Technology
Green hydrogen is projected to be a cornerstone of Europe's energy transition, with the EU targeting 10 million tonnes of domestic production by 2030. What most hydrogen project developers overlook is that every kilogram of hydrogen requires 9-15 liters of ultra-pure water as feed — and the quality requirements are more demanding than most realize.
Both PEM and alkaline electrolyzers are extremely sensitive to water quality. Impurities in the feed water cause:
The typical specification is conductivity below 1 µS/cm (ideally < 0.1 µS/cm), with strict limits on chloride, silica, TOC, and individual metal ions.
A typical electrolyzer feed water system includes multimedia filtration, activated carbon, double-pass RO, and EDI (electrodeionization) or mixed-bed polishing. For seawater or brackish water sources, additional SWRO or NF stages are required upstream.
A 100 MW electrolyzer producing 2,000 kg/h of hydrogen consumes approximately 20-30 m³/h of ultra-pure water. At gigawatt scale, water supply becomes a critical infrastructure question — especially for projects in water-stressed regions like North Africa, the Middle East, or Southern Europe.
Stoichiometrically, producing 1 kg of hydrogen requires 9 liters of pure water. In practice, accounting for RO recovery rates (75-85%), cooling water, and losses, the total raw water demand is 20-30 liters per kg of hydrogen. A 1 GW electrolyzer facility needs approximately 3,000-5,000 m³/day of raw water — equivalent to a small town's water supply.
Not directly — seawater must be desalinated and polished to ultra-pure standards before entering the electrolyzer. Direct seawater electrolysis is an active research field but is not commercially viable at scale. Current projects near coastlines use SWRO desalination followed by conventional ultra-pure water polishing trains.
Water supply is your foundation. Request a RIEFILT Water Assessment — we evaluate your raw water source, design the optimal treatment train for your electrolyzer specifications, and structure the water supply as a BOOT contract so you can focus on hydrogen production, not water infrastructure.
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