Seven first-of-a-kind energy storage projects have completed government-backed trials aimed at keeping renewable power available during long periods of low wind and reducing reliance on gas.
The Department for Energy Security and Net Zero has published the final reports from the £70 million Longer Duration Energy Storage Demonstration Programme, which ran from 2021 to 2026.
The programme supported technologies capable of storing energy over days, weeks or months rather than the shorter periods typically served by lithium-ion batteries.
Projects covered thermal storage, electricity storage and power-to-X systems, with seven schemes progressing from feasibility studies to full prototype development and demonstration.
Sunamp received £9.2 million for its EXTEND project, which combined thermal batteries and smart controls with household heating systems. The technology was trialled across 100 UK homes to assess whether fleets of thermal stores could help networks manage periods of low renewable generation.
The University of Sheffield’s £2.6 million ADSorB project developed modular heat storage and intelligent controls for homes, with prototype systems installed at the University of Nottingham’s Creative Energy Homes campus.
EDF-led HyDUS received £7.7 million to demonstrate hydrogen storage using depleted uranium technology adapted from the fusion industry. The system is designed to hold large quantities of hydrogen safely for long periods before releasing it when energy is needed.
Electrical storage projects included StorTera’s £5 million single-liquid flow battery, which used recyclable materials and wood industry by-products. Eight modules were combined to create a 200kW, 1.6MWh demonstrator near Edinburgh.
RheEnergise received £8.2 million to test its high-density hydro system, which uses a fluid denser than water to generate electricity from smaller hills than conventional pumped storage. Its prototype was designed to provide 250kW of power with four hours of storage.
SynchroStor’s £9.4 million pumped thermal system converted electricity into heat before turning it back into power, targeting a grid-connected megawatt-scale demonstrator with 10 hours of storage.
Cheesecake Energy received £9.4 million for FlexiTanker, which combines compressed air and thermal storage. Pilot units were linked to a Colchester microgrid alongside up to 8MW of solar generation and a heat network.
The reports do not mean every technology is ready for large-scale commercial deployment but they provide evidence on performance, engineering challenges and potential costs.
Long-duration storage could allow excess renewable electricity to be saved rather than curtailed, then released during extended periods of low wind when the system would otherwise rely more heavily on gas.
Copyright © 2026 Energy Live News LtdELN