1. http://nodal.ercot.com 1 Nodal Stabilization Market Call December 07, 2010 10:30 AM

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 Day Ahead Market

4. DAM Operating Day December 7 http://nodal.ercot.com 4

5. DAM Operating Day December 7 http://nodal.ercot.com 5

6. DAM Operating Day December 7 http://nodal.ercot.com 6

7. DAM Operating Day December 7 Top 5 unique binding constraints (based on shadow price) http://nodal.ercot.com 7

8. http://nodal.ercot.com 8 Real Time Market / LFC

9. Real Time Market Update http://nodal.ercot.com 9

10. Real Time Market Update http://nodal.ercot.com 10

11. http://nodal.ercot.com 11

12. Real Time Market Update http://nodal.ercot.com 12

13. Real Time Market Update http://nodal.ercot.com 13

14. Real Time Market Update http://nodal.ercot.com 14

15. http://nodal.ercot.com 15 No resource commitment No resource de-commitment 7 unique binding/violated constraints DWAP_OB5 : GT_MID90_Abinding for (HE5-6, HE20-24) DWTRTRC5 : TRSES_MR6Lbinding for (HE8-9) SALAN_S8 : AIRLIN_CABANI1_1binding for (HE1-6, 10-24) SCOLPAW5 : COLETO_VICTOR2_1binding for (HE23) SNCWMOS8 : 6915__A violated for (HE7-8, 10-13) SNCWMOS8 : ODNTH_FMR1 binding for (HE2,4,22) violated for (HE3, 5-21) XCAG58 : M3_G2_1binding for (HE20-21) Execution Time = 21 minutes DRUC 12/6

16. http://nodal.ercot.com 16 HRUC 12/6 Average Execution time = 10 minutes (max execution time = 15 min) 6 unique resource commitment No resource de-commitment 10 unique binding/violated constraints DKOCNUE8 : AIR_LI_HIWAY_1_1binding (HE4-5) DWAP_OB5 : GT_MID90_Abinding (HE24) DWTRTRC5 : TRSES_MR6Lbinding (HE8-11,19) SALAN_S8 : AIRLIN_CABANI1_1binding (HE1-24) SNCWMOS8 : 6915__Aviolated (HE6-13,15,19) SNCWMOS8 : ODNTH_FMR1binding (HE1-2,23-34); violated (HE3- 22) XCAG58 : M3_G2_1binding (HE9, 19-22) XMGS58 : MGSES_MR2Hbinding (HE2, 4-6, 7,9) XMGS58 : MGSES_MR2Lbinding (HE2, 4-6, 7,9) XN_S58 : AIRLIN_CABANI1_1binding (HE10)

17. http://nodal.ercot.com 17 SASM 12/6 - 12/6 hr ending 19-21 for ~50MW of RRS insufficiency - MCPC = $4.00

18. http://nodal.ercot.com 18 Credit

19. Treasury Upcoming Nodal invoice payments due: –DAM for OD December 1 st – due December 8 –DAM for OD December 2 nd – due December 9 –DAM for OD December 3 rd – due December 10 –DAM for OD December 4 th – due December 10 –DAM for OD December 5 th – due December 10 To ensure timely posting of payments received (particularly if combining multiple invoices in one wire) –include the invoice numbers for all invoices being paid on a wire On a due date, if an invoice payment has not been received, ERCOT plans to send out an e-mail reminder to QSE/CRRAH authorized rep and back up CP authorized rep and back up Credit contact and back up Note: Please be sure that ERCOT has updated contact information for your company – notices will be an automated process and will use the information in ERCOT’s Registration System. http://nodal.ercot.com 19

20. Treasury Collateral and invoice payments received are posted same day –Collateral and invoice payments received before 12:00 noon will be included for the ACL available for the next day’s DAM (e.g. received by noon Monday will be reflected in Tuesday’s DAM ACL) –Collateral and invoice payments received after 12:00 noon will be included for the next day’s Credit Reports and the following day’s ACL (e.g. received after noon Monday will be reflected in Wednesday’s DAM ACL) Collateral reimbursement requests will generally be processed the next business day –Beginning December 1, refunds of collateral will be principal only (interest will not be included) –Interest will be paid semi-annually rather than in conjunction with each collateral refund http://nodal.ercot.com 20

21. http://nodal.ercot.com 21 Questions?