Envision Energy is to supply a 193MW/386MWh battery energy storage system (BESS) for renewable energy producer Kallista Energy in northern France.
Construction of the two-hour system began in early July at Neuilly-en-Thelle in the Hauts-de-France region. Commercial operation is expected before spring 2028, according to the companies’ announcement.
Envision said it would supply the BESS and provide maintenance throughout its planned 25-year operating life. It will also be responsible for recycling the batteries at the end of that period.
The system will use lithium iron phosphate cells supplied by Envision AESC. The companies said these would be manufactured at AESC’s 10GWh battery factory in Douai, also in Hauts-de-France, which began production in June 2025.
Once operational, the BESS is intended to participate in reserve markets operated by French transmission system operator RTE, providing frequency regulation and other grid-balancing services. Envision said its storage capacity was equivalent to the daily electricity consumption of 30,000 households, although it did not state the consumption assumptions used for the comparison.
Henry Peng, senior vice-president of Envision Energy and president of its European and Latin American regions, said: “Our second BESS project with Kallista Energy reflects the continued growth of a partnership built on shared ambitions for Europe’s energy transition. Beyond delivering safe, reliable and scalable storage technology, Envision provides comprehensive lifecycle support, helping customers maximise long-term asset value.
“This integrated approach further advances our Future Energy System, strengthening grid resilience, accelerating the integration of renewable energy and supporting sustainable industrial development across Europe.”
Kallista Energy and Envision’s Somme project on target
The project follows Envision and Kallista Energy’s 120MW/240MWh BESS under construction at Saleux in the Somme department. Work on that project began in 2025 and is scheduled to be completed by the end of 2026. It was Envision’s first independent battery storage contract in France, according to Kallista Energy.
Johann Tardy, CEO of Kallista Energy Group, said: “Battery energy storage is a key driver to achieve electrification of energy consumption and massive expansion of renewable energies, which aim at reaching a low-carbon economy.
“For the battery energy storage system in Neuilly-en-Thelle, we are leveraging the strong collaboration built with Envision Energy on our previous project in Saleux to deliver a new high-quality storage infrastructure to further support the energy transition.”
France had 1,071MW of battery storage connected at the end of 2024, an increase of 216MW during the year, according to RTE’s annual electricity review.
