Abstract
This study uses comparative life cycle assessment to compare the life cycle impacts of three power systems for a 10.5-m Norwegian gillnet fishing vessel: a conventional diesel–mechanical (DMS), a diesel–battery parallel hybrid (PHS), and a hydrogen fuel cell-battery series hybrid (SHS) system. Results show that direct emissions are dominated by combustion-related impacts, while component manufacturing drives toxicity and resource categories. The PHS reduces global warming potential (GWP) by 28%, and the SHS by up to 91% compared to the DMS when powered by low-carbon electricity and green hydrogen from electrolysis in Norway. However, both alternatives shift burdens towards manufacturing-related impact categories. Sensitivity analysis highlights the critical role of electricity and hydrogen supply pathways: fossil-based inputs can erase benefits, while localised low-carbon electrolysis enables slight improvements. The findings stress that battery and fuel cell systems can reduce fishing vessel emissions meaningfully only when coupled with clean energy supply chains.