System design and comparative analysis of PEMFC and H2-ICE propulsion systems for a 2000-m3 liquefied hydrogen carrier: a case study of ocean and coastal routes

• Two hydrogen propulsion systems are assessed for a Korean 2,000 m 3 LH 2 test carrier. • LCC model combines PEMFC degradation with IMO GHG intensity rules. • H 2 -ICE LCC is 4.2% lower than PEMFC for a 2000-m 3 LH 2 carrier. • PEMFC demonstrates superior regulatory resilience, generating USD 9.5 million in surplus unit (SU) revenue compared to USD 1.4 million for H 2 -ICE. • Economic parity can be achieved at an SU price of USD 280 per ton CO 2 eq if the CAPEX ratio is reduced to 1.5. Despite growing interest in hydrogen propulsion, limited studies have accounted for regulatory evolution and fuel cell stack degradation in system-level economic assessments. This study evaluates the techno-economic performance of proton-exchange membrane fuel cell (PEMFC) and hydrogen internal combustion engine (H 2 -ICE) propulsion systems for a Korean 2000-m 3 -class liquefied hydrogen test carrier. Using Aspen HYSYS and a dynamic life cycle cost framework, the research considers PEMFC stack degradation modeling and International Maritime Organization (IMO) greenhouse-gas fuel intensity regulations. The results indicate that the H2-ICE system maintains a 4.2% LCC advantage over the PEMFC system. However, PEMFC exhibits superior regulatory resilience, generating USD 9.5 million in surplus unit (SU) revenue, compared with USD 1.4 million for H 2 -ICE. Crossover-point analysis shows that while economic parity currently requires high SU prices (USD 600–700 per ton CO 2 eq), reducing the CAPEX ratio to 1.5 can achieve parity at USD 280 per ton CO 2 eq. This suggests that the economic barrier to a green transition can be effectively overcome through manufacturing-driven CAPEX reductions combined with carbon pricing mechanisms. Consequently, PEMFC systems remain an indispensable, long-term solution for maritime sustainability and meeting stringent IMO net-zero targets.