Mother Nature tends to have a mind of her own. Utility power lines are vulnerable to damage from severe storms—particularly fallen trees and limbs, which can lead to power outages. About 50% of outages are caused by overgrown vegetation, which is why electric utilities regularly trim and maintain their local systems.
This starts with significant on-the-ground labor, including manual data collection, as workers assess the vegetation that needs to be cleared while walking below the infrastructure. Following the trim work, manual verification of its quality and completion is required.
This has been the standard approach for the past few decades. But as extreme weather events increase and digital tools improve, electric utilities are looking to innovative vegetation management methods to improve power reliability for consumers.
With the help of technology, utilities may be able to dispatch trimming crews at the ideal moment and location, preventing additional outages while enhancing productivity, cutting costs and providing better service.
Timely monitoring can help identify infrastructure susceptible to damage. Finding the right technology makes this process more efficient.
Each vegetation management tool has advantages.
Lidar—which stands for light detection and ranging—gives exact, 3D data about the shape of the surface around utility assets. Lidar is a popular way to scan portions of forests to determine the height of trees. The technology doesn’t generally assess plant health but can pair with high-resolution multispectral satellite imagery to help define areas of need.
Satellites provide coverage 24 hours a day and can supply two kinds of images: a wide view of the area near utility assets and a more detailed micro view. Satellite data can often be used in place of other monitoring methods.
With satellite technology, utilities can learn a lot about local vegetation, including:
- Health. Information gathered makes it possible to predict vegetation growth based on real conditions.
- Dryness. This information is valuable for determining the likelihood of a wildfire and how to protect utility infrastructure.
Satellites are always in orbit around the Earth, so data can be updated quickly, in real time. This makes it possible to respond swiftly and precisely.
Today, satellite images can have a spatial resolution to within 1.6 feet, making it easy to spot when vegetation grows in the rights-of-way near power lines and utility equipment.
Typically, satellites speed up the process of inspecting power lines because they provide information for making data-driven decisions about vegetation management.
Electric utilities can also use fixed-wing aircraft and drones to monitor and control the growth of trees and plants near power lines. Drones fly close to equipment, take clear images and provide data to help show how close vegetation is to equipment and check the health of trees.
Many utilities use drones with cameras.
When it comes to taking care of surrounding vegetation, drones are often used for detailed surveys rather than large-scale monitoring like satellites.
Once lidar or satellites—often together—have collected data on a large amount of vegetation near power lines, drones can be used to inspect a single area and do all the necessary checks.
Public power utilities place a high focus on vegetation management. It is the most crucial tool for reducing the likelihood of power outages. A thorough understanding of the vegetation’s past, present and projected future is essential for a successful approach to reducing these risks.
The growth of lidar, drone and satellite data presents an opportunity to close the loop with continual data-driven vegetation management intelligence and increase the power line system’s dependability and safety. In the end, all three technologies for managing vegetation serve different purposes, and electric utilities choose the options that work best for them.
Think Ahead When Planting a Tree
By Scott Flood
“Why can’t they just leave my trees alone?”
Electric utilities are required to document that every piece of equipment and every foot of their power lines are a safe distance from trees and other vegetation. If a tree-trimming crew visited your home, it was likely because your trees were closer to power lines than the rules allow, and your electric utility is legally required to act.
The last thing your utility wants to do is alter or remove a prized part of your landscaping. It would rather help you avoid conflict between electricity and greenery altogether. How? By reminding you to plant your new trees, shrubs or other vegetation where they won’t grow into power lines or other electric equipment.
Whether you want to plant a tree, a decorative shrub or something else, it’s helpful to consider how it will grow during the next 20 or 30 years. Consider the eventual height and how wide the canopy of branches is likely to spread.
For example, even small trees and shrubs should be planted at least 20 feet from power lines. If you can’t plant that far away, make sure you choose a species that won’t top out at more than 15 feet high.
Trees that will be 40 feet high or less should be at least 25 feet from electricity. Larger trees should be at least 50 feet away.
Thinking about what’s above the ground is only part of tree-planting safety. Before you grab a shovel and start digging, contact 811 to make sure you won’t accidentally cut into any underground utility lines. The service sends people to your property to mark the approximate locations of utility lines. Because it can be challenging to pinpoint exact locations, use only hand tools when digging within a few feet of the markings.
Trees aren’t the only type of vegetation requiring thoughtful planting. If there’s a pad-mounted transformer in your yard, you might be tempted to hide it behind colorful flowers and neatly trimmed shrubs.
Unfortunately, if there’s a problem, crews need clear access to the transformer. That’s why it’s always a good idea to keep plantings at least 10 feet from the transformer’s doors and at least 4 feet from its sides. Otherwise, crews responding to a power problem may need to remove part of your landscaping.
Finally, if you notice your trees or other vegetation have grown dangerously close to power lines or equipment, don’t try to trim them on your own. Let your local electric utility know, or hire a professional arborist. Tree trimming is more dangerous than most people realize, and you don’t want to find yourself in an emergency room—or be the person who plunges your neighbors into the dark.