GSR035: System Access Reform: Review of the operational requirement in England and Wales.
What is being proposed
This modification is to review the operational criteria applicable in England and Wales for secured events of low probability and low impact to align with that of Scotland.
Current status
08/12/25 - Proposal raised on 06 November 2025 and was presented at the SQSS Panel on 05 December 2025. A revised Proposal to be circulated with suggested improvements for Panel approval. 02/02/26 - Proposal approved and proceeded to Workgroup nominations until 12/02/26 03/03/26 - First workgroup on 03 March 2026
Details
Timeline
Analysis
NESO proposes to align operational criteria for low probability, low impact secured events between England/Wales and Scotland through SQSS modification GSR035. The workgroup phase begins March 2026 following panel approval in February. This affects transmission security standards that determine when networks must be reinforced.
Why it matters
This harmonisation could reduce reinforcement requirements in England and Wales if they adopt Scotland's more relaxed standards for rare events. As such, it may defer network investment costs while creating regional consistency in planning standards.
Key facts
- •Proposal raised November 6, 2025
- •Panel approval expected February 2, 2026
- •First workgroup meeting March 3, 2026
- •Medium impact on TOs, NESO, DNOs, DCCs, OFTOs, interconnectors and generators
- •Potential changes required to Grid Code and STC