Published the 26/01/2024

  • After 14 months of testing, including in particularly tough conditions, Sealhyfe was brought back with its full production capacity intact and with a wealth of insights that are already benefiting Lhyfe’s onshore and offshore projects.
  • Lhyfe, which is already a pioneer in the production of hydrogen on land, is opening up a major new stage in the global hydrogen industry, and has confirmed its operational excellence.

Nantes (France), 26/01/2024 –7:30 am – Lhyfe (EURONEXT: LHYFE), one of the world’s pioneers in the production of green and renewable hydrogen, has announced that the operating results of its offshore hydrogen production pilot platform, Sealhyfe, which returned to dock in November 2023, confirm that the initial objectives have been met and enable another step forward for the company.

Right: Sealhyfe, an offshore hydrogen production pilot (Lhyfe) equipped with a Plug electrolyser, on the WAVEGEM platform (GEPS Techno),

Left: the FLOATGEN floating wind turbine (BW Ideol) on the SEM-REV sea trials site (Centrale Nantes/OPEN-C) ©Lhyfe


A world first for offshore hydrogen production

The Sealhyfe project, equipped with a 1 MW electrolyser supplied by Plug, aimed to demonstrate that producing hydrogen offshore from renewable energy sources is already a reality. More specifically, the experiment aimed to:

  • Demonstrate Lhyfe’s ability to operate an industrial-scale production unit (1 MW) in an isolated environment,
  • Prove the reliability of the electrolysis technology in harsh environmental conditions that are representative of the operating conditions of its future large-scale offshore sites,
  • Provide a database of operating data that can be used to optimise and make production processes more reliable, and to test the technologies employed with a view to scaling them up to sites with ten times and then 100 times greater capacity.

A range of measurement and data collection instruments were installed on board Sealhyfe to ensure precise management and control of all the production unit’s parameters from September 2022 to November 2023, first at the quayside and then at sea.


Review of test results and analysis of equipment after 14 months of trials

  • System responsiveness and versatility: As offshore hydrogen production is particularly relevant for providing services to the electricity grid, Lhyfe repeatedly tested the system’s versatility and responsiveness in a wide range of configurations. The experiment also confirmed the system’s ability to manage the variability of wind power in specific offshore conditions. The electrolysis system was operated as part of the planned research tests, including at maximum production capacity. The performance achieved was as high as on land, confirming the reliability of the installation.
  • Robustness: Throughout the trial, the production system equipment designed by Lhyfe was tested in extreme conditions for platform movement management, environmental stress, etc. In particular, Sealhyfe was confronted with five significant storms, including Ciaran, which swept along the Atlantic coast in October 2023, with waves over 10 metres high and winds of over 150 kph. A complete analysis of the production system once it was back on land confirmed that all equipment had returned unharmed with its production capacity intact.
  • Equipment and system optimisation: Throughout the experiment, on-board and remotely-controlled measuring instruments were used to identify ways of optimising the efficiency and reliability of Lhyfe’s production units – including safety systems, electrical architecture, automation, fluid and stock management, etc. – for its other projects.
  • Remote control: The quayside benchmark testing phase helped to de-risk the project. The vast majority of impacts specific to offshore hydrogen production were identified and reduced. The site was then operated exclusively remotely from Lhyfe’s control centre, using supervision and control tools specifically developed by the company. The experiment made it possible to validate the software and algorithms for producing green and renewable hydrogen, and to reduce the number of operations required in the marine environment. In total, Lhyfe carried out fewer than ten maintenance operations and the system was operated for 70% of the operating time.
  • Regulatory developments: As part of this world first, Lhyfe also worked with the French authorities to define the operating rules for a green hydrogen production unit operating within an urban, industrial and port environment, and also capable of operating in the open sea.

Overall, the Sealhyfe project enabled Lhyfe to develop its expertise in handling the constraints associated with offshore industrial deployment, thanks in particular to its experience integrating an isolated, offshore plant on a floating barge at sea.


Next steps: HOPE and the ramp-up onshore

The results of this experiment are already being incorporated into the HOPE project, which represents the second stage in Lhyfe’s offshore ambitions. This project, which Lhyfe presented with a consortium of nine partners, was selected by the European Commission for a €20 million grant as part of the Clean Hydrogen Partnership, along with an additional €13 million grant from the Belgian government. With HOPE, Lhyfe and its partners are changing scale and aiming to commercialise green hydrogen produced offshore. From 2026, this unprecedentedly large-scale project (10 MW) will be able to produce up to 4 tonnes per day of green hydrogen at sea, which will be exported ashore by pipeline, and then compressed and delivered to customers.

The Sealhyfe project will also ensure that the production processes at Lhyfe’s land-based sites are reliable and optimised from the outset, so that they can be ramped up quickly and progressively. Lhyfe’s ambition is to have a production capacity of up to 22 tonnes of green hydrogen per day by the end of 2024 and up to 80 tonnes per day by 2026.

Matthieu Guesné, Founder and CEO of Lhyfe said: “The positive results of the Sealhyfe trial and the lessons we have learned from it represent a major new step for Lhyfe. We can now draw on our experience of three onshore sites and one offshore site to design our next green hydrogen production sites. This bolsters our expertise and the confidence of our partners, and supports the entire industry, because Sealhyfe has made offshore hydrogen production a reality”.


For an interview with the spokespersons, please contact the press department.

Click to access the Lhyfe Media Kit (press kit and visuals)


About Lhyfe

Lhyfe is a European group devoted to energy transition, and a producer and supplier of green and renewable hydrogen. Its production sites and portfolio of projects intend to provide access to green and renewable hydrogen in industrial quantities, and enable the creation of a virtuous energy model capable of decarbonising entire sectors of industry and transport.

In 2021, Lhyfe inaugurated the first industrial-scale green hydrogen production plant in the world to be interconnected with a wind farm. In 2022, Lhyfe inaugurated the first offshore green hydrogen production pilot platform in the world.

Lhyfe is represented in 11 European countries and had 149 staff at the end of 2022. The company is listed on the Euronext market in Paris (ISIN: FR0014009YQ1 – LHYFE).


About Plug

Plug is building an end-to-end green hydrogen ecosystem (production, storage, delivery) to help its customers achieve their business goals and decarbonize the economy. In creating the first commercially viable market for hydrogen fuel cell technology, the company has deployed more than 60,000 fuel cell systems and more than 185 fuelling stations, which is more than anyone else in the world. Plug is also the largest buyer of liquid hydrogen. With ambitions to build and operate a green hydrogen highway across North America and Europe, Plug is building a state-of-the-art Gigafactory to produce electrolysers and fuel cells, as well as several green hydrogen production plants that will produce 500 tonnes of liquid green hydrogen per day by 2025. Plug will provide its green hydrogen solutions directly to its customers and through joint venture partners across multiple industries, including handling, e-mobility, energy production and industrial applications. For more information visit




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