French utility Engie has signed a contract with Kallista Energy to manage the commercial optimisation of a 120-megawatt/240-megawatt-hour battery energy storage system (BESS) currently under construction in Saleux, northern France.
Under the agreement, Engie will be responsible for optimising the battery’s performance, including managing charging and discharging cycles and providing services to the national electricity grid. The commercial operations will be managed by Engie for a period of seven years, while Kallista Energy will oversee the technical operations of the site.
The project, which marks Engie’s first major battery storage optimisation contract in France, is being financed by Kallista Energy in collaboration with Landesbank Saar (SAAR-LB) and BNP Paribas. Envision Energy is contracted for the turnkey construction of the facility and will also handle long-term maintenance and battery recycling.
Construction of the Saleux site in the Somme department of Hauts-de-France has already commenced and is scheduled for completion by the end of 2026.
Kallista Energy Group President Johann Tardy said the company had engaged with experienced partners across all aspects of the project. “This collaboration with Engie on battery optimisation gives us the assurance that the Saleux site will be used to its maximum capacity to help accelerate the electrification of our uses,” he said.
Henri Domenanch, director of energy management activities at Engie, said the partnership reflects the company’s broader strategy to support grid flexibility and renewable energy integration. “By optimising the operation of the Saleux site, Engie is demonstrating its ability to enhance the flexibility of the electricity grid while supporting the integration of renewable energies,” he said.
