…Is PG&E The Scape Goat? Part 2. …
Energy is locked up in any energized electric wire or circuit, and the amount of energy depends on the voltage, with higher voltages resulting in the release of greater amounts of energy when wires are shorted or circuits are grounded.
Whenever an energized electric wire touches ground or is short circuited, such as when two energized wires cross, it will create an arc or spark. When an energized circuit is interrupted, such as by a circuit breaker or fuse, it can create an arc, the higher the voltage, the greater the arc.
When an electric arc or spark touches flammable material, it can ignite that material.
These are “absolute givens” and must be protected against.
It is why the trimming of trees and the clearance of brush and flammable materials is so important.
The less moisture in the flammable materials the more likely they will ignite which is why dead trees, such as those killed by insect infestations, and dead brush are especially dangerous.
California’s rules for trimming and clearance are illustrated in the following composite. Note in many instances the required clearance is four feet.
Note also in E, that wires can be blown outside the foot print of the tower and that wires can sag as they become heated.
When PG&E wanted to increase clearance around its power lines to 15 feet on each side of the pole or transmission tower, the Sierra Club objected.
Quoting the Sierra Club:
“‘The California Public Utilities Commission requires PG&E maintain at least a 4-foot clearance between vegetation and power lines in high fire-threat areas year-round to help ensure electric reliability and public safety.’ Under their new program, PG&E wants to enlist property owner consent to voluntarily remove all vegetation to a distance of 15 feet from each side of the power lines in the affected zones, and extend the clearing down to one foot above the ground.”
“With the planned clearcut width of 30 feet, the path of destruction [from clearing] could be considerable.”
This establishes the political environment in which PG&E is operating.
Part 1 established that:
- There have been periods of drought in the past that did not result in destructive wildfires.
- Recent wildfires have become larger and more destructive.
- Policies to leave forests in their natural state allowed the buildup of dead trees which resulted in larger, more devastating fires.
Part 2 described the fundamental physics of arcing and sparking. Part 2 also established that PG&E’s attempt to widen tree trimming and brush clearing were opposed by environmentalists which defined the political environment in California.
This evidence supports the view that government policies were largely responsible for the recent large wildfires in California.
And that PG&E is being made the scapegoat for bad government policies.
. . .