1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS 3 Release 5 Monday / Friday Market Updates Feb 01, 2008

2. Lead from the front Texas Nodal http://nodal.ercot.com 2 Agenda Antitrust Admonition Submissions Update –This Week’s Activities –Submissions Status LMP Reasonableness Updates / Questions / Reminders LFC Update Q&A / Open Forum Roll Call

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 Times for 02/04/08 Activities for Week of 02/04/08 –Submit the following during the 12:00 – 4:00pm submission window: COP for trade date +2 TPO for trade date +2 Output Schedule (open to all resources) INC/DEC (DSR resources only) –Submit RT COP adjustments during business hours –Submit RT OS adjustments during business hours

5. Lead from the front Texas Nodal http://nodal.ercot.com 5 1/21/20081/22/20081/23/20081/24/20081/25/2008 75%52% 79%48% 88%66% 86%62% 88%74% COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS 1/30/20081/31/20082/1/2008 92%85% 89%87% 82%89% COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS 1/26/20081/27/20081/28/20081/29/2008 89%81% 89%79% 58%72% 90%79% COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS

6. Lead from the front Texas Nodal http://nodal.ercot.com 6 LMP Reasonableness – System Stability Metrics Critical measurement regression test caused system to crash every 4 th run (10:00 through 17:00) Inbound telemetry issue (invalid CC configuration) caused SCED to fail 1/29 daily average: 97.6%; 1/30 daily average: 92%

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 LMP Reasonableness – 345 KV Hubs – Nodal TEST data Number of intervals with prices over $100 increased substantially from previous day..

8. Lead from the front Texas Nodal http://nodal.ercot.com 8 LMP Reasonableness - SCED Input Data Issues (number of units with issues)  Type 1:Telemeter incorrect status (Actual MW output>0 & Status = Off)  Type 2: no TPO (Status = one of the 'ON' statuses)  Type 3: Telemeter outside limit (Net Telemetered MW value outside HSL or LSL)

9. Lead from the front Texas Nodal http://nodal.ercot.com 9 LMP Reasonableness Outstanding Issues (ERCOT) –Discovered issue where valid base points are not being telemetered –Data inconsistencies between EMS and MMS Outstanding Issues (QSE’s) –Telemetry Input – Still working with QSE’s –Consistent Daily Market Submissions (TPO, COP, etc) –TPO Expiration Time needs to be the end of the day –No Live Telemetry Data from a Subset of QSE’s (required since Nov.)

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 Updates / Questions / Reminders –Update: MIS / MM UI – Fix to previous build deployed this week (market notice sent Wed) Known issues posted to readiness center: http://nodal.ercot.com/readiness/eds4/documents/index.html http://nodal.ercot.com/readiness/eds4/documents/index.html SCED Interfaces –Will be delayed (not Friday as previously communicated) –Continue to use EDS 3.5 UI for SCED Input Issue reporting and feedback uses same process as EDS 3 –RARF Updates Start Submitting to 12/31 RARFs Updates were made w/o notice as most RARF’s expanded LRL / HRL For NEW resources and additional CC Configurations – these are not yet in –Sandbox and Reports Outage Outage will be general maintenance Starts Friday 2/1 4:00 PM || Ends Sunday 2/3 Evening –External Interface Specifications v1.07 has been released to sandbox (see next slide for new transactions).

11. Lead from the front Texas Nodal http://nodal.ercot.com 11 Updates / Questions / Reminders New features added to sandbox with v1.07 release: –Create OutageSet (Market Transactions, verb-create, noun-OutageSet) –Get OutageSet (MarketInfo, will always return a pre-formed XML, verb-get, noun- OutageSet) –Create a TestNotification (MarketTx, verb-create, noun-TestNotification) –change ActiveNotificationURL (MarketTx, verb-change, noun-ActiveNotificationURL) –Generate daily notifications to all the registered MPs for the following (pre-formed XMLs) –ASObligations –AwardedAS –AwardedCRR –AwardedEnergyBid –AwardedEnergyOffer –AwardedEnergyOnlyOffer –AwardedPTPObligation –ConfirmedTrades –UnConfirmedTrades –OutageSet –StartupShutdownInstructions –Get AwardSet

12. Lead from the front Texas Nodal http://nodal.ercot.com 12 LFC Update Testing Progress –Companies which tested this week: STEC BP Energy Suez Energy Austin Energy Exelon –ERCOT Issues Encountered: Emergency Base Point Validation –ERCOT issues have prevented any test completions. (Updates being made to correct) Once the fixes are in place, companies will be contacted to complete the RLC (If applicable) & Emergency base point validation. Test Form revisions will be posted to the readiness center as necessary. Test Form submissions are to be submitted two business days before the test. All submissions should be sent to EDS3@ercot.com.EDS3@ercot.com The QSE list for Testing next week is: –Tuesday 9:00 AM – Constellation

13. Lead from the front Texas Nodal http://nodal.ercot.com 13 Q&A Q&A / Open Forum