1. http://nodal.ercot.com 1 Cutover Daily Call 10:30 AM November 23, 2010 10:30

2. http://nodal.ercot.com 2 Antitrust Admonition ANTITRUST ADMONITION ERCOT strictly prohibits Market Participants and their employees who are participating in ERCOT activities from using their participation in ERCOT activities as a forum for engaging in practices or communications that violate the antitrust laws. The ERCOT Board has approved guidelines for members of ERCOT Committees, Subcommittees and Working Groups to be reviewed and followed by each Market Participant attending ERCOT meetings. If you have not received a copy of these Guidelines, copies are available at the Client Relations desk. Please remember your ongoing obligation to comply with all applicable laws, including the antitrust laws. DISCLAIMER All presentations and materials submitted by Market Participants or any other Entity to ERCOT staff for this meeting are received and posted with the acknowledgement that the information will be considered public in accordance with the ERCOT Websites Content Management Operating Procedure.

3. http://nodal.ercot.com 3 Daily Call – 10:30 8 Days Until Go-Live General Updates / Reminder –ERCOT will remove the Market Trials posting Settlement Points and MP Short Names (as of 10/21/2010) today That was a manual posting available only until the automated posting was available on MIS Settlement Points List and Electrical Buses Mapping information may be found under the MIS Operating Day System Conditions portlet MP short names can be found at Landing Page: http://www.ercot.com/mktparticipants/ Direct Link: List of Market Participants in ERCOT Regionhttp://www.ercot.com/mktparticipants/List of Market Participants in ERCOT Region –FAQ: Why a combined cycle resource was not awarded in the DAM, or why DAM transitioned the combined cycle down to a lower configuration at the end of the day. A: The DAM engine studies a 24 hour period, and must respect the resource constraints within that period. DAM must make sure that a resource is capable of shutdown by the last hour of the day/award, so the last hour awarded to a combined cycle resource will be from a shutdown-capable configuration. If no configuration is offered into the DAM that is capable of being shut down directly (this is a RARF parameter), then DAM will not award the resource at all. Similarly, if no configuration is offered into the DAM that is capable of being started up directly, DAM will not award the resource unless it is initially online at the end of the current day.

4. http://nodal.ercot.com 4 Daily Call – 10:30 8 Days Until Go-Live General Updates / Reminder –Listener URLs ERCOT continues to receive several requests for Listener URL updates ERCOT is asking that all remaining updates to Listener URLs be submitted by EOB tomorrow (11/24/2010) to nodalmarkettransition@ercot.com nodalmarkettransition@ercot.com –Data Access Frequency (Dashboards, Extracts, Reports, etc) All MPs need to review the frequency of which they are downloading / programmatically accessing data from ERCOT systems ERCOT Support Teams are finding several MPs that are accessing reports at an unreasonable frequency For example, some Daily Reports (generated once in a 24-hour period) are being hit 150,000+ times / daily by some QSEs This will assist ERCOT in gauging post Go-Live performance and sizing / scaling of systems going forward to support reasonable data access behavior If there are questions on the frequency of a particular report, MPs can access the ERCOT Market Information List (EMIL), currently posted at: (Under Key Documents): http://nodal.ercot.com/readiness/reports/index.htmlhttp://nodal.ercot.com/readiness/reports/index.html

5. Follow-Up: November Full System Reliability and Market Test Results Generation Resource Energy Deployment Performance (GREDP) Measure of how well resources follow dispatch instructions Non-Wind, Non-DSR Generators and DSR Portfolios must have a GREDP less than 8% or 8 MW for 85% of the intervals in which GREDP was scored Percent of Non-WGRs Generation Resources that Met the Protocol Criteria Average Percent of Total Generation During the Test by Fuel Type All Resources 90.97%NA Resources Providing Regulation 92.31%NA Combined Cycle Resources 87.18%27.30% Coal and Lignite Resources 94.44%41.02% Diesel Resources 100.00%0.03% Gas Steam (Non- Reheat Boiler) Resources 100.00%0.00% Gas Steam (Reheat Boiler) Resources 85.71%0.92% Gas Steam (Supercritical Boiler) Resources NA0.00% Hydro Resources 75.00%0.08% Nuclear Resources 100.00%12.21% Simple Cycle (Greater than 90 MW) Resources 92.31%1.52% Simple Cycle (Less than 90 MW) Resources 88.89%0.75% Percent of DSR Portfolios that Met the Protocol Criteria All DSRs0.00% DSRs Providing Regulation NA Non-WGRs/ Non-DSRs DSRs

6. Follow-Up: November Full System Reliability and Market Test Results Generation Resource Energy Deployment Performance (GREDP) Measure of how well resources follow dispatch instructions Wind Generators must have a GREDP less than 10% or the output must be less than their expected output for 95% of the intervals in which GREDP was scored Wind Generators are only scored during curtailment Percent of WGRs that Met the Protocol Criteria 20.51% Number of WGRs that had an Interval for which GREDP was scored 39 Average Percent of Total Generation During the Test from WGRs 16.16% WGRs

7. Follow-UP: Example - Scoring GREDP for IRRs For this example, assume no exclusions were active and that LSL = AEGR = ARI = 0 for the WGR Interval Ending QSERes. Fuel Type Res. Status ATGABP SCED HSL SCED BP ATG – Expected MW GREDP (%) Was Interval Passed? Number of Intervals Scored Percent of Intervals Passed 13:05:00QABCUNIT1WINDON123.5120.5125. 850% 13:10:00QABCUNIT1WINDON131.127.130.129. 13:15:00QABCUNIT1WINDON125.109.5135.90.15.514.155N 13:20:00QABCUNIT1WINDON100.90.135901011.111N 13:25:00QABCUNIT1WINDON95.90.130.90.55.5556Y 13:30:00QABCUNIT1WINDON70.65.125.40.57.6923Y 13:35:00QABCUNIT1WINDON35.40.125.40.-512.5Y 13:40:00QABCUNIT1WINDON25.20.1300525N 13:45:00QABCUNIT1WINDON10.0.1350.10N 13:50:00QABCUNIT1WINDON00.135.0.00Y Wind must have a GREDP less than 10%: GREDP (%) = ABS[((ATG – AEGR)/(ABP + ARI)) – 1.0]*100 ATG <= Expected MW = AEGR + ABP + ARI OR output must be less than expected output: # of Intervals passed: 4 (4÷8)*100 = 50%

8. http://nodal.ercot.com 8 QUESTIONS?