The first commercial-scale use of high-temperature solid-oxide electrolysers (SOE) is set for a biofuel refinery in the Netherlands.

SOE technology offers highly efficient green-hydrogen production — when using waste heat from nearby sources, it can produce four to six times as much H2 output per kWh as other types of (unheated) electrolysers, according to consultancy Element Energy.

To date, SOE electrolysers have only been deployed in pilot projects.

The MULTIPLHY project, to be built at Neste’s biorefinery in Rotterdam, will use a 2.6MW SOE electrolyser, built by German manufacturer Sunfire, which will be able to produce 60kg of hydrogen per hour — a similar rate to the most efficient alkaline electrolysers.

The project partners — Engie, Sunfire, Neste (the world’s leading provider of biodiesel and green aviation fuel), French research organization CEA and Luxembourg-based plant builder Paul Wurth — say they hope to produce about 960 tonnes of green hydrogen by the end of 2024. But they have not revealed when the plant will be built or completed.

Other details — such as where the renewable energy will come from or whether waste heat will be part of the process ­— have also not been disclosed.

MULTIPLHY will, however, receive €6.9m of funding from the EU, via the Horizon 2020 programme.

“This project shows the great progress being made in bringing our green hydrogen production technologies to the next level and paving the readiness for a further scale up to 100 MW,” said Sunfire managing director Nils Aldag.

Lars Peter Lindfors, senior vice-president of innovation at Neste, added: “Demonstrating green hydrogen production at our Rotterdam refinery enables us to drive the development of new sustainable technologies aiming at decreasing the carbon footprint of our customers.”

Why hydrogen is important for the energy transition

Hydrogen is a zero-emissions fuel that can be used for energy storage, heat production, long-distance transport, and to decarbonise polluting industrial processes such as steel and cement production. Hydrogen can either be burned to generate energy or turned into electricity directly using a fuel cell.

More than 95% of the hydrogen produced today is derived from unabated fossil fuels (natural gas or coal), resulting in nine to 12 tonnes of CO2 emissions for every tonne of H2. This is known as grey hydrogen.

However, 'green hydrogen' can be produced with zero emissions by using renewable electricity to split water molecules into H2 and oxygen inside a machine called an electrolyser; a process known as electrolysis.

Or the CO2 emissions from natural-gas-based H2 production can be captured and stored, resulting in what is known as blue hydrogen. Strictly speaking, this would be classed as low-carbon hydrogen as not all the CO2 from the production process can be captured.