The shortlist includes projects with a combined capacity of 7.6GW across four technologies: pumped storage hydro, compressed air energy storage, lithium-ion batteries and vanadium redox flow batteries. They are intended to provide the longer-duration storage needed to help balance electricity supply as increasing amounts of renewable generation are connected to the grid. The projects were selected from 77 eligible applications representing around 27GW of proposed capacity.

Ofgem said the portfolio had been structured to provide an appropriate mix of technologies, storage durations and geographic locations. The energy regulator opted for capacity at the upper end of its original target range, recognising that some schemes may not ultimately go ahead while aiming to ensure sufficient storage capacity is delivered.

The full list of LDES projects provisionally selected for Ofgem support, listed in consultation documentation

Source: Ofgem  
 

Unlike shorter-duration batteries that typically respond over minutes or a few hours, LDES functions over a timescale of eight hours or more, allowing larger volumes of renewable electricity to be shifted across extended periods. According to Ofgem, wider deployment could ease pressure on transmission and distribution networks while reducing the need for costly network investment and constraint management.

Akshay Kaul, Director General for Infrastructure at Ofgem, said: ‘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.’

The investment support scheme uses a cap-and-floor mechanism designed to give developers greater revenue certainty while protecting consumers. Projects are guaranteed a minimum level of revenue if returns fall below an agreed threshold, while revenues above the cap are shared with consumers.

Sam Hollister, Head of UK Market Strategy at LCP Delta, said technologies capable of shifting electricity across hours and days would become increasingly important as renewable generation expands.  

‘Today’s announcement marks an important milestone for long-duration energy storage in Great Britain. As renewable generation continues to grow, technologies that can shift large volumes of electricity across hours and days will become increasingly important in maintaining security of supply and minimising system costs,’ he said.

Consultation on Ofgem’s provisional decisions will remain open until 7 August 2026, with a final decision expected later this year. Applications that are not selected in the first round may still compete for support in future or go ahead without support on a merchant basis.