France’s electricity system is entering a new phase, one built on flexibility, digitalization, and local energy intelligence. Groupe Maxaindeau is partnering with Decade Energy to deploy a 10 MW / 20 MWh battery energy storage system (BESS) - the largest single-site storage project Decade Energy has signed to date.

This installation marks a decisive step for both companies and for the French energy landscape. It shows that the future of grid stability and renewable integration will not depend on a handful of mega-projects, but on a network of distributed batteries working together to keep the system balanced, clean, and reliable.

Located on Groupe Maxaindeau’s site, the BESS will connect directly to the grid, delivering fast, local flexibility services to the national transmission operator, RTE. With 10 MW of instantaneous power and 20 MWh of capacity, the system can store renewable electricity when production is high and release it within seconds when demand peaks. This helps smooth local variations, relieve congestion, and support frequency regulation across the regional network.

“Front-of-the-meter projects like this are the missing link between renewable generation and grid reliability. Each distributed site adds fast, local flexibility to the French system that stabilizes supply, reduces congestion, and helps RTE operate a cleaner grid.”

– Aymeric Leenhardt, VP of Business Development at Decade Energy

A 10 MW battery may seem modest compared to utility-scale mega-sites, but its impact is immediate. In one hour of discharge, it can deliver about 10 MWh of energy, which is enough to power roughly 20,000 French households for that period. More importantly, it operates where the grid needs the most support - close to industrial loads and renewable generation - providing fast, localized services that large, centralized plants cannot deliver as quickly or efficiently.

Across France, the growth of front-of-the-meter storage marks a structural shift. Instead of building flexibility in a few massive locations, grid operators are increasingly relying on distributed, digitally coordinated assets. These smaller batteries respond in milliseconds, adapt to regional grid needs, and together form a vast, invisible infrastructure that underpins the energy transition.

For Decade Energy, the Groupe Maxaindeau project illustrates how France’s flexibility market is maturing. This is continued proof that energy storage is a core component of the national system. Each new project expands the country’s capacity to manage renewable variability and maintain reliability without fossil backup.