Exploring the Water Footprint of “Green” Hydrogen for Power Generation in California: Equity Implications, Pitfalls, and Open Questions

Many have hailed “green” hydrogen gas as a versatile, carbon-free replacement for fossil fuels. However, environmental justice advocates, academics, and other stakeholders have raised concerns about the equity and justice implications of expanding hydrogen’s role in the energy system. One such concern is that producing green hydrogen requires substantial amounts of highly purified water — a scarce resource in drought-prone California. In this report, we review unanswered questions about hydrogen’s water footprint in California, focusing on hydrogen combustion for power generation. We discuss potential water-related pitfalls, challenges, and open questions surrounding green hydrogen in California. Using simple calculations, we sketch the potential water footprint of green hydrogen production under different demand scenarios and assumptions. Based on estimates from the literature and published projections for hydrogen demand, we conservatively estimate that hydrogen production for California will require between 230,000 and 390,000 acre-feet of high-quality water annually as of 2045. While this represents a modest impact on statewide water demand, it could have significant effects at the local level. With limited public information about hydrogen plans in the state, our examination left us with more questions than answers. Fully assessing the on-the-ground impacts will require information on project locations, water sources, source quality, and the methods and cost of purifying the water for each production site. More publicly available information and analysis are necessary to prove that green hydrogen can be implemented without mismanaging public resources and deepening environmental injustices, with the burden of proof resting on hydrogen proponents. Local and state leaders must proceed with caution and commit to protecting against these potential negative outcomes while rapidly transitioning energy sources.