Harmony starts building third 100MW/200MWh French BESS

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BESS developer-operator Harmony Energy has started construction on a 100MW/200MWh BESS in France, its third to reach that stage in the country.

The firm announced the start of construction on the Foriaux battery energy storage system (BESS) in Eure, Normandy, yesterday (31 March) on LinkedIn.

BESS projects in France are currently benefitting from high ancillary service prices with a few years left before a need to revert to day-ahead and arbitrage revenues, Harmony Energy CEO Peter Kavanagh told ESN Premium in an interview last year.

Clément Girard, managing director of Harmony Energy France, said that the Foriaux BESS’ development has paid close attention to landscape integration, biodiversity and established a community benefit fund.

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It is the third reported 100MW/200MWh project in France that Harmony has brought to the construction stage, after the Chevire and Oise projects. Both have been sold to Swiss-based power firm Alpiq, Chevire shortly after commissioning in summer last year, while Oise was sold in late 2024, scheduled for 2026 operation.

Harmony hasn’t revealed the BESS supplier for Foriaux, while for Chevire it was Tesla, and the firm used the EV and BESS giant for most of its projects in the UK. Those were mostly rolled into the Harmony Energy Income Trust (HEIT) fund, which was sold and de-listed to asset manager Foresight Group in 2024. Kavanagh discussed this process in the interview too.

Tesla is also providing the BESS for the largest project under construction in France, a 240MW/480MWh system from TagEnergy.

2 December 2026
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Battery Asset Management Summit Europe is the annual meeting for owners, operators, investors, and optimisation specialists working with operational BESS assets across the continent. The Summit focuses on how to maximise performance and revenue, manage degradation, integrate advanced optimisation software, navigate evolving market and regulatory frameworks, and plan for repowering or end-of-life strategies. With insights from Europe’s most active storage markets, it equips attendees with practical guidance to run resilient, profitable battery portfolios as the sector scales.
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