CMP466: CMP456 Consequential Charging Modification
What is being proposed
GC0168 requires existing plan, upon request to obtain and submit Electro Magnetic Transient (EMT) models. This is a significant and costly challenge for older plant with complex systems and with little direct benefit to the Generator. This modification enables appropriate cost recovery.
Current status
Proposal raised on 13 November requencing urgency. A special CUSC Panel is scheduled for 21 November 2025 where the CUSC Panel will determine the governance route. The Proposal was presented at the CUSC Panel on 12 December whereby the Panel by majority agreed that CMP466 did not meet the Authority’s Urgency criteria (a) and therefore did not recommended urgent treatment. Panel’s recommendation was sent to the Authority on 12 December 2025 seeking an decision by 5pm on 19 December 2025. (21/01/2026) On 19 December 2025 the Authority rejected that CMP466 should be progressed on an urgency basis and should follow the standard timeline set out in the Panel's letter. (05/02/2026) The CUSC Panel carried out a deep dive of the prioritisation stack and the Panel agreed that similarly to CMP456, CMP466 should be assigned as a high priority. Majority of Panel members agreed that the unexpected financial impact to generators along with a simplistic solution meant this could be progressed quickly and align with GC0168.
Details
Timeline
Analysis
CMP466 enables generators to recover costs of providing Electromagnetic Transient (EMT) models required under Grid Code GC0168. The modification follows after CMP456 and addresses the financial burden placed on existing generators, particularly older plant with complex systems. CUSC Panel initially rejected urgency but assigned high priority status on 5 February 2026.
Why it matters
This shifts EMT model costs from generators to system users, creating a precedent where new technical requirements imposed by the system operator become socialised costs rather than sitting with asset owners. The modification recognises that older generators face disproportionate costs for little direct benefit, as such it transfers value from those who use the system to those who must comply with new technical standards.
Key facts
- •Proposal raised 13 November 2025
- •Authority rejected urgency on 19 December 2025
- •CUSC Panel assigned high priority status 5 February 2026
- •Relates to GC0168 EMT model requirements
- •Particularly affects older plant with complex systems