​Ofgem announced its Minded-to decision on Long Duration Energy Storage (LDES) on July 21 2026. Subject to consultation, this awarded 7.6 GW and 136.9 GWh of Cap and Floor contracts across 16 projects, with 79% of the energy capacity awarded in North Scotland.

Ofgem procured the top of its target range of LDES capacity as it is expecting project attrition. By 2030, the operational timeline Window 1 requires, we expect 1.1 GW / 9.6 GWh of projects online. In our firm scenario, made of projects with planning, land and grid in place today, Modo Energy expects the LDES cap and floor to deliver 2.6 GW / 56 GWh by 2035. In our probable scenario, delivery is 6.5 GW / 114 GWh by 2036.

Key takeaways

• Of the 16 “minded-to” LDES projects, 9 currently hold full planning consent.
• Of the planning consents awarded, applications typically use a Rochdale Envelope, in which specific energy or power consents are omitted while the scheme finalises them; instead, a number of units or hectares of land is approved.
• The five Field projects have the highest GWh-per-hectare density, indicating they intend to use the most energy-dense BESS containers. While these may not currently be operational, multiple providers have catalogues for 8 MWh+ containers.
• One site holds a Gate 2 offer, and 7 sites hold Gate 1. The TEC register shows LDES grid capacity could reach 4.5 GW by 2030 and 7.1 GW by 2035.
• We provide several buildout scenarios. The firm scenario, made up of sites which currently have planning, grid and land, has 2.6 GW / 56 GWh of LDES online in 2035. The probable scenario adds sites which we consider likely to secure these by 2030, and has 6.5 GW / 114 GWh in 2036.

GB LDES batteries would be the largest lithium-ion batteries in the US, Europe and Australia

The Window 1 minded-to projects feature 11 lithium-ion batteries. If built, these assets will be among the biggest battery sites in the world and, by a long way, the largest in Great Britain. The chart compares the LDES batteries with the largest operational BESS sites in the markets Modo Energy tracks. We are aware that larger systems exist in Saudi Arabia and China, but their economics are very different from those in the markets shown below.

Given planning, grid and land availability, the analysis below gives sensitivities on how likely we think these sites (as well as the non-battery LDES bids) are to become operational. It does not consider individual project economics.

How many LDES sites could get built, and when?

Modo Energy separates the LDES projects into four buckets of likely delivery: firm, probable, possible and speculative.