There is growing interest worldwide in the idea of hydrogen production offshore using electricity generated by offshore wind turbines, “allowing all countries with a coastline to access renewable green hydrogen, produced locally,” says France-based green hydrogen start-up Lhyfe, which describes itself as a “producer of hydrogen whose production emits zero CO2

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World first for Lhyfe at Saint-Nazaire. (Credit: Lhyfe)

Lhyfe is claiming a world first, with hydrogen production on a floating platform in the port of Saint-Nazaire. “Until now, no one has ever produced hydrogen at sea,” the company says. The platform was inaugurated on 22 September 2022.

Following six months of green hydrogen production trials at the quay, the floating platform will be taken out into the Atlantic, about 20km off the coast of Le Croisic, to demonstrate fully automated hydrogen production in hostile marine conditions, using power from a floating wind turbine.

The sea trials are expected to last about 12 months.

The hydrogen production equipment – which has the capacity to produce up to 400 kg of renewable green hydrogen per day, equivalent to 1 MW of power – is housed in what Lhyfe calls its Sealhyfe platform. This has been installed on the WAVEGEM wave energy platform developed by Geps Techno.

Lhyfe is making use of facilities provided by the SEM-REV offshore testing site, operated by the French engineering school Centrale Nantes. The floating turbine to be used to power the Sealhyfe platform was installed within the SEM-REV testing site in 2018.

The platform will be installed less than a kilometre from the floating wind turbine, fixed to the seabed by a system of anchors and connected to the SEM-REV site’s underwater hub using an umbilical specifically designed for this application (energy and data transfer).

The test programme encompasses all stages of hydrogen production at sea, including: making use of power from the floating wind turbine; pumping, desalinating and purifying seawater; and electrolysis.

Among the issues to be addressed will be the effects of platform motion on the hydrogen production system, environmental stresses deriving from being located at sea (premature ageing, corrosion, temperature variations, etc) and the challenges of operating in an isolated environment, with the Sealhyfe having to operate fully automatically, without the physical intervention of an operator, except for scheduled maintenance periods.

At the end of the trial, Lhyfe says it will have a substantial volume of data, which should allow it to design mature offshore production systems, and “to deploy robust and proven technologies on a large scale, in keeping with the EU’s objective of producing 10 million tonnes a year of renewable hydrogen by 2030.”

The electrolyser was supplied and optimised for these “exceptional operating conditions” by Plug Power. Plug and Lhyfe say they have “developed the first electrolyser capable of operating on a floating platform under extreme conditions”, with Plug’s EX-425D 1 MW electrolyser “marinised to meet acceleration, tilt and other marine specifications.”

Lhyfe and Plug, having initiated a strategic relationship in October 2021, have also executed an MoU to jointly develop 300 MW of green hydrogen plants across Europe by 2025. In September 2022, Plug announced a deal with Lhyfe to provide 50 MW of PEM electrolysers for green hydrogen production, the company’s largest multi-site order in Europe.

For the Sealhyfe Saint-Nazaire project, Lhyfe also acknowledges the role of the following French offshore and marine renewable energy players: Chantiers de l’Atlantique, for enhancing the resilience of the system to environmental stress, and work on ventilation systems and electrical architecture; Geps Techno and Eiffage Energie Systèmes for integration with the WAVEGEN platform and the naval architecture of the latter, engineered for the particularly stormy sea conditions at the site; Port of Saint-Nazaire, facilitator of Sealhyfe assembly and testing; and Kraken Subsea Solutions, which participated in the design of the underwater electrical connections to renewable marine energy producers on the SEM-REV platform.

Sealhyfe has had support from the French energy and environment agency ADEME and the Pays de la Loire Region.

Dolphyn progresses

Meanwhile, looking to the coast of Aberdeen, Principle Power has been contracted by ERM to advance the FEED (front-end engineering design) for a wind-to-hydrogen Dolphyn 10 MW demonstrator project off the coast of Aberdeen. The contract was signed after ERM Dolphyn was awarded £8.62 million of funding from the UK government, via the Low Carbon Hydrogen Supply 2 Competition.

ERM’s Dolphyn (Deepwater Offshore Local Production of HYdrogeN) is a conceptual design for producing green hydrogen at a large scale from floating offshore wind. The ERM Dolphyn concept employs a modular design integrating electrolysis and a wind turbine on a moored floating semi-submersible platform based upon the proven WindFloat technology developed by Principle Power. ERM and Principle Power have been collaborating on the development of decentralised hydrogen production opportunities since 2019.

“It is now established that to meet net-zero ambitions…hydrogen from offshore floating wind needs to be a significant component in any viable long-term solution for heat, electricity generation, and transport,” said David Caine, partner at ERM.

The 10 MW demonstrator, aiming for operation in late 2025, is seen as a key step in proving the Dolphyn concept prior to commercial-scale deployment. Commercial-scale projects (300 MW +) are under development and expected to be in operation pre-2030, followed by large-scale (GW) deployment post-2030.

ERM’s Dolphyn development is envisaged as a core project for the UK’s “hydrogen coast” strategy.

Getting the Dolphyn concept to utility-scale will require advancements in modularisation and industrialisation, the developers note, for which Principle Power is leveraging its 15 years of experience and lessons learned in pre-commercial projects such as WindFloat Atlantic (25 MW, Portugal) and KOWL (50 MW, UK) to “streamline everything from design concept to manufacturing to installation and load-out.”

This article first appeared in Modern Power Systems magazine.