Electrolyzer Water Demand Planner

Size the water supply for PEM or alkaline electrolyzers by combining your hydrogen target, specific water consumption, utilisation, recycle rate, and purification losses. The planner outputs daily makeup volumes, flow rates, and annual cost at your chosen tariff.

Target hydrogen output at nameplate.
Litres of water consumed per kilogram H₂ (include polishing losses).
Optional. Default 90% utilisation if blank.
Optional. Default 0% recovery.
Optional. Default 5% to cover filters, blowdown, and sampling.
Optional. Default $3.00 per cubic metre.

Outputs provide preliminary engineering values. Validate against vendor datasheets and pilot runs before sizing treatment trains.

Examples

  • 1,200 kg/day nameplate, 10.5 L/kg, 85% capacity, 30% recycle, 8% reject, $2.80/m³ ⇒ Fresh intake 7,754.04 L/day (323.09 L/h, 5.38 L/min), purge 856.80 L/day, monthly 232,621.20 L, annual 2,830,224.60 L, water cost $21.71/day and $7,924.63/year.
  • 500 kg/day, 9.0 L/kg, default capacity 90%, no recycle, 5% reject, $3.00/m³ ⇒ Fresh intake 4,050.00 L/day (168.75 L/h, 2.81 L/min), purge 202.50 L/day, monthly 121,500.00 L, annual 1,478,250.00 L, cost $12.15/day and $4,434.75/year.

FAQ

How do I change units to gallons?

Multiply the displayed litres by 0.2642 to obtain US gallons. A future update will expose a unit toggle.

Does recycle rate include condensate recovery?

Yes. Enter the combined percentage of process water returned from condensate polishers, catholyte loops, or other reclaim systems.

What purity level does the calculator assume?

Use your process spec (e.g., ASTM Type II or deionised <1 µS/cm) when selecting the base litres per kilogram. Higher purity increases the reject percentage.

Additional Information

  • The theoretical minimum water consumption is 9 L/kg H₂; practical plants often range 9–11 L/kg before recycle.
  • Capacity factor scales the daily hydrogen target to reflect actual operating hours over a year.
  • Purification reject covers deioniser backwash, filtration blowdown, and sample draws; adjust upward for harsher feedwater.
  • Fresh intake represents the external makeup water after recycle, while purge volume highlights wastewater that must be treated or discharged.

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