Pumped hydro and lithium BESS top UK LDES cap and floor

Ofgem has revealed the 16 projects that have been provisionally selected for support through the first LDES cap-and-floor tender, chosen from a shortlist of 77 projects selected in September 2025.

First announced in October 2024, the cap-and-floor scheme is intended to de-risk investment in UK LDES projects by offering revenue certainty via a floor price for successful projects.

Pumped hydro was the top technology in power terms, with the proposed 600 MW Loch Hemp Storage, 1.4 GW Coire Glas, and 400 MW Earba projects all selected by Ofgem. With a combined power output of 3.6 GW, the 11 BESS projects selected made lithium-ion the second most successful technology.

Compresses air-energy storage (CAES) and vanadium flow redox batteries were also chosen in the first LDES tender round. The 50 MW TeesCaes project in north England and the 65 MW Frontier Legacy vanadium flow redox battery have both been chosen by Ofgem – in keeping with the regulator’s brief of maintaining some technological diversity in the mix.

Project dispatch durations range from eight hours to 32 hours, and the top 10 projects all had durations exceeding 12 hours. By region, projects in north Scotland – where there is significant wind curtailment – account for 5.1 GW of the power output and roughly 80% of energy storage capacity.

Akshay Kaul, director general for infrastructure at Ofgem said the regulator was creating infrastructure for “renewable energy to thrive.”

“It’s fantastic to see such a wide range of technologies coming forward. This takes us a step closer towards the long-duration energy storage we need in a clean power system to maintain secure supply during periods of cold, hot, still or cloudy weather when solar or wind power output may be low.”

Ofgem’s decision is provisional and the energy regulator has opened a consultation on its minded-to decision that will run until August 7. The first ever UK cap-and-floor application window for LDES attracted bids from 171 applicants in summers 2025.