A Review of Life Cycle Assessment of Carbon – Water – Energy of Hydrogen Production Systems

The hydrogen (H₂) economy is seen as a crucial pathway for decarbonizing the energy system, with green H₂ playing a key role as an energy carrier in this transition. The growing interest in H₂ comes from its versatility—it can serve as a raw material, and various technologies allow it to be produced from a wide range of resources. However, environmental impacts of H₂ production have primarily focused on greenhouse gas (GHG) emissions, despite other environmental aspects being equally relevant in the context of a sustainable energy transition. Recently, Life Cycle Assessment (LCA) studies of H₂ supply chains have become more common. This paper aims to contribute to developing a database by comparing different H₂ production pathways considering three environmental indicators: global warming potential, energy performance, and water consumption, from an LCA perspective.