1. http://nodal.ercot.com 1 TSP Nodal Engagement Market Participant Call ERCOT July 14, 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. General Reminders / Updates Update for Network Operations Model NDSWG update Planning Model activities SSWG update TSP Outage Scheduler activities Agenda http://nodal.ercot.com 3

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

5. http://nodal.ercot.com 5 LFC Testing Update

6. http://nodal.ercot.com 6 LFC Update –ERCOT will conduct a 5-Hour LFC test next week The test will occur on the 7/20, 7/21 or 7/22 A Market notice will be distributed 2 business days prior to the test to confirm the date Telemetry quality will be monitored in the days leading up to the test Outreach on telemetry issues will continue up until and during the test –Modifications in the Market Trials activities NATF raised discussions on the need for additional Market Trials activities during the month of September The focus will shift to incorporate more closed loop testing Discussions regarding the 168-Hour and its associated benefits will continue with the market A revised schedule will be developed and initially presented to NATF

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

8. http://nodal.ercot.com 8 General Reminders –Nodal Modeling and Outage Scheduler Go-Live: Was covered at both, NATF on 6/23 and TAC on 7/3 Presentation materials are located at the following links: NATF: http://www.ercot.com/calendar/2010/07/20100708-NATF TAC: http://www.ercot.com/calendar/2010/07/20100701-TAC http://www.ercot.com/calendar/2010/07/20100708-NATF http://www.ercot.com/calendar/2010/07/20100701-TAC –Interim Updates will be presented next at NDSWG on 7/20/2010 http://www.ercot.com/calendar/2010/07/20100720-NDSWG http://www.ercot.com/calendar/2010/07/20100720-NDSWG

9. Technical Advisory Committee 01 July 2010 Current State of NMMS Production system The System installed August, 2009: Database and System of Record for Nodal and Entry Point for Zonal. Issue: System has not been stable NMMS System had a software defect that impacted how the system managed computer memory. The application restarted itself or crashed when a memory error was detected. A restart frequently caused TSPs to lose interim model changes. Progress On Friday July 2 nd, a parameter change was made to the NMMS Database application (Oracle) The change affected the memory allocation process when accessing the database. There have been no system restarts attributable to memory management since fix was applied. There were unrelated restarts July 6 th and July 8 th but the root cause was not the elusive memory issue. Next Steps Install one additional stability patch Measure and improve performance (navigation & validation) Network Model Management System July update

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. NDSWG Update – July 2010 The NDSWG has not formally met since the last ROS meeting. TSP’s have been involved in identifying a list of outstanding issues that need to be resolved by the TSP’s and ERCOT. This was requested by NATF in order for them to determine if they could certify that TSP’s are ready for market go-live. They are also working on a similar set of issues for QSE’s. 47 issues have been identified, their impacts to TSP’s and assigned priorities (1-4). 1 = Show stopper; Needs resolution before Go-live can be accomplished. 2 = High priority issue that should be resolved by Go-live 3 = Needed but can be implement post Go-live 4 = Needed by Planning Go-Live (approximately March 2011) NDSWG, NATF and ERCOT are planning on trying to resolve these issues in the next couple of weeks.

13. There are still significant performance issues with NMMS that need to be resolved. This is a high priority and needs ERCOT’s and their vendors full attention.

14. ERCOT TAC Meeting - ROS Report 03/04/2010 Ken Donohoo 14 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

15. SSWG Planning Model Activities Correcting Connectivity Node Groups –July 9 TP output: 188 CNGs needing correction All CNGs that ERCOT originally populated with numbers because they could not be matched to an existing PSSE bus have been given new bus numbers Phase II Corrections: Area #, Zone #, Load ID, Branch ID, Generator ID, mileage –ERCOT sent correction spreadsheet July 9 –Due July 30

16. SSWG Planning Model Activities New Topology Processor update delivered to ERCOT –Some features are not working properly. August test is in jeopardy if features do not work by then. –SSWG has submitted a System Change Request (SCR759) related to the Topology Processor changes Will ask ROS for approval at July 15 meeting NPRR224 was approved by TAC, next step is BOD approval (July 20 meeting) Identifying important modeling issues –Categorize these and determine if additional SCRs are necessary –SSWG to work on drafting next SCR MOD/PMCR Training in July –MOD Sandbox to be opening for TSP access –ERCOT and TSPs will meet to correct the remaining 188 CNG problems

17. SSWG Modeling Issues Annual Planning Model related issues: Off-nominal transformers: TP not calculating impedances correctly 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

18. SSWG Nodal Schedule June – AugustMake remaining changes to IMM prior to Planning Go-Live 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 July 30Phase II changes due to ERCOT July TSPs Complete changes based on TP enhancements 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

19. TSP Outage Scheduler activities http://nodal.ercot.com 19

20. TSP Outage Scheduler http://nodal.ercot.com 20 Open Outage Scheduler testing completed on 7/13 Currently, test outages may be submitted for effective dates Sunday or Monday through the month of August Realistic outage updates or entry of actual missing outages Tuesday – Saturday Outage Scheduler with Zonal Outage Transfer (prep for September Market Trials and Transition plan) Delete all Outages and run Zonal to Nodal Transfer Tool Friday, 8/13 (Note that 80% to 85% of the outages are transferred) A Market Notice will be sent out once the purge and transfer is complete Email MarketTrials@ERCOT.com by 8/9/10,1700 if the transfer is NOT desiredMarketTrials@ERCOT.com Resource Outages will not be transferred by the Transfer tool The target is to make available for outage transfer validation and outage submissions Monday 8/16, 7:00 am, for the 168 hour test, optional months of October & November and for December and beyond Request list of Outages not transferred from MarketTrials@ERCOT.comMarketTrials@ERCOT.com Send email to Market MarketTrials@ERCOT.com confirming outages have been validated by 9/17 for all Outages December and beyondMarketTrials@ERCOT.com First production pull of OS data is scheduled for 10/2 for the first CRR Auction TSPs are responsible to ensure that the outages in the Nodal Outage Scheduler are correct