Optimization design of marine solid oxide fuel cell/ internal combustion engine hybrid power system considering degradation

The integration of solid oxide fuel cell (SOFC) with internal combustion engine (ICE) in hybrid power systems has demonstrated high efficiency and low emissions. However, the long-term performance impacts due to SOFC degradation in hybrid systems are not well understood. This study presents the optimization design and performance evaluation of a marine SOFC-ICE hybrid power system, considering performance degradation. The results indicate that the SOFC-ICE system achieves a 10.72 % efficiency improvement compared to a standalone SOFC system. Furthermore, the ICE can compensate for the additional power output required when the fuel cell's performance degrades, thereby extending the operational lifespan of the hybrid system. The power rating of the ICE significantly affects the SOFC's operational lifespan and the overall system's economic viability. For a fuel cell stack with a power of 320 kW, the optimal system performance is achieved when the ICE power rating is 250 kW, resulting in a levelized cost of energy of 0.168 $/kWh and carbon emissions of 375.81 g/kWh. Finally, the study on the impact of power ratio between the SOFC and ICE indicate that the space occupied by the power system compartment will approximately double when the initial power ratio of SOFC to ICE is 1:2.