- The former RFC Power has raised £10m from investors including British Business Bank, Centrica Energy, Ceres Power and Temasek Trust’s C3H.
- The Imperial College spinout will use the funding to build its first grid-connected megawatt hour scale system in India and expand UK research and supply chain capacity.
- Manganese could lower flow battery costs, but the financing remains an early step towards proving commercial performance at utility scale.
British long-duration electricity storage (LDES) developer Certain Energy has raised £10m to commercialise its manganese flow battery, as the UK seeks a wider range of technologies capable of balancing a renewables-heavy power system.
The Series A round included £3.5m from British Patient Capital, part of the government-owned British Business Bank. Centrica Energy, Ceres Power and Temasek Trust’s Catalytic Capital for Climate and Health also participated.
Certain Energy was founded in 2017 as RFC Power, an Imperial College London spinout. It is developing a flow battery intended to store electricity for periods ranging from hours to days and potentially weeks.
The company plans to use the funding to construct its first grid-connected, megawatt-hour scale installation in India, expand its UK research facility and develop a supply chain capable of delivering repeatable commercial projects, according to the British Business Bank.
“Homegrown clean energy is our route to more affordable bills and energy security, and storing it for when we need it most is critical,” said energy minister Michael Shanks.
Lower-cost flow chemistry
Like other flow batteries, Certain Energy’s system stores energy in liquid electrolytes held in external tanks. Power capacity is determined largely by the cell stack, while energy duration can be increased by installing larger tanks and more electrolyte.
This separation can make flow batteries attractive for longer durations, where simply adding lithium-ion battery packs may become comparatively expensive. Flow batteries can also be cycled repeatedly with less degradation than many conventional batteries, although they usually have lower energy density and round-trip efficiency.
Certain Energy is seeking to replace vanadium, the material used in the best-established flow battery chemistry, with manganese. Manganese is considerably more abundant and potentially cheaper, reducing exposure to the concentrated supply chains and volatile prices associated with vanadium.
The company claims its technology can reduce the marginal cost of LDES to around one tenth of current alternatives. That remains a company projection rather than performance demonstrated across a fleet of commercial installations. The India project will therefore be important as both an engineering trial and a reference asset for prospective customers.
The investor group offers more than capital. Centrica Energy brings experience in electricity trading and optimising flexible assets, while Ceres contributes UK electrochemical technology and commercialisation expertise. Public participation through British Patient Capital reflects the government’s desire to retain more value from university-developed intellectual property.
Market conditions are improving. In June, Ofgem provisionally selected 16 projects for Britain’s first LDES cap-and-floor scheme. The portfolio covers pumped hydro, compressed air, lithium-ion and vanadium flow batteries, with long duration defined as at least eight hours.
Manganese flow technology was not among the selected categories, highlighting both Certain Energy’s opportunity and its maturity gap. If the company can establish reliability, efficiency and competitive installed costs, it could offer a more geographically flexible alternative to pumped hydro and compressed-air storage.
