSE Sse 4 SKAGWAY HAINES HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG LOAD CENTERS PRINCE 2 LEGEND: OF WALES 13. e ISLAND O GENERATION SOURCES mes - EXISTING T/LINE QUARTZ PROPOSED T/LINE HILL METLAKATLA S of / ° PRINCE RUPERT (_ il eaanee ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY SEGMENT DESIGNATIONS HARZA ENGINEERING COMPANY . OCTOSES 1SE7 e Avoid routing above elevations of 1500 feet. e Minimize routing through wetlands and on steep slopes. e Avoid sensitive biological and cultural resource areas. These objectives helped determine the evaluation criteria which were used to evaluate and compare the route alternatives. Evaluation Criteria Based on the project objectives identified for the study and the study team's experience and knowledge of conditions in Southeast Alaska, several evaluation criteria, or factors, were established. These were inventoried to allow comparison of the technical, environmental and economic merits of each route. The evaluation factors and their units of measure are shown on Table 6-1. Evaluation factors were grouped into four principle evaluation categories: physical constraints, biological constraints, social/cultural constraints and costs. Following is a brief discussion of each category. Physical Constraints. The physical constraint evaluation factors used for comparing the routes give an indication of the technical acceptability of a route in terms of reliability, risk, ease of construction and maintenance. For example, a well designed and properly installed submarine cable may be quite reliable as defined in terms of outages on an annual basis, but its risk factor is still high since an outage, when it does occur, is often difficult to repair, time consuming and costly. Similarly, transmission lines can be constructed on steep slopes and high elevations, but in general, such locations experience more frequent outages and are more difficult to construct and maintain than lines located on flatter slopes and at lower elevations. Five physical constraint evaluation factors were used to compare route alternatives. These were: Major stream crossings. Steep slopes. Elevation. Access. Muskeg/wetland areas. Route alternatives were placed on 1:63,360 scale topo- graphic maps and then each evaluation factor was inventoried in terms of miles routed through or number of times crossed as shown in Table 6-1. Access, or roadless areas were inventoried 6-3 Table 6-1 EVALUATION FACTORS FOR ROUTE COMPARISON Length Unit* Cable mi Overland mi Physical Constraints Major Stream Crossing # Avalanche/Steep Slope Areas mi Elevation: 500-1500 feet mi 1500 feet mi Exposure: Ridge Top Crossing mi Access: Roadless Areas mi Muskeg/Wetland Areas mi Biological Constraints Anadromous Streams Crossed # Anadromous Streams Paralleled mi Shellfish Harvest/Spawning Areas # Waterfowl Use Areas mi Eagle Nest/Concentration Areas # Social/Cultural Constraints Land Use: Wilderness Areas mi USFS LUD2/LUD3 mi/mi Airports (within 1 mile) # Designated Refuges/Parks # Visual Impact: Ferry Routes mi Trails/Cabins #/# Other areas mi Cultural Resources: Existing Sites # Potential Sits Land Status: Federal/State mi Community/Borough mi Private mi Table 6-1 (cont'd) EVALUATION FACTORS FOR ROUTE COMPARISON Costs Cable: DC AC Overhead: Base St. Slope/Rock Muskeg /Wetland Additional Costs (add above) Row Clearing Helicopter Constr. Terminals: AC Terminal DC Converter Station Contingencies Engineering, Administration, Construction Management and Land Acquisition from USFS transportation sytem maps obtained from district Forest Service offices. Roads designated as planned by the Forest Service were counted as existing, along with existing logging roads. Muskeg/wetland areas were generalized from topo- graphic maps, except for information received from agencies and previous studies since the extensive area covered for this study did not allow time or budget for detailed investigations or field reconnaissance. Biological Constraints. Biological resource factors used for comparing the routes relate to the need to avoid sensitive environmental resources. Six biological constraint factors were used for this evaluation. These included: Anadromous streams crossed. Anadromous streams paralleled. Shellfish harvest/spawning areas. Waterfowl use areas. Eagle nest sites. Muskeg/wetland areas. Transmission line impacts to fish and shellfish are most likely to occur from sedimentation due to erosion or submarine cable installation. In general, most of these impacts are negligible if proper construction techniques and erosion control measures are used. Minimizing clearing near stream crossings and keeping parallel lines at least 300 feet away from streams, where geographical constraints allow, will help minimize or avoid such impacts. Turbidity resulting from cable burial is expected to be localized and rapidly dissipated by tidal action. Similarly, any habitat disturbance is expected to be returned to pre- project conditions due to tidal action soon after cable con- struction activities are completed. Long term impacts may result from cable spans interfering with bottom fishing activi- ties, particularly where submerged cables span underwater pinnacles. Areas of noted commercial fishing activity should be avoided as much as possible. Many of the inlets and bays in Southeast Alaska receive high concentrations of waterfowl or are important travel cor- ridors for migratory waterfowl. Transmission line routes through these areas can increase the potential for waterfowl mortalities as a result of collisions with conductors, especial- ly for lines routed close to mouths of anadromous streams where eagles and waterfowl tend to concentrate. Studies have shown that most collisions that do occur, occur with the small over- head shield wires, rather than the large more visible conduc- tors. Such shield wires are not likely to be needed because of 6-4 the low insidence of lightening in Southeast Alaska. While this may be true in most cases, Alaska Department of Fish and Game personnel have noted that waterfowl collisions are still of concern due to the frequently foggy conditions in Southeast Alaska coupled with typical early morning and late evening waterfowl movements. Eagle nest sites were inventoried from U.S. Fish Wildlife Service survey maps. While sensitivity is high due to their regulatroy status, actual impacts of the line on eagles is expected to be low. Electrocution of eagles is not anticipated to be a concern as the conductors will be sufficiently far apart from each other and from grounded objects to eliminate simulta- neous contact and electrocution. Similarly, collisions of eagles with the conductors is expected to be rare. Locating lines near the mouths of anadromous streams where eagles are concentrating on spawning salmon, however, should be avoided. Many transmission line impacts on eagles can be avoided by keeping lines at least 1/16 mile away from nest sites and by timing construction to avoid sensitive nesting times. Muskeg/wetland areas were considered for biological reasons as well as for engineering constraint reasons. Such habitat provides important feeding and nesting habitat for waterfowl such as trumpeter swan and geese and also provide important habitat for deer, bear, moose and other terrestrial and avian species. Other evaluation factors noted in agency comments but not inventoried at this time include mountain goat habitat, old growth forest and other habitats associated with big game such as deer, moose and bear. These factors, as well as those listed above, should be inventoried in detail as necessary to support environmental impact and route refinement studies for those transmission lines segments which proceed toward implementation. These future environmental studies will require close coordina- tion with state and federal agencies. Social/Cutlural Constraints. Social and cultural con- straint factors relate to resources in which a transmission line's presence affects the value placed on that resource by people, and resources which are of concern due to regulatory requirements and personal safety reasons. Recreational and visually sensitive areas are examples of the first category; cultural resource sites and wilderness areas are examples of the latter category. Four social/cultural resource evaluation factors were iden- tified for this study. These were: Land use Visual impacts Cultural resource sites Land status As shown in Table 6-1, several of these factors included subfactors. Land use constraints were considered in terms of selecting a route which would minimize impacts on designated parks, refuges and wilderness areas, avoid conflicts with airports, and maintain compatibility with forest service land management objectives. As multiple use forest management is the principal land use for much of Southeast Alaska, Forest Service Land Use Designations (LUD) which were considered to be less compatible with the presence of a transmission line were noted. These included LUD categories I, II and III. Management objectives for these three LUD's are summarized as follows: LUD I. An area allocated to LUD I would be recommended for wilderness designation or be studied for such a designation. LUD I is applied to undeveloped lands which provide opportunities for solitude - and primitive types of recreation and contain unaltered habitats for plant and animal species. The LUD I areas were included in the evaluation under wilderness areas. LUD II. This designation provides greater management flexibility while retaining the primitive envi- ronment. Specifically, power developments are permitted with the condition that they retain the overall primitive characteristics of the allo- cated area. Roads can be built to serve the maintenance of a power development. LUD III. Areas allocated to LUD III are managed to provide a balance between amenity and commodity values. The management goal is to achieve a high degree of compatibility between competing resources in the same area, and timber harvesting is a permit- ted activity. This designation does not restrict transmission line development. LUD IV. This designation provides for intensive develop- ment of resources with emphasis on commodity resources. This designation is not considered a constraint to transmission line routing and thus, not noted. 6-6 Visual quality is an important managed resource in South- east Alaska and an important route evaluation factor in this study. Thousands of visitors annually travel Southeast's inland passage on the State's Alaska Marine Ferry System. Many other visitors and locals travel the thousand of miles of waterways and inlets in search of recreational experiences. Because the impacts of a transmission line on recreation resources would be primarily visual, emphasis has been placed on noting State Ferry routes, and trails, cabins and campgrounds in proximity to transmission line routes. Since transmission facility prominence declines readily at distance beyond 2-1/2 to 3 miles, these factors were inventoried for the routes only if they were within three miles of the identified route. An additional evaluation factor, additional use areas, was included and subjectively inventoried to reflect potential visual impacts on popular areas such as lakes, inlets and resi- dential areas. Visual impact constraints were inventoried noting route locations in relation to identified Ferry routes and Forest Service cabins, campgrounds, and trails identified from topo- graphic maps and by resource agencies. Time did not permit a detailed inventory of all existing trails and cabin sites or inventory and evaluation of the Forest Service's visual resource Management objectives inventories. Cultural resource sites were noted for the route selection study because of their regulatory and permitting importance. Existing and potential sites were inventoried in the vicinity of each transmission line rate for each segment (Appendix C). Generally, most cultural resource sites can be avoided through proper siting of the transmission line route in final design. As such, they are not as significant as some of the other resource factors in determining a preferred route. However, noting their presence does give on indication of the extent of potential field investigation work one route may require com- pared to another. Land status was used as an evaluation factor because cer- tain types of ownership, such as native and private, generally present more restrictions and higher acquisition costs that others. In addition, private and native land owners often object to transmission lines on their property because they may limit future development and use. Land ownership classifica- tions used to evaluate and compare potential routes included: e Federal/state ownership . Local government (City/borough) ownership e Private/private selected ownership 6-7 The number of miles of transmission line crossing each land ownership classification was inventoried for each alternative route. Land status information was obtained from the Alaska Department of Natural Resources and the US Forest Service (regional office, Juneau). Costs. Costs for the overhead routes were noted in terms of material and construction costs per mile. Maintenance costs were not included in the route selection study. Submarine cable costs, were given lump sum prices since the pricing varied according to the line's length and logistical requirements. Line termination costs including substation and/or DC converter station costs were also considered. Finally, a contingency allowance and an estimated cost for engineering, construction management, land acquisition and owners administration was added. For overhead lines unit per mile costs were developed based on different construction requirements. For example, route lengths through muskeg/weltand areas received a higher cost per mile than a route on stable soils. Cable costs included lump sum figures for each route. Overhead transmission line costs were subdivided into three categories which included a base construction cost per mile, per mile cost for construction on steep slopes with rock founda- tions, and per mile costs for construction in muskeg/wetland areas. The assumption for the overhead base construction cost was line construction on good soils with adjacent road access. Unit costs were applied using information inventoried for the physical constraint factors. Since for this study, such information was inferred primarily from topographic maps, it is important to keep in mind that costs are generalized and devel- oped in the absence of information obtained from detailed field studies. Additional costs included unit costs for right-of-way clearing and helicopter construction. Since detailed vegetation inventories were not conducted for this study, right-of-way clearing was assumed for all overhead route lengths. This is expected to raise the costs for some routes but it is not anti- cipated to significantly change the route selection. Helicopter construction costs were added to the overhead costs for all unroaded areas. It was assumed that roads would not be constructed in unroaded locations. Terminal costs were included for DC converter stations, AC substations and upgrades of existing substations. 6-8 Alternative Route Identification For this study, the term route is synonimous with corridor. The route may be fairly well defined in some locations where it parallels existing transmission lines or existing roads. In other areas, less well-defined by available data or physio- graphic constraints, the width of the route as represented by the lines shown in the figures may vary considerably (1/4 to 3 miles). Initial route alternatives were identified by noting begin- ing and end points established earlier and then identifying technically acceptable routes from topographic maps, USFS maps, and utility system maps to connect them. When possible, alter- natives were identified that paralleled existing or planned Forest Service roads and existing transmission lines. In some segments, route locations were well defined due to existing road systems and/or physical constraints. In these cases, only one route was identified. Also, some alternatives were modified and new alternatives added as a result of discus- sions with Agencies. These Agency suggested refinements have been noted on the route alternative maps shown for each segment. Data Collection and Agency Consultation Once route alternatives were identified, data collection efforts were initiated. Topographic maps, USFS transportation system maps, and high altitude photography were obtained and reviewed. Relevant information from previous utility system reports as well as other reports from state and local govern- ments were also reviewed. A list of the reports and documents reviewed is noted in the bibliography at the end of this report. In general, information to support most of the physical constraint evaluation factors was obtained from topographic quadrangle maps. Time constraints and the extensive area to be covered did not allow for detailed inventory of evaluation factors. As a result, some resource factors, such as wetland potential, may be under inventoried, while others, such as steep slope may be over inventoried. As the inventory process was consistant for all segments, the information collected for these evaluation factors is considered valid for making alternative route comparisons within the scope of this study. Detailed feasibility analysis of each transmission line segment, prior to its implementation, should include a more thorough investigation of environmental impacts than the constraints of this study has allowed. The access evaluation factor (road vs. roadless) was inven- toried from USFS transportation maps, and from discussions with Forest Service personnel. In addition to existing logging roads, planned logging roads were also noted and considered as roaded areas, since such roads are likely to be constructed well within the construction time-frame of the transmission lines. Biological constraint factors were inventoried from Alaska Department of Fish and Game Habitat Management maps. Eagle nest sites were inventoried from eagle survey maps obtained from the U.S. FIsh & Wildlife Service. Visual and land use constraint factors were inventoried from various maps, reports, and agency comments. Cultural resource sites were inventoried by a cultural resource subcon- tractor (see Appendix C). An essential part of the data collection and evaluation effort was Agency Consultation. Topographic maps with marked route alternatives for each segment were sent to various Federal, State, and Local Agencies for their review and com- ments. This was followed up by meetings in which routes and issues were discussed. During the meetings, forms were passed out containing segment lines and technical and environmental resource criteria. Agencies were asked to note on these forms their perception of the degree of impact various segment links may have on various resource categories, as well as suggestions for refinements or additional alternatives. In June 1987 the Power Authority circulated the draft of this report requesting comments from the contacted agencies. Information received from these agency contacts was factored into the comparison of alter- natives discussed later. Agencies contacted during the project study effort included: Federal Alaska Power Administration Corps of Engineers Environmental Protection Agency Federal Aviation Administration Fish and Wildlife Service Forest Service National Marine Fisheries Service National Park Service U.S. Coast Guard 6-10 State Department of Environmental Conservation Department of Fish and Game Department of Natural Resources Department of Transportation and Public Facilities Department of Governmental Coordination Local City of Haines City and Borough of Juneau City of Ketchikan City of Petersburg City and Borough of Sitka City of Skagway City of Thorne Bay City of Wrangell Ketchikan Gateway Borough Documentation of Agency Consultation is included in Appendix D. Private entities contacted are listed in Chapter 1. Alternative Comparison and Selection Information gathered from sources was noted in constraint and cost inventory forms by individual segment link for each evaluation factor for each study segment. Information was inventoried by individual segment links since several links comprise one alternative, and some links are included in more than one alternative. For the alternative comparison, individual segment links and their resulting technical, environmental and economic information were combined to indicate the different route alter- natives identified for each study segment. For example, segment links 6.2, 6.7, 6.9 were combined to form one alternative. These alternatives were documented in tables titled Alternative Comparison Summaries. It is important to keep in mind that for some study segments, evaluation factor information was not available or was not complete. The segment summary matrices note such occur- rences by marking that factor with an asterisk or leaving the space blank. These summaries formed the basis for selecting a preferred route for each study segment. To the extent that data was sufficient, engineering, environmental and economic route preferences were noted for each study segment. A final route 6-11 preference, combining the above three preferences was selected for each study segment when that selection was clear. When conflicts among the engineering, environmental and economic preferences existed, trade-offs were noted in the text discus- sion and final selections made based on judgement of the study team with respect to line reliability, reasonableness of cost, and environmental acceptability. Final preference selections also considered agency comments and previous studies by others. The following discussions detail the results of the route comparison and selection for each study segment. Each segment discussion is supported by a route alternatives map(s) (Figures 6-2 through 6-15), and/or an alternative comparison summary table. These are followed by Figure 6-16 which gives the lengths of the various selected routes. 6-12 SEGMENT 1.0 SKAGWAY TO WHITERHORSE Description of Alternatives Initially, several segment links were identified for con- necting and routing the Canadian power surplus available from Whitehorse, into Skagway as shown in Figure 6-2. After review of the links by Agencies and the community of Skagway, some links were eliminated and a additional link (1.2A) was added. Segment link 1.6 which followed the railroad into Canada was within the Klondike Gold Rush National Park. Such a route would require a lengthy and difficult permitting process under the National Historical Preservation Act. Segment 1.6 would also present serious impacts to cultural resource sites, have extreme avalanche potential, heavy winter snows and icing conditions. For those reasons segment link 1.6 was eliminated from further screening. Similarly, after review and discussion with Agencies, segment link 1.3 which routed on the steep slope east of Skagway, was eliminated. This link would present significant visual, impacts to viewers coming into Skagway via the White- horse to Skagway Highway. In addition the route would be very difficult to construct and maintain on the steep slopes. An additional link was added (link 1.2A) based on sug- gestions from Agencies (see Appendix D for documentation of Agency consultation). This suggested realignment parallels the railroad corridor, crosses the Skagway River and then stays low on the west slope before it crosses the highway. Alternative Comparison As a result of the above information, two route alterna- tives were identified for further comparison. Except for segment links 1.2 and 1.2A, both alternatives are identical and parallel the existing road corridors into Canada. Alternative route A parallels the existing road corridor for the entire distance. Alternative route B follows part of the Agency sug- gested refinement and drops away from the highway for about two miles. Table 6-2 presents the summarized information for each of the alternatives. Route Length. Alternative B is the shorter of the two routes, but only by about 0.2 miles. No cable crossings are required for either route. 6.1-1 Physical Constraints. Based on the physical constraints inventoried, route B appears preferable, though not by a signi- ficant amount. Alternative B's longer length at lower eleva- tions avoids roughly one mile of steep slope construction compared to alternative A, as well as about 1.2 additional miles of construction at elevations between 500 and 1500 feet. While alternative B has 1.4 miles of roadless area to construct com- pared to alternative A, the amount is not great and its location is such that construction workers may be able to access most of the length by vehicles from each end rather than use helicopter construction. Both alternatives will route adjacent to the railroad corridor coming out of Skagway and cross the Skagway River near the existing highway bridge. The alternatives were the same for the other physical constraint factors inventoried. Either of the two alternatives are expected to experience outages due to avalanche, winds and icing problems which are likely to occur as the line gets above tree-line and elevation 1500 in segment 1.5. No alternatives exist, other than burial of the line, to avoid these conditions. Biological and Social/Cultural Constraints. Few differ- ences were identified between alternatives for the constraint factors inventoried. Alternative B is expected to create less visual impact due to its route location in segment link 1.2A. In this location; the line is expected to be largely screened from view by motorists on the highway because of the line's lower elevation and the intervening topography and vegetation. While Alternative B-may be slightly preferred with respect to reducing visual impacts, both routes will create significant visual impacts on the historic Skagway setting and from the existing road corridor. In addition to the visual impact concern, other environ- mentally sensitive areas, common to both alternatives, include routing through approximately one mile of the Klondike Gold Rush National Park, potential impacts to historic trails and sites in and around Skagway, and potential impacts to areas used by mountain goats. Impacts to mountain goats is expected to be minimal if the route stays close to the existing road corridor. Physical impacts to cultural resource sites are expected to be avoided, but visual impacts to such sites will remain. 6.1-2 Any routing of a transmission line through a unit of the National Park System would require application for a right-of- way permit from the National Park Service. Such an application would be processed in accordance with existing federal regula- tions, (43 CFR 36 and 36 CFR 14). In addition, in determining whether to approve an application for an electrical transmission line in Klondike Gold Rush National Historical Park, the Nation- al Park Service is required to assess whether there are any economically feasible and prudent alternative routes to the proposed route. As a result, on EIS would likely be required and prepared by the Park Service. Feasible alternatives to this section of line route may be to route the line around the Park Boundary, or to bury the por- tion of the line passing through the park adjacent to the road. Costs. Total estimated costs for the alternatives were very close, with alternative B being slightly less costly than alternative A, by a total of less than $70,000. The difference in cost might be more if the unroaded section of alternative B could be constructed without the need of helicopters, but that difference would still be less than $100,000. As a result, economically, either route could be consid- ered, even though Table 6-2 reflects the slight advantage of Alternative route B. Selected Alternative Based on the evaluation and comparison of the information collected, alternative route B is indicated as the preferred alternative for economic analysis. Regardless of the route finally selected, serious study must be placed on reducing visual impacts in the Skagway vicin- ity and to historical resources, and on reducing the route's impact on the Klondike Gold Rush National Park. Either route shown in Figure 6-2, can be expected to meet with much opposi- tion and require lengthy permitting procedures. 6.1-3 LTERNATIVE COMPARISON SUMMARY INTERTIE SEGMENTS |seamenT “ O SK AG WA. VY - WH. IVE) Hoe. SL SEGMENT | a ALASKA INTERTIE Al ROUTE ALTERNATIVES 70 ra EVALUATION OMT TLL, TH) wae nee: SeGMENts . a a Seas F rwvscanconstaamrs 77 MULL LILLIAN LLLLLLLLLLLN LLL LLL WILLLLIMLLLLLL oo MAJOR STREAM CROSSING AVALANCHE/STEEP SLOPE AREAS z zs ELEVATION 500 1500 FEET Ss. a/ 1900 FEET 6.0 £.0 EXPOSURE RIDGE TOP CROSSING 40 WP ACCESS ROADLESS AREAS CO “4g MUSKEG/WE TLAND POTENTIAL Feoconea commune WZINVIID = == = = = VILL Noresicomments [ANADROMOUS STREAMS CROSSED t+—— # Fossible adergrednt7 or revere ANADROMOUS STREAMS PARALLELED — m 5 = opriets %A.0gh Or AtodN a SHELLFISH HARVEST/SPAWNING AREAS mi go = ZB 5 WATERFOWL USE AREAS ~ 2 Kendke ‘ se mee “7 ad EAGLE NEST SITES SS mame“ MEHL === —— = = WLLL, = LAND USE WILDERNESS AREAS. O USFS — LUD2/LUD3 el AIRPORTS (within | emute) DESIGNATED REFUGES a PARKS f. e VISUAL IMPACT FERRY ROUTES L / TRAILS/CABINS-CAMPGANDS 7Z¢ OTHER USE AREAS. (o 4 CULTURAL SITES. EXISTING/POTENTIAL LAND STATUS FEDERAL/STATE Ma . LOCAL Gov'T 8 PRIVATE/PRIVATE SELECTION mm a 3432 + Feta TET LLM LLLLRLLLL LLL CABLE OC Ac OverHeao ease _ _ ¥O_ ST. SLOPE/ROCK _ ENGINEERING PREFERENCE : MAB muskecowercano — 272 _sinu ENVIRONMENTAL PREFERENCE : AL 7 & ECONOMIC PREFERENCE [M278 ADDITIONAL COSTS ( add tc above) ROW CLEARING _ _ = Sim HELICOPTER CONSTR. 2 9_Sim TERMINALS: AC TERMINAL « OC CONVERTER STATION CONTINGENCIES ENG. ADMIN. CM. LAND rorat HARZA ENGINEERING CO. oct. 1987 ALTERNATIVE SELECTED FOR ECONOMIC ANALYSIS: 2-9 3J18VL LEGEND: © wom PREFERRED ome EX ISTING/ ROUTE PLANNED ROADSE om om ALTERNATIVE eeeee AGENCY ROUTES SUGGESTED sali ELIMINATED REFINEMENT FROM FURTHER ———— PARK SCREENING BOUNDARY woo EXISTING T/LINE 3 Se ot 3% : eee KLONDIKE GOLD RUSH ~ NATIONAL PARK ~ Stn eran ALASKA POWER AUTHORITY SOUTHEAST INTERTIE PROJECT SEGN 7 SKAGWAY — WHITEHORSE ROUTE ALTERNATIVES Ries SEGMENT 2.0 SKAGWAY-HAINES-JUNEAU Description of Alternatives The system studies described in Chapter 2 established 138 kV as the appropriate voltage for the Southeast Intertie System. As it pertains to the Skagway-Haines-Juneau interconnection, this means that the 138 kV inteconnection from the north must be completed, through Juneau, to the 138 kV bus at Thane substa- tion, the terminus of the transmission line from Snettisham. The evaluation and comparison of route alternatives from Skagway to Juneau (Thane) consisted of an examination of alternatives using direct current (DC lines) and more conventional alternat- ing current (AC lines). Because of the long distance covered, and the large number of potential alternatives, the evaluation was conducted in two parts. First, alternative overland routes between Bridget Cove and Juneau were evaluated and a preferred route selected (Figure 6-3a). Second, the preferred Bridget Cove to Juneau route was combined with alternative route seg- ments between Skagway and Bridget Cove (Figure 6-3). The resulting complete route alternatives were then compared and a preferred route selected. Because the length of required cable routes were in excess of 25 miles, DC as well as AC systems were compared. The DC alternatives continue overland from Bridget Cove to a converter station at Auke Bay as monopolar DC overhead lines. This is reflected only in the overhead line costs for those alternatives. The physical and environmental constraint factor information, as inventoried for this study was treated as the same for either type of overhead line. Bridget Cove to Juneau Three-overland alternatives, for either AC or DC transmis- sion lines, were identified for connecting the transmission sys- tem from Bridget Cove to the Juneau system (Figure 6-3a). Alternative A (segments 2.4, 2.7) exits Bridget Cove to the east for about a mile and then turns south into the South Fork and Boulder Creek drainages. It continues south crossing the Eagle and Herbert Rivers, past Wind Fall Lake and into the Montana Creek drainage before it connects to an existing sub- station at Auke Bay. From there it will parallel or require an upgrade of an existing AEL&P 69 kV line through Juneau to Thane substation. Alternative B (segments 2.3, 2.5, 2.7) follows the Glacier Highway south from Bridget Cove to Tee Harbor, (Figure 6-3a). At Tee Harbor the route turns southeast to follow a DOT proposed bypass which is located along the base of Auke Mountain. Alter- 6.2-1 native B continues along this route and terminates at the same location as alternative A. Alternative C (segments 2.3, 2.6, 2.7) follows the Glacier Highway as did alternative B. However, just north of Pearl Harbor (see Figure 6-3a) the route turns southeast into the Peterson Creek drainage, passes Peterson Lake to the east and then follows the Waydeleigh Creek drainage to the same sub- station location as the other two alternatives. Comparison of Alternatives Table 6-3 presents the evaluation factors for the three alternatives described above. Route Length. Between the three alternatives, route C is the shortest. At 36 miles, it is one mile shorter than alterna- tive A and 2.5 miles shorter than alternative B. Physical Constraints. Physical constraints are considered the least, overall, with alternative route B. Though, alterna- tive B has 3 more miles of steep slope than alternative A, alternative A has 18 miles of roadless area, compared to 0 miles for alternative B and 8 miles for alternative C. Alternative A's roadless condition could change as the Montana Creek drain- age has been proposed as a road corridor. Montana Creek's high recreation use however, makes this possibility seem remote. Alternative A is also less desireable than alternative B or C with respect to muskeg/wetland areas crossed. It crosses 3 miles more than alternative B and 1.5 miles more than alterna- tive C. Biological and Social/Cultural Constraints. Biological constraints inventoried favor alternatives A and C. Alternative A crosses one more anadromous stream than alternative C but parallels 8.5 miles of anadromous stream compared to one-half mile paralleled by alternatives B and C. With respect to poten- tial impacts on eagles, alternative A is clearly preferable, impacting no eagle nest sites compared to 13 for alternative C and 26 for alternative B. It should be stressed that the number of eagle nest sites inventoried was from general survey information. Specific nest locations relative to the transmission line routes are not known at this time. Even so, the information is still considered valid in terms of comparing the potential for impact. Biologically sensitive areas common to all the route alter- natives include crossings of the Eagle and Herbert Rivers. According to Alaska Department of Fish and Game representatives this area is an extensive wetland, high in fish and wildlife 6i52=—2 values. Other sensitive resource areas noted include wetlands in the Windfall Lake area and in the Montana Creek drainage. Alternative preference is more straightforward with respect to land use, visual and recreation resource constraints. Based on comments from resource agencies (See Appendix D), the alter- native with the least adverse impact to area visual and recrea- tional resources is the route paralleling the Glacier Highway (alternative B). While the Glacier Highway route potentially impacts views from State Ferrys travelling between Juneau, Haines and Skagway, such impacts are incremental to the visual impacts that present- ly exist due to development along the Highway including an existing 69 kV transmission line. Both alternatives A and C would present significant visual impacts to areas of high use and high recreational value in the Montana and Peterson Creek drainages. Sensitive recreational resources and facilities in those areas that are likely to be affected include Forest Ser- vice recreation cabins on Peterson Lake, Windfall Lake, and near Auke Nu Creek. Popular backcountry trails would be affected. These include the Windfall-Montana Creek Trail, Peterson Creek Trail, Herbert and Eagle River trails and the Spalding Creek Trail, In addition to these potential impacts, alternative C's location in the Waydeleigh Creek drainage is of concern because Waydeleigh Creek is a domestic water source fer the area as well as a designated andromous stream. Costs. Evaluation of estimated construction costs indicate that alternative B is the least costly of the three alternative routes. However, its total estimated cost is only $67,000 less than alternative C which is insignificant in comparison. Alter- native A was roughly $358,000 more costly than alternative B, largely because of the greater length of roadless areas requiring helicopter construction. Selected Alternative Based on the above comparison, the Glacier Highway route (alternative B) was selected as the preferred route segment between Bridget Cove and Juneau. In the course of the study, some Agencies suggested that the route between Bridget Cove and Juneau be routed underwater to Douglas Island. As an AC cable alternative to the Glacier Highway overland route, an underwater route would eliminate most of the potential environmental impacts noted earlier. However, the cost of constructing the cable route, which is roughly 25 miles in length, would be approximately $14 million, or over 6.2-3 ™ 2-1/2 times the estimated cost of the overland route. Concern for cable installation between Berners Bay (North of Bridget Cove) and Juneau has been voiced by National Marine Fisheries Service (NMFS) staff since this area is used for both spawning and over-wintering by Pacific herring. NMFS recommends that final alignment for an underwater cable installation be coordi- nated with various fishing organizations in order to avoid significant impacts. In the following discussion, the same underwater segment is evaluated as part of a total DC underwater cable system between Skagway and Juneau. Skagway-Haines-Juneau Four alternatives were identified for comparison. These included two underwater DC cable routes, and two overland AC transmission line routes. Description of Alternatives The two DC cable alternatives, alternative D and E enter Taiya Inlet at Skagway and route underwater to Haines (see Chapter 3 for detailed discussion on cables). At Haines, a DC converter station is constructed and a connection made to the existing transmission line system. Both alternatives then con- tinue underwater through Lynn Canal to Bridget Cove. At Bridget Cove alternative D comes ashore and follows the previously selected Bridget Cove to Thane route as an overhead DC line. Alternative E continues underwater to Douglas Island (segment 2.8, Figure 6-3a). The two AC overhead alternatives evaluated follow road corridors studied by the Alaska Department of Transportation and Public Facilities (DOTPF). These road corridors, Lynn Canal West and Lynn Canal East, were evaluated by DOTPF as part of an update to the Southeast Alaska Transportation Plan (Acres 1986). For this study, both routes were assumed to be roadless. The Lynn Canal West route (alternative G), shares the same route segment of the Lynn Canal East route from Skagway to a point directly east of Haines. At this point the route crosses Chilkoot Inlet with an AC cable, and routes past Haines to the Northwest before it crosses the Chilkat River and then follows the identified road corridor along the west shore of Lynn Canal. At St. James Bay (see Figure 6-3), the Lynn Canal West route crosses Lynn Canal with an AC underwater cable exiting at Bridget Cove. From Bridget Cove, the alternative follows the previously selected route from Bridget Cove through Juneau to Thane. 6.2-4 The Lynn Canal East route, (alternative F) follows the east shores of Taiya Inlet and Lynn Canal entirely overland to Bridget Cove (segment 2.1 A, 2.2A, Figure 6-3). This alterna- tive would connect Haines via an AC underwater cable crossing (segment 2.1B). As with alternative G, alternative F would follow the previously selected route between Bridget Cove and Thane. Comparison of Alternatives Table 6-3 summarizes the route comparison information for the four alternatives. Route Length. The shortest overall route length is alter- native D, at 103.2 miles. The longest route is alternative G at 115.3 miles. The alternative with the shortest amount of cable is alternative F. It has 2.8 miles of cable, compared to 92 and 67.2 miles of cable for alternatives D and E, respectively. Physical Constraints. Comparison of physical constraint factors among the four alternatives, clearly favor the under- water cable routes, alternatives D and E. Both the overland routes would be very difficult to con- struct and maintain because of the extent of steep slope, high avalanche potential throughout and major stream crossings encountered. Both overland alternatives would be constructed and maintained using helicopters. If a road is constructed according to plans of the State (DOTPF presently favors the east side route), then construction and maintenance would be much easier, but the line's reliability is still expected to be low with respect to outages from avalanches. As noted by personnel in the Alaska Division of Mining, Geological and Geophysical Surveys, an additional concern for all route alternatives is the risk of moderate to large magnitude earthquakes which this area has experienced (see Appendix D comments). While the cable alternatives may be more reliable in terms of reducing the frequency of outages, this advantage must be weighed against the fact that their risk factor is higher. It is much more costly and time consuming to repair a cable outage than an outage of an overhead line. In an area of noted earth- quake activity such as this, the location and installation of cables must be closely scrutinized, and compared with the ability of overland routes to be more easily repaired. Biological and Social/Cultural Constraints. Both under- water route alternatives are prefereable to the overland route alternatives with respect to minimizing potential impacts to biological, social and cultural resources. 6.2-5 Both overland routes would create significant visual impacts to travelers of the State's Marine Ferry system. In addition, both routes would require crossing the mouths of numerous streams which are typically concentration sites of eagles and other birds which feed on spawning salmon. Areas of particular environmental concern include the crossing of the Chilkat and Endicott Rivers for the Lynn Canal West alternative. The Forest Service has proposed a recreation cabin on the Endicott River. The Chilkat River area is nationally known for its concentration of eagles, and the com- munity of Haines receives thousands of tourists annually who come to view them. An overhead crossing of the Chilkat, in addition to creating potential impacts to eagles is likely to be strongly opposed because of its visual impact to the surrounding community. Eagle nest surveys conducted by the U.S. Fish and Wildlife Service indicate that close to 50 eagle nests are located in proximity to the Lynn Canal West route. Areas of particular environmental concern for the Lynn Canal East route include the Katzehin River crossing and the areas near the heads of Berners Bay and Echo Cove. The U.S. Forest Service has a recreation cabin located on the Katzehin River. The latter two areas are of particular concern because of extensive wetlands, anadromous streams and concentrations of eagles. Fish and wildlife eagle surveys were not complete for the east shore of Lynn Canal. In the completed surveys, 15 eagle nest sites were noted to be in proximity of the Lynn Canal East alternative. Costs. Comparison of the estimated costs shown in Table 6-3 indicate that alternative F (Lynn Canal East) is the most economical to construct. Its cost is roughly $25 million less than the other overland AC alternative (Lynn Canal West), and is about $14 million less than that of either of the DC cable alternatives. Selected Alternative The selected route for segment 2.0 and for the economic analysis is alternative F, the economically preferred route. This recommendation is based mostly on the conclusion that the costs of the cable route alternatives are too high to justify their selection over the land routes, particularly when considering that area earthquake activity increases the outage risk for cables. Though ADF&G and the USFS have noted prefer- ences for alternative E (all underwater), in the absence of having detailed engineering and environmental studies to support a preferred route selection, selection of the least cost alter- 6.2-6 native is appropriate for determining the feasibility of inter- tie connections, which is the principal purpose of this study. 6.2-7 Zo LTERNATIVE COMPARISON of SE ALASKA INTERTIE A SUMMARY EVALUATION FACTORS EVALUATION LENGTH UNIT CABLE AC/: 2c OVERLAND PHYSICAL CONSTRAINTS ENGINEERING PREFERENCE : MAE ENVIRONMENTAL PREFERENCE =: 047 & OrD as CAD 20\ LZ Q p ECONOMIC PREFERENCE : Al - Siem ale? MTILERNATIVES Ath hs 24,27 fe STEEP SLOPI € e ,e . aia Ea eee, a g Fe y E MRC. £5 26 2.7 EXPOSURE RIDGE TOP CROSSING MTA ZGZ ACCESS ROADLESS AREAS f , 42 A ra MIE: 24 aoe WUSELECTE D) 6 oO 3 MEI CELA ZEZ:7 Pease cnmanns WI MULL; Ml, Tah MIL ZN ANADROMOUS STREAMS CROSSED ¥ AAs KAG WAY - HAINES - SONA ANADROMOUS STREAMS PARALLELED =m fe a a3 2a SHELLFISH HARVEST/SPAWNING AREAS mi WATERFOWL USE AREAS mi 2 Mi dD: 24, 2 2 * MTB EAGLE NEST SITES Ze 3 ALI Ei 242.2, 2.8 (Dovacrs 1S.) a a Ee MATE: DUM 21E, 2 LA MLE 7a CEnsT Loa CAH) DESIGNATED REFUGES PARKS " , zi zd zr (WEST LY CANAL) TRAILS/CABINS CAMPGRNOS A y OTHER USE AREAS F i Y 94-6 LV CABLE CULTURAL SITES. EXISTING/POTENTIAL 8 Lp \Z / 9B KV CNGLES LAND STATUS FEDERAL/STATE m| 1572. ¥ oF Le ILA B/E, b ip 4G LOCAL Gov'T ™ 2. 5s as cy a ° 2 7 PRIVATE/PRIVATE SELECTION m p45 int Nope: Leute fon Bigger Gre CABLE OC = aoe oo ee 7 es OVERHEAD BASE = 6 8 st. store mock — 92 |/7B simi MUSKEG/ WETLAND 227 FE 1m, ROW CLEARING _ — HELICOPTER CONSTR 24.22 s1mi OC CONVERTER STATION ji ALTERNATIVE SELECTED CONTINGENCIES FOR ECONOMIC ANALYSIS Af Z ~ MAJOR STREAM CROSSING MIB: ZS 252.7 (SELECTED) >1500 FEET Me MLTELMATIVE S DCO ALTERNATIVE S F sera runasconsraanrs MIU TMILL Mn mide MILL to Me ALTERNATES berate nruces ALG: 204 218, 2284+ ATE Sea THI 7a a UM Zsatiaii Ind apoio he 7 TOTAL €-9 318VL 219 : SKAGWAY 2 LEGEND: Smee PREFERRED ome EXISTING/ ROUTE —o ome ALTERNATIVE *#e eo AGENCY ROUTES SUGGESTED Ht Ht ELIMINATED REFINEMENT FROM FURTHER —~~—= WILOERNESS SCREENING BOUNDARY women EXISTING T/LINE PLANNED ROADS FIGURE: 4 MILES SCALE 0 ALASKA POWER AUTHORITY EAST INTERTIE PROJECT SEGMENT 2 SKAGWAY -— HAINES — JUNEAU ROUTE ALTERNATIVES | re Tort | LEGEND: wm em PREFERRED omnes EX ISTING/ ROUTE PLANNED ROADSE- ewe ALTERNATIVE esse AGENCY He Ht Routes SUGGESTED ELIMINATED REFINEMENT FROM FURTHER —--—- WILDERNESS SCREENING ROUNDARY NG T/LINE ae ser SKISTH promamene su SCALE Q 4 MILES moniter SEAGWAY — HAINES — JUNEAU RGUTE ALTERNATIVES SEGMENT 3.0 JUNEAU TO GREEN'S CREEK Description of Alternatives Only one route was identified for the Juneau to Green's Creek Segment. This is shown in Figure 6-4. The steep slopes of the north shore of Admiralty Island, in addition to the Island's Wilderness Status limited route choices. In addition, the Green's Creek Mining Company, recently constructed a road to their mine site which reduces the clearing requirements for construction of a transmission line. As proposed, the transmission line route begins at the existing substation on Douglas Island and then follows the existing road system north and west along the shore to Middle Point. At this location, the line crosses Stephans Passage with 5.2 miles of underwater AC cable and exits at the north end of Young Bay near the head of Hawk Inlet. Here the route turns south and follows the Green's Creek road to the mine site. The total length of the route is 29.4 miles, including 5.2 miles of cable. With respect to physical constraints, the line will require roughly 10.7 miles of steep slope construction and construction in roadless area for about 2 miles. In general, construction is not expected to be difficult since the line will be constructed along existing road for most of its length. Areas of noted environmental resource concern in the vicin- ity of the route include the narrow strip of land between the head of Hawk Inlet and Young Bay. This location is bordered by waterfowl use areas on both sides, and has relatively high con- centrations of eagles because of the number of salmon streams in the area. Additionally, approximately 7.5 miles of the line routes through the portion of the Admiralty Island National Monument designated non-wilderness. While these lands are not subject to provisions and requirements of the National Wilderness Preserva- tion System, they are still managed to protect objects of envi- ronmental, cultural and scientific interest. The Forest Service has suggested that a buried cable alternative be evaluated: with- in the Monument lands to reduce visual impacts and vegetation clearing, since much of the area is windthrow prone and risks of major blowdown would be increased. 6.3-1 Costs Construction costs for the proposed transmission line route were estimated for three different operating alternatives, as shown in Table 6-4. One alternative assumed the proposed route to be a 34.5 kv spur to Green's Creek Mine and two others involve the segment at 69 kV and 138 kV, assuming the route continued to Hoonah as part of the West Route Intertie system discussed in Chapter 2. Total construction cost obviously favors the 34.5 kV system because of the lower material and installation costs. However, final selection of the voltage for this route will depend on the final intertie system selected. 6232 INTERTIE SEGMENTS ]ssomens 3O SINEAU-GEEENS ©. BEER | ALTERNATIVES Pesan ILL ALLL ea ee ct ae SEGMENT SE ALASKA INTERTIE Zz Oo ALTERNATIVE COMPARISON SUMMARY MAP REF.: SEGMENTS. }__| er 4 - ZS LY SVR 72 GV. KK, MT, B- CFLV SPE 722 ORME Moody , E7e. oe Mele - (3840 TEL E WEST RC7E SLEREEESE: NOTES/COMMENTS 1. We ACJERNWI WE FD07E S HELE COM SIDE LLP. 2. MTLENAIWES /NVES T1601 D PELT AN TO VPPLOPRITTE VOL TAG LEVEL DEPLNOING OV ASSOCUMTED SVSTEM PEP. Feta ————————5} ee 000 rN 7TH TNT THT ZZ MUSK EG/WETLANO POTENTIAL “e = ae en— == WEL COPTF <o Zo Zo AVALANCHE STEEP SLOPE AREAS Fwoxootastoninams IIL ohare —— == LAND USE WILDERNESS AREAS USFS LUD2/LUD3 erulems S. AIRPORTS (withon 1 muted + [] he DESIGNATED REFUGES! PARKS VISUAL IMPACT FERRY ROUTES | / TRAILS/CABINS -CAMPGRNOS [| OTHER USE AREAS “TS WoT IWVEN TO, ED CULTURAL SITES EXISTING/POTENTIAL #7#4 | LAND STATUS: FEDERAL/STATE om | \ Turareares e = grratana a eal a Fess tweens WALIIA ILIA ITN LL TILLY LTA LLL 4 LU heed weer owen A QsT PERMILE 4OR Ae OVERAHEXP eves, LV! Fk#-S CF f% BRE? 722 T25 E STS. heck: pas tS 178 MestkGfli /$5 65 42 CLENLING, 24 24 65 F 0cofmi CABLE »1500 FEET ANADROMOUS STREAMS PARALLELED =m SHELLFISH HARVEST/SPAWNING AREAS mi mR — a We, paca pa a= OLE KRon HES! SHEA AT OVERLAND EXPOSURE RIDGE TOP CROSSING WATERFOWL USE AREAS C LEGLIRES LPOGRTIDE (kN TAME ENGINEERING PREFERENCE tf Ps ENVIRONMENTAL PREFERENCE =: 427 4f ECONOMIC PREFERENCE : 47 AA ALTERNATIVE SELECTED 5 ae FOR ECONOMIC ANALYSIS . # DEPENDS ON SELECTED SYSTEM CABLE DC s ac s ovennean ease _ LAB/ES$im 5 ST. SLOPE/ROCK — __“%_ sim pees s ROW CLEARING _ _ _ on HELICOPTER CONSTR. — %_ _S/mi TERMINALS: AC TERMINAL OC CONVERTER STATION CONTINGENCIES ENG. ADMIN, CM, LAND we lewevee aS TOTAL MZle | /GBH6\ ZE7#S| v-9 FVL eve VEX tn eekeiibeune nw Boned GREENS CREEK MINE eS LEGEND: - SCALE 0 Seg WES wm mmm PREFERRED mem EXISTING/ : = pee PLANNED ROADS ALASKA PQWER AUTHORITY ALTERNATIVE ** 4.0% AGENCY : SOUTHEAST INTERTIE PROJECT —_— — ROUTES SUGGESTED : soe nue Ait ELIMINATED REFINEMENT = SEGMENT 3 FROM FURTHER —=-= WILDERNESS oD DOUGLAS ISLAND — GREENS CREEK SCREENING BOUNDARY ; ee — = q+ —— EXISTING T/LINE SEGMENT 5.0 SNETTISHAM TO KAKE Description of Alternatives Route alternatives to connect the Snettisham Hydroelectric project with Kake consisted of combining alternative segment links on each end of the line with an underwater DC cable in the middle (Figure 6-5). An all overland route was not considered to be practical because of the length involved, topographic constraints and the numerous underwater inlet crossings which would be required. Four alternatives were identified. Two alternatives (alternatives C and D) include a submarine cable from the Snettisham powerplant to Kake. The other two alternatives (alternatives A and B) would have a DC overhead line parallel the existing Snettisham to Juneau transmission line to Point Styleman before going via submarine cable to Kupreanof Island. On Kupreanof Island, two alternatives (B and D) follow the Gunnuk Creek drainage into Kake. The other alternatives (A and C), route to the west of the Gunnuk Creek drainage and then into Kake (Figure 6-5). Alternative Comparison Table 6-5 summarizes evaluation information for each alter- native. Route Length. Over 70 percent of the length of each route alternative is submarine cable. Alternatives A and B has 63 miles of cable, alternative C and D have 79.5 miles of cable. The shortest route overall is alternative A with a length of 89 miles. Physical Constraints. Comparison of the inventoried phys- ical Constraint information identified alternative C as the engineering preference. It has significantly less steep slope and roadless areas than either of the two alternatives which route overland to Point Styleman (alternatives A and B). In comparison to the other "all cable" route (alternative D), alternative C has slightly less roadless area and less length through muskeg/wetland area (Table 6-5). Biological and Social/Cultural Constraints. Comparison of evaluation factors for these categories indicated that alterna- tives A and C were prefereable with respect to biological con- straints. This was due to the fact that both alternatives avoid segment 5.6 which parallels Gunnuk Creek. In addition to 6.5-1 Gunnuk Creek being an important salmon stream, its watershed is the water supply source for the city of Kake (see Agency com- ments, Appendix D). All four alternatives potentially impact salmon spawning habitat and eagle concentration areas in the portion of segment 5.4 that crosses lower Schooner and Point White Creeks (see Figure 6-5). Available data indicates the route preference with respect to social/cultural constraints to be either of the two alterna- tives with longer cable lengths (alternatives C and D). These routes are preferred since potential cultural, visual and land use impacts would be minimized. Costs. Route alternative D is estimated as the least cost alternative at $57.96 million. Its cost is on the order of 500,000 less than those of alternatives A and B and approxi- mately equal to that of alternative C. Selected Alternative Considering the above information, alternative route C was selected as the preferred alternative for economic analysis. While it is not the least cost alternative, alternative C is preferable technically and environmentally. Future detailed studies of this route should focus on refining the route alignment to avoid sensitive salmon spawning streams near Kake. 6.5-2 wrenvie seaments |seament 5.0 SA/E7//SA/AM - KAKE SE ALASKA INTERTIE ALTERNATIVE COMPARISON SUMMARY SEGMENT fo ROUTE ALTERNATIVES VMN. OY GMOS Wau ape Soa 7) VLU, = THLE 7) MUSK EG/WE TLAND POTENTIAL oop | siorocicarconstaamts —_V/////, MUL MM (NLA LLIN LLL LLL S.6 FIND 6.7, SCLATMNE ANADROMOUS STREAMS CROSSED + ANADROMOUS STREAMS PARALLELED om iz; 3 ZZ #2 5 + ia SHELLFISH HARVEST/SPAWNING AREAS. mi WATERFOWL USE AREAS m Atal EAGLE NEST SITES COR é IVE 5.2 DSF. eames a ‘hu MUL TM TILL LLL, 8: 00h 8. OS Sie LAND USE WILDERNESS AREAS pe SAME BERIPOR. LIME TERMINATION COSTS SHON * Assure No Pkial. De -#ek&/7y AT LAKE AHP Ke Loe LO7~ FAILITIES ONLY, BOMM DE AmeCITIES PRIVATE/PRIVATE SELECTION mw Pamela pa LMI LLL LLL LALLLLLLD AIRPORTS (wither | uted CABLE OC ENGINEERING PREFERENCE Mee ENVIRONMENTAL PREFERENCE =: AZZ C ECONOMIC PREFERENCE :MTED ALTERNATIVE SELECTED FOR ECONOMIC ANALYSIS ‘MTA HARZA ENGINEERING CO. locr. 1987] EVALUATION FACTORS EVALUATION |/ LENGTH nT MAP REF.: SEGMENTS |} | “ra B/, 542257 7 7 8 S154 66, 5.7 MCs 5254. 35 27 MAJOR STREAM CHOSSING o AVALANCHE STEEP SLUPE AREAS ae of AMT D: BE 4 68, $7 ELEVATION 500 1500 FEET 4.7 $2 1500 FEET EXPOSURE RIDGE TOP CROSSING NOTES/COMMENTS 4. TEAVSHMISSION £/NE 15 (CC 4S DEO OVELAHEAD FOR 4£/VKS S./ PARKS VISUAL IMPACT FERRY ROUTES TRAILS/CABINS CAMPGRNDS OTHER USE AREAS CULTURAL SITES EXISTING/POTENTIAL LAND STATUS FEDERAL/STATE ™ LOCAL GOV'T ™ AC OVERHEAD BASE _ _ 7b Sim st. score noc — _ YZ _ sim MuskEGwe TLAND ZAP. _ sim ADDITIONAL COSTS ( add tw above) ROW CLEARING _ — AA Sim HELICOPTER ConsTA. 2 _s/mi TERMINALS: AC TERMINAL DC CONVERTER STATION CONTINGENCIES ENG, ADMIN., CM, LAND wnvonw wenaen s-9 3718VL DESIGNATED REFUGES/ TOTAL 3|ZB529 2650 \27 980|57927 sg LEGEND: =m mmm PREFERRED ROUTE ome ome ALTERNATIVE | He +H} ROUTES ELIMINATED FROM FURTHER SCREENING ——rmee EXISTING T/LINE SCALE 0 ed ALASKA BOWER AUTHORITY SOUTHEAST INTERTIE PROJECT ome EXISTING/ PLANNED ROADS eeeee AGENCY SUGGESTED REFINEMENT —-— WILDERNESS BOUNDARY ame SEGMENT SNETTISHAM — KAKE. SEGMENT 6.0 PETERSBURG-KAKE Description of Alternatives The proposed transmission line includes conventional over- head 3-phase 138 kV conductors on wood H-frame poles and AC cables for underwater crossings. Several route segments were identified to connect Peters- burg with Kake, as shown in Figure 6-6. Based on review of previous transmission line routing studies done for different voltages, several segments which routed through the Petersburg Creek Duncan Salt Chuck Wilderness Area were eliminated. It would take an act of Congress to allow ingress through the Wilderness Area, and since reasonable alternatives appear to exist which do not route through the Wilderness, those segments were eliminated. Two routes were identified for further comparison; a south- ern route (alternative B) and a northern route (alternative A). A portion of the southern route (segment link 6-1) was modified before final comparison in response to Agency concerns noted for that portion of segment link 6.1 (see Appendix D for details of Agency Comments). Both route alternatives were identified in previous studies. Alternative A. The northern route alternative begins at an existing Substation south of Petersburg at Blunt Point. It parallels an existing subtransmission line into Petersburg, crosses Wrangell Narrows via submarine cable and then routes northward along the wooded slope adjacent to Frederick Sound before it turns westward into the Twelve Mile Creek drainage. There it follows lowland areas adjacent to existing and planned logging roads, for the most part, to Kake. The total length of the northern alternative is 53.6 miles, including 0.6 miles of underwater cable. Alternative B. The southern route alternative begins at a new substation located approximately three miles south of Blunt Point. The line exits to the west, crosses the Wrangell Narrows via submarine cable and routes through an unnamed creek drainage paralleling existing logging roads to Duncan Canal. After- crossing Duncan Canal via underwater cable, the line follows relatively flat terrain northward to the pass which divides the Duncan Canal drainages to the east with those flowing west to Hamilton Creek. The route follows a previously recommended route in the area west of Duncan Canal to minimize routing through muskeg areas. The route from Duncan Canal to the pass is unroaded and there are no known plans for logging roads at 6.6-1 present. West of the pass the route parallels existing logging roads to Kake. The total length of the southern route alternative is 46.7 miles, including 1.7 miles of underwater cable. Alternative Comparison Table 6-6 presents information summarized from segment link inventories for each of the alternative routes. The following discussion summarizes the above findings by evaluation factor category. Route Length. The shortest route in terms of total length is the southern route (alterntive B). It is approximately 7 miles shorter than alterntive A. However, it has roughly 1.1 additional miles of underwater cable which substantially increases its cost. Physical Constraints. With respect to the physical con- straints inventoried, the southern route (alternative B) appears preferable from an engineering point of view. The southern route traverses no steep slope compared to 4 miles of steep slope for the northern route. It crosses slightly more muskeg/ wetland area than the north route (2 miles more). The southern route has fewer unroaded miles than the northern route (5.5. miles) therefore access is better and the need for helicopter construction is less. Though the southern route has 1.1 miles more submarine cable, and thus a greater risk factor in terms of cable outage, the cable's location compared to that of the northern route is considered more reliable. The northern alternative cable crosses the Wrangell Narrows in an area of active shipping. In addition to concern for periodic dredging which is done to main- tain the channel, concern is higher for this northern alterna- tive with respect the ship's anchors snagging the cable. Biological, Social/Cultural Constraints. As shown in Table 6-6, route preference with respect to environmental constraint factors is mixed. Generally, the northern route is preferable with respect to minimizing potential impacts to aquatic resources and waterfowl; the southern route is preferable with respect to minimizing land use and social resource impacts as well as impacts to eagle nest sites. 6.6-2 Environmentally sensitive areas associated with the north- ern route include the steep forested slope between Petersburg and Twelve Mile Creek, the area near Portage Creek and Goose Cove, and the Wrangell Narrows crossing. High concentrations of eagles nest sites exist in area between Petersburg and Twelve Mile Creek as well as several anadromous streams which would need to be crossed. This same area is also highly sensitive to viewers travelling the inside passage on the Alaska Marine Ferry. The area near Portage Creek and Goose Cove (Figure 6-6), according to U.S. Forest Service personnel, is part of a major waterfowl migration path which leads southwest into the Duncan Canal area. The area also has several anadromous streams which flow into Portage Bay. Concern would be particularly high for portions of the line route near the mouths of these streams as these locations are areas in which eagles and other birds are attracted to spawning salmon. The Wrangell Narrows crossing is environmentally sensitive because of migratory waterfowl and commercial crab and shrimp fisheries. Tide flats on the Kupreanof side of the Narrows are used extensively by feeding waterfowl and for recreational and subsistance purposes by residents (see Agency comments, Appendix D))s Areas of the southern route that are environmentally sensi- tive include the Wrangell Narrows, Duncan Canal area and the Hamilton and Big John Creek watersheds. As in the Petersburg Creek area, the Wrangell Narrows area receives large concentra- tions of migratory waterfowl and supports shellfish and shrimp fisheries. The Duncan Canal area is particularly sensitive with respect to waterfowl use. According to U.S. Forest Service comments, Duncan Canal is one of the major waterfowl concentra- tion areas in Southeast Alaska. It is also the location of a shrimp trawl fishery which provides as much as 80 percent of the total shrimp catch in Southeast Alaska (Appendix D). Big John and Hamilton Creeks are both major salmon streams and any trans- mission line crossing will be of concern due to sedimentation impacts and impacts to eagles. In summary and within the limits of this study, both routes present substantial potential for impacts to environmental resources. For purposes of presenting a preferred route for economic analysis in the next phase of this study, the southern route (alternatives B) was judged to be preferable due to its lower land use, eagle and visual resource impacts, and the greater reliability in its Wrangell Narrows crossing. Costs. The northern route (alternative A) is the preferred route economically even though it is longer. The principle reason for this is the underwater cable crossing of Duncan Canal required for the southern route. The southern route's higher cost also reflects the need to construct a new substation rather than upgrade an existing sub- station as is done for the northern route. The southern alternative could possibly be routed to the existing substation, thus saving the cost of a new substation. However, any savings are likely to be minimal due to the cost of constructing the additional line on steep slope and the need for mitigation measures to reduce visual impacts to users of the Marine Ferry system in the Wrangell Narrows. Estimated costs for the two routes are $23.6 million for the northern route and about $26.5 million for the southern route. Selected Alternative Based on evaluation and comparison of the factors sum- marized in Table 6-6, input received from Agencies and review of previous studies, the recommended alternative for economic analysis is Alternative B (southern route). The higher cost and potentially significant aquatic resource and waterfowl impacts of the southern route, however, necessitate that, before final design of this Intertie segment commences, detailed environmental comparisons of these two alternatives be made. 6.6-4 SEGMENT @.O KAKE - PETE LS BUkG SEGMENT sl SE ALASKA INTERTIE ALTERNATIVE COMPARISON ROUTE ALTERNATIVES SUMMARY a 7 hm 7 NLL Tm THT TR Fmovacen conan ZIM ce ES a= = ee ANADROMOUS STREAMS CROSSED ANADROMOUS STREAMS PARALLELED =m Zis A SHELLFISH HARVEST/SPAWNING AREAS mi PETERS BURG AUD SCEMARINE WATERFOWL USE AREAS 2, $ CALCE ChOsSWIGS OF WRANGELL EAGLE NEST SITES MARKO S ID DEVEAN CAN AE Fics Van LL = ais = = == a=3| SEGMENT Et FEGUES AMEN LAND USE WILDERNESS AREAS VICKY Tet THROG Wf PETERS ~ MAP REF.: SEGMENTS PO 4er a: 6.2,67, 69 Tf, Mee: G465 65.69 NOTES/COMMENTS =| SEGMENT 6.1 RE@UIRES A NEW 138 KV SUBSTATION 500TH OF USFS LUD2/LUD3 ait Evt6 AND A SOCMNE AE SOLE AIRPORTS (within 1 emule) CLOSSING OF WENGE, AAALL DS. DESIGNATED REFUGES PARKS VISUAL IMPACT FERRY ROUTES TRAILS/CABINS CAMPGRNDS OTHER USE AREAS CULTURAL SITES EXISTING/POTENTIAL LAND STATUS: FEDERAL/STATE LOCAL GOV'T ™ PRIVATE/PRIVATE SELECTION rm == === Ts [costs timsoooy _VLLZXLLLLLIN LLL LLL LLL LLL LLL LLL CABLE OC overneao ease — “4B _ sim st suore/nocx — 7% — sim ENGINEERING PREFERENCE : M278 musecwerians /ZE._ sim ENVIRONMENTAL PREFERENCE 9: 47,2 ADDITIONAL COSTS ( add to above) ECONOMIC PREFERENCE uaa A $ s s s $ now cueanine .... 29. sim S$ HELICOPTER CONSTR. 29. _smi s s s $ s TERMINALS: AC TERMINAL ALTERNATIVE SELECTED DC CONVERTER STATION FOR ECONOMIC ANALYSIS :MI OB CONTINGENCIES ENG. ADMIN, CM. LAND 23556 |2Z6, et Boe = - LEGEND wm me PREFERRED ROUTE om omens = ALTERNATIVE | Het | Routes etiminaten . _ FROM FURTHER SCREENING ALASRA POWER AUTHORITY “SOUTHEAST INTERTIE PROJECT i seneaenie SEGMENT: 6 PETERSBURG — KAKE ete cnek sith aninaooneianemee Se ROUTE ALTERNATIVES re HARES ENOINEERING COMPANY Gare OUT | ~~ aw aw ~©WILDERNESS BOUNDARY fe eamemniton ote ™ EXISTING T/LINE EXISTING/PLANNED ROADS # PETERSBURG CR-DUNCAN. SALT CHUCK © WILDERNESS) aunold SEGEMENT 7.0 KAKE TO SITKA Description of Alternatives Three route alternatives were identified for connecting Kake and Sitka. All three alternatives include a 35 mile long DC cable crossing from Kake to Warm Springs Bay (Figure 6-7). Blue Lake substation was selected as the termination for all three alternatives. The existing transmission line from Blue Lake into Sitka would be adequate to carry the forecast loads. From Warm Springs Bay alternative A follows segments 7.2 and 7.6 to the existing substation at Blue Lake. Alternatives B and C follow the north shore of Baranoff Lake and continue west- ward into the Baranoff River drainage. Alternative B then turns north (segment 7.4) and crosses a high elevation ridge before entering the Blue Lake watershed. Alternative C continues west- ward (segment 7.5), crosses a high elevation ridge and routes north of Medrejia Lake before turning north and paralleling an existing road along Silver Bay to the Blue Lake substation. The total lengths of the three routes are 55.1 miles for alternative A, 55.3 miles for alternative B and 55.4 miles for alternative C. Over half of each route's length is underwater cable 35.2 miles). Alternative Comparison Table 6-7 summarizes evaluation information for each alter- native. Route Length. Total lengths of the three alternatives are almost identical. Alternative A is the shortest route, but only by 0.2 and 0.3 miles compared to routes B and C, respectively. Cable lengths are the same for all three alternatives. Physical Constraints. Alternative C is the most favorable alternative with respect to engineering preference, as can be seen by the comparison of physical constraint factors in Table 6-7. Alternative A, though the shortest of the three routes, would present significant construction and maintenance problems. Over five miles of this alternative's length is above 1500 feet elevation. Much of that length is over 3500 feet elevation. Exposure to wind, snow and icing is expected to be severe because of its ridge top location and location between two glaciers in segment link 7.2. In comparison, alternative C has only one mile of line located above 1500 feet elevation. It also traverses roughly 3 miles less roadless area than either alternative A or B. 6.7-1 Biological and Social/Cultural Constraints. No clear envi- ronmental preference emerged from the evaluations and comparison of the environmental factors inventoried. All three alterna- tives would present visual and land use impacts to the communi- ties of Manleyville and Baranoff. Forest Service representa- tives have noted that residents of Manleyville expressed con- cerns over the visual impacts of a pipeline corridor and may have major objections to a transmission line corridor (see com- ment Appendix D). Alternative C has the potential to impact more anadromous streams as it nears Bear Cove and Silver Bay towards the Sitka termination. However, as the line will parallel an existing road and transmission line in this location, impacts are not expected to be significant. Alternatives A and B, while preferable with respect to biological constraints, are less preferred with respect to social and cultural constraints because of their greater poten- tial of impacting visual and recreation resources in the vicin- ity of Blue Lake. Both alternatives would be visible to hikers along the Beaver Lake trail and users of the campground located at the west end of Blue Lake. Blue Lake is also the water source for a pulp mill and the City and Borough of Sitka. Costs. Total costs for the three alternatives range between $34.23 million for alternatives A and C and $34.28 million for alternative B. Though the estimated construction costs for all three alternatives are very close, alternative C was selected as preferred because more of its length is accessible by road in addition to being routed at lower elevations. Both factors will reduce maintenance-related costs in the long run. Selected Alternative Alternative C is recommended as the alternative for econom- ic analysis. Technically, it is the best route and would be the least costly to build. It should be noted that the City and Borough of Sitka have expressed a desire to have a line routed into the city from the north in order to increase the reliability of their transmission system as opposed to utilizing the existing Blue Lake/Green Lake transmission line. Such a route coming from the Manleyville or Takatz Lake region would be technically difficult and costly to construct, since it would require construction at high eleva- tions and crossings of exposed mountain passes into the Indian River drainage. For purposes of this study, the least costly and more reli- able alternative was chosen for determining the economic viabil- 6.7-2 ity of this segment as part of the Intertie System. Future studies of this segment should include more detailed considera- tion of the city's preferred alternative. 6.7-3 seament ZO KAKE-S/7KA secment| SE ALASKA INTERTIE Yo ALTERNATIVE COMPARISON ROUTE ALTERNATIVES : SUMMARY [venom LL UU NE ine eee cane 7 mae 6: seoments CABLE as CuGeO OVERLAND cs PHYSICAL CONSTRAINTS redhat hit TNT —— i Pe aie TNT 7 7 Z a i MAJOR STREAM CROSSING AVALANCHE STEEP SLOPE AREAS 7 A be ELEVATION 500 ISOOFEET BS a )1500 FEET hs EXPOSURE RIDGE TOP CROSSING ACCESS ROADLESS AREAS SEF | Be MUSKEG/WE TLAND POTENTIAL Be ata 24 ae THOS V/LLLL. = = eres LLL: —— NOTES/COMMENTS ANADROMOUS STREAMS CROSSED ANADROMOUS STREAMS PARALLELED =m SHELLFISH HARVEST/SPAWNING AREAS mi Zé WATERFOWL USE AREAS EAGLE NEST SITES INFO = = AHL SES HE I TANO USE WILDERNESS AREAS Oo USFS LUD2/LUD3 , AIRPORTS (withon I wie) DESIGNATED REFUGES’ PARKS " C VISUAL IMPACT FERRY ROUTES " Z, TRAILS/CABINS CAMPGRNDS y MN OMPLETE ) OTHER USE AREAS 7 = CULTURAL SITES: EXISTING/POTENTIAL LAND STATUS FEDERAL/STATE ~ G. na LOCAL Gov'T ™ PRIVATE/PRIVATE SELECTION mm VIVWM| SCA LTE S| THU LLM LLL. TINIL LLLLLLLIMLLLLL LL CABLE DC AC OVERHEAD BASE _ _ 7 _ " oO é st svopenock — — FZ _ sim ENGINEERING PREFERENCE [UTC MuSKEG WETLAND — 772. _ sim o ENVIRONMENTAL PREFERENCE =: 4/0A/C ADDITIONAL COSTS ( add 10 above) ECONOMIC PREFERENCE :MOME ROW CLEARING Osim Z Z HELICOPTER CONSTR. _/7__sim A TERMINALS: AC TERMINAL * oy ALE ALTERNATIVE SELECTED commence oe A TAAKE AISNE D Wd VE J FOR ECONOMIC ANALYSIS :Me7e ENG. ADMIN, CM.. LAND TOTAL t t HARZA ENGINEERING CO. 2-9 318VL TO KAKE \ LEGEND: SCALE 0 4 MILES Se mmm PREFERRED oes EX ISTING/ ——— ROUTE PLANNED ROADS ALASKA POWER AUTHORIT? ALTERNATIVE e@eeee AGENCY SOUTHEAST INTERTIE PROJECT ROUTES SUGGESTED ELIMINATED REFINEMENT SEGMENT 7 FROM FURTHER —=--—— WILDERNESS KAKE — SITKA SCREENING BOUNDARY : —-— EXISTING T/LINE j ROUTE ALTERNATIVES HARZA ENGIN SEGMENT 8.0 TYEE LAKE-SWAN LAKE Description of Alternatives Four alternative routes which combined various segment links were identified for comparison (Table 6-8). These alter- natives were identified after the elimination of several other segment links which routed through the Misty Fiords National Monument. An additional segment link (8.6) was identified by the U.S. Forest Service and incorporated into the alternative comparisons. All the route alternatives parallel the existing Tyee Lake and Wrangell transmission line, then turn south through the Eagle River drainage before crossing Bell Arm and Behm Canal. Alternatives A and C remain to the east of Eagle River and Eagle Lake, avoid crossing Bell Arm, and cross Behm Canal at Pt. Lees (see Figure 6-8). In the same area, alternatives B and D cross Eagle River and traverse the west slope. They then cross Bell Arm with an overhead cable, cross Bell Island overhead, and then Behm Canal via underwater cable. From a point south of Behm Canal, all four alternatives share the same segment link (8.4) through the Beaver and Klam Creek drainages. West of these drainages, topographic con- straints were considered too severe for routing; and routing east of the drainages would place routes in the Misty Fiords National Monument. From segment link 8.4, alternatives A and B turn eastward and follow existing and planned Forest Service logging roads north of Orchard Lake. Both then cross Orchard Creek and follow existing and planned roads to Swan Lake. Alternatives C and D turn south from segment link 8.4, cross Shrimp Bay with an overhead line and then follow along the shore of the head of Neet's Bay. Near the Neets Bay Hatchery, both alternatives turn east following an existing logging road until they turn to the southeast, crossing over a pass and intersecting with the other alternatives to continue south along Carrol Inlet and to Swan Lake. Alternative Comparison Table 6-8 summarizes evaluation information for each alter- native and indicates the segment links for each route. 6.8-1 Route Length. Total lengths of alternatives A, B, C and D are 50.2, 50.5, 51.4 and 51.7 miles respectively. The shortest route is alternative A in terms of total miles. However, with respect to underwater cable lengths, alternative A has 1.3 miles more cable length than either alternative B or alternative D. Physical Constraints. As shown in Table 6-8, alternative A is the preferred route with respect to engineering preference, Alternative C is next in preference. Both routes avoid the aerial crossing of Bell Arm which would require special founda- tion construction on steep slopes and for the long span. While alternative A has 0.7 mile more muskeg/wetland potential cross- ing than alternative C, it has the least amount of unroaded area of all the alternatives and the fewest miles of line at eleva- tions above 500 feet. Biological and Social/Cultural Constraints. Preference with respect to reducing or avoiding potential impacts on environmental resources favors alternatives B and D. Alterna- tives A and C both potentially parallel more anadromous streams and impact more shellfish harvest areas (Table 6-8). Further- more, the cable crossing for both routes A and C crosses close to winter herring grounds located on the south shore of Behm Canal. Social and cultural resource impacts are also higher with alternatives A and C, notably due to the visual and cultural resource impact potential associated with segment 8.2 in both alternatives. As proposed, segment 8.2 would cross in the immediate area of a U.S. Forest Service recreation cabin located at Anchor Pass. It would also present significant visual impacts to Point Lees which is a prominent land form located at the intersection of Bell Arm and Behm Canal. Point Lees is also the site of a former large native village, as mentioned in Captain George Vancouver's ship log (Appendix C and D). Between the two remaining alternatives, B and D, alterna- tive D is slightly preferred. This preference reflects U.S. Forest Service comments that segment 8.5, included in alterna- tive B, has higher primitive recreation value than alternative D and segment 8.6. Visually, segment 8.5 potentially impacts the Forest Service cabins on Orchard Lake. Parts of Segment 8.6 may also visually impact those cabins and create higher visual impacts to viewers from the water where it crosses Shrimp Bay and routes along the shore of Neet's Bay. 6.8-2 Cost. Comparison of the total costs of the four alterna- tives favors alternative B. Alternative B would cost approxima- tely $500,000 less than alternative D, and $1.4 to $2.0 million dollars less than either alternatives A and C. The higher cost of the steep slope construction and aerial crossing of Bell Arm in alternatives B and D, is more than off-set by the 1.3 addi- tional miles of cable crossing associated with alternatives A and C. Selected Alternative Based on the information presented, alternative B is selected as the preferred route, but is only slightly more pre- ferable than alternative D. Overall, alternative B was slightly better, technically, than alternative D because of its shorter length, (7.3 miles) less routing through roadless areas, and avoidance of spanning Shrimp Bay. These factors were considered to off-set the higher impacts of alternative B on recreational resources. Should more roads be constructed adjacent to segment 8.6 in the future, alternative D should be reconsidered. Upon review of the draft of this report, the U.S. Forest Service suggested that segment 8.1 be constructed on the west side of Eagle River because of the steep slopes on the east side. This refinement is shown in Figure 6-8. 6.8-3 seoment GO Z7VEE LAKE - SWAN LAKE seament| SE ALASKA INTERTIE Go ALTERNATIVE COMPARISON J SUMMARY ae ot SAUL ML) AL VIL([), mae ner.: secments Para: 21 EL,44+BSEBET? 12-7 | 7) ere: BOL E4 OE OT a ETT 7 om TT oe a a2adbe.a? : [pena MT ——— = 7/| NOTES/COMMENTS MAJOR STREAM CROSSING VALANCHE STEEP SLOPE AREAS ELEVATION 500 1500 FEET 1500 FEET EXPOSURE RIDGE TOP CROSSING ACCESS ROADLESS AREAS MUSK E G/WE TLAND POTEN ANADROMOUS STREAMS CROSSED ANADROMOUS STREAMS PARALLELED = SHELLFISH HARVEST ‘SPAWNING AREAS mi WATERFOWL USE AREAS EAGLE NEST SITES Eee Se oe = ee Sa LAND USE WILDERNESS AREAS USFS. Luo2/LU03 meme AIRPORTS (withun 1 mite) DESIGNATED REFUGES. PARKS " VISUAL IMPACT FERRY ROUTES o fo: : TRAILS/CABINS CAMPGANOS | FLY FRE MAT IO PLEY ye) OTHER USE AREAS Z nF 7 CULTURAL SITES. EXISTING/POTENTIAL : LAND STATUS FEDERAL/STATE 4 y I 7 4 08, LOCAL GOV'T PRIVATE/PRIVATE SELECTION m[ — [T_T Powis nsw WZNTIIIIN ILLIA LINN LLL YL CABLE OC AC é OVERHEAD BASE _ S48. — Sm Tb S a st score rock — 7B sim ENGINEERING PREFERENCE MEA musKecwe Land 7 7F _ sim t ENVIRONMENTAL PREFERENCE = 4275. B ar D ADDITIONAL COSTS ( add to above) ECONOMIC PREFERENCE [MJ b. ROW CLEARING __ _ FF sim HELICOPTER CoNsTR, ZO sim 0 TERMINALS: AC TERMINAL 7 ie OC CONVERTER STATION $ 3 ALTERNATIVE SELECTED CONTINGENCIES = FOR ECONOMIC ANALYSIS : , ENG., ADMIN. CM., LAND / , 28,903 a0827 2942/ HARZA ENGINEERING CO. ocr. 1987] ¢ 9 F1E8vL FIGURE §-8 @ TYEE LAKE HYDRO PROJECT | 4 LEGEND: s Se mem PREFERRED ommmmms EX ISTING/ ROUTE PLANNED ROADS ome ome ALTERNATIVE eee? AGENCY Ht HE ROUTES SUGGESTED ELIMINATED REFINEMENT. FROMFURTHER ———-— WILDERNESS SCREENING BOUNDARY cme somme EXISTING T/LINE SCALE 0 / 2 4 MILES & ed “ALASKA POWER AUTHORITY SOUTHEAST INTERTIE PROJECT SEGMENT 8 TYEE LAKE — SWAN LAKE ROUTE ALTERNATIVES HARE A ENGINEERING COMPANY GATE 4 SEGMENT 9.0 KETCHIKAN TO PRINCE OF WALES ISLAND Description of Alternatives Two route alternatives were identified to connect the pro- posed intra-island transmission line at Thorne Bay with the existing power grid in Ketchikan. Both routes exit Ketchikan via underwater cable near Mud Bay, come ashore on Prince of Wales Island at Grindall Point and then follow the north shore of Kasaan Peninsula for about five miles. At this point, alter- native A turns to the west and follows the south shore of Kasaan Peninsula, while alternative B continues along its north shore. The two alternatives come together near Tolstoi Bay and then follow the same route segment northwest to an intersection with the proposed intra-island transmission system west of Thorne Bay. Comparison of Alternatives Table 6-9 summarizes information used in the following comparisons: Route Length. The shortest route is alternative B, by 1.4 miles. Both routes have the same length of cable (17.2 miles). Physical Constraints. Alternative B is the preferred route with respect to evaluation of physical constraints. It crosses 4.7 miles less roadless area. Alternative B also crosses 1.3 miles less muskeg/wetland area than does alternative A. Biological and Social/Cultural Constraints. As indicated in Table 6-9, route preference with respect to the evaluation factors inventoried is mixed. Both routes cross the same number of anadromous streams (13), but alternative B has fewer miles of route parallel to streams (1.8 miles). Potential impacts to eagle nest sites, clearly favors alternative A, with 13 sites in proximity to the route. In comparison, alternative B has 23 eagle nest sites inventoried. Alternative A is preferable with respect to minimizing visual impacts. While miles of potential visual impact to Ferry routes are close (10.3 and 12.3 miles), alternative B's 12.3 miles is more significant since it is potentially visible to tourists on the main inland passage route, while alternative A's 10.3 miles would be viewed by users of the Prince of Wales Ferry route to Hollis. The latter is largely a local shuttle route between Ketchikan and Prince of Wales Island. G.9=1 Much of Prince of Wales Island is in native ownership. This is reflected by the relatively higher number of route miles in private land status for this study segment compared to other segments in the study. Typically, routing through privately owned land is less desireable than a route through federal, state or local government owned land. Land acquisition costs are usually higher and opposition is often high, and can lead to lengthy negotiation or condemnation proceedings. Alternative route B is less constraining in terms of rout- ing though private land, having 10.4 miles routed through private/private selected lands. In comparison, alternative A has 11.7 miles routed through the same category. Few land use conflicts are expected to result from either route. The majority of both routes are in the Forest Services's LUD IV category which places emphasis on resource development. Alternative A does route through or near the community of Kasaan, which may be of concern to local residents with respect to the line's visual impact. It should be noted that because the proposed line is a DC circuit, Kasaan could not be served by the system without an AC connection from the proposed DC converter station. Costs. Total project costs favor alternative B, but not significantly. Total costs for routes A and B are $43.46 and $42.72 million respectively. Less than $800,000 separate the two routes. Selected Alternative Alternative route B is selected as the alternative for economic analysis because it has the least cost, and is tech- nically preferred. The relatively close cost and mixed environmental prefer- ences between the two routes, however, necessitates that, should this segment be pursued as part of the Intertie system, detailed studies should be conducted on both routes. 6.9-2 . PROPOSED INTRA—ISLAND T/LINE mae ANTRA—ISLAND T/ LEGEND: “8 emme PREFERRED omens EXISTING ROUTE PLANNED ROADS meme ALTERNATIVE *& @¢ © * AGENCY SQUTHEAST INTERTIE R SUGGESTED oe Ht Ht Se eh REFINEMENT SEGMENT 9 FROM FURTHER —=—-——~ WILDERNESS KETCHIKAN — PRINCE OF WALES 1S. SCREENING BOUNDARY me aon SE oe ——+—— EXISTING T/LINE ROUTE ALTERNATIVES HARZS ENGINEERING COMPANY OATE: OT 168? Re ¥ ” RATSALLE tet R—-O BUN SEGMENT 10.0 SWAN LAKE TO QUARTZ HILL Description of Alternatives Alternatives to connect the Quartz Hill Molybdenum Mine site to the Swan Lake Hydroelectric site were investigated for two principal reasons. First, Quartz Hill represents a large load center which could take advantage of surplus energy offered by an Intertie System. Secondly, the Quartz Hill site is on one logical route for a Southeast Intertie link connecting to Canadian generation sources. Another Southeast Intertie link to Canada, at Prince Rupert, was evaluated, but found not to be feasible because of physical constraints to underwater cable construction and cost considerations (see Segment 11 and 15 discussions). Several segment links were identified for connecting Swan Lake and Quartz Hill (Figure 6-10). After review of these seg- ments links by Agencies, several modifications were made. Two segment links were eliminated from further comparison because of their potential for impacting high recreational values in the Gokachin and Mesa Lakes region of the Misty Fiords National Monument. Several refinements and additions were made as a result of discussions with Ketchikan District Forest Service personnel. The eastern terminus of all the Behm Canal cable crossings was relocated from Point Trollup to a location near the mouth of Bartholomew Creek inside Smeaton Bay. This was done to reduce visual impacts which would have been quite prominent to the many viewers traveling up Behm Canal into Misty Fiords. Route segments that were added during the study (10.5, 10.6, 10.7 and 10.8) reflected the Forest Service's knowledge of existing and planned logging roads in the area east and west of Thorne Arm. In all, ten route segment links were identified which were combined to form eight route alternatives for comparison, as shown in Table 6-10. It is important to note that none of the eight alternatives avoid routing through the Misty Fiords National Monument. Therefore, regardless of the route selected, difficult and lengthy permitting procedures are expected. Following are general descriptions of the route alterna- tives: Beginning at the Swan Lake substation, all the alternatives route southward following planned logging roads along the eastern shore of Carrol Inlet (segment link 10.1). At a point 6.10-1 just north of Island Point and the Coast Guard Loran station, alternative A splits off from the rest of the alternatives and crosses into the Misty Fiords National Monument south of Ella Lake continuing to the shore at Behm Canal just north of Short Pass. From there, alternative A continues underwater to a point west of Bartholomew Creek on the north shore of Smeaton Bay. At this point altentive A routes overland up the Bartholomew Creek drainage, and then crosses the Wilson and Blossom Rivers before it reaches the Quartz Hill Mine site. Alternative D is identical to alternative A up to the point west of Bartholomew Creek. At that point alternative D contin- ues underwater to Wharf Point where it follows the south shore of Wilson Arm overland and through the proposed Quartz Hill tailings tunnel to the mine site (segment link 10.10). Alternatives B, C, E and F all route southeast from Segment link 10.1, following existing and planned logging roads on the east side of Thorne Arm before they turn east into Misty Fiords. Alternatives B anc C enter Behm Canal at a point north of Rudyard Island. Alternative E and F continue to follow the existing road system further south before they enter Behm canal near Fox Point. At Bartholomew Creek in Smeaton Bay, alterna- tives B and E follow the overland route segment 10.9 into Quartz Hill, while C and F continue underwater to Wharf Point (segment 10570). The last of the eight alternatives, G and H, follow the existing and proposed logging roads and the Forest Service sug- gested refinement on the west side of Thorne Arm (segment link 10.5). Both alternatives cross Thorne Arm with a submarine cable at Elf Point and follow segment 10.7 to Fox Point. At Bartholomew Creek, alternative G routes overland (link 10.9) and alternative H continues underwater to Wharf Point (link 10.10). Comparison of Alternatives Table 6-10 presents the segment link evaluation information summarized by the alternatives described above. Route Length. The shortest overall route is alternative D at 50.7 miles. The longest route is alternative G at 60.4 miles. The route with the shortest cable distance is alterna- tive B with 8.6 miles of underwater cable. In comparison, alternative D which is the shortest overall in length, has 15.4 miles of cable. Physical Constraints. Comparison of the physical con- straint factors in Table 6-10 indicates that all the alterna- tives are similar in the extent of physical constraints inven- toried. Alternative routes C and H can be considered to have 6.10-2 slight advantages over alternative F. Of the eight alternatives routes considered, these three alternatives C, F and H, appear to have the fewest overall physical constraints. While alter- native F is the same as C and D in steep slope miles and eleva- tion over 1500 feet, it crosses more muskeg area than the other two alternatives and has more roadless area than alternative H. Among the three alternatives, alternative C crosses the most roadless area; 22.6 miles compared to 20.0 and 16.9 miles for F and H, respectively. However, alternative C crosses the fewest miles of muskeg/wetland area, 12.9 miles, as compared to 15.9 and 14.2 miles crossed for alternatives F and H. One note of concern with these three alternatives and other alternatives that include segment link 10.10 is the proposal of U.S. Borax to use Wilson Arm as a tailings disposal site for its Quartz Hill Molybdenum Mine development. Presently, the revised Quartz Hill Draft Environmental Impact Statement (USDA 1987) proposes Wilson Arm as the preferred tailings disposal site. However, the Environmental Protection Agency (EPA), in its review of the Quartz Hill project, has recommended that the middle basin of Boca de Quadra be the location for the mine tailing disposal. If Wilson Arm remains as the tailings dis- posal site, all transmission line alternatives that include segment link 10.10 would be technically infeasible as routes, since they would pass through an area of active tailings deposi- tion and may be prone to cable movement or damage. Biological and Social/Cultural Constraints. Except for alternatives G and H, biological constraints are similar among the route alternatives. Sensitive resource areas noted by Agen- cies include a good bottom fishery in the vicinity of Short Pass. Alternatives A and D would need to be realigned to avoid impacts in this region. Other areas of biological sensitivity that were noted included concern for eagles and impacts to anadromous fish at the mouth of Calamity Creek. This location, in segment 10.1, is common to all alternatives. Segment 10.9 lies completely within the Misty Fiords Non- wilderness Area associated with the Quartz Hill Project. This segment is of particular concern for its potential impact on high value salmon spawning areas with consequent high use by eagles where the proposed route crosses the Wilson and Blossom Rivers. Alternatives A, B, E and G must deal with this con- cern. All the alternatives which include segment 10.5 cross the most anadromous streams (14). Segment 10.5 also routes between two waterfowl use areas, one located on Thorne Arm near Minx Island and the other located just to the west of Carrol Inlet. 6.10-3 As mentioned earlier, all alternatives pass through the Misty Fiords National Monument. Alternative C is the shortest route through the Monument with 2.2 miles crossed. Alternative B is next with 4.0 miles crossed. Alternative A is the longest crossing through the Monument Wilderness area with 12.1 miles. As expected, alternative A also affects more high value primi- tive recreation area, in the vicinity of Ella Lake. These figures do not include routings through the non-wilderness area of Misty Fiords National Monument. Alternatives A and B, which include segment link 10.9, would route through approximately 18 miles of non-wilderness area. Alternatives which include seg- ment link 10.10, such as alternative C, route through less non- wilderness area (11 miles) due to the more direct route taken by the underwater cable through the non-wilderness area. Cost. Alternatives A and B are preferred alternatives with respect to cost. Less than $200,000 separate the two. Alterna- tive A is the least costly, with a total estimated construction cost of $38.66 million. The most costly alternative is alternative H. Its total construction cost is estimated at $45.16 million. Selected Alternative The route selected for economc analysis is alternative B, consisting of segment links 10.1, 10.2, 10.4, 10.8 and 10.9. Technically, alternative B is less desireable than alternative H which is the engineering preference. However, the $6 million additional cost for alternative H, in addition to the tailings disposal issue associated with link 10.10, eliminate this alter- native H from further consideration. With respect to overall environmental resources, alterna- tive C is slightly preferred to alternative B. Alternative C was eliminated, however, because it is $2.4 million dollars costlier than alternative B, and it includes segment link 10.10. Regardless of the route selected for this segment, an over- head transmission line through the Misty Fiords National Monu- ment will be difficult to achieve. Regulations under ANILCA (Title XI, Section 1110a) allow for routing utility corridors to inholdings within wilderness areas. However, ANILCA also states that such corridors must be compatible with the purpose for which the area was established, and that all feasible alternati- ves be evaluated. Field studies to support a detailed evaluation and an Environmental Impact Statement will be necessary and time con- suming, with no guarantee that the effort would be successful. 6.10-4 Routing through fewer miles of Monument Land will reduce study efforts but will not avoid the lengthy regulatory and permitting process. Consideration was given to extending a route south of Thorne Arm to Point Alva, thereby avoiding overhead line impacts to the Wilderness Boundary. However the alternative was reject- ed because it would add 9-10 miles of additional overhead line to the route, as well as 6-8 additional miles of cable, thereby making such a route prohibitively expensive. 6.1 0'—5 secment /O.O SWAN LAKE - QUART? We SEGMENT SE ALASKA INTERTIE ALTERNATIVE COMPARISON TELET eT LL 2 SUMMARY EVALUATION FACTORS CABLE ; 24 ae AE wel ae A: 01, LAE AG OVERLAND 44.@ re] Te: Mal, WZ 104 (08, /29 PHYBICAL CONBTRAWTS DP: Nhe HEE rl ean gt a NAF 3 trl, 10.2, 10.4 10,872.10 MAJOR STREAM CROSSING. ALT D: 0.4, 24 10/0 AVALANCHE STEEP SLUPE AREAS ae z5 az, Ag, 44670 ¥ (2 ELEVATION 500 1500 FEET ae WA Le , —= al, 129 >1500 FEET , EXPOSURE RIDGE TOP CROSSING ACCESS ROADLESS AREAS ie z MUSK EG/WETLAND POTENTIAL | /z.9| BIOLOGICAL CONSTRAINTS MEE nly coe TLL ii TIEXTLIZILA waresccmenenre ANADROMOUS STREAMS CROSSED * ANADROMOUS STREAMS PARALLELEO om ; + BASED ON THE REVISED DRAFT SHELLFISH HARVEST/SPAWNING AREAS mi /, i . ; QUART E Hi LL MINE e/ Ss, THE WATERFOWL USE AREAS eer ) £004 Tia/ OF FAL SELECTED EAGLE NEST SITES ; . THILINGS DSPOSAL SITE MAY 7a ALTEENATIVED LAND USE WILDERNESS AREAS get ge Lh fl ML laden auceae SOGANENT ID, USFS LUD2/LUD3 f bE zat 2 Aes 7 THE SOBMNARINE CHDLE L400 AIRPORTS (within 1 mite) 2 - fA WIL SA) RAZ, DESIGNATED REFUGES PARKS VISUAL IMPACT FERRY ROUTES TRAILS/CABINS CAMPGRNDS OTHER USE AREAS CULTURAL SITES EXISTING/POTENTIAL LAND STATUS FEDERAL/STATE LOCAL GOV'T ™ PRIVATE/PRIVATE SELECTION mm CABLE OC AC OVERHEAD BASE SI. SLOPE /ROCK _ ENGINEERING PREFERENCE #& : tz 7 A org ENVIRONMENTAL PREFERENCE # : 2 7. Caw 8 A ADDITIONAL COSTS ( add to above) ECONOMIC PREFERENCE [ALT Aor ROW CLEARING _ _ BS sim 7 HELICOPTER CONSTR. 2O_ _S/mi TERMINALS: AC TERMINAL OC CONVERTER STATION ALTERNATIVE SELECTED MIE CONTINGENCIES Z, 4 740| £360 FOR ECONOMIC ANALYSIS Ent AN, AMO zi Zao otest beeol See we * SEES SE PUNE Hie TOTAL IG 805)| 41075 | 4G Ho | AL 256| Ab 2Z76| 42 FS | AS /O4 HARZA ENGINEERING CO. SWAN LAK HYDRO PROJE! LEGEND: Sa meme PREFERRED ome EXISTING/ \ ROUTE PLANNED ROADS # omen ome ALTERNATIVE oeee* AGENCY SUGGESTED Ht Ht Pearcy REFINEMENT FROM FURTHER —-~-~ WILDERNESS SCREENING BOUNDARY wom some EXISTING T/LINE SRAGWwAY SEEN LS | Mi At Ve rensaung Col Mo JORDS NATIONAL» iT a Soe o oF Rie TUNNE HILL Bs MINE SITE mer SEGMENT 10 SWAN LAKE ~ QUARTZ HILL ROUTE ALTERNATIVES #i-—@ aun SEGMENT 11.0 QUARTZ HILL TO B.C. Description of Alternatives One route was identified to connect Quartz Hill to the Canadian Power Supply in Kitsault, British Columbia. Such a connection would provide dependable hydroelectric power to Quartz Hill and reduce dependence on diesel generation which is more costly per kilowatt hour to use and produces undesirable air quality impacts. An additional reason for evaluating this segment is to determine the feasibility of connecting Canada's surplus genera- tion with an intertied system in Southeast Alaska. Segment 11 would be one logical route for such a connection from the south because of the Quartz Hill load demand and because the route is both direct and technically feasible. The route described below was identified previously in studies done for Quartz Hill. The location of the U.S. portion of the route is indicated on Figure 6-11. The system proposed for this segment is bipolar 100 kv DC. The DC transmission facilities will provide better control for compensating for fluctuations between the different Canadian and U.S. operating systems. The proposed 100 kV DC. line would exit a DC converter station at the Quartz Hill Mine site, cross White Creek and then follow the Hill Creek drainage into the Keta River Valley. There it would cross the Keta River and continue to the southeast, following an unnamed drainage into the Marten River Valley. At this point the proposed route turns east to follow the Marten and Tombstone Rivers to Tombstone Bay on the Portland Canal. Here, it would cross the canal with two DC underwater cables (one for each pole) and connect with Canadian power facilities. Portland Canal would also be the site of a sea return electrode for the DC system. Consequently, the line from Quartz Hill to Portland Canal must carry three conductors and will have an appearance similar to a 138 kV AC H-frame transmission line. The total length of the proposed route from Quartz Hill to Canada is 26.3 miles, including 1.8 miles of underwater DC cable to the Canadian side of Portland Canal. Technically, the line is considered feasible but it will be difficult to construct and maintain. At least four miles of steep slope construction would be required as well as five miles of construction in muskeg/wetland area in the Marten and Keta River Valleys. All of the overhead portion of the line would require helicopter construction and maintenance due to its remote and roadless location. 6.11-1 Much of the route's location adjacent to steep slopes is expected to be effected by avalanches. Areas of most concern regarding avalanches include the drainages north and south of the Keta River and the eastern 3 miles of the Tombstone River. Important environmental resources that may be affected by the route include a waterfowl use area where the line crosses the Keta River and several important salmon streams. The route would follow the Tombstone River for 10.6 miles, the Marten River and associated tributaries for 6.0 miles, the Keta River and tributaries (including Red, Hill, and White Creeks) for 9.0 miles, and Beaver Creek for 0.5 mile. According to Alaska Department of Fish and Game personnel, the Tombstone River is a particularly important salmon stream and crossing it should be avoided (Appendix D). In addition to the above environmental resource concerns, approximately 17 miles of the proposed route crosses through Misty Fiords National Monument Wilderness area. Concerns and issues related to this impact will be similar to those discussed for the segment 10 routes. Costs The total construction cost for Segment 11 is estimated to be $39.29 million. This estimate includes the cost of a DC converter station at Quartz Hill and the cost of construction to the Canadian side of Portland Canal. 6.11-2 LEGEND: =e meme PREFERRED ROUTE = — ALTERNATIVE Ht Ht ROUTES ELIMINATED FROM FURTHER SCREENING ——- sw EXISTING T/LINE ome EXISTING/ PLANNED ROADS§ AGENCY SUGGESTED REFINEMENT WILDERNESS BOUNDARY FIGURE 6-11 SEGMENT 11 QUARTZ HILL — B.C. ROUTE ALTERNATIVES SEGMENT 12.0 KETCHIKAN TO METLAKATLA Description of Alternatives Three system alternatives were identified for connecting Metlakatla to Ketchikan. These alternatives, described in Chapter 2, included: Uc A 69 kV connection through Ketchikan from Ketchikan Public Utilities' (KPU) Bailey substation to Metlakatla (alternative A). 2. A 69 kV connection from KPU's Mountain Point substation to Metlakatla with a 34.5 to 69 kV step-up transformer installed at Mountain Point (alternative B). 3% A 34.5 kV connection from Mountain Point substation to Metlakatla (alternative C). All three routes would follow the route described below and shown in Figure 6-12. Alternative B and C routes however, would start at Mountain Point rather than at Bailey substation. The proposed alternative A route would exit Bailey sub- station and follow the Tongass Highway east through Ketchikan to Mountain Point. This segment of the route would either parallel or carry the existing 34.5 kV transmission line as an under- build. At Mountain Point, the route would cross Revillagigedo Channel to Race Point on Annette Island. From there, the route would follow the lower elevations along the west shore of Annette Island to Metlakatla. From Mountain Point to Metlakatla, the proposed alternative A route is also the route for alternatives B and C. The total line length from Bailey substation is 22.5 miles. The length from Mountain Point is 15 miles. A one mile long AC underwater cable is included in the mileage totals. Route preference with respect to system considerations favors the 69 kV alternative to Bailey substation (alternative A), as it would avoid the possibility of disturbances originat- ing in the Metlakatla system from entering the KPU distribution system (see Chapter 2). This alternative, however would be more objectionable than the other two alternatives with respect to environmental resources as its location in Ketchikan would present additional visual and land use impacts. It is also the most costly of the three system alternatives with an estimated construction cost of $11.2 million compared to $8.1 million and $6.6 million for alternatives B and C respectively. 6.12-1 Constraints and impacts would be essentially the same for the three system alternatives on Annette Island. The 34.5 kv system would have a slightly narrower right-of-way than the 69 kV system but the difference would not be significant. Visual impacts would be high for the section of line located on the Race Point Peninsula because of that landform's high visibility to Alaska Marine Highway travelers passing to the north and west of the peninsula. This impact could be reduced by having the cable come ashore further up the peninsula west of Spire Island. This mitigation however, would add roughly one additional mile of cable, doubling the length of the cable segment. The rest of the route to Metlakatla would be visible to travelers on the water in and around Metlakatla. Because of topographic constraints, alternative locations for the line through this section are very limited. For the economic evaluation of this interconnection, the least cost alternative, 34.5 kV from Mountain Point, was selected. 6.,112=—2 wrentie seaments |seoment 72:0 NETCHIKAN - METLARATE a SEGMENT SE ALASKA INTERTIE /Z.0 ALTERNATIVE COMPARISON ROUTE ALTERNATIVES e SUMMARY pee SII pe aT as J ar ner: secments CABLE en CG LI BAL BY - MES CALATA OVERLAND MET E: CFVLE ANT, Pil f — META LALLA EXPOSURE RIDGE TOP CROSSING SHELLFISH HARVEST/SPAWNING AREAS mil Zi a LIVEN) eal paz a ee = hit hmm hm LINILL, EAT TET TD TILL, pera: F48kV MAT, PT - METAR LAMUMLY SVESTATION MEK Lys oo oe ee SOCIAL/CULTURAL CONSTRAINTS == = ce se = = = = VS TEMA ND USE WILDERNESS AREAS AZ MTA LEGAEES ANEW OF EV LAI u! wit USFS LUD2/LUD3 c WEEKEND Ti 7Htovgy KETCH!- AIRPORTS (within 1 muted KAN. DESIGNATED REFUGES’ PARKS " VISUAL IMPACT FERRY ROUTES YET Ad = VEN ROLLE P. SEE = TRAILS/CABINS CAMPGARNDS OTHER USE AREAS CULTURAL SITES: EXISTING/POTENTIAL LAND STATUS: FEDERAL/STATE LOCAL Gov't eo. LLM LLIN LLLLIMTLLLLL LLL LLL LLL Fotos cowramrs —~ 7/TZMAUIMIIIL LLL LLL == = ZLIMLLLL LA MOresicommens ELEVATION 500 ISOOFEET »1500 FEET ANADROMOUS STREAMS CROSSED =| ALTERNATWES (AVOELVE LLET RIAL ANADROMOUS STREAMS PARALLELED =m ASPECTS OF CONNECTION Fbow 2t-9 318VL CABLE OC ac Overnean ease _ 722 . p ae a bc st store-nocn — “ES sim ng 7. ENGINEERING PREFERENCE : MUSKEG WETLAND 729. _ sim | 7 | 66 li 4 ENVIRONMENTAL PREFERENCE = ADDITIONAL COSTS ( add to above) ECONOMIC PREFERENCE : 4 ROW CLEARING _ _ _ bt sim HELICOPTER CONSTR, 22 _Svm rae pes maeants STATION % ALTERNATIVE SELECTED Vv - _ CONTIGENTIER Z. 725. Z FOR ECONOMIC ANALYSIS : : ENG. AOMIN.. CM., LAND LTS. core M22 | B/4Z HARZA ENGINEERING CO. OCT. 1987 FIGURE 6-12 ‘TO BAILEY.= . ‘SUBSTATION — ss id ; KN DT Pee \ MOUNTAIN POINT SUBSTATION A 5 - j 4 + 5 ne +. 4 e Pe et \ T | ae \ Be aed tee 4 feather 95 tN pee | < LEGEND: . 3a = mmm PREFERRED ome EXISTING/ £5 ty ROUTE PLANNED ROADS ] i z o=— == ALTERNATIVE + es ++ AGENCY | HE ROUTES SUGGESTED Ht ELIMINATED REFINEMENT FROMFURTHER —=-—— WILDERNESS SCREENING BOUNDARY ——e—— EXISTING T/LINE s 4 MILES e j a KAN = METLAKATLA ] PROPOSED ROUTE HARZ& ENGINEERING COMPANY GATE OCT 1987 SEGMENT 13.0 TYEE LAKE TO KETCHIKAN VIA CLEVELAND PENINSULA The route identified for this segment was developed in response to suggestions that the Ketchikan system could be provided with increased reliability if it were connected to Tyee Lake generation by a transmission line that was on a separate right-of-way from the Swan Lake line. Cleveland Peninsula was identified as a potential area for an alternative route to the Tyee Lake to Swan Lake intertie segment (segment 8). A route through Cleveland Peninsula could also provide for a shorter connection to Prince of Wales Island (segment 9), and provide the opportunity to supply energy in support of potential resource development on Cleveland Peninsula, as noted during meetings. For comparison purposes, one route through the Cleveland Peninsula was identified based on evaluation of physical and topographic constraints from USGS topographic maps, and Forest Service transportation inventory maps. The route was divided into two segment links to facilitate comparison with segments 8 (Tyee to Ketchikan) and 9 (Ketchikan to Prince of Wales Island). Segment link 13.1 is a 138 kV system routed from Tyee Lake to Ketchikan. Segment link 13.2 is a 69 kV system routed from a remote substation on Cleveland Peninsula to Thorne Bay on Prince of Wales Island (Figure 6-13). Description of Alternatives Segment link 13.1 would exit the existing substation at Tyee Lake and parallel the existing 138 kV transmission line for about 11 miles before it turns south. From this point the line would continue south passing two miles to the east of Boulder Lake. South of Boulder Lake, the route turns to the southwest and continues to the shore of Seward Passage. There it follows steep terrain and the shore to the head of Santa Anna Inlet before it turns south through drainages and comes out west of Spacious Bay. From there, segment link 13.1 routes through the Hofstad Creek drainage before it crosses over a low pass to terminate at the proposed remote substation site located ap- proximately one mile northwest of the head of Helm Bay. At this site segment 13.1 turns east following the shore of Helm Bay to Helm Point. At Helm Point the line crosses Behm Canal via an AC submarine cable to the vicinity of Survey Point. It then continues overland paralleling the Tongass Highway for most of the way beyond Ward Cove to the Bailey substation site in Ketchikan. 6513-1 The segment link to Prince of Wales Island (segment 13.2) begins at the proposed remote substation site northwest of Helm Bay. The proposed 69 kV line would exit the substation to the northwest and follow the Black Bear Creek drainage to a point south of Union Bay. There it would turn west to the shore of Clarence Strait and cross underwater with an AC cable to Thorne Head on the Prince of Wales Island. At that location, the route would cross overland to Thorne Bay where it would connect with the proposed 69 kV intra-island transmission system. Segment Comparison No route alternatives were identified for segment 13. In terms of the Intertie system, however, segment 13 is essentially an alternative to segments 8.0 and 9.0 discussed earlier. The following comparison, therefore, is based on a general assess- ment of segments 13.1 and 13.2 as compared to their alterna- tives, segments 8.0 and 9.0. Cleveland Peninsula/Ketchikan vs. Tyee Lake/Swan Lake (Segment $8.0). ©. TO Route Length. Between the two routes from Tyee Lake to Ketchikan, segment 8 (Figure 6-8) is substantially shorter, notably because it stops at Swan Lake and then uses the existing Swan Lake line to feed into Ketchitkan. The preferred segment 8 route has a total length of 50.5 miles, including 0.6 miles of cable. In comparison the Cleveland Peninsula route is approxi- mately 87 miles long, including 9.5 miles of cable. Physical Constraints. General comparison of physical constraints associated with the two routes indicates a prefer- ence for the Tyee Lake to Swan Lake alternative (segment 8). While muskeg/wetland and steep slope constraints appear similar, all of the Cleveland Peninsula route would require helicopter construction. In contrast only about half of the length of segment 8 is roadless. Environmental Constraints. In general, environmental constraints are anticipated to be greater with the Cleveland Peninsula to Ketchikan route. In addition to being longer, this route passes close to several bays which tend to experience higher waterfowl use and eagle concentration than other loca- tions. Additionally, the Cleveland Peninsula route is expected to create significantly more land use related impacts because of its routing through Ketchikan. Costs. Total estimated construction costs clearly favor the Tyee Lake to Swan Lake alternative. Total costs for segment 8 are approximately $28.9 million. In comparison, the estimated cost to construct segment 13.1 is roughly $50.3 million. 6.13-2 Cleveland Peninsula/Prince of Wales Island (Segment 13.2) - Ketchikan/Prince of Wales Island (Segment 9) Comparison In order to compare segment 13.2 with segment 9 (shown in Figure 6-9), it is assumed that segment 13.1 is in place. Based on a general review of both segments it can quickly be deduced that segment link 13.2 is preferable to segment 9 in comparison of physical, and environmental constraints, as well as cost. Segment link 13.2 is much shorter 19.5 miles compared to 43.8 miles for segment 9. Segment 13.2 also has about half the cable length of segment 9 (9 miles of AC versus 17.2 miles of DC cable). Segment 13.2 would be expected to cross some muskeg/ wetland area in the Black Bear Creek drainage. Constraints related to steep slope construction however, would be negli- gible. In comparison, segment 9 crosses about 9 miles of muskeg and 3 miles of steep slope. Segment 13.2 will have significantly less environmental impact. Areas of environmental concern are expected to be impacts to anadromous fish and eagles because of the line's route parallel to Black Bear Creek and visual impact to travelers on the State Ferry in Clarence Strait. However, visual impact of segment 9 on those same viewers would be more significant since segment 9, parallels Kasaan Peninsula which is also visible to travelers of Clarence Strait. Cost for segment 13.2 is estimated at $22.1 million. In comparison, segment 9 is estimated to cost approximately $42.7 million. Selected Alternative Based on the above considerations, the selected intertie connection is segment 8, Tyee Lake to Swan Lake, and segment 9, Ketchikan to Prince of Wales Island. This selection is based on the following conclusions: 1. The Tyee Lake to Ketchikan route via Cleveland Penin- sula (segment 13.1) is not justified on its own merits. 2. While the transmission connection between the remote substation to Prince of Wales Island (segment 13.2) is preferable when compared only to segment 9, it must have segment 13.1 to be feasible. 6.13-3 The interconnection of Tyee to Prince of Wales Island (either via segments 8 and 9 or via segments 13.1 and 13.2) must be assumed to make the Cleveland Peninsula route economically attractive. As discussed in Chapter 7 this was done and based on the analysis presented therein, the question was resolved in favor of segments 8, the Tyee-Swan Lake interconnection, and segment 9, Ketchikan-Prince of Wales Island. 6.13-4 i 5 MILES LEGEND: SKAGWAY PLANNED ROADS oe EX ISTING/ AGENCY ROUTE om — ALTERNATIVE Ht +H ROUTES =m mem PREFERRED ALASKA POWER AUTHORITY SOUTHEAST INTERTIE PROJECT SUGGESTED 13 — KETCHIKAN — PRINCE OF SEGMENT TYEE LAKE WALES ISLAND VIA CLEVELAND PENINSULA } REFINEMENT —— > | WiLDERNESS ELIMINATED i H i BOUNDARY FROM FURTHER SCREENING ——a—— EXISTING 7 COMP tin PROPOSED ROUTE THLINE SEGMENT 14.0 HAWK INLET-HOONAH TO SITKA Description of Alternatives During the Public and Agency meetings conducted in January 1987, it was suggested that a transmission intertie, routed down Chicagof and Baranof Islands rather than from Snettisham to Kake, would better serve local communities and future develop- ment potential. In response to these comments an alternative intertie route was identified, as shown in Figure 6-14, and compared to the Snettisham to Kake connection (segment 5.0). The required system voltage was determined to be 138 kV AC, versus 100 kv DC for Snettisham to Kake. This route, termed the West Route, begins at Hawk Inlet where it connects to the Juneau power grid via a 138 kV Juneau to Green's Creek transmission line segment (segment 3.0). From Hawk Inlet the route crosses Chatham Strait to Chicagof Island north of Whitestone Harbor with a 138 kV AC submarine cable and continues into Hoonah where a substation would be constructed to step down the voltage for local use. From Hoonah, the.138 kV line would follow existing forest Service logging roads!/ south into the Game and North Creek drainages. The route crosses over the pass between the North Creek and Freshwater Creek drainages and follows existing log- ging roads to Tenakee Springs, where a substation would be con- structed. At Tenakee Springs, the proposed line crosses Tenakee Inlet with an AC underwater cable coming ashore east of Kadashan Bay. It then turns south, following existing logging roads in the Kadashan River Valley to a point just northwest of the head of Sitkoh Bay. At this location an optional remote substation could be constructed to facilitate a 69 kV spur to Angoon (segment link 14.5). Whether or not the Angoon spur is constructed, the 138 kv system would continue south following existing logging roads, for the most part, past Sitkoh Lake to Point Lindenburg. There, it would cross Peril Strait, via submarine cable, and exit at Point Moses on Baranof Island. From Point Moses the proposed route begins to follow more rugged and remote terrain. The route crosses north of Lake Eva following a narrow valley to planned logging roads west of i/ As noted in the Tongass National Forest Logging Operation Plan EIS for Chicagof Island (USDA, 1986). 6.14-1 Middle Arm Kelp Bay. At that point it turns west, crosses a high elevation pass into an unnamed drainage south of Annahootz Mountain. There, it turns south to follow existing logging roads and narrow drainages into the Indian River Valley, finally connecting with the existing transmission system in Sitka with the construction of a substation expansion at Blue Lake Power- house. (Also see the discussion of the City of Sitka's pre- ference, given in Appendix D and section 6.7 herein). For comparison to the East Route, as a part of a total Southeast Intertie system, the West Route must continue from Sitka to Kake as described in the discussion of segment 7. The total length of the West Route is 204 miles, including the Juneau-Green's Creek 138 kV line and Sitka-Kake. Approxima- tely 63 miles of that total are underwater AC cables. The following section compares the technical, environmental and economic merits of this West Route with its East Route counter- part, Snettisham to Kake (Segment 5.0). Segment Comparison Evaluation constraint factors were not inventoried for the West Route, as they were for the segments identified in the initial stages of the study. Even so, general comparisons with respect to technical and environmental aspects, as well as assumptions regarding costs can be made to support the conclu- sion drawn. Route Length. Total length favors segment 5, the Snettisham to Kake route. It is 115 miles shorter than the West Route. However, it has almost the same cable length as the West Route, 63 miles. Physical Constraints. Technically, the Snettisham to Kake route would be easier to construct and maintain, primarily because of the physical constraints associated with overland construction. The long single cable of segment 5.0 would not represent a greater risk factor over the several shorter cable lengths required with the West Route. Greater cable risk may be associated with the several smaller crossings since the poten- tial for near shore hazards such as tidal fluctuations and anchor dragging would be greater with several crossings. While the Snettisham to Kake route is preferred technical- ly, the West Route does not actually encounter difficult physi- cal constraints until it nears Sitka. Refinements to the route in this area, may reduce some physical constraints encountered. 6.14-2 Biological and Social/Cultural Constraints. The Snettisham to Kake route is clearly preferred with respect to minimizing environmental impacts. Fish and Wildlife Service eagle surveys indicate many eagle nest sites along the shores of Chicagof Island in the vicinity of the cable crossing locations for the West Route. In addition, the West Route would affect more recreation areas as it passes near several Forest Service recreation cabins located on lakes near the route. Visual impacts would be higher as well, particularly as the route nears Sitka and begins crossing high elevation passes and approaches the Katlian Bay area. The route's crossing of Peril Strait would also be visible to State Ferry travelers. Costs. Comparison of the estimated construction costs for segment 5 and segment 14 favor segment 5, Snettisham to Kake. Costs estimated for the West Route are about $165 million including the 138 kV Juneau-Green's Creek and the Sitka-Kake segment. In comparison, Snettisham to Kake's estimated construction cost is about $58 million. Selected Alternative As a link in the Southeast Intertie connection, Snettisham to Kake is the preferred route. The West Route does have the advantage of picking up the energy loads of Hoonah, Tenakee and Sitka, but on all other technical, environmental and economic counts, it is less desireable in comparison to the East Side Route. With the East Route, the load centers on Chicagof and Baranof Islands can be interconnected to the Southeast Intertie system subsequent to its initial operation, if economic condi- tions dictate. Based on the above conclusions, segment 14 is not preferred as part of the Southeast Alaska 138 kV Intertie system. However as discussed in Chapter 7, an economic comparison was made between the West Route, serving Green's Creek, Hoonah, Tenakee Springs, Angoon and Sitka, and the East Route with a 69 kV spur from Juneau, serving the same load centers. 6.14-3 LEGEND: =m mm PREFERRED ome «EX ISTING/ ROUTE PLANNED ROADS om em ALTERNATIVE AGENCY Ht Ht RouTes SUGGESTED ELIMINATED REFINEMENT FROM FURTHER WILDERNESS SCREENING BOUNDARY —-— EXISTING T/LINE 2M ALASKA POWER AUTHORITY : SOUTHEAST INTERTIE PROJECT SEGMENT 14 HAWK INLET ~ HOONAH —TENAKEE ANGOON™SITKA ee NGINEERING COMPANY OATE.OCT 198 SEGMENT 15.0 QUARTZ HILL to PRINCE RUPERT, B.C. Description of Alternatives Segment 15 was considered as an alternative to the Quartz Hill-Kitsault, B.C. transmission line (Segment 11). Comparison of the two segments are summarized at the conclusion of this section. Like Segment 11, the required facility is a bipolar 100 kV DC transmission line with a sea return. The line would be predominantly a submarine cable but would have an overland portion, from Quartz-Hill to Smeaton Bay, along the route previously described as segment 10.9. The overhead portion of the line on the U.S. side would carry a third conductor for sea return from Smeaton Bay and thus would require wood H-frame line structures and have an appearance similar to the 138 kV AC lines. On the Canadian side, the overhead line would be bipolar DC on single wood poles. As shown on Figure 6-15, the submarine cable route for the line would follow Smeaton Bay, Behm Canal and the Revillagigedo Channel to the US/Canadian border, north of Dundas Island. From that point to Prince Rupert two routes were considered. Segment 15.1 continues southeasterly, passing northeast of Dundas Island and continuing to a landfall on the Tsimpsean Peninsula. From there, Segment 15.1 would follow an overland route to Prince Rupert. The total length of the route is 112 miles, of which 40 miles would be overhead construction and about 72 miles would be twin submarine cables. A bathymetric survey of this route was conducted by NOAA for the Power Authority in 19841/, The survey data indicate the presence of deep troughs and rocky ledges which may be unsuitable for submarine cables in the areas of Behm Canal and northeast of Dundas Island. The second route alternative shown on Figure 6-15 for the cable is Segment 15.2. This route passes to the west of Dundas Island through Caamano Passage and then turns east toward Prince Rupert, following Brown Passage, Metlakatla Harbor and Prince Rupert Harbor into Prince Rupert. The length of this alterna- tive is about 136 miles. About 117 miles of this length would be twin submarine cables and 19 miles would be overhead lines. Information from NOAA charts indicates this alternative passes through a large area south of Dundas Island that is designated as a dumping area and may be unsuitable for submarine cables. In addition, this route is exposed to the open ocean and high winds, south of Dundas Island, which could adversely impact cable installation and reliability. A/ International Technology Limited; Hydrographic Survey Data Processing For Southewast Alaska Interties; January 1986. 6.15-1 As noted above, both of the considered Quartz Hill to Prince Rupert routes may have flaws which could make a submarine cable installation inadvisable. Of the two, the easterly route, Segment 15.1 was selected for comparison with Segment 11.1 based on its shorter length and because it is the more sheltered of the two routes. Segment Comparison The estimated cost of the entire Segment 15.1 is approxima- tely $110 million. The cost of facilities within the U.S. border is estimated to be about $70 million. In contrast the interconnection of Quartz Hill with B.C. Hydro via Kitsault is estimated to cost about $70 million in total and about $40 million for the U.S. facilities. From an environmental stand point, the Quartz Hill to Prince Rupert Route, Segment 15, is preferable to Segment 11 which requires a corridor through the wilderness area of Misty Fiords National Monument. Segment 15 requires a corridor only through the non-wilderness area of the Monument and therefore presents a lesser social/cultural impact. Though segment 15 is preferred with respect to environ- mental resources, segment 11 is the selected alternative for connecting Quartz Hill to B.C. Hydro. This conclusion is based on the considerably lower cost of segment 11 and because the route presents fewer technical difficulties compared with those of segment 15. 65 15=2 AIVVUIk Vr LEGEND: PLANNED ROADS ome EXISTING/ o0es* AGENCY eee PREFERRED SUGGESTED REFINEMENT —--—— WILDERNESS m= ALTERNATIVE ELIMINATED Hh -+H+ ROUTES FROM FURTHER SCREENING —-— EXISTING T/LINE BOUNDARY 6 MILES ALASKA POWER AUTHORITY SOUTHEAST INTERTIE PROJECT SEGMENT QUARTZ HILL — PRINCE RUPERT ROUTE ALTERNATIVE FIGURE 6-16 SKAGWAY HAINES HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS GENERATION SOURCES EXISTING T/LINE PROPOSED T/LINE LENGTH, MILES 25.6(U.S. ONLY) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY LENGTHS OF SELECTED ROUTES H4ARZA ENGINEERING COMPANY CcTose= 1967 Chapter 7 ECONOMIC EVALUATION OF INTERTIE ALTERNATIVES Introduction This chapter describes formulation of several system expan- sion plan alternatives for the Southeast Intertie and the cri- teria, methodology, and results of economic analyses performed to determine which alternative plan is the most economically desirable. The selection process was performed in two parts. A preliminary economic screening was performed to identify the most favorable alternatives. These alternatives were then analyzed in more detail using economic assumptions adopted for this study. The final results yield a recommended Intertie expansion plan and a chronology of development. Description of Alternative Plans The route selection studies, described in Chapter 6, resulted in the identification of the recommended routings for the transmission lines which, if constructed, would form the Southeast Intertie System. This chapter presents studies of various combinations of these transmission lines which were grouped into alternative systems, analyzed and compared. Table 7-1 presents the alternative systems studied. As shown in the table, the alternatives were grouped under five general headings with subgroupings. The five headings are as follows: Alternative I - Base Case Alternative II - Southeast Alaska Connections Alternative III - Power Supplied from N.C.P.C. Alternative IV - Power Supplied from B.C. Hydro Alternative V - Power Supplied from Both N.C.P.C. and B.C. Hydro i The major subgroupings were developed to allow the analysis of possible subsystems, based on geographic location, which were identified during the course of the study, to allow comparison of unresolved routing questions and to allow an assessment of the effects of the Quartz Hill Mine on the expansion plan alter- natives. Figure 7-1 shows the geographic divisions identified, with maximum development in each separate system indicated. 7-1 FIGURE 7-1 WHITEHORSE SS SKAGWAY ™~. O HAINES HOONAH @ OS™ GREENS CREEK NORTHERN SYSTEM > SRATER LAKE TENAKEE SPRINGS PETERSBURG NORTHERN, CENTRAL, OR SOUTHERN SYSTEM SOUTHERN SYSTEM PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS GENERATION SOURCES KETCHIKAN EXISTING T/LINE PROPOSED T/LINE QUARTZ ALTERNATIVE T/LINE METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY GEOGRAPHIC SUB-SYSTEMS HARZA ENGINEERING COMPANY OCTOBES 1967 Figure 7-2 shows the two unresolved routing questions analyzed; East Route vs. West Route, and Cleveland Peninsula vs. Tyee-Swan Lake. The Quartz Hill question was investigated by inclusion or exclusion of the Quartz Hill load from the various alterna- tives. For radial lines, such as the Northern System line to Angoon and/or Sitka, via Green's Creek, Hoonah and Tenakee Springs, it is possible to investigate the economic desirability of an interconnection by analyzing the system without the radial line, or a segment of the line, and then adding the line and comparing the resulting B/C ratios. This approach was taken for analysis of the proposed radial lines to Haines, Skagway, Green's Creek, Hoonah, Tenakee Springs, Angoon, Sitka, Prince of Wales Island, and Metlakatla. 7-2 FIGURE 7-2 WHITEHORSE SKAGWAY HAINES HOONAH ee ~~ GREENS \ CREEK ‘ >) SNETTISHAM- ‘ CRATER LAKE TENAKEE SPRINGS y WEST ROUTE EAST ROUTE @ ANncoon PETERSBURG PRINCE LEGEND: OF WALES _ ISLAND == LOAD CENTERS ie CO) - GENERATION sources — EXISTING T/LINE PROPOSED T/LINE QUARTZ = ALTERNATIVE T/LINE METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ROUTING ALTERNATIVES HARZA ENGINEERING COMPANY Il. Table 7-1 INTERTIE ALTERNATIVES BASE CASE A. Diesel and Existing Hydropower Intertie Connections S.E. INTERTIE CONNECTIONS A. NORTHERN SYSTEM (Supplied by Snettisham and Crater Lake) 1. Juneau-Skagway 2. Juneau-Haines-Skagway Bis Juneau-Greens Creek (34.5 kV, 20 year life) 4. Juneau-Greens Creek (69 kV, 20 year life) 5. Juneau-Greens Creek-Hoonah 6. Juneau-Greens Creek-Hoonah-Tenakee an Juneau-Greens Creek-Hoonah-Tenakee-Angoon 8. Juneau-Greens Creek-Hoonah-Tenakee-Sitka 9. Juneau-Greens Creek-Hoonah-Tenakee-Angoon-Sitka 10. Snettisham-Kake-Sitka B. CENTRAL SYSTEM (Supplied by Tyee Lake) 1. Petersburg-Kake Ze Petersburg-Kake-Sitka Cs SOUTHERN SYSTEM (Supplied by Tyee and Swan Lakes) 1. Tyee-Ketchikan a. Direct Connection (Cleveland Peninsula) b. Connected via Swan Lake 2. Tyee-Ketchikan-Prince of Wales Is. a. Direct Connections from Tyee via Cleveland Peninsula b. Connected via Swan Lake and Ketchikan-Prince of Wales Is. SZ Tyee Lake-Swan Lake Plus: a. Ketchikan-Metlakatla (69 kV from Bailey) b. Ketchikan-Metlakatla, (via Mt. Pt., 34.5 kv) c. Petersburg-Kake-Sitka d. Swan Lake-Quartz Hill e. Ketchikan-Prince of Wales, and Swan Lake- Quartz Hill Table 7-1 (Cont'd) NORTH-SOUTH INTERCONNECTIONS WITH QUARTZ HILL ls (East Route), Juneau-Green's Creek, Snettisham- Kake-Petersburg, Swan-Tyee-Quartz Hill, Ketchikan-Prince of Wales Is. ?AG Same as above, plus Kake-Sitka 36 Snettisham-Kake-Petersburg, Tyee-Swan-Quartz Hill 4, (West Route), Juneau-Green's Creek-Hoonah- Tenakee-Angoon-Sitka-Kake- Petersburg, Swan-Tyee-Quartz Hill, Ketchikan- Prince of Wales Is. NORTH-SOUTH INTERCONNECTION WITHOUT QUARTZ HILL is (East Route), Juneau-Green's Creek, Snetthisham- Kake-Petersburg, Swan-Tyee, Ketchikan-Prince of Wales Is. Ze Same as above, plus Kake-Sitka Ss (West Route), Juneau-Green's Creek-Hoonah- Tenakee- Angoon-Sitka-Kake-Petersburg, Swan-Tyee, Ketchikan- Prince of Wales Is. III. POWER SUPPLIED BY N.C.P.C. A. NORTHERN SYSTEM ile Whitehorse-Skagway-Haines aie Whitehorse-Skagway-Haines-Juneau-Green's Creek- Hoonah-Tenakee-Angoon 3. Same as above, plus Sitka NORTH-SOUTH INTERCONNECTIONS WITH QUARTZ HILL We (East Route), Whitehorse-Skagway-Haines-Juneau- Green's Creek, Snetthisham-Kake-Petersburg, Swan- Tyee-Quartz Hill, Ketchikan-Prince of Wales Is. 26 Same as above, plus Kake-Sitka Sie Snettisham-Kake-Petersburg, Tyee-Swan-Quartz Hill 7-4 Table 7-1 (Cont'd) a (West Route) Whitehorse-Skagway-Haines-Juneau- Green's Creek, Snetthisham-Kake-Petersburg, Swan- Tyee, Ketchikan-Prince of Wales Is. NORTH-SOUTH INTERCONNECTIONS WITHOUT QUARTZ HILL ite (East Route) Whitehorse-Skagway-Haines-Juneau- Green's Creek, Snetthisham-Kake-Petersburg, Swan- Tyee, Ketchikan-Prince of Wales Is. 2 Same as above, plus Kake-Sitka 3. (West Route) Whitehorse-Skagway-Haines-Juneau- Green's Creek-Hoonah-Tenakee-Angoon-Sitka-Kake- Petersburg, Swan-Tyee, Ketchikan-Prince of Wales Is. IV. POWER SUPPLIED BY B.C. HYDRO A. SOUTHERN SYSTEM Nis B.C.-Quartz Hill ie B.C.-Quartz Hill-Swan Lake 3. B.C.-Quartz Hill-Swan Lake-Tyee Lake NORTH INTERCONNECTIONS WITH QUARTZ HILL iP (East Route) Juneau-Green's Creek, Snetthisham- Kake-Petersburg, Swan-Tyee-Quartz Hill-B.C. Hydro Ketchikan-Prince of Wales Is. 2. Same as above, plus Kake-Sitka 3. (West Route) Juneau-Green's Creek-Hoonah-Tenakee- Angoon-Sitka-Kake-Petersburg, Swan-Tyee-Quartz Hill-BC Hydro, Ketchikan-Prince of Wales Is. 4. B.C.-Quartz Hill-Swan Lake-Tyee Lake, Petersburg- Kake-Sitka Vv. POWER SUPPLIED BY BOTH B.C. HYDRO AND N.C.P.C HYDRO A. ONLY QUARTZ HILL SUPPLIED BY B.C. HYDRO 1. B.C.-Quartz Hill, Whitehorse-Skagway-Haines 2. B.C.-Quartz Hill, Whitehorse-Skagway-Juneau- Green's Creek-Hoonah-Tenakee-Sitka, Haines-Juneau =5 Table 7-1 (Cont'd) 3 Same as above, plus Haines and Angoon 4. B.C.-Quartz Hill, Whitehorse-Skagway-Haines- Juneau- Green's Creek-Hoonah-Tenakee-Sitka-Kake- Petersburg, Swan-Tyee, Ketchikan-Prince of Wales Is. (West Route) 5. B.C.-Quartz Hill, Whitehorse-Skagway-Haines- Juneau-Green's Creek, Snettisham-Kake-Petersburg, Tyee-Swan Lake, Ketchikan-Prince of Wales Is. (East Route) B. B.C. HYDRO AND N.C.P.C. INTERNCONNECTED 1. East Route without Kake-Sitka 26 East Route, Kake-Sitka 3. West Route Alternative I - Base Case Alternative I represents a scenario in which no new trans- mission lines would be built throughout the study period. Increasing loads were assumed to be met by excess hydro energy available and new diesel generators. Existing transmission lines are considered part of the base case. These include the Tyee Lake- Wrangell-Petersburg transmission line, the Snettisham-Juneau transmission line and the Swan Lake-Ketchikan transmission line. All alternative expansion plans will be compared to the base case scenario. See Figure 7-3. Alternative II - Southeast Alaska Connections Alternative II includes only Southeast Alaska interconnec- tion scenarios, i.e. intertie alternatives that do not include power imported from Canada. See Figure 7-4. The Northern System would be supplied by the Snettisham- Crater Lake Project and could include Juneau, Haines, Skaqway, Green's Creek Mine, Hoonah, Tenakee Springs, Angoon, Kake, and Sitka. The major load centers in the Northern System would be Juneau, Green's Creek and Sitka. There are two alternative intertie routes to Sitka. The "West Route" through Juneau- Green's Creek-Hoonah-Tenakee Springs-Sitka, and the "East Route" through Snettisham-Kake- Sitka. The second region, or Central System, would be supplied by Tyee and could include Wrangell, Petersburg, Kake and Sitka. The third region, or Southern System, could be supplied by Tyee Lake and Swan Lake and could include Ketchikan, Wrangell, Petersburg, Kake, Sitka, Prince of Wales Island, Metlakatla, and Quartz Hill. In this Southern 7-6 FIGURE 7-3 + WHITEHORSE > O SKAGWAY @ ON. ° 4 > 404 HAINES @ o™ GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS PETERSBURG WRANGELL 2. % z TYEE LAKE PRINCE LEGEND: OF WALES ISLAND SWAN @ - Load centers r 415kV LAKE 7 O GENERATION SOURCES KETCHIKAN Se o x EXISTING T/LINE — o —= PROPOSED T/LINE QUARTZ Js e AZ @ , > METLAKATLA ; O KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ALTERNATIVE | HARZA BASE CASE ENGINEERING COMPANY OCTOSE= FIGURE 7-4 WHITEHORSE SKAGWAY iw O ae? N, a Ad, s HAINES oN JUNEAU HOONAR GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG PRINCE LEGEND: OF WALES ISLAND @ - Load centers © - GENERATION SouRCES KETCHIKAN — - EXISTING T/LINE - PROPOSED T/LINE QUARTZ METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ALTERNATIVE II S.E. ALASKA SYSTEM HARZA ENGINEERING COMPANY OCTOBES FIGURE 7-5 WHITEHORSE SKAGWAY Sil legs nn tN, Ad, / Sa ) HAINES HOONAH GREENS + CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG PRINCE LEGEND: OF WALES ISLAND @ - Loan centers © - GENERATION SOURCES KETCHIKAN Deal EXISTING T/LINE PROPOSED T/LINE ; QUARTZ METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ALTERNATIVE Ill HARZA ENGINEERING SOMPANY . OCTOBES 1987 POWER FROM N.C.P.C. FIGURE 7-6 SKAGWAY HAINES HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG TYEE LAKE PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS © - GENERATION souRCES KETCHIKAN wee - EXISTING T/LINE PROPOSED T/LINE KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ALTERNATIVE IV POWER FROM B.C. HYDRO HARZA ENGINEERING COMPANY OCTOSES 1SE7 FIGURE 7-7 SKAGWAY HAINES HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS ANGOON PETERSBURG PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS @ GENERATION SOURCES KETCHIKAN — EXISTING T/LINE PROPOSED T/LINE QUARTZ METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY ALTERNATIVE V POWER FROM N.C.P.C. AND B.C. HYDRO OcTose= 1987 System, two alternative routes were considered for the Tyee- Ketchikan interconnection), one is to link Tyee directly to Ketohikan via Cleveland Peninsula and the other is to link Tyee to Ketchikan via a Tyae-Swan Lake interconnection. Total 8.B. System Intertie alternatives refer to the potential inolusion of all load centers in the system. Two main routes were considered for interconnecting the Northern, Central and Southern systems. The "East Route" refers to an interconnection of the three geographic subsystems via a Snettisham-Kake- Petersburg line and Tyee-Swan Lake. The "West Route" would entail interconnecting the three subsystems via Juneau-Hoonah, Sitka, Kake and Peters- burg, and the Tyee-Swan Lake line. Alternative III - Power Supplied by N.C.P.C. Alternative III involves the all 6.E. Alaska system, described in Alternative II, with an interconnection to the Northern Canada Power Commission (N.C.P.C.) grid at Whitchorse via Skagway. See Figure 7-5, Power to the Northern System and an entire 5.E. Alaska grid, with their variations, were investi- gated, Alternative IV - Power Supplied by 5.C. Hydro Alternative IV involves the all S.E. Alaska system, described in Alternative II, with an interconnection to Canadian generation sources in British Columbia via transmission lines from Kitsault, B.C. to Quartz Hill Mine and from Quartz Hill to the Swan Lake Project. See Figure 7-6. Power to the Southern System and an entire S.E, Alaska grid, with their variations, were analyzed. ‘ Alternative V - Power Supplied by Both B.C. Hydro and N.C.P.C. As indicated, power would be furnished from both the north and the south in Alternative Vv. Cases involving split grids, with each Canadian utility serving selected Alaska load centers, were analyzed, as well as an interconnection of the two Canadian utilities through Alaska. See Figure 7-7. The appropriate variations were analyzed. Criteria for Economic Evaluation The economic parameters and assumptions used in the evalua- tion of the various alternatives are based on guidelines sup- plied by the Alaska Power Authority and local utilities. The economic parameters detailed below are summarized on Table 7-2. 7-7 Table 7-2 MAJOR ECONOMIC CRITERIA le All Costs in 1987 Dollars. ie Present Worth Analysis: 1987-20341/ 3. Planning Horizon: 1987-2006 4. Discount Rate: 3.5 and 4.5 percent Sie Inflation Rate: 0 percent 6. Economic Life of Projects Diesel Generators 20 years Transmission Lines 30 years Hydroelectric Projects 50 years Te Annual Fixed Carrying Charges 20-year 30-year 50-year Life Life Life Cost of Money (%) 3.250) 3/350 3 150) Amortization (%) 3.54 1.94 0.76 Insurance (%) 0.25 0.20 0.20 Total (%) 7.29 5.64 4.46 1/ The last year of the planning horizon: 2034 corresponds to the last year of the 30-year economic life of transmission lines, assuming an on-line date in 2005. Planning Horizon The planning horizon, or period of study, selected begins in January 1, 1987 and ends December 31, 2034, the last year of the 30-year economic life of a transmission line built in 2005. The Power Authority guidelines prescribe a 20 year period for load and fuel forecasting, and expansion alternative enactment (1987-2006). For the period 2007 to 2034, all loads, costs, and expansion plans were assumed to remain constant. Present worth cost comparisons were made in terms of 1987 dollars using the discount rates described below. Discount Rates Two real discount rates of 3.5% and 4.5% were used in this analysis. The lower rate of 3.5% is used in the reference case described in the results. The rate of inflation was assumed to be zero percent throughout the study period. Table 7-2 summarizes the annual fixed carrying charges used in the study. These charges are the sum of the real interest rate, depreciation, and insurance. The project costs were depreciated using a straight line amortization based on the project life. The annual insurance cost for diesel generators was assumed to be 0.25 percent of the total investment cost. For hydroelectric facilities and transmission lines, insurance costs were assumed to be 0.20 percent of the total investment. Economic Lives The economic lives assumed for generation and transmission facilities are based on APA Guidelines. A life of 20 years was assumed for diesel generators, 30 years for transmission lines and 50 years for hydroelectric plants. For the period 2007-2034 all existing capacity remains fixed at the 2006 year levels. Load Forecasts Tables 1-2, through 1-4 show the load projections for the high, most likely, and low electric load demand scenarios that were used in the analysis. The projections for the major load centers are those presented in the R.W. Beck draft report dated December 22, 1986, except the projections for Juneau which are from an R.W. Beck report dated January 29, 1987. Projections for other load centers were developed based on information furnished by the Power Authority and from the Black Bear Lake es Project Feasibility Update Report (February 1987). Diesel Installed Capacity and Retirements Table 7-3 shows the 1986 installed capacity of generation facilities serving the various load centers and the assumed retirement schedule for the period 1987-2006. For the purposes of this study, the existing hydro generation projects in South- east Alaska were divided into two categories: local hydro projects, which have been developed by local utilities and were assumed to serve the local load exclusively; and system hydro projects, which were developed by State or Federal agencies and which were assumed to generate power and energy to be shared by interconnected load centers. Table 7-4 is a list of the so called "System Hydro" plants. All other existing plants were assumed to serve local loads. 7 Harza Engineering Company report for the Alaska Power Authority. T=9 Table 7-3 DIESEL RETIREMENT SCHEDULE Load Existing Center Capacity 1987 1968 1989 1990 1991 1992 1993 19% 1995 1996 1997 1998 1999 2000 2001 2002 2003 2006 2005 2006 an Un (ku) (ku) (ku) (ku) (ku) (kw) (ku) (ku) (ku) (kW) (kw) (ku) (ku) (ku) (ku) (ku) (ku) (kw) (ku) (ku) Skagway 0 0 0 0 0 0 0 0 ‘S00 0 0 0 0 = 2,500 0 0 0 0 865 0 Haines 0 0 0 0 0 0 0 0 2.670 0 0 0 Oo 1,600 0 0 0 0 0 0 Green’s Creek 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Juneau 285272 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Hoonah 1,220 0 0 0 0 0 0 0 0 1,220 0 0 0 0 a a 0 a 0 0 0 Kake 1,430 0 0 0 0 0 0 0 0 0 0 0 0 0 1,630 0 0 0 0 0 0 Sitka 7/500 0 0 0 0 0 0 0 0 0 0 0 0 0 a 0 0 0 0 0 Angoon 750 0 0 0 0 0 0 0 0 950 0 0 0 0 0 0 0 0 0 0 0 Tenatee 300 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Petersburg $600 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Urangel! 7,500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Ketchikan 17,450 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Quartz Hill 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Prince of Wales 6,905 0 0 0 0 1,375 0 0 O 1,400 3,030 = 1,100 0 0 0 0 0 0 0 0 0 Netlakata 6,950 0 0 0 0 0 0 0 a 0 0 0 0 0 0 0 0 a 0 0 0 Table 7-4 SYSTEM HYDRO GENERATION SOURCES Annual Average Plant Capacit Ener cD CHW Snettisham 46.0 216,000 Crater Lake 27.0 118,000 Tyee Lake 20.0 114,100 Swan Lake Zio) 85,400 Communities connected to a System Hydro Project were assumed to require 100% of the peak load as back-up diesel capacity. These diesel units would be necessary for emergency operation, for peaking requirements, for voltage regulation, or to meet remaining load requirements not available from the hydro projects. A minimum of 5% diesel generation is assumed in all communities. Communities not interconnected to System Hydro were assumed to require diesel capacity equal to 125%-130% of the peak load depending on the ratio of the largest diesel unit to the overall capacity requirements; i.e. smaller communities require a higher diesel reserve. Costs All costs are given in terms of 1987 dollars. The five sources of costs in this analysis are the transmission lines, local hydroelectric projects, System and Canadian hydroelectric projects, and diesel generation. The costs are busbar costs and do not include cost allowances for distribution, administration, and customer billings. Since these excluded costs are the same for all alternatives, the relative ranking of alternatives is not affected. Diesel Fuel Prices. Table 7-5 shows the diesel fuel price forecasts that were used in the analyses. The high and low forecast shown were furnished by the Power Authority. Because of the need to develop a reference case analysis reflecting the most likely assumptions, a mean diesel fuel price projection, the average of the high and low forecasts, was computed. 7-10) Table 7-5 OIL AND DIESEL FUEL PRICE FORECASTS High Forecast Low Forecast Mean Forecast oil Diesel oil Diesel oil Diesel Price Price Price Price Price Price Year ($/bb1) ($/gal) ($/bb1) ($/gal) ($/bb1) ($/gal) 1987 18.00 0.70 15.00 0.65 16.50 0.68 1988 18.63 0.72 1S. 0.66 16.97 0.69 1989 19.28 0.75 15.62 0.68 17.45 0.71 1990 19.96 0.78 15.94 0.69 17.95 0.73 1991 20.66 0.80 16.27 0.70 18.46 0.75 1992 21.38 0.83 16.60 0.72 18.99 0.78 19193 22513 0.86 16.94 0.73 19.54 0.80 1994 22.90 0.89 17.29 0.75 20.09 0.82 1995 23.70 0.92 17.64 0.76 20.67 0.84 1996 24.53 0.95 18.00 0.78 21.26 0.87 1997 25639 0.99 18.00 0.78 21.69 0.88 1998 26.28 1.02 18.00 0.78 22.14 0.90 1999 27.20 1.06 18.00 0.78 22.60 0.92 2000 28.15 1.09 18.00 0.78 23.07 0.94 2001 29.14 1.13 18.00 0.78 231157 0.96 2002 30.15 1.17 18.00 0.78 24.08 0.98 2003 31.21 1.21 18.00 0.78 24.60 1.00 2004 32.30 1.26 18.00 0.78 25:6 15 1.02 2005 33.43 1.30 18.00 0.78 25-71 1.04 2006 34.60 1335 18.00 0.78 26.30 1.06 To reflect differences in diesel fuel costs in the varous load centers a diesel fuel cost ratio was developed for each. Table 7-6 shows the diesel fuel cost ratio for each load center. A ratio of 1.10 indicates that the diesel price in that load center is 1.10 times the reference price given above. Diesel efficiency (kilowatt per gallon) and diesel O&M costs ($/kWh) are also indicated in Table 7-6 for each load center. These figures are based on information furnished by the Power Author- ity, or were assumed if information was unavailable. 7-11 Table 7-6 DIESEL COSTS Fuel Cost O&M Load Center Ratio Efficienc Costs ae SS TkWh/gal) «= (3/KWh) Skagway 1.03 13.40 0.05 Haines 17102 1625 0.05 Green's Creek 1.00 14.00 0.03 Juneau 1.00 11.00 0.02 Hoonah 1.24 11.20 0.05 Kake 1.26 11.45 0.05 Sitka 1325 12.00 0.03 Angoon 1.25 10.55 0.05 Tenakee 25 10.00 0.05 Petersburg 1.10 10.00 0.05 Wrangell 1.10 10.00 0.05 Ketchikan 1.00 14.00 0.03 Quartz Hill 1.00 14.00 0.03 Prince of Wales 1.00 12.20 0.04 Metlakatla 1.00 12.00 01.05 O&M Costs. Diesel operation and maintenance (0&M) costs are based on data provided by local utilities. Diesel O&M costs for each community are shown in Table 7-6. Hydro O&M costs are based on data supplied by each utility supplying hydroelectric power. When information was not avail- able, O&M costs were determined using formulas derived by arithmetic regressions of hydro O&M cost data. Table 7-7 gives the O&M costs for the System, Canadian and Local hydro plants. O&M costs for Canadian generation were assumed to be included in the energy price. Annual O&M costs for transmission lines were taken as one percent of the initial cost of the line, including substations and/or DC converter stations. Investment Costs. An investment cost of $300 per kW was assumed for diesel units. New diesel capacity was added, by increments of 500 kW, based on existing capacity, retirements, and minimum reserve criteria. System and Local Hydro investment costs for existing plants are assumed to be sunk costs and therefore excluded from this study. Transmission line construction costs are shown on Table 7-8. The costs shown on the table include land and land rights, right-of-way clearing, overhead line and/or submarine cable Te 12 materials and installation costs, and substation/converter station costs for each interconnection. A contingency allowance of 20% is included, as is an allowance of 17.5% for engineering and owner's costs. Hydro Energy Costs. Table 7-7 shows the installed cap- acity, average annual energy, and energy costs of the hydroelec- tric projects. For the purpose of the economic analysis, no debt repayment for the existing local and S.E. hydro were included, since, from the standpoint of all Southeast Alaska, these costs would be similar for the Base Case and all alterna- tive scenarios. As a result, no energy costs were included for the local and S.E. hydro projects. These costs, and the vari- ous tariffs for the S.E. hydro projects, can only be thoroughly addressed in a detailed analysis of the financial feasibility of the selected alternatives. Including these sunk costs in such an analysis, while not affecting the overall results of the study, would alter the benefits of new transmission lines for individual load centers. Petersburg and Wrangell, for example, would benefit from a Tyee-Swan Lake interconnection because the sunk cost of Tyee would be shared among three load centers instead of the present two. Energy prices of B.C. Hydro and N.C.P.C. Hydro generation were are assumed to be $0.055 per kilowatt-hour (including both power and energy charges and the cost of the required Candadian transmission facilities). A sensitivity analysis was performed using $0.07 per kilowatt-hour. 3 Table 7-7 HYDROELECTRIC PROJECT DATA Installed Project Capacit ea SYSTEM HYDRO PROJECTS Snettisham 46,000 Swan Lake 22,500 Tyee Lake 20,000 Crater Lake 27,000 CANADIAN HYDRO PROJECTS British Colombia 100,000 Whitehorse 22,000 LOCAL HYDRO PROJECTS Skagway 1,000 Haines 0 Green's Creek 0 Juneau 10,600 Hoonah 0 Kake 0 Sitka 26,540 Angoon 0 Tenakee 0 Sealaska 0 Petersburg 2,000 Wrangell 0 Ketchikan 14,000 Quartz Hill 0 Prince of Wales Is. 0 Metlakatla 4,000** Average Annual Ener (MWh7yr) 216,000 85,400 114,000 118,000 Unlimited 100,000 2940 0 0 60,000 0 0 103,000 0 0 0 10,000 0 62,700 0 0 22, 150** Energy Price ($7MWh) oooo 55 55 oooooocoo°co°o°coe oo oo Annual O&M Costs ($*1000) 598* 297" S2n= 349* oo 40* 74* 0 23x 0 0 200** *The indicated O&M costs were calculated using the following x (1112 x CAP + 142 x AEP) x 1.46 rated capacity (MW) formula: Normal Annual O&M = 18999,3804 CAP Where CAP = and AEP = average annual energy production (GWh) **Includes planned Chester Lake Hydroelectric Project. 7-14 Table 7-8 INTERTIE CONSTRUCTION COSTS Connection Voltage Cost (kv) ($*7000) From Juneau to Skagway and Haines Juneau-Skagway 138 47,280 Juneau-Skagway-Haines 34.5/138 54,030 From Whitehorse to Skagway and Haines Whitehorse-Skagway (U.S. Facilities only) 138 7,420 Skagway-Haines 34.5 13,240 From Juneau to Sitka Juneau-Green's Creek 34.5 11,220 Juneau-Green's Creek 69 19,490 Green's Creek-Hoonah 69 23,240 Hoonah-Tenakee Springs 69 8,190 Tenakee Springs-Angoon 69 23,790 Tenakee Springs-Sitka 69 31,040 Tenakee/Sitka-Angoon 69 20,680 From Juneau to Petersburg Juneau-Green's Creek 138 25,750 Green's Creek-Hoonah 138 31,250 Hoonah-Tenakee Springs 138 12,610 Tenakee Springs-Sitka 138 43,710 Tenakee/Sitka (138 kV)-Angoon 69 23,280 Sitka-Kake : 100(DC) 51,980 Kake-Petersburg 138 26,450 From Tyee to Sitka Petersburg-Kake (without Kake- Snettisham) 138 27,440 Kake-Sitka 100(DC) 48,220 From Juneau to Sitka Snettisham-Kake 100(DC) 57,990 Kake-Sitka 100(DC) 34,230 From Petersburg to Sitka followed by Snettisham-Kake Petersburg-Kake 138 27,440 Kake-Sitka 100(DC) 48,220 Snettisham-Kake 100(DC) 41,120 1=15 mm’ Table 7-8 (Cont'd) INTERTIE CONSTRUCTION COSTS Connection Voltage Cost (kv) ($*7000) From Snettisham to Sitka followed by Petersburg-Kake Snettisham-Kake 100(DC) 57,990 Kake-Sitka 100(DC) 34,230 Kake-Petersburg 138 26,450 From Tyee Lake to Swan Lake (with Prince of Wales Is.) Tyee Lake-Swan Lake 138 28,900 Ketchikan-Prince of Wales Is. 75(DC) 43,460 Prince of Wales Is. System 69 9,360 Ketchikan-Metlakatla (from Bailey) 69 11,210 Ketchikan-Metlakatla (from Mt. Pt.) 34.5 6,610 From Tyee Lake to Ketchikan (with Prince of Wales Is.) Tyee Lake-Ketchikan 138 50,270 Tyee/Ketchikan-Prince of Wales Is. 69 22,150 Prince of Wales Is. System 69 9,360 Swan Lake-Quartz Hill 138 45,660 From Tyee Lake to Swan Lake followed by Swan Lake to Quartz Hill Tyee Lake-Swan Lake 138 28,900 Swan Lake-Quartz Hill 138 38,800 From Tyee Lake to Swan Lake and Quartz Hill to B.C. followed by Swan Lake to Quartz Hill Tyee Lake-Swan Lake 138 28,900 Quartz Hill-B.C. 100(DC) 39,290 Swan Lake-Quartz Hill (U.S. facili- ties only) 138 38,140 Methodology Screening Method Because of the multitude of possible intertie alternatives, a screening analysis was performed to identify the most economi- cally favorable alternatives, and to form the basis for the development of the alternatives used in the detailed study. To avoid eliminating potentially feasibile alternatives during the 7-16 System, two alternative routes were considered for the Tyee- Ketchikan interconnection; one is to link Tyee directly to Ketchikan via Cleveland Peninsula and the other is to link Tyee to Ketchikan via a Tyee-Swan Lake interconnection. Total S.E. System Intertie alternatives refer to the potential inclusion of all load centers in the system. Two main routes were considered for interconnecting the Northern, Central and Southern systems. The "East Route" refers to an interconnection of the three geographic subsystems via a Snettisham-Kake- Petersburg line and Tyee-Swan Lake. The "West Route" would entail interconnecting the three subsystems via Juneau-Hoonah, Sitka, Kake and Peters- burg, and the Tyee-Swan Lake line. Alternative III - Power Supplied by N.C.P.C. Alternative III involves the all S.E. Alaska system, described in Alternative II, with an interconnection to the Northern Canada Power Commission (N.C.P.C.) grid at Whitehorse via Skagway. See Figure 7-5. Power to the Northern System and an entire S.E. Alaska grid, with their variations, were investi- gated. Alternative IV - Power Supplied by B.C. Hydro Alternative IV involves the all S.E. Alaska system, described in Alternative II, with an interconnection to Canadian generation sources in British Columbia via transmission lines from Kitsault, B.C. to Quartz Hill Mine and from Quartz Hill to the Swan Lake Project. See Figure 7-6. Power to the Southern System and an entire S.E. Alaska grid, with their variations, were analyzed. Alternative V - Power Supplied by Both B.C. Hydro and N.C.P.C. As indicated, power would be furnished from both the north and the south in Alternative V. Cases involving split grids, with each Canadian utility serving selected Alaska load centers, were analyzed, as well as an interconnection of the two Canadian utilities through Alaska. See Figure 7-7. The appropriate variations were analyzed. Criteria for Economic Evaluation The economic parameters and assumptions used in the evalua- tion of the various alternatives are based on guidelines sup- plied by the Alaska Power Authority and local utilities. The economic parameters detailed below are summarized on Table 7-2. 7 Table 7-9 SCREENING ANALYSIS ENERGY ALLOCATION AND COSTS Year 2006 Local Minimum Replaceable Elec. CPW. Load Hydro Snettisham Crater Tyee ‘Swan Diesel Diesel Price R. Diesel Load Center (MWh) (MWh) (MWh) (Mwh) (MWh) (MWh) (MWh ) (MWh) ($/kwh) ($*1000) Skagway 6,500 2,940 325 3,235 $0.098 3,879 Haines 10,200 510 9,690 $0.098 11,540 Green's Creek 26,061 1,303 24,758 $0.096 17,623 Juneau 272,400 60,000 216,000 118,000 13,620 (135,220)1/ $0.096 NA Hoonah 5,887 294 5,593 $0.112 7,655 Kake 3,500 175 3,325 $0.114 4,605 Sitka 146,100 103,000 7,305 35,795 $0.113 49,287 Angoon 3,116 156 2,960 $0.113 4,076 Tenakee Springs 451 23 428 $0.113 590 Petersburg 37,600 10,000 57,050 1,880 (31,330)1/ $0.103 NA Wrangell 24,800 57,050 1,240 (33,490)1/ $0.103 NA Ketchikan 191,800 62,700 85,400 9,590 34,110 $0.096 40,070 Quartz Hill 250,300 12,515 237,785 $0.096 279,336 Prince of Wales 23,280 a 1,164 22,116 $0.096 25,981 Metlakatla 24,600 22,150 1,230 1,220 $0.096 1,433 1 Numbers in parenthesis indicate a surplus of hydro generation in the corresponding load centers. NA: Not Applicable because excess hydro energy is available at these load centers. Results of the Screening Table 7-10 summarizes the results of the screening analy- sis. The analysis was performed on an incremental basis by progressively interconnecting load centers to a source of sur- plus hydro power to utilize the available hydro generation. (Based on the load forecast for the year 2006, surplus hydro generation will be available from both the Snettisham-Crater Lake and Tyee Lake projects). The analysis was also performed for the geographic subsystems and for the entire Southeast Alaska System. The results for the screening analysis are given in the following paragraphs. Northern System. As shown in Table 7-10, an intertie of Snettisham to Skagway and Haines via Juneau is not a favorable alternative. The B/C ratio of a Juneau-Skagway-Haines line is 0.44. The Juneau-Green's Creek connection appears to be a viable alternative with a B/C ratio of 2.67 when a 34.5 kV transmission line was used. Because Green's Creek mine has an expected life of only 20 years this load center was treated differently than the others in that costs and energy requirements were assumed to extend for only 20 years instead of the 50-year assumption used for analysis of all other load centers. When a 69 kV transmission line was used for the Juneau- Green's Creek connection, the B/C ratio dropped to 1.53. With the addition of Hoonah to Juneau-Green's Creek the B/C ratio of the entire interconnection drops to 0.93 because the incremental B/C ratio of the Green's Creek-Hoonah segment is only 0.37. The overall B/C ratio continues to decrease when Tenakee and Angoon are included in the system. However, if the line is extended at 69 kv from Tenakee to Sitka (West Route), without Angoon, the overall B/C ratio increases to 1.43 because the increment of Tenakee-Sitka has a B/C ratio of 2.47. The B/C ratio for the Angoon transmission segment is 0.27. The other way to connect Sitka to Snettisham-Crater Lake power is the East Route, via the Snettisham-Kake-Sitka intercon- nection using 100 kV DC cables. This alternative has a B/C ratio of 0.91. It is not economically attractive. As a result of this analysis, the Juneau-Green's Creek interconnection and the West Route to Sitka appear to be the only two attractive interconnections in the Norhtern System. Central System. The second source of surplus S.E. hydro- electric energy in 2006 is the Tyee Lake Project. An intertie of Petersburg to Kake is not attractive, having a B/C ratio of 7-18 TABLE 7-10 SCREENING ANALYSIS RESULTS MEDIUM LOAD FORECAST S.E. CANADA DIESEL CANADA DIESEL. = ANNUAL ANNUAL REPLACEABL HYDRO HYDRO ENERGY ENERGY ENERGY —ENERGY OBM ENERGY AVAILABLE AVAILABLE NEEDED PRICE PRICE costs COSTS INTERTIE EXPANSION PLANS (Mh) (Mh) (Hh) (Mh) ($/kWh) —($/kWh) = ($1000) ($1000) wane crn enencenncemnenenneannn enema nnnnnnnnnnnan nen nnnnnnnnnnnnnnennns MM MMM 1]. A. NORTHERN SYSTEM (Supplied by Snett and Crater) 1, Juneau-Skagway 3,235 135,220 0 0 0.095 0.0% 0 472.8 2. Suneau-Haines-Skagway 12,925 135,220 0 0 0.055 0.0% Q 940.3 3. Juneau-Greens Creek (34 kVs20 year lite) 245758 = 1355220 0 0 0.055 0.096 0 112.2 4. Suneau-Greens Creek (69 kV» 20 year lite) 26,758 135220 0 Q 0.055 0.0% 0 196.9 5. Juneau-Greens Creek-Hoonah 3351 1355220 0 0 0.055 (0.0% 0 = 427.3 6. Juneau-Greens Creek-Hoonah-Tenakee 30,779 135,220 0 a 0.055 0.096 a $09.2 7. Juneau-Greens Creek-Hoonah-Tenakee-Angoon 33,739 135,220 0 0 0.055 0.09 0 147.1 8. Juneau-Greens Creek-Haanah-Tenakee-Si tka 66:57 = 1355220 0 Q 0.055 0.0% a 619.6 9. Juneau-Greens Creek-Hoonah-Tenakee-Sitka» Angoon 69,536 135,220 0 0 0.055 0.0% 0 1,026.6 10. Snettishas-Kake-Sitka 39,120 135,220 0 0 0.055 0.0% Q 22.2 B. CENTRAL SYSTEM (Supplied by Tyee) 1, Petersburs-Kake 35325 64s 820 0 0 0.055 0.096 0 276.4 2. Petersburg-Kake-Sitka 39120 64,820 q 0 0.055 0.0% a 756.6 C. SOUTHERN SYSTEM (Supplied by Tyee and Swan) 1. TYEE-KETCHIKAN a. Direct Connection 3or110 64,820 0 0 0.055 0.09 0 502.7 b. Connected via Swan Lake Yi10 64,820 0 Q 0.055 0.0% a 269.0 2. TYEE-KETCHIKAN-PRINCE OF WALES a. Direct Connections from Tvee $6226 64820 0 0 0.055 0.096 0 617.6 b. Connected via Swan Lake and Ketchikan-Prince of Wales 961226 64,820 0 O 0.055 0.0% Oo 609.8 J. Tyee-Swan plus a. Ketchikan-Metlakatla (69kV trom Bailey) 35,330 645820 0 0 0.055 0.0% 0 401.1 b. Ketchikan-Metlakatla (via Nt Pt 34.5 kV) 35,330 64,620 0 0 0.085 0.0% 0 355.1 c. Petersbura~Kake-Sitka 73:230 645820 0 = 410 0.055 = 0.09 B10 1,065.6 d. Swan Lake-Quartz Hill 271,695 64,820 0 207,075 0.055 0.09% 19,938 677.0 D. NORTH SOUTH INTERCONNECTIONS WITH QUARTZ HILL 1. (East Route) Juneau-Green’s Creek» Snetthishae- Kake-Petersburg, Tyee-Swan-Quartz Hill, Ketchikan-Prince of Wales 322,094 + 200,040 0 122,056 0.055 0.0% 11,752 2,153.6 2. Same as above plus Kake-Sitka 357,689 = 200,040 Q 157,869 = 0.055 0.096 = 154197 2,496.7 3. Snett-Kake-Petersburg» Tyee-Swan-Quartz Hi! 2755220 200,080 O 75,180 = =—0.055 0.0% = 75239 1,521.4 4. (West Route) Juneau-Green’s Creek-Haonah-Tenakee- Angoon-Sitka-Kake-Petersburg» Swan-Tyee-Quartz Hill» Ketchikan-Prince of Vales 341,794 200,060 O 141,756 0.055 0.0% 13,669 3,348.1 €. NORTH SOUTH INTERCONNECTIONS WITHOUT QUARTZ HILL 1. (East Route) Juneau-Green’s Creek» Snetthishae- Kake-Petersburg, Tyee-Swans Ketchikan-Prince of Vales 64,309 200,060 0 0 0.055 0.09 O 1,766.4 2. Same as above plus Kake-Sitka 120,106 200,060 a a 0.085 0.0% Q 2,108.7 J. (West Route) Juneau-Green’s Creek-Hoonah-Tenakee- Angoon-Sitka-Kake-Petersburq: Tvee-Swans Ketchikan-Prince of Wales 126+125 200,040 0 0 0.055 0.09% O 2,960.1 TRANS COST (#1000) SHOU 47,280 94,030 41,220 19,490 42,730 $0,920 76710 81,960 102,640 921220 27,440 751660 505270 26,900 61,780 60,960 405110 35,510 106,560 67,700 2155360 269,670 1525140 334,810 176»640 2105670 296,010 C.P.U. ENERGY ($#1000) 0000000 0 0 0 0 0 0 0 0 0 a eo 0 a 9,880 2635259 143,382 185,432 885317 1661526 C.P.U. 08M ($#1000) JUO UO 51768 61592 829 1,6ht 213 6213 WMS 10,000 12,523 11,251 3,348 W231 * 6133 35526 95978 9,880 4,894 4,332 12,757 85260 26s275 30,461 18,562 40,849 21,591 25727 3osi15 C.P.u. TRANS ($1000) SHOE 265593 28,106 51836 10,138 22522 261486 381861 421632 $3538? 475969 145273 395385 261148 15,032 42,538 425122 20,863 18,471 541387 35,215 112,021 129,867 195136 1761153 91,880 109,685 153,971 cab we TOTAL INTERTIE (#1000) JHU 301361 341696 61666 11,579 27,460 32,699 47,976 521632 655911 $9,220 17,621 48,586 32,281 18,558 $2516 52,002 25,757 22,803 775026 2865736 2815678 345,760 186,015 3815526 113,431 135,413 190086 PAGE 1 OF 2 C.P.U. REPLACEABLE OIESEL B/C ($*1000) RATIO JURONOHE UJQUH06E 3879 0.13 15,419 0.46 17,623 2.64 17,623 1.82 25,278 0.92 25,868 0.79 295944 0.62 75:155 1.43 795231 1.20 $3,692 0.91 4,605 26 93,892 1.1 40,070 1.54 40,070 2.78 66,051 Li 66,051 1a 41,504 1.61 41,506 1.62 935962 ize 3195406 Lit 3675615 1H 416,902 1.21 326,011 1.74 3995167 1.05 88,279 0.78 1375566 1.02 145,811 0.77 PAGE 2 OF 2 TABLE 7-10 SCREENING ANALYSIS RESULTS MEDIUM LOAD FORECAST S.E. CANADA DIESEL CANADA = DIESEL = ANNUAL ANNUAL CPU. (C.P.U. REPLACEABL HYDRO HYDRO ENERGY ENERGY ENERGY — ENERGY O8n TRANS = CPU. CPU OCP TOTAL REPLACEABLE ENERGY AVAILABLE AVAILABLE NEEDED PRICE PRICE COSTS COSTS COST ENERGY O&M TRANS —INTERTIE = OLESEL a/c INTERTIE EXPANSION PLANS (Muh) (MWh) (Nh) (Hah) ($/kWh)—($/kUh) ($1000) ($4100) ($*1000) ($#1000) (#1000) ($*1000) ($*1000) ($*1000) RATIO JUHHHUUHE JHHSHHBOE JSG SNSSGNQ6 JHSUSHH06 JNHESBINE INSGON006 JBHUQHHE BOG9Q006 IQUHBQ006 JOQUGQOESQQOUO06 SGGGGGE SB BQUGgE JIG G QUE J1}. A. POWER SUPPLIED BY N.C.P.C. -~ NORTHERN SYSTEM 1. Whitehorse-Skagway-Haines 12,925 0 100,000 0 0.055 0.096 71 206.6 20,660 6,673 2521 10,746 = 21,940 15,419 0.70 2. Uhiteharse-Skagvay-Haines-Juneau-Green's Creek- Hoonah-Tenakee-Angoon 46,666 135,220 100,000 0 0.055 0.0% O 1,362.6 1345260 D 16,380 69,836 = Bs217 45,343 0.53 3. Sase as abave plus Tenakee-Sitka 82,459 1355220 100,000 Q 0.055 0.0% QO 1621.9 162,190 O 19,788 = 84366 = 104,152 74650 0.91 IV. A, POWER SUPPLIED BY B.C. HYDRO -- SOUTHERN SYSTEM 1. B.C:-Quartz Hill (US facilities only) 2375785 0 1,000,000 0 0.055 0.0% 13,078 392.9 39,290 159,561 4,7% = 20,437 184,792 2791336 1.51 2. B.C.-Quartz Hill-Swan (US facilities only) 271,895 0 1,000,000 O 0.055 0.096 = 16,956 = 835.2 83,520 182,450 101904344643 236,083 319,406 1.35 3. B.C.-Quartz Hill-Swan-Tyee (US facilities only) 271,895 64,820 1,000,000 0 0.055 0.076 = 11,389 1,071.7 107170 138,958 = 13,075 = 955745 = 2075778 == 319406 1,54 4. B.C.-Quartz Hill-Swan-Tyees Petersburg-Kake- Sitka (US facilities only) 311,015 64820 1,000,000 D 0.055 = 0.096 = 13,541 1,828.3 182,830 165,205 22,306 = 75100» 282,611 373298 1.32 y. POWER SUPPLIED BY BOTH BC HYORO AND N.C.P.C. ‘A. ONLY QUARTZ HILL RECEIVES POWER FROM B.C. HYDRO 1. B.C.-Quartz Hill, Uhitehorse-Skagway-Haines 2505710 0 337,785 0 0.055 0.0% = 13,789 607.9 = 60790» 1685234 W417 315620 2075271 2945755 1.42 2. B8.C.-Quartz Hills Whitehorse-Skagway-Juneau-Green’s Creek-Hoonah-Tenakee-Sitka 307)5% 0 337,785 0 0.055 0.0% = 16,918 1,745.2 174520 206,405 = 215292 90778 = 318475 = 358,370 113 3. Same as abave plus Haines and Angoon 3205244 0 337,785 0 0.055 0.09% = 175613 2,023.3 202,330 214,896 = 2468S 105,243 3441823 373,985 1.08 4. Whitehorse to Prince of Wales (West Route) Sane as V.A.2 above plus Lynn Creek-Haines, Sitka-Kake-Petersburgs Tyee-Swans Ketchikan-Prince of Vales 3675145 200,040 337,785 0 0.055 0.0% 9191 3,650.0 365,000 112,133 441532 189,857 3461522 440,566 1.27 S. Whitehorse to Prince of Wales (East Route) Sase as V.A.1 above plus Haines-Juneau-Green’s Creeks Snettishan- Kake-Sitkay Kake-Petersburg, Tyee-Swans Ketchikan- Prince of Vales 370,814 200,060 337,785 0 0.055 0.096 = 9393 -2985.3 298/530 114,575 36422 1551282 3065277 432,320 1.41 B. BC HYDRO AND NCPC HYDRO ARE INTERCONNECTED 1. (East Route) without Sitka Whi tehorse-Skagway-Juneau-Green’s Creek, Snettishaa- Kake-Petersburg» Tyee-Swan-Quartz Hill-B.C. 303,213 200,040 1,100,000 0 0.055 0.096 5675 2,586.3 258630 69,232 = 31530134424 = 235,186 = 3455513 1.47 2. (East Route) with Sitka = Sane as above plus Kake-Sitka 337,008 200,040 1,100,000 0 0.055 0.096 75663 25926.6 292,660 = 935252 -35)706 = 1525227 281,187 374,800 1.40 3. (West Route) Whitehorse-Skagway-Juneau-Green’s Creek- Hoonah-Tenakee-Sitka-Kake-Petersburg» Tyee-Swan- Quartz Hill-B.C. 345,029 200,060 1,100,000 0 0.055 0.096 797% = -3y513.5 351,350 = 9752972 = 42,867 = 182757 322,916 += -4035045 1.25 0.26. But since the year 2006 Sitka load demand is large, the Petersburg-Kake-Sitka interconnection warrants further study with a B/C ratio of 1.11. Southern System. Ketchikan's energy demand is large enough to absorb all available Swan Lake Project generation by year 2006 and warrant a connection to Tyee. As described in Chapter 6, two ways of connecting Ketchikan to Tyee were considered. The connection via Swan Lake was preferred to a direct Ketchikan-Tyee line. Their B/C ratios were 2.78 and 1.54 respectively. In addition, additional hydro energy from Tyee would be available for Prince of Wales Island, Metlakatla, Kake- Sitka, or Quartz Hill. The results of analyses of these inter- connections are shown below. : When Prince of Wales Island 1/ is added to the two Tyee- Ketchikan intertie alternatives, the interconnection via Swan Lake intertie shows a slight advantage. However, the incremen- tal B/C ratio of the Prince of Wales Island intertie from Ketchikan is only 0.95. On the other hand, if the direct con- nection from Tyee to Ketchikan via Cleveland Penninsula is con- structed (at a cost of approximately $50 million versus $29 million for the Tyee-Swan Lake intertie), the incremental B/C ratio for the addition of Prince of Wales Island would be 1.39 under the medium load forecast. The analysis assumes that the entire cost of Tyee-Ketchikan direct connection is allocated to Ketchikan. The transmission line, routed over Cleveland Penninsula, both facilities a relatively inexpensive connection to Prince of Wales Island but also increases the reliability of the Ketchikan power system by providing a separate link to a major power source. The incremental cost of about $11 million for the Cleveland Penninsula route versus the Tyee-Swan Lake line represents a cost to Ketchikan for increased reliability. Resolution of this question, Cleveland Penninsula route versus Tyee-Swan Lake, requires a detailed financial analysis, and is should be the subject of a future study. For the detailed eco- nomic analysis presented herein, the connection of Tyee to Ketchikan via Swan Lake is selected because it is the least cost alternative for the major load center at Ketchikan. V/ The costs used in the analysis include the $9,360,000 esti- mated cost of a 69 kV transmission system serving Thorne Bay, Hydaburg and intertied Craing/Klawock, based on the estimates presented in Black Bear Lake Hydroelectric Project Feasibility Report Update, Harza Engineering Company, February 1987. 7=19 An analysis of incremental costs and benefits was done for adding Metlakatla to the Tyee-Ketchikan system. The Metlakatla interconnection is not favorable. It has an incremental B/C ratio of 0.34 using the least cost transmission configuration, the 34.5 kV line from Mt. Point. The interconnection of Swan Lake and Tyee Lake to Kake and Sitka is not feasible, with an incremental B/C ratio of 0.92. For the connection of Quartz Hill Mine to Swan Lake and Tyee Lake, the B/C ratio is marginally feasible with a B/C ratio of 1.11 and an incremental B/C rato of 1.04. This is because the surplus energy available to Quartz Hill from Tyee would be only 30,710 MWh with this interconnection. With the addition of both Prince of Wales Island and Quartz Hill to a Tyee-Ketchikan sys- tem even less hydro energy would be available to Quartz Hill and the B/C ratio is only 1.00. In summary, for the Southern System, the Tyee-Swan Lake interconnection to meet the additional demand in Ketchikan has the most attractive B/C ratio of 2.78. The incremental addition of Prince of Wales or Meltakatla is not economically feasible, and the addition of Quartz Hill is only marginally feasible. Total S.E. Alaska Interconnection. Economic screening of an all Southeast Alaska interconnection resulted in a B/C ratio of 1.74 for the interconnection of Snettisham through Quartz Hill via the East Route. The West Route B/C ratio is 1.06. The East Route is, therefore, the most economically attractive of the two. Without Quartz Hill, the East Route is also the most attractive alternative, with a B/C ratio of 1.06. Power Supplied by N.C.P.C. Since the Local and S.E. Sys- tem Hydro energy available exceeds the 2006 load demand for all S.E. load centers except Quartz Hill, the only practical alter- native involving N.C.P.C. power would be Whitehorse-Skagway- Haines intertie, because the intertie from Snettisham-Juneau- Skagway-Haines was not found economically feasible. The Whitehorse-Skagway-Haines interconnection is not favorable, having a B/C ratio of 0.70. Power Supplied from B.C Hydro. For the same reasons given in the discussion of N.C.P.C. above, the only practical B.C. Hydro alternative is an intertie to Quartz Hill. This alterna- tive has a B/C ratio of 1.51. An intertie to Swan-Tyee- Petersburg-Kake-Sitka was also analyzed to examine the economic feasibility of connecting the large demand in Sitka to B.C. Hydro. However, the incremental B/C ratio of this intertie is less than 1.0. 7-20 Power Supplied from Both N.C.P.C. and B.C. Hydro. As stated above, the only attractive alternative is the intertie B.C. Hydro to Quarz Hill. Summary. Based on the data presented above, four intertie expansion plans were developed for more detailed analysis. The four expansion plans combine the intertie alternatives having the most favorable B/C ratios, while also taking into account utilization of surplus energy to supply to the areas greatest in need. The four expansion plans are as follows: Intertie Expansion Plan A. Shown on Figure 7-8, Expansion Plan A includes the following interconnections: Juneau-Green's Creek Tyee Lake-Swan Lake B.C. Hydro-Quartz Hill Intertie Expansion Plan B. Shown on Figure 7-9, Expansion Plan B includes: Juneau-Green's Creek-Hoonah-Tenakee-Sitka Tyee Lake-Swan Lake B.C. Hydro-Quartz Hill Intertie Expansion Plan C. Shown on Figure 7-10, Expansion Plan C has the following interconnections: Juneau-Green's Creek Snettisham-Kake-Petersburg Tyee Lake-Swan Lake-Quartz Hill Intertie Expansion Plan D. Shown on Figure 7-11, Expansion Plan D has the following interconnections: Juneau-Green's Creek Petersburg-Kake-Sitka B.C. Hydro-Quartz Hill Detailed Analysis General. Expansion Plans A, B, C and D were analyzed in further detail based on the economic criteria previously des- cribed. Using the medium load forecast, the mean fuel cost scenario, and a 3.5% discount rate, annual costs for the period 1987-2006 were calculated. Annual costs for the period 2007 to 2034 were held constant at 2006 level. The analysis was performed using two personal computer spreadsheet programs. The first program allocates the S.E. System and Canadian hydropower to each load center based on each a2 FIGURE 7-8 . WHITEHORSE — O SKAGWAY & ee Avan um Lo HAINES @ : 7 52 JUNEAU GREENS CREEK HOONAH * SNETTISHAM- CRATER LAKE TENAKEE SPRINGS @ aNcoon PETERSBURG PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS e@ GENERATION SOURCES KETCHIKAN EXISTING T/LINE PROPOSED T/LINE @ QUARTZ VOLTAGE METLAKATLA COST(MILLIONS) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN A HARZA ENGINEERING COMPANY OCTOBE= 1987 FIGURE 7-9 . WHITEHORSE ~. O SKAGWAY 2 —— HAINES @ $19.69 HOONAH GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS @ ancoon e@ PETERSBURG WRANGELL &. % z TYEE LAKE PRINCE LEGEND: OF WALES ISLAND @ - Loao centers @ O GENERATION SOURCES SG — ’ KET 2 EXISTING T/LINE CHIKAN s00kVv DC (BIPOLAR). 3 PROPOSED T/LINE e@ QUARTZ 9 38KV VOLTAGE METLAKATLA 41> $ COST(MILLIONS) — kITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN B HARZA ENGINEERING COMPANY OcTOeses 1987 FIGURE 7-10 . WHITEHORSE ee O SKAGWAY & ie HAINES @ HoonaH @ GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS @ ancoon PETERSBURG TYEE LAKE PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS e GENERATION SOURCES EXISTING T/LINE PROPOSED T/LINE VOLTAGE COST(MILLIONS) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN C HARZA ENGINEERING COMPANY FIGURE 7-11 is WHITEHORSE > SKAGWAY @& lian O an, Og N. ite Ao, a HAINES @ GREENS CREEK SNETTISHAM- CRATER LAKE TENAKEE SPRINGS @ ancoon PETERSBURG TYEE LAKE PRINCE LEGEND: OF WALES ISLAND SWAN @ - Lodo centers e 415k LAKE CO - GENERATION SouRCES KETCHIKAN wees - EXISTING T/LINE 100KV DC (BIPOLAR). === - PROPOSED T/LINE @ QUARTZ METLAKATLA KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY EXPANSION PLAN D HARZA ENGINEERING COMPANY specific expansion plan. The second program uses the capacities and energies supplied to each load center by each power source to determine the corresponding capital, operation and mainte- nance, and energy costs. The present worth of each total annual cost is calculated, and then added to the cumulative present worth. The cumulative present worth calculated for each commun- ity for the years 1987-2034 are used in the Benefit cost ratios for alternative comparison. The benefits and costs attributable to the three expansion plans were further refined by the addition of estimated communi- cation system costs for new or upgraded communications facili- ties required for each expansion plan. Table 7-11 shows the estimate costs of the communication facilities. An estimate of the transmission system losses attributable to each expansion was also included in the detailed analysis of the plans. Table 7-12 is a tabulation of losses for each of the expansion plans. The information in the table gives the estimated energy losses for each category of loss, and the estimated total annual losses. For analysis of the three expansion plans, these losses were taken into account by reducing the amount of energy generation assumed to be available from System Hydro plants or, in the case of Quartz Hill connected to B.C. Hydro, by assuming an equivalent increase in load center demand. Energy Allocation Procedure. To meet the annual energy requirements in each load center, the following procedure was used: 1. All Local hydro energy sources available at a load center are assumed to be utilized first. 26 To meet hydropower and transmission outages, peaking requirements and voltage regulation needs, a 5% mini- mum diesel energy generation is assumed for each load center. ae If a load center is intertied to System Hydropower project(s), the hydro energy available is used to meet the load center's energy demand not met by Nos. 1 and 2 above. The hydro energy available from System proj- ect(s) was assumed to be be shared between all load centers connected with the project(s) in proportion to their unfulfilled energy requirements. For cost allocation purposes, transmission and O&M costs were assumed to be shared in proportion to the energy delivered in each load center. For example, if Snettisham is intertied to Juneau, Greens Creek, Hoonah, Tenakee and Sitka, the energy available from Snettisham and all associated costs would be shared 7-22 Table 7-11 ESTIMATED COMMUNICATION SYSTEMS COSTS Estimated Costs In $Millionsl/ Route Segment Plan A Plan B Plan C Plan D Snettisham-Juneau2/ - - - e Juneau-Green's Creek $ -3/ $0.2 s -3/ s -3/ Green's Creek-Hoonah NA 0.2 NA NA Hoonah-Tenakee Springs NA 0.2 NA NA Tenakee Springs-Sitka NA 0.2 NA NA Snettisham-Kake NA NA 250 NA Kake-Sitka NA NA NA 2.0 Kake-Petersburg NA NA Que 0.2 Peterburg-Wrangell-Tyee2/ = c 0.4 0.4 Tyee-Swan Lake Oz Oe 0.2 NA Swan Lake-Ketchikan2/ - - = ml Swan Lake-Quartz Hill NA NA -3/ NA Quartz Hill-Kitsault, B.c.4/ _2.0 2.0 NA 2.0 Total Estimated Cost 2.2 3.0 3.3 4.6 (January 1987 price level) 1/ Costs based on estimated communication system costs presented in "Southeast Alaska Intertie DC Transmission System," Teshmont Consultants, Inc. November 1982. 2/ Existing system assumed adequate, or upgraded as indicated. 3/ Cost of assumed leased telephone communications system included in O&M costs. 4/ U.S. facilities only. Table 7-12 SUMMARY OF ANNUAL SYSTEM LOSSES FOR EXPANSION PLANS A, B, C, AND pl/ (In MWh per Year) AC Dc AC Cable Dc Total System Cable Dielectric Convertor System Expansion Plan Losses Losses Losses Losses Losses Plan A - North 1,330 0 640 0 1,970 Plan A - South 1,025 0 2,616 2,3082/ 5,949 Total Plan A 2,355 0 3,256 2,308 7,919 Plan B - North 1,317 0 1,253 0 2,570 Plan B - South 1,056 0 2,478 2,3082/ 5,848 Total Plan B_ 2,373 0 3,731 2,308 8,412 Plan C 2,780 271 4,263 1,154 8,468 Plan D - North 1,330 0 640 0 1,970 Plan D - Central 323 74 2,527 1,154 4,078 Plan D - South 312 0 0 2,308 2,620 Total Plan D 1,965 74 3,167 3,462 8,668 1/ Medium load forecast, year 2006 demand. 2/ Quartz Hill-Kitsault losses of 2,308 MWh/year are for U.S. converter station only. among these five load centers, in proportion to each load center's Snettishan energy use. 4. If a load center was assumed intertied to a Canadian generation source, the Canadian energy was used to meet the energy demand not met by Nos. 1, 2, and 3 above. As in No. 3, the Canadian energy available and the associated costs were shared among all load cen- ters intertied to Canadian generation. Bie If the annual energy requirement of the load center is not met by Nos. 1, 2, 3, and 4 above, then additional diesel generation was assumed to be required. An example of the results of the energy allocation for Expansion Plan C, year 2006 medium load forecast, is shown in Table 7-13. 7-23 Table 7-13 ENERGY ALLOCATION YEAR 2006 - EXPANSION PLAN C Diesel Energy Local Gener- S.E. Canadian Skagway 6,500 2,940 3,560 0 0 Haines 10,200 0 10,200 0 0 Green's Creek 26,061 0 5,540 20,521 0 Juneau 272,400 60,000 47,639 164,761 0 Hoonah 5,887 0 5,887 0 0 Kake 3,500 0 744 2,756 0 Sitka 146,100 103,000 43,100 0 0 Angoon 3,116 0 3,116 0 0 Tenakee Springs 451 0 451 0 0 Petersburg 37,600 10,000 6,282 21,318 0 Wrangell 24,800 . 0 5,202 19,528 0 Ketchikan 191,800 62,700 30,043 99,057 0 Quartz Hill 250,300 0 53,209 197,091 0 Prince of 23,280 0 23,280 0 0 Wales Is. Metlakatla 24,600 22,150 2,450 0 _0 Total 1,026,595 260,790 240,773 525,032 0 7-24 Results of the Economic Analysis Base Case Expansion Plan The Base Case, which represents system expansion by the addition of diesel generation, with only the existing intertie connections, is used as the basis of comparison of the alterna- tive intertie expansion plans. The following table lists the cumulative present worth for each load center under the Base Case scenario. Table 7-14 BASE CASE EXPANSION PLAN PRESENT WORTH SUMMARY 50 Year Cumulative Load Center Present Worth x Skagway 11,169 Haines 30,604 Green's Creek 33,962 Juneau 58,134 Hoonah 18,745 Kake 12,141 Sitka 96,393 Angoon 10,512 Tenakee i574 Petersburg/Wrangell 20,136 Ketchikan 80,757 Quartz Hill 448,295 Prince of Wales Is. 56,722 Metlakatla 11,225 Total 890,365 Intertie Expansion Plan A Intertie Expansion A has an overall B/C ratio of 1.25 when compared to the Base Case Plan. As Table 7-15 reveals, the Quartz Hill interconnection (importing B.C. Hydro energy) has a definate advantage, with a B/C ratio of 1.47 when compared to the cost of supplying its own diesel generation. The Swan Lake-Tyee Lake intertie has an optimum B/C ratio of 1.23, when the Swan Lake-Tyee intertie begins operation in the year 2002. The Juneau-Green's Creek intertie (34.5 kV) has a B/C ratio of 1.26, assuming 1990 to be its on-line year. 7-25 Without the B.C. Hydro-Quartz Hill interconnection (Quartz Hill on-site diesel), the overall B/C ratio for Expansion Plan A would drop to 1.04. Considering all Southeast Alaska except Quartz Hill, Expansion Plan A has a B/C ratio of 1.09. Table 7-15 INTERTIE EXPANSION PLAN A SUMMARY OF ECONOMIC ANALYSIS RESULTS Diesel Expansion Base Case Plan A Interconnected Cumulative Cumulative B/C Load Centers (Year) Present Worth Present Worth Ratio ($ x 1,000) ($* x 1,00) Juneau-Green's Creek (1990) 90,096 73,086 1.26 Petersburg-Wrangell- Wrangell-Ketchikan (2002) 100,893 82,010 1.23 Quartz Hill-B.C. Hydro (1995) 448,295 305,537 1.47 Total S.E. Alaska with B.C. Hydro to Quartz Hill 890,365 709,716 125 Total S.E. Alaska without B.C. Hydro to Quartz Hill 890,365 852,747 1.04 Total S.E. Alaska except Quartz Hill 442,070 404,179 1.09 Intertie Expansion Plan B Table 7-16 summarizes the results of the analysis of Inter- tie Expansion Plan B. The intertie to Sitka from Juneau via Green's Creek, Hoonah, and Tenakee Springs has an optimum B/C ratio of 1.13, when the 69 kV Juneau-Green's Creek intertie begins operation in the year 1990 and the remaining interties begin operation in the year 2003. As mentioned in the discus- sion of the screening analysis results, the incremental segments of this Plan are too expensive for the small load demands at Hoonah, and Tenakee, but the savings at Sitka is large enough to 7-26 compensate for the losses that would have existed at each of the other load centers. The required 69 kV Juneau-Green's Creek connection has a B/C ratio of 1.07. The Petersburg-Wrangell-Ketchikan interconnection has a B/C ratio of 1.23 when the Swan-Tyee intertie begins operation in the year 2000. Quartz Hill supplied by B.C. Hydro has the same cost and B/C ratio (1.47) for Expansion Plan B as it does in Expansion Plan A. The Total S.E. Alaska B/C ratio for Intertie Expansion Plan B is 1.26 with the Quartz Hill intertie to B.C. Hydro and 1.05 with Quartz Hill supplied by on-site diesel generation. Excluding Quartz Hill, the Plan B B/C ratio for S.E. Alaska is Went les Table 7-16 INTERTIE EXPANSION PLAN B SUMMARY OF ECONOMIC ANALYSIS RESULTS Diesel Base Expansion Plan B Interconnected Case Cumulative Cumulative B/C Load Centers (Year) Present Worth Present Worth Ratio ($ x 1,000) ($* x 1,000) Juneau-Green's Creek (1990) 92,096 86,392 1.07 Juneau-Green's Creek- Hoonah-Tenakee-Sitka (2003) 208,805 184,982 Ves Petersburg-Wrangell- Ketchikan (2002) 100,893 82,010 1.223 Quartz Hill-B.C. Hydro (1995) 448,295 305,537 1.47 Total S.E. Alaska with B.C. Hydro to Quartz Hill 890,365 704,905 aaZe Total S.E. Alaska without B.C. Hydro to Quartz Hill 890,365 847,663 1205 Total S.E. Alaska except Quartz Hill 442,070 399,368 ‘Teall 7-27 Intertie Expansion Plan C Explansion Plan C can be viewed as an interconnection of the Green's Creek and Quartz Hill mines with the Tyee and Snettisham projects. The assumed commencement dates of mining operations in this expansion plan dictate the required on-line dates for the transmission interconnections. As shown in Table 7-17 the assumed dates are 1990 for Green's Creek and 1995 for Quartz Hill. The B/C ratio for the interconnected load centers for Intertie Expansion Plan C is 1.31. For all S.E. Alaska the B/C ratio of Plan C is 1.21. Since this plan would not be viable without Quartz Hill no B/C ratio for Total S.E. Alaska except Quartz Hill was calculated. Table 7-17 INTERTIE EXPANSION PLAN C SUMMARY OF ECONOMIC ANALYSIS RESULTS Diesel Expansion Base Case Plan C Interconnected Cumulative Cumulative B/C Load Centers (Year) Present Worth Present Worth Ratio (S$ x 1,000) ($ x 1,000) Green's Creek Juneau- Kake-Petersburg- Wrangell-Ketchikan- Quartz Hill (1995) 653,425 497,759 1.311 Total S.E. Alaska 890,365 734,700 1.220 Intertie Expansion Plan D As shown in Table 7-18, Intertie Expansion Plan D, which includes a Sitka-Tyee interconnection rather than Tyee-Swan Lake (Ketchikan), has a B/C ratio for all S.E. Alaska load centers of 1.23. As before (Plans A and B) the Juneau-Green's Creek inter- tie and the Quartz Hill-B.C. Hydro line have B/C ratios of 1.27 and 1.47, resepctively. The Sitka-Tyee interconnection, how- ever, is only marginally feasible, with a B/C ratio of 1.03. Furthermore, without Quartz Hill, the all Southeast Alaska B/C ratio for Expansion Plan B decreases to 1.06. 7-28 Table 7-18 INTERTIE EXPANSION PLAN D SUMMARY OF ECONOMIC ANALYSIS RESULTS Diesel Expansion Base Case Plan C Interconnected Cumulative Cumulative B/C Load Centers (Year) Present Worth Present Worth Ratio ($ x 1,000) ($x 1,000) Juneau-Green's Creek (1990) 92,096 72,546 Te27. Sitka-Kake-Petersburg- Wrangell (2006) 128,670 124,571 1.03 Quartz Hill-B.C. Hydro (1995) 448,295 305,537 1.47 Total S.E. Alaska with B.C. Hydro to Quartz Hill 890,365 723,958 13:23 Total S.E. Alaska without B.C. Hydro to Quartz Hill 890,365 866,716 1.03 Total S.E. Alaska except Quartz Hill 442,070 418,421 1.06 Summary of Results Based on these results, the following observations are made: e Utilizing the surplus Snettisham/Crater Lake hydro generation at Green's Creek is economically attractive. e Utilizing the surplus Snettisham/Crater Lake hydro generation by interconnecting Juneau-Green's Creek- Hoonah-Tenakee-Sitka is also economically attractive. e A Petersburg-Kake-Sitka connection, which would uti- lize the surplus energy generation of Tyee, is only marginally feasible. I= 239 e A Swan Lake-Tyee connection, which would enable Ketchikan to utilize the surplus from Tyee Lake is economically attractive. e A Snettisham-Kake-Petersburg-Tyee Lake-Swan Lake- Quartz Hill interconnection would utilize all surplus S.E. Hydro electric energy presently developed and is economically feasible. e A Quartz Hill interconnection with B.C. Hydro, without an intertie to Swan Lake is very attractive. Based on these observations, Expansion Plan B, which has separate interconnections of (1) Juneau-Green's Creek-Hoonah- Tenakee Springs-Sitka, (2) Petersburg-Wrangell-Ketchikan via Tyee-Swan Lake, and (3) Quartz Hill-BC. Hydro, is the selected expansion plan. This plan is the most economic plan, based on the assumptions present herein, with and without Quartz Hill. It would utilize almost all of the surplus energy available from the Tyee and Snettisham/Crater Lake hydroelectric developments to satisfy the load demand in Hoonah, Tenakee Springs, Sitka and Ketchikan as well as the Green's Creek Mine. Further, implemen- tation of the Snettisham and Tyee subsystems will not be depen- dant on development of Quartz Hill Mine but will proceed as load growth in the community load centers dictate. Sensitivity Analyses A sensitivity analysis of the impacts of variations in the following major economic parameters on Expansion Plan B were performed: Discount rate Fuel price forecast Electric load demand forecast Intertie on-line date Table 7-19 shows the sensitivity analysis results for Expansion Plan B (Northern System) and Total S.E. Alaska. Sensitivity to Discount Rate Under a variation in the discount rate, the cumulative worths of the Base Case Expansion Plan and Expansion Plan B decrease as the discount rate increases. However, the relative variation between the two scenarios is very slight. As shown in Table 7-19, the B/C ratio of the interconnected Northern System communities at a 4.5% discount rate remains at 1.13 and the Total S.E. B/C ratio remains at 1.26. 1=30 Table 7-19 RESULTS OF THE SENSITIVITY ANALYSES INTERCONNECTION: Expansion Plan B (Northern System) Juneau-Green's Creek-Hoonah-Tenakee Springs-Sitka Expansion Loaal/ Fue12/ Discount Base Case Plan B B/C Ratio M M 3.50% 208,805 184,982 Tats M M 4.50% 173,480 153,294 Tels) M H 3.50% 236,074 195,314 Meieut M L 3.50% 181,534 174,655 1.04 H M 3.50% 319,916 226,226 1.41 L M 3.50% 130,996 165,576 0.79 INTERCONNECTION: Expansion Plan B Total S.E. Alaska Expansion Load1/ Fuel2/ Discount Base Case Plan B B/C Ratio M M 3.50% 890,365 704,905 1.26 M M 4.50% 726,642 S787973 lie120 M H 3.50% 1,014,260 798,944 Veyei7, M L 3.50% 766,471 670,747 Teo4 H M 3.50% 1,737,301 1,295,484 34 L M 3.50% 644,467 582,185 ted 1/ H-High, M-Medium, L-Low 2/ H-High, M-Mean, L-Low Sensitivity to Fuel Price Forecast Under the high fuel price forecast the B/C ratio of the Northern System interconnected load centers of Plan B rises from 1.13 to 1.21. Under the low fuel price forecast it drops to 1.04. The overall B/C ratio for Expansion Plan B increases from 1.26 to 1.27 under the high fuel price forecast, and drops to 1.14 under the low fuel price forecast. Table 7-19 summarizes the results. T= 3 As shown in Table 7-19, for the Expansion Plan B, Northern System communities, the B/C ratio increases from 1.13 to 1.41 under the high load demand forecast. Under the low load demand forecast, however, the Northern System is not economically feasible, having a B/C of 0.76. Expansion Plan B, Total S.E. Alaska, is less sensitive to load growth, having B/C ratios of 1.34 for the high load fore- cast and 1.11 for the low load forecast. Sensitivity to On-Line Date The year in which each segment of Intertie Expansion Plan B would come on-line was varied to determine the combination of dates with the highest overall S.E. B/C ratio. The optimum dates, based on the load forecasts and assumptions stated herein are as follows: Optimum Transmission Segment On-line Year Juneau-Green's Creek (69 kv) 1990 Green's Creek-Hoonah-Tenakee Springs-Sitka 2003 Tyee-Swan Lake 2002 Quartz Hill-B.C. Hydro 1995 1-32 Chapter 8 THE MOST ECONOMIC PLAN Description Expansion Plan B is the most economic Southeast Intertie plan identified under the assumptions of this study. As shown on Figure 8-1, the plan consists of interconnections of the Snettisham/Crater Lake Development with Sitka at 69 kv via Juneau, Green's Creek, Hoonah, and Tenakee Springs; Petersburg, Wrangell and Ketchikan via a 138 kV Tyee Lake-Swan Lake inter- cie; and a transmission line from B.C. Hydro at Kitsault to the Quartz Hill Molybdenum Mine. The selected routings for the required transmission line segments for Plan B are given in Chapter 6. Table 8-1 shows the required line terminations for the Most Economic Plan. Table 8-1 LINE TERMINATIONS Substation Location Year Requirements Juneau 1990 69 kV Expansion Green's Creek 1990 69 kv 2003 69 kV Expansion Hoonah 2003 69 kV Expansion Tenakee Springs 2003 69 kV Expansion Sitka 2003 69 kV Expansion Petersburg NA None Wrangell NA None Tyee Lake 2002 138 kV Expansion Swan Lake 2002 138 kV Expansion Ketchikan NA None Quartz Hill - 100 kV DC Converter FIGURE 8-1 ~ WHITEHORSE Ps SKAGWAY @ aL O HAINES @ : . C4 Wi Ad, oa JUNEAU GREENS CREEK @ ancoon PRINCE LEGEND: OF WALES ISLAND LOAD CENTERS e@ GENERATION SOURCES EXISTING T/LINE PROPOSED T/LINE VOLTAGE COST(MILLIONS) HHARZA enaineenins comeany CCTOSES 1987 SNETTISHAM- CRATER LAKE PETERSBURG TYEE LAKE KETCHI KAN s00KV DC (BIPOLAR). 3 e@ QUARTZ e i tI METLAKATLA Pada ee aban) KITSAULT ALASKA POWER AUTHORITY SOUTHEAST INTERTIE STUDY MOST ECONOMIC PLAN Costs Table 8-2 shows the estimated cost of the Most Economic Plan. The costs shown include a contingency allowance of about 20% on all but submarine cable manufacturing costs, and an engi- neering and owners cost allowance of about 17.5 percent. Opera- tion and maintenance costs are estimated to be 1.0 percent of original installation costs or about $1.5 million per year, including the cost of the manned DC converter station. Implementation As a part of the economic analyses performed the optimum year of initial operation was established for each segment of the Expansion Plan B transmission system. Based on the medium load forecast these are as follows: Optimum Year of Segment Initial Operation Juneau-Green's Creek 1990 Green's Creek-Sitka 2003 Tyee Lake-Swan Lake 2002 B.C. Hydro-Quartz Hill 1995 (assumed year of initial mine operation) As indicated above, the most immediate attention should be given to studies to support the implementation of the Juneau- Green's Creek transmission segment, followed by Tyee-Swan Lake and Green's Creek-Sitka. Studies of the B.C. Hydro-Quartz Hill segment should be scheduled as necessary to support planning for mining operations. In advance of detailed engineering and design of the trans- mission facilities the following engineering studies should be undertaken: ie Juneau-Green's Creek Intertie Definite Project Report. A detailed feasibility study of the proposed 69 kV interconnection of Alaska Electric Light & Power's system on Douglas Island with Green's Creek Mine should be undertaken. The study should include a preliminary route survey, an assessment of foundation conditions along the proposed route, an environmental assessment, a detailed financial analysis including input from AEL&P, the Alaska Power Administration and Green's Creek Mining Company, and preparation of a definite project report. Consideration may be given to designing the line for 69 kV (to facilitate its future extension to Sitka) but operating it initially at 34.5 kV. Because the submarine cable survey con- 8-2 FERC Account No. 350 353 255 356 358 359 MOST Item Land and Land Rights Station Equipment Poles and Fixtures Overhead Conductors and Devices2 Underground Conductors and Devices Roads and Trails (Clearing) Communications Systems Subtotal Direct Cost Contingencies Subtotal Construction Cost Engineering and Owners Cost Total Cost January 1987 Price Level 17: U.S. facilities only. 2/ Included in Account No. Table 8-2 ECONOMIC PLAN - SUMMARY COST ESTIMATE (Cost in $ Thousands) Juneau Green's Crk. Tyee Lake B.C. Hydro to to to to Green's Crk. Sitka Swan Lake Quartz Hilll/ Total 160 680 350 170 1,360 1,350 3,810 5,560 19,050 29,770 2,830 13,900 9,040 4,260 30,030 9,570 24,610 1,460 2,970 38,610 880 4,200 4,240 1,710 11,030 200 600 200 2,000 3,000 14,990 47,800 20,850 30,160 113,800 2,250 7,120 4,010 5,420 18,800 17,240 54,920 24,860 35,580 132,600 2,450 8,150 4,240 5,710 20,550 19,690 63,070 29,100 41,290 153,150 355 above. ducted in 1986 indicated a feasible route, no addi- tional submarine surveys appear to be necessary to support the detailed feasibility study of this inter- connection. ax Tyee-Swan Lake Intertie Definite Project Report. A detailed feasibility study of the Tyee-Swan Lake interconnection should be undertaken. The study should include a preliminary route survey, an assess- ment of foundation conditions along the proposed route, an environmental assessment, detailed financial analysis and the preparation of a definite project report. 3. Green's Creek-Sitka Routing Studies. Additional pre- liminary studies are required to establish the route for this transmission segment. Studies performed should include comparisons of various alternative routes between the load centers, assessment of the potential environmental impacts of alternative routes and subsequent verification of proposed submarine cable crossings by side-scan sonar survey. These studies should be followed by detailed feasibility studies of the selected route including financial analysis. 4. Studies to support the required permit applications listed below. Required Permits Table 8-3 lists the permits and regulation which may apply for implementation of the Expansion Plan B transmission facili- ties. The list includes the temporary permits which would be required by installation contractors as well as the general project permits. Table 8-3 PRINCIPAL PERMITS THAT MAY BE REQUIRED Agency State of Alaska Alaska Office of Management and Budget Alaska Dept. of Environmental Conservation Alaska Department of Fish and Game Alaska Department of Natural Resources Alaska Department of Trans- portation & Public Fac. 8-4 Permit/Regulatory Requirements Coastal Management Program Certificate of Consistency and Coastal Project Questionnaire Air Quality Permit to Open Burn Water Quality Certification (Clean Water Act Section 401) Solid Waste Disposal Permit Food Service Permit Wastewater Disposal Permit Plan Review for Sewerage System or Water & Waste- water Treatment Anadromous Fish Protection Permits (Title 16) Land Use Permits (state land) Water Rights Permit and Certificate of Appropria- tion Right-of-way Easements and Licenses (state lands) Material Sales Permit Permit to Burn Notification of Operation Timber Harvest-Private Lands Utility Permit (on State ROW) Table 8-3 (cont'd) PRINCIPAL PERMITS THAT MAY BE REQUIRED Agency Federal Department of Energy ® National Marine Fisheries e Corps of Engineers e e U.S. Forest Service e e e e e Environmental Protection Agency e Federal Aviation Administration e Federal Communication Commission e Native Corporations e City & Borough e 1/ Includes clearance from State Office. 2/ Permit/Regulatory Requirement Presidential Permit (for B.C. Hydro-Quartz Hill only) Letter on consultation for Sec. 7 of the Endangered Species Act Section 10, Rivers and Harbors Act, Section 404, Clean Water Act ANILCA Review Special Use Permitl/ Environmental Impact Analysis2 Cultural Resource Survey ROW Timber Sales Agreement ANILCA Review National Pollutant Discharge Eliminations Systems Notice of Proposed Construc- tion 7460-1 Permit Radio License and permit to Operate Easements Planning & Zoning Review and Easements Historic Preservation Environmental Analysis refers to NEPA requirements for either environmental assessment or environmental impact statement, depending on perceived impacts. 8-5 Bibliography Gag cde a GO BIBLIOGRAPHY Acres International Corp. 1986. Evaluation of Corridor Alter- natives. Juneau Access (Lynn/Taku Corridor). Southeast Alaska Transportation Plan. March 1986. Acres International Corp. 1986. Evaluation of Corridor Alter- natives. Sitka Access. Southeast Alaska Transportation Plan. March 1986. 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