1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS 3 Release 5 and 6 Friday Market Updates Dec 19, 2008

2. Lead from the front Texas Nodal http://nodal.ercot.com 2 Agenda Antitrust Admonition SCED Update –Submission Metrics Update –Updates / Questions / Reminders LFC / State Estimator Update Q&A / Open Forum Roll Call API Subgroup Topics

3. Lead from the front Texas Nodal http://nodal.ercot.com 3 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.

4. Lead from the front Texas Nodal http://nodal.ercot.com 4 Submission Metrics Update 12/13/200812/14/200812/15/200812/16/2008 (FIT) N/A69%8N/A69%10N/A69%10N/A91%15 COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS 12/17/2008 (FIT)12/18/2008 (FIT)12/19/2008 N/A92%12N/A94%32N/A84%34 COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS SEE EDS PROGRAM UPDATE FOR NEW SUBMISSION REQUIREMENTS

5. Lead from the front Texas Nodal http://nodal.ercot.com 5 Updates / Questions / Reminders Unplanned Environment Outages –12/15 4:00pm – 4:10pm – MMS Services Stalled – Known Issue –12/15 8:00am – 2:25pm – Notification messages (Sandbox and EDS) (ERCOT  QSE) were malformed. Result of maintenance patch performed on Saturday to resolve Go Daddy CA Issue. Patch was backed out to resolve issue UPDATE: EDS Program Update –COMPLETE: Preliminary nodal integrated schedule released –COMPLETE: TAC initial review 12/4/08 –COMPLETE: TPTF initial review 12/10/08 3:30-5:30pm (WebEx) Materials: http://www.ercot.com/calendar/2008/12/20081210-TPTFNOD http://www.ercot.com/calendar/2008/12/20081210-TPTFNOD –COMPLETE:TPTF detailed discussion on 12/16 Materials: http://www.ercot.com/calendar/2008/12/20081215-TPTFhttp://www.ercot.com/calendar/2008/12/20081215-TPTF

6. Lead from the front Texas Nodal http://nodal.ercot.com 6 Updates / Questions / Reminders UPDATE: EDS Program Update (continued…) –Summary of 12/16 Discussion with TPTF Questions sent in by MP’s were addressed and discussed The EDS Activities Reviewed It was decided that further discussions were required –There will be a dedicated workshop on 1/7/09 –Further consideration will occur at subsequent TPTF meetings Current decisions for market activities: –MP Telemetry will remain active at all times, with issue resolution occurring during business hours only –FIT testing will continue into Jan. –SCED submissions will cease (both, daily and during FIT testing windows) until additional review of the value add is completed in Jan. »MP15a will be suspended during this time –EDS Market Calls / API Subgroup will continue through Jan ’09 and be revisited after further discussions with TPTF »Next EDS Market call to occur on 1/9/09

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 Focused SE & SCED Testing Next testing will take place 1/13 – 1/15 Reminder: the January FIT windows have been reduced to 3x9 windows FIT II Assessment reports will be posted at: http://nodal.ercot.com/readiness/eds3/documents/index.html http://nodal.ercot.com/readiness/eds3/documents/index.html ALL TIMES ARE CENTRAL DurationStart date and timeEnd date and time 27 hrs (3x9) January 13 - 8:00 amJanuary 15 - 5:00 pm 27 hrs (3x9) January 27 - 8:00 amJanuary 29 - 5:00 pm

8. Lead from the front Texas Nodal http://nodal.ercot.com 8 Focused SE & Security Constrained Economic Dispatch Testing (SCED) FIT II Assessment reports will be posted at: http://nodal.ercot.com/readiness/eds3/documents/index.htmlhttp://nodal.ercot.com/readiness/eds3/documents/index.html Key Numbers –96.18% Test Average Convergence –19 of the 27 Test Hours had 100% Convergence

9. Lead from the front Texas Nodal http://nodal.ercot.com 9 Q&A Q&A / Open Forum

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 API Sub-Group General Discussion