The short answer
Alkaline electrolysers cost less to install: in 2024, between €1,819/kW (IEA figures converted to euros by ACER) and €2,310/kW (European Hydrogen Observatory), against €2,365–2,503/kW for PEM. Depending on the source, PEM is 8% to 30% more expensive per kilowatt.
In exchange, PEM responds faster to changes in load, which matters when it runs directly on solar or wind power. The electricity use of the two is similar. In the cost per kilogram the difference is a few tenths of a euro: €0.5–0.6/kg more for PEM in the cases published by ACER and by the Observatory.
Two technologies, one sentence each
Alkaline
The most mature and most widely installed technology; nickel or steel electrodes in a liquid alkaline electrolyte.
PEM (proton exchange membrane)
A solid polymer membrane with iridium and platinum catalysts; quick to respond to changes in load.
Solid oxide (SOEC)
Runs at high temperature and gains efficiency when it can use waste heat; still at a pre-commercial stage.
Anion exchange membrane (AEM)
The newest; it aims to combine cheap materials, without noble metals, with a fast response.
What each one costs to install
The two most cited references for 2024 agree on the order and differ on the amount. The IEA, in the figures that ACER converts to 2024 euros, puts the installed system at €1,819/kW for alkaline and €2,365/kW for PEM. The European Hydrogen Observatory, from a survey of developers for a 100 MW plant, at €2,310/kW and €2,503/kW.
They do not measure exactly the same thing: the Observatory also counts land, grid connection fees, permits and contingencies. Read each figure with its source, and use the one whose scope matches your budget.
€/kW
Each bar comes from the source in its label; the two sources measure slightly different scopes. See the sources at the end.
And the Chinese electrolyser?
China has nearly 60% of the world’s electrolyser manufacturing capacity, according to the IEA. Installed outside China, with transport and tariffs, a Chinese electrolyser cost USD 1,500–2,400/kW in 2024 by the IEA’s estimate. The equipment is only part of the installed cost: engineering, construction and the rest of the plant count too.
Worldwide, alkaline leads, both in manufacturing capacity and in installed plants, according to Spain’s Observatorio Tecnológico del Hidrógeno and the IEA. In Europe the balance tips the other way: PEM accounts for 51–54% of manufacturing capacity and alkaline for 43.5–44%, according to the European Hydrogen Observatory and Hydrogen Europe.
Electricity use, stack life and flexibility
Electricity use
Similar. The IEA describes their efficiency as comparable and the Observatorio Tecnológico del Hidrógeno gives overlapping ranges; the European Hydrogen Observatory assumes a slightly lower consumption for alkaline in its calculator.
Stack life
Longer for alkaline. The stack, the pile of cells, is the part that wears out and is replaced during the plant’s life; an alkaline stack lasts 10,000 to 20,000 operating hours longer than a PEM stack, according to the University of Freiburg and the European Hydrogen Observatory.
Flexibility
Faster for PEM. PEM follows changes in load quickly, which suits power that comes and goes with the sun and the wind; alkaline responds more slowly, although the IEA notes that both can be designed to run directly on variable renewable power.
Materials: iridium and platinum, or nickel
PEM needs iridium at the anode and platinum at the cathode: scarce noble metals that manufacturers are trying to use less of. Alkaline works with nickel or steel electrodes, abundant and inexpensive materials, and with a corrosive liquid electrolyte.
What changes in the cost per kilogram
Less than the price per kilowatt suggests. With the same assumptions for both technologies, the cases published by ACER (2024) and by the European Hydrogen Observatory (2025), both run with the Observatory’s calculator, put PEM €0.5–0.6/kg above alkaline.
Electricity and operating hours weigh more than the technology: at 52 kWh/kg, every €10/MWh on the power price adds about €0.5/kg, as much as the whole gap between the two. That is why it pays to run both options with the data of your own project.
The figures at a glance
| Figure | Value and source |
|---|---|
| Installed alkaline, 2024 | €1,819/kW (IEA, via ACER); €2,310/kW (EHO, 100 MW plant) |
| Installed PEM, 2024 | €2,365/kW (IEA, via ACER); €2,503/kW (EHO, 100 MW plant) |
| PEM over alkaline, per kW | +8% (EHO) to +30% (IEA) |
| PEM over alkaline, per kg | +€0.5–0.6/kg (ACER, 2024; EHO, 2025) |
| Chinese electrolyser installed outside China, 2024 | USD 1,500–2,400/kW (IEA) |
| Electrolyser manufacturing in Europe | PEM 51–54%; alkaline 43.5–44% (EHO, end of 2025; Hydrogen Europe, 2025) |
| Stack life | 10,000–20,000 hours longer for alkaline (University of Freiburg; EHO) |
A check you can do yourself
Spread the extra investment over the hydrogen it produces. With a 6% cost of capital and 25 years, the defaults of the Observatory’s calculator, each euro invested per kW costs about €0.078 a year. At 4,000 hours and 52 kWh/kg, each kW produces about 77 kg of hydrogen a year.
The Observatory’s gap of €193/kW adds 193 × 0.078 ÷ 77 ≈ €0.20/kg; the €546/kW gap in the IEA figures, ≈ €0.55/kg. That is capital only: the rest of the difference comes from the other costs, operation and maintenance, stack replacements and electricity.
Frequently asked questions
Which is better for green hydrogen, PEM or alkaline?
Neither in every case. Alkaline costs less per kilowatt and its stack lasts longer; PEM responds faster to variable power. In the published cost cases the gap is €0.5–0.6/kg, so a project’s power supply and operating hours usually weigh more than the technology.
Why is a PEM electrolyser more expensive?
It uses a polymer membrane and catalysts of scarce noble metals, iridium and platinum, where alkaline uses nickel or steel. In 2024 an installed PEM system cost €2,365–2,503/kW, against €1,819–2,310/kW for alkaline.
How long does an electrolyser stack last?
Tens of thousands of operating hours, and longer for alkaline than for PEM: 10,000 to 20,000 hours more, depending on the source. When it wears out it is replaced, and that replacement is part of the cost per kilogram.
Can I compare both technologies in the GaugeH2 calculator?
Yes. The calculator lets you choose PEM, alkaline, solid oxide or AEM. For PEM and alkaline it starts from the IEA installed cost for 2024 (€2,365 and €1,819/kW), and every input can be changed and is printed with its origin.
Sources
- IEA — Global Hydrogen Review 2025, executive summary (September 2025)
- ACER — Current and forecasted investment cost for electrolysers as reported in IEA’s Global Hydrogen Review 2022–2025 (CHEST, 28 November 2025)
- European Hydrogen Observatory — The European hydrogen market landscape (November 2025)
- European Hydrogen Observatory — Electrolyser cost, data and assumptions (consulted 9 November 2026)
- European Hydrogen Observatory — Levelised Cost of Hydrogen calculator manual, 2025 update (May 2025)
- ACER — Breakdown of hydrogen production costs for alkaline and PEM electrolysers (CHEST, 18 November 2024)
- IEA — Electrolysers (consulted 9 November 2026)
- GCN — IEA notes China’s electrolyzer edge, SE Asia demand (4 October 2025)
- Observatorio Tecnológico del Hidrógeno — Renewable hydrogen production via electrolysis: state-of-the-art and future prospects (1 December 2025)
- Universität Freiburg (M. Geller) — Electrolyzer Supply Chains (December 2025)
- Hydrogen Europe — Electrolyser manufacturing: where does Europe stand? (2025)
- HydroNews — Only 500 MW of operational electrolysis in the EU by the end of 2025 (24 February 2026)