1 Nodal Stabilization Market Call December 06, :30 AM

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 General Updates / Reminders

General Reminders / Updates Based on feedback, ERCOT will continue daily Market Calls through the end of December –Daily calls will be held once / daily at 4:30 PM Monday through Thursday starting on 12/8 –Friday calls will continue to be held at 9:00 AM –No calls will be scheduled on the weekend –ERCOT will hold the last 10:30 AM market call on Tuesday 12/7 – These calls will be focused on issues and MP questions (detailed market analysis will no longer be on the agenda starting on 12/8) –ERCOT.com Calendar to be updated with meeting information 4

General Reminders / Updates Weekend Issues 48 hour Disclosure Reports were posted late due to significantly long run times –Friday, December 3rd – Saturday, December 4th –Both days of postings were available for download on Saturday, December 4 th Some 48 hour Disclosure Reports first run dates required by Protocols will be delayed until late December Both lists are available at the end of this presentation 5

6 Day Ahead Market

DAM Operating Day December 4 7

DAM Operating Day December This is the net additional usage of transmission capacity by CRR/PTPs.

DAM Operating Day December 4 9

DAM Operating Day December 4 Top 5 unique binding constraints (based on shadow price) 10

DAM Operating Day December

DAM Operating Day December

DAM Operating Day December

DAM Operating Day December 5 Top 5 unique binding constraints (based on shadow price) 14

DAM Operating Day December

DAM Operating Day December

DAM Operating Day December

DAM Operating Day December 6 Top 5 unique binding constraints (based on shadow price) 18

Price Correction for DAM Operating Day Dec 4 Price Validation Tool identified issue with DAM SPPs on OD Dec 4 th for 2 resource nodes: –Root cause identified –Gap in shift factors during price calculation only (post solution process) –Program fix identified, with interim flagging of issue to identify issue prior to publishing results Communications –Notification sent in MIS this morning –Corrected prices posted at –ERCOT will send broader market notice with detailed information 19

Price Correction for DAM Operating Day Dec

Price Correction for DAM Operating Day Dec

Price Correction for DAM Operating Day Dec DELIVERY_DATEDELIVERY_HOURSTL_PNT_NAMEOriginal_SPPCorrected_SPP 12/4/201018CHE_LYD /4/201019CHE_LYD /4/201020CHE_LYD /4/201021CHE_LYD /4/201022CHE_LYD /4/201018CHE_LYD /4/201019CHE_LYD /4/201020CHE_LYD /4/201021CHE_LYD /4/201022CHE_LYD

23 Real Time Market / LFC

Real Time Market Update 24

Real Time Market Update 25

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Real Time Market Update 27

Real Time Market Update 28

Real Time Market Update 29

30 DRUC  Execution Time = 8 minutes  1 resource commitment  No resource de-commitment  2 unique binding constraints; no constraint violation  DI_DWHI8 : RINCON_WHITE_2_1 (HE1-6, HE8-18)  SGLDSUN8 : 6215__A (HE8)

31  Average Execution time = 10 min (max = 19 min at 12/4 9:03:01 PM)  No resource commitment  No resource de-commitment  2 unique binding constraints; no constraint violation  DI_DWHI8 : RINCON_WHITE_2_1(HE1-24)  SGLDSUN8 : 6215__A(HE3-8) HRUC

Real Time Market Update 32

Real Time Market Update 33

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Real Time Market Update 35

Real Time Market Update 36

Real Time Market Update 37

38 Execution Time = 6 minutes 1 resource manual commitment No resource de-commitment 4 unique binding/violated constraints SALAN_S8 : AIRLIN_CABANI1_1binding (HE21-24) SFORGIL8 : GILLES_8AT1binding (HE8) SGLDSUN8 : 6215__Abinding (HE7-8) SNCWMOS8 : ODNTH_FMR1binding (HE 7-9, 23) violated (HE 10-16) DRUC 12/5

39 HRUC 12/5 Average Execution time = 12 min (max = 19 min at 12/4/2010 9:03:01 PM) 6 resource commitments No resource de-commitment 7 unique binding/violated constraints SALAN_S8 : AIRLIN_CABANI1_1 SFORGIL8 : GILLES_8AT1 SGLDSUN8 : 6215__A SNCWMOS8 : ODNTH_FMR1 SPZGN8 : GT_MID90_A XMGS58 : MGSES_MR2H XMGS58 : MGSES_MR2L

40 Settlements and Billing

Day-Ahead Market Settlement Statements & Invoice Posting Dates –DAM OD 12/01 posted on Friday 12/3 –DAM OD 12/02 posted today Monday 12/6 –DAM OD 12/03 – 12/05 will post tomorrow 12/7 Reminder: QSE’s who intend to Shadow Settle must subscribe to extracts. 41

42 Questions?

48 hour Disclosure Reports Now Available on MIS 43

48 hour Disclosure Reports first run dates required by Protocols will be delayed until late December