October, 2009 Congestion Report Isabel Flores

2 October, 2009 Background Provide trend of local congestion costs for last 13 months Costs shown in millions Volume shown in thousands of MWhs –OOMC –OOM Down –LBE Down –OOM Up –LBE Up –RPRS Top congested elements Inter-zonal costs

3 October, 2009 OOMC 2008 vs $M Million$SouthNorthHoustonWest

4 October, 2009 OOM Down - $M Million$SouthNorthHoustonWest

5 October, 2009 OOM Down - MWhs MWhs (thousands) SouthNorthHoustonWest ,555.78

6 October, 2009 Balancing Energy Down - $M Million$SouthNorthHoustonWest

7 October, 2009 Balancing Energy Down - MWhs MWhs (thousands) SouthNorthHoustonWest

8 October, 2009 OOM Up - $M Million$SouthNorthHoustonWest

9 October, 2009 OOM Up - MWhs MWhs (thousands) SouthNorthHoustonWest

10 October, 2009 Balancing Energy Up - $M Million$SouthNorthHoustonWest

11 October, 2009 Balancing Energy Up - MWhs MWhs (thousands) SouthNorthHoustonWest

12 October, 2009 OOME & Wind Capacity

13 October, 2009 Average MCPE

14 October, 2009 Replacement Reserve 2008 vs Thousand $ JanFebMarAprMayJunJulAugSepOctNovDectotal

15 October, 2009 Inter-zonal Congestion Charges Million$N_HN_SS_NW_NN_W (18.3) (7.69) Settlement quality, net dollars.

16 October, 2009 Top Congested Elements Following slides provide top congested elements for 2009 by month Amounts shown are estimates, not settlement quality dollars

17 October, 2009 Top Overloaded Elements - September ContingencyBinding ElementEst.CostsTransmission Project Oak Creek – Ballinger 138kVMiles – Rowena 69kV$2,547,232 Yellow Jacket Phase Shifting Transformer addition (08TPIT0135) Capacity Shortage$1,622,568 Oak Creek – Ballinger 138kV Abilene South – Ballinger 69kV$819,234 Ballinger to Abilene South 69kV, rebuild (08TPIT0080) Temple Pecan Creek - Tradinghouse & Temple Switch - Lake Creek SES San Angelo Power Station - Shrew Tap$370,342 Yellow Jacket Phase Shifting Transformer addition (08TPIT0135) Garfield - Onion Creek & Hicross AEN 138kV Lytton Springs 345/138kV Autotransformer #4$338,471 Lytton Springs Autotransformer, addition (10TPIT0058) Tradinghouse SES - Venus Switch 345kV Rogers Hill TU - Elm Mott 138kV$327,011 Elm Mott – Waco Northcrest 138kV, upgrade (10TPIT0091) Dilley Switch - San Miguel 138kVDerby - Pearsall 69kV$199,939 Pearsall to Dilley 69 kV Line Upgrade (09TPIT0189) Everman Switch - Sherry Switch 345kV Everman Switch - Oak Hill 2 Tap 138kV$129,597 Hillje - Holman 345kV Columbus - Stafford Hill 69kV$79,526 North Denton 138/69kV Autotransformer $69,064

18 October, 2009 Top Overloaded Elements - August ContingencyBinding ElementEstimated Costs Transmission Project Capacity Shortage$4,554,174 Temple Pecan Creek - Tradinghouse & Temple Switch - Lake Creek SES San Angelo Power Station - Shrew Tap$3,702,120 San Angelo Power Station, to Menard 138 kV line improvements (09TPIT0212) Watermill - West Levee SW & Sargent RoadWatermill – DeSoto$1,545,708 Trinidad – Watermill 345kV line (07TPIT0140) Dilley Switch - San Miguel 138kVDerby - Pearsall 69kV$473,910 Pearsall to Dilley 69 kV Line Upgrade (09TPIT0189) Watermill – Tricorner & Trinidad 345kVWatermill – DeSoto$390,506 Trinidad – Watermill 345kV line (07TPIT0140) North Denton 138/69kV Autotransformer $233,598 Austrop – Daffin & Decker 138kVAustrop –Decker 138kV$221,789 Decker to Techridge 138kV Relocation (07TPIT0050) OutagesZorrillo Planned Outage$175,321 W_N Stability $59,422

19 October, 2009 Top Overloaded Elements - July ContingencyBinding ElementEstimated CostsTransmission Project Capacity Shortage$4,159,576 Temple Pecan Creek - Tradinghouse & Temple Switch - Lake Creek SES San Angelo Power Station -Shrew Tap$3,349,357 San Angelo Power Station, to Menard 138 kV line improvements (09TPIT0212) Maintenance$954,856 Watermill - West Levee SW & Sargent RoadNorwood Autotransformer$723,839 Trinidad – Watermill 345kV line (07TPIT0140) RPRS$598,365 Dilley Switch - San Miguel 138kV Derby - Pearsall 69kV$345,245 Pearsall to Dilley 69 kV Line Upgrade Bates - Pearsall 138kV (09TPIT0189) Laredo Import$273,432 North Denton 138/69kV Autotransformer $183,699 Jewett - Big Brown 345kVBig Brown Sw$174,798 Jewett - Big Brown 345kV upgrade (09TPIT0082) Hillcountry - Marion & Elm Creek 345kVSchertz - Parkway 138kV$167,019 Parkway-Schertz build new 138kV line (10TPIT0064)

20 October, 2009 Top Overloaded Elements - June ContingencyBinding ElementEst.CostsTransmission Project Menard - Gillespie 138kVMenard Auto$3,620, Yellowjacket, Add Phase Shifting transformer (08TPIT0135) Skyline to Marion & Elm Creek 345Marion - Hill Country 345kV$3,159, Hill Country to Skyline kV 2nd Circuit (09TPIT0012) Temple Pecan Creek - Tradinghouse & Temple Switch - Long Creek SES San Angelo Power Station - Shrew Tap$2,923, San Angelo Power Station, to Menard 138 kV line improvements (09TPIT0212) Capacity Shortage$2,545, Watermill - West Levee SW & Sargent RoadWatermill - DeSoto$1,832, Trinidad – Watermill 345kV line (07TPIT0140) Watermill - DeSoto Switch - Cedar Hill Switch 345kVWatermill - DeSoto$1,582, Trinidad – Watermill 345kV line (07TPIT0140) Oklaunion - Fisher Road - Bowman 345kVVernon - Grayback 69kV$891, Fisher Road - Wichita Falls 138 kV line upgrade (09TPIT0118) Tradinghouse - Venus Switch 345kVRogers Hill - Elm Mott 138kV$839, Elm Mott - Waco Northcrest 138 kV line upgrade (10TPIT0091)N. Waco - NE. Waco 138 kV line upgrade (09TPIT0047) Dilley Switch - San Miguel 138kVDerby - Pearsall 69kV$704, Pearsall to Dilley 69 kV Line Upgrade (09TPIT0189) Tradinghouse - Venus Switch 345kV Rogers Hill - Bosque Switch 138kV$513, Elm Mott - Waco Northcrest 138 kV line upgrade (10TPIT0091) N. Waco - NE. Waco 138 kV line upgrade (09TPIT0047)

21 October, 2009 Top Overloaded Elements - May ContingencyBinding ElementEst.CostsTransmission Project Comanche Peak SES - DeCordova SES & Wolf Hollow - Rocky Creek 345kV Venus Switch - Comanche Peak 345kV $3,515,768.74Venus - Cedar Hill 345 kV line upgrade Watermill - DeSoto Switch - Cedar Hill Switch 345kV Watermill - DeSoto$1,966,940.07Trinidad – Watermill 345kV line Comanche Peak SES- DeCordova SES & Wolf Hollow-Rocky Creek 345kV Comanche Peak SES - Parker Switch 345KV $1,652,826.07Willow Creek - Parker 345 kV line rebuild as double circuit Capacity Shortage $1,613, Comanche Peak SES- DeCordova SES-Wolf Hollow 345kV Parker Switch - Benbrook Switch 345KV $1,160,067.25Parker Switch - Everman 345 kV line Comanche Peak SES- DeCordova SES & Wolf Hollow-Rocky Creek 345kV Venus Switch - Johnson Switch TU 345kV $744,535.01Venus - Cedar Hill 345 kV line upgrade Valley Import $732, Replacement Reserve Service $444,068.87

22 October, 2009 Top Overloaded Elements - April ContingencyOverloaded ElementEst. Cost Ballinger - Santa Anna 138kVBallinger - Humble 69kV$ 6,438, Area Security - Valley$ 1,718, Lytton S/HC TapAustrop outage$ 948, Parkdale Switch - Prairie Creek 138kVPrairie Creek – Prairie Creek Switch$ 649, Capacity Shortages$ 470, Valley Import$ 466, South Abilene - Eskota 138kVTrent - Merkel 69kV$ 466, Morgan Creek SES - Odess EHV & Quail Switch 345kV Big Spring Switch - Big Spring West 138kV $ Austrop 345/138kV Autotransformer T1/T2Austrop 345/138kV Autotransformer T2/T1 $ 401, Multiple DFW area outages Lon Hill - Pawnee outage Elkton-Fowsaw outage Outages$ 368,054.91

23 October, 2009 Top Overloaded Elements - March ContingencyOverloaded ElementEst. Cost Comanche Peak SES - DeCordova SES & Wolf Hollow - Rocky Creek 345kV Concord 345/138kV Autotransformer$ 3,618,654 Ballinger – San Angelo Red Creek 138kVMiles – Rowena 69kV$ 3,074,447 Valley Import$ 2,579,227 Ballinger-Santa Anna 138kVBallinger-Humble 69kV$ 2,075,244 Austrop-Lost Pines 345kVWinchester-Fayetteville 138kV$ 895,574 Roanoke Switch-West Denton & Lewisville Switch 345kV West Denton-Airport 138kV$ 872,109 Lon Hill-Coleto Creek 345kVWarburton-Victoria 138kV$ 784,143 TRESES-Entpr XAus58T2 Jewett-Tomball Lon Hill-Pawnee Outages$ 774,483 Capacity Shortages$ 534,124 West to North Stability$ 511,961

24 October, 2009 Top Overloaded Elements - February ContingencyOverloaded Element Basecase Graham SES-Long Creek 345kV Sandow Switch-Austrop 345kV SAPS - Menard 138kV$ 12,006, Valley Import$ 2,522, Watermill Swithch - DeSoto Switch-Cedar Hill Switch West Levee Auto$ 914, King-Kuykendahl-Roans Prairie & Jewett- Tomball 345kV Oasis-PH Robinson 345kV Garrott - Midtown 138kV$ 730, Garfield 345/138 Auto 1Garfield 345/138 Auto 2$ 656, Capacity Shortages$ 557, Gail 138kV Marion-Elm Crk McDonald-Forsan Aspermont-Spur Outages$ 519, Temple Pecan Creek - Trading House$ 383, Austrop 345/138kV Autotransformer T1/T2Austrop 345/138kV Autotransformer T2/T1$ 302, West to North Stability$ 255,350.93