This study investigates the effects of using ethanol and biodiesel in diesel fuel blends on the performance and emissions of a fixed-speed diesel engine used in power plants. The blend leverages ethanol's high oxygen content and cooling properties, combined with biodiesel's renewable nature and favorable combustion characteristics, to improve engine efficiency and reduce pollutant emissions. Blending these fuels with diesel enables a sustainable, cost-effective fuel option that can help mitigate environmental impacts without compromising power output in stationary applications. A quantitative analysis of a diesel engine operating with a blend of 70% diesel, 20% biodiesel, and 10% ethanol by volume (D70B20E10) demonstrated a 5% reduction in specific fuel consumption compared to conventional diesel fuel, decreasing from 0.28 kg/kWh to 0.266 kg/kWh. The oxygenation effect of both ethanol and biodiesel helped reduce particulate matter (PM) emissions by 40%, while nitrogen oxide (NOx) emissions dropped by 15% due to the ethanol-induced cooling effect, which lowered peak combustion temperatures. Additionally, under continuous load operation, the brake thermal efficiency improved by approximately 6%, rising from 35% with standard diesel to 37.1% with the D70B20E10 blend. These results illustrate that the use of ethanol-biodiesel-diesel blends offers a feasible pathway to enhance fuel efficiency and lower emissions in fixed-speed diesel engines, providing a valuable strategy for cleaner energy production in power plant applications.