CMP426: TNUoS charges for transmission circuits identified for the HND to add capacity across boundaries
What is being proposed
To consider the cost recovery for circuits being classified as boundary reinforcement within the Holistic Network Design (HND). Ensuring the purpose and function of circuits classified as boundary reinforcement are considered when determining the appropriate TNUoS tariff and users the costs are recovered from.
Current status
Proposal issued to the December 2023 CUSC Panel. The December 2023 CUSC Panel unanimously agreed that CMP426 should follow the Standard governance route and proceed to a Workgroup. The Panel approved the Terms of Reference for the Workgroup. Workgroup nominations closed on 12 January 2024 and Workgroup meetings commenced from 05 February 2024. Ahead of the CUSC Panel approving the reconvening of Workgroup meetings, the ESO is completing further analysis which will be available early Summer 2024. October 2024 CUSC Panel prioritised the modification as High. Upon receipt of the Authority Open Letter on 31 January: Outlining their approach to prioritisation of electricity transmission network charging modifications, Panel will review the modification status in the February Panel. (18/02/2025) On 14 February 2025 at the Special CUSC Panel the Panel discussed, at length and in detail, the prioritisation of CUSC Modifications. The CUSC Panel agreed this modification be placed as "Medium to High" in the prioritisation stack.
Details
Timeline
Analysis
CMP426 proposes changing how TNUoS charges are allocated for transmission circuits classified as 'boundary reinforcement' within NESO's Holistic Network Design. The modification has been prioritised as 'Medium to High' by the CUSC Panel following an Authority open letter on transmission charging prioritisation in January 2025. Workgroup analysis resumed in early 2024 after initial delays.
Why it matters
This addresses a cost allocation gap where boundary reinforcement circuits may not sit with appropriate users under current TNUoS methodology. The modification sits in a complex prioritisation queue following Ofgem's guidance on charging reforms, suggesting systematic review of transmission cost recovery is underway.
Key facts
- •Workgroup analysis delayed until Summer 2024
- •Panel prioritised as 'Medium to High' in February 2025
- •Authority open letter on charging prioritisation issued 31 January 2025
- •Medium impact on NESO and TNUoS-liable parties