Diesel engine is most commonly seen in applications demanding a large power output, such as ships and electric generation plants. Exergy analysis has been used in the design technology such as simulation and performance assessment of various types of engines, for identifying parameters. In this case; the energy and exergy analyses of an eight-cylinder, four-stroke power generator using the kerosene fuels with blended 20/50 aspire methly ester (AME) have been performed. Energy and exergy rates for the engine were determined and then various performance parameters and energy and exergy efficiencies were calculated for each fuel operation and compared with each other. The results of tested biodiesel offer similar energetic performance as petroleum diesel fuel. Conservation of energy equation and the exergy balance for each test steps were determined using measured data. Finally, various energetic and exergetic performance parameters of the engine were evaluated and compared with each other. CO emissions were dropped when running on AME and its blends. The AME was found to have the highest exhaust temperature due to its oxygen content 11.2% higher than marine fuel. The maximum NOx emission was indicated 100% AME blend. However, the NOx emissions were higher, using marine blends.