1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS Market Call Bi-Weekly Update June 12, 2009

2. Lead from the front Texas Nodal 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. Lead from the front Texas Nodal http://nodal.ercot.com 3 Agenda Anti-trust Admonition Day-to-day operations summary –Planned and Unplanned ERCOT outages of EDS systems –Future dates of any system upgrades Standing reports and updates –General Reminders –Focused Input Testing –Nodal API sub-group Question and Answers/General Discussion Deep Dive Topic (different topics each meeting as needed) –EIS 1.19 Changes 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. Lead from the front Texas Nodal http://nodal.ercot.com 4 Day-to-day operations summary: Planned / Unplanned Outages of EDS Planned Outages –6/14/09 7am – 6/15/09 8am General EDS environment outage for planned Maintenance Unplanned Outages –5/18/09 – Ongoing – Several issues encountered after Maintenance performed on 5/18. Currently reports are available, but will experience brief periods of unavailability. At this time there is not an ETA for the hardware upgrade. –6/9 – 6/10 Wind Forecast reports not publishing. Worked with vendor to resolve.

5. Lead from the front Texas Nodal Standing reports and updates Program Update – Creation of the Nodal Implementation Team (NIT) –At its June 4, 2009 meeting, TAC created the Nodal Implementation Team (NIT) which will be a vehicle for stakeholder engagement in the Nodal program. –In preparation for the NIT initial meeting, the TPTF email distribution list has been discontinued and has been replaced by the NIT distribution list (NIT@lists.ercot.com)NIT@lists.ercot.com If you were previously subscribed to the TPTF distribution list, no action is needed as TPTF subscribers were automatically migrated to the NIT distribution list. If you were not previously subscribed to the TPTF distribution list and would like to subscribe to the NIT distribution list, please access the ERCOT distribution list management website at http://lists.ercot.comhttp://lists.ercot.com –Meeting materials, agenda, and WebEx information will be distributed as soon as they are available –First Meeting will take place on Monday, June 22, 2009 9:30 am – 4:30 pm –The NIT Charter was distributed via email to NIT@lists.ercot.comNIT@lists.ercot.com The charter is embedded below for your review:

6. Lead from the front Texas Nodal Standing reports and updates ERCOT has published an updated version of the COMS - Verifiable Costs Submission Template v0.06 URL: http://nodal.ercot.com/readiness/golive/index.htmlhttp://nodal.ercot.com/readiness/golive/index.html External Interfaces Specification (EIS) 1.19 –Published to the ERCOT Readiness Center on 6/5 http://nodal.ercot.com/readiness/sandbox/documents/index.html http://nodal.ercot.com/readiness/sandbox/documents/index.html –ERCOT is currently receiving / reviewing comments and questions Send all comments and questions to eds3@ercot.comeds3@ercot.com Window for submitting comments closes on 6/19/09 Formal review of comments will be conducted during the first NIT (Nodal Implementation Team) Monday, June 22, 2009 9:30 am – 4:30 am

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 Standing reports and updates: Focused Input Testing Update Next testing will take place 6/16 – 6/18 Reminder: remaining FIT windows will only review telemetry and state estimator convergence. SCED inputs will be removed from FIT until further notice. ALL TIMES ARE CENTRAL DurationStart date and timeEnd date and time 27 hrs (3x9) June 16 - 8:00 amJune 18 - 5:00 pm 27 hrs (3x9) June 30 – 8:00 amJuly 02 – 5:00 pm 27 hrs (3x9) July 14 – 8:00 amJuly 16 – 5:00 pm

8. Lead from the front Texas Nodal Key Numbers  88.62% Test Average Convergence; 100% for 10 of 27 Test Hours; majority of issues attributed to zonal-nodal mismatches.  On Day One, the convergence rate for Hour Ending (HE) 0900 dipped to 55% owing to one ICCP link being down. Multiple manual replacements were made during HE 1000 and HE 1400 to address a disconnect issue and generation units coming online—convergence rates during these hours dipped to 85% and 71% respectively. Convergence rates achieved 92% or higher for the remaining six test hours for the day.  On Day Two, the convergence rate for HE 1400 dipped to 54% owing to two ICCP links being down. Multiple manual replacements were made during HE 1500 to address a disconnect issue and zonal-nodal mismatches. Convergence rates achieved 92% or higher for the remaining seven test hours for the day.  On Day Three, the convergence rate for HE 1500 dipped to 80% owing to multiple manual replacements being made to address zonal-nodal mismatches. Convergence rates achieved 92% or higher for the remaining eight test hours for the day. http://nodal.ercot.com 8 FIT III Assessment reports will be posted at: http://nodal.ercot.com/readiness/eds3/documents/index.htmlhttp://nodal.ercot.com/readiness/eds3/documents/index.html FIT III, Week 8 – State Estimator

9. Lead from the front Texas Nodal LFC6/25/2016 FIT Series WeekDateDay 1Day 2Day 3Average Convergence % for all Test Hours 100% Convergence Achieved FIT IIWeek 1Oct 21 – 23, 200890.1874.1691.8385.3912 of 27 hrs Week 2Nov 04 – 06, 200888.1796.5897.1193.9518 of 27 hrs Week 3Nov 18 – 20, 200887.1784.1982.9184.7612 of 27 hrs Week 4Dec 02 – 04, 200896.0493.3393.4494.2714 of 27 hrs Week 5Dec 16 – 18, 200894.7497.4996.3096.1819 of 27 hrs Week 6Jan 13 – 15, 200996.0094.1295.7895.3015 of 27 hrs Week 7Jan 27 – 29, 200994.0790.1393.2992.4914 of 27 hrs FIT III Week 1Feb 24 – 26, 200975.4578.8692.8582.3909 of 27 hrs Week 2Mar 10 – 12, 200996.8292.9798.4196.0720 of 27 hrs Week 3Mar 24 - 26, 200985.4594.9894.7091.7114 of 27 hrs Week 4Apr 07 - 09, 200997.1392.6097.4495.7221 of 27 hrs Week 5Apr 21 – 23, 200987.4789.8795.6591.008 of 27 hrs Week 6May 05 – 07, 200994.3494.4791.8793.5613 of 27 hrs Week 7May 19 – 21, 200996.8197.3697.0497.0718 of 26 hrs Week 8Jun 02 – 04, 200988.4784.0993.2988.6210 of 27 hrs Trends – FIT II & FIT III 9 One hour was removed from the Wk 7 test results to accommodate a nodal database load.

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 Q&A Q&A / Open Forum

11. Lead from the front Texas Nodal http://nodal.ercot.com 11 Deep Dive Topic: EIS 1.19 Changes EIS 1.19 Changes

12. Lead from the front Texas Nodal EIS 1.19 Changes Review by Section 2.3.6 - New Section - Enforced Precision information. –Market Submission and outbound Notifications (alerts, awards, etc.) – enforced at XSD level – inbound & outbound MW & MWh values - Enforcement of tenths of MW Prices: 2 decimal digits (cents) 2.3.7 - New section - XML Special characters –Handling of reserved characters in XML payloads (i.e., in Outage Creation “comments” field – use of &, ‘, “ etc.) 2.6 - Removal of the SLA numbers - referred to the ERCOT EDS SLA http://www.ercot.com/services/sla/http://www.ercot.com/services/sla/

13. Lead from the front Texas Nodal EIS 1.19 Changes Review by Section 3.3.9 – DC Tie Schedule – NERCTag is now part of the energy schedule - an MMS5 addition

14. Lead from the front Texas Nodal EIS 1.19 Changes Review by Section 4.0 Market Info updates: –4.3.8 Forecasted Load – Removed start/end time – Returns last available forecasted load values for next 7 days. –4.3.10 – MarketTotals – Removed start/end time- added OperatingDate – Returns market Total energy bought or Sold in DAM for the requested Operating Date –4.3.11 – LMPs/SPPs – Added Request/OperatingDate for DAM Market type Limited start/end time for RTM Market Type –4.3.12 – MCPCs Use TradingDate instead of StartTime/EndTime. Simplified the MCPCs structure –4.3.13 – Binding Constraints – Added Request/OperatingDate for DAM & DRUC market type – limited to end time for HRUC –4.3.16 –Dynamic Ratings Limited to EndTime on input. Returning 7 day data. –4.3.19 – LoadRatioShares – Limited to OperatingDate- returning full requested day information –4.3.20 - CompetitiveConstraints Limited to OperatingDate on input. Returning full requested day information. –4.3.24- AggregatedASOfferCurves Limited to OperatingDate on input. Returning full requested day information for DAM and all SASMs found.

15. Lead from the front Texas Nodal EIS 1.19 Changes Review by Section 4.0 Market Info updates: –4.3.25 – ASServicePlan Corrected the example –4.3.27 – StartupShutdownInstructions – Added report Date, Option addition for MarketType – replaced Start/EndTime with Trading Date –4.3.28 – TotalASOffers Limited to OperatingDate on input. Returning full requested day information for DAM market. –4.3.29 – TotalEnergys Limited to OperatingDate on input. Returning full requested day information for DAM market. –4.3.31 – WeatherInfo Limited to OperatingDate on input. Returning full requested day information. –4.3.39 - WGRPP Limited to EndTime on input. Returning hourly data for the requested hour. –4.3.40 – STWPF Limited to OperatingDate on input. Returning full requested day information. New 4.0 Market Info Interfaces: –4.3.49 – New Interface: MarketInfo: EndAdjPeriod –4.3.50 – New Interface: MarketInfo: TwoHrNotif –4.3.51 – New Interface: MarketInfo: P2ValidationSet

16. Lead from the front Texas Nodal EIS 1.19 Changes Review by Section 5.3.1.1 updated the MMS alerts – –added DRUC-CLOSE-NOTF 12.3.1 – Verbal Dispatch Instructions (VDI): MMS5 –Made “currentOprLevel” and “resource” elements optional –Added “finalOprLevel” and “finalState” elements 10.2. – Resource Parameters – MMS5 –Separated out the change/get/cancel operations – –Introduced cancel operation for Resource Parameters Set –Corrected “get” and “cancel” interfaces for resource parameter interfaces to use Request/ID=mRID instead of the payload.

17. Lead from the front Texas Nodal EIS 1.19 Questions / Comments Received Questions –Q: Are there any changes to the WSDL? A: No, this is the same WSDL implemented in 2007 –Q: Why are elements in the XSD diagram in the EIS displayed for a transaction type when they are not part of the message described in that section (paraphrased) A: ERCOT employs several complex type elements which serve as generic structures used across several messages Optional in this context indicates that element is applicable in only some cases For example: –For example, multiHourBlock is an optional element within the complex type PriceCurve. –AS Offer and Three Part Offer both use the complex type PriceCurve which contains the element multiHourBlock –When submitting an AS Offer, multiHourBlock is an optional, relevant part of that message. –Three Part Offers, however, make no use of multiHourBlock. Both AS Offer and Three Part Offer will display them when looking at the XSD diagrams in the EIS (External Interfaces Specification).

18. Lead from the front Texas Nodal EIS 1.19 Questions / Comments Received Questions (cont) –Q: Figure 19 shows a multiHrIndicator in the PriceCurve structure. Should this be the multiHourBlock element instead? A: Correct, it should read multiHourBlock and that EIS XSD diagram will be updated –Q: TmPoint/netTrade is defined in the EnergyTrade element table but not in any of the other Trade element tables. Why? A: netTrade is for EnergyTrades only. This is used to identify Purchase (“p”) or Sale (“s”) is the cases where a Dynamically Scheduled Resource (DSR) identifies itself as both, buyer and seller. Refer to protocol section 8.1.1.4.1 where this is described.

19. Lead from the front Texas Nodal EIS 1.19 Questions / Comments Received Questions (cont.): –A: The list of valid ASTypes for the AwardedAS interface differs between section 2.3.5 and the element table in section 4.3.2. Should the valid ASTypes for the AwardedAS interface be Reg-Down, REGUP-RRS-ONNS, and Off-Non-Spin as defined in section 2.3.5 or Reg-Up, Reg-Down, On- Non-Spin, RRS, and Off-Non-Spin as defined in section 4.3.2? Q: Ancillary Services Types are inconsistent in these sections. We will review all instances of these and correct accordingly. Awarded AS enumeration for ASTypes are Reg-Up, Reg-Down, RRS, Non-Spin. –Q: Should the SASMid element only be populated when the marketType is SASM? The AwardedAS sample XML (pg 120-121) shows marketType DAM and SASMid has a value. A: The example is incorrect and will be updated. For DAM Market there is no SASMid.

20. Lead from the front Texas Nodal EIS 1.19 Questions / Comments Received Comments: –C: Section 4.3.27 - Startup and Shutdown Instructions: Page 177 limits the Request/Market Type to HRUC and DRUC whereas page 178 mentions RUC Type as DRUC, HRUC, DAM. R: DAM will be removed from this list. –C: Section 4.3.27 - Startup and Shutdown Instructions: Page 178 includes Report generation Time (reportDate) as part of the Startup Shutdown container. But the example provided on page 179 for startup shutdown instruction (ERCOT response), for rucType = DRUC, does not include reportDate as part of the Startup Shutdown container. R: The example will be updated to reflect reportDate.

21. Lead from the front Texas Nodal http://nodal.ercot.com 21 Appendix

22. Lead from the front Texas Nodal http://nodal.ercot.com 22 Review of Overall Registration Data Project Schedule (originally presented 5/22/09)

23. Lead from the front Texas Nodal http://nodal.ercot.com 23 Review of Overall Registration Data Project Schedule http://nodal.ercot.com 23 Each window will be broken into 3 iterations with heightening levels of data quality goals All non-PUN RE’s will submit during 1 of 2 windows (except Wind) Each non-PUN RE will request one of the two windows between 5/22/09 and 6/5/09 via email to nodalmarkettransition@ercot.comnodalmarkettransition@ercot.com Some RE’s may be moved to a different window based on volume Planning and Protection data will be rolled in for the remaining windows (see next slide) All Wind resources will submit during the second window 2009 MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Private Use Network Transmission Data Collection Window 1 - Non-Wind* RE’s Transmission / Planning / Protection Data Collection - Iteration 1 - Iteration 2 - Iteration 3 - Iteration 1 - Iteration 2 - Iteration 3 Private Use Network Planning and Protection Data Collection Window 2 - Wind RE’s Transmission and Planning / Protection Data Collection - Iteration 1 - Iteration 2 - Iteration 3 MP-10 Phase 2 Final Validation SEM GO-LIVE 8/31 EIS 1.19 to EDS 8/10 85% Prod Quality 95% Prod Quality 98% Prod Quality 85% Prod Quality 95% Prod Quality 98% Prod Quality 85% Prod Quality 95% Prod Quality 98% Prod Quality Kick Off Market Call

24. Lead from the front Texas Nodal Registration Data Collection Update Iteration 3 of the Private Use Network Transmission Data Collection closes on 5/19/09 Current Production Quality Metric is 96.5% (goal is 98% by 5/19) 5/22/09 9:30AM – 11:00AM ERCOT will host a kick off for the next leg of the Nodal Registration Data Collection project Changes to Load Resource Registration The kick off meeting will cover the following topics: –Transmission data collection (review for non-PUNs / non-Wind) –Planning and Protection data review (inclusive of Private Use Networks) –Review of registration activities for the remainder of 2009

25. Lead from the front Texas Nodal http://nodal.ercot.com 25 EDS and Market Activities 2009 ( updated April 2009)

26. Lead from the front Texas Nodal http://nodal.ercot.com 26 Nodal Market Activity Update: EDS and Market Activities 2009 (updated April 2009) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2009 Verifiable Costs Training on NOMCR Open loop test Submission of Verifiable Costs for Resources (different dates for technologies) Resource Registration PUNS Transmission asset registration Telemetry and SE Focused Input Testing (Telemetry and SE) 7x24 ERCOT monitoring FIT w/ SCED begins All QSEs re-qualify DAM submissions Submission Testing SCED & DAM Publish v1.19 Sandbox v1.19 MMS+v1.19+UI+MPIMSCED submissions begin ** Official dates are available in the Integrated Project Schedule Network Model SEM Go-Live Milestone TSP model synchronization TSP MOD training COMS Extracts User Guide release Reporting “Get Reports” available All other RE’s Transmission asset registration QSEs w/ Res SCED re-qualification NDSML and extract supporting documentation updates

27. Lead from the front Texas Nodal http://nodal.ercot.com 27 Nodal API sub-group Report, by Transaction, Completion Confidence (originally presented on 2/6/09)

28. Lead from the front Texas Nodal http://nodal.ercot.com 28 Standing reports and updates: Nodal API sub-group (originally presented on 2/6/09) TPTF Action – Report, by Transaction, Completion Confidence –Each Transaction will be classified into 3 confidence levels –RED – Confidence low – high risk of change in the 1.18 and/or 1.19 releases –YELLOW – Changes should be limited to non-structural changes (e.g. enumeration changes) –GREEN – Any Changes will be limited to defects. –Note that if there are no changes in 1.18 and significant change in 1.19, a transaction will be marked as RED for both. It will retain that color until all changes are complete.

29. Lead from the front Texas Nodal http://nodal.ercot.com 29 Standing reports and updates: Nodal API sub-group (originally presented on 2/6/09)

30. Lead from the front Texas Nodal http://nodal.ercot.com 30 Standing reports and updates: Nodal API sub-group (originally presented on 2/6/09)

31. Lead from the front Texas Nodal http://nodal.ercot.com 31 Verifiable Cost Submission (originally presented on 4/17/09)

32. Lead from the front Texas Nodal http://nodal.ercot.com 32 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

33. Lead from the front Texas Nodal http://nodal.ercot.com 33 Verifiable Cost Submission ERCOT plans to roll out verifiable cost training: Verifiable Cost Training will cover: –What are Verifiable Costs –What data need to be submitted –Who is required to submit the data forms and supporting information –Where, when and how are Verifiable Costs used Current Plans: –Instructor Led Training during May/June –One session each in Austin, Houston and Dallas Please send any comment to nodaltraining@ercot.comnodaltraining@ercot.com