Multi-Fuel SOFC System Modeling for Ship Propulsion: Comparative Performance Analysis and Feasibility Assessment of Ammonia, Methanol and Hydrogen as Marine Fuels

To reduce fossil fuel dependency in shipping, adopting alternative fuels and innovative propulsion systems is essential. Solid Oxide Fuel Cells (SOFC), powered by hydrogen carriers, represent a promising solution. This study investigates a multi-fuel SOFC system for ocean-going vessels, capable of operating with ammonia, methanol, or hydrogen, thus enhancing bunkering flexibility. A thermodynamic model is developed to simulate the performance of a 3 kW small-scale system, subsequently scaling up to a 10 MW configuration to meet the power demand of a container ship used as the case study. Results show that methanol is the most efficient fueling option, reaching a system efficiency of 58% while ammonia and hydrogen reach slightly lower values of about 55% and 51%, respectively, due to higher auxiliary power consumption. To assess technical feasibility, two installation scenarios are considered for accommodating multiple fuel tanks. The first scenario seeks the optimal fuel share equivalent to the diesel tank’s chemical energy (17.6 GWh), minimizing mass increase. The second scenario optimizes the fuel share within the available tank volume (1646 m3), again, minimizing mass penalties. In both cases, feasibility results have highlighted that changes are needed in terms of cargo reduction, equal to 20.3%, or, alternatively, in terms of lower autonomy with an increase in refueling stops. These issues can be mitigated by the benefits of increased bunkering flexibility.