3.10 The following table gives capital costs and variable costs for a coal plant, a natural gas combined-cycle plant, and a natural-gas-fired gas turbine: COAL NG CC NG GT Capital Cost (S/kW) 1,500.00 $,000.00 500.00 2.50 Variable Cost (/kWh) 4.00 8.00 The utility uses a fixed charge rate of 0.10%r for capital costs. Its load duration curve is shown as follows 8000 7000 6000 5000 Z 4000 3000 2000 1000 0 0 1000 2000 3000 4000 5000 6000 7000 8000 HRS/YR Figure P3.10 a. Draw the screening curves (Revenue Required S/yr-kW vs hr/yr) for each of the three types of power plants. b. For a least-cost combination of power plants, how many MW of each kind of power plant should the utility have? If you plot this carefully, you can do it graphically. Otherwise you may need to solve algebraically. c. Estimate the average capacity factor for each type of power plant d. How many MWhr of electricity would each type of power plant generate each year