Cutover Market Call November 29, 2010 4:30 PM 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

General Updates / Reminders http://nodal.ercot.com 3

Cut-Over Update – Go-Live Sequence of Events Action Comments 11/15/2010 – 11/29/2010 ERCOT Initiates “Soft Launch” to Nodal Market Go-Live ERCOT will run non-binding DAM, RUC daily per Nodal protocol timelines. RTM will remain Open Loop, but continue to publish base points and LMPs. Note that credit will be set high on 11/15 11/15/2010 Credit posts ACLs and TPEs for non-binding DAM For Operating Day 11/15 credit will be manually set to high limits 11/16/2010 First Credit Operating Day 11/16 Credit reflects actual limits 11/17/2010 Market now able to submit transactions for first Nodal Operating Day (T-14d) 12/01 Operating Day open for Market submissions 11/24/2010 QSEs with Resources required to submit 7 days of rolling COPs 12/01 required on 11/23 11/28/2010 2:00 PM – 11/28/2010 3:00 PM Generation and Frequency Control switched to Nodal systems for final LFC test QSEs will begin following Nodal base points Settlements will continue to be Zonal 11/30/2010 11:59:59 PM QSEs remain on Nodal Control while settling Zonally during the LFC test 11/29/2010 Last Non- Binding DAM for operating day 11/30 http://nodal.ercot.com 4

Cut-Over Update – Go-Live Sequence of Events (11/30/2010) Time Action Comments up to 10:00 Bids and Offer submission  QSE submit bids and offers 10:00 Close DAM   Execute Dam Clearing Process 13:30 Approve DAM results Day Ahead results posted to MIS 13:30-14:30 Submit Post DAM COP updates 14:30 Close for RUC Begin Execution of DRUC 16:00 Approve DRUC Results Post DRUC Results 18:00 HRUC Begins Hourly Runs http://nodal.ercot.com 5

Phase 2 Validation reports and process Special Topics Phase 2 Validation reports and process Phase 2 validation re-evaluates all submitted transactions at 7 am in the day-ahead with updated information, such as AS Obligation, CRR ownership, credit limits, FIP/FOP for TPO caps, etc. If there is a validation error, ERCOT will cancel the transaction ERCOT sends a notice that a Phase 2 report is available for a particular transaction type, and notification containing the cancellation for the transaction. You can query for the Phase 2 report via web services or on the Reports page of the Market Manager in order to view the reason for the cancellation. If applicable, correct and resubmit prior to 10 am Note that submissions are locked out during the Phase 2 process, which starts around 7 am and is currently taking about 5-10 minutes to complete. Error message says that ‘submissions are not allowed during Phase 2 validation’ http://nodal.ercot.com 6

Phase 2 Validation reports and process Special Topics Phase 2 Validation reports and process http://nodal.ercot.com 7

Phase 2 Validation reports and process Special Topics Phase 2 Validation reports and process http://nodal.ercot.com 8

Phase 2 Validation reports and process Special Topics Phase 2 Validation reports and process http://nodal.ercot.com 9

Verifiable Costs Special Topics If you exceed the verifiable cost cap when submitting a TPO, the message returned will indicate the cap value that is in the market system http://nodal.ercot.com 10

FAQ Q: Can I self-commit my resource a partial day and submit startup costs for other hours? A: No. For example, if you attempt to self-commit hours 7-22, but submit startup/min energy offers for hours 1-6, 23-24, the offer is accepted structured this way, but hours 7-22 are not considered self-committed by the DAM and the clearing behavior will reflect a non- self-committed offer. Meaning, if there is no overlap with the LSL/HSL in the COP in the energy offer curve, that makes the energy offer curve invalid for use in the DAM. If there is an online AS Offer for the same resource, the QSE can be awarded energy at LSL in conjunction with the AS Offer. Note that this can cause a QSE to be awarded above the submitted energy offer curve. Q: Can I self-commit my share of a JOU if the other owners submit startup costs? A: No. Similar to the answer above, the energy offer curve will be accepted, but will be invalid for award by DAM if there is no overlap with the HSL/LSL in the COP. If the offer is invalid, the physical resource cannot be awarded. In this scenario, all owners have to self-commit or all owners have to submit full TPOs to be awarded. http://nodal.ercot.com 11

Questions http://nodal.ercot.com 12