Lead from the front Texas Nodal 1 EDS 3 Release 5 Monday / Friday Market Updates November 16, 2007

Lead from the front Texas Nodal 2 Agenda Antitrust Admonition Roll Call Submissions Update –Submissions Status –Submission Window for Week of 11/19/07 (holiday week) Updates / Questions / Reminders Known Issues Update EDS 5.3 Activities and Timeline Q&A / Open Forum

Lead from the front Texas Nodal 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.

Lead from the front Texas Nodal 4 Submissions Status Weekends are still low on submissions 90-95% submissions compliance current average Monday - Thursday This week’s missing submissions are largely due to validation errors –Please check your notifications –If you do not have your listener configured, verify submissions using the MMS UI –Do not change any data in your TPO’s (note after holiday, we will be running daily verification on offer curve baseline). 11/8/200711/9/200711/10/200711/11/200711/12/200711/13/200711/14/ % 88%95%78%88%74%83%90%94%91%93%95% COPTPOCOPTPOCOPTPOCOPTPOCOPTPOCOPTPOCOPTPO

Lead from the front Texas Nodal 5 Submission Window for Week of 11/19/07 Activities for Week of 11/19/07 –11/19 and 11/20 Continue to submit TPO and COP for the next trade date during the 12pm – 4pm submission window Continue to make RT adjustments to COP during business hours –11/21 Submit COP / TPO for 11/22 – 11/26 Make RT adjustments to COP during normal business hours –11/22 – 11/26 Non-Business Days – No Submissions Note – you may optionally submit 11/21 – 11/26 dates on Tuesday 11/20.

Lead from the front Texas Nodal 6 Updates / Questions / Reminders Changes to Ports for MIS/MUI and EWS: Proposal: Currently users access MIS/MUI and EWS as follows: MIS : MUI : EWS: This proposal changes these to: MIS : MUI : EWS: Note: EWS will still remain an SSL site.

Lead from the front Texas Nodal 7 Updates / Questions / Reminders Reason for Proposed Change –Non-standard port required custom firewall changes in some cases –Using a specific port in the URL was undesirable from a user standpoint Feedback on Change was Generally Neutral Questions to Consider –Will this still require a change to the available ports from the application server (application to the internet using port 80)? –Will this require an additional change from corporate access (user to the internet using port 443)?

Lead from the front Texas Nodal 8 Updates / Questions / Reminders Next Week’s Market Calls Canceled for Holidays Issues were Encountered with EDS EIP Release Scheduled for Migration 11/27 –Defects found are being addressed –ERCOT will communicate the new release date after the holiday –This is the 1.04 to EDS Release as well as defect fixes Reminder – EDS will go down this evening at 5pm –Ensure submissions for Monday are submitted with today’s testing window –Submitting for Sat / Sun is not necessary –EDS environment will return to service 8am Monday morning

Lead from the front Texas Nodal 9 Issues Update Known Issues Update NOTE: Updated Known Issues will Publish Tonight with Weekly Report on Readiness Center Submitting Partial OS w/o Energy Offer Curve in Place –Will be changed to a warning. Being reviewed for inclusion in Jan 08’s MMS release. GMT Offset Validation –Currently not validated. Will be included in next EIP release OS Time Issues (e.g. not canceling first hour, not creating 24 th hour, etc) –Included in next EIP release Not Populated in Sync Response –Included in next EIP release

Lead from the front Texas Nodal 10 EDS 5.3 Activities and Timeline * TPO 2 hour Next Day Adjustments –Specified QSE’s can move offer curves for a pre-defined 2 hour period on the next day – Each QSE will have an opportunity to adjust * Open TPO –QSE’s may submit any curve during this 5 day period * *

Lead from the front Texas Nodal 11 Q&A Q&A / Open Forum