RbD Subgroup Dean Johnson 8 th April 2008 RbD Subgroup Dean Johnson 8 th April 2008

Agenda RbD Verification Update Presentation of updated analysis Discussion of declining DMP sample Options available RbD Forecasting

RbD Verification Analysis Analysis period reflective of MOD152V timescales (Apr-04 to Mar-08) Trend – avg. cumulative over bill per DMP customer of 1,293 kWh for the period (323 / year) BUT: Recent trend indicates an under bill per SSP customer (cumulative difference) Pending analysis and receipt of further reconciliation and DMP data (up to 6 months) Per DMP Customer: Cumulative Billed, Actual & Difference (Billed-Actual)

RbD Imbalance – Causes Billed-Actual Difference LDZ Current Balance (TWH) Theft Of Gas Threshold Crossers Shrinkage Adjustment LDZ Adjustment Duplicates Late Confirmed Inter LDZ Transfers LDZ Postcode Discrepancy 2005 Postcode Discrepancy Remaining Balance (TWH) % Throughput 2004 (No Adjust) 2005 (No Adjust) 2006 (No Adjust) 2007 (Adjust to Flow) EA % EM % NE % NO % NT % NW % SC % SE % SO % SW % WM % WN % WS % Wales % Total %  Items removed or adjusted to reflect the amended analysis period (MOD152: 4 years) 4 Year History (April 2004 to March 2008)

RbD Imbalance Summary LDZ March 2008 (>Apr04)September 07 (>Oct 03)February 2007 (>Feb98) Current Balance Summary No Return Summary Yet To Flow Remaining Balance % of Throughput Remaining Balance % of Throughput Remaining Balance % of Throughput EA % % % EM % % % NE % % % NO % % % NT % % % NW % % % SC % % % SE % % % SO % % % SW % % % WM % % % WN % % % WS % % % Wales % % % Total % % % Imbalance current TWH - reduction from previous (21.64TWH – September 07) Comparison: Mar08 / Sep07 / Feb07

Declining DMP Sample Size  BGT DMP sample utilised in RbD Verification process from February 1998  50% reduction in sample size since DMP inception  Significant reduction since 2004, more apparent in last 1 to 2 years  Potential issues regarding confidence in RbD verification results… Feb98 10,689 Jan08 5,094

Declining DMP Sample Size  DMP sample of 10,000 meter points represents a 0.95% margin of error  i.e. The results presented are accurate to within +/- 0.95%, 95% of the time  Current DMP sample size is 5,094  Represents 1.37% margin of error  DMP sample is imperative to the RbD verification process  Confidence in results not currently regarded as an issue  BUT – sample reduction needs to be addressed and maintained going forward  Additional interest is being placed on verification results  Headings quoted - MOD194 ‘Correct Apportionment of NDM Error – Energy’  xoserve & BGT have discussed the DMP sample issues  Options are available to address the declining DMP sample numbers…

Declining DMP Sample Size: Options  Option 1: BGT to boost DMP sample numbers  BGT solely responsible boost and maintain going forward  Option 2: Additional Shipper involvement  Additional samples from customer base, replicate BGT established process  Option 3: Do nothing  Sample numbers still good, error margin good, but sustainable?  Option 4: Transporters / xoserve run own DMP sample  Central operation and maintenance  Option 5: Combine DMP with Demand Estimation data recorder sample  Established sample - 3,440 data recorders currently installed on SSP sites  Manual collection twice a year – used in deriving NDM Algorithms for allocation  Combined; 8,600 sample (1.06% margin of error)  Available data allows initial analysis - indicates following results…

Declining DMP Sample Size: Data Recorders  Identify billed values and actual value for recorders (replicate DMP analysis)  Data recorder analysis shows a different trend to DMP  DMP indicates SSP Billed >Actual (over): DR indicates SSP Billed < Actual (under)  Further investigation required, data available May Cumulative Billed, Actual & Difference (Billed-Actual) Per DR Customer

DMP Sample Size – Declining: Options  RbD Sub Group to consider options:  Option 1: BGT to boost DMP sample numbers  Option 2: Additional Shipper involvement  Option 3: Do nothing  Option 4: Transporters / xoserve run own DMP sample  Option 5: Combine DMP with Demand Estimation datarecorder sample