Currently under construction, the Hams Hall BESS project is expected to reach commercial operations in the fourth quarter of 2026.
April 28, 2026
French utility EDF has partnered with energy storage developer BW ESS on the first phase of the Hams Hall battery energy storage system (BESS) in North Warwickshire.
Through its PowerShift platform, EDF will optimise the 350MW/1,243MWh BESS plant, under a 10-year floor agreement. This will enable the battery to deliver flexibility to the grid by balancing supply and demand, supporting grid stability and helping the integration of new renewable energy generation.
Currently under construction, the project is expected to reach commercial operations in the fourth quarter of 2026, with a second phase expected to add 50MW/210MWh capacity at a later date. Hams Hall is a key project from BW ESS’s UK portfolio and is co-owned with energy investor AIP Management, which acquired a 49% stake in the project and other UK assets in September 2025.
Once operational, the project will be BW ESS’s largest capacity project globally, increasing by four-fold the Bramley BESS project (100MW/331MWh), which was at the time the UK’s largest operational BESS plant, according to the company.
Related:SSE Renewables commissions 150MW/300MWh Ferrybridge BESS in West Yorkshire
Stuart Fenner, Wholesale Market Services Director at EDF, said: “Hams Hall will be the longest duration battery EDF has contracted to date (3.5-hours). 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.”
The site benefits from proximity to major electricity load centres and is connected to the nearby Hams Hill 400kV National Grid substation. This will allow the project to reduce congestion risks while maximising access to arbitrage and balancing services.
This latest optimisation partnership further increases EDF’s growing battery storage portfolio in the country, and comes one month after the power firm secured a similar partnership with independent power producer Matrix Renewables. EDF will provide route-to-market (RTM) services and optimisation for the 500MW/1,000MWh Eccles BESS project in Scotland once it begins commercial operations in summer 2027. 
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