Water relocation in hydrogen energy transport: A prospective study

Hydrogen is widely considered a central energy carrier for future decarbonized systems; however, an important physical implication remains largely overlooked: the large-scale relocation of water inherently embedded in hydrogen production and transport. This study presents a global prospective assessment quantifying water redistribution associated with hydrogen-based energy trade using energy consumption datasets from 200 countries, combined with stoichiometric constraints and conservative efficiency assumptions. Unlike previous studies that evaluate water use in hydrogen production or energy flows separately, this approach explicitly quantifies the interregional relocation of water driven by hydrogen transport at the planetary scale. Results indicate that hydrogen-driven energy exchanges could generate measurable regional imbalances in water availability. Under conservative scenarios, the total relocated water volume may reach up to 23 times the amount required for direct human drinking water consumption and could approach regional requirements for health and hygiene based on a reference threshold of 50 L inhabitant⁻¹ day⁻¹. These findings reveal a previously unquantified constraint within the water–energy nexus and highlight the need to incorporate water relocation effects into long-term hydrogen trade planning. A sensitivity analysis using updated global datasets for the period 2019–2024 confirms the robustness of the results, with variations below 7% across all scenarios and no change in comparative behavior, reinforcing the structural nature of the identified water relocation effect. The results provide quantitative support for the development of water-positive hydrogen strategies, particularly in water-stressed exporting regions, contributing to more robust environmental and sustainability assessments of future global energy transitions.