High Spatiotemporal Availability of Hydrogen by Electrolysis of Municipal Reclaimed Water in China
Weixiang Chao, Xiuling Yan, Lu Lü
Abstract
Large-scale electrolytic H 2 production requires a stable electricity supply, sustainable water availability, and proximity to the H 2 end-user. However, these elements often exhibit spatiotemporal mismatches in China. Reclaimed water, an unconventional water resource generated by municipal wastewater treatment plants, is widely distributed across China. This study conducted a life-cycle assessment of H 2 production from reclaimed water in China, focusing on potential capacity, cost, and carbon emissions. The results were compared with those using tap water and seawater. Even when prioritized for ecological and municipal reuse, reclaimed water demonstrated significant H 2 production capacity (95.7–213.1 Mt/year between 2021 and 2060), attributable to its proximity to critical resources and H 2 markets. This capacity could meet China’s annual H 2 demand (33.4–130.9 Mt/year) while achieving provincial self-sufficiency. By contrast, H 2 production capacity using tap water and seawater is substantially lower (19.8–79.1 Mt/year). Currently, H 2 production from reclaimed water exhibits cost and carbon emissions comparable to those of conventional electrolytic routes. However, advancements in electrolyzer efficiency and grid decarbonization could reduce these metrics to 4.0 ± 0.5 USD/kg H 2 and 4.99 ± 0.05 kg CO 2 -eq/kg H 2 by 2050, making it competitive with fossil-derived H 2 (∼4.3 USD/kg H 2 ) while meeting green H 2 threshold (∼4.9 kg CO 2 -eq/kg H 2 ).