Energetic, Exergetic, and Economic Analysis of Simple and proposal Combined Cycle Gas Turbine Power Plants: A Case Study of Al-Ruwais Power Station

Abstract

Gas Turbine power plants represent critical energy infrastructure in Libya; however, their performance is highly sensitive to ambient temperature variations. This study investigates the energetic, exergetic, and economic performance of Al-Ruwais Gas Power Plant, which located in Al-Hawamid in the Western Mountain region of Libya, by comparing the existing simple gas turbine configuration (two Siemens SGT5-2000E units) with a proposed Combined Cycle Power Plant integration. Thermodynamic simulations were performed using Aspen Plus over an ambient temperature range of 10–50°C. The CCPP significantly improves plant performance by recovering exhaust-gas heat through the Heat Recovery Steam Generator (HRSG) and generating additional power using the steam turbine. At 10°C, the simple cycle achieves a thermal efficiency of 35.28%, whereas the CCPP about was 49.81%. Moreover, the exergy analysis confirms that the combustion chambers dominate irreversibility losses (82.7%) in the gas cycle, while the HRSG was and condenser (51.4%) and (33.6%) respectively dominate the steam bottoming cycle losses. In addition, the economic assessment confirms that combined-cycle integration provides substantially stronger financial performance, with the Net Present Value (NPV) increasing from $367.41 M to $871.10 M and the Payback Period (PBP) decreasing from 9.19 to 6.21 years.