NESO's support for Ofgem's assessment of Long Duration Electricity Storage (LDES) projects
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We are working closely with the National Energy System Operator (NESO) to support delivery of the Long-Duration Electricity Storage (LDES) scheme under a cap and floor regulatory regime.
Ofgem retains responsibility for designing and delivering the scheme.
NESO is providing independent, technical support across several areas of Window One. This includes determining the level of storage capacity to be supported, validating applicants’ connection status, and conducting detailed cost-benefit analyses and evaluating the wider system impacts of proposed projects.
These two letters outline the agreements in place for NESO's work on the Long Duration Electricity Storage (LDES) programme.
Main document
[NESO's support for Ofgem's assessment of Long Duration Electricity Storage (LDES) projects [PDF, 195.12KB]
Subsidiary documents
[Confirmation of NESO’s support to Ofgem’s Assessment of Long Duration Electricity Storage (LDES) projects [PDF, 65.89KB]
](https://www.ofgem.gov.uk/sites/default/files/2025-08/NESO%20LDES%20Letter.pdf)