An Analysis of Energy and Carbon Intensities and Exergy Efficiency in Natural Gas Combined-Cycle Power Plants: A Case Study of Thailand

Abstract

The objectives of this study were to estimate energy and carbon intensities of natural gas combined-cycle power plants and to improve the energy efficiency of power plants through an exergy analysis. Three plants in Thailand were evaluated as case studies in this research using data collected in 2013 – 2014. The results showed that the average carbon and energy intensities of three Combined-Cycle Power Plants were 0.436 kg CO2/kWh and 7.995 GJ/MWh, respectively. The range of the energy intensity in this study was slightly lower than that of other studies; however, the results of the carbon intensity were in the same range. The result of the exergy analysis illustrated that Heat Recovery Steam generator (HRSG) has the greatest exergy destruction due to the wide temperature range. To summarize, natural gas combined-cycle power plants require less energy and emit less carbon compared to other technologies or fuels. The exergy efficiency of HRSG was 60%, with an exergy destruction rate of 66.88 MW. One approach to improve the efficiency of power plants is to improve the efficiency and performance of HRSG