The Link Between Power Lines and Wildfires

Explore the critical relationship between power lines and wildfires. Learn about prevention strategies, and risk mitigation with expert guidance from the WFCA.

Between 2016 and 2020, electrical power networks caused 19% of the wildfires that occurred in those five years. With the growing risk of wildfires amid climate change, there is heightened concern about electrical power conductors igniting wildfires. ¹

How Can Power Lines Spark Wildfires?

Power lines can ignite wildfires in several ways, all of which can be prevented through proper mitigation tactics. Here are the most common ways wildfires are sparked from power lines:

Downed Lines: Power lines can fall for many reasons. Whether it’s caused by a falling tree or strong winds, it remains energized until the utility company shuts it off. In hot and dry climates, the surrounding vegetation that the line comes in contact with can spark a fire.²

Vegetation Contact: As already mentioned, dry vegetation on the ground that comes in contact with an energized downed power line can spark a fire, but this can also occur with intact power lines. When a tree becomes overgrown and its branches expand and reach the power lines, a fire can ignite. A tree branch lying between two conductors can also produce high-temperature electrical arcs.²

Conductor Slap: Power lines are strategically spaced apart to prevent them from coming into contact with one another. In the case where wind or other outside factors occur and the lines do come into contact, this is known as a ‘conductor slap’. When a conductor slap occurs, it creates high-energy sparks and spits out hot metal particles that can start a fire on the ground.³

Repetitive Faults: In some cases, it only takes one fault to ignite a fire, in other cases, the fault may go undetected until a fire is ignited. An example of repetitive faults can be low-hanging branches touching a powerline for an extended period or wind causing the powerlines the repeatedly hit against one another causing a conductor slap.

History of Wildfires and Utility Companies

In 2007, San Diego County faced devastating wildfires, including the Guejito, Witch, and Rice fires, which burned 207,000 acres, destroyed 1,141 homes, and killed two people. Investigators found that the fires ignited when vegetation, was not properly cleared and contacted power lines and cables from San Diego Gas & Electric (SDG&E) and Cox Communications. Although SDG&E did not admit liability, they paid over $2 billion in settlements, while Cox Communications paid $444 million.²

Similarly, equipment developed by Pacific Gas and Electric Company (PG&E) has been linked to multiple wildfires in Northern California. In April 2017, the utility was fined $8.3 million for failing to properly maintain a power line that caused the 2015 Butte Fire, which killed two people and destroyed 549 homes in Amador County. PG&E still faces over 1,000 lawsuits related to this fire, and CalFire is seeking $90 million for firefighting costs.

Additionally, PG&E was found guilty of 739 counts of negligence for the 1994 Rough and Ready wildfire, resulting in $30 million in penalties from California state regulators.²

These events underscore the importance of proper vegetation management and infrastructure maintenance to prevent such disasters.

What Can Utility Companies Do To Mitigate Risk?

Utility companies are taking proactive steps to mitigate wildfire risks exacerbated by climate change. Popular solutions to mitigate the risk include rigorous vegetation management, undergrounding distribution lines for resilience, deploying advanced digital solutions for predictive maintenance, and investing in innovative grid modernization research.⁴

How Are Public Safety Power Shutoffs Implemented?

Implementing Public Safety Power Shutoffs (PSPS) involves complex decision-making by utility companies, particularly in regions prone to wildfires, such as the western United States. The decision to shut off power relies heavily on weather forecasts indicating high winds and dry conditions, which significantly elevate fire risk.

Despite these risks, utilities must weigh the potential consequences of power outages, such as impacts on public health, essential services like water supply and medical devices, and overall community resilience. Balancing these considerations involves integrating technologies to enhance awareness. This is done through early detection of fire risks, maintaining infrastructure, and exploring options like undergrounding power lines where feasible. Ultimately, the challenge lies in finding a delicate balance between mitigating fire hazards and maintaining essential services crucial to public well-being.⁵