1. http://nodal.ercot.com 1 Market Trials Outage Scheduling Weekly Update July 09, 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. http://nodal.ercot.com 3 Agenda Anti-trust Admonition Environment Report –Planned / unplanned outages –CIM Load –Known Issues Standing Reports and Updates –General reminders / updates Question and Answers / General Discussion ERCOT asks that Market Participants log into the WebEx session using their company name and then their name. This will allow ERCOT to take roll-call offline

4. Market Trials 2010 Roadmap http://nodal.ercot.com 4 To be updated with new LFC testing schedule

5. http://nodal.ercot.com 5 Day-to-day operations summary: Planned / Unplanned Outages of NPROD / CIM Load Planned Outages –07/09/2010 6:00 P.M. – 10:00 P.M. EWS and OS UI application services will be unavailable as a result of software migrations being planned during this period ( Note: EWS version 1.19M will take into effect upon completion of this migration). Unplanned Outages –7/02/2010 – 8:00 A.M. – 4:30 P.M. Due to the CIM data load on 7/1/2010, station names were changed from the short acronym to their long name. The name change was reversed in the late afternoon. Target CIM Load dates for the month of July / August –7/14/2010 – Note that this database load may be delayed due to the 5- Hour LFC test the week of the 19 th. This will be communicated via a market notice. –8/2/2010

6. http://nodal.ercot.com 6 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 remaining courses are shown below: Date Time City Address 15-Jul-1009:00 to 15:00Houston, TX CenterPoint Energy Energy Control and Data Center 16303 Tomball Parkway Houston, TX 77065

7. http://nodal.ercot.com 7 General reminders / updates Update: ERCOT will be opening a window of optional Outage Scheduling testing –Testing opened on 7/1/2010 and close end of business on 7/13/2010 Change in schedule is to provide additional time due to the station name defect introduced on 7/1/2010 –During this period Outages will be de-coupled from the DAM to allow MPs flexibility to test varying scenarios –MPs should contact ERCOT in advance to coordinate approvals or other scenarios Update: Outage Scheduler Nodal Transition Plan –Was presented to NATF on 7/8/2010 –NATF voted to recommend TAC approval of the market readiness criteria –Will be presented to TAC on 8/05/2010

8. http://nodal.ercot.com 8 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 New Known Issues: StatusIssueDescriptionWork Around/Comments Open Naming convention for lines and line segments If a line doesn't have a line segment name a 1 is added to the end of the line name.ERCOT is looking into this issue. OpenTOO DD and HH Issue When submitting a TOO the outage duration can't exceed the opportunity window. working with the vendor to correct this issue. Open The TOO pick list for HH has the values for minutes not hours: the values should be 0 to 23 not 0 to 59 When entering the Transmission Opportunity Outage duration hours, the OS UI is displaying 59 hours. If the TOO duration needs to be longer than 23 hours use the days and hours combination.

9. http://nodal.ercot.com 9 Environment Report: Known Issues Closed Issues (will be closed with today’s release): StatusIssueDescription Closed On a Forced Extension the user is able to enter a New Planned End that is the same as the Planned End. This should draw an Error. When the user enters the New Planned end on a Forced Outage it should be greater than the Planned End. The system is allowing the the New Planned End to be the same date/time at the Planned End. The New Planned End should always be greater than the Planned End. Closed Copy outage for QSE ROO in each stage isn't displaying the correct fields Then the user copies an ROO type outage, the resulting display should default to a Planned Outage. Closed Client side validation is not being displayed for missing date fields on Group TOO. In the OS UI on a Group TOO, when the user is entering the Earliest/Planned Start Latest and leaves one of the date fields blank, the error message is "Displays Authentication failure. Please contact the ERCOT Help Desk at (512)248- 6804". They should get a client side validation error asking for the missing required date/times. Closedfrom the OS UI, TOO - Need to trigger the cancel pick list in ENYS The user can't cancel a TOO once the designated resource has been submitted and the TOO Status is ENYS. ClosedCan't add a note in stage 1 of a TOO Once the TOO has been submitted in Stage 1, the user can't add notes. This would be before the TOO has had a match with a designated resource outage. Closed OS UI Custom Filter - TSP only- Operating Company is not defaulting to the Certificate Company. When the TSP user uses the Custom Filter to look for only their outages, the "Requesting Company" should default to the Company that is logged in. Closed Warning late with actual start is not achnowledged even after enering the actual start The "Late with Actual Start" warning is not clearing once the Actual Start has been entered. Closed on a Forced Extension resource outage, supporting notes can't be added after the Actual End has been entered Once a forced outage has been extended and the Actual End has been entered, Supporting Notes can't be entered to clear the warning.

10. http://nodal.ercot.com 10 Q&A Q&A / Open Forum