1. http://nodal.ercot.com 1 Market Trials Outage Scheduling Weekly Update August 20, 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 Outage Scheduler Transition to Go-Live 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

5. http://nodal.ercot.com 5 Day-to-day operations summary: Planned / Unplanned Outages of EDS Planned Outages –08/20/2010 12:00 P.M. – 08/20/2010 6:00 P.M. Application patch deployments are planned in the Nodal production environment and will intermittently affect services rendered by the following systems –OS –OS-UI –EWS ( Web Services) Unplanned Outages –08/13/2010 09:00 A.M. – 08/13/2010 11:00 A.M A Hardware outage on one of our AIX frames in the Austin datacenter forced an emergency site failover of the Nodal production systems over to the Taylor center. ERCOT’s infrastructure team, along with IBM, is investigating the cause of the failure. The following application services were affected as a result of this outage. –OS –OS-UI –EWS ( Web Services) Network Model Load Dates –08/17/2010 – completed as scheduled –09/01/2010

6. http://nodal.ercot.com 6 General reminders / updates Update: Outage Scheduler with Zonal Outage Transfer Purging of test data and Zonal to Nodal Transfer completed the morning of 8/16/2010 as planned at 10:30 AM TSPs / QSEs should now be working on validating outages effective for September, 2010 and December 1, 2010 and later. Reminders: Resource Outages were not transferred by design 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

7. http://nodal.ercot.com 7 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 Deferred Issues: StatusIssueDescriptionWork Around/Comments deferr ed MP request - add more characters to the group name When submitting a group outage the Group Name is limited to 8 characters. Enhancement requested by a market participant deferr ed Change what is displayed in the Outage Scheduler requestor when using the API/EWS When a user submits an outage using the API the user name is the duns number and should be the name of the user requesting the outage Enhancement requested by a market participant deferr ed Custom Filter - Operating Company does not stay highlighted after the apply button is selected When the user uses the custom filter, the next time the filter is opened, the Operating Company is not selected. MP will select the Operating Company. deferr ed When you delete a row from a group on create it it will clear the group name causing the user to have to re- enter group name before submitting When you delete a row from a group on create it it will clear the group name causing the user to have to re- enter group name before submitting. This only affects the QSE resource outages. The User will re-enter the group name before submittin. deferr ed OS UI - Warnings that do not require an action by the user are not being removed from the warnings table Warnings that come in for an Opportunity Outage that do not require an action by the user are not being removed by the system.ERCOT is looking into this issue.

8. http://nodal.ercot.com 8 Environment Report: Known Issues Newly Closed Issues: StatusIssueDescription closed Related equipment only displays 100 rows, so lines over 100 are missing all rows over 100 If related equipment is selected for a Line or a transformer and there are more than 100 pieces of equipment, the OS will only display 100 of the pieces. closed OS 2.2.5 Group outages - QSE & TSP - conflict when an existing outage exists of any type. When submitting a group outage, it there was an existing outage in the system, the user would get a Conflicting Outage error message even though the outages did not conflict. closed Related Equipment does not display the Normal State or Outage State on DSC when select by related eq table When the user used the Associated Equipment to add to a group outage on a tie line, the breakers and switches operated by the adjoining company wasn't displaying the Normal position or the Outage pasition. When the user submitted the request they recieved an error that the Outage State was missing. closed EIP External Interface Spec Doc update - Work Codes are missing descriptions In EIP v1.19n, four nature of work codes were added to section 7.2.1: CW, FP, NE, OE; however, their corresponding descriptions were not added. Could you provide the descriptions to those codes?

9. http://nodal.ercot.com 9 Q&A Q&A / Open Forum