UNC 0407 Analysis Scope - Update Offtake Arrangements Workgroup – October 2012

Overview Analysis was scoped to identify any NTS investment costs associated with the implementation of UNC 0407 This analysis in the process of being completed by GL Noble Denton – delivery still as we outlined at July UNC Panel meeting Impact of the proposal to remove the 2hr 5% rule on the NTS effectively leads to an: increased lag between changes made at NTS offtakes and subsequent changes at entry points. This is covered by the NTS Design Margin as DN demand changes would be met through more rapid NTS/LDZ offtake changes. The NTS Design Margin is used within the system planning process to create operational linepack GL Noble Denton completed the last review of the NTS Design Margin in 2008

Impact of UNC 0407

Analysis Scope & Timeline GL Analysis based on implementation of Mod 0407 Repeat 2006-2008 flow margin analysis making appropriate adjustment to reflect the flow change driver referenced in 0407 Update analysis using recent NTS operational data to show the impact on Linepack and: how the issue is developing how behaviour is changing Update to include the potential change in behaviour that implementation of 0407 would allow Network Analysis to identify NTS Investment costs associated with any required increase to the design margin as a consequence of part 1.