Projects
Cheviré BESS

Cheviré BESS

Cheviré BESS, located in the Port of Nantes Saint-Nazaire, is set to become France’s largest battery energy storage system once energised in late 2025. With a capacity of 100MW/200MWh, the two-hour duration system is being built on the former site of the Cheviré oil, coal, and gas power station, making full use of the site's existing grid infrastructure. Once operational, the project will have the capacity to supply electricity to approximately 170,000 homes.

This landmark project marks the first deployment of Tesla Megapacks and Tesla's Autobidder energy management platform in France. Although battery storage technology has been in limited use domestically for around a decade, Cheviré BESS will be the first large-scale installation of its kind in the country. It will play a vital role in France’s energy transition by providing essential flexibility to the grid, enabling the secure integration of renewable energy, supporting supply stability, and helping to control costs for consumers and grid operators alike.

Sector	Battery Storage
Developer	Harmony Energy
Project	Cheviré BESS
Location	Nantes, France
Scope of Work	110MVA 63/33kV Wilson Power Transformer Twenty-six 4200kVA 33kV/480–480V Wilson T2 Ecotrans® Large Distribution Transformers 150kVA Wilson Auxiliary Transformer

To support this landmark development, we continued our long-standing partnership with Harmony Energy by supplying a 110MVA 63/33kV Wilson Power Transformer, twenty-six 4200kVA 33kV/480–480V Wilson T2 Ecotrans® Large Distribution Transformers, and one 150kVA Wilson Auxiliary Transformer. The Wilson Large Distribution Transformers were custom-engineered for seamless compatibility with Tesla Megapack systems, ensuring optimised energy performance to support the high cycling demands typical of grid-scale battery systems.

200 MWh

storage capacity

MV Transformers

170000

homes powered

for two hours

The Cheviré BESS project is the latest milestone in our collaboration with Harmony Energy, following our involvement in the UK’s four largest BESS sites. It reflects our commitment to supporting energy storage infrastructure at scale across Europe. Cheviré BESS is a flagship project for France’s clean energy transition, offering vital grid stability and flexibility as the country accelerates its move away from fossil fuels. Our contribution to Cheviré builds on years of expertise in the energy storage sector and reinforces the importance of high-performance, reliable transformer technology in delivering the net zero ambitions of tomorrow.