Green hydrogen and its supply chain. A critical assessment of the environmental impacts

Green hydrogen produced via electrolysis powered by renewables can greatly contribute to achieving carbon neutrality. The analysis of 35 papers reporting the life cycle assessment (LCA) of green hydrogen supply chains confirms the lower greenhouse gas (GHG) emissions with respect to other hydrogen forms and conventional fossil fuel and carbon systems. However, the global warming potential of green hydrogen worsens if grid electricity is used to back up renewable sources. Green hydrogen is also responsible for water consumption and for land use, while offshore platforms may be responsible for the loss of marine biodiversity. Another potential environmental hotspot is the depletion of rare metals and critical materials employed in the electrolyzer and in the power generation plants. This issue is exacerbated by the lack of information about the management of the end-of-life stage of this equipment. Notably, the delivery along the supply chain is responsible for hydrogen leaks, whose environmental consequences are still uncertain.