Comparative assessment of alternative marine fuels in life cycle perspective

Alternative marine fuels are accepted and used as an important solution for preventing ship-related air-borne pollutants. Studies of international organizations such as IMO on these fuels are increasing and gaining importance. However, assessing the environmental performances of these fuels, which generally produce much less pollutants than fossil fuels during operation, a life cycle perspective will provide a comprehensive understanding of which one is more environmentally efficient. In this study; biogas, dimethyl ether, ethanol, liquefied natural gas, liquefied petroleum gas, methanol, ammonia, and biodiesel were determined as alternative fuels and their environmental damages during life cycle were evaluated in life cycle perspective. SimaPro V9.0.0.49 and ReCiPe 2008 V1.09 were used for the assessment. The results focused on the effects on human health, ecosystem, resource utilization, emission inventory, and social costs. Thus, a complete evaluation was achieved for all alternative fuels considering not only the operating conditions but also the production process. Biogas was found as the best fuel in the short, medium, and long term; methanol, ammonia, and biodiesel group performed worst. While biogas causes 0.9 tons of CO2 production, methanol, ammonia, and biodiesels produce 1.5, 4.8, and 1.6 (average) tons of CO2, respectively. Despite the doubts on production, transfer, and storage, biogas was also identified as the most sustainable type of fuel.