Government pushes Strategic Spatial Energy Plan deadline back a year to end of 2027

The Department for Energy Security and Net Zero (DESNZ) has formally extended the deadline for the National Energy System Operator (NESO) to submit the first Strategic Spatial Energy Plan (SSEP) by a year, to 31 December 2027.

The department confirmed the new date in a letter to NESO, published on GOV.UK on 23 October 2026. A separate direction moves the submission deadline from 31 December 2026 to 31 December 2027 and applies to England, Scotland and Wales.

DESNZ said the extension formally reflects a timeline revision first set out on 4 December 2025. According to the department, updated cost and demand data are being incorporated into the SSEP modelling, and the purpose of the update is to maintain the quality and credibility of the plan.

Julian Leslie, Director of Strategic Energy Planning at NESO, said when the revised timetable was announced in December 2025: "NESO remains committed to ongoing engagement and openness throughout this process."

Why the plan slipped

NESO said in December 2025 that it and DESNZ had decided to re-run the SSEP modelling using the latest data, after assessing the impact of refreshed energy generation cost data on its delivery timelines. DESNZ's own page refers to both cost and demand data being brought into the modelling.

Under the revised programme NESO set out at the time, pathway options were to be submitted for decision by the Secretary of State for Energy Security and Net Zero in summer 2026, with public consultation on the draft SSEP in early 2027 and the final plan delivered in autumn 2027. The formal direction published this week sets 31 December 2027 as the formal deadline for submission.

The pathway options milestone had already moved once. When NESO published the SSEP methodology on 15 May 2025, following approval from the Secretary of State and Ofgem, it planned to submit pathway options in the fourth quarter of 2025.

What the SSEP is

The SSEP is intended as the first high-level blueprint for Great Britain's energy infrastructure from 2030 to 2050, according to NESO. The first plan focuses on electricity generation and storage and hydrogen assets, DESNZ said when it commissioned the work.

When the UK government announced the commission in October 2024, it said the first iteration of the plan would be published in 2026. It said a more strategic approach would help cut grid connection waiting times and reduce overall system costs.

Michael Shanks MP, Minister for Energy, said at the time: "Delivering the country's first ever spatial plan will be a major milestone for our new public energy body."

Knock-on effect on network plans

The later SSEP has already pushed back the network planning that depends on it. NESO said in December 2025 that delivery of the Centralised Strategic Network Plan (CSNP) and the Regional Energy Strategic Plans is now planned by the end of 2028.

Ofgem followed on 15 April 2026 with a direction requiring NESO to submit the first CSNP to the regulator by 15 September 2028 and publish it by 15 December 2028. NESO had written to Ofgem on 23 March 2026 asking for derogations from its licences to move those dates from 30 June 2027 and 31 December 2027 respectively.

Ofgem said it had decided to align the CSNP timeline with the recently revised SSEP timeline. The regulator said the change would allow timely and adequate stakeholder input, enough time to develop network options, and certainty on long-term network needs.

In the meantime, NESO said the refresh of the second Transitional Centralised Strategic Network Plan would be delivered by 30 June 2026.

What happens next

On NESO's December 2025 programme, the next public step is consultation on the draft SSEP in early 2027, with the final plan due in autumn 2027 and the formal submission deadline now fixed at 31 December 2027. The first CSNP is due to be published by 15 December 2028.