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Show CHAPTER III 93 The Environmental Task Force was chaired by U.S. Bureau of Reclamation and included representatives from Bonneville Power Administration. F.2.1 System Studies Task Force The following is a summary of the conclusions reached by the System Studies Task Force: (1) The technical requirements for a 1,440 MW or 2,200 MW transmission system between Pacific Northwest and Southwest could be most effectively met by a ± 500-kV bipolar overhead HVDC transmission line; i.e., 1,000-kV DCIntertie. (2) The best locatior for the northern terminal is Celilo. The preferred location for the southern terminal is the Phoenix area rather than Mead. The transmission line would be 1,054 miles long. (3) The system as proposed would enhance the performance of the connected AC systems. (4) When losses are accounted for, the effective transmission capacity of the DC system, defined as the power delivered to the receiving AC system at rated conditions, for the proposed 1,440 MW and 2,200 MW systems would be 1,326 MW and 1,940 MW, respectively. (5) Based on the effective transmission capacity, the estimated investment costs for the 1,440 MW and 2,200 MW systems would be $353/kW and $296/kW, respectively. (6) The incremental investment cost for the additional 614 MW transmission capacity available for the 2,200 MW system would be only $175/kW. Comparison of annual costs show similar potential advantage for the higher capacity system. (7) The 2,200 MW system could be built in two stages to accommodate potential growth of line loading and to effect additional benefits by deferment of investment costs for part of the terminals. (8) To meet the January 1984 energization date, award of construction contracts is required by April 1979. The cost estimates for the 1,400 MW system components are tabulated on Table 1 of "PNW-SW Intertie, dated February 1976." In order to meet growth of transmission capacity requirements, a viable alternative would be to build a 2,200 MW converter terminal in two stages. F.2.2 Economic Evaluation Task Force The evaluation by the Task Forces shows that the Celilo-Phoenix area 1,000 kV DC Intertie is feasible and that it should be completed by January 1984. The overall annual benefit-to-cost ratio for a 1,440 MW system is approximately 2.1 to 1, based on those benefits which can be evaluated. Total equivalent annual benefits are estimated to be $84,563,000 and annual costs $40,950,000. The total investment cost is estimated to be $467,600,000. Long-term benefits evaluated in this report are outlined below: (1) Exchanges of summer-winter surplus peaking capacity between the Northwest and Southwest to reduce capital expenditures for new generating capacity; (2) Sale of surplus Northwest secondary energy to Southwest utilities; and (3) Sale of Southwest energy to the Northwest to firm up peaking hydro sources during critical water years. The proposed Intertie would also provide a means for conservation of significant amounts of fossil fuels by the following: (1) Use of surplus hydroelectric energy; (2) Foregoing installation of thermal peaking resources; and (3) Increased efficiency of operation of hydro and thermal resources. F.2.3 Environmental Task Force The Task Force has agreed that environmental studies will be the individual responsibility of the U.S. Bureau of Reclamation and Bonneville Power Administration on those portions of the line under each agency's jurisdiction. However, study methods will be consistent. |