The 2.6MW Sunfire-made electrolyser operates at up to 850ºC to produce over 60kg of green hydrogen per hour, making it what project partners call the “world’s largest” multi-megawatt high-temperature electrolyser in an industrial environment.

Hydrogen generated by the system is being used to replace grey hydrogen at the site to help reduce greenhouse gas emissions.

Installed as part of the EU-funded MultiPLHY project by Neste, Sunfire, French research organisation CEA, and energy firm Engie, the electrolyser uses heat produced by the refinery to reduce the amount of electricity required for hydrogen production.

“This installation is the largest of its kind in an industrial environment and represents a significant milestone for both the technology and the clean hydrogen sector,” said Mirela Atanasio, Head of Unit Operations and Communication at EU research and funding organisation the Clean Hydrogen Partnership.

It comes as one of the first field deployments of Sunfire’s solid oxide technology, after a series of large-scale alkaline system installations.

Sunfire claims heat utilisation could see its system reach efficiencies of 84% LHV – far beyond the typical stack LHV efficiencies of 60–65% for low-temperature electrolysis.

Despite its potential, SOEC remains a nascent technology, with no large-scale systems operating globally.

However, CEO Nils Aldag said the project proved the technology could be integrated into industrial environments.

Now the partners will carry out a test programme to validate the technology’s performance.