Decision framework for sustainability assessment of alternative fuels to achieve shipping decarbonization

The transition of shipping industry towards full decarbonization is under way, driven by regulations, the IMO's decarbonization targets, pressure from cargo owners, financial incentives, and evolving societal expectations. However, the need for a comprehensive framework to evaluate fuel options impedes the maritime industry's transition to alternative fuels. Stakeholders are still searching the most suitable alternative fuels which will ensure both the regulatory compliance and economic benefits. Hence, the study aimed to determine the most promising alternative fuel for the shipping industry based on a robust set of alternative fuel selection criteria and establish a comprehensive decision-making framework within a global context using a mixed-methods approach. The study identified an integrated set of sustainability criteria for alternative fuels utilizing systematic literature review framework and adopted the Best Worst Method (BWM) for determining the relative weight of criteria. Finally, the TOPSIS method has been used to outrank the alternative fuels-methanol, hydrogen, biofuel, ammonia, and LNG. The study concludes that methanol exhibits the highest potential as a sustainable future clean fuel, followed by hydrogen, biofuels, ammonia, and LNG respectively. The findings of the study are generalized as a decision support system to assist the stakeholder while making robust and comprehensive decisions about the choice of sustainable fuels through a balanced and all-encompassing view.