IN Brief:
- Hams Hall Phase One will provide 350MW / 1,243MWh of grid-scale storage capacity.
- EDF will optimise the battery under a 10-year floor agreement using its PowerShift platform.
- A second phase is planned to lift the full site to 400MW / 1,424MWh.
EDF and BW ESS have agreed a 10-year optimisation deal for the first phase of the Hams Hall Battery Energy Storage System in North Warwickshire, a 350MW / 1,243MWh grid-scale storage project now under construction near Birmingham.
The project will be optimised through EDF’s PowerShift platform, allowing the asset to provide flexibility services to the electricity system by balancing supply and demand, supporting stability, and helping accommodate higher volumes of renewable generation. EDF said Hams Hall will be the longest-duration battery it has contracted to date, with the batteries capable of delivering power for up to 3.5 hours.
Phase One is expected to reach commercial operation in the fourth quarter of 2026. A second phase is planned to add a further 50MW, taking the total site to 400MW / 1,424MWh. The project is connected near the Hams Hall 400kV National Grid substation, placing it close to major demand centres and established transmission infrastructure.
Hams Hall is co-owned by BW ESS and AIP Management, following AIP’s acquisition of a 49% stake in a wider UK battery storage portfolio in 2025. Once completed, the project will become BW ESS’s largest capacity project globally, exceeding the scale of its Bramley BESS, a 100MW / 331MWh project that was the UK’s largest battery storage asset at inauguration in February 2025.
The UK battery storage market is moving beyond the first phase of short-duration assets built primarily around fast-response ancillary services. Larger projects with longer operating windows are being developed to manage daily variations in wind and solar output, evening demand peaks, and wholesale market volatility. Hams Hall’s 3.5-hour duration places it within that shift towards assets designed for a wider range of system services.
Storage revenue now depends on the interaction between physical performance, market access, trading capability, and operational control. Assets may participate in wholesale arbitrage, balancing markets, ancillary services, and constraint management, with optimisation platforms increasingly shaping how that value is captured. The commercial structure of Hams Hall reflects that more complex operating environment.
Grid location is also becoming a stronger differentiator for battery projects. Storage connected near robust transmission nodes and large demand centres can provide flexibility where it is most likely to be needed, while reducing exposure to local network limitations. Connection queues, curtailment costs, and regional constraints are already influencing which projects advance from pipeline to construction.
The project adds further scale to the UK’s growing storage base at a time when flexibility requirements are rising. Electrification of transport, heat, industry, and data infrastructure will increase demand, while renewable generation will continue to make output more weather-dependent. Batteries will not solve every flexibility requirement, particularly over multi-day periods, but large, well-located assets will form a core part of the operational toolkit for managing a lower-carbon electricity system.
Hams Hall marks another step in the industrialisation of UK battery storage: larger capacity, longer duration, stronger grid positioning, and commercial arrangements built around active optimisation rather than passive asset ownership.
