Techno-Economic Evaluation of a Natural Gas Combined Cycle Power Plant Based on the Brayton Cycle

Abstract

The growing demand for reliable and efficient electricity generation has increased the importance of natural gas combined cycle power plants (NGCCPPs) as a viable solution for meeting global energy needs. This study presents an economic evaluation of a Brayton cycle-based NGCCPP through the estimation of equipment purchase costs, capital investment requirements, and cost escalation analysis. The major plant components considered include the air compressor, combustion chamber, and gas turbine. Equipment costs were determined using established empirical cost correlations based on operating parameters such as air mass flow rate, pressure ratio, efficiency, and turbine inlet temperature. The estimated purchase costs of the air compressor, combustion chamber, and gas turbine were found to be approximately $4.5 million, $2.12 million, and $16 million, respectively, indicating that the gas turbine is the most significant contributor to equipment expenditure. The total equipment purchase cost was estimated at $22.5 million in the reference year 1992 and adjusted to $49.30 million in 2025 using the Chemical Engineering Plant Cost Index (CEPCI). Direct and indirect cost analyses were subsequently performed to determine the fixed capital investment and total capital investment of the plant. The results show that the fixed capital investment is approximately $261.92 million, while the total capital investment, including working capital, is estimated at $308.56 million (123.42 million OMR). The findings demonstrate that although major equipment costs significantly influence project economics, installation, service facilities, piping, and other supporting infrastructure contribute substantially to the overall investment. This study provides valuable insights into the economic viability of NGCCPPs and serves as a foundation for future optimization and investment decision-making in gas-to-power projects.