UK independent power producer (IPP) Voltwise Power has raised £153.9 million (US$211.4 million) in funding to support its acquisition of a 460MW battery energy storage system (BESS), which was completed last year.
The deal, which closed in June 2025, saw the IPP acquire a BESS portfolio from UK energy infrastructure company Smart Metering Systems (SMS), which at the time was spread across seven 320 MW/250 MWh operating assets and a further four 140 MW/280 MWh assets under development.
However, the deal also included the acquisition of SMS’s entire battery business, and Voltwise said the portfolio includes “a number of development assets” in addition to the projects mentioned, although he did not provide further details on this portfolio.
The deal was supported by Santander CIB, which acted as M&A advisor, while NatWest, Kommunalkredit and Siemens Financial Services were part of the syndication process. Voltwise is owned by investment firm Sandbrook Capital and said the completion of the deal, and the huge number of companies involved in signing it, ‘demonstrates the confidence of lenders in the UK BESS sector’.
This confidence is in stark contrast to uncertainty expressed last year that Ofgem’s new cap-and-floor scheme for long-term energy storage (LDES) introduces bias against BESS projects. Voltwise CEO Russell Alton was one of seven signatories an open letter arguing that the support scheme amounts to “a government trying to pick winners”as opposed to encouraging investment in technologies that have the greatest financial potential.
Opposition to the plan also came in the form of a legal challenge that Zenobē launched earlier this month. However, figures show this more than two-thirds of successful projects in the first round of the Ofgem support program used lithium-ion BESS technologysuggesting there may be a place for BESS in the UK storage market in the future.
Solar energy portal publisher Solar Media will host the 11th edition of the Energy Storage Summit next month, taking place on February 24 and 25 in London. Topics of discussion include routes to market for BESS projects, the role of grid connection reform and how battery companies can address global supply chain risks. Read more about the event and reserve tickets at the website.
