Water system and water saving outlook of large-scale renewable energy electrolysis hydrogen production plant

The large-scale integrated hydrogen production model has become an important way to solve the problem of the “wind and solar curtailment” and promote the development of hydrogen energy industry. Whether it is pure water electrolysis or alkaline electrolysis, water is a core element for raw material supply and a key medium for equipment cooling. In actual operations, there are significant regional differences in water intake and consumption for electrolysis-based hydrogen production projects, especially in arid regions of Northwest China. Utilizing scientific water management and advanced water-saving technologies is strategically important for promoting the sustainable development of green hydrogen industries. This paper systematically analyzed the water quality indicators and process design requirements for water systems in electrolysis-based hydrogen production plants, including water generation systems, circulating cooling water systems, chilled water systems, and wastewater treatment systems. The water usage and discharge volumes, water migration paths, water balance diagrams, and water-saving measures in a specific hydrogen production plant case study were also examined. Combining water treatment technologies, water management, and advanced hydrogen production techniques, this paper proposed a comprehensive hydrogen-water co-production technology approach that integrated hydrogen production with wastewater treatment and deep water conservation in hydrogen production plants, as well as future technological development directions.