UK-based Harmony Energy has announced that it will commence construction on the Cheviré battery project, France's largest battery energy storage system (BESS).

The BESS facility will be equipped with Tesla Megapack technology.

The Cheviré battery project will be built at Nantes Saint-Nazaire harbour on the site of the former Cheviré power station.

Harmony Energy France chief operating officer Clément Girard stated: “It’s an exciting location, given the historical importance of the fossil-fuel coal power station, but looking ahead, the delivery of the Cheviré BESS will transform the site into exactly the opposite, facilitating the green electrification of the French energy system, whilst offsetting several hundred thousand tons of CO₂.”

The BESS system will power 170,000 homes for two hours - supplying a population larger than that of the city of Nantes.

Harmony Energy France CEO Andy Symonds stated: “Developing and operating vital battery energy storage facilities across France, will lead to enhanced energy security, more affordable energy bills, and the decarbonisation of the grid. We are excited to commence building works on our first project.”

It will be the country’s first large-scale two-hour battery.

In March 2024, Fotowatio Renewable Ventures (FRV) and Harmony Energy activated the 99MW/198-megawatt hours Clay Tye BESS in Essex, UK.

One of the largest such operational projects in Europe, the system can supply power 300,000 homes for up to two hours.

The Clay Tye site features 52 Tesla Megapack lithium-ion batteries, along with Tesla's Autobidder AI software.

This technology allows for energy capacity sharing and optimises project management.