AIP Management, an investor in energy and decarbonization infrastructure, has agreed to acquire a 49% equity stake in a U.K.-based battery energy storage system portfolio with a combined capacity of 700 MW and 3.5-hour duration from BW ESS, an energy storage project developer, owner, and operator.
The portfolio comprises three projects, including the operational 100 MW/331 MWh Bramley project, the 400 MW/1,422 MWh Hams Hall project, and the 200 MW/712 MWh Berkswell project, all of which are currently under construction.
Located in the Midlands and Southeast of England, the portfolio benefits from proximity to major electricity load centres and National Grid substations. Once operational, the projects are expected to support the electricity needs of millions of U.K. households for 3.5 hours.
This acquisition marks AIP’s first dedicated investment in standalone battery storage. Once completed, the projects will be held in a newly formed AssetCo, with BW ESS retaining a 51% majority stake. The transaction is subject to customary and regulatory approvals.
BW ESS will manage the construction and operations of the portfolio. “This investment reflects our conviction in the U.K. energy storage market and builds on the knowledge we have developed through our existing investments in co-located BESS,” said Greg Falzon, Partner and Co-Head of Investments at AIP. “We are very pleased to form this partnership with BW ESS, which brings highly complementary industrial expertise and operational capabilities to our investment approach. Together we will deliver long-term value while enabling the deployment of critical flexibility in the U.K. power system.”
According to Mercom’s 1H and Q2 2025 Funding and M&A Report for Energy Storage report, announced Energy Storage project financing increased 168% year-over-year in 2025.
In September, GridStor, a developer and operator of utility-scale battery energy storage projects, announced the acquisition of the 100 MW/400 MWh White Tank battery storage project in Arizona from Strata Clean Energy, a vertically integrated solar and storage project developer.