- Certain Energy, previously known as RFC Power, has raised £10 million in its Series A funding round, with the British Business Bank as the lead investor.
- Last year, the United Kingdom paid around £1.5 billion to renewable energy producers to reduce the amount they produced. The sum could reach £8 billion by 2030.
- Centrica, Ceres Power, and Catalytic Capital (part of the Temasek Trust) are also taking part in this round. The funds will be used to finance a project connected to the grid in India and to support research and development in the UK.
In 2025, Britain paid wind and solar farms £1.5 million a day to reduce their output, and left unaddressed, the grid operator expects that to climb towards £8 billion a year by 2030. To tackle this, Certain Energy, a spin-off from Imperial College London, has raised £10 million in its Series A funding round.
The British Business Bank led the group of investors with an investment of £3.5 million, with Centrica, Ceres Power Holdings, and Catalytic Capital for Climate and Health from the Temasek Trust also taking part.
Mark Selby, the executive chair, stated, “The renewable power market is held back by its vulnerability to external factors. The answer is long-duration energy storage, and Certain Energy has the technology and now the funding to deliver highly efficient, affordable batteries, based on abundant materials, to make this a reality.”
The global long-duration energy storage market was worth $3.6 billion in 2025 and is expected to rise to $9.5 billion by 2035, representing a 10.5% compound annual growth rate. Currently, most of the growth is being driven by US-backed iron-air and mechanical storage companies, which are receiving much larger amounts of funding.
From Imperial College lab to independent company
Certain Energy was set up in 2017 as a spin-off from Imperial College London by the professors Anthony Kucernak and Nigel Brandon. It took eight years to develop its technology. In September 2025, it became a fully owned subsidiary of Ceres Power.
Certain Energy is now independent once again, even though Ceres still holds about 37% and will receive a share of any future product revenue in exchange for continued engineering support.
Stuart Paynter, Ceres’ finance chief, said, “Certain Energy has a combination that is rare in this sector: a low-cost, abundant chemistry and a credible, capital-efficient route to manufacturing. We’re glad to back a fellow UK innovator with global ambitions.”
Instead of using lithium or vanadium, the company uses manganese, the twelfth most common element in the Earth’s crust, as its battery electrolyte. To increase storage time, they enlarge the electrolyte tanks rather than add more cells.
As a result, grid operators can extend storage by increasing tank size rather than by installing new systems. The technology has a round-trip efficiency of more than 75%, and the company states that the electrolyte can last for 20 years with only slight degradation.
How manganese compares to other battery technologies
In the UK, Ore Energy has raised $43 million for its iron-air storage project, claiming that this is ten times cheaper than lithium-ion. In the United States, Form Energy has raised more than $1.2 billion for similar technology and already has commercial contracts in place.
Vanadium remains the main flow-battery technology, but it is costly, and its supply is limited to specific regions. EnerVenue has raised $300 million for an alternative based on metal-hydrogen.
Certain Energy states that manganese is cheaper than all of these other options and that its storage costs are about one-tenth of those of vanadium flow systems. However, unlike Form Energy, it has not yet demonstrated that its technology works on a grid scale.
Michael Shanks, the minister of state at the Department for Energy Security and Net Zero, described the initiative as grid infrastructure rather than a typical startup investment.
“Homegrown clean energy is our route to more affordable bills and energy security, and storing it for when we need it most is critical. By investing £3.5 million in Certain Energy, the British Business Bank is backing British innovation and helping develop the long-duration energy storage we need to store clean power for days, not hours, and deliver a more secure energy system.”
Unlike other recent companies such as Suena Energy and The Storage, Certain Energy is distinguished by its government support, private investment from Centrica, and impact capital from Temasek’s C3H. The other companies were funded solely by private and corporate venture capital.
Tim von Werne, the company’s chief executive, added, “Long-duration storage is the missing piece of the clean energy system, and manganese flow is the technology that should win. With the British Business Bank behind us, we have the capital and the mandate to build a global champion here, turning world-class UK science into the industry the energy transition needs.”
The £10 million, which marks Certain Energy’s first source of funding outside Ceres, will be used to fund a grid-connected MWh-class demonstration project in India, support the expansion of the UK research facility, and assist in developing the supply chain required for future growth.
