The first offshore wind turbine in France

Today, FLOATGEN is the only offshore wind turbine, whether fixed or floating, to be installed in France. The project named Floatgen, managed by Ideol, Centrale Nantes and Bouygues TP is a 2 MW floating wind turbine and is the first offshore wind turbine in France.

Construction work on the floating foundation took place between 2016 and 2017 in Saint Nazaire. It was inaugurated on 13 October 2017 and was installed on the Centrale Nantes offshore test site, SEM-REV, in April 2018 to perform all tests in real conditions. The Floatgen wind turbine has been exporting kWh to the electricity grid since September 2018.

Innovation at all levels

Innovation is present throughout the project, whether it be the concept of a floating foundation in a square ring shape, or the offshore test site itself, or the type of concrete used for building the floater, or the material used for the mooring lines.

The Centrale Nantes SEM-REV offshore test site, on which the wind turbine will be installed, is a research facility of international scope. It enables full deployment of prototypes which capture ocean energy (wind, waves) in real conditions at sea. Hence, researchers and professionals have access to the necessary tools to test prototypes before the commercial stage.

Key project data


Floater of 36 meters wide and of 9.5 m height (7.5 m draft). Equipped with the Ideaol's Damping Pool ® system and built in prestressed reinforced concrete by Bouygues TP


Model Vestas V80 2MW
Rotor diameter: 80 meters
Mast height including transition piece: 60 meters


Semi-taut mooring
6 synthetic fiber lines (nylon)


Installation on the first French offshore test site dedicated to multi-technologies and connected to the grid: a Centrale Nantes offshore test site, named SEM-REV


33 meters deep
12 nautical miles from the shore (22 km)


Particularly harsh conditions with maximum wave height (Hmax) of 16 meters

The floating foundation

June 2017
After a few months of construction in the Penhoët basin (Saint-Nazaire), the floating foundation that will equip the first offshore wind turbine in France was launched in September. The three assembled barges on which the floating foundation was built were towed to the Joubert lock, a dry-dock marking the entrance to the port of Saint-Nazaire. After the barges were immerged, the concrete hull was floated with perfect control. It was then towed towards the Quai des Charbonniers to await the addition of another part (a steel part at the interface between the floating foundation and the mast) and then the wind turbine.

The wind turbine

The Vestas 2 MW V80 that will be installed on the floater was unloaded on Saint-Nazaire harbour in June 2016. It will be slightly modified before being installed along the dock on the transition piece.

The mooring system

The elements of the anchoring system were assembled and installed on the Centrale Nantes test site, SEM-REV, in june 2017.

This very innovative system, developed by the start-up Ideol in collaboration with Centrale Nantes, consists in particular of 6 synthetic mooring lines (nylon) - a first for permanent anchoring of this dimension.

Installation on the test site

Three deep sea tugs were deployed during this delicate operation. Setting off late afternoon on Sunday 29th April, it took them about a day to transport the wind turbine to the SEM-REV test site. An additional three to four days are necessary for docking and connection to the export cable, which connects the wind turbine to the power grid onshore.
Floatgen will be tested under real operating conditions for 2 years. During the testing phase, the electricity produced by the turbine will be injected into the French power grid and Floatgen will supply enough electricity to meet the needs of a city the size of Le Croisic.

Floating exported kWh to the electricity grid

The connection of the electricity export cable and a final series of tests carried out in recent days enabled the Floatgen wind turbine, which is installed 22 km off Le Croisic (Loire-Atlantique), to become fully operational on Tuesday 18 September 2018.

For Centrale Nantes, this is the first production tool and the first injection of electricity into its export cable at its SEM-REV test site dedicated to marine renewable energies (third installation after tests on acoustic sensors and cable weights).

With its connection to the grid, SEM-REV will enable the wind turbine to supply electricity to 5000 inhabitants.

The testing period of the floating wind turbine designed for this project will be financed partially within the FORESEA project and will enable analysis of:
  • the impact of the floating wind turbine and its mooring system on the environment
  • the quality and quantity of electricity produced by the wind turbine
  • system performance
  • exploitation and maintenance costs

Floatgen: starting point of a serial deployment

The Floatgen project, the first wind turbine in France and first demonstrator of the floating foundation technology developed by Ideol, already provides and will continue to provide unique practical feedback to the partners of the consortium. Lessons will be learnt on building methods, installation and exploitation of the floating system and will be used as a commercial example for export. In July 2016, the French government selected a consortium led by Quadran with the Ideol floater foundation and Bouygues TP know-how, for the construction of a first offshore floating wind farm in the Mediterranean sea (4 units will be installed off Gruissan, one of the best sites for wind resources in Europe). This will be known as the EOLMED project.
Published on July 3, 2017 Updated on April 22, 2024