Green technology company Envision Energy has expanded its partnership with European renewable energy developer Kallista Energy to deliver a 193 MW / 386 MWh battery energy storage system (BESS) in Neuilly-en-Thelle, located in the Hauts-de-France region. Construction on the facility began in early July 2026, with full commercial operation targeted before spring 2028.
The Neuilly-en-Thelle initiative follows the Saleux project, Envision Energy’s inaugural BESS development in France that broke ground in 2025. The new development serves as a scalable model for European energy storage deployment while supporting regional grid modernisation efforts.
Envision Energy will supply its battery technology and handle full lifecycle management for the facility, covering ongoing site maintenance through to end-of-life battery recycling after 25 years of planned operation. The installation will utilise lithium iron phosphate (LFP) cells manufactured by Envision AESC at its 10 GWh gigafactory in Hauts-de-France, which has been operational since June 2025. Integrating local cell manufacturing with system integration is designed to reinforce domestic industrial capacity and build energy resilience.
Once operational, the storage system will supply flexibility services to the national grid, including frequency regulation through transmission system operator RTE’s reserve markets. With a capacity sufficient to cover the daily electricity demand of approximately 30,000 households, the facility aims to strengthen grid stability, facilitate higher renewable energy penetration, and assist national electrification goals.
Henry Peng, Senior Vice President at Envision Energy and President for EU & LATAM Regions, noted that the second joint BESS project underscores a shared strategy for the European energy transition. He added that combining technology delivery with comprehensive lifecycle support helps optimise long-term asset value, bolster grid resilience, and support sustainable industrial growth across the continent.
Johann Tardy, Chief Executive Officer of Kallista Energy Group, stated that battery storage remains a primary enabler for electrification and clean energy expansion. He highlighted that the Neuilly-en-Thelle project builds directly on the collaborative framework established during the Saleux development to deliver reliable storage infrastructure for the transition to a low-carbon economy.
