Navarro to Houston
Presentation to ERCOT RPG
August 27, 2013
Independent studies by three TSPs identify a need for
additional North to Houston injection
Need for Houston Import
• North to Houston (N-H) flows increased to 3,100 MW
– Summer 2012, 75% quartile for N-H, 3,102.9 MW
• Current grid
– G-1 case results in more constrained conditions in terms of
Houston load deliverability prior to running into thermal/voltage
stability concerns
– Singleton – Zenith double circuit line overload observed as most
limiting element
Additional overloads observed along the existing N-H corridor
– Thermal constraints observed to be more limiting than voltage
stability constraints
In Summer 2012, North to Houston flows exceeded the
ERCOT expected 2018 flows 27% of the time
2
ERCOT should endeavor to provide long-lasting benefits for
Houston that also strengthen the larger grid
Need for Comprehensive Analysis
• With 3 proposals for Houston import, ERCOT has the
unique opportunity to:
– perform a comprehensive, comparative analysis of the various
options
– identify a solution that will provide lasting reliability benefits for
the fast-growing Houston area
– coordinate major studies in development related to oil and gas
load and Panhandle wind with Houston import to achieve
benefits both to Houston and to the larger grid
3
Evaluation Methodology
Screening Criteria
• Lone Star analyzed the Houston area and ERCOT grid
with the goal of identifying projects that would provide
the following:
–
–
–
–
Increased incremental import capability into Houston
Route diversity and grid security
Access to North Zone generation
Strong link to CREZ renewable generation
Navarro projects meet each of the above criteria
4
Navarro Substation should be considered for the northern
terminus of any Houston Import Project
Navarro Substation Benefits
• Navarro options provide higher incremental import
capacity to Houston
• Navarro is strongly connected to over 10 GW of existing
North Zone generators
• Navarro connects nine existing 345 kV lines and would
create routing diversity versus existing Houston
connections
• Navarro is the eastern terminus of CREZ and offers the
most direct path for CREZ wind to reach Houston
• Navarro is state-of-the-art and readily expandable
5
Three Navarro options merit careful consideration for their
benefits
Recommended Houston Import Solutions
•
Navarro to King 345 kV with 50% Series
Compensation
– High incremental transfer, 3,238 MW
– Strong Alternate Routing
– Strong link to CREZ and North Zone generators
•
Navarro to King 500 kV
–
–
–
–
–
Highest incremental transfer, 3,558 MW
Strong Alternate Routing
Strong link to CREZ and North Zone generators
Start of 500 kV backbone
Requires the fewest upgrades to obtain >3,500
MW of incremental transfer
– Can initially operate at 345 kV
•
Navarro to Gibbons to Zenith 345 kV
– 2,700 MW of incremental transfer
– Strong link to CREZ and North Zone generators
6
A 500 kV line would provide strong benefits to Houston and
the entire ERCOT grid
500 kV Advantages
• Highest incremental Houston import capability
• Lower line losses
• Lower impedance: can divert bulk power to unload and
relieve constraints on underlying lower voltage systems
• Expandable backbone connecting two major load centers
(Dallas and Houston) to renewable and thermal generation
• Lone Star’s Navarro substation has room for expansion and
uses 500 kV breakers on the existing lines at Navarro, Sam
Switch, and West Shackelford
• Lone Star’s affiliate has expertise building and operating
over 1,100 miles of 500 kV
7
Appendix
Navarro Substation is a strong connection point to multiple
North Zone generators and CREZ
Midlothian
Freestone
Navarro
Bosque County
Big Brown
CREZ
Trading House
Sandy Creek
Limestone
Jewett
Twin Oak
TNP One
Temple
Jack Crk
Gibbons Crk
Singleton
Sandow
Lost Pines
King
Zenith
Fayette
O’Brien
Holman
WA Parish
Hillje
STP
9
Historical North to Houston Flow
10
The studied base case reflects ERCOT existing generation
and load projections
Study Model Development
•
•
•
•
•
•
•
11
Included WA Parish Addition (NG): 90 MW
Included Channel Energy Center (NG): 190 MW
Removed Pondera King (NG): 1,380 MW
Removed Deepwater Energy Storage: 40 MW
Removed Deer Park Energy Center (NG): 192 MW
Removed Agrifos Steam Unit (NG): 0 MW
Removed Tenaska’s switchable Frontier units (NG): 885
MW
The studied base case reflects ERCOT existing generation
and load projections
Reliability Criteria
• ERCOT Criteria per Planning Guide 4.1.1.2 (1) (b)
“With any single generating unit unavailable, followed by Manual System
Adjustments, followed by a common tower outage or the contingency loss
of a transmission circuit or transformer, all Facilities shall be within their
applicable Ratings, the ERCOT System shall remain stable with no
cascading or uncontrolled Islanding, and there shall be no nonconsequential Load loss. “
• Thermal Analysis used the loss of the largest unit inside
Houston – Cedar Bayou 2: 745 MW
• Voltage Stability Analysis used the loss of the Gibbons
Creek unit: 470 MW
12
The studied base case reflects ERCOT existing generation
and load projections
Voltage Stability Evaluation
• N-1 and N-1+G-1 analysis with loss of Gibbons Creek unit
• Houston Import Capability limited to 1,810 MW
• Voltage Stability Limit was not observed to be the binding
constraint on North to Houston import in comparison to
thermal constraints
• Thermal analysis was used as the primary gauge of
evaluation of the studied transmission options
13
All Preferred Options from CNP, GP&L/CTT, and Lone Star
Houston Import Projects sorted by Incremental Import Capability
Proposer Option
Number
Option Description
Incremental
Houston Import
Capability (G-1)
(MW)
Transmission
Cost
MW/$MM
Option
Estimate
Length
($ MM)*
(miles)
LST-17
LST-7
LST-13
LST-5
LST-10
CNP-15
CNP-25
GP&L/CTT-9
GP&L/CTT-4
GP&L/CTT-1
Navarro - King (500 kV)
Navarro - King (50% SC)
Navarro - Tomball (345 kV)
Navarro - King (345 kV)
Navarro - Gibbons Creek - Zenith 345 kV
Twin Oak - Zenith 345 kV
Limestone -Ragan Creek - Zenith 345 kV
Limestone - Gibbons Creek - Zenith 345 kV
Gibbons Creek - Tomball 345 kV
Gibbons Creek - Zenith 345 kV
3558
3238
2946
2739
2717
2701
2532
2517
2204
2010
166
166
162
166
165
117
93
122
50
60
674
552
474
512
417
462
532
333
203
217
5.28
5.87
6.22
5.35
6.51
5.85
4.76
7.56
10.86
9.26
CNP-24
Ragan Creek - Zenith 345 kV
1960
69
305
6.60
*
Cost Estimates include substation costs and required upgrades.
*
Cost estimates submitted by CNP, GP&L/CTT, and Lone Star are not made on the same basis.
14
Detailed Cost Estimates of Lone Star’s Preferred Options
Option
Project Description
Project length (miles)
Transmission
T-line Supply & Install
T-line Land/Development/Other
Total Transmission Costs
Substation
Substation Supply & Install
Substation Land
Total Substation Costs
Transmission Addition Cost
LST 7
Navarro - King 345
kV (50 % Series
Compensation)
LST 5
Navarro - King 345
kV
LST 17
Navarro - King 500
kV
LST 10
Navarro - Gibbons
Creek - Zenith
166
166
166
165
$
$
$
279,620,000 $
91,300,000 $
370,920,000 $
279,620,000 $
91,300,000
370,920,000 $
494,680,000 $
$
494,680,000 $
262,210,000
90,750,000
352,960,000
$
$
$
$
49,230,000
1,250,000
50,480,000
421,400,000
$
$
$
$
10,230,000 $
1,000,000
11,230,000 $
382,150,000 $
50,435,200 $
$
50,435,200 $
545,115,200 $
24,220,000
300,000
24,520,000
377,480,000
Transmission Addition Cost
Network Upgrade Costs (System
Reinforcements)
$
$
421,400,000 $
130,990,000 $
382,150,000 $
129,810,000 $
545,115,200 $
129,810,000 $
377,480,000
39,630,000
Total Proposed Project and
Network Upgrades
$
552,390,000 $
511,960,000 $
674,925,200 $
417,110,000
Incremental Transfer Capacity (MW)
MW/$MM with upgrades
Cost per Mile
Cost Estimate Source
15
3238
5.86
2739
5.35
$
2,234,458 $
2,234,458 $
NextEra Energy E&C
NextEra Energy E&C
3558
5.27
2717
6.51
2,980,000 $
2,139,152
ERCOT Generic
NextEra Energy E&C