Comparative exergoeconomics of power utilities: Air-cooled gas turbine cycle and combined cycle configurations

Population explosion, depletion of fossil fuel and environmental regulations related to emission from power utilities has been challenging the utility developers to promote cost effective, fuel efficient and clean energy. This article focuses on comparative exergoeconomic study of gas turbine power utility and a combined cycle utility. By its very nature combined cycle includes more number of cycle components as compare to the basic gas turbine cycle and hence the investment cost for the combined cycle power plants is higher in terms of total cost rate. The present work also focuses on the advantages of developing combined cycle based power utility in comparison to gas turbine based utility in terms of its exergoeconomics. Exergoeconomic analysis of utilities based on each of these cycles has been carried out keeping the operating parameters constant i. e. (rpc = 10, TIT = 1500 K, ηAC = 88% and ηGT = 90%). Results obtained highlights that with 4.47% higher total cost rate, combined cycle develop 21% higher power output equivalent to 48.71 MW. Combined cycle based utility exhibits higher exergy efficiency in comparison to basic gas turbine based utility, with combined cycle delivering 21.16% higher exergy efficiency when the cost of electricity (3.32 cents/kWh) is marginally higher by 13.3%.