Is Burying Power Lines Fire-Prevention Magic, or Magical Thinking?

With the West stricken by rising temperatures, deepening drought and blasting winds, often all that’s needed to ignite a fire is a spark. Increasingly, power lines strung through expansive wildlands to sprawling Western communities provide the flashes that grow into megafires.

Burying electrical distribution lines prevents nearly all such ignitions, and the related power outages, but prices of up to $4 million or more for each mile of “undergrounding,” and difficult logistics have prevented widespread adoption of the practice.

Power lines shouldn’t be sparking wildfires anymore, said Paul Chinowsky of Resilient Analytics, an engineering consulting firm in Boulder, Colorado that focuses on adaptation to climate impacts. 

“This should be one of the top priorities that’s going on in the West,” Chinowosky said. “If we want to minimize wildfires, if we want to minimize the risk to our reliability, start undergrounding.” 

Chinowsky almost lost his house in the Marshall Fire, which burned the most homes in Colorado history when it ignited in December 2021. The blaze, for which a power line is still considered a possible culprit, reached his porch and burned down his neighbors’ houses. Four months afterwards, he still wasn’t living back at home.

While it’s possible to make structures more resilient to wildfires with everything from fire resistant building materials to sprinkler systems, their effectiveness plummets when 100 mph winds blast conflagrations through neighborhoods. That makes preventing ignitions a priority, Chinowski said.

“You’ve got to minimize the threat from the power source because you can only do so much minimizing it to the structures,” he said. “And right now, the most effective way to minimize that is to underground.”

Across the U.S., wildfires are increasing both in frequency and intensity, a trend expected to accelerate with climate change. Core fire seasons are on average 78 days longer than they were in the 1970s, according to the Colorado Division of Fire Prevention and Control’s 2022 Wildfire Preparedness Plan. This can push the wildfire season into historically windy times, often to catastrophic effect, Colorado State Climatologist Russ Schumacher recently told the state Public Utilities Commission. And destructive blazes aren’t isolated to rural wildlands, but are also burning in suburban grasslands, as with the Marshall Fire. As development sprawls into flammable landscapes, humans become their primary fire starters, including from the widening web of power lines.

That’s increasingly forced utility executives to choose between cutting off customers from electricity during days or weeks of extreme fire weather, or risking igniting deadly fires with their power lines, which are often overtaxed by air conditioning during heat waves. 

While burying power lines can almost eliminate their potential to start fires, it’s an expensive solution, with costs of millions of dollars a mile that are passed on to consumers. That makes the solution a hard pill to swallow for utility companies, residents and public utility commissions. And undergrounding can be slow, with utility corridors crossing various jurisdictions, including public lands where federal reviews can delay and even stymie projects.

A Heated Debate Over a Growing Threat

The debate over burying power lines is going on across the country as extreme weather batters above-ground electricity transmission equipment, and rapidly expanding populations overtax the capacity of aging infrastructure. According to the National Interagency Fire Center, from 1992 to 2020 federal, state and local fire services dealt with 32,652 powerline-ignited wildfires across the country. Without mitigation of power lines’ potential to start fires, those numbers are sure to grow, as fighting climate change has sparked a movement to “electrifying everything,” which requires a rapid expansion of power distribution networks.

The argument is most heated in California, where a nearly 100-year-old power line in a drought-stricken, overgrown forest sparked 2018’s Camp Fire, the state’s deadliest and most destructive wildfire, which killed 85 people and destroyed nearly 19,000 structures. Utility-ignited wildfires have made headlines in the state for years. In 2007, the Guejito, Witch and Rice fires scorched 207,000 acres, destroyed 1,141 homes and killed two people in San Diego County. Investigators determined that San Diego Gas & Electric power lines and Cox Communications cables ignited the fires in vegetation that hadn’t been properly cleared around them—maintenance that utilities are required to do, but are often years behind schedule in completing.

Such disasters pose their own costs to utilities and consumers. Southern California Edison paid out more than a half a billion dollars in fines and penalties in a settlement with California’s Public Utilities Commission over its role in five wildfires in 2017 and 2018. And dozens of deadly and destructive wildfires started by Pacific Gas and Electric (PG&E) equipment in recent years led to lawsuits and penalties that forced the utility to file for bankruptcy.

“PG&E is a poster child for a lot of things that can go wrong, if you don’t spend your money on maintenance and take care of things the way you should,” said Mark McGranaghan, a fellow at the Electric Power Research Institute who specializes in grid modernization. “But you can do everything right and a fire can still start from the electrical system.”

In California alone, wildfires ignited by electric power accounted for 19 percent of the acreage burned from 2016-2020, according to Cal Fire. A recent California Auditor’s report cited power lines as the cause of six of the state’s 20 most destructive wildfires since 2015. As of June 2021, there were nearly 40,000 miles of exposed power lines in high fire-threat areas of the state, a hazard California utilities are approaching with renewed urgency.

“We live here too,” said Jamie Martin, PG&E’s vice president of undergrounding in California. “Our parents live here, our friends live here, our neighbors. We are part of the community, and we take it very seriously. It is our hometowns that we’re serving, and it is their safety that’s most important to all of us.”

A New Sense of Urgency for an Old Fix

San Diego Gas and Electric started undergrounding its circuits in the late 1960s, but it was a slow process, with, until recently, a goal to bury 15 miles a year in the City of San Diego. But in 2020, the company specifically included undergrounding as part of its Wildfire Mitigation Plan, increasing the amount of lines it buried from three miles in 2019 to 26 miles in 2021, with plans to bury more than 100 miles a year by 2023. 

New developments often bury all utilities, but most of the country’s existing electric infrastructure is above ground and outdated. 

Utilities typically rely on historical data to plan projects, rather than considering current or forecasted conditions that account for climate change. A recent Reuters investigation of more than 10,000 regulatory documents and public disclosures found that regional grid operators across the U.S. consistently use data from as far back as the 1970s in their risk modeling, which guides future transmission-network investments.

“None account for scientific research documenting today’s more extreme weather and how it can disrupt grid generation, transmission and fuel supplies simultaneously,” the reporting stated.

This leaves the entire country’s electric grid vulnerable to severe weather that can cause outages and, in areas with strong winds, high temperatures and abundant, dry vegetation, public safety power shut-offs to prevent wildfires.

“All of our infrastructure really is designed with an assumption that the future is going to be like the past,” Chinowsky, of Resilient Analytics, said. “But we’re finding, obviously, that’s not necessarily the case … most infrastructure is well past its design lifetime expectancy and with climate change, you’ve got an acceleration of that degradation.”

California’s PG&E is beginning to use wildfire risk modeling to look ahead, announcing a plan in 2021 to bury 10,000 miles of power lines and equipment in areas with high fire risk—the largest undergrounding effort in the country. The announcement came after the company’s equipment caused numerous large, deadly and destructive wildfires, liability lawsuits and bankruptcy, but state officials discouraged the use of public safety shut-offs during extreme fire weather. The California Auditor’s report states that PG&E has by far the most lines hung in high wildfire risk areas of the state, with 80 percent of the utility’s power lines in such areas currently bare.

PG&E’s modeling shows burying lines reduces their risk of igniting wildfires by approximately 99 percent, and the company’s undergrounding plan eliminates 70 percent to 80 percent of the ignition risk in high-fire districts, Martin, the Vice president of undergrounding, said. 

“Permanent wildfire risk reduction is the driver of this program,”  she said. “Undergrounding a line reduces the risk of ignition. It nearly eliminates it. ”

In 2021, the company buried 70 miles of line, Martin said. Testing different methods of construction and drilling allowed PG&E to efficiently scale up projects and it is currently on track to achieve its goal of undergrounding 175 miles of distribution lines in 2022, she said. The program plans to bury 400 miles in 2023 and increase that to 1,200 by 2026, with areas impacted by past wildfires among the prioritized areas.

“These are risk-informed miles,” Martin said. “We’ll build the portfolios to balance a whole host of things, community impacts, executability, the ability to deploy our resources and sequence the work thoughtfully.”

Risk-reduction methods on the infrastructure that remains above ground includes installing stronger poles, covering exposed power lines, cutting vegetation away from lines and, when necessary, shutting off power lines during extreme fire weather. It has installed more than 1,000 weather stations and hundreds of cameras to detect ignitions early.

“The whole concept of digitalization, sensors, communication, infrastructure, data analytics, artificial intelligence, all those areas have tremendous potential,” said McGranaghan, from the Electric Power Research Institute. Distributed generation from renewable energy sources like solar and wind, and microgrids built to serve small communities could help make the electrical system more resilient to climate threats, he added. “But undergrounding is a solution now. It’s there, ready to be implemented. So targeted undergrounding where the risks are greatest is kind of a no brainer.”

High Costs Spark Resistance

Still, not all utilities are undergrounding to reduce ignitions. Xcel, the Minneapolis-based utility that operates much of the power system in Colorado’s populous Front Range, where December’s Marshall Fire burned, has considered it, but doesn’t include it in its current wildfire prevention strategy. The cost to bury lines in the state’s rugged terrain can be 10 times higher than installing overhead lines, a company spokesperson said. That cost would be passed onto the customer, something that the company is skeptical that the state’s Public Utility Commission, charged with keeping rates affordable, would approve.

There are areas where Xcel is burying lines, working with the City of Boulder, for example, in areas with reliability issues, like the century-old Colorado Chautauqua, a city park and National Historic Landmark. Elsewhere, Xcel is pursuing more traditional strategies to reduce wildfire risk, such as increasing the frequency of equipment inspection, hardening the system with materials like fire-resistant steel and trimming trees near equipment that could ignite them.

The terrain across the Western United States is so varied that burying power lines will never be a wholesale solution across the region, many utility experts report. Mountain ranges and waterways create cost-prohibitive barriers to undergrounding in many existing utility corridors.  

“It’s not always doable in some areas based on the local geology. If it’s a really rocky area, if you’re near bedrock, it can be orders of magnitude more expensive to bury cables there,” said Joseph Lake, principal at the UMS Group Inc. and program director of the International Wildfire Risk Mitigation Consortium, a group of 18 utilities worldwide developing best practices to reduce fire hazards.

“A utility would gladly underground every mile of their line if they could pay for it,” he said. “There’s a resistance to appearing like you’re gold plating your system.”

Investing in a Fire-Safe Grid

Other mitigation efforts are exponentially cheaper. Coating bare lines is much easier, and provides a high degree of risk reduction, Lake said. Utilities have also increased their vegetation management, hiring arborists to identify trees at high risk of striking power lines (Although the industry acknowledges the historic failures of utilities to effectively manage woody fuels in their utility corridors). 

Public safety shut-offs are also a cost-effective solution—one more and more utilities are utilizing, said Joe Stutler, co-chair of the Western Region for the National Wildland Fire Cohesive Strategy.

Utility companies have “armed themselves with meteorologists that can predict the winds and are tracking fire danger. “And they simply say we’re just going to shut the power off,” Stutler said. “We’re just going to get the American public that uses the utilities to accept the fact that there may be a 24- or 48-hour period that we’re going to have power down and, you know, go to Walmart and buy a generator or light a candle.”

Buried lines are worth the price, Martin, from PG&E, said, particularly as it is usually paid out over time and cuts other costs associated with above-ground power lines, including for other mitigation strategies.

“The magic of undergrounding is that it’s a one-time investment for permanent risk reduction,” Martin said. Customers are “getting immediate risk reduction, but they pay for that project over decades. And at the same time, you reduce, and in some cases eliminate, ongoing operations and maintenance costs.”

PG&E is on track with its target cost of $3.75 million a mile for its current undergrounding projects, she said, and she expects that to drop to $2 million a mile in the coming years as the company gains experience and finds efficiencies. 

“One of our greatest lessons learned is that underground work can be done economically for customers, and I think that’s a big unlock, certainly for us internally at PG&E,” she said. “In certain cases it can be a big unlock for other utilities.” 

There also may be federal funding that could ease some of the financial burden to utilities and their customers eventually. 2021’s bipartisan infrastructure bill set aside $5 billion to prevent power outages and enhance the resilience of the country’s electric grid, and included undergrounding as one of the “eligible solutions.”

The process may be expensive up front, McGranaghan said, but there are cost savings to keeping the lights on during blazes and extreme fire weather. It’s one thing if residential power goes out for hours or days, but cutting electricity to hospitals, manufacturing plants and other businesses can be much costlier.

“Those are expensive,” McGranaghan said. “Those have big impacts on society and can justify some expenditures to prevent those events.”

Wildfires aren’t the only climate-fueled disasters driving undergrounding initiatives. In the wake of 2012’s Hurricane Sandy, New York has started burying power lines and updated grid requirements, as has Florida in response to its expanding hurricane season. Texas explored undergrounding after a February 2021 ice storm  shut down much of its electric grid for days.

In Alaska, there are entire communities that have buried power lines to ensure reliable electricity during the state’s variable and extreme weather.  

“The industry paradigm is that it’s more expensive to install underground, but that’s a short term and inexperienced view,” said Clay Koplin, CEO of Cordova Electric Cooperative in Alaska. 

“We had to learn some hard lessons,” he said. “We had to make some mistakes and do it wrong, once, hopefully, or twice or three times, and then get better at it as we went. You have these failure modes, you catalog them, you find ways to mitigate them and you do it better the next time. And pretty soon you find that the cost effective and safe and reliable approach.”

Although Cordova, in the coastal rainforest, sees few wildfires, it gets dozens of feet of snow, pummeling rainstorms, hurricane-force winds, avalanches, earthquakes, tsunamis and even volcanic activity that can fill the air with abrasive ash, threatening circuitry. Some flooding was so bad that buried electrical equipment was submerged for days, but it still worked. The first winter after the undergrounding of the entire system was completed in 2011, Koplin said Cordova saw 30 feet of snow in three months. Yet the lights never went out.

By collaborating with other utilities that deliver their services over lines, such as telephone and cable television companies, and those that already bury pipes, like sewer and water services, along with improving project designs and installation techniques, the Cordova Electric Cooperative made the cost of undergrounding competitive with stringing lines above ground, Koplin said.

“I would argue we installed most of our underground more inexpensively than you could have installed overhead and still gained all of the benefits—better life safety, better animal safety, better visual aesthetics, much, much higher reliability,” he said.

In 2007, the cooperative buried seven miles of cable through critical state wildlife refuge and U.S. Forest Service lands, crossing 11 waterways along the way, for $2.3 million, half of which was funded by the FAA because the lines served the airport.

“The industry paradigm is that it’s more expensive to install underground, but that’s a short term and inexperienced view,” he said. “If you recognize that there are solutions out there and you focus on what you want the outcomes to be, and then worry about the ways to get there, then there are ways to do this.”

Others disagree. Utility corridors that go through public lands make undergrounding time consuming and cost prohibitive, Stutler, from the National Wildfire Cohesive Strategy, said. Although utilities have rights of way through these habitats, the ground disturbance to bury power lines could trigger additional federal processes through the National Environmental Policy Act and the Antiquities Act. Tunneling beneath waterways to bury lines can significantly increase the cost and time required for a project, which are considered not only by the utilities, but the land management agencies. Either may determine that it’s more efficient to simply cut the power during extreme weather.

While it may make sense to bury lines in more urban and developed areas bordering wildlands, undergrounding in much of the expansive, undeveloped West where electrical lines start fires still faces significant challenges. Reactions to the recent increases in energy indicate consumers may resist footing the bill to bury power lines, even if it saves lives and homes. 

“How we fund these types of mitigations as a society and make those decisions as a society is really tough,” Lake, from the International Wildfire Risk Mitigation Consortium, said. “It all ties back to the cost, really, at the end of the day.”