World’s first offshore green hydrogen electrolyser begins production

The world’s first site for the production of green hydrogen at sea from offshore wind power has produced its first batch of hydrogen from a floating 1MW electrolyser off the coast of France.

The 1MW “Sealhyfe” pilot project was developed by French pure hydrogen producer Lhyfe and US-based Plug Power, which supplied the electrolyser. It has the capacity to produce up to 400kgs of green hydrogen each day.

The electrolyser has been deployed off the coast of Saint-Nazaire, at first for six months on a prototype wave enegy platform near the quay, and will later be moved to a floating wind facility about 20kms off the coast.

There it will be tested for 12 months, located less than a kilometre from the floating wind turbine, fixed by a system of anchors and connected to the site’s underwater hub using an umbilical designed and dedicated for this application (energy and data transfer).

The pilot will test the systems needed to “marinise” the technology and convert power from the floating wind turbine, pumping, desalination, and purifying seawater, as well as electrolysis.

Offshore green hydrogen could reach 3GW of capacity

At the end of this 18-month demonstration pilot phase, Lhyfe expects that it will be in a position to design a more mature offshore production system and deploy on a large scale. It says there is potential of 3GW of offshore electrolyser capacity by 2030-35.

“At Lhyfe, we have only one aim: to leave a more breathable planet for our children,” said Matthieu Guesné, chairman, CEO, and founder of Lhyfe.

“This is why we once again wanted to take up a major technological challenge, to prove – by producing hydrogen at sea for the first time – that it is possible to do it as of today.”

Lhyfe and Plug have agreed to jointly develop 300MW of green hydrogen plants across Europe by 2025.

“Today’s inauguration of Sealhyfe marks a pivotal moment for Plug and Lhyfe, demonstrating that green hydrogen is possible, not just in onshore projects, but offshore too,” said Andy Marsh, the CEO of Plug.


Joshua S. Hill is a Melbourne-based journalist who has been writing about climate change, clean technology, and electric vehicles for over 15 years. He has been reporting on electric vehicles and clean technologies for Renew Economy and The Driven since 2012. His preferred mode of transport is his feet.

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