Environmental implications of solid oxide fuel cell system for hydrogen sustainability

Hydrogen, known for its high energy content and clean combustion, is promising in the energy transition. This study explores the environmental impact of a solid oxide fuel cell (SOFC) system. 1 kg of hydrogen production at 1 bar serves as the functional unit. The SOFC system generates hydrogen, electricity, and heat across five modes. Results indicate that the SOFC system achieves a global warming potential of 0.17–9.50 kg CO 2 -eq/FU using the system expansion method. Regional analysis shows that areas with high renewable electricity shares experience increased CO 2 emissions due to functional unit decision. The exergy allocation method is less sensitive to electricity sources and seasonal emission profiles than system expansion. Comparing eight production routes, the SOFC system using biomethane (−5.46 kg CO 2 -eq/FU) outperforms steam methane reforming (11 kg CO 2 -eq/FU) and biomass gasification (1.49 kg CO 2 -eq/FU). These insights are valuable for advancing renewable energy initiatives and effectively mitigating climate change. • Study a novel SOFC system design that generates electricity, hydrogen, and heat. • Details LCA results for climate change, ecosystem quality and human health impacts. • Evaluates emissions using different electricity sources, fuel types, and profiles. • Highlights benefits of system expansion and exergy allocation in LCA multifunctionality. • Provides new insight on hydrogen categorization against conventional methods.