Review of Demand Estimation Times for Modification Proposal 461 Meeting Monday 5th August 2013 Hayley Burden

Methodology In each of the identified processes the following occurrences were reviewed (where applicable); The last occurrence D-1 The first occurrence D The last occurrence D Assessment made to understand if the occurrences could: retain their current time be moved by an hour totally removed an additional occurrence inserted This assessment was then used to populate UNC line by line review spreadsheet

Demand Estimation - Background UNC and Process Times for Demand Forecasts DNO’s submit LDZ Demand forecasts to NTS (automated via aggregator). Gemini uses the LDZ forecast information in conjunction with LDZ DM shipper nominations to derive, on behalf of shippers, NDM nominations/allocations (NDMA process) Interrelationship between weather data, LDZ Demand Forecasts and Non-Daily Metered Attribution (NDMA) process runs UNC (latest time) Current Run Time Time Difference D-1: 14:00 D-1: 13:00 1 hour D-1: 18:00 D-1: 16:00 2 hours D-1: 02:00 D-1: 00:00 D: 12:00 D: 10:00 D: 15:00 D: 13:00 D: 18:00 D: 16:00 D: 21:30 D: 20:45 ¾ hour D: 02:00 D: 00:00

Relationship with NDMA UNC and Process Times for NDMA NDM Demand attribution is the process by which LDZ forecast demand is attributed to individual NDM shippers. The NDMA process is run following receipt of DN provided LDZ demand forecasts Therefore there is a dependency (subject to MOD453 Nexus) between these two processes If the times of LDZ demand forecasts change, it is recommended, but not essential, that the NDMA times should also move. UNC (latest time) Current Run Time Time Difference D-1: 14:00 D-1: 13:05 1 hour D-1: 18:00 D-1: 16:00 2 hours D-1: 02:00 D-1: 00:00 D: 12:00 D: 10:00 D: 15:00 D: 13:00 D: 18:00 D: 16:00 D: 21:30 D: 20:45 ¾ hour D: 02:00 D: 00:00

Results Overview Demand estimation processes are strongly interlinked to other related processes, therefore a time move of one process will have a knock-on effect to others Demand estimation is highly dependent on the input of the DNOs from their own internal processes to produce the data Recommended that the current run times for demand estimation and related processes should remain AS-IS in the new Gas Day Although not recommended, even if a full lift and shift approach was adopted, only a few system changes would be required as most of the processes are run more than 1 hour before the UNC deadline What are the views of Mod 461 WG members?

Other Considerations NDMA and the EU Balancing Code The current NDMA run time of D-1 14:00 is not compliant with the EU Balancing Code The EU Balancing Code states that Transmission System Operators must complete a NDMA run at D-1 12:00 NG NTS assessing options on how to achieve compliance with the EU Balancing Code (industry input will be required) The assessment of current NDMA times by the Mod 461 Workgroup may inform the solution to the EU Balancing Code change but only if a change is proposed

Other Considerations Project Nexus – Modification 453 Demand Estimation NG NTS have met with Mod Proposer and Xoserve who confirmed that no demand forecast time changes are proposed as part of this modification Workgroup for Modification 461 to keep in view developments of Modification 453 and share information if any time changes are proposed