How much hydrogen does a 100 MW electrolyser produce?
A 100 MW electrolyser operating at full input and an assumed system electricity use of 55 kWh/kg H₂ produces about 1,818 kg/h, or 43.6 tpd during continuous operation. At 50% annual utilization, estimated output is 7,964 tpa. MW describes input power; annual hydrogen output also depends on operating hours and electricity use per kilogram.
Start with electrical input and specific consumption
For an electrolyser rated by electrical input, multiply MW by 1,000 to obtain kW, then divide by specific electricity consumption in kWh/kg H₂. The result is hydrogen production in kg/h at that input level. This calculation needs a power rating and a consumption figure measured at the same equipment boundary.
At the illustrative 55 kWh/kg H₂ used here, each 1 MW of continuous electrical input supports about 18.2 kg/h. A 100 MW plant supports about 1,818 kg/h. A lower consumption value gives more hydrogen for the same electrical input. These are H2Prism screening calculations, not operating measurements or supplier guarantees.
Est. hydrogen output (kg/h) = electrolyser input (MW) × 1,000 ÷ system electricity use (kWh/kg H₂)
Use annual equivalent full-load hours for tpa
Multiply the full-load hourly output by annual equivalent full-load hours. For this constant-consumption example, those hours equal 8,760 multiplied by the annual utilization fraction. A utilization of 50% therefore means 4,380 equivalent full-load hours. Actual dispatch can include more clock hours at part load.
Dividing kilograms by 1,000 converts the result to metric tonnes. The two factors of 1,000 cancel when MW is converted directly to tpa with the formula below. The table assumes 55 kWh/kg H₂ at a consistent system boundary, a 365-day year and no separately applied hydrogen losses.
Est. annual output (tpa) = input capacity (MW) × 8,760 × annual utilization ÷ system electricity use (kWh/kg H₂)
| Electrolyser input (MW) | 30% utilization | 50% utilization | 70% utilization | 90% utilization |
|---|---|---|---|---|
| 1 | 47.8 | 79.6 | 111 | 143 |
| 10 | 478 | 796 | 1,115 | 1,433 |
| 100 | 4,778 | 7,964 | 11,149 | 14,335 |
H2Prism calculation from illustrative assumptions. Whole tonnes are shown above 100 tpa. Utilization is applied once.
A daily nameplate rate and an annual average answer different questions
At 55 kWh/kg H₂, the 100 MW example gives 43.6 tpd if it runs continuously at full input for a day. Multiplying that rate by 365 assumes continuous full-load operation all year. At 50% annual utilization, average output across the calendar year is 21.8 tpd and annual output is 7,964 tpa.
When a project states both a daily production capacity and an annual target, establish whether the daily figure is a full-load rating or a calendar-day average before comparing them. Keep separate columns for nameplate rate, modeled annual output and measured production.
Keep stack, system and renewable-generation MW separate
An electrolyser's DC stack rating and an AC system rating cover different equipment. Consumption may include rectification and auxiliary equipment or only the stack. DOE's PEM study explicitly distinguishes these boundaries. Use matched input and consumption boundaries before converting power into hydrogen output.
The MW of a wind or solar farm describes generation capacity. Its hourly output, curtailment, storage, grid purchases and the relative sizes of the generator and electrolyser determine the electrolyser's operation. Adding generation MW to electrolyser MW does not produce a meaningful hydrogen-capacity total. Similarly, a battery's MWh describes stored energy; battery MW describes power.
Sources
DOE
Clean Hydrogen Production Cost Scenarios with PEM Electrolyzer Technology, Record 24005
Pages 2 and 8: system boundary and stack/system consumption
As of: 2024-05-20
Last confirmed: 2026-10-18
Read a project announcement at the right stage
Plug's October 2025 Sines announcement reported delivery of a first 10 MW array toward a planned 100 MW installation at Galp's refinery. The delivered module and the total planned plant describe different scopes. Counting the first array as the complete 100 MW installation would overstate the equipment reported delivered in that announcement.
For a project comparison, record the delivered module separately from the whole plant. Use subsequent commissioning or production evidence to establish operation and realized output. The cited equipment-delivery announcement provides a historical example of how to read the figures; it is not a statement of the refinery's current operating status.
Sources
Plug
Plug Power Delivers First Electrolyzer for 100MW Green Hydrogen Project at Galp's Sines Refinery
Page date October 01, 2025 and first three release paragraphs
As of: 2025-10-01
Last confirmed: 2026-10-18
Compare projects with a small set of consistent fields
Read the electrical input boundary, hydrogen output unit, plant phase, utilization assumption and product specification together. Confirm whether annual output is a design projection or an operating measurement. Keep hydrogen tonnes separate from ammonia or other derivative tonnes.
For an initial comparison, use MW to compare electrolyser input ratings and tpa to compare hydrogen output on the same annual basis. Preserve the original measurement for each project. If you estimate an output, keep the assumed consumption and operating hours with the calculation rather than turning the estimate into a sourced project value.
Carry the production case into a cost calculation
The Hydrogen Price Calculator lets you define capacity, capacity factor and system electricity use for an electrolysis case. Match those boundaries to your project, then examine the modeled annual output. If the model also includes availability, degradation or hydrogen losses, its net annual output can differ from this simplified constant-consumption calculation.
Use the companion electricity-cost guide to check the power contribution per kilogram. A larger electrolyser changes total output, but cost per kilogram changes only through the assumptions that change with size, utilization or equipment performance. Keep those assumptions explicit when comparing projects or supply options.
Common questions
How much hydrogen does a 1 MW electrolyser produce?
At an assumed 55 kWh/kg H₂, 1 MW of continuous input supports about 18.2 kg/h. At 50% annual utilization over a 365-day year, estimated annual output is 79.6 tpa before separately modeled losses.
How do I convert MW into tonnes of hydrogen per year?
For matched system boundaries and constant consumption, multiply MW by 8,760 and the annual utilization fraction, then divide by kWh/kg H₂. The result is tpa. Utilization of 50% is entered as 0.50.
Are MW of wind and MW of electrolysis directly comparable?
Wind MW is a generation rating and electrolyser MW is an input rating. The generation profile and plant configuration determine how much electricity reaches electrolysis and how much hydrogen is produced.
Do announced tonnes per year prove actual production?
A design or target figure describes expected output under stated assumptions. Actual production requires operating evidence for the relevant period and facility.