Certain Energy Raises £10M—Its First Grid-Scale Test Will Be in India
On August 26, 2026, RFC Power completed a £10 million Series A and rebrand as Certain Energy. The British Business Bank led the round, with Centrica, Ceres Power and Temasek Trust’s Catalytic Capital for Climate and Health participating; the proceeds are earmarked for an Indian grid-connected MWh-class system, expanded UK research facilities and a commercial supply chain.
The Indian project is a financed development target, not an operating battery asset. An independent account of the deployment plan identifies it as the company’s first grid-connected installation at megawatt-hour scale and records management’s projection that marginal storage costs could fall to around one-tenth of current alternatives; neither the installation nor the projected economics has yet been validated through a commercial fleet.
The round changes Ceres from sole owner to minority shareholder
The financing is also a corporate spinout. RFC Power had become a wholly owned Ceres subsidiary after Ceres acquired its remaining shares and intellectual property for a nominal amount in September 2025.
Ceres’s regulatory ownership statement sets out a £1 million cash contribution, a further £1.5 million equity award in exchange for engineering services, an approximately £12 million post-money valuation and a retained Ceres stake of about 37%. Ceres will also receive a share of future product revenue, and its chief financial officer, Stuart Paynter, is joining the battery company’s board.
Ceres therefore remains a substantial shareholder and engineering partner, but it no longer owns the business outright. The Series A brings strategic and institutional investors onto the register while giving Certain Energy a separately funded identity under its new name.
The disclosed terms do not allocate the entire round among the participating investors. British Business Bank’s lead role and Ceres’s consideration are known, but the individual contributions from Centrica and Temasek Trust’s fund have not been itemised publicly. No basis exists for assuming that the undisclosed balance was divided evenly.
India is the next engineering milestone, not a completed test
The proposed Indian installation matters because it is intended to move the technology from research and component development into an integrated grid environment. At that scale, the electrochemical stack must operate with electrolyte tanks, pumps, controls, power-conversion equipment and the host site’s electrical infrastructure.
An energy rating at megawatt-hour scale does not by itself disclose the system’s power output or discharge duration. Those depend on the final configuration, while the commercial value will also depend on the operating schedule, grid service, availability and usable capacity delivered at the site.
Important project details remain absent. Certain Energy has not publicly named the customer, host utility, site, power rating, construction contractor or commissioning timetable. There is also no indication that construction has started.
The word “test” in the headline therefore describes the planned project’s role as a first grid-scale validation step. It does not mean that a field trial has been completed or that operating results are available.
The manganese flow battery separates power from duration
Certain Energy is developing a hydrogen-manganese flow battery for long-duration electricity storage. Flow batteries hold liquid electrolytes in external tanks and circulate them through an electrochemical stack. The stack largely determines power, while larger tanks and more electrolyte can extend storage duration without requiring a directly proportional increase in stack capacity.
This separation underpins the economic case for long discharge periods. Manganese is intended to provide a less costly material basis than vanadium, the chemistry used in established commercial flow-battery systems, but raw electrolyte is only one part of a project’s cost.
Tanks, pumps, membranes, stacks, power electronics, civil works, grid interconnection and maintenance all contribute to installed economics. A low marginal cost for adding electrolyte capacity therefore cannot establish the cost of a complete grid-connected system.
Other headline performance assertions concern round-trip efficiency, operating life and limited degradation. These remain company claims rather than commercial proof: the disclosed material does not include an independent test report covering a complete duty cycle, a field-availability record or a cost comparison derived from an operating MWh-class installation.
The Series A finances the route to proof
The completed round demonstrates investor support for a defined commercialisation programme. Certain Energy now has capital allocated to UK research capacity, supply-chain development and the integration of its first disclosed grid-connected system in India.
It has not yet demonstrated the performance of that programme at grid scale. Laboratory measurements and component tests cannot establish the efficiency, availability, degradation rate, maintenance burden or installed cost of a full system operating under real dispatch requirements.
The next material evidence will be a named Indian project partner, a site and construction schedule, followed by commissioning and operating data. Until then, the financing and ownership change are completed events, while the deployment and its claimed economics remain milestones to be tested.
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