1. 1 A Review of Impacts to UFE and Load Ratio Share Based on AV Profile ID Changes Presented by ERCOT Staff to the Profiling Working Group 10/26/2005

2. 2 Run Test Settlements to See Effects of AV Prepare test environment to run settlements for different scenarios Select a sample of 30 (or so) days to analyze Run test settlements with currently assigned Profile IDs and capture results In test environment, change Profile IDs as directed by the Annual Validation Process Run test settlements with changed Profile IDs and capture results Compare changes in UFE and Load Ratio Share

3. 3 Which Days to Analyze? Created ERCOT-wide Residential load profiles Weighted Weather Zone load profile by ESI ID counts Considered Heating Degree Days and Cooling Degree Days Looked at daily kWh as a percentage of monthly kWh Ultimately segmented based on the following ratio: RESHIWR daily kWh / RESHIWR monthly kWh RESLOWR daily kWh / RESLOWR monthly kWh

4. 4 Selecting Days to Analyze

5. 5 How do the Profile ID changes affect UFE?

6. 6 UFE for Trade Date 12/23/04 (Stratum 3)

7. 7 UFE for Trade Date 11/16/04 (Stratum 1)

8. 8 UFE for Trade Date 04/27/05 (Stratum 2)

9. 9 UFE for Trade Date 02/11/05 (Stratum 3)

10. 10 Mean Abs. Percentage Point Change in UFE

11. 11 UFE in MWh

12. 12 How do the Profile ID changes affect Load Ratio Share?

13. 13 Change in Load Ratio Share and MWh

14. 14 Change in Load Ratio Share and MWh

15. 15 Change in Load Ratio Share and MWh

16. 16 Change in Load Ratio Share and MWh

17. 17 Change in Load Ratio Share by LSE Size

18. 18 Change in Load Ratio Share by LSE Size

19. 19 Change in Load Ratio Share by LSE Size

20. 20 Change in Load Ratio Share by LSE Size

21. 21 Change in Load Ratio Share for One LSE

22. 22 Change in Load Ratio Share for One LSE

23. 23 Change in Load Ratio Share for One LSE

24. 24 ERCOT LP Staff’s Recommendations Those ERCOT guys sure seem to know what they’re doing... Proceed with submission of 2005 Annual Validation Profile ID changes Continue PWG-sponsored efforts to improve the Profile Type assignment algorithm Continue consideration of shifting Profile Type calculation responsibilities to ERCOT primarily to allow use of several years worth of data in the algorithm