Lead from the front Texas Nodal 1 EDS 4 Outage Scheduler EDS Market Call May 30, 2008

Lead from the front Texas Nodal 2 ERCOT Anti-Trust 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.

Lead from the front Texas Nodal 3 Agenda Outage Scheduler –Release 9.2 update –External Web Services update –Q&A and Roll Call Appendix

Lead from the front Texas Nodal 4 Update on Outage Scheduler Current Status OS UI now available –The URL to access the Outage Scheduler is Next Weeks Market Test Schedule Luminant ((6/2) PM) LCRA ((6/2) 4 – 6 PM) CPS ((6/3) 9 – 11 AM) Topaz Power ((6/3) PM) AEP ((6/4) 9 – 11 AM) Exelon ((6/4) 1 -3 PM) Austin Energy ((6/5) 9 – 11 AM) EnergyCo ((6/5) 1 – 3 PM) Greenville Electric ((6/6) 9 – 11 AM) Completed UI Test LCRA TSP, Fulcrum Power Services LP, IPA Market Inc., ANP Funding LLC, BPTX, BTU (TSP & QSE), FPL, Oncor, Constellation, Calpine, City of San Antonio, Direct Energy, Centerpoint, Reliant Energy, Coral Power, Tenaska, Suez Energy, Brazos (TSP & QSE), NRG Future updates Recurring Planned Outages is now available Recurring, Grouped and Opportunity Outages through API, available date 6/6, with known issues Grouped and Opportunity Outages through UI, delayed until 6/30 WAN Update We have completed a capacity study with a few QSE volunteers Capacity is conducive to allowing a full market test ERCOT will update the WAN DNS with nodaleds.ercot.com on Monday 6/09/08. All QSE’s and TSP’s are permitted at that time to begin market submissions over the WAN ERCOT will continue to evaluate whether large reports and MIS will also be available over the WAN If issues are found, ERCOT will roll back the DNS entry and notify the market via a market notice Notifications will remain over the internet only

Lead from the front Texas Nodal 5 External Interface Spec V 1.14 documentation update Document update EIS V 1.14 was published to Nodal Readiness Center on 5/9/08 Sandbox compliant to EIS V 1.14 as of 5/22/08 EDS will be compliant to EIS V1.14 evening of 6/5/2008 –Known Issues Errors not always specific to real issue Group Opportunity Outages not available at this time

Lead from the front Texas Nodal 6 Q&A / Open Forum Roll-Call

Lead from the front Texas Nodal 7 -Release 9.2 Information -Connectivity information -Links to Key Documentation -Metrics -Data preparation APPENDICES

Lead from the front Texas Nodal 8 Outage Scheduler EDS 4.9.2: Objectives EDS Phase DescriptionPhase Objectives 9.2.1Forced Outage DetectionVerify the ability of the EMS to receive outage list from OS Verify the automation and timing of information from the OS to the EMS Verify the FOD capability of the EMS 9.2.2Connectivity / Submission test Verify MIS connectivity (if applicable) Verify EWS connectivity (if applicable) Verify MP’s ability to enter outages Verify ERCOT’s ability to approve single and group outages Verify QSE/TSP ability to receive updates on outage status 9.2.3Validation of PerformanceVerify OS ability to receive a specified quantity of data from multiple sources simultaneously via both the RUI and the EWS Verify OS data available for real-time reports 9.2.4Validation of Outage Evaluation in EDS Verify OS ability to send outage requests for the time period defined by the EMS user. Verify OS ability to receive outage status changes from the OE 9.2.5Validation of Outage Scheduler Interfaces Verify outage transfers from the OS into the DA TSA Verify outage transfers into RUC Verify outage transfers to all other uses of OS information 9.2.6Validation of Outage Postings in MIS Verify outage transfers from the OS into the MIS Validate MIS Secure Area access to Market Participants with the appropriate Digital Certificate Verify performance

Lead from the front Texas Nodal 9 Appendix - Outage Scheduler Testing: Basic Communications Test Prior to this test QSEs and TSPs using External Web Services will need to have their network and security teams make the following changes: –QSE’s / TSP’s Outage Scheduler system must be able to access: NOTE: this SSL URL is on port 80 –Market Participants must be able to receive / send transactions to/from the following IP ranges: / / /24

Lead from the front Texas Nodal 10 QSEs and TSPs using MIS (RUI) will need to have their network and security teams make the following changes: –Ports will be 80 and 443 –Market Participants must be able to receive / send transactions to/from the following IP ranges: / / /24 Appendix - Outage Scheduler Testing: Basic Communications Test

Lead from the front Texas Nodal 11 Key Documentation Key documents are available at

Lead from the front Texas Nodal 12 Outage Scheduler Tracking: Readiness Metrics TPTF approved MP20 to track MP ability to submit outages to the Nodal Outage Scheduler. Execution –MP’s that have met readiness metric MP20 by 6/13/08 are GREEN –MP’s that have attempted readiness metric MP20 by 6/13/08 are AMBER –MP’s that have not yet attempted readiness metric MP20 by 6/13/08 are RED ERCOT is calling all MPs that have not signed up for EDS4.9.2

Lead from the front Texas Nodal 13 Appendix- Outage Scheduler Reference: TSP/QSE Data Preparation If QSEs or TSPs need their equipment list to verify xml submissions, please to ERCOT is unable to post the information online for all QSEs and TSPs because of the size of the file