October 16, 2009 RPG Meeting ERCOT 2009 Five-Year Transmission Plan Update Jeff Billo

2 RPG MeetingOctober 16, Five-Year Transmission Plan: Where we’re at Conditioned Case N-X Analysis G-1 + N-X Analysis TO/ MP Input Reliability Project Backout Reliability AC Case Economic Analysis AC Case with All Upgrades = Complete= In Process= Not Started

3 RPG MeetingOctober 16, Five-Year Transmission Plan Reliability Analysis Two significant project changes since last update –Changed Alliance 345/138-kV autotransformer project to Hicks 345/138-kV autotransformer project –Changed addition of second 345/138-kV autotransformer to Mustang 345-kV station and autotransformer project Miscellaneous reliability project changes since last update based on comments from Transmission Owners

4 RPG MeetingOctober 16, 2009 Hicks 345/138-kV autotransformer project Reliability Issue: One Roanoke 345/138 kV autotransformer overloads for the loss of the other Roanoke 345/138 kV autotransformer in 2013 and 2014 Not feasible to replace both Roanoke autotransformers or add a third autotransformer Additional need to add transmission southwest of Roanoke for load growth needs

5 RPG MeetingOctober 16, 2009 Hicks 345/138-kV autotransformer project Two options studied: 1.Build new 345/138 kV station near Alliance; construct double circuit 138 kV line from new station to new load serving stations to Elizabeth Creek Cost = $21.5M + cost of new 138 kV double circuit 2.Construct a 138 kV bus at the new Hicks CREZ station and install a 345/138 kV autotransformer, construct double circuit 138 kV line from Hicks to new load serving stations to Elizabeth Creek Cost = $11.0 M + cost of new 138 kV double circuit –Length of new 138 kV double circuit roughly the same for both options so cost assumed to be the same Both options tested in 5YTP 2014 economic case with and without CREZ generation –Hicks option resulted in production cost savings of $2.12M in 2014 economic benchmark case –Hicks option resulted in production cost savings of $3.75M in 2014 economic case with CREZ generation –Savings resulted from reduction in congestion on the Hicks-Alliance 345 kV line for the contingency of Hicks-Roanoke 345 kV line Option 2 (Hicks) recommended as preferred option

6 RPG MeetingOctober 16, 2009 Mustang 345 kV station project 2014 Reliability Issues: –Collin 345/138 kV autotransformer overloads for the contingency loss of Collin-Carrollton Northwest 345 kV line –Low voltages on Kruegerville-Frisco 138 kV line for the contingency loss of Collin-Frisco 138 kV line –Existing series reactor at Collin (SPS) does not relieve overload in 2014

7 RPG MeetingOctober 16, 2009 Mustang 345 kV station project Two options studied 1.Add second 345/138 kV autotransformer at Collin, install shunt capacitors on Kruegerville-Frisco line –Existing stations on Kruegerville-Frisco line not sized for capacitor bank additions –Cost ~ $11-12M 2.Create a 345 kV bus at Mustang, loop one circuit the Anna-Krum West 345 kV CREZ line into Mustang, install a 345/138 kV autotransformer at Mustang –Cost ~ $18.5M Other considerations –High load growth area –Mustang option (Option 2) provides support to east side of Denton loop Mitigates the need to reconductor Pockrus-Denton Steam 138-kV line (<$1M) Option 2 recommended as preferred option

8 RPG MeetingOctober 16, Five-Year Transmission Plan Economic Analysis 2014 Economic Projects

9 RPG MeetingOctober 16, Five-Year Transmission Plan Economic Analysis 2014 Changes since August RPG Meeting –Various model corrections and updates (see posted spreadsheet: “2009 5YTP Economics 2014 Project Set xls”) –Changed Horse Hollow 3 to inject into Kendall (via NextEra private 345 kV line) To relieve congestion due to contingency loss of one Bluff Creek 345/138 kV autotransformer overloading the other Bluff Creek autotransformer Not economic to switch more Horse Hollow generation to Kendall due to congestion near Kendall –Ten economic projects: Upgrade the Alvin Tie Sw Station (39015) – Alvin Sub (39030) and the Hastings Sub (39010) – Friendswood Sub (38980) – Seminole Sub (38990) - Magnolia Sub (38950) 138 kV lines from 190/190/190 to 326/326/326 MVA Add a 345/138 kV autotransformer at Panhandle A_D (99104) and rebuild Matador-Spur as a double circuit line with one side operated at 138 kV and the other side operated at 69 kV. Connect McAdoo and Whirlwind to the 345/138 kV autotransformer via 138 kV lines. The 138 kV circuit will not be connected to the load serving system. The 69-kV circuit will be connected only to the load serving system. Add a second circuit to Oasis (43035) – South Alvin (43030), 345 kV Upgrade the 345/138 kV autotransformer at Greens Bayou from 400 to 600 MVA Upgrade the Midland East (1023) – Stanton West (1326) 138 kV line from 84/84/84 to 394/394/394 MVA Build a second Kenedy Switching Station #1 (8184) – Kenedy (8188) 69 kV with a different right of way Upgrade the Round Rock (3668) – Round Rock Northeast (3670) 138 kV line from 214/214/214 to 326/326/326 MVA Upgrade the Seagoville (3076) – Kleberg Tap (3077) 138 kV line from 214/214/214 to 326/326/326 MVA Upgrade the Hidalgo (8963)-Monte Cristo (8708)-Aderhold Substation (8754) 138 kV line to 365/365/365 MVA Add a 1.2-ohm series reactor at the terminal of the South McAllen (8371) – Las Milpas Substation (8758) 138 kV line

10 RPG MeetingOctober 16, Five-Year Transmission Plan 2014 Economic Analysis Select Projects

11 RPG MeetingOctober 16, 2009 Alvin area projects New 345/138 kV station and autotransformer scheduled to be constructed at Meadow (formerly South Alvin) in May 2010 Congestion expected on 138 kV lines exiting Meadow towards the east for contingency loss of Meadow-PH Robinson 345 kV line Congestion expected on Oasis-Meadow-PH Robinson 345 kV line for contingency loss of Cedar Bayou-Chambers/ Cedar Bayou-North Belt 345 kV double circuit and n-0

12 RPG MeetingOctober 16, 2009 Alvin area projects CenterPoint has TPIT project to uprate Oasis-PH Robinson 345 kV line by end of YTP economic recommendations: –Add second circuit to Oasis-Meadow 345 kV line Cost = $4.9M 2014 PC Savings = $2.8M Ratio = 1.75 < 6 –Upgrade Alvin Tie (Meadow)-Alvin and Alvin Tie (Meadow)-Hastings- Friendswood-Seminole-Magnolia Cost = $21.2M 2011 PC Savings = $5.2M Ratio = 4.08 < 6 *Alvin Tie (Meadow)-Hastings 138 kV line upgrade is a reliability project in 2014

13 RPG MeetingOctober 16, 2009 Lower Panhandle Project Congestion on lines exiting the Whirlwind and McAdoo wind generation plants –Daily Operations –5YTP models Whirlwind – 60 MW McAdoo – 150 MW

14 RPG MeetingOctober 16, 2009 Whirlwind Spur Matador Lower Panhandle Project 5YTP Solution – Construct project to separate wind power from load serving system and instead inject to CREZ system Waiting for cost estimates to determine if economic ~ ~ Cottonwood (Pan A-D) McAdoo

15 RPG MeetingOctober 16, YTP Next Steps Finish Analysis by October 30 Report First Draft by November 13

16 RPG MeetingOctober 16, 2009 Questions?