1. December 18, 2007 TPTF Early Delivery Systems Status Daryl Cote

2. 2 2 TPTF12/17/2007 EDS Status Update 2007 2008 SCED R5.1SCED R5.3: RT ICCPSCED R5.4: LMP Post SepOctNovDecJan Feb SCED R5.2 ICCP Fail-over / P2P R3: SE / Telemetry Criteria (SE Tuning) R4: NOMCR / Network Model verification E1 R2 E2 R3 E2 R4 E3 R5 E3 R6 LFC R6.1: ACE E3 R7 CRR R7.1 E4 R9 R9 6-month LMP Posting SE Verification RT ICCP NOMCR Checkout Network Model Verification EDS 1 Exit Criteria % of MPs % of Points Comments MPs have completed PtP checkout and topology review for all submitted Nodal points (MP5) 95% (95%) 99% (99%) XTend having link problems, RCEC completed 1st phase.  Adding Magic Valley (Q1 ‘08) and College Station (Jan ’08) – approximately 1000 points. ERCOT has completed local failover testing with each MP (MP6)87% (84%) n/a  Tenaska, AEP QSE in 12/07, BTU and Xtend in 01/08. ERCOT has completed Alarm Processing Configuration and testing n/a10%  Alarm processing testing will be phased by category and systems availability. ERCOT has completed all PtP process documentation to support checkout for new construction / future changes to telemetry 95%n/a  Final process handoff and transition to Operations will occur by year end. Outstanding ICCP issues <= 3% per MP (MP5)100% (80%) n/a  Overall error rate ~1%.  9 MPs are at a 0% error rate.  15 MPs tested are at or below 1% error rate. Quality Code Retesting (MP5)100% (92%) n/a  36 of 36 MPs regression tested with quality code fix. Reporting Legend: % in parentheses are from the 11/26 TPTF update

3. 3 3 TPTF12/17/2007 Alarm Processing Approach – Expected Delivery Schedule Implementation EDS 1 by 12/15 EDS 2 by 1/15 EDS 3 by 2/15 MPs OnCor CenterPoint Reliant Luminant Participants will perform limit testing and work with ERCOT to verify procedures.

4. 4 4 TPTF12/17/2007 R4: NOMCR / Network Model verification Release 3 – State Estimator and Telemetry 2007 2008 SCED R5.1SCED R5.3: RT ICCPSCED R5.4: LMP Post SepOctNovDecJan Feb SCED R5.2 ICCP Fail-over / P2P R3: SE / Telemetry Criteria (SE Tuning) E1 R2 E2 R3 E2 R4 E3 R5 E3 R6 LFC R6.1: ACE E3 R7 CRR R7.1 E4 R9 R9 6-month LMP Posting SE Verification RT ICCP NOMCR Checkout Network Model Verification EDS 2 Release 3 Exit Criteria % Complete Comments TSP/QSE data points reasonably conform to Telemetry Performance criteria 40%  SCADA Mappings for Generation in progress – see next slide  324 unobservable points (communicated to TSPs) + ~170 loads to be mapped by ERCOT; polarity correction with one TSP  Quality of MW and GMW provided by QSEs remains at ~40% ERCOT Operations have operating procedures in place to address performance issues 30% (30%) 8 of 27 procedures have been updated. The remaining will be completed when Release 3 processes are verified. Network Security Analysis functions are verified and ERCOT Operations have procedures in place to manage 76% (76%) SE STAT is 95% tested; Contingency Analysis is 95% tested; Dynamic Ratings is 30% tested; RTMONI is 90% tested. ERCOT SE is tuned and meets performance criteria50% (9%) See detailed slide for SE Convergence rates over time. MW/MVar tolerance is 50, SE convergence varies. Load Modeling restructured, load adaptation and bus load forecast verified 50% (25%)  Schedules have been successfully load and have been verified.  Load Adaptation cannot be tested until a bug is fixed. EDW reports correctly post to MIS and can be accessed0%SE and Performance Report Schedule is being re-planned. EDW reports have been verified within ERCOT and by MPs0%Telemetry and State Estimator standards in stakeholder process. Reporting Legend: % in parentheses are from the 11/26 TPTF update

5. 5 5 TPTF12/17/2007 EDS 2 – Generation Verification Status Verifying the following:  Breaker Status  Combine-cycle Configuration  High Emergency Limit  High Sustained Limit  Low Emergency Limit  Low Sustained Limit  Plant Auxiliary Load  Resource Status ‘Complete’ indicates ERCOT mapping is complete and does not reflect data quality

6. 6 6 TPTF12/17/2007 Release 3 – State Estimator Convergence Rate Status No Convergence due to System Problems

7. 7 7 TPTF12/17/2007 EDS 2 – State Estimator and Telemetry Criteria Telemetry CriteriaStatusComment Data Quality (MW/MVar Tolerance) At 50Standard is 15 MV/MVar Telemetry Availability tbdNeed EDW Report Critically Important Telemetry tbdNeed EDS Report Availability for Critically Important Telemetry tbdNeed EDW Report Requests for Redundant Telemetry tbdNeed Critical Measurement functionality State Estimator CriteriaStatusComment SE Convergence Stable at 50MW variance when application is running (e.g. not down due to hardware or database loads) Transmission Element SE Accuracy tbdNeed EDW Report Critical Transmission Element SE Accuracy tbdNeed EDW Report Critical Bus Voltage Accuracy tbdNeed EDW Report SCADA Measurement Accuracy tbdNeed EDW Report Status of SE and Telemetry Criteria

8. 8 8 TPTF12/17/2007 Observability Status Status as of 12/14

9. 9 9 TPTF12/17/2007 Release 4 – NMMS / NOMCR 2007 2008 SCED R5.1SCED R5.3: RT ICCPSCED R5.4: LMP Post SepOctNovDecJan Feb SCED R5.2 ICCP Fail-over / P2P R3: SE / Telemetry Criteria (SE Tuning) R4: NOMCR / Network Model verification E1 R2 E2 R3 E2 R4 E3 R5 E3 R6 LFC R6.1: ACE E3 R7 CRR R7.1 R9 6-month LMP Posting SE Verification RT ICCP NOMCR Checkout Network Model Verification EDS 2 Release 4 Entry Criteria % Complete Comments NMMS Phase 2A has completed FAT Testing0%Planned release of NMMS 2A on January 2, 2008 MIS/NMMS link has completed ITest and is installed in EDS47% (25%)  9 of 17 TSPs have successfully connected through Citrix to notepad (not all the way to NMMS) NMMS is installed in EDS0%Hardware build in progress EMS Nodal Importer has completed ITest and is installed in EDS0%EMS 4 FAT end scheduled for 2/15; will not migrate to EDS until MMS importer also available NMMS database has been successfully loaded with: ERCOT NOM database; ICCP modeling point database; Ownership / operatorship data 0%Currently working with TSPs/MPs (and ERCOT working groups) on data information for loading. Waiting on NMMS 2A delivery to install and configure data NMMS database is placed under full change control0%Once data is loaded and verified by MPs, DB will be under ERCOT change control. Reporting Any direct communication with John Hall or John Webb should be sent to EDS2@ercot.com effective immediately EDS2@ercot.com Legend: % in parentheses are from the last update

10. 10 TPTF12/17/2007 Release 5 - SCED 2007 2008 SCED R5.1SCED R5.3: RT ICCPSCED R5.4: LMP Post SepOctNovDecJan Feb SCED R5.2 ICCP Fail-over / P2P R3: SE / Telemetry Criteria (SE Tuning) R4: NOMCR / Network Model verification E1 R2 E2 R3 E2 R4 E3 R5 E3 R6 LFC R6.1: ACE E3 R7 CRR R7.1 E4 R9 R9 6-month LMP Posting SE Verification RT ICCP NOMCR Checkout Network Model Verification EDS 3 Release 5 Exit Criteria % Complete Comments QSEs w/ Resources able to submit COP & TPO for entire portfolio 100%Known issues with Output Schedules and Performance issues (root cause analysis done on performance issues and passed to teams) SCED Inputs verified: HRL, LRL, SURAMP, SDRAMP, HDL, LDL; GTBD, ICCP 40% (40%) See next slide SCED Outputs verified: QSE’s ability to receive Resource Base Points and LMPs via ICCP 10% (10%) Verifications began November 1 st. A number of QSEs have reported receiving Base Points and LMPs – ERCOT reviewing SCADA mapping. Base Point and LMP calculation verified for Resources with Offer Curves or Output Schedules 0%Verifications to begin in January. Reports50% (0%) Reports related to SCED are available in draft form on MIS and nodal.ercot.com LMPs verified for Reasonability and posted to MIS for Market Participant review0% See next slide Reporting Legend: % in parentheses are from the 10/22 TPTF update

11. 11 TPTF12/17/2007 SCED Issues 1.EMS Hardware insufficient for user base and functionality –INF prioritized production hardware for EMS – will use for EMS 3B 2.SCADA mapping resulted in all Combined Cycles MW telemetry levels set to 0 –Corrected in SCADA load on Friday 12/14; still needs to be verified 3.Interface table for Constraint Names incorrect so SCED is not able to process constraint names & shift factors 4.MPs sending Incorrect values for CC configuration causes SCED failure –Working with EMS team to implement data check and MPs to send valid configuration values 5.MPs sending HSL < LSL resulting in SCED failure –Working with MPs to resolve and adding validation in EMS to set LSL = HSL when telemeter HSL<LSL 6.MPs sending resource status of off when actual telemeter MW output is > 0 –SCED sets basepoint = 0 7.MPs sending invalid resource status (e.g. 050) –SCED ignores the unit 8.DC TIE Telemetry missing and DC Tie calculation not working –Adding telemetry and EMS team resolving calculation function Joint effort between ERCOT and MPs to resolve most of these will enable reasonableness declaration

12. 12 TPTF12/17/2007 Release 6 - LFC 2007 2008 R5.3SCED R5.4: LMP Post JanFebMarAprMay Jun R4: NOMCR / Network Model verification E2 R4 E3 R5 E3 R6 R6.1: ACE E3 R7 R7.1 E4 R9 6-month LMP Posting EDS 3 Release 6.1 Entry Criteria % Complete Comments ICCP and the Generation Subsystem (LFC, RLC and Resource Qualification Testing) has passed FAT and completed acceptable portions of the ITEST. 0%EMS 3B FAT expected to complete 12/21 (revised from 12/7) ERCOT has validated that the RLC outputs and Emergency Base Point calculator values are calculated in the ERCOT Nodal system as expected per the Nodal EMS Design documents. 0%Same as above QSEs with Resources have submitted the 6.1 test form to ERCOT 0%ERCOT expects to distribute the form on January 2. QSEs complete the form and send it back to ERCOT 2 business days before their scheduled 6.1 testing date. Legend: % in parentheses are from the 10/22 TPTF update R6.2: QSE TestingR6.3: TST R7.2R7.3R7.4 Any direct correspondence with Brain Davison should be directed to EDS3@ercot.com effective immediately EDS3@ercot.com

13. 13 TPTF12/17/2007 EDS 3 – LFC Testing Schedule

14. 14 TPTF12/17/2007 EDS 3 – LFC Testing Schedule

15. 15 TPTF12/17/2007 Release 7 - CRR Kick-off meeting scheduled for January 18 th from 1-3pm –http://www.ercot.com/calendar/2008/01/20080118-EDS3.htmlhttp://www.ercot.com/calendar/2008/01/20080118-EDS3.html Working on 7.0 activities –Discrepancies between CRR Account Holder forms and emails to eds3 indicating intention to participate See next slide Planning to present an updated version of CRR handbook to TPTF at the January 21-23 rd meeting. Updated version available at http://nodal.ercot.com/docs/pd/eds/index.html#othhttp://nodal.ercot.com/docs/pd/eds/index.html#oth

16. 16 TPTF12/17/2007 Release 7 - Participants

17. 17 TPTF12/17/2007 EDS 4 – Release 9.1 MMS, EIP, and INT teams working aggressively to support a January 15 th start of Release 9.1 –Will schedule support calls similar to SCED –Might have to start with QSEs desiring to use Web Services first if ERCOT developed UI not available by January 15 th Scheduled a Release 9.1 kick-off WebEx for Thursday 12/20 from 9-11 am: http://www.ercot.com/calendar/2007/12/20071220- EDS4.htmlhttp://www.ercot.com/calendar/2007/12/20071220- EDS4.html Significant number of QSEs have missed deadline to submitted intent emails to EDS4@ercot.com.EDS4@ercot.com –See next slide

18. 18 TPTF12/17/2007 EDS 4 Release 9 QSEs expected for EDS4, but not yet registered –Affordable Power Plan –Alcoa Power Marketing –Alliance Power Company –Ambit Energy –Ambridge Energy –Amigo Energy –Andeler Corporation –APN Starfirst –APNA Holding –Aquila –Barclays Bank –Bear Energy –Blu Power of Texas –Brilliant Energy –Cargill Power Markets –Citadel Energy Products –Clearview Electric –ConocoPhillips Company –Constellation NewEnergy –DPI Energy –Duke Energy Ohio –Eagle Energy Partners –Econnergy Energy Company –Electric Now –First Choice Power –Formosa Utility Venture –Freedom Power –Fulcrum Power Service –Glacial Energy –Himalaya Power

19. 19 TPTF12/17/2007 EDS4 Release 9 QSEs expected for EDS4, but not yet registered (continued) –Integrys Energy Services –JP Morgan Ventures Energy Corporation –Just Energy Texas –Kansas City Power and Light –Keystone Energy Partners –Lehman Brothers Commodity Services –Liberty Power –Merrill Lynch Commodities –Mirant Energy Trading –National Power Company –North American Energy Credit and Clearing Delivery –NRG –ONPAC Energy –PEPCO Energy Services –Pre Buy Electric –Repower –Scurry County Wind –Sitara Energy –Spark Energy –Stream Gas and Electric –Tara Energy –Texas Retail Energy –Texas Star Energy –Texpo Energy –Topaz Power Management –Trieagle Energy Supply –Urban Energy Source –Viasyn –WCW International –Xtend Energy

20. 20 TPTF12/17/2007 Questions?