RFC Power Rebrands as Certain Energy, Raises £10M for Manganese Flow Batteries

Certain Energy, formerly known as RFC Power, has raised £10 million in Series A funding for its manganese flow battery technology, alongside rebranding from its original name. The round was led by the British Business Bank, with participation from Centrica, Ceres Power Holdings and Temasek Trust's Catalytic Capital for Climate and Health. The funding will support a grid-connected megawatt-hour-class system in India, expansion of the company's UK research facility, and development of the supply chain needed for replicable project deployment.

 

Why Scaling Tank Size Changes the Underlying Cost Curve for Long-Duration Storage

 

Certain Energy's flow battery design allows discharge duration to be extended simply by increasing the size of its electrolyte storage tanks, enabling storage ranging from hours to multiple days. That architecture differs fundamentally from conventional battery chemistries like lithium-ion, where increasing storage capacity generally requires adding more battery cells, each carrying the full cost of its active materials and manufacturing regardless of whether the added capacity is used for power output or storage duration.

By decoupling duration from the core battery cell cost, flow battery designs like Certain Energy's can, in principle, add extended discharge duration considerably more cheaply, since electrolyte storage tanks are a comparatively low-cost way to add capacity relative to manufacturing additional battery cells. The company states its patented electrolyte is designed for a 20-year operating life with minimal capacity degradation, and that its materials and design have the potential to reduce marginal storage costs to around one-tenth of comparable vanadium flow batteries and considerably below lithium-ion systems.

 

Why the £1.5 Billion Curtailment Figure Frames the Commercial Case

 

Executive Chair Mark Selby tied the investment directly to a specific and growing cost problem facing the UK grid: "Last year, the UK Government spent around £1.5 billion asking renewable energy providers to shut off their operations during peak production, and left unaddressed, the grid operator expects that to climb towards £8 billion a year by 2030." That curtailment payment, compensating renewable generators for reducing output when the grid cannot absorb their full generation, represents a direct and escalating cost stemming from insufficient grid flexibility and storage capacity to make full use of renewable generation when it's actually available.

That figure gives concrete financial weight to the argument that long-duration storage isn't simply an environmental nice-to-have but addresses a cost the UK energy system is already incurring and projected to see grow substantially, framing Certain Energy's technology as targeting an existing and quantified market inefficiency rather than a speculative future problem.

 

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Why Manganese's Abundance Matters as a Distinct Advantage

 

Certain Energy's technology uses manganese, described as the twelfth most abundant element in the Earth's crust, as its core battery chemistry, distinguishing it from vanadium flow batteries, a more established long-duration storage technology that relies on a considerably scarcer and more expensive metal. C3H's Ryan Tan specifically noted the technology "replaces traditional battery elements with earth-abundant materials such as manganese to deliver cost-effective and scalable long-duration storage performance with less environmental impact."

That distinction matters for long-term scalability: a storage technology dependent on a comparatively scarce material like vanadium faces inherent supply and cost constraints as deployment scales globally, whereas a technology built on an abundant material like manganese avoids that structural bottleneck, a genuine advantage if the underlying manganese-based chemistry can deliver comparable performance to vanadium flow systems, which the company claims through its stated round-trip efficiency above 75 percent, positioning it to compete economically with lithium-ion batteries on key grid services.

 

What the Investor Syndicate Signals About Cross-Sector Validation

 

The funding round drew participation from Centrica, a major UK energy company, and Ceres Power, a fuel cell and electrolyser technology company, alongside the British Business Bank and Temasek Trust's climate-focused C3H vehicle. Centrica's Rob Booker said "long duration storage is critical to managing the energy system of the future, and Certain Energy's technology is exactly the kind of innovation needed to reduce costs and improve efficiency, while supporting a more renewables-led, intermittent power mix." Ceres CFO Stuart Paynter described the company as having "a combination that is rare in this sector: a low-cost, abundant chemistry and a credible, capital-efficient route to manufacturing."

That combination of a state-backed development bank, an established energy utility, and a specialist clean energy technology company all participating in the same round gives the investment a broader base of technical and commercial validation than a purely financial venture round would carry alone, spanning both public policy-driven capital and strategic industry expertise.

 

What Comes Next

 

British Business Bank managing director Charlotte Lawrence said the investment would help the company "commercialise and take the next steps towards deployment," while UK Minister of State Michael Shanks framed the £3.5 million portion of British Business Bank funding as helping "develop the long-duration energy storage we need to store clean power for days, not hours." Chief executive Tim von Werne described long-duration storage as "the missing piece of the clean energy system," stating the company now has "the capital and the mandate to build a global champion here, turning world-class UK science into the industry the energy transition needs."

Whether Certain Energy's manganese flow battery technology performs at the scale and cost the company projects once its planned India grid-connected system moves from development into operation, and whether the technology's stated one-tenth cost advantage over vanadium flow batteries holds up at genuine commercial manufacturing volume, will determine how significantly this funding round advances the company's ambition to address the escalating curtailment costs its executive chair specifically cited as the market opportunity driving this investment.

 

Source: Certain Energy