This paper analyses the performance and environmental impacts of gas turbine plants operating on diesel and natural gas. It provides a comprehensive assessment of how varying ambient temperatures and fuel type affect gas turbine operation and pollutant emissions. This is done under identical turbine inlet temperatures and net power to eliminate their effects and to enable a clearer comparison. Based on a case study of the Tripoli West 167 MW simple-cycle power plant, a thermodynamic model developed in Excel is used to simulate GT performance. Results indicate that as ambient temperature changes, net exergy destruction is primarily influenced by the exergy destruction changes in the turbine (~45%) and the compressor (~40%), although the combustor is responsible for over 80% of the net destruction in the cycle. The results also highlight the relationships between specific fuel consumption, net thermal efficiency, and pollutant emissions. For every 10 °C rise in ambient temperature, the net thermal efficiency declines by 1.55% and 1.5%, the specific fuel consumption rises by 1.57% and 1.52%, and pollutant emissions rise by 1.58% and 1.53% for diesel and natural gas, respectively. This may link the changes in net thermal efficiency and pollutant emissions to the specific fuel consumption. Switching from diesel to natural gas significantly reduces net exergy destruction (~73%), attributed to reduced combustor exergy destruction, and boosts overall thermal efficiency by about 1%. Switching to natural gas also reduces CO2 emissions by (~24%) due to a lower carbon-to-hydrogen ratio (~15.2%) and lower fuel consumption (~10.2%). The emission factors determined by this study are 3.082 kg CO2/kg fuel for diesel and 2.612 kg CO2/kg fuel for natural gas. The change in emission factor between diesel and natural gas is similar to the change in carbon-to-hydrogen ratio between the two fuels (~15.2%). This relates the CO2 emission factor to fuel chemistry. The findings suggest that using natural gas is preferable, especially in warmer months. 

This study aims to evaluate the performance of a simple cycle gas turbine power plant by analysing the effect of different operating parameters. These operating parameters include compressor pressure ratio and compressor & turbine isentropic efficiencies. The study quantitatively assesses the exergetic efficiency and the exergy destruction of each unit in the cycle, as well as the power used or produced by the cycle. Any change in these parameters can significantly impact the power plant's overall performance through a specific unit in the cycle. For instance, increasing the compressor pressure ratio can reduce the temperature difference across the combustor, lessening the exergy destruction and improving the cycle’s overall performance. However, any decline in the compressor or the turbine isentropic efficiency results in an increase in the exergy destruction of the affected unit and can result in a decrease in the overall cycle performance. This is due to either an increase in power required by the compressor or a decrease in power produced by the turbine. The analysis suggests that the turbine isentropic efficiency has a greater impact on the net power generated than the compressor isentropic efficiency. Additionally, the turbine inlet temperature is a dependent variable as operating at different compressor pressure ratios and compressor isentropic efficiencies lead to varying turbine inlet temperatures. Therefore, increasing the turbine inlet temperature does not always lead to improved performance.