Valorization of biodiesel from waste vegetable and animal resources: advancing circular bioenergy through sustainable automotive and marine fuel blends

Purpose This study aims to assess the feasibility of integrating biodiesel – derived from waste vegetable oils and animal fats – into marine diesel blends to reduce emissions while maintaining engine performance. This research focuses on quantifying changes in combustion efficiency and exhaust emissions across different biodiesel formulations, specifically analyzing their impact on greenhouse gas (GHG) emissions in maritime applications. Design/methodology/approach This study uses an experimental approach using controlled combustion tests on a marine diesel engine to evaluate biodiesel blends’ effects on emissions and performance. Various formulations (plant-based, animal-based and mixed) are tested against marine gas oil (MGO). Fuel blends (B20, B50 and B100) are prepared and analyzed under standardized conditions. Engine load variations simulate real-world operations, while exhaust gas analysis measures CO2, CO, NOx, and O2 emissions. Combustion efficiency is assessed through thermal efficiency, specific fuel consumption and power output. A comparative approach ensures reliable results, highlighting biodiesel’s feasibility as a marine fuel alternative with significant environmental benefits. Findings This study confirms biodiesel’s potential to reduce maritime emissions while maintaining engine performance. CO2 emissions decrease by 30%, consistent with biodiesel’s lower carbon content, while CO emissions drop by up to 94% because of improved combustion. However, NOx emissions rise by 30%, a known trade-off linked to higher combustion temperatures. Engine efficiency remains stable across blends, with minimal increases in specific fuel consumption for higher biodiesel concentrations. Economically, biodiesel adoption aligns with International Maritime Organization regulations, supporting decarbonization efforts. These findings reinforce biodiesel’s viability as a cleaner alternative for the shipping industry’s transition toward sustainability. Originality/value Unlike previous studies that focus primarily on biodiesel use in land-based transportation, this research uniquely addresses its application in the maritime sector. By directly evaluating marine diesel engines under controlled conditions, this study provides industry-specific insights critical for policymakers, shipping companies and environmental agencies. The emphasis on waste-derived biodiesel further enhances its sustainability impact, presenting a practical solution for decarbonizing maritime transport.