1. http://nodal.ercot.com 1 Market Trials Real-Time Market / LFC Weekly Update March 26, 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 Agenda Antitrust Admonition Environment Report –Planned / unplanned outages –Known Issues Standing Reports and Updates –General reminders / updates –Scorecard Update –Qualification update –Phase 3 RTM / LFC Update –LFC Update: Status of Individual QSE Tests for LFC –Telemetry Outreach Update –State Estimator Convergence Update Question and Answers / General Discussion ERCOT asks that Market Participants log into the WebEx session using their company name and then their name. This will allow ERCOT to take roll-call offline

4. Market Trials 2010 Roadmap http://nodal.ercot.com 4

5. http://nodal.ercot.com 5 Environment Report: Planned / Unplanned Nodal Outages Planned Outages –03/22/10 – 03/23/10 06:00 P.M – 06:00 P.M EWS outbound notification service was turned off as a result of scheduled Operating Day test on NPROD environment. Affected availability of notifications generated from EMS/MMS/OS/EWS systems. –03/27/10 – 03/28/10 ERCOT will be performing site to site failover testing this weekend. The testing affects the nodal production environment and may cause SCED to miss some intervals (Market Notice sent 3/24/10). –03/29/10 6:00 P.M. – 03/30/10 6:00 P.M. EWS outbound notification service will be turned off in support of a scheduled Operating Day test in the NPROD environment. Unplanned Outages –03/22/10 – 03/22/10 09:45 A.M – 11.00 A.M Market Manager/Outage Scheduler UI system availability was affected as a result of system performance issues. –03/22/10 – 03/25/10 08:00 A.M – 11.30 P.M External Web Services users were unable to validate “Digital Signature” associated with synchronous responses from Three-Part Offer and Inc/Dec Offer transaction submission.

6. http://nodal.ercot.com 6 Environment Report: Known Issues Real-Time Known Issues List –The Real-Time Known Issues List was updated on the Readiness Center 3/24/2010 (http://nodal.ercot.com/readiness/markettrials/rtm/index.html)http://nodal.ercot.com/readiness/markettrials/rtm/index.html

7. http://nodal.ercot.com 7 Standing Reports and Updates: General Reminders / Updates External Interfaces Specification v1.19k –Posted to the Readiness Center on 3/31/2010 http://nodal.ercot.com/readiness/sandbox/index.html http://nodal.ercot.com/readiness/sandbox/index.html Network Model Update –Current system loaded from the model 3/17/10 –Next scheduled load is 3/31/2010 Reminder of market call schedule: 09:00 AM-10:00 AM Outage Scheduling 10:00 AM-11:00 AM Congestion Revenue Rights 11:00 AM-12:00 PM Day Ahead Market / RUC / SASM 12:00 PM-01:00 PM Break 01:00 PM-02:00 PM Real Time Market / LFC –WebEx Details will be posted at: http://www.ercot.com/committees/nodal/mt/ http://www.ercot.com/committees/nodal/mt/

8. http://nodal.ercot.com 8 Standing Reports and Updates: General Reminders / Updates Reminder of published the Market Trials Phase 4 Handbooks –Outage Scheduler covering Phase 4.0 http://nodal.ercot.com/readiness/markettrials/os/index.htmlhttp://nodal.ercot.com/readiness/markettrials/os/index.html –Real Time Market / LFC covering Phase 4.0 http://nodal.ercot.com/readiness/markettrials/rtm/index.htmlhttp://nodal.ercot.com/readiness/markettrials/rtm/index.html –CRR covering release Phase 4.0 http://nodal.ercot.com/readiness/markettrials/crr/index.htmlhttp://nodal.ercot.com/readiness/markettrials/crr/index.html –Settlements / COMs covering Phase 4.0 http://nodal.ercot.com/readiness/markettrials/coms/index.htmlhttp://nodal.ercot.com/readiness/markettrials/coms/index.html –Day-Ahead Market Phase 4.0 http://nodal.ercot.com/readiness/markettrials/dam/index.htmlhttp://nodal.ercot.com/readiness/markettrials/dam/index.html

9. http://nodal.ercot.com 9 Standing Reports and Updates: Scorecard Update Nodal Readiness Scorecard –The Nodal Readiness Scorecard has been updated (see 03/24/10 Market Notice): Updated MP Metrics –MP3 Market Submissions Connectivity Qualification –MP11 Resource Registration –MP14-C TSP Model Validation –MP20 Outage Scheduler Connectivity Qualification Updated ERCOT Metrics –MO4 Verify SCED Execution Quality –MO5 Generate 6 Months of LMPs New MP Metrics Activated –CRR3 Operations of CRR Auctions and Allocations –The Nodal Readiness Scorecard is available on the Readiness Center at http://nodal.ercot.com/readiness/scorecard/index.html http://nodal.ercot.com/readiness/scorecard/index.html –Scorecard questions may be submitted to nodalscorecard@ercot.comnodalscorecard@ercot.com

10. http://nodal.ercot.com 10 Standing Reports and Updates: Qualification Update QSEs with Resources and Load and Load Only –85 TOTAL –82 QUALIFIED representing 98.97% of the generation –2 QSEs with Resources remain to be qualified (1 is partially qualified) –1 QSE with Load Resources Only remains to be qualified –Note that the total numbers are in flux as QSEs enter and leave the market QSE without Resources –196 TOTAL –179 QUALIFIED –17 QSEs without Resources remain to be qualified

11. 3/20/2016 http://nodal.ercot.com 11 Real Time Market / LFC Update

12. http://nodal.ercot.com 12 SCED Week 8 $2250 on 3/20, 3/21, and 3/22 due to drastic change in weather and load pattern (generation changes) Last week’s $2250 was result of DST testing performed 3/14 (wrongly reported as Monday last week) ERCOT LOADLMP $

13. Real Time Market / LFC Update http://nodal.ercot.com 13 LMP’s were mostly in the $20 - $40 range except for the weekend An OC3 was activated on 3/24 and price separation occurred as expected ZONAL West to North Dynamic Stability constraint was activated 3x last week West to North Dynamic Stability has not yet been modeled in the NODAL system therefore no price separation occurred

14. http://nodal.ercot.com 14 LFC Update: Status of Individual QSE Tests for LFC LFC Calendar Status 76 QSEs/Sub-QSEs are currently targeted for Individual QSE tests 61 have scheduled a test window (93.43% of Generation) 21 QSE/Sub-QSEs have completed testing (71.35% of Generation): The updated LFC Calendar was posted to the Readiness Center MAR 26 http://nodal.ercot.com/readiness/markettrials/rtm/index.html http://nodal.ercot.com/readiness/markettrials/rtm/index.html BRAZOSFORMOSANEXTERA_SQ4 CALPINEFPL_KEIRNRG_SQ1 CPSLCRANRG_TEXAS CPSSQ1LUMINANTOPTIM_ENERGY DIRECTNEXTERA_SQ1OPTIMENERGYSQ1 DIRECTSQ2NEXTERA_SQ2TENASKA EAGLENEXTERA_SQ3TRQ4_SQ4

15. http://nodal.ercot.com 15 LFC Update: Status of Individual QSE Tests for LFC Upcoming LFC QSE Tests Upcoming QSE LFC Tests through April 2: STEC NEXTERA BULLCREEK SWEETWATER WIND5 EC&R (SQ3) TENASKA (TRQ1/TRQ9) PSEG (ODESSA)

16. 3/20/2016 http://nodal.ercot.com 16 Nodal Telemetry Outreach (NTO) Update and State Estimator Convergence

17. http://nodal.ercot.com 17 Telemetry Outreach Update TSP Telemetry ERCOT is working with TSPs to resolve remaining telemetry issues in time to support Market Trials Phase 5.0 ERCOT has used commented point lists provided by TSPs to create a bucket list of ~1500 points that need to be resolved: ERCOT is currently working on model cleanups and ownership issues Progress in TSP telemetry will continue to be reported to NDSWG and on the regularly scheduled Real-Time Market Call The TSP Telemetry Dashboard is posted on the Readiness Center at http://nodal.ercot.com/readiness/markettrials/rtm/index.html http://nodal.ercot.com/readiness/markettrials/rtm/index.html

18. http://nodal.ercot.com 18 State Estimator Convergence Update State Estimator Daily Convergence Statistics (these percentages are graphed in the next slide) MonthDay% Convergence (Including Solved w/ Mismatch) MAR1598.60 MAR1697.92 MAR1798.26 MAR1886.99 MAR1983.86 MAR2099.26 MAR21100 MAR2298.56 MAR2399.65 MAR2499.76

19. http://nodal.ercot.com 19 State Estimator Convergence Update

20. http://nodal.ercot.com 20 Q&A Q&A / Open Forum

21. http://nodal.ercot.com 21 Appendix

22. http://nodal.ercot.com 22 URLS and EMAIL ADDRESS FOR SUPPORT URLs for access the Nodal Production systems –MIS: https://mis.ercot.com/pps/tibco/mis/https://mis.ercot.com/pps/tibco/mis/ –Market Manager: https://mis.ercot.com/pps/tibco/mis/ Click the ‘Applications’ tab in the upper menu. Link is in the ERCOT Applications portlethttps://mis.ercot.com/pps/tibco/mis/ –CRR: https://mis.ercot.com/pps/tibco/mis/ Click the ‘Markets’ Link in the upper menu. Click CRR in the Market sub menuhttps://mis.ercot.com/pps/tibco/mis/ –EWS: https://misapi.ercot.com/2007-08/Nodal/eEDS/EWShttps://misapi.ercot.com/2007-08/Nodal/eEDS/EWS Reminder: Market Trials email address change: ERCOT asks that MPs use the markettrials@ercot.com email address for questions from this point forwardmarkettrials@ercot.com –This will begin the phasing out of eds2@ercot.com, eds3@ercot.com and eds4@ercot.com email addresses.eds2@ercot.comeds3@ercot.com eds4@ercot.com –A centralized address will no longer require MPs to “guess” which email address to use for their questions –We have implemented a more effective method of routing and responding to emails using this address –The old eds emails can continue to be used until 2009 hold over efforts are completed (such as telemetry outreach)

23. http://nodal.ercot.com 23 Market Trials Handbooks –ERCOT will release the following Handbooks In December Real Time Market / LFC covering Phase 3.0 http://nodal.ercot.com/readiness/markettrials/rtm/index.htmlhttp://nodal.ercot.com/readiness/markettrials/rtm/index.html Outage Scheduler covering Phase 3.0 http://nodal.ercot.com/readiness/markettrials/os/index.htmlhttp://nodal.ercot.com/readiness/markettrials/os/index.html CRR covering release Phase 3.0 http://nodal.ercot.com/readiness/markettrials/crr/index.htmlhttp://nodal.ercot.com/readiness/markettrials/crr/index.html Settlements / COMs covering Phase 3.0 http://nodal.ercot.com/readiness/markettrials/coms/index.htmlhttp://nodal.ercot.com/readiness/markettrials/coms/index.html Day Ahead Market (note that this contains only reference data to the 2.1 qualification as there is no Phase 3.0 scope) http://nodal.ercot.com/readiness/markettrials/dam/index.htmlhttp://nodal.ercot.com/readiness/markettrials/dam/index.html –The Phase 4.0 release of the Market Trials Handbooks will occur in early February. –The Phase 5.0 release of the Market Trials Handbooks will occur in March

24. http://nodal.ercot.com 24 Verifiable Cost Submission (originally presented on 4/17) WMS Approved Verifiable Cost Submission Timelines: Simple Cycle Greater than 90MW June 30, 2009 Simple Cycle Less than or Equal to 90MW July 31, 2009 Gas Steam Non-Reheat Boiler Aug 31, 2009 Gas Steam Reheat BoilerSep 30, 2009 Gas Steam Super Critical BoilerOct 31, 2009 Combined Cycle Less than or Equal to 90MW Nov 30, 2009 Combined Cycle Greater than 90MW Dec 31, 2009 Coal, Lignite Jan 31, 2010 Nuclear, Hydro and Renewable Feb 28, 2010 Reciprocating Engines Feb 28, 2010