1. Vegetation Management
Pacific Gas and Electric Company
System and
San Francisco County Overview
Presented by Joel Smith / PG&E Forester Area 1 Vegetation Management

2. Transmission Substation Distribution Substation
Basic Electric System
Power Plant
Transmission Substation
• Nuclear
• Hydroelectric
• Geothermal
• Natural Gas
Power Generated at kV
Transmission Line
60, 115, 230 or 500 kV
Possible NERC regulation
Distribution Line
4, 12, 17 or 21 kV
Business
Home or Business Volts
Distribution Substation
Home

3. Compliance Requirements
PRC 4293 – Utility Vegetation Management - Tree Pruning/Removal
Maintain 4 feet of clearance between trees and primary distribution power lines and 60/70 KV transmission lines
Maintain 10 feet of clearance between trees and all transmission lines 115 KV and above
Remove dead, diseased, defective and dying trees that could fall into the lines (facility protection trees)
PRC 4292 – Utility Vegetation Management – Pole Clearing
Clear 10’ x 8’ cylinder around the base of subject poles and transmission structures
Remove dead vegetation up through the primary conductor level
CPUC G.O. 95 Rule 35 – Utility Vegetation Management – Tree Pruning/Removal
Maintain 18 inches of clearance between trees and primary distribution power lines and 60/70 KV, greater clearances for higher voltages
Remove facility protection trees (as defined above)
Address situations where trees cause strain or abrasion on secondary conductors
NERC Standard FAC – Vegetation Management Requirements for Transmission
Minimum Clearance Standard based on voltage class
Zero tolerance for vegetation caused outages

4. California Regulations for Distribution Lines
GO-95 Rule 35
PRC 4293
PRC 4292
18 in.
18 in.
4 ft.
HIGH VOLTAGE
4 ft.
8 ft.
10 ft.

5. Routine T&D Vegetation Management Program Scope
Address through trim or removal, any tree that will encroach within minimum clearance distances and any hazard tree to maintain regulatory compliance.
113,00 miles of distribution line
19,500 miles of transmission line
70,000 square mile service territory
Trim or remove over 1.2M trees per year
5M trees in inventory with potential to “grow into” conductors
50M trees with potential to “fall into” conductors
Maintain fire breaks on 120,000 subject poles
Maintain transmission right of way

6. Zone
Tree Population
Trees Worked Annually
Wire 5m
1.1m
Border
7-10m
50k
Fall
40m
30k

7. PG&E Distribution Tree Trimming
The Routine Patrol Standard – Defined Scope of Work
The Annual Patrol: Inspect 100% of overhead line, identify and clear only trees that will encroach before next cycle.
Aggressively target trees up to 12” DBH, palms, and fast growers for removal
Pruning for 2 to 3 years clearance
Hazard trees
Strain or abrasion on secondary lines
Pruning Standards – Utility Pruning BMP
600+ contract tree crews
350+ utility arborists/foresters
Approx 60 PG&E office and field personnel

8. Territories

9. Tools 1) Right Tree Right Place 2) Work Practice 3) Emergency
• Inspection, pruning and removal
• ROW and NERC Standards
3) Emergency
Operations

10. Tell me what’s missing…
3-dimensionsal clearance requirements for electric power lines
Expectations of arborists as to growth rates of specific trees in specific habitats
Contract tree trimmers remove enough vegetation to ensure minimum clearance distances remain in place by time of next scheduled trimming
Validated annually and projections modified based upon climate, weather, and other factors of relevance to arborists
Random sampling audits annually ensure that initial trimming is sufficient to prevent contact 10

11. Customer Interface
Consistent graphics and language to comprise our educational presence across all communication channels to both internal and
external audiences.
PG&E’s customer interface program during the early years was quite fragmented with no visible branding.
At times there were permanently assigned public education

12. City challenges… 230 Magellan

13. 19 Maywood

14. 217 Tocoloma

15. 240 Casitas

16. “If a tree falls in the City, and there is no one there to hear it, will it still…hit a car?”

17. Contact Information
Joel Smith, Forester (local project manager)
San Francisco and San Mateo Counties
Office
Cell