1 Market Trials Congestion Revenue Rights Weekly Update May 28, 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 –Credit Constraints 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 this coming week Unplanned Outages There were no unplanned CRR outages this week

Known Issues No know issues

7 Standing Reports and Updates: General reminders / updates Next week’s activities Today –ERCOT will post July Network Model –ERCOT will evaluate whether to run a July “true-up” allocation (we will) Monday –Memorial Day Before Friday –ERCOT will run the July “true-up” allocation Friday –ERCOT will post the July Auction Notice –Counter-parties can begin assigning credit to July 2010 Auction Not removed from ACL until Monday, June 14 th (Credit Lock Day)

8 Q&A FAQ/Follow Up

Q) Last week on the market call, you mentioned that NOIEs will need to resubmit their information to Legal to ensure they meet requirements. What is the deadline for this submission A) Still developing, tentatively due in the middle of July. 9

Q) D I need to create a different Bid ID for every CRR I want to sell in an auction? How do I do so? A) You would not create a Bid ID number- it is generated by the system. You would use the existing CRR ID as the Bid ID in the auction portfolio upload. You would get this from the Downloads tab, by downloading your existing CRRs under Private>Existing CRRs 10

Q) I understand the calculation for determining the credit necessary for a CRR bid is the awarded option MW multiplied by bid price and TOU hours. When we do that calculation we get roughly $1.5M. I don’t see that amount showing up on any of our credit reports. I’m assuming the $1.5M is the amount of credit needed just during the credit lock and then as soon as the CRR’s clear the cleared $ amount is then used in the TPE calculation based on what will be invoiced for that auction. Is that a correct assumption and can you elaborate a little. A) The credit consumed by the CRR auction is exactly the credit assigned to the CRR market in the counterparty screen. That credit also becomes a constraint in the auction. That is, just as the auction algorithm will make sure that the awarded CRRs don't overload any lines, they will also make sure that the awarded CRRs don't go over your allocated credit (based on bid prices). In the example you mentioned, assigning $1.5M would ensure that credit would not reduce your awards. The credit assigned in the counterparty screen is what is taken out of your ACL until invoices are published. At that time the invoiced amount will be taken out instead. 11

Q) It seems that most (but Not All!) Generator and Load data (Pmin, Pmax, etc) is missing from the CRR network model.raw files for monthly auctions. This data is usually considered public, so I don't know why this is being redacted. Can you either let me know when the data will return or tell me why it is being redacted? A) We started redacting most of the generator and load data in late December as a preliminary response to the data redaction NPRR. Tentatively this is our plan going forward. I would like to note that the CRR application does *NOT* use generation or load, nor should any shadowing on your part, so we are posting complete CRR information. We are investigating as to whether we can put this information back in the model going forward. 12

13 Q&A Q&A / Open Forum