ERCOT

1. ERCOT An Overview of the Implementation of New Profile Models

2. NIDR Profiling Methodology • (ESIID Usage / Profile Usage) * Profile Residential Example ESIID Usage for the time period 4/1/2006 through 4/30/2006 equals 1,500 kWh Profile Usage for the same time period equals 1,000 kWh Scale factor calculation: 1,500/1,000 = 1.5 Settlement value equals 1.5 * Profile 0:15 0:30 0:45 1:00 PROFILE DATA for 4/1/2006 0.32 0.32 0.30 0.28 SCALE FACTOR 1.5 1.5 1.5 1.5 SETTLEMENT kwh VALUE 0.48 0.48 0.45 0.42

3. Business High Load Factor • Example For Trade Day 4/30: • Most Current Read is 90,000 kwh for 3/15 – 4/15 • Assume the scaling factor is 1 • Trade Day 4/30 would be settled using a 1 scaling factor multiplied by the old profile of say 3,000 kwh for the entire day

4. Business High Load Factor

5. Business High Load Factor • Example For Trade Day 5/1: • New Profile Model Implementation Date of 5/1/2007 • Most Current Read is 90,000 kwh for 3/15 – 4/15 • Assume the scaling factor is 1 • Trade Day 5/1 would be settled using a 1 scaling factor multiplied by the new profile of say 1,500 kwh for the entire day

6. Business High Load Factor

7. Business High Load Factor • A direct cutover from the old profile model to the new profile model will result in the energy being assigned to the Business High Load Factor class being reduced by approximately 50% from 4/30 to 5/1.

8. Option 1 - Direct Cutover Challenge • The direct cutover option results in a significant change in energy assigned to both the business and residential customer classes. • This will result in a significant change in UFE.

9. Option 4 - Graduated Option • One way to mitigate the significant change in energy being assigned to the Business High Load Factor class is to use a graduated approach

10. Option 4 - Graduated OptionDefined • Implement the change from the current load profile models to the new profile models over a longer timeframe • Timeframe is “market defined” • Allows a maximum threshold for model changes from one day to the next

11. Option 4 - Graduated Option Defined • Business High Load Factor profile is created from the existing (old) load profile model • Business High Load Factor profile is also created from the new load profile model • The results from the two models are weighted in a manner that allows the change from the old profile model to the new profile model to be limited by a maximum threshold

12. Option 4 - Graduated Option Example • Example using a 20 day timeframe to migrate from the old profile model to the new profile model

13. Option 4 - Graduated Approach – Day 1

14. Option 4 - Graduated Approach– Day 2

15. Option 4 - Graduated Approach– Day 3

16. Option 4 - Graduated Approach– Day 19

17. Option 4 - Graduated Approach– Day 20

18. Option 4 - Graduated Approach Example • At the end of the migration timeline, the transition to the new profile models is complete.

19. Option 2 - Consumption Start Date Cutover • Another option to mitigate the significant change in energy being assigned to the Business High Load Factor class is to use a Consumption Start Date Cutover approach

20. Option 2 - Consumption Start Date Cutover Defined • Readings that have a start date which are on or after the implementation date for the new profile models have their scaling factors calculated based on the new profile models • The rest of the readings are scaled using the old profile models

21. Option 2 - Consumption Start Date Cutover Defined • Requires new shadow settlement logic that determines the meter reading data which is available and what load profile to use in the usage scaling factor calculation • Requires both the old profiles and the new profiles to exist for at least 90 days • Each trade day will have usage profiled using both the new and old profile models

22. MAY 1 Option 2 - Consumption Start Date Cutover Example Meter Read / Trade Day Cases Profile Used 1. Meter rd before transition, trade date w/in read, and before transition 2. Meter rd crosses transition, trade date before transition and w/in read 3. Meter rd crosses transition, trade date after transition and within read 4. Meter rd after transition, trade date after transition and within read 5. Meter rd before transition, trade date before transition, but after read 6. Meter rd before transition, trade date after transition and after read 7. Meter rd crosses transition, trade date after transition and after read 8. Meter read after transition, trade date after transition, and after read Old Profile Old Profile Old Profile New Profile Old Profile Old Profile Old Profile New Profile

23. Option 4 - Trade Day Cutover • Another option to mitigate the significant change in energy being assigned to the Business High Load Factor class is to use a Trade Day Cutover approach

24. Option 4 - Trade Day Cutover Defined • Trade Days before the new profile model implementation date have their scaling factors based on the old profiles • Trade Days on or after the new profile model implementation date have their scaling factors based on the new profiles

25. Option 4 - Trade Day Cutover • Requires new shadow settlement logic that determines what load profile to use in the usage scaling factor calculation based on the trade day being settled • Requires both the old profiles and the new profiles to exist for at least 90 days

26. MAY 1 Option 4 - Trade Day Cutover Example Meter Read / Trade Day Cases Profile Used 1. Meter rd before transition, trade date w/in read, and before transition 2. Meter rd crosses transition, trade date before transition and w/in read 3. Meter rd crosses transition, trade date after transition and within read 4. Meter rd after transition, trade date after transition and within read 5. Meter rd before transition, trade date before transition, but after read 6. Meter rd before transition, trade date after transition and after read 7. Meter rd crosses transition, trade date after transition and after read 8. Meter read after transition, trade date after transition, and after read Old Profile Old Profile New Profile New Profile Old Profile New Profile New Profile New Profile