Q. Consider substituting natural gas for coal at Nanticoke. In this case it will be better to build a modern gas-fired generation plant rather than attempting to retrofit the existing coal plant. A combined cycle natural gas plant would cost about $756M. Money would have to be borrowed to build the new natural gas plant at an interest rate of 6 percent per year. The equalized debt charge (capital and interest) for 25 years on $10,000 of borrowed capital is $2.11/day. Assume the efficiency (thermal to electric) of the combined cycle natural gas plant is 0.65 and its average plant capacity is 95 percent. The combustion of natural gas yields thermal energy of 39MJ m-3 and 51 g of CO2 are produced per MJ. In order to compare with question 1 above, consider replacing a Nanticoke unit with a single 485 MW (e) natural gas plant with no pollution control.

a) Calculate the volume of natural gas (m-3) consumed per year by this plant.

b) If the long term contract price of natural gas to large consumers is pegged at $3.0/GJwhat is the average fuel only cost ($/ kWh) of the electricity produced?

c) Calculate the total cost ($/kWh) of electricity delivered to the grid including fuel cost and debt charge with O&M of 5% added to the total.

d) How much CO2 (Mt) does the plant produce annually?

e) Suppose that an amount of natural gas equal to 0.50 percent (realistic) of the natural gas consumed is lost in leaks during its extraction, production and transmission. Make the reasonable approximation that natural gas is 100 percent methane. Further guess that 1kg of methane is equivalent to 20kg of CO2 in terms of its climate change effect on the atmosphere. Compute the total greenhouse gas emission (combustion + leaks)