1. http://nodal.ercot.com 1 Market Trials Real Time Market / LFC Weekly Update March 19, 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 –Support Metrics and FAQ –General reminders / updates –Scorecard Update –Qualification update –Special Topic: Web Services Update –Phase 3 RTM / LFC Update –Telemetry Outreach Update –State Estimator Convergence Update –Phase 3 RTM / LFC 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 –Weekend Upgrade: ERCOT is performing system maintenance this coming weekend and early next week in preparation for Market Trials Phase 4. –Real-Time Market- offline for software updates Friday, March 19, 6pm to midnight (no SCED or Real-Time LMPs) –Inbound Web Services- offline Friday March 19, 6pm to midnight –Outage Scheduler and CRR Market are not supported on weekends and will be offline Friday 6pm-Monday 8am. –Outbound Web Services Notifications- will be offline for two maintenance windows (impacts MMS and Outage Scheduler notifications): »Friday March 19, 6pm to Sunday March 21, 8am »Monday March 22, 6pm to Tuesday, March 23, 6pm As part of the weekend maintenance, the External Web Services will be upgraded to be compliant with v1.19i Unplanned Outages –03/16/10 – 03/16/10 09:00 A.M – 09.30 A.M Market Manager system availability was affected as a result of system performance issues. –03/17/10 – 03/18/10 1:30 P.M – 02.30 P.M Trade confirmation notifications failed to deliver during the report period. Issues persist for a few QSEs, and ERCOT is working to address the issue.

6. http://nodal.ercot.com 6 Environment Report: Known Issues ERCOT has identified an issue with posting LMP reports to the MIS when MMS is undergoing backup procedures. As a result, some LMP reports are experiencing delays in posting. ERCOT is working to resolve this environment issue.

7. http://nodal.ercot.com 7 Support Metrics * This week, 3 out of 138 questions were responded to outside of the 24 hour time frame. Market Participant Inbound Questions Last WeekThis Week

8. http://nodal.ercot.com 8 Standing Reports and Updates: General reminders / updates Network Model Update –Current system loaded from the model 3/17/10 –Next scheduled load is 3/31/2010 Verifiable Costs –ERCOT has verified/approved VC for 4 Resources 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/

9. http://nodal.ercot.com 9 Standing reports and updates: General Reminders / Updates Reminder of Phase 4 Kick-Off Call next Thursday –Thursday, March 25, 9am-3pm, Austin Airport Hilton –http://www.ercot.com/calendar/2010/03/20100325-MThttp://www.ercot.com/calendar/2010/03/20100325-MT –WebEx available 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

10. MP15-A Real-Time Market Participation Nodal Scorecard Reminder  3/10 – 3/17 Window – 3 QSEs with Resources regressed below the 95% weekly average for submitting TPOs and/or Output Schedules  Scorecard Calls – Starting 3/22/2010 ERCOT Account Managers will be notifying QSEs with Resources if their submissions have slipped  Scorecard Post Date – The next AMBER/RED scores will post on 4/7/2010  Red, Amber, Green Rules  Red - < 85% weekly average for submissions  Amber - >= 85% and < 95% weekly average for submissions  Green - >= 95% weekly average for submissions Visit the Nodal Readiness Scorecard at http://scorecard.ercot.com/http://scorecard.ercot.com/ http://nodal.ercot.com 10

11. http://nodal.ercot.com 11 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 –177 QUALIFIED –17 QSEs without Resources remain to be qualified

12. http://nodal.ercot.com 12 Special Topic Web Services Update for Nodal Market Trials Real Time Market / LFC Market Call March 19, 2010

13. http://nodal.ercot.com 13 Web Services Update Will be posted early next week Next NPROD release – Phase 5 Scope (these items previously announced as future changes): Change- Ancillary Service values –Change from “Float” to “Decimal” values to avoid scientific notation (eg, 1.6E01) Change - Cancel Outage API with ability to include notes –The existing “cancel OutageSet” API will be extended to allow the market participant to include RequestorNotes, SupportingNotes, and RASPSNotes in the request Payload. These elements will not be required. –The API will still support “cancel OutageSet” without notes. –The Market Manager UI will also support with and without notes. New - Get Notifications API –This will be a new API available to the market but not required for consumption. It will provide a market participant with the ability to query for Bid, Resource Parameter, and VDI acceptance and rejection notifications. –The API will support such features as querying by MRID, by time range, and by status (acceptance / rejection). The API will be constrained to a minimal amount of historical data availability. –The API / feature set will be available via the machine-to-machine API and Market Manager UI. Change - Startup / Shutdown Instructions Schema –Today, the hour ending is defined as an integer. This must be changed to string to allow the API to better represent DST (repeating hours using the * convention found elsewhere in the API for DST). EIS Specifications 1.19k

14. http://nodal.ercot.com 14 Web Services Update Scope (new): Confirmed/Unconfirmed Trades –Update example for mRID structure Opportunity Outages –Add new element takeOpportunity to OutageUpdate Dynamic Ratings API –Change deliveryTime to deliveryDate Three Part Offer –Clarify that curveStyle is not a valid element EIS Specifications 1.19k

15. 3/5/2016 http://nodal.ercot.com 15 Real Time Market / LFC Update

16. http://nodal.ercot.com 16 SCED Week 7  LMPs mostly in the $20 to $50 range  Hit $2250 Monday – under investigation; will include follow up information on next Friday Real-Time Market Call ERCOT LOAD LMP

17. http://nodal.ercot.com 17 Real Time Market / LFC Update Upcoming LFC QSE Tests QSE LFC Tests scheduled next week (March 22-26): NEXTERA (SQ1, SQ2, SQ3, SQ4) FULCRUM QSE DIRECT ENERGY QSE LCRA CPS ENERGY LUMINANT SQ1 & SQ2 TENASKA / TRQ4 / TRQ7 AEP (SQ3 & OKLAUNION) STEC (QSE & SQ2)

18. http://nodal.ercot.com 18 Real Time Market / LFC Update LFC Calendar Status 76 QSEs/Sub-QSEs are currently targeted for Individual QSE tests 62 have scheduled a test window (93.43% of Generation) 10 QSE/Sub-QSEs have completed testing (58.42% of Generation): NRG TEXAS / NRG SQ1 OPTIM ENERGY/OPTIM ENERGY SQ1 CALPINE FORMOSA CPS ENERGY / CPS ENERGY SQ1 LUMINANT EAGLE QSE The updated LFC Calendar was posted to the Readiness Center MAR 18 http://nodal.ercot.com/readiness/markettrials/rtm/index.html http://nodal.ercot.com/readiness/markettrials/rtm/index.html

19. 3/5/2016 http://nodal.ercot.com 19 Nodal Telemetry Outreach (NTO) Update and State Estimator Convergence

20. http://nodal.ercot.com 20 Telemetry Outreach QSE Telemetry 1 point required for State Estimator still missing (~99% complete for nodal telemetry) 8 points required for SCED execution still missing (~99% complete for nodal telemetry) TSP Telemetry ERCOT is working with TSPs to resolve remaining telemetry issues in time to support Market Trials Phase 5.0 Currently working on model cleanups and ownership issues Progress in TSP telemetry will continue to be reported to NDSWG The TSP Telemetry Dashboard is scheduled to refresh to the Readiness Center March 25, http://nodal.ercot.com/readiness/markettrials/rtm/index.htmlhttp://nodal.ercot.com/readiness/markettrials/rtm/index.html

21. http://nodal.ercot.com 21 State Estimator Convergence State Estimator Daily Convergence Statistics (these percentages are graphed in the next slide) MonthDay% Convergence (Including Solved w/ Mismatch) MAR1798.26 MAR1697.92 MAR1598.60 MAR14100 MAR1399.65 MAR1298.97 MAR1198.96 MAR10100 MAR997.27 MAR899.31

22. http://nodal.ercot.com 22 State Estimator Convergence

23. http://nodal.ercot.com 23 Q&A Q&A / Open Forum

24. http://nodal.ercot.com 24 Appendix

25. http://nodal.ercot.com 25 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)

26. http://nodal.ercot.com 26 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

27. http://nodal.ercot.com 27 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