Major progress for 850 MWh of battery storage projects in France

Entech and Eiffage Energie Systèmes will build two battery energy storage systems in France with a combined capacity of 200 MW/400 MWh. The projects are scheduled for commissioning in the first half of 2027 and are being developed on behalf of a grid connection infrastructure developer.

The contract covers the construction of two 100 MW / 200 MWh storage units, including battery supply, as well as the associated high-voltage substation to connect the facilities to the RTE-managed 225 kV transmission network. It also includes operation and maintenance services for 15 years.

Earlier in January, the same partnership won another tender for a storage plant and high-voltage substation for an independent solar power producer. This installation features a 50 MW battery energy storage system (BESS) capable of storing energy during periods of grid overcapacity and injecting up to 100 MWh back into the grid once or twice daily for approximately 15 years.

The plant is composed of six replicable “islands”, each linked to the high-voltage substation. Every island contains four 5 MWh battery containers and two 40-foot Medium Voltage Station (MVS) containers. Energy from the batteries is converted through DC/AC power converters, stepped up via 33 kV transformers, and then fed back into the RTE grid.

Meanwhile, French developer Acacia has begun construction on its first two BESS projects in France, following financial close. The projects, totaling 200 MW / 400 MWh, are located in the Hauts-de-France and Centre-Val de Loire regions.

The projects are being delivered in partnership with Luxembourg-based Eren Groupe, which became a shareholder in Acacia in 2025. Together, the two companies partnered on a 500 MW BESS portfolio in France in June 2025.

Acacia has also signed a ten-year operations contract with Swiss optimizer BKW for the management of the two batteries. Both projects are scheduled for commissioning in 2027.