Almost everyone has at some point in their life experienced an electricity blackout. When a blackout occurs, it is usually sudden. Our reaction is to become annoyed due to the interruption of our favorite episode of a tv show, or that carefully planned dinner party you were having. It is unlikely that one would ever think about blaming vegetation management within utility rights of way.
What is the relationship between electricity and vegetation?
Electricity in the United States is transported from generating facilities to local distribution substations through a grid of high-voltage transmission lines that is over 160,000 miles long. Along the way, the electrical grid must go through areas dominated by vegetation. Consequently, some level of vegetation management is necessary to ensure that the high-voltage transmission lines function without disrupting the flow of electricity.
Some of the reasons why vegetation management around utility components is critical include:
- Reducing the potential for fire due to the collection of organic debris.
- Removing the potential for vegetation to interfere with electrical equipment and cause power outages.
- Eliminating habitats for wildlife that could affect utility equipment.
- Improving worker safety.
- Providing clear line of sight for equipment inspection and maintenance.
- Providing adequate ventilation to prevent build-up of heat or humidity that could affect functioning of utility equipment.
- Preventing vegetation from covering or hiding fences that are in place to reduce unauthorized entry.
What is the cost of utility vegetation management?
- It is estimated that utility companies spend $6 – 8 billion annually on clearing vegetation from overhead lines.
- The impact of unmanaged vegetation can be devastating. For example, in August 2003, the largest electricity blackout in the United States and Canada happened when powerlines and trees came into contact with each other in Ohio. The short circuit that led to the blackout affected 50 million people, was connected to at least 11 deaths and had an estimated cost of $6 billion.
- Some of the costs related to invasive vegetation management can be attributed to managing vegetation around utilities. According to the US Fish and Wildlife Service, invasive species cost the United States nearly $120 billion in damages to the ecosystem each year.
Kudzu is a climbing perennial vine that is invasive, fast-growing, and can outcompete everything from native grasses to fully mature trees.
Kudzu often climbs up the wire and pole supporters of the electrical transmission lines.
The weed either weaves into the hot wire or causes the pole to fall, causing an interruption in the power supply.
Poison ivy is a toxic vine that can climb to heights of up to 60 feet high, or sometimes appear as a low, upright shrub. Poison ivy causes an allergic reaction to an oily resin contained in the plant. The oily resin easily attaches to skin, clothing, tools, equipment, and pet’s fur. You can get an allergic reaction from touching the plant, contaminated objects, or if you inhale smoke from burning poison ivy plants.
There are numerous plants, other than kudzu and poison ivy, that invade utility vegetation and require special attention, thereby adding to the cost of utility vegetation management.
Are there some guidelines for utility vegetation management?
First, utility vegetation management is the largest preventative maintenance expense for utility providers in the United States.
Second, the Federal Energy Regulatory Committee (FERC) establishes regulations and oversees utility providers who are required to maintain constant clearance between trees and electrical transmission lines. The utility providers must create vegetation management plans that adhere to state and local requirements. If utility providers do not comply, they can be fined.
Third, following the 2003 blackout, the FERC assigned the North American Electric Reliability Corporation (NERC) with the responsibility to develop and enforce standards to ensure the reliability of the Bulk Power System. Furthermore, the NERC enforces the Reliability Standard that addresses vegetation management covering tree trimming on rights of way.
Now that we have seen how the federal government oversees the entire process, the next questions are
- How is utility vegetation management accomplished
- Who does the work?
What are the best practices of utility vegetation management?
There are a variety of methods used in utility vegetation management. These include hazardous tree removal, brush removal, tree pruning and herbicide application.
Hazardous tree removal
When a tree is unhealthy and has the potential to fall on powerlines, the tree must be physically removed. This will prevent the tree from hitting powerlines, causing blackouts, and/or wildfires.
Brush removal is important because of low-lying brush that has the potential to cause outages and fires. They can also limit access of line crews to powerlines when they are inspecting them.
Tree pruning involves the maintenance of healthy trees that have the potential to grow close to powerlines. Tree pruning helps guide tree branches away from powerlines and reduces internal decay of trees.
Herbicides are used to kill off unwanted vegetation. Herbicides have been proven to greatly reduce the cost and environmental impact of maintaining utility rights of way. In fact, herbicides have been a key method for controlling vegetation along utility rights of way. If herbicides are not used, the costs associated with utility vegetation management may double.
The major success of herbicide usage is because they allow utilities to manage vegetation while it is low, rather than having to deal with tall vegetation later on.
Even though herbicide use is the most cost-effective utility vegetation management technique, it does come with some challenges. Public concern about environmental contamination has initiated a push for alternative methods to control unwanted vegetation. Specifically, herbicide residues are being found on a regular basis in storm, ground, and stream water, which has increased the amount of exposure for humans and the environment.
To optimize herbicide use in utility vegetation management, applicators need to:
- Understand the target species biology and ecology. This is information about a species that allows the applicator to apply the herbicide at a time when the target species is most vulnerable. For more information checkout the following article: https://brewerint.com/agriculture/pest-biology-and-ecology-on-your-land/.
- Be knowledgeable about the chemical mechanism of the herbicide. For maximum control, the applicator must match the target species with the appropriate herbicide, while ensuring non-targets and the environment are not harmed.
- Be familiar with the different factors that will influence the effectiveness of foliar herbicide spray applications. For example, using an adjuvant which will reduce the potential for herbicide spray drift. Additionally, it will also reduce the likelihood of the herbicide drifting off of your target target and harming other organisms and the environment.
How are the best practices of utility vegetation management implemented?
Successful utility vegetation management starts with the establishment of a long-range management plan. These plans should consider the economics, effectiveness, environmental impact, and public perception of the methods used. Additionally, potential control methods need to pose minimal risks to workers, nontarget organisms, and natural resources.
Utility providers work with vegetation management contractors to design vegetation management plans. The goal of a vegetation management plan is to maintain acceptable appearance of the right of way and minimize erosion. Inhibiting the re-establishment of target tree species by encouraging the development of ground cover and low shrubs is also an additional goal of a vegetation management plan.
Ultimately, vegetation management plans must seek to:
- Accomplish set objectives in a cost-effective manner with appropriate regard for worker safety.
- Protect public health and the environment from unreasonable adverse effects.
- Follow all applicable local, state, and federal laws and regulations.
Utility vegetation management must be taken seriously and is more than just trimming trees. It is about making powerlines safe for everyone. Utility providers are legally responsible for ensuring the rights of way are well-maintained. They must also consider both the financial and moral consequences.
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