1. http://nodal.ercot.com 1 TSP Nodal Engagement Market Participant Call ERCOT June 16, 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. 8-Hour LFC Test Update General Reminders Update for Network Operations Model NDSWG update Planning Model activities SSWG update TSP Outage Scheduler activities Nodal Scorecard Update Agenda http://nodal.ercot.com 3

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

5. http://nodal.ercot.com 5 8-Hour LFC Test Update

6. http://nodal.ercot.com 6 8-Hour LFC Test Update –8-Hour LFC Test Update 8-Hour Test has been confirmed for tomorrow 6/17/2010 ERCOT will send an additional notice tomorrow morning 3 hours prior to the test starting to confirm once more time The test will not start prior to 10am 8-Hour Approach Document is located at : http://nodal.ercot.com/readiness/markettrials/rtm/index.html http://nodal.ercot.com/readiness/markettrials/rtm/index.html

7. http://nodal.ercot.com 7 General Reminders

8. http://nodal.ercot.com 8 General Reminders –Nodal Modeling and Outage Scheduler Go-Live will be discussed at the following Stakeholder meetings: NATF 6/23/2010 TAC 7/1/2010 – ERCOT will release the 168-Hour Handbook on 6/30/2010 Initial presentation on the 168-Hour handbook to take place on 7/8/2010 at NATF Workshop for all MPs will occur on 7/28/2010 during the Market Readiness Seminar (MRS) #5 MRS #5 information is located at: http://www.ercot.com/calendar/2010/07/20100728-MT http://www.ercot.com/calendar/2010/07/20100728-MT

9. http://nodal.ercot.com 9 General reminders / updates ERCOT has developed a user guide along with a web-based user interface training module to introduce the user interface and provide ongoing reference material for end users of the application. The introductory sessions are targeted at personnel from TSPs, QSEs and Resource Entities and are intended to: –Review ERCOT market rules related to outage coordination –Describe roles and responsibilities for ERCOT and market participants –Introduce the use and design of the Outage Scheduler –Demonstrate the basic functions of the Outage Scheduler –Describe the interfaces between the outage scheduler and other Nodal Market applications. TSPs and QSEs are encouraged to send personnel that will either submit or maintain outage information on the Outage Scheduler as well as those that may need to generate reports on outages. The location and schedules of the course are shown below: Date Time City Address 22-Jun-1009:00 to 15:00Austin, TX ERCOT Austin 7620 Metro Center Dr. Austin, TX 78744 28-Jun-1009:00 to 15:00Dallas, TX Oncor Energy Plaza 1601 Bryan St. Dallas, TX 75201 15-Jul-1009:00 to 15:00 Houston, TX CenterPoint Energy Energy Control and Data Center 16303 Tomball Parkway Houston, TX 77065

10. Update for Network Operations Model http://nodal.ercot.com 10

11. ERCOT TAC Meeting - ROS Report 03/04/2010 Ken Donohoo 11 Nodal Model Effort Activity Operations Model (NMMS) CRR Model Topology Processor (Software) Long Term Planning Model NDSWG Support SSWG Support SSWG Support SSWG & ERCOT Development

12. Update for Network Operations Model Network Operations Model Validation: No change 24 of 28 TSPs have submitted confirmation that validation complete Represents 99.9% of the modeled system equipment Materials still available from last TSP validation workshop http://www.ercot.com/calendar/2010/04/20100409-MTTSP NMMS System Update 5/12/2010 – Citrix unavailable Specific issue is resolved and no additional occurrences have been observed Update on Oracle Performance Issues: Oracle patch resolved the Oracle performance issue Update: Issues with NMMS data templates and data consistency Received 2 separate patches from the vendor ERCOT is monitoring to verify that the issue has been resolved Update: Issues with PTC and NOMCR’s No change No ETA received from the vendor at this time http://nodal.ercot.com 12

13. NDSWG Update – June 2010 Nodal Transition Plan –Met on June 3 at TAC direction to work with ERCOT on nodal go-live transition timeline and associated issues. –Resulting agreements to transition plan ERCOT and Market Participants collectively agree through NDSWG to the transition timeline given the following clarifications –ERCOT will accept all interim updates during the transition period. –Market participants will enter pre-defined reasons justifying interim update as outlined. (to be added to modeling expectation white paper) –ERCOT will track and report interim update performance only to NDSWG and the affected MP’s management team. –ERCOT to modify the table reflecting data submission deadlines consistent with transition plan (slide 2). ERCOT to confirm submission deadline time (per software configuration) NDSWG to have subsequent discussion regarding interim update protocol implications

14. De c JanNovOctSe p AugJulyJun Zonal Process Transition Process Initial Validation (ERCOT) Market Validation (Market Participants) Final Validation (ERCOT) NOMCR Processing Cases Used in Production Deadline for Model Changes Nodal Go-Live Nodal Production Process Public Posting Transition Plan

15. NOGRR034 – ROS approved at their June 10 meeting. NOGRR034 will initially lower metrics and grey-box language on outage tracking system for implementation at a later date after market start. –NDSWG will be revising the telemetry metrics document and submitting to ROS and TAC for approval. A special meeting to discuss the metrics revision will be scheduled in July or August. NPRR146 – TAC did not approve the ROS recommendation and instead approved ERCOT’s version of the NPRR. MP’s will have until the 15th of the month prior to the equipment in service date to update ICCP names. The last NDSWG meeting was focused on review and comments to the Modeling Expectations Whitepaper being developed by ERCOT. There are still significant unresolved issues. –How to Handle interim updates within the modeling timelines. –The use of the outage scheduler to manage the energization and retirement of equipment. Some concerns with safety issues when managing outages on equipment that may not exist due to model load frequency. –Pseudo devices and the management of those devices within the model. There are still performance issues with NMMS that need to get resolved.

16. Planning Model activities Supporting Monthly CRR Auction http://nodal.ercot.com 16

17. ERCOT TAC Meeting - ROS Report 03/04/2010 Ken Donohoo 17 Nodal Model Effort Activity Operations Model (NMMS) CRR Model Topology Processor (Software) Long Term Planning Model NDSWG Support SSWG Support SSWG Support SSWG & ERCOT Development

18. SSWG Planning Model Activities Correcting Connectivity Node Groups –June 11 TP output: 247 CNGs needing correction 28 CNGs left that ERCOT originally populated with numbers because they could not be matched to an existing PSSE bus TSPs will correct these 28 ASAP

19. SSWG Planning Model Activities Status of missing IDs: Branches and loads Phase II Corrections: Area #, Zone #, Load ID, Branch ID, Generator ID –Due July 8 New Topology Processor update delivered to ERCOT –SSWG has submitted a System Change Request (SCR759) related to the Topology Processor changes Will ask ROS for approval in July NPRR224 was recommended for approval by PRS, next step is PRS IA review. Identifying important modeling issues –Categorize these and determine if additional SCRs are necessary

20. SSWG Modeling Issues Annual Planning Model related issues: Off-nominal transformers: TP not calculating impedances correctly? Cap banks and reactors: Control mode in TP output is incorrect in many cases Transformer modeling: 2 winding vs 3 winding No ratings on zero impedance line segments Ownership Loads and cap banks being collapsed to the correct CNGs Cap banks connected to distribution voltage FACTS devices Future versions of PSSE

21. SSWG Nodal Schedule June – AugustMake remaining changes to IMM prior to Planning Go-Live June 18Remaining 99XXXX and 8XXXXX CNG changes due to ERCOT June 21ERCOT to send spreadsheet with Phase II information July 8Phase II changes due to ERCOT July TSPs Complete changes based on TP enhancements July 12-13MOD/PMCR training (email SSWGData@ercot.com to reserve spot)SSWGData@ercot.com July 15-16MOD/PMCR training July 19-20MOD/PMCR training July 22-23MOD/PMCR training AugCompare TP output to SSWG 2010 summer peak case NovCreate 2012 summer peak case using TP and MOD Dec – Feb 2011Review, update, and modify TP/MOD process for case creation Dec 1Nodal Go-Live Mar – April 2011Assuming Nov test meets SSWG approval, begin work to create 12DSA using Nodal method

22. TSP Outage Scheduler activities http://nodal.ercot.com 22

23. TSP Outage Scheduler http://nodal.ercot.com 23 Qualification activities in-flight Weekly Market Call every Friday 9-9:30am http://www.ercot.com/committees/nodal/mt/index Handbook for Outage Scheduler Activities http://nodal.ercot.com/readiness/markettrials/os/index.html OS Qualification Status No change 23/25 TSPs 99.8% complete Equipment Share

24. Nodal Scorecard Update http://nodal.ercot.com 24

25. Telemetry Quality Update Telemetry Quality Dashboard –6/11 Snapshot Total Suspect – 1578 points Common suspect points since the first 5/11 snapshot – 758 –Point lists distributed after each snapshot –Dashboard posted at http://nodal.ercot.com/readiness/markettrials/rtm/i ndex.html http://nodal.ercot.com/readiness/markettrials/rtm/i ndex.html SE Telemetry Standards Report –Q2 SE Telemetry Report data loading until the end of June –MP23 Telemetry Quality Metric will not begin until reports are available on the MIS Communication –Contact ERCOT EMS Production Support (ercoticcpsupport@ercot.com) with any questionsercoticcpsupport@ercot.com http://nodal.ercot.com 25