1. http://nodal.ercot.com 1 Market Trials Open Market Participant Call Weekly Kick Off March 01, 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 This Week’s Activities Market Submission Qualification –ERCOT will continue to work with unqualified QSEs and CRRAH RTM / LFC –6 Month LMP starts today! –Telemetry focus is on quality –Submit Energy Offer Curves (day +2 to avoid phase 2 validations) 80-120% of cost –FIP / FOP – is now the QSE’s responsibility to obtain; ERCOT is updating actual prices daily –ERCOT will continue to schedule individual LFC CRR –April Monthly Auction Notice is now posted –April Monthly Auction bidding opens in one week 3/8/2010 –April Monthly Auction will run on 3/12/2010 Outage Scheduler –43 / 86 QSEs qualified –5 / 20 TSPs qualified –ERCOT will continue to work with QSEs and TSPs on qualification this week Reminder: ERCOT will be performing an extensive release on 3/5/2010. Consequently, the Nodal Production Environment will be unavailable starting at 6pm on Thursday 3/4/2010.

4. http://nodal.ercot.com 4 Follow-ups from last week’s market calls RTM / LFC Call –Do RMR units have any requirements for the Individual generator LFC Tests? A: The only cases where RMR units are required to test are if a QSE only has RMR units and they did not participate in the 2008 LFC testing. –Why were there missing intervals for LMPs on 2/25? A: We have verified that SCED did run for all intervals on the 25 th and sent LMPs over telemetry. We are researching why these did not publish on the MIS. CRR Call –Source / Sink sign clarification A: Source - Sink Daylight Savings question: –Several MPs have asked about Daylight Savings and how we intend to test the short day on 3/14 ERCOT intends to support submission testing only MPs may begin submitting transactions for the short day on 3/7/2010 and ERCOT will answer questions regarding these submittals ERCOT will not be running any DAM, RUC or SASM in the Nodal Production environment on DST

5. http://nodal.ercot.com 5 Follow-ups from last week’s market calls Daylight Savings Short Day Example: Hourly example: 2010-03-14T00:00:00-06:00 2010-03-14T01:00:00-06:00 2010-03-14T03:00:00-05:00 Note: skipped HE 2 and GMT offset change 2010-03-14T03:00:00-05:00 2010-03-14T04:00:00-05:00 15 Minute Example: 2010-03-14T01:00:00-06:00 2010-03-14T01:15:00-06:00 2010-03-14T01:30:00-06:00 2010-03-14T01:45:00-06:00 2010-03-14T01:45:00-06:00 Note: skipped HE 2 and GMT 2010-03-14T03:00:00-05:00 offset change 2010-03-14T03:00:00-05:00 2010-03-14T03:15:00-05:00

6. http://nodal.ercot.com 6 Obtaining LMPs Reminder that Real-time LMPs and SPPs are currently available – produced from SCED running in the market trials environment –MIS (requires a digital certificate) https://mis.ercot.com/pps/tibco/mis Under Real-Time Markets (see next slide for screenshot) –Web services query Section 4.3.11, Market LMPs and SPPs of the External Interfaces Specification located at http://nodal.ercot.com/readiness/sandbox/index.htmlhttp://nodal.ercot.com/readiness/sandbox/index.html –ICCP for QSEs with Resources – Resource LMPs Day-Ahead SPPs and LMPs will not be available until April 1 –Will be available via MIS and the same web services query

7. 2 1 3

9. Real-Time LMP and SPP Postings NDSML http://nodal.ercot.com/re adiness/reports/index.ht ml MIS https://mis.ercot.com/pps/tibco/mis Webservice LMPs by Resource Node (every 5 mins for ~550 resource nodes) also via ICCP with basepoint NP6-787-CD LMPs by Resource Node and Electrical Bus Section 4.3.11, Market LMPs and SPPs of the External Interfaces Specification located at http://nodal.ercot.co m/readiness/sandbox/ index.html (only Real- Time currently Avail) http://nodal.ercot.co m/readiness/sandbox/ index.html LMPs by Electrical Bus (every 5 mins for ~5,000 electrical busses) NP6-787-CD LMPs by Resource Node and Electrical Bus SPPs for Resource Nodes, Load Zones, Hubs (every 15-mins for ~600 Settlement Points) NP6-905-CDSettlement Point Prices at Hubs and Load Zones