Comparative Life Cycle Assessment of Alternative Marine Fuels

With the stricter rules introduced by the policymakers in maritime transportation, harmful emissions are aimed to be mitigated. Consequently, studies on alternative fuels have emerged, and different methods had adopted to evaluate fuel choices. Within this context, a well-to-wake life cycle assessment method is used to determine the environmental impacts of the fuel options. Included fuels in the study are ammonia, biodiesel, Dimethyl ether, electro Fischer Tropsch diesel fuel, electro methanol, Fischer Tropsch diesel fuel, hydrogen, liquefied natural gas, liquefied petroleum gas, marine diesel oil, marine gas oil, marine bio-oil, methanol, pyrolysis oil, renewable diesel, straight vegetable oil, and ultra-low sulfur heavy fuel oil. The paper aims to evaluate the fuels according to the 2050 strategy of the International Maritime Organization. Hence, black carbon, carbon monoxide, carbon dioxide, nitrous oxide, nitrogen oxide, sulfur oxide, particulate matter, methane, and volatile organic compounds are considered emissions. During the study, an ocean tanker model available in the GREET Model 2022 was used for life cycle inventory analysis, and life cycle assessment was conducted by Environmental Footprint Method 3.0, which is included in the OpenLCA. The assessment was carried out according to climate change, acidification, freshwater ecotoxicity, marine eutrophication, terrestrial eutrophication, non-cancer human toxicity, particulate matter, and photochemical ozone formation criteria. The results show that out of eight criteria, marine bio-oil became the most dominant choice due to the consumption of CO₂ and methane while producing and low emission generation during combustion.