1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS 4 Outage Scheduler EDS 4.9.2 Market Call April 18, 2008

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

3. Lead from the front Texas Nodal http://nodal.ercot.com 3 Agenda Outage Scheduler –Current issues –Release 9.2 update –Q&A and Roll Call Appendix

4. Lead from the front Texas Nodal http://nodal.ercot.com 4 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

5. Lead from the front Texas Nodal http://nodal.ercot.com 5 Update on EDS 4 Environment Outage Scheduler, UI and associated External Web Services migrated to EDS –Internal testing in progress Testing with market participants being moved out 4 weeks. Testing to begin the week of 5/12 MPs currently scheduled for weeks 4/21 thru 5/5 will be rescheduled for another slot. ERCOT will call the MP contacts and reschedule according your convenience For convenience additional timeslots will be made available –Monday afternoons 1 – 3 PM –Late afternoons (Tues. thru Thur.) 4 – 6 PM –Friday mornings 9 – 11 AM External Web Services will be compliant to EIP Specification v1.12 Current known issues –Opportunity outage being redesigned, will be available for MP testing mid-May –UI and web services still be tested and tweaked –Inconsistent results when trying to submit outages

6. Lead from the front Texas Nodal http://nodal.ercot.com 6 Market Participants not yet signed up for Outage Scheduler testing Coral Power (QSE) Coral Power LLC BRYAN TEXAS UTILITIES (TSP) FPL Energy Power Marketing FPL Energy Power Marketing (SQ3) FPLE PMI (SQ1) FPLE_WIND_FPL ENERGY POWER MARKETING INC.(SQ2) GREENVILLE ELECTRIC UTILITY SYSTEM (TSP) LCRA (TSP) Medina Electric Corporation (TSP) MAGIC VALLEY ELECTRIC CORPORATION(TSP) Rayburn (TSP) STEC(QSE) Scurry County Wind (QSE) South Texas Electric Co Op(TSP) TEXAS MUNICIPAL POWER AGENCY (TSP) TEXAS NEW MEXICO POWER(TSP) Westar (QSE) City of College Station City of Denton

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 Updates – Documentation Changes to Outage Scheduler XSDs –Nodal sandbox compliant with EIP version 1.12 –XML samples in the test package will be revised by COB 4/18/2008 –Changes in EIP V1.12 include – name of element changed from “Reoccuring” to “Recurring”

8. Lead from the front Texas Nodal http://nodal.ercot.com 8 Follow up from Kick Off meeting on 4.9.2 – Performance test The approved OS handbook includes the following text on Performance test Phase Overview –The objective of this phase of the release is test the ability of the Outage Scheduler to simultaneously handle requests from multiple MPs with the intent to simulate real-world loading of the OS. The Validation of Performance phase will last two weeks beginning June 16, 2008. EDS Testing Activities –ERCOT will designate roles and testing periods for entry into the Outage Scheduler. The roles will consist of some MPs using their API to enter outages while others enter information using the RUI. Outages for both resources and transmission elements will be submitted simultaneously. The testing periods will be from 9 AM until 11 AM for the first week of the phase. ERCOT will designate a quantity of outages to be entered during each two hour window as well as the method for entry. Additional performance validation may be required for the second week of the phase. Market Participant Involvement –In order to thoroughly test the OS it will be necessary for MPs to participate in each of the test windows Participation from all TSPs and QSEs is required for 2 hours each day for upto 2 weeks

9. Lead from the front Texas Nodal http://nodal.ercot.com 9 Q&A / Open Forum Roll-Call

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 -Release 9.2 Information -Connectivity information -Links to Key Documentation -Metrics -Data preparation APPENDICES

11. Lead from the front Texas Nodal http://nodal.ercot.com 11 Appendix - Outage Scheduler 4.9.2 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: https://nodaleds.ercot.com:80/2007-08/Nodal/eEDS/EWS/ NOTE: this SSL URL is on port 80 https://nodaleds.ercot.com:80/2007-08/Nodal/eEDS/EWS/ –Market Participants must be able to receive / send transactions to/from the following IP ranges: 66.128.16.0/24 66.128.17.0/24 66.128.18.0/24

12. Lead from the front Texas Nodal http://nodal.ercot.com 12 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: 66.128.16.0/24 66.128.17.0/24 66.128.18.0/24 Appendix - Outage Scheduler 4.9.2 Testing: Basic Communications Test

13. Lead from the front Texas Nodal http://nodal.ercot.com 13 Key Documentation

14. Lead from the front Texas Nodal http://nodal.ercot.com 14 APPENDIX- DAM/RUC 4.9.2 Tracking: Readiness Metrics MP8 - QSE Ability to Submit Transactions Via MIS –Expected completion date June 13 MP9 – QSE Ability to Submit Web Service Transactions –Expected completion date June 13 Execution –MP’s that have met readiness metric M8 or M9 by 6/13/08 are GREEN –MP’s that have attempted readiness metric M8 or M9 by 6/13/08 are AMBER –MP’s that have not yet attempted readiness metric M8 or M9 by 6/13/08 are RED In addition, ERCOT is drafting another metric MP20 to track MP ability to submit outages to the Nodal Outage Scheduler ERCOT is calling all MPs that have not signed up for EDS4.9.2

15. Lead from the front Texas Nodal http://nodal.ercot.com 15 Appendix- DAM/RUC 4.9.2 Reference: QSE Data Preparation If QSEs or TSPs need their equipment list to verify xml submissions, please email to EDS4@ercot.comEDS4@ercot.com ERCOT is unable to post the information online for all QSEs and TSPs because of the size of the file