The hydrogen-water collision: Assessing water and cooling demands for large-scale green hydrogen production in a warming climate

Hydrogen is expected to play a critical role in future energy systems, projected to have an annual demand of 401–660 Mt by 2050. With large-scale green hydrogen projects advancing in water-scarce regions like Australia, Chile, and the Middle East and North Africa, understanding water requirements for large-scale green hydrogen production is crucial. Meeting this future hydrogen demand will necessitate 4010 to 6600 GL of demineralised water annually for electrolyser feedwater if dry cooling is employed, or an additional 6015 to 19,800 GL for cooling water per year if evaporative cooling is employed. Using International Panel of Climate Change 2050 climate projections, this work evaluated the techno-economic implications of dry vs. evaporative cooling for large-scale electrolyser facilities under anticipated higher ambient temperatures. The study quantifies water demands, costs, and potential operational constraints, showing that evaporative cooling is up to 8 times cheaper to implement than dry cooling, meaning that evaporative cooling can be oversized to accommodate increased cooling demand of high temperature events at a lower cost. Furthermore, of the nations analysed herein, Chile emerged as having the lowest cost of hydrogen, owing to the lower projected ambient temperatures and frequency of high temperature events. • By 2050, global annual hydrogen demand is projected to reach 537Mt H2 . • Global annual demand for deionised water for electrolysers by 2050: 4010–6600 GL. • Water cooling for green hydrogen production can mitigate risk from high-heat events.