Assessment of Economic Viability of Conversion of Open Cycle to Combined Cycle Gas Power Plant

Abstract

The paper identified the types of gas turbines available in the electric power generating system in Nigeria and assessed the economic viability of converting open cycle to combined cycle gas power plants in order to maximize the electricity generation output without further gaseous fuel consumption in the existing thermal plants in the country. Data were obtained through primary and secondary sources on all the operational power plants in Nigeria. These data were analyzed using engineering economy methods. The result showed that by using the average generation of each plant for a period of 3 years as a baseline for conversion, an additional 1142.1 MW would be obtained after conversion to combined cycle without increase in gas consumption. In addition, the result showed the NPV values and benefit-cost ratio were greater than zero and one respectively, indicating that the project is economically viable for each conversion process. The sensitivity analysis over a range of values from ±10 to ±30% of the investment cost did not affect the economic viability of the project. Furthermore, the result showed that the cost of generating electricity borne by the society is much lower for a combined cycle than for an open cycle. The study concluded that conversion of the gas turbine from open cycle to combined cycle is economically viable and an additional generation of 1142.1 MW can be obtained without increasing the gas consumption.