1. http://nodal.ercot.com 1 Market Trials Congestion Revenue Rights Weekly Update April 30, 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 Agenda Anti-trust Admonition Environment Report –Planned / unplanned outages –Known Issues Standing Reports and Updates –General reminders / updates Qualification Update 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

4. Market Trials 2010 Roadmap http://nodal.ercot.com 4

5. http://nodal.ercot.com 5 Day-to-day operations summary: Planned / Unplanned Outages of EDS Planned Outages –Planned Outages 04/30/2010 11am-5pm –ERCOT will be upgrading the CRR system at this time and it will be unavailable for part or all of this timeframe. Unplanned Outages There were no unplanned CRR outages this week

6. http://nodal.ercot.com 6 Environment Report: Known Issues Reminder: ERCOT will post known issues every Friday to the readiness center at: http://nodal.ercot.com/readiness/markettrials/crr/index.htmlhttp://nodal.ercot.com/readiness/markettrials/crr/index.html New known issues –We did not apply the OBL restrictions to the BOY Auction. We will for the annual. –If a source/sink has different properties in different auctions, a template portfolio containing that bid cannot be saved (as of today) –3 market participants have reported issues manipulating the portfolio editor GUI that ERCOT cannot reproduce. If you have faced odd issues in the portfolio editor and changed something on your side that fixed them, please send an email to Markettrials@ercot.comMarkettrials@ercot.com Closed issues (closed in today’s release) –Invoiced amounts for PCRRs are based upon a rounded per MWh clearing price. –Private Downloads -> Market Results for monthly allocations won’t render –Bilateral Trades allow a 24-hr buy posting

7. http://nodal.ercot.com 7 Standing Reports and Updates: General reminders / updates Next week’s activities –ERCOT posts June 2010 Auction model Monday, 3 May –Balance of Year Market Results posted Wednesday, 5 May (delayed from handbook) –Balance of Year Invoices posted Thursday, 6 May (also delayed) –The Credit for the Balance of Year auction released Thursday 6 May (also delayed) –ERCOT will post the CRR ownership (as of 30 April) on Friday, 7 May –ERCOT posts June 2010 Auction notice on Friday, 7 May –Credit submission window opens for June 2010 Auction on Friday, 7 May Further in the Future –Credit integrates with CRR/DAM on 16 May (more details later) –June Auction window 17-20 May –June Credit Locks 17 May

8. Balance of Year Bid analysis Total bids/offers = 13602 Unique Paths = 463 Unique Products = 3311 Bids = 13595 Offers = 7 24-hours = 240 (all bids) PeakWD = 4850 PeakWE = 4101 Off-peak = 4411 Bid price less than or equal to 0 = 452 OBL = 6790 OPT = 6812 HB/LZ to HB/LZ = 5606 RN to HB/LZ = 4853 HB/LZ to RN = 77 RN to RN = 3066

9. Balance of Year Bid analysis June – Dec = 3479 June = 1460 July = 940 August = 760 September = 1154 October = 1036 November = 634 December = 1460 Other combinations = 2679

10. Qualification Update 65 / 68 CRRAHs are qualified (three CRRAH still in 30 day grace period) Nodal Scorecard will update on 05/05/2010 The CRR Dashboard –The dashboard will be updated every Friday at 7pm http://nodal.ercot.com/readiness/markettrials/crr/index.html http://nodal.ercot.com/readiness/markettrials/crr/index.html http://nodal.ercot.com 10

11. http://nodal.ercot.com 11 Q&A FAQ/Follow Up

12. FAQs Q) I am not able to view our May monthly PCRR Allocation file in CSV format, as posted on the CRR Downloads in Market Result. A)Convert the XML to a CSV by following the steps below: A)Download the file to your desktop as an XML B)Open up a new blank Excel document C)Drag and Drop the file into the blank Excel document D)When the Open XML pop-up window appears asking for you to select how you would like to open the file, select the radio button corresponding to “As an XML table” E)Click OK F)Find and replace all instances of “ns1:” with an empty text field (ie, leave the “Replace With” text field blank) G)Save the file as a CSV.

13. Q) Is there an e-mail list that sends notices about the trial auctions and other related market trial activities? A) Market Transition distribution list is the best one to get on for market trials notices related to CRR. Please contact your Wholesale Client Services Rep to have them get you added. http://nodal.ercot.com 13

14. Q) Will the bid limit for all auctions (monthly and multi-monthly) always be set at 2,000 bids per account holder? A) Starting with the June Monthly auction, bid limit will be increased by 200,000 / [# active market participants]. The number of bids will fluctuate, depending on the number of CRR account holders in the system. http://nodal.ercot.com 14

15. Q) In all multi-month auctions, what is the longest period for which I will be able to enter OBLIGATION bids? A)per Nodal Protocol 7.5.1 (5)(b)(ii), ERCOT will not be accepting PTP Obligation Bids past the first month for all multi-month auctions, until the ERCOT Board approves PTP Obligations for specified source Settlement Points and sink Settlement Points for terms longer than one month. Currently, there are no such Board-approved sources and sinks. http://nodal.ercot.com 15

16. http://nodal.ercot.com 16 Q&A Q&A / Open Forum

17. Appendix http://nodal.ercot.com 17