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Overcoming Transmission Line

Siting Challenges

Case Study

Middletown-Norwalk Project

NARUC Transmission WorkshopApril 21, 2011

Albert W. Cretella, III

Presentation Overview

Project Description

Need, Route Options, Steps to ID Best Solution

Siting Challenges

Overhead Lines

Underground Lines

Techniques & Technologies Used

Route Variations & Bypasses

Low Magnetic Field Designs

Underground Cable

River & Rail Crossing Methods

Summary & Closing Thoughts

2

Connecticut Energy Situation

Daily total imports are approximately 1,500 MW

Long Island

RIMA

NY

0

Most of the time Connecticut uses more power than it generates.

Most of Connecticut’s imported power moves on a 345-kV system.

SWCT consumes half the state’s electricity.

But the 115-kV system in SWCT limits the movement of power to where it’s needed

►

►►

► 345-kV

115-kVPower Plant

50%

0

3

Determining a Solution

What is the best combination of solution components?

PROPERTY IMPACT

Impact on homes &

property; Visual impact

ENVIRONMENTAL IMPACT

Impact on wildlife, vernal pools,

aquifers

SYSTEM BENEFIT

Operability†,

Reliability†

TECHNICAL FEASIBILITY

Can it be engineered? Can

it be built?

COST to CUSTOMERS

Engineering and

Construction Costs

† Per national and regional reliability standards.

What are the components of the solution?

Overhead Point-to-Point

Options

Underground Point-to-Point

Options

Evaluate each option based on

these criteria

Evaluate each combination based

on these criteria

What needs to be done?*

* Per regional planning led by

ISO-New England.

1.Strengthen power source to a point in Wallingford

2. Connect that source to substations in Milford, Bridgeport, and Norwalk

1

1

2

2

2

4

Middletown

Norwalk

2

2

2S/S

S/S

S/S

1

1

S/S

To meet national and regionalreliability standards…

Step 1: What needs to be done?

5

Step 2: What are the options?

6

I-91, I-95

Wilbur Cross

Amtrak Railroad

Conrail Railroad

East Devon

Scovill Rock

?

Beseck

Transmission ROW

Secondary Roads

7

What is the best combination of solution

components?

What are the components of the

solution?

Overhead Point-to-Point

Options

Underground Point-to-Point

Options

1

Step 3: What are the best options?

PROPERTY IMPACT

Impact on homes & property; Visual impact

ENVIRONMENTAL IMPACT

Impact on wildlife, vernal pools, aquifers

SYSTEM BENEFIT

Operability†,

Reliability†

TECHNICAL FEASIBILITY

Can it be engineered? Can it be built?

COST to CUSTOMERS

Engineering and construction costs

† Per national and regional reliability standards.

Evaluate each option based on

these criteria

Evaluate each combination based

on these criteria

8

Choosing a Route / Design was an Iterative Process

m nDecision

Circle

Environmental Review

Phenix Environmental, Inc.

Historical

Raber Associates

EnvironmentalTopology

Water ResourcesCoastal Area

CulturalSSES

Marine Options

ESS

EMF/ Best Practice

Exponent

CB Ellis

Property Impact

Underground Technology

Underground Construction

PDC

JD Hair

Transmission &

Substation Design

Burns & McDonnell

Routing & Criteria

Burns & McDonnell

HVDC

Black & Veatch

Singer Substation Site

Black & Veatch

Noise

Cavanough & Tocci

General Electric

ISO-NE

NU

System Studies

9

OH 345-kV (circuit miles)

OH 115-kV (circuit miles)

UG 345-kV XLPE

(circuit miles)

UG 115-kV XLPE

(circuit miles)

Greenfield S/S Sites

Upgrade S/S Sites

Acquisition Acres Land / # Homes

M-N Project (Budget

$1.400 B)

52 63 48 5 3 2 28.6

0

Alternative A (Budget

$1.350 B) 67 73 26 5 4 2

81.6 2

Alternative B (Budget

$1.272 B) 78 86 4 5 4 2

142.3 31

M-N Project and Alternatives

10

Middletown-Norwalk Summary

69 miles of 345-kV line

57 miles of 115-kV line

3 new substations

2 existing substation upgrades

Construction in 18 towns

In-Service Date: December 2008

Middletown

Haddam

Durham

Middlefield

Wallingford

Meriden

Cheshire

Hamden

Bethany

Woodbridge

Orange

West Haven

Milford

Stratford

Bridgeport

Fairfield

Westport

Norwalk

24 miles of XLPE underground

45 miles of overhead

1 mile of XLPE underground

56 miles of overhead

Why This Solution…

Going underground is 50% shorter

The underground option avoids the environmental and social impacts of having to acquire over 100 acres and up to 29 homes

The reduced length, avoided real estate costs, and construction difficulty make going underground virtually cost-neutral to going overhead

Why underground from Milford to Norwalk?

No ROW expansion is needed except for 2.5 miles in an unpopulated area of Haddam/Middletown

Nine of the 13 towns would see a net reduction in the number of poles in the ROW

Most towns would experience no discernible increase in pole heights from what exists today

Why overhead from Middletown to Milford?

12

EMF

ROW acquisition (condemnation of residential homes)

Viewscape

Permitting (wetland)

Existing ROW rights

Constructability

Overhead

Design & Construction Challenges

13

Magnetic Field Mitigation

New Applicant Requirements:

• Mapping requirement to identify “Statutory Facilities” (i.e., residential areas, private or public schools, licensed child day care facilities, licensed youth camps and public playgrounds) in the vicinity of the proposed OH route.

• Assessment of the impact of electromagnetic fields.

Connecticut Public Act No. 04-246

14

Protection from Magnetic Fields

• Electric fields are a function of

voltage – higher voltage causes

higher electric fields

• Magnetic fields are a function of

current (Amps) – higher current

causes higher magnetic fields

• Power is a function of Volts

times Amps

• For the same amount of power,

higher voltage means less

current therefore lower magnetic

fields

• There is no practical way to

shield magnetic fields, but there

are ways to reduce them

15

Strategies to Reduce Magnetic Fields

1. Add Distance

Widen the ROW

Increase Pole Height

Relocate the Line

2. Optimize phasing to maximize field cancellation

A

B

C

C

B

A

3. Optimize combination of

the structures

16

Split Phase Construction

Structure Type B – 345 kV

Split Phase

Structure Type C – Combination

345/115kV Split Phase

Structure Type E – Horizontal Split

Phase

17

Cross Section 1Scovill Rock S/S to Chestnut Junction (2.6 miles; 335’ ROW)

Middletown

Existing Proposed Option 1 Option 3

80’ 80’ 85’ 80’ 80’ 105’

($2.1M/mile) ($2.1M/mile) ($3.1M/mile)

mG on South/East Edge of ROW

Option 3Option 1ProposedExisting

32.6

18.6

6.2 7.5

mG on North/West Edge of ROW


33.830.1 28.8 29.6

80’ 80’ 80’

(15 GW Case) (15 GW Case)

18

Cross Section 2Oxbow Junction to Beseck S/S (7.0 miles; 125’ ROW)

Haddam, Durham, Middletown, Middlefield, Wallingford

Existing Proposed Option 2 Option 3

105’

($2.8M/mile) ($6.7M/mile) ($7.5M/mile)

mG on South/East Edge of ROWmG on North/West Edge of ROW

57’ 105’

Option 6 ($TBD M/mile)

135’

Bypass Royal Oak by placing 345-kV

on new ROW.

Existing 115-kV remains.

115-kV 115-kV

62ProposedExisting

13.917.1

12.4 12.4*

6.2

3 62ProposedExisting

8.3*

30.4

12.49.2

6.2

3

* EMF value for 115-kV only


19

Royal Oak Neighborhood Bypass

Significant

Wetland

Impacts

Significant

Tree Clearing

Property Condemnation

Bypasses may not be Least Environmentally Damaging Practical Alternative20

Cross Section 7BCheshire Town Line to Cook Hill Junction (0.4 miles; 200’ ROW)

Cheshire

Existing Proposed Option 1 Option 2 ($8.4M/mile) ($9.0M/mile) ($12.5M/mile)



0.4

6.2 5.5

1.1



4.4

17.9

13.4

5.8

90’130’90’

130’

115-kV 115-kV

150’

115-kV

2


21

Cross Section 8-SouthPease Road Junction to East Devon S/S (12.0 miles; 165’ ROW)

Woodbridge, Orange, Milford

85’80’

Existing Proposed Option 4 Option 5 ($3.8M/mile) ($5.0M/mile) ($5.5M/mile)



3.9

11.2

1.7 0.6



1.6

16.0

5.92.9

80’80’57’57’

105’


110’ 135’

22

Jewish Community Center Bypass

23

Underground

System Limitations Operation &

Maintenance Concerns Traffic/Public & Worker

Safety DOT/Local Constraints Cost Railroad/Bridge/ River

Crossing Methods Soil/Water Handling Conflicts w/other

Utilities Residential & Business

Disruption

Design & Construction Considerations

24

• How much underground cable can system handle

– What are O&M implications of UG lines

• Shortest route is always better – can it be built?

• CT Siting Council approved route along 14 miles of State roadways (shortest and straightest route)

• DOT resisted use of State roadways due to potential traffic impacts and safety concerns

• DOT originally wanted the duct bank 8 feet deep which would be too deep for the heat to dissipate and would reduce the capacity of the line

• DOT wanted all vaults to be located outside of the travel roadway – needed to find off street locations

• How to cross rivers and railroads

Underground Challenges

25

Cable Types

Cable Type

Maximum

Voltage

Electrical

Advantages

Electrical

Disadvantages

High-pressure Fluid-filled

(HPFF) 345kV +

Most Common at

>230kV

Higher VAR

Consumption,

Leaking oil

High-pressure Gas-filled

(HPGF) 138kV Lower Capacitance

Higher VAR

Consumption,

Uncommon

Extruded-dielectric

(XLPE) 345kV +

Higher Rating than

HPFF, Lower VAR

Consumption, Low

Maintenance

New to the United

States at 345kV+

Extruded-dielectric (EPR) 138kV

More Flexible than

XLPE

Higher Electrical

Losses than XLPE

Self-contained Fluid-filled

(SCFF) 345kV + High Voltages

Dielectric Fluid,

Higher VAR

Consumption than

XLPE, Uncommon 26

• Maximizing system reliability – minimize splices

• Cable length that can be loaded on reels – maximum 1800 feet

• Electrical requirement to space each set of 4 vaults about equally

• Maximum cable pulling tensions

• Location of water and railroad crossings - fixed or “hard coded” vault

locations due to river crossings

• Maximizing the number of off-street vault locations

• Minimizing impacts to existing businesses (condemnation and

business disruption claims)

• Location of off road wetlands

• Avoidance of existing utilities

• Avoidance of intersections

Factors Impacting Vault Locations

27

Water / Rail Crossing Methods

• Horizontal Directional Drill (HDD)

• Horizontal Auger (Jack and Bore)

• Self-Supporting Utility Bridge

• Open Cut (Trenching with Cofferdams)

• In-Street Trenching

• Attachment to DOT Bridges

Evaluation Criteria

• Conformance with Siting Council Decision and Order

• Minimize Impact to the Environment

• Minimize Social Impact

• Minimize Construction Risk

• Minimize Construction Schedule

28

UG Route Change

No feasible

crossing

method

Very busy

commercial

area

29

Options to Cross Ash Creek

ConnDOT Bridge Attachment

• Structurally Infeasible

HDD – Unacceptable Risks

Unfavorable Subsurface Conditions

• Mixed Face Soil Conditions /

Shallow Drill Path - Risk of

Construction Failure – Release

of drilling mud (Frac-Out)

Staging Area - Unsatisfactory

• Demolition of business at 58 Post Road in Fairfield

• Eliminates Entire business parking Lot in Bridgeport for 2 - 3 months

Jack & Bore – Not Constructible

Open Cut – Environmentally Devastating

30

Ash Creek Crossing

Original Proposal

• Self-Supporting Utility Bridge

• 160 Foot Clear Span

• 4 - 5 Month Construction Duration

• Bridge Located Outside of Town Public Access Easement

• Design Provides Shoreline Access Around Bridge Abutments and Under Bridge

• Minor Impacts to Intertidal Area

31

Proposed Utility Bridge at Ash Creek

Building Demolition Elimination of Parking for 2-3 months32

Mock-up of Utility Bridge at Ash Creek

This attempt to provide residents a “visual representation” did not go

well and resulted in a petition to DEP due to proposed crossing method

33

Ash Creek Permitting Background

• Extensive feasibility / design completed to determine the

least environmentally damaging practical alternative

• DEP hearings conducted due to petition associated with

the construction method

• After DEP hearings and extensive discussion the Town

of Fairfield, City of Bridgeport, ConnDOT and DEP

eventually agreed to permit an HDD within the State

roadway under the existing bridge

• Town of Fairfield, City of Bridgeport and ConnDOT

signed Memorandum of Understanding to ensure that all

understood the impacts of an HDD within the roadway

34

Ash Creek Horizontal Directional Drill

• One circuit on each side of road

• Each circuit bundle of 5 conduits

• Drill path was “steep and deep” to get

under bridge abutments

• Circuits separated and spaced far

apart to address cable overheating

concerns

• Construction mostly night work in 12-

hour shifts 6 days per week35

Ash Creek-Northwest Corner

36

Ash Creek-Northeast Corner

37

Construction Duration for Each HDD

• 30 days to install traffic

control and Mobilize HDD

equipment

• 8 days to drill pilot hole

• 30 days to ream pilot hole to

proper diameter

• 45 days to fuse conduits for

pull back

• 2 days conduit pull back

• 12 days to clean/test conduits

• 30 days to remove traffic

control, restore road and

demobilize

NOTE: Blue items occur in

expanded work zone.

Each HDD took over 5 months to complete

Typical Horizontal Directional Drill Setup38

Saugatuck River Crossing

39

Saugatuck River Crossing

• Horizontal Directional Drill

• 1563 feet in length – Max

40’ deep

• 2 – 3 month construction

duration

• Subsurface conditions –

Marginal

• Drill side staging area –

Adequate

• Conduit side staging area

– somewhat constrained

residential street

Result

• Hit target exit point

• Frac-outs cleaned up with

no impacts to coastal /

environmental resources40

Managing Stakeholder Conflicting Priorities

• State Siting Authority

• Federal Agencies - ACOE, NPS, USF&W, OLISP

(Office of Long Island Sound), etc.

• Municipal Leaders

• State Dept. of Transportation

• State Dept. of Environmental Protection

• State Dept. of Health

• Residents

• Businesses

• Other Utilities

Communication, engagement and compromise for

the greater good are essential

41

ConfigurationCircuit Miles

$ M/Circuit Mile

Range / AveInfluencing Factors

345-kV OH 52 $2.3 – 4.0 / $3.4Single / Double Circuit

Low EMF Designs

345-kV UG 46 $12.8 - 13.9 / $13.2Double Circuit Duct Bank

River / RR Crossings

115-kV OH 63 $1.5 – 3.0 / $2.1 Single / Double Circuit

115-kV UG 1 $7.5 / $7.5 Single Circuit Duct Bank

M-N Project Cost Summary

Underground transmission lines can cost 4 to 6 times more than

overhead transmission lines on an adequately sized existing ROW

42

Closing Thoughts

• Every projects’ use of various technologies must be evaluated on its own merits

• Cost/mile comparisons of OH and UG can be deceiving

• State Siting Regulators should strive to streamline / shorten the siting approval process – 2 plus years is too long

• State Siting Regulators should be cautious about delegating decisions to municipalities

• Legislators can provide

leadership roles in

coordinating stakeholders –

State and Federal agencies,

municipal leaders,

businesses and residents 43

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