France launches its largest battery storage facility in Cernay-lès-Reims

On October 1, 2026, TagEnergy and Banque des Territoires inaugurated a large-scale battery energy storage system (BESS) in Cernay-lès-Reims, located in northeastern France. With a capacity of 240 MW and 480 MWh, the facility is currently the largest operational battery storage project in the country. It provides essential grid-balancing services to help maintain a stable and reliable electricity supply. The site is connected to the 225 kV grid managed by RTE and is expected to play a significant role in supporting the energy transition in France.

The project highlights the increasing importance of battery storage within the modern energy landscape. Since its founding in 2019, TagEnergy has expanded quickly, developing a portfolio of more than 10 GW in solar, wind, and battery storage across the UK, France, and Japan. The Cernay-lès-Reims facility is the company's first operational storage asset in France, using technology that is becoming more necessary as the demand for renewable energy grows. The site covers 3-hectare and houses 140 Tesla Megapack battery containers. Civil and electrical works were managed by the French engineering group Eiffage, with project management support provided by Tewa Solar.

This project is the result of a three-year partnership between TagEnergy and Banque des Territoires aimed at financing large-scale storage projects across France. TagEnergy remains the majority owner of the facility, while Banque des Territoires holds a 49% stake which it acquired in 2025. This joint venture reflects a broader move toward public-private partnerships to fund renewable energy infrastructure.

The impact of the facility reaches beyond immediate grid stability. By helping to integrate wind and solar power into the national grid, the project supports France's broader decarbonization goals. Early performance data has been positive; the facility reportedly fed 70.5 GWh back into the grid during its first four months of operation, completing 145 full cycles over 125 days. As the energy storage market continues to evolve, the site represents a practical step toward addressing the challenges of grid reliability.

The success of the Cernay-lès-Reims project may serve as a model for future energy storage initiatives in France. As the country continues to invest in renewable technologies, the partnership between TagEnergy and Banque des Territoires is expected to lead to further developments in the sector. The ongoing operation and performance of the site will be monitored closely, as the results are likely to influence investment strategies and funding for similar projects in the future.