A 20 MWp floating solar project completed by Générale du Solaire and Ciel & Terre

21.01.2025

The construction of a 20 MWp floating solar project in Leutenheim (Bas-Rhin/France), is now complete. This is the first large-scale floating solar power project in Alsace and the first floating solar power plant to be built by Générale du Solaire, a French independent producer of renewable electricity that already owns more than 450 MWp of photovoltaic power plants in France.

Leutenheim floating PV plant was completed thanks to a partnership between Générale du Solaire and Ciel & Terre, which offers innovative floating solar solutions based on feedback from more than 325 projects installed on all types of artificial ponds.

The largest floating solar project in Alsace rehabilitates a former gravel pit

After 5 years of development, 6 months of works and the active support of the local authority, which owns the site, the construction of Leutenheim floating photovoltaic project is now complete. The 21 750 MWh of electricity which will be produced annually represents the equivalent of the energy needs of 7250 homes (Consumption per household: based on consumption of 3000 kWh/year per household – excluding heating). per year (excluding heating) and avoids the emission of the equivalent of 1392 tonnes of CO₂ (Tonne of CO₂ saved: based on 64 g.CO₂ eq /kWh) per year. To date, this floating installation is the first of its kind in Alsace. It is also the first to be commissioned by Générale du Solaire, which is currently developing several other projects of this type.

Leutenheim floating PV plant will make the most of a gravel pit in an area that is no longer being used. The 2-island plant is helping rehabilitate the industrial pond, turning it into a source of renewable energy production. Floating solar power is compatible with commercial and industrial activities such as mining and quarrying. Each site has its own specific characteristics which Ciel & Terre responds to with the best-suiting technical solutions.

A premiere in Eastern France thanks to a major partnership between Générale du Solaire and Ciel & Terre

2024 was a particularly busy year for Ciel & Terre in France, with the construction of 3 floating solar projects, equivalent to more than 100 MWp – Leutenheim being one of those projects. The project was initiated by Générale du Solaire, which took charge of the development, construction, financing, and operation of the solar farm and co-constructed it from scratch with local authorities. The Group Générale du Solaire called on Ciel & Terre, a long-term expert in floating solar solutions, to take into account all of the requirements and technical implications for this type of project. This included the design, the management of the installation, and the anchoring of the floating structure.

Solar projects have their raison d'être everywhere in France. In order to guarantee optimum yield from the plant, particularly in less sunny regions such as Alsace, it is vital to optimize the overall design of the plant. The technical solution implemented by Ciel & Terre to maximize the yield of Leutenheim floatovoltaic project is the new version of its Hydrelio technology, the aiR Optim.

The aiR Optim is the result of the 14 years of experience and innovation by Ciel & Terre’s R&D teams. It optimizes plant operation thanks to a new float design that facilitates cable management and the installation of junction boxes and/or string inverters while simplifying maintenance work as well. The technology is compatible with virtually all PV modules on the market. This solution is also highly modular, offering a wide range of configurations to suit each project and its performance requirements.

Anchoring of FPV plants: a crucial technical challenge that needs to be mastered

The reliability of the anchoring system is crucial as it guarantees the correct positioning of the floating solar plant on its reservoir and its durability. The system at Leutenheim was quite complex to implement as the mooring lines for the two islands intersect at the inter-island zone, representing a challenge in both the design and construction phases. The site conditions also made this challenge even greater: with water levels varying considerably due to heavy rainfall, sometimes reaching 2.5 m, the construction workshops had to be constantly readapted to the site.

Ciel & Terre anticipated the anchoring challenges at a very early stage. Each stage, from the design phase right through to the installation of the anchors, required high rigor, particularly during the technical site studies. Their local design office carried out specific technical studies that enabled them to choose the anchoring solution that best fitted the needs of the project, the resistance of which was checked by an inspection office. Particular care was also taken during construction to ensure that the islands could cohabit on the water without any risk of drifting. Générale du Solaire's Leutenheim floating solar power plant has a bright future ahead of it.