Environmental impacts of fuel cell use in deep-sea shipping towards 2050

Fuel cells have the potential to reduce greenhouse gas (GHG) emissions from deep-sea shipping. To fully understand the environmental impacts of integrating fuel cells into deep-sea ships, this study evaluates the life cycle environmental impacts from 2020 to 2050 for two leading fuel cell systems: liquid hydrogen with proton exchange membrane fuel cells (liquid-H 2 PEMFC) and liquid ammonia with solid oxide fuel cells (liquid-NH 3 SOFC). The study covers various factors, including changes in cargo capacity, operation modes, developments in hydrogen production and electricity decarbonization. We examine two energy scenarios developed by the International Energy Agency: the Stated Policies Scenario (STEPS) and the Net Zero Emissions by 2050 Scenario (NZE). Our findings reveal that, under different ranges and speeds, the liquid-H 2 PEMFC results in a 2% increase to a 10% decrease in cargo weight, while the liquid-NH 3 SOFC leads to a 4%–23% decrease. By 2050, under the NZE scenario, liquid-H 2 PEMFC and liquid-NH 3 SOFC can reduce GHG emissions per tonne-nautical mile by 69%–75% and 65%–71%, respectively, compared to traditional ships. The use of fuel cells also introduces environmental trade-offs. This assessment can help policymakers gain a more comprehensive understanding of the role of fuel cells in reducing GHG emissions in deep-sea shipping and underscores the potential environmental challenges associated with their large-scale deployment in the future. • The cargo capacity change affected by fuel cell propulsion systems is assessed. • The long-term life cycle environmental impacts of fuel cell use in deep-sea shipping are quantified. • Fuel cell decarbonization potential in shipping hinges on how clean the hydrogen supply is. • Fuel cell use in deep-sea shipping can induce new environmental burdens.