New PNNL Report Aids Utilities in Preparing for Wildfires

Every year, wildfire threatens lives, homes, and the nation’s power grid. In rare cases, power infrastructure itself can ignite fires, which can lead to power shutoffs for millions of customers. Although just 3 percent of wildfires are caused by power grid equipment, these fires can cost billions in economic losses and long-term recovery actions. 

To help utilities across the nation better prepare to combat wildfire risk, researchers at the Department of Energy’s (DOE’s) Pacific Northwest National Laboratory (PNNL) published a report that describes what utilities are already doing to bolster their systems against both igniting wildfires and also from wildfire damage itself. 

The report, titled “Current Best Practices on Wildfire Risk Reduction for Electric Transmission and Distribution Systems,” was funded by DOE’s Grid Deployment Office as a response to Executive Order 14308, Empowering Commonsense Wildfire Prevention and Response.

“We hope that utilities can use the new report as a ‘menu’ of sorts to choose mitigation tactics that work best for their particular needs,” said Andre Coleman, a chief scientist at PNNL and lead author on the report. “We understand that not every utility has access to the same resources, that there is no one right way to combat the wildfire threat.”

Both transmission and distribution infrastructure can cause wildfires.

At the distribution level, fires are more likely because power lines are usually in closer contact with the ground or vegetation and have more points of failure. What’s more, there are many more miles of distribution lines in the United States (around 6 million miles) compared with transmission lines (around 700,000 miles). 

However, because transmission lines carry a much higher voltage, fires caused by transmission lines can become more catastrophic. What’s more, transmission lines often stretch across remote, rugged terrain, which means wildfire ignitions may not be discovered quickly.

The report breaks down mitigation efforts in three stages: before, during, and after a wildfire.

Before and during a fire

Long before environmental conditions become ripe for fires, utilities can prepare. Across the United States, utilities inventory and monitor the health of their equipment, including poles, towers, transformers, capacitors, resistors, and more, to make sure everything is operating appropriately. 

Wildfire monitoring and modeling is also a key practice among utilities. 

“Monitoring the environment around power lines and other infrastructure can tell a utility how hot, dry, or windy conditions might converge to produce fuel for a potential fire,” Coleman said. “Utilities also use wildfire simulations to model how a fire might spread through their service territory.”

In some cases, utilities with the resources to do so have chosen to bury power lines underground to reduce the risk that those energized lines could touch vegetation and ignite. However, transmission lines can’t be buried, so utilities have turned to technologies such as highly sensitive fault-detection sensors. For example, fast-trip settings allow circuit breakers to trip much quicker than standard settings, preventing ignition of nearby vegetation.

After the fire

Once a fire has been extinguished, utilities need to take steps to assess damage, eliminate safety hazards, and restore power as quickly as possible. One example is post-fire vegetation management, such as removing fire-affected trees that can pose fall risks. In planning for the future, utilities can also consider planting low-growing or fire-resistant plants.

Utilities also assess the performance of their monitoring, modeling technology, and decision-making after fires to evaluate their effectiveness. These performance metrics include outage duration, number of affected customers, and customer notification success rate.

Next steps

Developing effective wildfire management plans for before, during, and after a fire is not an easy or straightforward task. Individual utilities differ in resources available to them, how many customers they serve, what kind of terrain their equipment is built in, and how much money they can spend to pursue any mitigation plans. 

“Each utility has to address its own situation in terms of cost, capacity, and regulatory requirements that can’t be considered in just one report,” Coleman said. “Some utilities might seek federal or state funding for assistance to implement these best practices. And for many of these utilities, it may take a series of investments over a longer period of time as resources are available to do so.” 

But technology is improving, and researchers are looking into various ways to both reduce the number of utility-caused wildfires and to develop standards to assess their wildfire mitigation systems. For instance, ongoing research into applying artificial intelligence and machine learning is helping utilities better improve wildfire predictions. One team developed a machine learning model that could predict what segment of the utility network might need to be de-energized based on sustained wind speed and gusts. Another team approach incorporated not just meteorological data but also vegetation characteristics, population density, and topography of the surrounding area to determine fire risk. 

“The best practices in this report not only reduce the risk to utility and ratepayers but also have broader positive impacts on the general public and the nation’s economy,” Coleman said.

PNNL has collected utility wildfire mitigation plans in an online repository and analysis platform, which can be found here.