7.1 Calculate the Internal Rate of Return (IRR) for an investment in a 400-MW power plant with an expected life of 30 years. This plant costs 1200 $/kW to build and has a heat rate of 9800 Btu/kWh. It burns a fuel that costs 1.10 $/MBtu. On average, it is expected to operate at a maximum capacity for 7446 h per year and sell its output at an average price of 31 $/MWh. What should be the average price of electrical energy if this investment is to achieve a MARR of 13%? 7.2 What would be the Internal Rate of Return of the unit of Problem 7.1 if the utilization rate drops by 15% after 10 years and by another 15% after 20 years?