Green hydrogen — made by splitting water with renewable electricity — is central to decarbonising industry and heavy transport. The electrochemical cell needs large DC current at low voltage, so the power-electronics that feed it are a critical, often underappreciated, part of the system. Their efficiency directly sets the cost of the hydrogen produced.
Working principle
Renewable generation provides AC (or DC from solar). A rectifier / DC power supply — typically a thyristor rectifier or a modern IGBT/SiC active front-end — converts this into the precisely-controlled, high-current DC the electrolyzer stack requires. The supply must handle the variability of wind and solar, ramp quickly, and maintain power quality on the grid side. A controller regulates current to the stack to set the hydrogen production rate.
| Type | Operating temp | Supply characteristic |
|---|---|---|
| Alkaline | 60–90 °C | Mature, slower dynamics |
| PEM | 50–80 °C | Fast ramp, suits renewables |
| Solid oxide (SOEC) | 700–850 °C | High efficiency, thermal mgmt |
Key requirementBecause renewables are intermittent, the supply must follow rapid power swings; PEM electrolyzers are favoured for their fast dynamic response, but they stress the power electronics accordingly.
Applications
- Industrial-scale green-hydrogen plants and hydrogen hubs
- Power-to-X: ammonia, e-fuels and steel decarbonisation
- Renewable curtailment absorption and seasonal storage
References & further reading
- Buttler & Spliethoff, “Current status of water electrolysis for energy storage and power-to-gas,” Renewable & Sustainable Energy Reviews, 2018.
- Carmo et al., “A comprehensive review on PEM water electrolysis,” Int. J. Hydrogen Energy, 2013.
- IRENA, “Green Hydrogen Cost Reduction,” 2020.