Nexus Workgroup Read V alidation Scenarios

1. Nexus WorkgroupRead Validation Scenarios 4th December 2013

2. Background • Read Validation rules and tolerances developed during the Settlement BRD • Concern raised at 30th October workgroup that the tolerances may not be appropriate for Class 4 sites as a ‘flat profile’ is used (AQ / 365 x no. of days in period). • Workgroup agreed the principle of read validation was correct but would like to examine the tolerances further • The following slides provide a list of various scenarios considered by Xoserve during analysis of the AQ requirements to validate the principles & tolerances described in the BRD

3. Scenarios • AQ = 1 • Reason: the site has not been consuming gas for over 9 months • Consequence: read will fail validation • Outcome: AQ Correction process used to re-calculate the AQ then re-submit the read • AQ is significantly higher or lower than sites predicted consumption • Reason: change in plant or site previously ‘mothballed’ • Consequence: read may fail validation • Outcome: AQ Correction process used to re-calculate the AQ then re-submit the read

4. Scenarios cont. • Site Isolated • AQ would carry over until 9 months consumption was available during the non-isolated period therefore read would not fail • Vacant site • AQ would reduce as reads are loaded with zero/low consumption over a period • If read fails due to the AQ being low, the AQ Correction process to be used to amend AQ • Round The Clock value incorrect/not populated • Read would fail due to out of tolerance • Re-submit read with correct ‘Round the Clock’ (TTZ) count

5. Scenarios cont. • Change of Class – Class 4 to 2 • SOQ is used to validate the reads, Shipper nominates the SOQ • Change of Class – Class 2 to 4 • Daily reads previously loaded for site and AQ reviewed monthly. Reads should therefore pass the validations based on AQ