How to prevent power lines wildfires

For the past years, utilities in the US have had to ensure damages to the transmission and distribution lines related to wildfires, particularly in the traversed wilderness areas.

Today, there are some pieces of evidence that power lines sometimes trigger wildfires. High winds sometimes blow nearby branches or trees into power lines, which starts fires. In some instances, those winds snap the distribution line poles, resulting in falling live wires onto nearby dry grass and then sparking fires.

Destructive Wildfires Over the Several Years

Wildfires exist in different states, but California has the most serious problems, particularly over the past years. Record-breaking wildfires have turned millions of forest acres into ashes.

For example, in late 2017, Pacific Gas and Electric (PCG.N) power lines were blamed for a dozen of wildfires and 18 associated deaths in Northern California. According to the California Department of Forestry and Fire Protection report, these wildfires were caused by the branches and trees that came into contact with those power lines. 

The Redwood Fire resulted in 9 civilian deaths, destroyed over 500 structures, and burned more than 36,000 acres. As for the Atlas, Fire resulted in 6 civilian deaths, destroyed over 700 structures, and burned 52,000 acres. 

In the summer of 2018, the Department reported a minimum of 17 more fires triggered by power lines. The Thomas Fire was triggered by the Southern California Edison lines that killed over 20 people and destroyed 1,000 structures.

The Camp Fire is considered the state’s worst fire in history; that destroyed 14,000 homes and killed at least 85 civilians. The wildfire’s exact cause was initially undetermined, but it started near the PCG.N transmissions lines, where a 15-minute outage was experienced before the start of the fire.

Can Burying of 10,000 Power Lines Solve the Wildfire Problems?

PCG.N announced in July 2021 that they plan to bury 10,000 miles of power lines as a safety measure in high-risk fire zones after their power lines caused a number of destructive wildfires over the past years.

According to the California power company, the utility keeps over 25,000 miles of overhead distribution power lines, particularly in areas with the highest fire risk. It is equivalent to over 30% of its total distribution overhead system.

A few days later, when the company’s power lines were involved in the Sierra Nevada wildfire, they proposed that solution to prevent wildfires in the future. In 2020, they emerged from bankruptcy and sought protection from creditors after wildfires in 2017 and 2018 drove the potential liabilities of the utility into billions of dollars.

The company said, "Following the devastating October 2017 Northern California wildfires and the 2018 Camp Fire, PG&E began to evaluate placing overhead power lines underground as a wildfire safety measure," 

California officials developed a six steps oversight process that will help hold the power lines accountable if they fall short on safety measures as part of the power company’s exit from bankruptcy. On the other hand, the officials voted to toughen the company’s oversight in April, saying that the power lines largely underperform in the required tree-trimming near the utility in areas with wildfires' highest risk.

After announcing Butte County's new safety initiative, the company has served over 16 million people across the 70,000 sq miles in Central and Northern California.

Undergrounding or burying power lines helps lessen public safety power shutoff needs. During windy conditions, it is the last resort that can reduce the risk of branches or trees touching live power lines and starting destructive wildfires in the area.

Other Ways to Prevent Wildfires in the Future 

Power lines can cause wildfires through different mechanisms: downed lines, conductor slap, recurring faults, and component failure.

Downed Lines. A single energized line conductor can possibly break and fall to the ground, and a surface contact resistance can lead to restricted fault current flow. Too low a current will fail to trip a circuit breaker or blow a fuse. Then, the line remains energized for extended periods, which causes high-temperature and high-energy arching that can ignite anything in the area.

Conductor Slap. Conductors are sometimes susceptible to slapping together. As a result, high-energy arching is created, and hot metal particles are ejected that can start a wildfire.

Recurring Faults. Conductor slap, vegetation, equipment failure, etc., can cause some power line faults several times. If these faults are repeated, they can cause fires.

Component Failure. The time will come when power line circuits with hundreds to thousands of components will fail. However, they undergo a pre-failure period to serve load before they fail continuously. During that period, arching and sparking may occur, leading to fires. 

Aside from undergrounding wires, here are other measures to make the current power systems safe and does not cause wildfires:

Power Lines and Wires Insulation 

Overhead transmission lines can be insulated by ceramic, phenolic, and other insulating materials from the support towers. It is also advisable to insulate the ground by air because of its easy availability and low cost, and the high-tension wires from each other. It is advantageous to insulate underground transmission cables using different materials, like oil.

Old Wooden Poles Replacement 

The power company should check the wooden poles if they already need some replacements. They can replace old wooden poles with steel ones to fire-harden the lines in wildfire-prone areas. Not only that, steel poles are known to produce lower greenhouse gas emissions and energy resource impact.

Biomass Energy 

Biomass energy helps prevent wildfire and reduce greenhouse gas emissions by promoting less forest fuel use. Remember that biomass waste is usually disposed of by burning, leading to warming and polluting the environment.

Meanwhile, if biomass is used for fuel, it can solve both problems. In California, biomass energy is part of the renewable energy goals, where forest fuels are used in the power plants.

Pre-planned Power Outages 

While power outages sound uninteresting to households, pre-planned power outages help prevent wildfires during extreme fire risks. Deliberating this action during windstorms is already part of San Diego Gas and Electric Co’s safety measures. It may cause inconvenience to the consumers, but it can save them from destructive events later on.

If power companies take action to prevent wildfires, among other things, by undergrounding or burying power lines and using underground utility map that could address gaps, inconsistencies, incompatible formats, risks of misinterpretation, logistical obstacles and by that might prevent next wildfire so people can gain peace of mind during extreme windstorms. 

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