GC0139: Enhanced Planning Data Exchange to Facilitate Whole System Planning
What is being proposed
This Modification seeks to increase the scope and detail of planning - data exchange between DNO's and ESO to help facilitate the transition to a smart, flexible energy system.
Current status
The Panel met in March 2020 and agreed that it goes to a Workgroup. Workgroup meetings commenced on 6 May 2020. The GC0139 timetable is dependent on the CIM governance group completing their work and on 10 January 2022, Ofgem published their open letter on CIM Governance. Following the publishing of the letter, Workgroup meetings recommenced on 30 March 2022. In May 2022 the Workgroup moved back two of their meetings to allow time to develop their legal text ahead of their Workgroup Consultation. A new timeline was approved at the July 2022 Grid Code Review Panel. New timeline approved at the January 2023 Grid Code Review Panel. A new timeline was presented to the August 2023 Grid Code Review Panel which was approved. A new timeline was presented to the September Grid Code Review Panel which was approved. A new timeline was approved at the February 2024 Grid Code Review Panel Meeting. A new timeline was approved at the April 2024 Grid Code Review Panel. The August 2024 Grid Code Review Panel approved a 3 month timeline extension. The Workgroup Consultation was issued on 17 December 2024, closed on 21 January 2025 and received 7 responses. The Workgroup Vote was held in November 2025. The Workgroup Report was presented to the December Panel meeting, where the Panel agreed the Terms of Reference had been met. The Code Administrator Consultation closed on 06 February. The DFMR will be presented at the February GCRP. 09/03/2026 At the February Panel it was concluded that in order to complete the Panel Recommendation Vote, Workgroup agreement was required to proposed legal text changes, so the DFMR will come back to Panel.
Details
Timeline
Analysis
Grid Code modification GC0139 expands data exchange requirements between distribution network operators and NESO for system planning. The modification has been under development since 2020, with workgroup consultation closing January 2025 and panel recommendation vote pending workgroup agreement on legal text changes. High impact parties include NESO, transmission owners and distribution network operators.
Why it matters
This creates administrative process for better data sharing rather than pricing information asymmetries between network layers. The four-year development timeline reflects the complexity of coordinating planning data across fragmented network governance — a symptom of the structural problem that distribution and transmission planning remain separate rather than integrated through common price signals.
Key facts
- •Workgroup consultation closed 21 January 2025 with 7 responses
- •Modification in development since March 2020 panel meeting
- •Cross-code impact includes STC (STCP19-5)
- •Panel recommendation vote requires workgroup agreement on legal text changes