Certain Energy Raises £10M Series A for Manganese Flow Batteries

The firm's flow batteries store energy in liquid electrolytes kept in external tanks. Because discharge duration can be extended by enlarging those tanks, the system can store and release energy over periods ranging from hours to days. Certain Energy uses manganese, an abundant element it says offers a lower-cost alternative to materials used in other storage technologies.

Mark Selby, Executive Chair of Certain Energy, told EU-Startups that the renewable power market is held back by its vulnerability to external factors. He said the UK Government spent around £1.5 billion last year paying renewable providers to curtail output during peak production, and the grid operator expects that figure to rise toward £8 billion a year by 2030 if left unaddressed.

EU-Startups reported that the round arrives amid significant investment in European energy-storage and grid-flexibility companies in 2026, noting at least €167 million across seven comparable or adjacent rounds. These include Amsterdam-based Ore Energy's €37.3 million Series A for iron-air batteries, Oslo-based Photoncycle's €15 million Series A for seasonal storage, and a round for Munich-based encosa.

Recent seed and pre-seed rounds back Sweden's Pixel Systems, France's Bleu Robotics and Colorado's Rendezvous Robotics, spanning digital verification, humanoid robots and modular spacecraft.