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. . Utilitv Range of Nee!! for Peaking Capacity (MW) Public Service Company of New Mexico Utah Power and Light Company Arizona Public Service Company 200 - 300 100 - 150 100 - 200 The greater loads in the California-Southern Nevada area have a greater need for peaking power. The installed capacity selected for this preliminary investigation at San Miguel Canyon is 170 MW. As the potential power market is more precisely defmed the plant size can be modified to obtain the best fmancial return. Site Conditions A visit to the potential site of the San Miguel Hydropower Project was made in June 1987. The site inspection team was composed of individuals experienced in tbe fields of geotechnical engineering, embankment design, facilities construction, and water resources planning. No apparent site conditions which would preclude construction of the facilities or require extraordinary measures for construction were discovered. The sandstones found at both the upper and lower reservoir sites were appraised as being strong and relatively incompressible, providing good foundations for the dams. However, permeability through the sandstones of the foundations and abutments would likely require corrective measures during construction. The slopes formed on both sides of the canyon at the lower reservoir site appeared stable and should not be affected by the impounded waters. Estimate of Canital and Oneration Costs of San Milruel Canvon HvdrQoower Protect Reconnaissance-level cost estimates were developed on the basis of available mapping from previous slUdies, a geotechnical and design tearn site visit to appraise construction conditions, and preliminary design dimensions developed in this study. A direct construction costs subtotal was estimated by adding the estimated capital costs associated with constructing the required facilities and the estimated costs of mechanical features associated with the power house. Quantity estimates based on preliminary design dimensions multiplied by unit costs were used to estimate capital construction costs. The cost of mechanical features such as turbines and generators were estimated from manufacturer's quotations and bid abstracts with allowances for installation added. The costs were indexed to July 1987. Future inflation was not included. To the direct construction cost subtotal, allowances for contingencies and for engineering and construction administration were added to obtain an estimated total constrUction cost. For this preliminary investigation, a 30 percent contingency was provided for uncertainties in estimated quantities and costs and for unknown conditions. An additional allowance of 20 percent was included for engineering design, constrUction observation, administration by the engineer and the owner and legal expenses. The capital cost estimate for the San Miguel Canyon Project is summarized in Table 3. In addition to capital costs, annual operating expenses associated with the hydropower facilities must also be considered. Operating, maintenance and repair costs were estimated at $750,000 per year. Off-peak pumping costs were estimated to be $9,220,000 per year based upon a combined demand and energy rate of $0.02 per kWh. To correlate cost estimates with pertinent cost experience, actual construction bid abstracts for the Ml. EIben pumped storage hydropower plant, a 200 MW installation near Leadville, were tabulated. Structure, equipment and operating costs from four othet western U.S. plants in the 100 to 400 MW range were also compiled and compared. Page 4