Assessment of cruise ship decarbonization potential with alternative fuels based on MILP model and cabin space limitation

Abstract

Alternative fuels are expected to play an increasingly crucial role in the decarbonization of the shipping industry. Previous studies have explored the possibility of ship integrated energy systems that use alternative fuels for emission reduction in a cost-efficient manner. However, the various navigation loads and strict space limitations of ships are usually overlooked when designing the ships' energy systems. To fill this gap, a two-stage optimization model is proposed for designing ship integrated energy systems that incorporate alternative fuels, which incorporates internal combustion engines, fuel cells, energy storage technologies, and other relevant equipment. The model captures the ship's volume and weight limitations for alternative fuel applications, and a large cruise ship sailing in Oceania and the Caribbean is selected as a case study. The application feasibilities of four mainstream alternative fuels, i.e., hydrogen, ammonia, methanol, and natural gas, have been compared with the conventional diesel power system considering the impact of future trends of fuel cost and emission-related policies. The results indicate that more than 60% of greenhouse gas emissions can be reduced by replacing conventional fossil fuels with alternative fuels. Meanwhile, alternative fuel applications are economically competitive when compared to conventional diesel power systems, considering the growing technology readiness level of fuel production and fuel cells. Overall, this study is expected to provide guidance for the utilization of alternative fuels for ships and to identify the optimal ship integrated energy systems solutions.