Future Arrangements for System Services – DASSA Volume Forecasting Methodology Decision Paper
The SEM Committee today, 24 March, 2025, publishes its decision on the Future Arrangements for System Services DASSA Volume Forecasting Methodology. This decision is made by reference to a public consultation held by the TSOs and a subsequent Recommendations Paper submitted by the TSOs on 31st of January 2025.
Overall, the SEM Committee considers the Volume forecasting methodology to be an appropriately conservative approach for the initial operation of DASSA. However, the SEM Committee require the TSOs to improve volume forecast based on experience and improved understanding of system needs. The SEM Committee welcomes the TSOs commitment to create indicative forecasts for Y+10 and Y+2 and detailed forecast for Y+1.
The SEM Committee considers that the TSO proposal to procure volumes to maintain system frequency band range within 49.9 – 50.1 Hz for 98% of the time as per the CRU’s PR5 Incentives and Reporting framework is not the appropriate reference for setting the volumes. The SOGL requirement is 49.8 to 50.2 Hz and volumes should be procured to maintain this frequency range.
Following on from this, the TSOs will review the Grid Code, system services code and the licensing of the TSOs. In addition, the TSOs should update the PIR based on the additional consultation and workstream requirement as per this Decision.