This study contributes to the maritime industry's pathway toward the IMO 2050 net-zero objective through an integrated approach that links design-constrained retrofit evaluation and fuel feedstock sources with life-cycle and cost assessments. Two representative vessels, a 49 m Ro-Ro ship operating on medium range routes and an 87 m car ferry operating on longer routes, are evaluated, with propulsion configurations divided into ICE systems and electric motor systems. Retrofit scenarios include electric propulsion using lithium-ion batteries and hydrogen fuel cells, and ICE propulsion operating on methanol and ammonia, both recognized for their potential to deliver low or near-zero carbon emissions. Environmental performance is assessed through a well to wake life cycle assessment, while the cost analysis incorporates feedstock sources to evaluate long-term cost feasibility under future decarbonization pathways. The retrofit feasibility assessment shows that all alternatives except pure battery-electric propulsion are technically achievable, with battery energy density as the limiting factor. From a life cycle perspective, hybrid diesel–electric propulsion, fossil based hydrogen fuel cells, fossil based ammonia ICE, and renewable energy based methanol ICE offer viable mid-term mitigation options, while only renewable energy based ammonia and renewable energy based hydrogen enable net zero decarbonization consistent with long-term climate objectives. Integrating retrofit feasibility, environmental performance, and cost assessment, the study highlights ammonia-based ICE systems as particularly promising solutions for achieving IMO 2050 targets, offering both technical feasibility and economic robustness under time horizon and scenario of this study.
Maydison et al. (Tue,) studied this question.