UK completes trials of seven long-duration energy storage projects
The UK government published final results from seven long-duration energy storage demonstration projects, funded with over 51 million pounds since 2021.
Photo by Petr Ganaj on Pexels
The UK Department for Energy Security and Net Zero (DESNZ) published final reports on July 24, 2026 from seven first-of-a-kind projects under its Longer Duration Energy Storage (LoDES) Demonstration Programme, which ran from 2021 to 2026. The UK long duration energy storage trials moved each project from feasibility study through to a working prototype, covering thermal storage, electrical storage and power-to-X technologies designed to keep renewable power available during extended periods of low wind, according to the gov.uk publication.
Energy Live News, which first reported on the final results on July 27, 2026, described the programme’s total value as around £70 million. The seven awards itemized on the gov.uk results page sum to approximately £51.7 million; the remainder of the stated £70 million total is not itemized on that page and likely reflects earlier Phase 1 feasibility funding and a separate Stream 1 of the programme not covered in the Stream 2 Phase 2 results. No DESNZ ministerial quote accompanied the published results.
What the seven long-duration energy storage projects tested
Sunamp’s EXTEND project, backed by £9.25 million, combined thermal batteries with smart heating controls and was trialled in 100 UK homes. StorTera’s Sustainable Single Liquid Flow Battery, funded with £5.02 million, used a lithium-sulphur chemistry built from recyclable materials and wood industry by-products; eight modules were combined into a 200kW/1.6MWh demonstrator at the Midlothian Innovation Centre outside Edinburgh.
Other projects included the University of Sheffield’s ADSorB modular heat storage system (£2.6 million), EDF R&D UK’s HyDUS hydrogen storage project adapting metal hydride technology from the fusion industry (£7.73 million), RheEnergise’s High-Density Hydro dense-fluid pumped storage demonstrator (£8.24 million), SynchroStor’s pumped thermal storage demonstrator (£9.44 million), and Cheesecake Energy’s FlexiTanker, which pairs thermal and compressed-air storage at a Colchester microgrid with up to 8MW of solar generation (£9.45 million).
| Project | Developer | Funding | Technology | Demonstrator |
|---|---|---|---|---|
| EXTEND | Sunamp Ltd | £9.25m | Thermal storage | Trialled in 100 UK homes |
| ADSorB | University of Sheffield | £2.6m | Thermal storage | Prototype at Univ. of Nottingham’s Creative Energy Homes campus |
| HyDUS | EDF R&D UK | £7.73m | Hydrogen (power-to-X) | Metal hydride storage adapted from fusion research |
| SLIQ | StorTera | £5.02m | Flow battery | 200kW/1.6MWh demonstrator near Edinburgh |
| High-Density Hydro | RheEnergise | £8.24m | Dense-fluid pumped hydro | 250kW/1MWh (4-hour) demonstrator |
| PTES Demonstrator | SynchroStor | £9.44m | Pumped thermal storage | Grid-connected, 10-hour storage |
| FlexiTanker | Cheesecake Energy | £9.45m | Thermal + compressed air | Colchester microgrid with up to 8MW solar |
The programme’s aim, per DESNZ, was to accelerate innovative long-duration storage technologies from feasibility study to full-system prototype so they could later attract commercial investment. None of the seven demonstrators is yet a commercial-scale deployment; each remains at prototype stage following the trials.
The results add to a wider set of long-duration storage technologies winssolutions.org has tracked this year, including iron-air batteries and a zinc slurry battery that ran for 5,128 hours in a Nature Energy-published test, both aimed at the same gap the UK trials target: storing renewable power for days rather than hours.
Background
The Longer Duration Energy Storage Demonstration Programme was established by the UK government (initially under the Department for Business, Energy and Industrial Strategy, later transferred to the Department for Energy Security and Net Zero) to fund technologies capable of storing electricity for periods beyond the few hours typically served by lithium-ion batteries. The programme’s Stream 2 supported seven projects through a two-phase process, Phase 1 feasibility studies followed by Phase 2 prototype demonstration, running from 2021 to 2026. The gov.uk results page listing the seven awards was first published in November 2022 and updated on July 24, 2026 to add each project’s final report, marking the formal close of the demonstration phase and a decision point for the UK on which of these technologies to support toward commercial deployment.
Sources: UK Department for Energy Security and Net Zero (gov.uk); Energy Live News; No2NuclearPower
Featured image: photo by Petr Ganaj on Pexels (free Pexels license).
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I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.
