Burying Power Lines Prevents Wildfires. But There’s a Cost

Investigators are eying the Lahaina wildfire as yet another deadly blaze started by electrical equipment. Putting lines underground would help—at a steep cost.
Altec crane holding worker fixing power lines
Photograph: PATRICK T. FALLON/Getty Images

Not long after the deadliest wildfire in modern American history swept through Lahaina, Maui, on August 8, speculation began swirling about a notorious igniter of out-of-control blazes: electrical equipment. 

Although investigators have yet to officially determine the cause of the wildfire, witnesses reported power poles snapping in the 60-mile-an-hour winds that were pouring down the nearby mountains, showering dried vegetation in sparks. And last week, the County of Maui hit Hawaiian Electric with a lawsuit, accusing the utility of neglecting its duty to power down its infrastructure, given the known risk of such high winds sparking wildfires. 

On Sunday, the utility responded with a press release, saying that at 6:30 am, a morning fire “appears to have been caused by power lines that fell in high winds.” Firefighters extinguished that blaze, the press release continues, but another fire popped up in the same area at about 3 pm, when the utility says its lines had been de-energized for more than six hours. That fire then spread into Lahaina. 

“Hawaiian Electric has now admitted to starting the Lahaina Fire on August 8th,” said John Fiske, the counsel representing the County of Maui, in a statement provided to WIRED. “In its recent release, issued Sunday night before the markets opened, Hawaiian Electric appears to have suggested there could be a possible second ignition source in the afternoon of August 8th without providing any supporting information.”

Investigators have yet to determine if there were two separate ignitions, or if the afternoon fire was a flare-up of the one earlier in the morning. Hawaiian Electric declined to answer questions for this story, referring WIRED to its press release.

If investigators ultimately conclude that the fire’s cause was electrical equipment, the Maui fire will join other recent city-razing blazes in the American West that were started—and then powered—by fierce winds rattling the power infrastructure. But even if utilities are able to prevent their equipment from sparking blazes—like by “undergrounding” lines, meaning enclosing them in piping and burying them in trenches—there are lots of other ways to start an epic conflagration on a warming planet.

Wind is essential to whipping up the biggest, fastest, deadliest wildfires. And electricity can be a dangerous add-on: If gusts down trees into power lines, or utility poles snap or fall over, all that jostling can send sparks into the vegetation below. Winds fan the growing flames, driving the blaze across the landscape with such speed that people in the way don’t have time to evacuate. (Strong winds also loft embers into the air, and can carry them perhaps 2 miles ahead of the main fire, creating new fires and making it harder for firefighters to manage.) Towns like Lahaina in the “wildland-urban interface,” where unkempt vegetation butts up against structures or intermingles with them, are especially vulnerable to such fast-moving fires. 

America’s aging grid wasn’t designed for today’s climate, with its warmer atmosphere, intense, longer-lasting droughts, and increasingly dry landscapes. So electrical-sparked, wind-driven fires are growing more destructive and deadly. In 2017 the Tubbs Fire destroyed over 5,600 structures and killed 22, and in 2018 the Camp Fire destroyed the town of Paradise and killed 85. In 2019, the California utility Pacific Gas and Electric, or PG&E, reached a $13.5 billion settlement for wildfires linked to its equipment, including both of these fires. Both have now been eclipsed by the Lahaina fire in terms of the human cost: At least 115 people have been confirmed dead, with hundreds still missing. 

For utilities, the calculus for whether to underground electrical infrastructure is more complex than you might think. PG&E has set out to underground 600 miles of its lines by the end of this year. By 2026, the utility plans to have 2,000 miles done. “Not only is it effective mitigation for wildfire risk, but it also actually provides the opportunity for reliability,” says Sumeet Singh, PG&E’s chief operating officer. 

Undergrounding means that during rainstorms, blizzards, and windstorms, the utility and its customers don’t have to worry about blackouts caused by trees falling on lines. And it could reduce the need for “public safety power shutoffs,” in which a utility proactively cuts electricity before the wind strikes. This is also a tricky calculation for a utility: They’re required by law to provide electricity—for critical infrastructure like wastewater treatment facilities, for businesses, and for people who rely on medical equipment—but also don’t want to spark a catastrophic fire.

But digging thousands of miles of trenches and laying lines comes at a steep cost. Singh says they started out at $5 million per mile, but are down to $3.3 million this year and are on track to shave off another half-million by 2026. The utility also doesn’t have to spend as much to maintain overhead wires and to constantly clear brush around equipment. 

Consumers end up footing the bill, either through higher electricity rates if a utility pays for the undergrounding, or with taxpayer money if the government subsidizes it. “That's one of the other unpleasant realities in the utility business, is that people end up paying for everything,” says Ted Kury, director of energy studies for the Public Utility Research Center at the University of Florida. “There's no such thing as the government pays. There's no such thing as the utility pays. People pay.”

Buried lines may be immune to the wind, but they’re not indestructible. Earthquakes can jostle that piping, and water can also intrude. On Maui, any efforts to underground lines would have to contend with rising sea levels that could eat at the soil supporting the pipes. “It all comes down to this overarching problem, that there is no place to locate power lines where there is zero threat of environmental interaction,” says Kury. “It's all about weighing relative risks: What are you most concerned with?”

Alternatively, there are ways to shore up aboveground electrical infrastructure to make it more resistant to failure and sparking. Utility poles can be made out of stronger composite materials or steel instead of wood, and secured to the ground with guy wires. (Singh says PG&E is reinforcing its aboveground infrastructure like this, in addition to its undergrounding efforts.) Clearing trees away from the infrastructure keeps branches from tearing down lines and removes the fuel that would allow a small fire to turn into a big, uncontrollable one. 

Some researchers, like Patricia Hidalgo-Gonzalez, director of the Renewable Energy and Advanced Mathematics Laboratory at UC San Diego, are investigating another way to provide communities with more reliable power and reduce the risk of wildfire: the microgrid. This is typically a system of solar panels that charge a large battery, which can be drained if the larger grid goes down, “islanding” the community. In the event that a regional utility does a public safety power shutoff, the microgrid can keep humming along. 

Hidalgo-Gonzalez is trying to figure out how to do this in disadvantaged communities, which may be at high fire risk because they lie in the wildland-urban interface, yet don’t have the funds to develop microgrids, which remain very expensive. “Would it make economic sense for the community to share the assets? Should it be like a co-op? Should this be subsidized?” asks Hidalgo-Gonzalez. “It will depend ultimately on the community.”

But even a safer, more resilient power grid would only solve one component of the growing wildfire crisis. In a world primed to burn, any tiny ignition can lead to catastrophe. “Accidents will always happen,” says Michael Gollner, who leads the Fire Research Lab at UC Berkeley. “A kid with matches, a chain dangling off a car, a weed whacker hitting a rock. If we removed all the power infrastructure ignitions, we'd still have fires on those high-wind days.” So there’s no substitute for better management of fuels: replacing invasive species with native ones and removing dead vegetation, especially around electrical infrastructure. 

“We're not talking about clear-cutting,” says Gollner. In forested areas, it’s about reducing the number of shrubs that fires use as a ladder to climb into trees, creating the kind of towering “crown fires” that hop from treetop to treetop. If the fire can’t make it into the treetops, “the fire is half as tall, and it's not spreading as fast,” he continues. “That makes a big difference. You now have a fire where it's safe enough for firefighters to operate. You give yourself that extra time for people to evacuate.”

For utilities in the ever-drier American West, burying lines is costly, but it is still less costly than the billions of dollars in damages unleashed by a single blaze, or the incalculable loss of human life. It’s not a panacea, but it’s a start. “I would say that the impact of not undergrounding, from a societal cost perspective, is far greater,” says Singh. “In these types of conditions it’s too expensive not to do it.”