This page provides full details of the proposed change, relevant dates and decisions.

What is the issue?

CM Rule 13.4.1B allows Capacity Providers to aggregate delivered capacity across a group of Capacity Committed Capacity Market Units (CMUs) with the same Capacity Provider to allow for better flexibility in meeting the Satisfactory Performance Days (SPD) obligation by delivering as a CMU Portfolio.

What is the proposed solution?

CP377 proposes to amend Rule 13.4.1B to allow CMU Portfolios to be formed across Company Groups.

Title Decoration

Diagram of CMAG Rule Change Proposal stages: Submission, Scheduled, CMAG development, Consultation, With Ofgem, Implemented.CMAG development phase

This is the stage after the CMAG has initially considered the CM Rule Change Proposal and has determined that further assessment is required of the proposal. Activities in this stage may include the development  of possible solution options, the development of legal text for a proposal and/or the consideration of the impacts of a solution on relevant stakeholders.

Proposer: EMR DB Type of change: Amendment Date Raised: 09 April 2024 Category: Assurance

Next Steps
Title Decoration

Milestone Date
Proposal Form Submission 9 April 2024
CMAG Initial Consideration Meeting 19 (16 April 2024)
CMAG Development Meeting 19 (16 April 2024)
CMAG Recommendation to Ofgem Meeting 19 (16 April 2024)
Ofgem Statutory Consultation TBC
Implementation TBC

Impacts and Related Changes
Title Decoration


Capacity Market Rules Sections

  • Rule 13.4.1B – Amendment

Impacted Parties

  • Capacity Providers

Related Changes


Contact information
Title Decoration

Lead Analyst:
Amy Stackhouse, Change Lead: Capacity Markets
[email protected], 020 7380 4221