Harmony Energy, a leading European developer of battery energy storage systems (BESS), has successfully energised the Cheviré battery project – now the largest of its kind in France. Located in the port of Nantes Saint-Nazaire Harbour, the 100 MW / 200 MWh facility marks a major step forward for France’s renewable energy ambitions, becoming the country’s first large-scale, two-hour duration battery storage system.
The project is built on the site of the former Cheviré fossil fuel power plant, which consumed coal, gas and oil from 1954 to 1986. Situated adjacent to the grid operator’s substation, the site’s transformation into a state-of-the-art renewable energy asset symbolises a powerful shift from fossil fuels to clean energy solutions.
Using Tesla’s Megapack and Autobidder technologies, the Cheviré energy storage system will provide essential balancing services to the national grid, helping to replace fossil fuel peaking plants with renewables. With the ability to power approximately 170,000 homes for two hours, 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, and accelerating France’s energy transition.
Andy Symonds, CEO of Harmony Energy France, said: 'The Cheviré battery project is a landmark achievement for the wider energy transition in France. It shows how disused industrial sites can be repurposed to enable a more sustainable electrification of our power systems. This project strengthens energy security, supports affordability, and helps pave the way for a cleaner, energy system which is less reliant on burning fossil fuels.
'We began construction on site in summer 2024 and have just achieved energisation, one year later, showcasing how expertise, skill and productive collaboration between teams working on a shared goal can accelerate the transition to net zero.'
Beyond energy, Harmony Energy is committed to delivering projects that protect nature, support local communities, and lead the way in innovation. The Cheviré project includes biodiversity initiatives, provides commitments to supporting local social and environmental causes through a community benefit fund, and is built using industry-leading technology, ensuring the positive impact extends far beyond the electricity grid.
Source: Harmony Energy
