The photo is sourced from blog.topsoe.com

Solid oxide electrolysers use heat and electricity to split water molecules into oxygen and hydrogen at the temperature above 1,000 degrees Celsius. Electrolysers of this type use less electricity than alkaline or proto-exchange membrane (PEM) plants. However, they require an external source of thermal energy that’s why the Topsoe customers may include companies seeking solution of the of waste heat recovery problem, including producers of ammonia and hydrogen. The company plans to produce annually electrolysers with total capacity of 500 GW at its Herning plant but the site capacity may be expanded to 5 GW in the future.

While alkaline electrolysers use a liquid electrolyte solution to hydrogen production, proton exchange membrane electrolysers use a solid polymer electrolyte. However, both types of units operate at the temperatures not higher than 80 degrees Celsius, which is their main difference from solid oxide electrolysers. However, the last of the three technologies is not widespread enough. According to the International Energy Agency (IEA), the 2020 global capacity of electrolysers was 286 MW, over 90% of which were alkaline units (176 MW) and PEM electrolysers (89 MW).

As Topsoe estimates, the Herning plant, if expanded to 5 GW capacity per year, would become the world’s largest electrolyser production site. It will compete with British ITM and German ThyssenKrupp, which are going to increase the capacity of their own electrolyser sites to 5 GW per year in the next few years.