1. http://nodal.ercot.com 1 Cutover Daily Call 4:30 PM November 23, 2010 4:30

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 – 4:30 8 Days Until Go-Live General Updates / Reminder –FAQ: The Zonal data that is not required past 12/1, does this include Zonal Telemetry? A: Zonal telemetry is not required past 12/1. Please note that, as with all Zonal data requirements, ERCOT may extend this need based on Nodal System conditions. This will be communicated via Hotline, Market Call and Market Notice if required. –WGR during EMBP Activation and W2N is active WGRs may receive special instructions to hold their last base point (depending on whether the IROL is active) ERCOT expects that this instruction will come as a hotline call For purposes of calculating GREDP, ERCOT does not consider the 5-minute clock intervals during which Emergency Base Points have been issued (see NP 8.1.1.4.1 (6)(b))

4. FAQ http://nodal.ercot.com 4 Trade confirmation Documentation: Market Submission Validation Rules on the MIS, Day-Ahead market page Market Manager User Guide: http://nodal.ercot.com/readiness/markettrials/connectivity/keydocs/Market_Manager_Use r_Guide_06.doc http://nodal.ercot.com/readiness/markettrials/connectivity/keydocs/Market_Manager_Use r_Guide_06.doc

5. FAQ (cont’d) http://nodal.ercot.com 5 QSEs receive systematic notifications from ERCOT when their counterparty confirms the trade by submitting the matching trade. The timestamp of this notification can be compared to the RUC timestamp to understand whether or not the trade should be included in the snapshot. Notifications can also be queried after the fact via web services or via Market Manager (Notices tab). –A word of caution is that this notification only says that a trade is confirmed between Buyer1 and Seller1 at SettlementPoint1, it doesn’t include the delivery hours or the quantity details. A trade query can be done after the notification is received to confirm the hours/details. Similarly, QSEs can capture the timestamp of the acknowledgement for the trade that is received when they submit the matching trade that confirms the transaction. Note that if the counterparty structures the xml in such a way as to submit each hour separately, a trade confirmation notification will be sent for each hour of the trade. If the xml is structure to submit the trade as a block of time, only one notification will be sent. Example – 24 hour trade. If the counterparty submits each hour separately, you receive 24 identical notifications. If the counterpart submits the trade as hours 1-24 within the xml, you receive 1 notification.

6. http://nodal.ercot.com 6 QUESTIONS?

7. http://nodal.ercot.com 7 Appendix

8. http://nodal.ercot.com 8 Items Covered in 10:30 AM Call

9. http://nodal.ercot.com 9 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.

10. http://nodal.ercot.com 10 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

11. 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

12. 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

13. 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%