On 20 August 2026 the UK government launched the Ultra-Long Duration Energy Storage Challenge, offering £28 million through UK Research and Innovation for technology intended to store clean electricity for 100 hours or more — described as enough to power homes and businesses for at least four days. The Department for Business, Innovation, Science and Trade and the Department for Energy Security and Net Zero said bidders could seek grants in two areas: new battery technologies, which the release said are not yet commercialised at scale, and systems that store hydrogen underground and release it when needed. The launch was reported as following another heatwave and as part of wider clean energy ambitions.

Ministers Chris McDonald and Michael Shanks framed the funding as a route to greater energy security and lower long-term bills by reducing reliance on gas-fired generation. UKRI's Jenny Hill said the challenge could help place the UK at the forefront of the global storage market. Hydrogen UK chief executive Clare Jackson said hydrogen has a fundamental role in storing renewable energy over long periods. UKRI also launched a competition of up to £3 million for studies into electrochemical ultra-long duration storage. The release said underground hydrogen storage could reduce total energy system costs by between £14 billion and £50 billion between 2035 and 2050.

The announcement completed the roll-out of £102 million in Clean Energy challenges up to 2030, including £74 million for the Consumer-led Flexibility Challenge, under the R&D Missions Accelerator Programme, which the release said is investing at least £500 million by 2030. It also noted that Ofgem was consulting on plans to support 16 long duration electricity storage projects.