EDF has partnered with global energy storage developer, owner and operator BW ESS to optimise the first phase of the Hams Hall Battery Energy Storage System (BESS) in North Warwickshire. The grid-scale project, rated at 350MW/1,243 MWh, is the longest-duration battery EDF has contracted so far and is intended to strengthen flexibility and resilience in Britain's electricity system as renewable output grows.

Under a 10-year floor agreement, EDF will optimise the asset via its PowerShift platform, enabling the battery to balance supply and demand, support grid stability and help integrate higher volumes of wind and solar generation.

Phase one will provide 350MW of capacity, with a subsequent phase adding 50MW to bring the total to 400MW/1,424 MWh. The scheme is under construction on the north-eastern edge of Birmingham and is due to enter commercial operation in Q4 2026.

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Once operational, the system will be capable of meeting the electricity needs of about 1.3 million homes for up to 3.5 hours. It is connected to the nearby Hams Hall 400kV National Grid substation and benefits from proximity to major demand centres, reducing congestion risk and improving access to arbitrage and balancing services.

Hams Hall is a cornerstone of BW ESS's UK portfolio and is co-owned alongside energy and decarbonisation investor AIP Management. On completion, it will be BW ESS's largest-capacity project worldwide, at roughly four times the size of Bramley BESS (100MW/331 MWh), which was the UK's largest when inaugurated in February 2025.

Stuart Fenner, Wholesale Market Services Director at EDF, said: "Hams Hall will be the longest duration battery EDF has contracted to date. By optimising it through our PowerShift platform, we can unlock the flexibility needed to support more renewable power and help deliver EDF's purpose of electrifying Britain."

Kilian Leykam, Executive Director, Revenue, BW ESS, added: "We're very pleased to welcome EDF as our optimisation partner on the Hams Hall project. This collaboration enables a revenue structure designed to maximize the commercial potential of this strategically important UK asset. By combining BW ESS's experience in developing and operating utility-scale battery storage projects with EDF's optimisation expertise, we will ensure that Hams Hall delivers exceptional value while fulfilling its role as a key flexibility asset in the UK electricity system."

The project contributes to EDF's expanding battery storage portfolio, reflecting the increasing role of grid-scale storage in balancing the UK's electricity system as renewable generation accelerates.