July 13, 2012

Transmission Needs AnalysisScenario 1 Update: BAU All Technologies

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Agenda

• Review Major Process Steps

• Review Base Case Upgrades

• Area Analysis

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Major Process Steps

Base Case Development– Develop a simplified network for study years 2022 (10yr) and

2032(20yr) based upon the most recent 5YP Case– Incorporate scenario-specific economic assumptions

• Load forecast

• Resource development / retirement

– Create a workable case• Identify and alleviate base case overloads

• Update monitored elements

• Identify and review congestion

– Identify Conceptual Projects• Work with TDSP’s to identify plausible solutions / economic

alternatives to Base Case issues

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Major Process Steps

AC Analysis– Identify import limitations to major load regions that maintain

voltage stability– Impose import constraints in a DC Model

Economic and Reliability Assessment– Assess the adequacy of existing infrastructure and supplemental

conceptual projects at meeting study criteria– Document scenario specific results by Area, including

• Significant Issues

• Reliability concerns

• Economic Opportunities

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Base Case Reliability Upgrades 2022

To build a solvable 2022 model, certain upgrades were necessary to replicate what would typically be resolved in shorter term planning horizons. In certain

instances (primarily near major load zones) major upgrades were necessary to build a useable case:

kV MilesApproximate Cost

345 376 $700M (2012)

138 360 $278M (2012)

Including:• One upgrade of an existing 345kV Import into Houston

•Multiple 345kV upgrades with the Houston Urban area

•Several major upgrades of existing 345kV imports into Dallas / Fort Worth from east of the DFW region

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Base Case Reliability Upgrades 2022

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Base Case Reliability Upgrades 2032

Similar to(but more extreme than) the 2022 model, development of a 2032 model required certain upgrades necessary to replicate what would typically be resolved in shorter term planning horizons. In certain instances (primarily near major load

zones) major upgrades were necessary to build a useable case:

kV MilesApproximate Cost

345 1376 $2.1B(2012)

138 360 $1.2B (2012)

Including:• An incremental 345kV Import into Houston

•Extensive 345kV upgrades from South to Houston as well as 345kV upgrades into the Houston Urban area

•Extensive 345kV upgrades of existing imports into Dallas / Fort Worth from east / southeast of the DFW region

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Base Case Reliability Upgrades 2032

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Area Analysis BAU All Tech with DR

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Methodology:

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1. Develop a base-case with irresolvable constraints upgraded.

2. Identify scenario-specific import limitations into major load zones given most severe resource and element contingencies.

3. Create binding constraints to represent AC voltage stability limits in the DC / PROMOD Model.

4. Identify must-have reliability upgrades and economic supplements / alternatives.

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Dallas / Fort Worth Area: Base Case Upgrades

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From Bus To Bus kV Original Rating

New Rating

Line Length

new or upg

$M/Mi (2012)

Total Cost ($M, 2012)

Year

Tricorner Trinidad 345 1072 1969 40.5 upg 1.46 59.1 < 2022Big Brown Navarro 345 1072 1969 30.4 upg 1.46 44.4 < 2022Big Brown Navarro 345 1072 1969 30.4 upg 1.46 44.4 < 2022Trading House Sam Switch 345 1072 1969 22.8 upg 1.46 33.3 < 2022Trading House Sam Switch 345 1072 1969 22.8 upg 1.46 33.3 < 2022Cedar Hill Switch Watermill 345 1072 1969 17.3 upg 1.46 25.3 < 2022

Jewett 500kV Watermill 500kV 500 6928 135 new 2.98 402.30 <2032

Monticello 345 Allen Switch 345 345 1072 2987 102.4 upg 1.46 149.50 <2032

Royse Switch 345 Shamburger Switch 345 345 1072 2987 80.9 upg 1.46 118.11 <2032

Farmersville 345 Monticello 345 345 1072 2987 80.9 upg 1.46 118.11 <2032Navarro Watermill 345 345 1631 47 new 2.44 114.68 <2032Tricorner Trinidad 345 1631 40 new 2.44 97.60 <2032Venus Switch Sam Switch 345 1072 2987 37.9 upg 1.46 55.33 <2032Venus Switch Sam Switch 345 1072 2987 37.9 upg 1.46 55.33 <2032Wolf Hollow Rocky Creek 345 1072 2987 35.7 upg 1.46 52.12 <2032Big Brown Navarro 345 1072 2987 30.4 upg 1.46 44.38 <2032Big Brown Navarro 345 1072 2987 30.4 upg 1.46 44.38 <2032Valley SES Anna Switch 345 1793 2987 26.5 upg 1.46 38.69 <2032

Royse Switch 345 Allen Switch 345 345 1631 2987 22.8 upg 1.46 33.29 <2032

Trinidad Richland 345 1072 2987 18.7 upg 1.46 27.30 <2032West Levee Watermill 345 345 1631 2987 17.7 upg 1.46 25.84 <2032Cedar Hill Switch Watermill 345 345 1072 2987 17.3 upg 1.46 25.26 <2032

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Dallas / Fort Worth Area

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DFW Import Capability Issue

Options tested to improve DFW Import Capability

Options

Dallas Interface in AC Corresponding

Year in AC Analysis

Corresponding Year in DC Analysis MW Delta

Base Case 18890 0 2022 2028

Watermill-Jewett double circuit 500kV 19635 745 2024 2031

Navarro-Watermill double circuit 345kV 19175 285 2024 2032

Tricorner-Trinidad double circuit 345kV 19030 140 2023 2028

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DFW Economic Project Options - 2022

• Watermill-Navarro double circuit 345 kV option was evaluated for economy after demonstrating benefit in import analysis.

• While the option does not meet current economic criteria, it does increase import capability into Dallas and relieve nearby 345kV overloads.

Project Options Tested for 2022Length (mile)

Estimated Capital cost

(million in 2022)

Production Cost Savings (million)

Reliability benefit (cost realized by addressing or causing other overload

issues) (million)

Economic?

New Watermill-Navarro 345 kV line 47.4 150.18 0.2 (67.0) No

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DFW Economic Project Options - 2032

Project length

Estimated Capital cost (million in

2032)

Yearly prod cost saving

Reliability benefit (cost realized by addressing

or causing other overload issues)

(million)

Economic?

345 kV Venus-Tricorner-Royse 79 miles 335.2 2 135.6 No

Dallas east import 365 miles 1,382.40 5.1 1,342.20 No

•Dallas east import project solved significant overloads, and was very close meeting economic criteria (siting- specific solution.)

•The reliability / economic implications of these projects are dependent upon siting assumptions.

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DFW: Special Issues

• Increasingly urban areas present limited ROW to access loads from remote resources

• East to Dallas transmission projects are only necessary under scenario specific siting assumptions

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Houston Area: Base Case Upgrades

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FromBus ToBus kV Original Rating

New Rating Line Length new or

upg$M/Mi (2012)

Total Cost ($M, 2012) Year

South Texas Project WA Parish 345 1412 1969 68.3 upg 1.46 99.7 < 2022

Smithers Belaire 345 1137 1969 25.6 upg 1.46 37.3 < 2022

WA Parish Belaire 345 1137 1969 25.2 upg 1.46 36.8 < 2022

WA Parish Obrien 345 1450 1969 17.0 upg 1.46 24.8 < 2022

WA Parish Obrien 345 1450 1969 17.0 upg 1.46 24.8 < 2022

Canal Lufkin 345 NA 5974 138 new 2.44 336.72 < 2032

South Texas Project WA Parish 345 1412 2987 68.3 upg 1.46 99.7 < 2032

South Texas Project Dow Chemical 345 1450 2987 45.5 upg 1.46 66.4 < 2032

Smithers Bellaire 345 1137 2987 25.6 upg 1.46 37.4 < 2032

WA Parish Bellaire 345 1137 2987 25.2 upg 1.46 36.8 < 2032

South Texas Project Hillje 345 1195 2987 19.3 upg 1.46 28.2 < 2032

Lufkin Switch Berea REA 138 84 435.02 33.5 upg 0.75 25.1 < 2032

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Houston Metropolitan Area

Significant Issues:• Increased dependence on imported power and

limited opportunities for resource development internal to Houston metro region highlights the need for additional import paths.

• The dependence on the north-to-Houston import path limits opportunities to improve economic efficiency absent geographic diversity.

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Houston Metropolitan Area

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Houston Area Import Capability Issue

Options(double circuit 345 kV)

Houston Interface Limit (AC)Corresponding Year

in AC AnalysisCorresponding Year

in DC AnalysisMW Delta

Base Case* 8827 0 2022 2031

Fayette-O’Brien 345 kV 9346 519 2024 2032

Lufkin-Jordan 345 kV 9538 711 2026Beyond 2032 (no overload in 2032)

TNP One-Salem-Zenith 345 kV 9306 479 2024Beyond 2032 (no overload in 2032)

SO Texas-Hillje-O’Brien 345 kV 9149 322 2024Beyond 2032 (no overload in 2032)

Note: * The Fayette-Zenith 345 kV line has been removed from the study model

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Houston Area Economic Project Options - 2022

• Upgrading Green Bayou transformer is expected to provide economic benefit.

• Although Fayette-O’Brien, TNP One-Salem-Zenith, South Texas-Hillje-O’Brien 345 kV line are not economical, the options address potential overload issue on the W.A. Parish-O’Brien 345 kV line in the area.

Project Options Tested for 2022(all options are double circuit options)

Length (mile)

Estimated Capital cost

(million in 2022)

Production Cost Savings (million)

Reliability benefit (cost realized by addressing or causing other overload

issues) (million)

Economic?

New Fayette-O Brien 345 kV line 81.3 241.7 0.6 (108.8) No

New Lufkin-Jordan 345 kV line 138.1 430.2 4.1 36.79 No

New TNP One-Salem-Zenith 345 kV line 149.5 444.6 6.2 (105.3) No

Upgrade Gibbons Creek-Singleton 345 kV 9.4 23.8 0.5 n/a No

Upgrade Green Bayou 345/138 kV n/a 11.9 2.8 n/a Yes

Upgrade S. Texas-Hillje, and new Hillje-O’Brien 345 kV line

85.4 254.0 4.1 (54.1) No

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Houston Area Economic Project Options - 2032

• A new import path into the Houston Region was needed for stability in the 2032 case

• Study option Lufkin to Jordan was selected as a reliability fix for 2032

• Lufkin to Jordan was tested and demonstrated economy in 2030

Projects tested for 2032 Length(mile)Project

cost ($M in 2032)

Reliability benefit (upg

cost avoided) ($M in 2032)

adjusted cost/6 ($M in 2032)

prod cost saving in 2032($M)

economic?

500kV Zenith-TNP, 345kV TNP-Thouse 59(345kV)

+133(500kV)975.1 333.8 106.9 25.4 No

500kV Limest-Zenith 148 831.2 286.9 90.7 23 NoCongestion upgrade Houston 268.8 555 219.4 55.9 20.45 No

Project tested for 2030 Length(mile)Project

cost ($M in 2030)

Reliability benefit (cost

avoided) (million in

2030)

Adjusted cost/ ($M in 2030)

prod cost saving in 2030($M)

economic?

Lufkin-Jordan 345kV 138 504 385.5 19.8 29.9 Yes

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Houston Area Special Issues: Demand Response

The BAU / All Technology Study introduces demand response to the planning model:

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CityCapacity (MW)

Industrial Residential/Commercial

Austin 60 275Dallas 160 733

Houston 200 734San Antonio 80 458

Absent Demand Response in this model:

•The Houston Area Import constraint would be overloaded one year sooner (2030)

•The Lufkin to Jordan line would no longer maintain voltage stability in the Houston region up to the year 2032

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Austin / San Antonio Area Base Case Upgrades (2032)

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FromBus ToBus Line or Xfmr kV Original Rating New Rating Line Length new or

upg $M / Mi Total cost ($M 2012)

Hill Country Skyline Line 345 1171 2987 10.8 upg 1.46 15.77

Marion 345 Marion 138 Transformer 138 478 478 0 new 7.98

Cagnon 345 Cagnon 138 Transformer 138 600 600 0 new 7.98

Cagnon 138 VLSI Line 138 331 789 8.7 upg 0.75 6.53

Cedar Valley CopperAS Cove Line 138 171 435.022 27.3 upg 0.75 20.48

McNeil Marshall Ford Line 138 221 435 14.5 upg 0.75 10.88

Garfield Hicross Line 138 480 789 13.8 upg 0.75 10.35

Howard Lane Jollyville Line 138 480 789 7.7 upg 0.75 5.78

Leander Nameless Line 138 221 789 6.8 upg 0.75 5.10

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Austin/San Antonio Areas

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Austin/San Antonio Areas

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Significant Issues:• Increased dependence on imported power and

limited opportunities for resource development internal to San Antonio 345kV Loop highlights the need for additional import paths.

• Limited strong sources from the West places increasing dependence upon 138kV transmission in Austin.

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Austin/San Antonio Areas Import Capability

Map of Options to Improve San Antonio/Austin Import Capability

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Austin/San Antonio Areas Import Capability

San Antonio Area Import Capability from Voltage Stability Perspective• 13,209 MW at San Antonio/Austin• Critical contingency: Hill Country-Marion & Skyline-Marion under G-1

Options

San Antonio Interface LimitCorresponding

Year in AC Analysis

Corresponding Year in DC

AnalysisMW Delta

Base Case 3033 0 2027-2028

Beyond 2032 (no overload in

2032 Base Scenario)

Elm Creek – Spruce 345 kV double circuit line

3118 85 2028-2029

Kendall – Hill Country 345 kV double circuit line

3076 43 2028-2029

Lon Hill – Pawnee – Spruce Line upgrade

3069 36 2028

345 kV double circuit line from Cagnon – Miguel

3285 252 2029

500 kV double circuit line from Comanche peak – Edinburg

4443 1410 >2030

500 kV circuit from Newton – Miguel- Lon Hill

4187 1154 >2030

500 kV circuit from Kendall – Miguel – Lon hill

4008 975 >2030

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Austin/San Antonio Areas : Special Issues

• Hill Country to Skyline, absent incremental import capacity, will be overloaded by 2032.

• Congestion on to the SA loop is observed prior to 2032.

• A new western 345kV source may be difficult to terminate at existing switchyards on the 345kV loop.

• Western source needs for the Austin area merits further study.

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Austin/San Antonio Area Economic Project Options - 2022

Project Options Tested for 2022(all new 345 kV lines are double circuit options)

Length (mile)Estimated Capital cost

(million in 2022)Production Cost Savings (million)

Reliability benefit (cost realized by addressing or causing other overload

issues) (million)

Economic?

Cagnon-Miguel 345 kV 65.0 193.3 3.0 87.40 No

Cagnon-Miguel 345 kV & Cagnon 345/138 kV 65.0 217.1 4.5 n/a No

Cagnon-Pawnee 345 kV 81.3 241.7 3.7 137.33 No

Cagnon-Pawnee 345 kV & Cagnon 345/138 kV 81.3 265.4 4.9 n/a No

Kendall-Hill Country 345 kV 48.8 145.0 (8.2) n/a No

Upgrade Elgin-Taylor 138 kV 11.4 15.3 1.0 n/a No

Upgrade Hill Country-Skyline 345 kV 10.8 30.3 1.2 n/a No

Additional path(s) from the South into the San Antonio area will significantly relieve the loading on the Hill Country-Skyline and Spruce-Pawnee (assumes incremental generators sited South of S.A.)

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Austin/San Antonio Area Economic Project Options - 2032

Project Length

Estimated Capital cost (million in 2032)

yearly prod cost saving

Reliability benefit (cost realized by addressing or causing other overload

issues) (million)

economic?

500kV Lnhill-Migel-Cagnon 191 1,106.70 2.5 379.9 NoCongestion upgrade San Antonio 109 252+83 11 222.3 No

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Lower Rio Grande Valley Base Case Upgrades

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FromBus ToBus Line or Xfmr kV Original

RatingNew Rating Mi new or

upg $M/Mi Total Cost ($M, 2012) Year

Weslaco Stewart Line 138 157 435 14.66 upg 1.1 16.1 <2022

Abilene Callahan Line 138 135 435 19.2 upg 0.75 14.4 <2032

Wormser Rio Bravo Line 138 455 789 9.9 upg 0.75 7.4 <2032

Aderhold Duke Line 138 235 435 7.6 upg 0.75 5.7 <2032

Elsa Aderhold Line 138 235 435 7.12 upg 0.75 5.3 <2032

Barney Davis Rodd Field Line 138 320 789 7.1 upg 0.75 5.3 <2032

Celanese Bishop Kleberg Line 138 211 435 6.1 upg 0.75 4.6 <2032

South McAllen Las Milpas Line 138 157 435 5.9 upg 0.75 4.4 <2032

Holly Rodd Field Line 138 320 789 5.21 upg 0.75 3.9 <2032

Airline Cabaniss Line 138 320 789 4 upg 0.75 3.0 <2032

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Reliability/Congestion Issues –LRGV for 2022 and 2032

The Lower Rio Grande Valley (LRGV) was studied with the following scenario specific assumptions:

1400 MW of thermal generation sited in the LRGVRPG approved projects in serviceLargest CCGT in service / outaged

Given these assumptions, no congestion or reliability issues were observed for the selected study years.

The following sensitivities were tested:

Maximum MW Flow on LRGV Interface Observed in PROMODDuring 2032 Peak Load Condition Under Different Generation Assumption

Sensitivity Scenario Maximum Flow (MW)Violated Interface Limit (2512 MW) ?

With new expansion unit sited in LRGV 918 No

With new expansion units sited outside LRGV 2048 No

With new expansion units sited outside LRGV and

With the major existing combined cycle units in LRGV offline

2691 Yes

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LRGV: Study Assumption Sensitivities

Absent resource development in the LRGV, for the most severe generation contingency, incremental import capacity is needed in 2028 for voltage stability.

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Without Expansion units modeled inside LRGVAnd With Major Existing Combined Cycle Unit

offlineMonth Year Flow (MW)

Interface Limit Applied

(MW)

Violated Interface Limit?

Maximum MW Flow in 2028, 2029, 2030 and 2032 on LRGV Interface

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2032 2691 2512 Yes

2030 2620 2512 Yes

2029 2566 2512 Yes

2028 2434 2512 No

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Preview of Scenario 2 – BAU with NG Retirements

Scenario 2 assumes retirement of NG fired resources after 50 years

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TH Wharton – All units (1022 MW)

Greens Bayou – All units (354 MW)

Cedar Bayou -1,2 (1494 MW)

Sam Bertron -1,2 (348 MW)

W A Parish -1,2,3,4,T1 (1191 MW)

Sam Rayburn – GT1,GT2,3 (52 MW)

B M Davis 1 (335 MW)

Silas Ray 5 (17 MW)

Pearsall -1,2,3 (74 MW)

VH Braunig – 1,2,3 (862 MW)

O W Sommers - 1,2 (810 MW)

Dansby 1 (110 MW)

Atkins 7 (20 MW)

Sim Gideon - 1,2,3 (620 MW)

Decker- 1,2 (748 MW)

Trinidad 6 (226 MW)

Stryker Creek -1,2 (673 MW)

Graham - 1,2 (615 MW)

Handley – 3,4,5 (1266 MW)

R W Miller - 1,2,3 (403 MW)

Mountain Creek -6,7,8 (808 MW)

Ray Olinger -1,2,3 (331 MW)

Powerlane Plant -1,2,3 (88 MW)

Lake Hubbard -1,2 (916 MW)

Ferguson (425 MW)

2006-2010 2011-2015 2016-2020 2021-2025 2025-2030

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Summary: 2022/2032

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Dallas / Fort Worth: Incremental import paths will be needed by 2022

•Scenario-specific assumptions place most incremental resources South and Southeast of the DFW area. Future scenarios will be studied to determine the impact to import path needs.

•Dynamic and static reactive solutions may maintain voltage stability / delay the need for incremental import paths.

Houston Metropolitan Area:Incremental import paths will be needed by 2022

•Scenario-specific assumptions place most incremental resources South and North of the Houston Metro region.

•Certain import path upgrades demonstrate economy before a reliability required in-service year.

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Summary: 2022/2032

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Austin / San Antonio: Strong sources west of the Austin / San Antonio region aide economy and voltage stability

•Increased dependence on imported power in the Austin / San Antonio Area merits further study.

•Congestion and base-case overloads on the 345kV connections to the San Antonio ring support the need for incremental 345kV import paths.

•Increased imports to support voltage stability in the San Antonio are needed by 2028 (assuming limited or no development of incremental resources within the 345kV loop)

Lower Rio Grande Valley:Limited congestion, overloads, or voltage stability issues are seen with incremental resources developed in the LRGV

•Scenario-specific assumptions site incremental resources in the South and LRGV. •Absent resource development local to the area, incremental imports are needed by 2028 for voltage stability.

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Questions?

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