NGET - Capacity Market Rules CP324
Change Proposal
Publication date
Rule 8.4.6(d) requires an active CMN to be cancelled once the automated system margin calculation in the next 4 hours show no breaches of a 500MW threshold. For a DCI (Demand Control Instruction) or Low Frequency triggered CMN it is unlikely that the data utilised by the automatic CMN calculation will be updated before the calculation is executed. This means that in all instances we would see such CMNs cancelled either in the same settlement period (SP) or the next SP (depending on when in the SP the CMN is published). Where NGET is issuing individual DCIs across multiple DNOs, the Industry could see CMNs being published, then cancelled and subsequentlypublished again. The System Operator part of National Grid’s business would therefore like consideration to be given to implementing a dead band (1, 1.5 or 2 hours) following the CMN publication when triggered by a DCI or Low Frequency event which would mitigate against the potential confusion and/or lack of confidence in the process.
Change proposal status
Under consultation
Proposal rules area
Obligations of Capacity Providers and System Stress Events
Proposal organisation
National Grid Electricity Transmission