Lhyfe has inaugurated its offshore renewable green H₂ production demonstrator in Saint-Nazaire. This is the first time in the world that renewable H₂ will be produced at sea. The Sealhyfe platform, which seeks to pave the way for a new energy paradigm awaited worldwide, is starting an 18-month experimental period, at quay then off the coast of Le Croisic, on the offshore testing site (SEM-REV) operated by French engineering school Centrale Nantes.

Producing H₂ at sea: A global challenge to be tackled

Around the world, the race for H₂ is on and the development of offshore wind farms is booming. Lhyfe – which inaugurated the world’s first site to produce H₂ from onshore wind turbines in September 2021 and which is currently preparing to deploy its solutions Europe-wide – is convinced of the central role offshore must play in the massification of renewable green H2 production.

Producing H₂ using offshore wind turbines could allow all countries with a coastline to access renewable green H₂, produced locally, beyond the horizon line, and in industrial quantities, to decarbonize transportation and industry. However, until now, no one has ever produced H₂ at sea. It is to prove that it is now possible that Lhyfe is today taking on the great offshore challenge.

A series of major and unprecedented challenges

Through this pilot site, Lhyfe will produce the first kilograms of renewable green H₂ at quay and then at sea, operating automatically, in the most extreme conditions. The company has voluntarily set the bar high by installing its production unit on a floating platform, connected to a floating wind turbine.

The Sealhyfe platform must therefore meet several major and unprecedented challenges, including:

• Performing all stages of H₂ production at sea, i.e., converting the electrical voltage from the floating wind turbine, pumping, desalinating and purifying seawater, and breaking the water molecules via electrolysis to obtain renewable green H₂
• Managing the effects on the system of the platform’s motion: list, accelerations, swinging movements
• Enduring environmental stress: Sealhyfe will have to survive the premature ageing of its parts (corrosion, impacts, temperature variations)
• Operating in an isolated environment: the platform must operate fully automatically, without the physical intervention of an operator, except for scheduled maintenance periods which have been optimally integrated from the design phase.

A demonstrator developed with top experts

To achieve this technological feat, Lhyfe relied on the facilities of the offshore testing site, SEM-REV, operated by Centrale Nantes.

• The production unit was installed on the WAVEGEM wave energy platform developed by Geps Techno.
• At the end of the quayside test phase, the Sealhyfe platform will integrate the SEM-REV offshore testing area, off the coast of Le Croisic, about 20 kilometers from the coast.
• The device will then be supplied with electricity by the pioneering floating wind turbine installed within the offshore test site in 2018 and still unique in France today.

The electrolyzer was supplied and optimized for these exceptional operating conditions by Plug Power, one of the market leaders that is strongly engaged in the offshore route. Together, Plug and Lhyfe have developed the first electrolyzer capable of operating on a floating platform.

The project also benefited from the expertise of French offshore and marine renewable energy players:

• Chantiers de l’atlantique for enhancing the resilience of the system to environmental stress, ventilation systems and the electrical architecture of the system,
• Geps Techno and Eiffage Energie Systèmes for the system’s integration on a platform and the naval architecture of the latter, specifically for the particularly stormy sea conditions of the site,
• The Port of Saint-Nazaire, facilitator of Sealhyfe’s assembly and testing, and,
• Kraken subsea solutions, which participated in the design of the underwater electrical connection to the renewable marine energies produced on the SEM-REV platform.

A multi-phase trial

A first six-month trial phase is being started at quay, in the port of Saint-Nazaire, to obtain initial reference measurements and test all the systems (desalination and cooling systems, stack behavior, remote control, energy management, resistance to environmental conditions, etc.).

At the end of this first stage, Sealhyfe will spend a period of 12 months off the Atlantic coast. It will be installed less than a kilometer from the floating wind turbine, fixed to the ground 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).

At the end of this trial, Lhyfe 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 to produce 10 MMtpy of renewable H₂ by 2030.

Sealhyfe has the capacity to produce up to 400 kg of renewable green H₂ a day, equivalent to 1MW of power. By 2030-2035, offshore could represent an additional installed capacity of around 3 GW for Lhyfe. Sealhyfe has had support from the French energy and environment agency ADEME and the Pays de la Loire Region.

Matthieu Guesné, Chairman and CEO and founder of Lhyfe said, “At Lhyfe, we have only one aim: to leave a more breathable planet for our children. Therefore, 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. By paving the way for the mass production of renewable hydrogen at sea, Sealhyfe is fully in line with the EU’s strategy to deploy an offshore hydrogen chain and wishes to help build the energy sovereignty of countries.”