Market Trials Open Market Participant Call Weekly Kick Off November 22, 2010 http://nodal.ercot.com 1

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. http://nodal.ercot.com 2

This Week’s Activities – Soft Launch – 9 Days Until Go-Live RTM / LFC Submissions representative of a post go-live scenario Detailed Discussion on generation cutover on Wednesday 10:30 AM meeting DAM / RUC DAM will run daily based on protocol timelines DRUC run daily Results based on unrealistic COPs versus actual resource availability HRUC run hourly SASM will run if necessary High Regulation Prices (Saturday / Sunday) Due to AS Insufficiency as a result of very low participation 52 QSEs Participating on Saturday and 49 QSEs Participating on Sunday Late Publication on Saturday (2pm) REMINDER: COPs are required for post go-live dates (7 days) starting on 11/24/2010 CRR - LIVE 11/22/2010 – Payments to CRRAH 11/24/2010 – Open Credit window for January 2011 Monthly Auction Outage Scheduler - LIVE Realistic outages for effective operational dates post Go-Live Dual entry for 12/1/2010 http://nodal.ercot.com 3

General Reminders Twice Daily Market Calls begin tomorrow 11/23/2010 10:30 AM morning call 4:30 PM afternoon call Details are posted on the ERCOT Calendar website: http://www.ercot.com/committees/nodal/mt/ http://nodal.ercot.com 4

Real Time Market Update 11/18 – 11/21 System Lambda at $180 offer cap for 246 intervals 11/18 – 11/21 System Lambda above $180 for 114 intervals http://nodal.ercot.com 5

Real Time Market Update SCED intervals not at offer cap or higher typically between $20 and $40 11/18 – 11/21 Three constraints; only W_TO_N was ever binding for a short period of time on 11/17 BASE CASE - W_TO_N – active 11/19 – 11/21; binding on 11/20 DGRSLNC5 6380_D_1 – never binding SSPUASP8 MATA_PADR1_1 – binding 11/21 after 8 pm http://nodal.ercot.com 6

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