A key element of the C2C project was to explore the interaction between DSR services and existing industry policy, more specifically the network planning requirements in ER P2/6. ER P2/6 stipulates the security of supply to customers based on the aggregation of their demand as it appears on the network. In its simplest form the recommendation sets out the amount of capacity that must be available on the network for specified demand thresholds, so that demand can always be supplied when capacity becomes unavailable due to a fault or a planned outage.
As C2C uses this inherent latent capacity specified as a requirement of ER P2/6 for the connection of new demand, there will be instances following an outage and prior to network switching when customers’ unconstrained demand cannot be supported leading to a potential non-compliance under the current framework. For the purposes of the C2C trial a derogation from the requirements of P2/6 was granted for all demand groups supplying the trial circuits.
The remit of this area of work within the project was to present a recommendation for how DSR could be accommodated within ER P2/6 and to provide a consistent and practical approach for the industry to follow when assessing the contribution of DSR to security of supply assessments.
It was proposed that:
In the short term an appropriate allowance for DSR should be taken into account when calculating group demand or by adjusting network capability. It is up to each DNO to justify and formally record its approach for each DSR connection.
It is up to each individual DNO to decide on the percentage of DSR that it will take into account when calculating group demand and this value should be recorded.
At this current time it is the view of the industry that for EHV networks the gross level of demand (group demand plus the responsive demand) should be curtailed to ensure that the system is able to maintain supplies to customers while responsive demand is disconnected.