1. http://nodal.ercot.com 1 Cutover Market Call November 27, 2010

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 General Updates / Reminders

4. http://nodal.ercot.com 4 General Updates and Reminders Network Model Load Dates 11/24/2010 – Completed as scheduled - Last update prior to Go-Live 12/15/2010 The Saturday 4:30 PM Market Call on 11/27/2010 will be canceled –Note that the 10:30 AM call on the same day will take place –Daily calls will resume as scheduled on Sunday 11/28/2010

5. NOVEMBER 2010 SUNDAYMONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAY 123456 78910111213 1415 10:00AM – Market Call 1617 3:00PM – TSP Market Call 1819 9:00AM –Market Call 20 2122 10:00AM – Market Call 23 10:30AM / 4:30PM – Daily Market Call 24 10:30AM / 4:30PM – Daily Market Call 25 ERCOT HOLIDAY 26 ERCOT HOLIDAY 27 10:30AM– Daily Market Call Note that 4:30 PM Market Call canceled for this date 28 10:30AM / 4:30PM – Daily Market Call LFC Market Call 11:00AM – 5:00PM 29 10:30AM / 4:30PM – Daily Market Call *LFC Market Call 30 10:30AM / 4:30PM – Daily Market Call *LFC Market Call * LFC Market Call – Beginning at 6:00AM on 11/29 and continuing through 11:59 PM on 12/1 http://nodal.ercot.com 5

6. DECEMBER 2010 SUNDAYMONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAY * LFC Market Call – Beginning at 6:00AM on 11/29 and continuing through 11:59 PM on 12/1 1 10:30AM / 4:30PM – Daily Market Call *LFC Market Call 2 10:30AM / 4:30PM – Daily Market Call 3 9:00AM –Market Call 4:30PM – Market Call 4 10:30AM / 4:30PM – Daily Market Call 5 10:30AM / 4:30PM – Daily Market Call 6 10:30AM / 4:30PM – Daily Market Call 7 10:30AM / 4:30PM – Daily Market Call 8910 9:00AM –Market Call 11 1213 10:00AM – Market Call 1415 3:00PM – TSP Market Call 1617 9:00AM –Market Call 18 1920 10:00AM – Market Call 212223 ERCOT HOLIDAY 24 ERCOT HOLIDAY 25 2627 10:00AM – Market Call 2829 3:00PM – TSP Market Call 3031 9:00AM –Market Call http://nodal.ercot.com 6

7. Cut-Over Update – Go-Live Sequence of Events DateActionComments 11/15/2010 – 11/29/2010 ERCOT Initiates “Soft Launch” to Nodal Market Go-Live ERCOT will run non-binding DAM, RUC daily per Nodal protocol timelines. RTM will remain Open Loop, but continue to publish base points and LMPs. Note that credit will be set high on 11/15 11/15/2010 Credit posts ACLs and TPEs for non- binding DAM For Operating Day 11/15 credit will be manually set to high limits 11/16/2010First Credit Operating Day 11/16Credit reflects actual limits 11/17/2010 Market now able to submit transactions for first Nodal Operating Day (T-14d) 12/01 Operating Day open for Market submissions 11/24/2010 QSEs with Resources required to submit 7 days of rolling COPs 12/01 required on 11/24 11/28/2010 2:00 PM – 11/28/2010 3:00 PM Generation and Frequency Control switched to Nodal systems for final LFC test QSEs will begin following Nodal base points Settlements will continue to be Zonal 11/28/2010 2:00 PM – 11/30/2010 11:59:59 PM QSEs remain on Nodal Control while settling Zonally during the LFC test 11/29/2010 Last Non- Binding DAM for operating day 11/30 http://nodal.ercot.com 7

8. http://nodal.ercot.com 8 Full-System Test / Nodal Cutover: Communication Items Notices : –A Market Notice confirming the Nov 28, 14:00, start time was sent Nov 23 –A follow-up Market Notice will be sent two days prior to the actual test to confirm the date and start time –An additional Market Notice will be sent on Nov 28 to confirm the start time A hotline call will be made on the day of the test to communicate the start time of the test (approximately 2-3 hours prior to start) An All-QSE VDI will be issued immediately prior to the start of the test –The VDI will be define the “test period” to begin when the first QSE is brought under Nodal control and to end at 23:59:59 CST on Nov 30 Market WebEx: –A Market-facing WebEx will be provided during the following times: Nov 28 – 11:00 to 17:00 (six hours) Nov 29 – 06:00 to 23:59 (all day) Nov 30 – 00:00 to 23:59 (all day) Dec 01 – 00:00 to 23:59 (all day)

9. http://nodal.ercot.com 9 Full-System Test / Nodal Cutover: Timeline DateTimeEvent 11/2811:00Open Market WebEx 11:30Pre-test meeting for Nodal Support Staff 12:00Hotline call by ERCOT Operators to announce the start time Market Notice to be sent out with the cut-over start time Operators to start using OC3s to manage congestion 14:00Hotline call to QSEs/TOs to announce the start of cut-over ERCOT Operators begin switching QSEs to Nodal control 14:45All QSEs switched to Nodal control Hotline call to announce that all QSEs are on Nodal control 17:00Recess Market WebEx 18:00-18:30ERCOT staff transitions from day-side to night-side support 11/2906:00Resume Market WebEx 06:00-06:30ERCOT staff transitions from night-side to day-side support 18:00-18:30ERCOT staff transitions from day-side to night-side support 11/3006:00-06:30ERCOT staff transitions from night-side to day-side support 18:00-18:30ERCOT staff transitions from day-side to night-side support 12/100:00Nodal Market Go-Live/VDI for QSEs to end 06:00-06:30ERCOT staff transitions from night-side to day-side support 18:00-18:30ERCOT staff transitions from day-side to night-side support 23:59End Market WebEx

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