Homework Problems
1. A 500 MW power plant, operating at full capacity, has a heat rejection of 3.5x109 Btu/hr. What is
its efficiency?
2. It takes 2.2 million tons of coal per year to fuel a 1000-MW power plant that operates at a
capacity factor of 70%. If the heating value of the coal is 12,000 Btu/lb, calculate the plant’s
efficiency and the heat rate.
3. If the ultimate analysis of the coal in problem 1 is 69.76%C, .4.65%H, Nitrogen 1.24%, Sulfur
3.50%, Oxygen 8.14%, and Ash 12.71%, determine the air fuel ratio for 25% excess air (λ = 1.25)
combustion. Assuming that all the sulfur in the coal reacts to SO2, determine the emission rate of
SO2 in pounds per million Btu of heat input. What are the CO2 emissions per Btu of heat input for
this coal?
4. The coal plant of problems one and two has a measured NOx concentration of 10 ppm in the
exhaust. Assuming that the oxygen content of the exhaust is the same as that computed for
complete combustion, determine the emission rate of NOx in pounds per million Btu.
5. Problem 5.2 in text.
6. This is a revised version of problem 5.10 in text. Using the approach outlined in Table 5.3,
estimate the busbar cost of electricity generated by a CCGT power plant with the following
characteristics:
Overnight capital cost: $500/kWe
Construction time c = 3 yrs
Thermodynamic efficiency = 50%
Initial O&M cost (O/K)0 = $27/kWe/yr
Initial fuel cost, f0 = $2.60/KSCF
and all other parameters are as listed in Table 5.3
7. This is another revised version of problem 5.10 in text. Using the approach outlined in Table 5.3,
estimate the residential cost of electricity generated by a solar photovoltaic cell operating in the
Los Angeles area with the following characteristics:
Overnight capital cost: $9000/kWe
Construction time c = 0.25 yrs
An installation with a rated peak power of 3 kW will generate 4400 kWh in one year.
O&M costs are negligible and all other parameters are as listed in Table 5.3
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