A review on global warming potential, challenges and opportunities of renewable hydrogen production technologies

This review compares global warming potential of renewable hydrogen production technologies including wind- and solar PV-powered water electrolysis, biomass gasification and biogas reforming based on 64 hydrogen production cases compiled from the literature. Unlike many previous studies, this review discusses the cases from various countries, while selecting the production technologies that have potential of commercialisation. Among the four reviewed technologies, wind electrolysis performed the best in global warming impacts (1.29 kg CO₂ eq/kg H₂), whereas biogas reforming technology performed the worst (3.61 kg CO₂ eq/kg H₂). Key factors that contributed to most of the impacts were found to be materials used for construction of wind- and solar- electricity generation system for both wind- and solar PV-powered electrolysis, and energy consumption during gasification processes for biomass gasification, while methane leakage during biogas production had the highest contribution to the impacts of biogas reforming cases. On average, the renewable hydrogen cases demonstrated 68–92% lower global warming potential when compared to conventional coal gasification and natural gas steam methane reforming systems. Increasing demand for renewable hydrogen and possibility of hydrogen being integrated into existing natural gas networks highlight the important role of renewable hydrogen production in the future.