1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS 3 Release 5 and 6 Friday Market Updates Oct 03, 2008

2. Lead from the front Texas Nodal http://nodal.ercot.com 2 Agenda Antitrust Admonition Roll Call SCED Update –Submission Metrics Update –Updates / Questions / Reminders LFC / State Estimator Update Q&A / Open Forum API Subgroup Topics

3. Lead from the front Texas Nodal http://nodal.ercot.com 3 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.

4. Lead from the front Texas Nodal http://nodal.ercot.com 4 Submission Metrics Update 9/27/20089/28/20089/29/20089/30/2008 N/A72%12N/A80%6N/A74%10N/A65%8 COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS Submit the following for each trade date: –Three Part Offer or Output Schedule EOC only required. Should cover 80 – 120% of cost Min Energy / Start-up may be zero’d out FIP/FOP must sum to 100% –COP Only required if submitting an Output Schedule No updates in the adjustment period required Note: a COP is also required in order to submit during the adjustment period (this will be changed to a warning in the next release of MMS  MMS4) 10/1/200810/2/200810/3/2008 N/A73%10N/A79%13N/A80%14 COP TPO IDOOSCOP TPO IDOOSCOP TPO IDOOS

5. Lead from the front Texas Nodal http://nodal.ercot.com 5 Updates / Questions / Reminders Unplanned Environment Outages –MMS 9/26 09:00AM – 10:10AM – Market database exhausted all connections. Application issue. 9/29 08:40AM – 10:30AM – Two Issues 1)MMS database Password expired and 2) MMS processing transactions extremely slow; related to performance issue with handling large payloads. External Interfaces Specification 1.17 –ERCOT will release a draft copy to the readiness center on 10/17/08 –Comments may be sent to eds3@ercot.comeds3@ercot.com –Target completion 1.17 is 11/15/08 –Sandbox migration target is 12/1/08 –EIS 1.17 will never go to EDS

6. Lead from the front Texas Nodal http://nodal.ercot.com 6 Updates / Questions / Reminders EIP 1.17 Changes: –5.3.15 – Added DAM AS InsufficiencyReport notification. –5.3.11.1 – Added MMS System generated Alerts –5.3.11.2 – Added EMS System generated Alerts –Added wording regarding Dispute/Attachment/document compression (if need be). –Removed VDI from ResourcePar (Sec 10.3.4) and added it as an independent container/noun in Section 12. –Added Sections 4.3.46 – MarketInfo - AS Obligations 4.3.47 – MarketInfo – Startup/Shutdown Instr. 4.3.48 – MarketInfo - AS InsufficiencyReport –4.3.20 – updated competitive constraints Figure with startTime/endTime –4.3.41 corrected DynamicRatingsDeviations (plural) –4.3.42 corrected AvgMonthlyDynamicDeviations (plural) –4.3.24 Added MarketType (DAM/SASM) to AggregatedASOfferCurves –11.2.1 Added Dispute Types, Sub-Types, and Charge Types cross reference table – figure 212 –12 and 10 - Res Par -changed normalRrCurve, emergencyRrCurve, Details, reasonrr, and ReasonabilityLimits maxOccur to 1 as these are not hourly values. –5.3.1.1-2 Updated MMS and EMS Alerts –3.3.2 figure 20 – tagged SuMeFipFop as optional – updated the example 3PO BidSet example –7.2.2 – Added Ad-Hoc Query to get Outage

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 Focused SE & System Constrained Economic Dispatch Testing (SCED) Clarification on market notice sent on 09/25 –Under Continuing Submission Requirements section, the following is stated: Each online resource must have in place a COP, which reflects the expected Reserve Status and LSL/HSL. COP schedules are not required; therefore they may be zeroed out. Correction: For continuing submissions, COP’s are only required in the following scenarios: 1) I f submitting an Output Schedule 2) Submitting a TPO / OS during the adjustment period (note that this will be changed to a warning in the next release of MMS) The COP is not required to be updated –Addition to the Focused State Estimator & SCED Input Dates ERCOT is asking that only during these windows each QSE submit a COP such that we can quickly evaluate expectations on Energy Offer Curves and OS’s. Please have these COP’s submitted prior to each trade date in the specified windows.

8. Lead from the front Texas Nodal http://nodal.ercot.com 8 Focused SE & System Constrained Economic Dispatch Testing (SCED) Key Actions –Attend the Focused Input Test II Web Ex October 7, 2008 10am – 12pm –Complete the Test Form http://nodal.ercot.com/readiness/eds3/documents/index.html

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

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 Detail on EIS 1.17 DAM AS InsufficiencyReport notification. –5.3.15 – Asynchronous notifications –4.3.48 – “get” - MarketInfo - AS InsufficiencyReport Alerts / Notifications –MMS System generated Alerts –EMS System generated Alerts –Manually generated Alerts Dispute –Attachment/document compression : If a Dispute Attachment warrants being compressed (i.e. >1MB) it should be done by compressing the entire Dispute XML. The resulting compressed string will be placed in the Payload.Compressed element in the request. The Dispute.Attachment.document should not be compressed. –Added Dispute Types, Sub-Types, and Charge Types cross reference table – figure 212 – Enumerated in the XSDs –Removed VDI from Resource Parameters (Sec 10.3.4) and added it as an independent container/noun in Section 12. Get - An mRID should be manually constructed and used in the Message Request - in the following format 1.QSEID.VDI. 2.QSEID.VDI -- Gets all Change to “Acknowledge” - all properties for the VDI must be specified. Once a VDI is acknowledged, the queries will no longer return that VDI. If all the VDIs have been acknowledged, the query will not return anything.

11. Lead from the front Texas Nodal http://nodal.ercot.com 11 Detail on EIS 1.17 Three more MarketInfo retrievals: –4.3.46 – MarketInfo - AS Obligations –4.3.47 – MarketInfo – Startup/Shutdown Instr. –4.3.48 – MarketInfo - AS InsufficiencyReport 3.3.2 figure 20 – tagged SuMeFipFop as optional Ad-Hoc Query to get Outage –If startTime and endTime are not specified, only active outages will be returned. –startTime and endTime are optional but they should not be present when an mRID is sent. –The mRID can be used to request details of a specific outage. –The GroupID can be used to request outages that are part of a group. –For Ad-Hoc Outage queries, OutageQuery (a container element for querying outages) can be included in the payload with select query elements populated.

12. Lead from the front Texas Nodal http://nodal.ercot.com 12 API Sub-Group Topics General Discussion