September 8, 2025: Harmony Energy has launched what it says is France’s first large-scale two-hour duration BESS.

Harmony said on August 14 the 100MW/200MWh Cheviré facility, at the port of Nantes Saint-Nazaire Harbour, can power about 170,000 homes for two hours, equivalent to more than the entire population of Nantes.

The site will play a pivotal role in boosting grid resilience, cutting carbon emissions, reducing energy costs and volatility, Harmony said.

The BESS, built on the site of the former Cheviré fossil fuel power plant, which consumed coal, gas and oil from 1954 to 1986, uses battery tech supplied by Tesla’s Megapack and Autobidder.

Andy Symonds, CEO of Harmony Energy France, said Cheviré showed how disused industrial sites could be repurposed. “We began construction on site in summer 2024 and have just achieved energisation, one year later.”