1 Market Trials Congestion Revenue Rights Weekly Update June 25, 2010

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 Agenda Anti-trust Admonition Environment Report –Planned / unplanned outages –Known Issues Standing Reports and Updates –Future activities Question and Answers / General Discussion –FAQ ERCOT asks that Market Participants log into the WebEx session using their company name and then their name. This will allow ERCOT to take roll-call offline

Market Trials 2010 Roadmap 4

5 Day-to-day operations summary: Planned / Unplanned Outages of EDS Planned Outages No planned outages Unplanned Outages There were no unplanned CRR outages this week

Known Issues No new known issues

7 Standing Reports and Updates: General reminders / updates Next week’s activities Today, 25 June -- Post CRR Network model for August 2010 Auction -- Allocate 2011/2012 PCRRs Friday, 2 July -- Post CRR Network model for 2011/2012 Annual Auction -- Post Auction Notice for August 2010 Auction

8 Q&A FAQ/Follow Up

I don’t understand/like the A & M factors mentioned in the credit constraint explanation (1) (a) (iii) The additional credit requirement for all awarded PTP Obligations, which is $A per MW per hour, plus the absolute value of the PTP Obligation bid price multiplied by M. The values of A and M Shall be posted on the MIS Public Area. TAC shall review these values at least annually and may recommend, to the ERCOT Board, changes to these values that become effective at least 30 days prior to a monthly CRR Auction and 60 days prior to an annual CRR Auction. Any changes to these values shall be posted on the MIS Public Area within three Business Days of ERCOT Board approval. Currently at A = 1.5$/MWh; M = 1 Will be posted in auction notices going forward. 9

The behavior of 24 Hour bids in the CRR Monthly Auctions 24 hour bids can be entered into CRR Monthly auctions The auction engine treats a 24 hour bid as a single bid across the three time of use network models (Peak WD, Peak WE, Off-peak) –Single MW amount –Single $/MW-hr bid price (not to exceed) If the Bid Price is higher than the weighted (by number of hours) average of the three times of use clearing prices(Peak WD, Peak WE, Off-peak) then the CRR bid will be awarded fully (assuming there is no active budget constraint). If the Bid Price is lower than the weighted average of the three times of use clearing prices then the CRR bid will not be awarded. If the Bid Price is equal to the weighted average of the three times of use clearing prices then the CRR bid will be awarded at some level between 0 and 100%, but the same in each time of use.

24 Hour Example in Monthly Market 24 hour CRR bid for February 2013 Monthly Auction –28 x 8 = 224 Off-peak hours –8 x 16 = 128 PeakWE hours –20 x 16 = 320 PeakWD hours –28 x 24 = 672 total hours For a certain path prices are as follows –Off-peak 2$/MW-hr (arbitrary number for this example) –PeakWE 3$/MW-hr (arbitrary number for this example) –PeakWD 8$/MW-hr (arbitrary number for this example) –24 hour = (224x x x8)/672 = $5.048/MW-hr –Note that a 24 hr bid of $6/MW-hr would be fully awarded in each time of use even though it was less than the clearing price in the PeakWD time of use. –Also note that a 24 hr bid of $4/MW-hr would not be awarded at all, even though it was more than the clearing price in the Off-peak and PeakWE times of use.

The behavior of 24 Hour bids in the CRR Annual Auctions 24 hour bids can be entered into CRR Annual auctions The auction engine treats a 24 hour bid as a short cut for entering three separate bids in the three time of use network models (Peak WD, Peak WE, Off-peak) If the Bid Price is higher than the clearing price in a given time of use (Peak WD, Peak WE, Off-peak) then the CRR bid will be awarded fully in that time of use (assuming there is no active budget constraint). If the Bid Price is lower than the clearing price in a given time of use then the CRR bid will be not be awarded in that time of use. If the Bid Price is equal to the clearing price in a given time of use then the CRR bid will be awarded at some level between 0 and 100% in that time of use.

24 Hour Example in Annual Market 24 hour CRR bid for February 2013 in 2012/2013 Annual Auction For a certain path prices are as follows –Off-peak 2$/MW-hr (arbitrary number for this example) –PeakWE 3$/MW-hr (arbitrary number for this example) –PeakWD 8$/MW-hr (arbitrary number for this example) –Note that a 24 hr bid of $6/MW-hr would be fully awarded in PeakWE and Off-peak, but not awarded in PeakWD –Also note that a 24 hr bid of $4/MW-hr would also be fully awarded in PeakWE and Off-peak, but not awarded in PeakWD

14 Q&A Q&A / Open Forum