Certain Energy raises £10M Series A for long-duration battery storage

British long-duration energy storage company Certain Energy has raised £10 million in Series A funding to commercialise its manganese flow battery technology and prepare it for grid-scale deployment. 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 (C3H).

Founded in 2017 as a spin-off from Imperial College London and previously known as RFC Power, Certain Energy is developing long-duration energy storage (LDES) systems designed to store renewable electricity and release it when production from sources such as wind and solar is low. The technology is intended to help stabilise electricity grids, reduce renewable energy curtailment and limit reliance on gas-fired peaker plants.

As renewable generation increases, electricity grids face periods when production exceeds demand as well as periods when renewable output is insufficient. Certain Energy is targeting this imbalance with flow batteries based on manganese, an abundant element that the company says can provide a lower-cost alternative to materials used in other long-duration storage technologies.

Unlike conventional batteries, flow batteries store energy in liquid electrolytes held in external tanks. Certain Energy's system can increase its discharge duration by expanding the size of these tanks, allowing energy to be stored and discharged over periods ranging from hours to days.

According to the company, its technology achieves round-trip efficiency of more than 75 per cent and is designed to compete with lithium-ion batteries for key grid services while providing the longer-duration storage and reserve capacity required by grids with increasing levels of renewable generation.

Certain Energy's patented electrolyte is designed for a 20-year operating life with limited capacity degradation. The company also says its design and choice of materials could reduce marginal storage costs to around one-tenth of those associated with comparable vanadium flow batteries.

The Series A funding will support the development of a grid-connected MWh-class system in India, the expansion of Certain Energy's UK research facility and the development of a supply chain to support commercial deployments. The company will also continue preparing its technology for volume production and broader commercialisation.