POWER LINE CLEARANCE AND LANDSCAPES UNIT

IntroductionDavid Bayard PLC and Landscapes Manager

- Tree Care industry since 2000- ISA CA (2009), ISA TRA Qualified (2013)- WA DNR Urban and Community Forestry

Council (2017)- Seattle UF Core Team- Recreational Tree Climbing company owner/facilitator (2011)

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SEATTLE CITY LIGHT SYSTEM OVERVIEW

Public Power Generator, Transmitter, Distributor• 10th Largest Public Utility in the U.S.

o 430K Meterso 656 Trans. (506 NERC), 2300 Dist., 317 Network Circuit-Mileso 7 Hydroelectric Generation siteso 16 Major Substations

* Data from https://www.publicpower.org/public-power/stats-and-facts

68%

15%

13% 4%

Electricity Providers in U.S. by Market Share

IUOs Public Power

REC Power Marketers

Public Power:*2,011 Utilities (60%)

https://www.publicpower.org/public-power/stats-and-facts

Generation – Transmission - Distribution

Seattle City Light System OverviewTransmission System Distribution Service Territory

Organizational Context

Organizational Context

Seattle City Light’s Power Line Clearance and Landscapes Unit

Mission:PLC&L is committed to ensuring safe and reliable power delivery through the comprehensive and environmentally responsible management of the vegetation our lines and infrastructure impact.

Budget #s (2018)

• City Light – $1.4 B• T&D Operations O+M - $77M • PLC&L - $10M

– Labor $2.1M– Dist PLC - $6M (contract tree-trimming)– Trans ROW Maint - $500 K– Landscapes Maint - $150 K– Urban Forestry – $250K

Distribution Tree Trimming Program

• Maintains and monitors over 300,000 trees with grow/fall in potential

• Trims over 2300 circuit-miles of overhead lines in Seattle and parts of Burien, Lake Forest Park, Normandy Park, Renton, SeaTac, Shoreline, Tukwila and Unincorporated King County.

Typical Distribution System Facilities

D

A

J

E

F

H

B

I

G

C

Dist Tree Trim Methodology• Feeder-based

• 4-5 yr. cycle for entire service area

• All regular maintenance tree trimming done by contractors

• Vegetative clearance distances informed by WA WAC 296-24-960,tree care industry BMPs and budget.

• Directional Pruning (“natural” or “drop-crotch”) – an increased focus on proper arboriculture yields “deeper” cuts 1st time around. No “rounding over” or “shaping”.

• All contractors are Journey-level Tree Trimmers or apprentices. All work identified (notified) and audited by ISA Certified Arborists (CA)

• All Contract Tree crews have min. 1 ISA CA per crew – anomaly in the industry

Transmission Right-of-Way Maintenance Program

• Manages vegetation along 656 circuit-miles of transmission lines through King, Snohomish, Skagit, Whatcom and Pend Oreille counties.

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Transmission Right-of-Way Maintenance Program

• - Work Managed on 2 yr. cycle informed by annual inspections.

• - 230kV system Subject to Federal regulation

Transmission Right-of-Way Maintenance Program

• Min Clearances informed by WAC, NERC and Cycle

• Follow Wire-Zone – Border-Zone BMPs

Seattle City Light Minimum Vegetation Clearance

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

60 150 240 330 420 510 600 690

Line Voltage in kilovolts (1000 volts)

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umum

Veg

etat

ive

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aran

ces

in F

eet

Chart1

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70

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Minimum Vegetation Clearance (feet)

Line Voltage in kilovolts (1000 volts)

Minumum Vegetative Clearances in Feet

Seattle City Light Minimum Vegetation Clearance

10.3333333333

10.6666666667

11

11.3333333333

11.6666666667

12

12.3333333333

12.6666666667

13

13.3333333333

13.6666666667

14

14.3333333333

14.6666666667

15

15.3333333333

15.6666666667

16

16.3333333333

16.6666666667

17

17.3333333333

17.6666666667

18

18.3333333333

18.6666666667

19

19.3333333333

19.6666666667

20

20.3333333333

20.6666666667

21

21.3333333333

21.6666666667

22

22.3333333333

22.6666666667

23

23.3333333333

23.6666666667

24

24.3333333333

24.6666666667

25

25.3333333333

25.6666666667

26

26.3333333333

26.6666666667

27

27.3333333333

27.6666666667

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28.3333333333

28.6666666667

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29.3333333333

29.6666666667

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30.3333333333

30.6666666667

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31.3333333333

31.6666666667

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32.3333333333

32.6666666667

33

33.3333333333

Sheet1

Minimum Vegetation Clearance (feet)Voltage (kV)

10.050 or below

10.360

10.770

11.0804.00190

11.3900.3376

11.710010.336.3333333333

12.0110

12.3120

12.7130

13.0140

13.3150

13.7160

14.0170

14.3180

14.7190

15.0200

15.3210

15.7220

16.0230

16.3240

16.7250

17.0260

17.3270

17.7280

18.0290

18.3300

18.7310

19.0320

19.3330

19.7340

20.0350

20.3360

20.7370

21.0380

21.3390

21.7400

22.0410

22.3420

22.7430

23.0440

23.3450

23.7460

24.0470

24.3480

24.7490

25.0500

25.3510

25.7520

26.0530

26.3540

26.7550

27.0560

27.3570

27.7580

28.0590

28.3600

28.7610

29.0620

29.3630

29.7640

30.0650

30.3660

30.7670

31.0680

31.3690

31.7700

32.0710

32.3720

32.7730

33.0740

33.3750

33.7760

Sheet1

Minimum Vegetation Clearance (feet)

Line Voltage in kilovolts (1000 volts)

Minumum Vegetative Clearances in Feet

Seattle City Light Minimum Vegetation Clearance

Sheet2

Sheet3

Importance of Regular Cycle Maintenance

- “Deferral of line clearance beyond an optimal cycle can result in increased costs…of 23% - 70% per unit” (2009 ACRT assessment).

- 71% of (distribution) trees are “medium” or “fast” growing species

-In 2006 after several years of not funding Veg. Mgmt we had over 875 outages due to vegetation, mostly trees. Since then the average has been about 182 outages/year.

SCL Urban Forestry:Urban Tree Replacement Program

• Partners with Trees for Seattle and SDOT on tree planting/establishment projects

• Partners with Washington State Nursery and Landscape Association (WSNLA) to provide Urban Landscape Tree Replacement Certificates in Franchise Cities

SCL Urban Forestry• “Right Tree Right Place” information and customer care

– Average 1600+ calls/emails per year

• Maintains National Arbor Day Tree Line USA designation since 2013

• Special Projects: - Cambistat pilot, - Green Line Transmission Corridor Community Stewardship pilot,

- PLC Standards update, - 4 kV Substation Vactor-ing pilot

Landscapes Maintenance - 16 Major Substations

- Neighborhoods- Showpiece Landscapes- Landmark Building

Designs

- Over 75 Properties- Decommissioned Subs- Service Centers and

System Operations Center- Other Facilities

- Restoration Projects

Landscapes Maintenance

THANK YOU!

QUESTIONS?David BayardPower Line Clearance and Landscapes ManagerSeattle City LightPh: 206-386-1902David.Bayard@Seattle.Gov

Power Line Clearance and Landscapes UnitIntroductionSeattle City Light system overviewGeneration – Transmission - DistributionSeattle City Light System OverviewOrganizational ContextOrganizational ContextSeattle City Light’s �Power Line Clearance and Landscapes UnitBudget #s (2018)Distribution Tree Trimming ProgramTypical Distribution System Facilities Dist Tree Trim MethodologySlide Number 13Transmission Right-of-Way Maintenance Program Transmission Right-of-Way Maintenance Program Transmission Right-of-Way Maintenance Program Importance of Regular Cycle Maintenance�� - “Deferral of line clearance beyond an optimal cycle can result in increased costs…of 23% - 70% per unit” (2009 ACRT assessment). ��- 71% of (distribution) trees are “medium” or “fast” growing species ��-In 2006 after several years of not funding Veg. Mgmt we had over 875 outages due to vegetation, mostly trees. Since then the average has been about 182 outages/year.SCL Urban Forestry:�Urban Tree Replacement ProgramSCL Urban ForestryLandscapes Maintenance Landscapes Maintenance Slide Number 22