1. Load Profiling Working Group RMS Presentation 8/01/2002 by Ernie Podraza Reliant Energy Retail Group Chair PWG

2. 2 Initial Validation Process Update Targets –Complete Profile ID assignment changes. –Due date was 6/15/02. Part of resettlement of True-ups. Beginning 7/31/01 trade day.

3. 3 Initial Validation Process Update TDSP Transaction Submittal Status Updated as of 3 PM, 7/31/02.

4. 4 Initial Validation Process Update ERCOT Validation Analysis of Sample Updated as of 4 PM, 7/31/02.

5. 5 Initial Validation Process Update Summary of PWG Completion Criteria Updated as of 4 PM, 7/31/02.

6. 6 Initial Validation Process Update TDSP Profile Change Efforts To Date –More than 700,000 814_20 transactions submitted. –A huge amount of work has been completed. Internal software development changes. Algorithm development and refinement. Approximately 12 Initial Validation Sub-team meetings. Frequent communication with ERCOT. –High Confidence level that the algorithms are correct. –Discrepancies have been identified.

7. 7 Initial Validation Process Update Issues –Difficult to distinguish initial validation transactions from normal business transactions so tracking the status is difficult. –Validation error percents may not reflect the final legitimate discrepancies. –Final discrepancies are being worked currently.

8. 8 Initial Validation Process Update Root Cause of Discrepancies –Profile Group (Residential or Business) not matching ESI ID type. –Some data not in sync between TDSP and ERCOT. Meter read dates in particular. –Interpretation of assignment of profile id on customer level vs. premise level.

9. 9 Initial Validation Process Update Current Status as of 7/31/02 –ERCOT June 29 validation run. –Some improvement in error percents. Discrepancies identified. Ongoing daily reviews with TDSPs. Will have another validation update after new 814_20s. –TDSP Reliant and TNMP must run refined algorithms over population. Resubmitting needed for 814_20 transactions. –Reliant may have as many as 100,000 more perhaps this week. –TNMP may have as many as 70,000 more. On going daily reviews with ERCOT to reconcile discrepancies.

10. 10 For RMS Vote PRR Extension of IDR Proxy Day Method

11. 11 For RMS Vote PRR Extension of IDR Proxy Day Method

12. 12 For RMS Vote Process: IDR Estimates

13. 13 For RMS Vote MARKET NOTIFICATION OF SYSTEM CHANGE PIP Number(s): N/A PRR Number(s): N/A Change Description: Changes to IDR data estimation using the BUSIDRREQ profile Protocol Section(s): 11.3.3 Interval Consumption Data Estimation Implementation Date: July 26, 2002 (Trade Day) Description of System Change: Effective Friday July 26, 2002, each interval for the BUSIDRRQ load profile will be multiplied by a factor of 0.758. This profile will be used in settlement only when an IDR ESI ID has no 15-minute interval data available for the period that covers the past 8 weeks. This change to the BUSIDRRQ load profile was approved by the Profiling Working Group during the IDR Default Profile Workshop held on July 15, 2002.

14. 14 For RMS Vote PRR Extension of IDR Proxy Day Method –From last 8 weeks to last 12 months. –11.3.3.3 Non-Weather Sensitive (NWSIDR) Proxy Day Method For ESI-IDs designated as NWSIDR, ERCOT will use a method for proxy day determination. This method incorporates the following. 1)If there is no historic interval data available according to (1) above, the IDR data will be estimated using the default profile assigned to the ESI ID for the trade day. 2)Use the most recent proxy day for which data is available as the estimate for the target Operating Day. From historical ESI-ID-specific interval data, choose the most recent occurrence of the appropriate day of the week (Su, M, T, W, Th, F, Sa) corresponding to the day of the week of the Operating Day (Holidays are treated as Sundays) within the most recent 12 months of the trade day;