Design performance analysis of a turbocharged solid oxide fuel cell integrated with internal combustion engine for maritime applications

As the importance of decarbonizing transport sectors becomes increasingly urgent, the International Maritime Organization published its revised strategy in 2023 to cut GHG emissions in the maritime field, aiming to net zero in 2050. In this context, investigating innovative high-efficiency technologies is attracting attention for onboard applications. The present study proposes an innovative configuration, based on the integration of internal combustion engine (ICE) and pressurized solid oxide fuel cell (SOFC), both fed by natural gas stored onboard a short-sea ferry (1.2 MW installed power). During the cruise, the traditional engine is employed for propulsion, while the SOFC covers the hotel load and a limited amount of the propulsion load: the integration of the two energy systems is the main focus of this study. The off-gases from the pressurized SOFC are employed to provide part of the energy input to the ICE, optimizing efficiency. A steady-state off-design model was developed in a Matlab–Simulink environment to analyze the performance of the whole hybrid system at different fuel utilization factors (UF) and part-load conditions of SOFC. Although the SOFC module efficiency improves at higher UF (80 %) and part-load conditions, the analysis results show that the optimal hybrid system performance is obtained for lower UF (60 %) at SOFC full load conditions. Based on the findings, the operating conditions for the SOFC can be determined to obtain optimal performance for the hybrid SOFC-ICE system.