Investigation and Examination of LNG, Methanol, and Ammonia Usage on Marine Vessels

This study aims to evaluate the use of LNG, methanol, and ammonia on ships as an alternative marine fuel. In this sense, firstly, the SWOT analysis is conducted, so the strengths and weak sides of the alternative fuels are determined. In the second step of the study, various criteria such as safety, cost, exhaust emission, global warming potential, sustainability, storage, and technical competence are specified, and the alternative fuels are analyzed with the TOPSIS method based on the identified criteria. As a result of the obtained judgments from the marine experts, the safety of fuel, its global warming potential, and its storage feature is determined as the most influential comparison weights. In addition, ammonia is determined as the best fuel option based on the 2.92 similarity value while values of LNG and methanol are calculated 2.21 and 2.18, respectively. Then, a sensitivity analysis where the various cases were created by improving the weights of criteria by 25% and applying the same weight value for each criterion is conducted to reveal the criticality of the criterion weighting. According to this analysis, it is observed that the analysis is highly sensitive to the global warming potential criteria. In line with this information, beneficial and significant key findings to policy-makers, stakeholders, and maritime companies are presented from the perspectives of short-term and long-term emission reduction strategies.