Comparative Life Cycle Water Use Assessment of Diverse Hydrogen Production Pathways

Hydrogen is a potential solution for hard-to-abate industries while undergoing transitioning to a net-zero economy. Low-carbon hydrogen can be produced from renewable and fossil resources by electrolysis and reforming or gasification with carbon capture by using clean electricity, respectively. This study comparatively evaluates the life cycle water use of various hydrogen production pathways, which varies with feedstock type, production technology, electricity and water supply sources, cooling technology, and production location. Among the stages across the life cycle, hydrogen plant operation and electricity supply dominate the life cycle water use for hydrogen production. The competitiveness of water footprints for electrolysis compared to reforming or gasification with carbon capture highly depends on the source of electricity supplied for hydrogen production, even in a net-zero economy. The lowest life cycle water consumption can be achieved by integrating wind-powered electrolysis with dry cooling at a hydrogen production plant. Dry cooling and alternative water sources can be employed to reduce the use of freshwater for hydrogen production. Hydrogen, water, and electricity are interlinked and should be coordinated locally to ensure sustainability in the three dimensions.