1. http://nodal.ercot.com 1 Market Trials Outage Scheduling Weekly Update September 03, 2010

2. http://nodal.ercot.com 2 Outage Scheduling Agenda Standing Reports and Updates –Outage Scheduling General reminders / updates –Known Issues Question and Answers / General Discussion

3. http://nodal.ercot.com 3 General reminders / updates Reminder: Outage Scheduling Activities 08/30/2010: Complete validation and entry of outages effective in September 09/01/2010 – 09/30/2010: Started: Maintain outages effective in September 09/17/2010: Complete validation and entry of outages effective in December and beyond 09/17/2010: Send email to markettrials@ercot.com verifying completion of validation / entry of post Go-Live outagesmarkettrials@ercot.com 09/17/2010 – 11/30/2010: Maintain outage effective post Go-Live. Companies to be contacted today regarding outage synchronization QSEs AMOCO OIL COMPANY BRAZOS ELECTRIC POWER CO OP INC CITY OF AUSTIN DBA AUSTIN ENERGY (RES) CITY OF GARLAND (RES) COLLIN POWER COMPANY LLC FORMOSA UTILITY VENTURE LTD INGLESIDE COGENERATION LIMITED PARTNERSHIP LUMINANT GENERATION COMPANY LLC (RE) SHERBINO I WIND FARM LLC (RE) SOUTH HOUSTON GREEN POWER LP THE DOW CHEMICAL CO TSPs CPS San Antonio AEP LCRA STEC Texas Municipal Power Pool Oncor

4. http://nodal.ercot.com 4 Environment Report: Known Issues Known issues posted to the readiness center at: http://nodal.ercot.com/readiness/markettrials/os/index.html http://nodal.ercot.com/readiness/markettrials/os/index.html Newly Opened Issues (verbal update) StatusIssueDescription Work Around/Comments Open MP reported they cannot submit a group outage MP reported they are not able to enter an outage on a breaker that is jointly operated by the MP. Investigating the issue Open MP reported the OS UI summary page is painting twice on the same screen Investigating the issue Open MP reported they are unable to enter an Actual End in outage Investigating the issue

5. http://nodal.ercot.com 5 Q&A Q&A / Open Forum