When orchard trees meet power lines, disaster can result. Whether it’s a power outage affecting millions or the accidental death of a line worker, such scenarios can have devastating and far-reaching consequences:
Ø In 2003, sagging power lines contacted untrimmed walnut trees in Ohio and caused a massive cascading outage – costing millions and leaving entire cities without power throughout parts of the Northeastern and Midwestern United States, and the Canadian province of Ontario. The incident left millions without power – and came at a great cost to state coffers.
Ø In Fresno several years ago, a grower used a boom lift to prune his orchard. When wires from the power line became entangled in the lift, he was electrocuted.
Ø In another California orchard, a fast-growing nut tree grounded to a high-voltage power line, causing widespread chaos and power loss throughout the region.
Unfortunately, these events are far too common. The good news? When Pacific Gas and Electric Company (PG&E) and growers work together, we can prevent these losses and tragedies.
Growers need only contact PG&E at 1-800743-5000 or at email@example.com early in their planning phase – before they plant new trees. One call or email is all it takes to eliminate the risk of tree removal and gain some valuable peace of mind.
PG&E also offers a Mature Orchard Incentive Program for Transmission Lines, which encourages orchard growers to remove nut-bearing trees under transmission lines. Growers can use the incentive to replant crops that are compatible with electric transmission lines or reinvest the funds according to their needs.
Public Safety, our Priority
As a utility provider, our most important responsibility is to ensure public safety and provide a reliable supply of electricity. To meet those obligations and state and federal regulations, we must maintain safety clearances between trees and other vegetation and our high-voltage power lines.
The electrical charge carried by high-voltage lines is many times more powerful than the current that flows through standard power lines. Naturally, the potential for life-threatening injuries is commensurate with that power.
For those reasons, we take great care to regularly inspect our transmission lines for potential hazards, using ground patrols as well as aerial remote sensing.
Each year, PG&E is required to inspect all electric transmission and distribution lines across our 70,000-square mile service area. Our inspections are audited, and we will be fined if we fail to comply with required standards for vegetation clearance.
Multiple Risks at Play
Electricity from power lines finds its way to the ground using nearby objects. Like lightning, it can jump to a building, a person or a tall tree. Electrical storms and lightning strikes can also lead to a voltage surge, which may create an electrical arc that travels to nearby objects like trees, vegetation and people.
When trees or vegetation are located near high-voltage power lines, they pose serious fire and electrical hazards. Anyone on the ground is at risk – whether they are in contact with the power line or just standing near the tree.
And when a tree trimmer or a child climbs or shakes that tree – or when the tree contacts a power line – the risk to lives and property is multiplied, often with tragic consequences.
Reasons for Generous Clearance
We understand that growers need to plant every possible acre, and that some consider our clearance requirements excessive. But our requirements are based on many decades of field experience – and the fact that a variety of conditions can create dramatic material changes in towers and power lines.
High-voltage power lines also require more clearance than other power lines because of their current strength and potential hazards. In addition, clearance requirements must account for the real possibility of line sag, which depends on weather, line design and electrical load.
Metal transmission conductors can expand in hot conditions, sometimes causing wires to sag. Wind and ice storms can also wreak havoc, loosening normally taut wires and causing branches or trees to fall into electrical lines.
During hot weather, power lines carrying heavy electrical loads can become heated, causing them to stretch out. These elongated lines can sag near the ground or near trees and other objects.
As a result, what appears to be generous clearance in winter months may not be enough in the heat of summer.
Tree Growth Exceeds Expectations
Our mantra – “plan before you plant” – is not a new message. Yet it isn’t accepted by some growers, despite its potential to benefit their operation and their community.
Some growers question whether their young trees could ever interfere with power lines that soar 40 or 50 feet – especially when tree purveyors provide assurance that their stock will top out at 20 or 25 feet.
But plantings routinely exceed their expected growth rate and height. We’ve experienced trees that have grown 12 feet in a single growing season.
Other growers fail to notify PG&E because they misunderstand the nature of our easement on their property. They may believe the electric easement right-of-way for vegetation applies only to our wires in the air, when it actually extends across a grower’s physical property.
It’s also human nature to hope for the best – or to think “it can’t happen to me.” In fact, one of the state’s largest nut producers learned through trial and error that power lines and orchard trees don’t mix. Today, he contacts us regularly before planting.
Every orchard is vital to the economic health of our state. By working together, we can prevent injuries and power outages, and preserve more trees.
Contact PG&E at 1-800-743-5000 or at firstname.lastname@example.org so we can identify power-line friendly planting locations that avoid transmission lines. We’ll be out to your orchard within days, at no cost to you. — By John Bolling, Orchard Vegetation Program Manager, PG&E