P503 Balancing and Settlement Code (BSC) changes
- Publication type:
- Code modification
- Publication date:
- Topic:
- Metering, Energy codes
- Subtopic:
- Smart meters, Balancing and settlement code (BSC)
- Industry sector:
- Supply and Retail Market
Outcome of changes to Balancing and Settlement Code (BSC) P503, unfreezing specific Market Domain Data (MDD) Entities temporarily to enable load diversity under the BSC.
Details of outcome
Ofgem has approved BSC Modification Proposal P503, which unfreezes specific MDD Entities to safeguard consumers in Northern Scotland against power outages or usage reductions during the 2025/26 Winter period. Under the new arrangement, suppliers operating in Northern Scotland will be able to introduce variance in the peak/off-peak switching times for Economy 10 tariffs, maintaining the stability of the electricity grid in the area.
Start date
The implementation date for Modification Proposal P503 is 15 December 2025.
Code modification description
Modification P503 was proposed by OVO, and Ofgem was requested to grant Urgent status to the modification. The proposal was granted Urgent status on 7 November 2025. The modification seeks to reduce peaks in demand by creating new Standard Settlement Configurations (SSCs) and Time Pattern Regimes (TPRs) by temporarily unfreezing Market Domain Data (MDD) Entities. The change was requested to introduce diversity in off-peak timings, protect consumers in Northern Scotland from electricity supply restrictions, and maintain tariff choice for former Radio Teleswitch (RTS) consumers.