A systematic review on the acceptance of alternative marine fuels

The environmental effects of conventional fossil fuels used in maritime sector is a well-studied subject and various methods, i.e. hull optimization, engine modifications, alternative propulsion systems, and alternative energy sources, have been suggested and implemented for years to reduce these effects. Although the utilization of alternative fuels is accepted as the most effective method, these fuels have their disadvantages as well as advantages they provide. This study mainly aims to evaluate the alternatives (ammonia, biofuels, dimethyl ether, ethanol, hydrogen, liquefied natural gas, liquefied petroleum gas, and methanol) through a comprehensive literature review. For this purpose, the publications obtained from Web of Science were searched using the keyword alternative marine fuels and the studies accessed were evaluated. In this context, the study is one of the most comprehensive reviews on alternative marine fuels and aims to discuss the future of alternative fuels through the evaluation of existing studies. The properties of these fuels have been examined in detail, taking care not to miss any point. Driving forces and obstacles for alternative fuels to be called conventional fuels have been evaluated in line with the United Nations' Sustainable Development Goals. In light of the gathered information, it has been concluded that the global-scale use of alternative fuels is still at an early stage due to several major concerns, i.e. technical and environmental incompatibilities, cost issues, and insufficient training level of seafarers, and that future studies should be carried out, especially within the life cycle perspective.