Q0044
Current water electrolysers typically use about 50–55 kWh of electricity to produce one kilogram of hydrogen before some auxiliary, compression and conversion loads. At that rate, 100,000 tonnes a year requires roughly 5–5.5 TWh of electricity for electrolysis alone, equivalent to an average continuous load of about 570–630 MW. The renewable plant needed will be larger because solar, hydro and other resources do not produce at full nameplate output all year.
Large hydrogen projects can become some of the biggest electricity users in a region. Their renewable demand affects generation build-out, grid connections, land, water, system balancing and whether clean power remains available for homes, industry and direct electrification.
| Hydrogen output | Electrolyser electricity at 50–55 kWh/kg | Average continuous load | |---|---:|---:| | 1 tonne per day | 50–55 MWh per day | 2.1–2.3 MW | | 10,000 tonnes per year | 0.50–0.55 TWh per year | 57–63 MW | | 100,000 tonnes per year | 5.0–5.5 TWh per year | 571–628 MW | | 1 million tonnes per year | 50–55 TWh per year | 5.7–6.3 GW |
These figures cover electrolysis and are rounded screening estimates. Water purification, pumps, cooling, hydrogen drying, compression, liquefaction or conversion into ammonia, methanol or another carrier require additional energy.
A continuously supplied electrolyser needs firm electricity. A solar-only project requires considerably more nameplate capacity than its average load and must accept variable hydrogen output or add grid supply, storage or complementary generation. Hydro or a diversified renewable portfolio can provide a different utilisation profile.
At 100,000 tonnes a year, a change of 5 kWh/kg changes annual electricity demand by about 0.5 TWh. Equipment efficiency, part-load performance, degradation and auxiliary consumption therefore matter at national planning scale.
The chemical reaction consumes about nine litres of water per kilogram of hydrogen. Actual plant withdrawals are higher after purification losses and cooling, and the appropriate figure depends on plant design and whether water is recycled. Coastal desalination adds infrastructure and energy but may avoid competition for freshwater.
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