Thirsty clean energy: localized water stress and hydro-ecological tradeoffs in green hydrogen expansion

Green hydrogen is central to global decarbonization, yet its rapid expansion exposes a severe spatial contradiction: the regions possessing optimal renewable energy potential are overwhelmingly the planet’s most water-stressed and ecologically fragile landscapes. This review critically examines the localized hydro-ecological tradeoffs of mega-scale electrolysis across arid export corridors in Australia, Chile, and North Africa. Moving beyond theoretical stoichiometry, the analysis deconstructs the true operational water footprint of commercial electrolysis and evaluates cascading secondary risks, including marine ecotoxicity from desalination brine, fossil aquifer depletion, and spatial ecosystem fragmentation. Prevailing sustainability frameworks are critiqued for their fatal overreliance on carbon-centric metrics, which systematically externalize ecological carrying capacities and socio-economic water justice, risking a new paradigm of green extractivism. Finally, the review outlines fact-based technological and regulatory horizons—including direct seawater splitting, circular wastewater integration, and planetary-boundary-informed zoning—necessary to decouple the clean energy transition from localized hydrological collapse.