FOS3F: Floating Foundation Factory in Fos-Sur-Mer

A concrete serial production line, bringing together BW Ideol and NGE.

The Fos3F (Floating Foundation Factory) project  aims to build and operate a concrete floater factory in Fos-sur-Mer, on the DEOS platform of the Grand Port Maritime de Marseille.

BW Ideol and NGE, France's fourth-largest construction group, are equal partners in the development of the manufacturing line. Both companies submitted a joint bid to the Grand Port Maritime de Marseille (GPMM) call for projects for the concession of the DEOS site, covering 30 hectares of platform area backed by 400 usable linear metres of quay in Fos-sur-Mer.

Local production of concrete floaters, close to the sites of the future floating wind farms, is a strategic lever to reduce both the cost and the carbon footprint of the floaters, while maximising socio-economic benefits for the territories concerned.

Meeting the needs of floating wind in the Mediterranean

The FOS3F project is fully relevant at a time when the French government launched the AO10 tender in June 2026, bringing the cumulative development of floating wind in France to more than 5 GW, including 3.7 GW on the Mediterranean seaboard. It entails the supply of more than 200 floating foundations between 2030 and 2037.

A feasibility study, funded by ADEME under France 2030 and completed at the end of 2024, confirmed the economic competitiveness, the positive impact on local industry and the socio-economic benefits of such a concrete floater factory. 

The Méditerranée Grand Large project, in which BW Ideol Projects Company is a shareholder, is one of the floating wind farms planned off Fos-sur-Mer. 

An industrial turning point for floating wind

The planned production line in Fos-sur-Mer is dedicated to the fabrication of concrete floaters based on BW Ideol's innovative and patented Damping Pool® design, the only floating foundation concept proven at sea on two continents and engineered to meet the requirements of both current (15 MW+) and next-generation (20 MW+) floating wind projects.

The feasibility study confirmed the robustness of local concrete floater production, outperforming the other execution schemes available today. It delivers unrivalled competitiveness by reducing logistics costs and risks and by maximising local economic benefits.

Ideally located on the Mediterranean coast, this serial production line will meet the needs of various floating projects in France, Spain (east coast), Italy and Greece, contributing to the growth of renewable energy in Southern Europe.

Local, low-carbon sourcing

The project follows a sustainable and responsible approach towards the environment. It plans to prioritise short supply chains, sourcing materials directly from local cement plants and quarries, and producing a low-carbon concrete mix on site. All components of the floating foundations are recyclable to more than 95%.

Rail as the priority transport mode

The project aims to prioritise rail for the transport of materials, thereby reducing the carbon footprint associated with their delivery. Favouring rail also helps reduce road traffic in an area already congested by lorries, limiting the impact on local residents.

Reduced CO₂ emissions

Finally, by using concrete rather than steel, this production line will also generate substantial savings in CO₂ emissions, with an estimated 30% reduction compared with steel floaters manufactured abroad. The impact on the carbon footprint is even more significant when considering the construction phase alone: the FOS3F project demonstrates a 45% reduction in carbon emissions compared with a steel semi-submersible foundation manufactured in Asia and shipped to Europe for final assembly.

A positive energy transition for local territories

The establishment of this serial production line in Fos-sur-Mer is fully in line with the European energy transition strategy. By producing locally the floaters required for wind farms, the project reduces dependence on imports and strengthens the competitiveness of renewable energy solutions across the Mediterranean region.

The Fos-sur-Mer production line will also be a driver for the local economy. It will create 1,300 direct jobs, both skilled and unskilled, contributing to an energy transition with positive impacts for the territory.

Financing

The project has been selected by the European Commission for Grant Agreement Preparation by the Innovation Fund, for a grant of up to 74 million euros. This funding comes in addition to a green industry investment tax credit (C3IV) of up to 52 million euros, bringing the total secured public funding to 126 million euros.

An exclusive partnership with NGE

On 23 July 2026, BW Ideol and NGE, France's fourth-largest construction group, announced the signature of an exclusive partnership agreement for the floating wind market in the Mediterranean. NGE brings its recognised expertise in the design and delivery of complex infrastructure projects, particularly in civil engineering.

This partnership builds on the strategic agreement concluded with the Holcim group in December 2025 for the supply of innovative materials, including low-carbon concrete.

Project milestones

• End of 2024: the ADEME-funded feasibility study, supported by France 2030, confirms the economic and industrial viability of a concrete floater factory at Fos-sur-Mer.
• November 2025: the project is selected by the European Commission for Grant Agreement Preparation under the Innovation Fund, for a grant of up to €74 million.
• December 2025: strategic agreement with Holcim for the supply of innovative materials, including low-carbon concrete.
• 19 March 2026: the Innovation Fund Grant Agreement is signed. Combined with the C3IV tax credit of up to €52 million, total secured public funding reaches €126 million.
• June 2026: the French government launches the AO10 tender, bringing cumulative floating wind development in France to more than 5 GW.
• 23 July 2026: BW Ideol and NGE announce an exclusive partnership and a joint bid to the GPMM call for projects for the concession of the DEOS site. 

Adaptability and replicability of the production line

This production line is designed to be easily adaptable to the requirements of larger floating foundations, compatible with turbines of 20 MW and above. Requiring minimal port works and limited prerequisites, this manufacturing line can be implemented in many ports.

It can be easily replicated in other ports, and a twin project, Ardersier3F, is being developed by BW Ideol at the Port of Ardersier in Scotland, applying the same manufacturing blueprint to the Scottish and North Sea market. 

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Climate, Infrastructure and Environment Executive Agency (CINEA). Neither the European Union nor the granting authority can be held responsible for them.