Pacific Gas & Electric, aiming to show its determination to overcome a history of safety problems, announced Wednesday that it planned to put 10,000 miles of its power lines underground to prevent the kind of wildfires that led the utility to bankruptcy court.
The project, which would involve about 10 percent of the lines currently above ground, could cost tens of billions of dollars to carry out. The announcement prompted questions from longtime critics of the utility about how much of the cost would be borne by ratepayers rather than shareholders.
The company, California’s largest electricity provider, said the work would aim first at areas most vulnerable to wildfires and expand throughout its service territory, which includes 5.5 million electric customers in Northern and Central California.
PG&E’s announcement came days after a preliminary report to state regulators said that its equipment might have caused the Dixie Fire, one of the state’s largest blazes, which has burned at least 85,000 acres. The fire is spreading in Butte County, where the utility’s equipment caused a fire that destroyed the town of Paradise and killed 85 people in 2018.
Although utilities across the country have increasingly moved their power lines underground, none have proposed a project on the scale of PG&E’s plan. Currently, the utility has 27,000 miles of power lines underground, but they are generally not in areas at high risk of wildfires.
“We need you to know that we are working night and day to solve this incredible problem,” said Patricia K. Poppe, chief executive of PG&E Corporation, the utility’s parent.
This year the company is putting 70 miles of lines underground, so increasing the work to 1,000 miles a year would be a leap. “That’s the moonshot,” Ms. Poppe said on a call with reporters. “It should be a shocking number because it’s a big goal.”
By comparison, President Biden’s infrastructure proposal calls for $73 billion to improve the nation’s power grid. Though the spending is meant to counter the effects of climate change, the prospect of more transmission lines has led to calls for greater reliance instead on rooftop solar panels and battery storage.
Ms. Poppe, who previously held positions at General Motors and two power providers, became PG&E’s chief executive on Jan. 1 as part of its overhaul after the company emerged from bankruptcy. She said that the company had planned to make the announcement on underground power lines in a few months but that it had decided to do so now because of the growing public concern about fire safety.
Mark Toney, executive director of the Utility Reform Network, which represents consumers before the California Public Utilities Commission and has often been a PG&E adversary, said that reducing wildfire risk was a priority but that the utility must develop a plan that would fund the huge project without overburdening ratepayers. Based on underground power line proposals that PG&E has previously submitted to state regulators, the project could cost about $4 million per mile, or $40 billion overall, Mr. Toney said.
“We’d be living in a world where only the wealthy could afford electricity,” he said. “PG&E needs a plan to reduce the most risk possible at the least cost possible to ratepayers.”
Mayor Sam Liccardo of San Jose also questioned the ability to finance such an ambitious undertaking without burdening consumers. “If we assume that all of PG&E’s ratepayers win the lottery at the same time, PG&E’s right, we can do this,” said Mr. Liccardo, who sought unsuccessfully during PG&E’s bankruptcy to turn the utility into a cooperative rather than a publicly held company.
The Public Utilities Commission said it would consider PG&E’s project when the utility formally submits it for review, a process that would include public hearings.
Ms. Poppe said the utility hoped to get the per-mile expense down sufficiently to put the overall cost at $15 billion to $20 billion. “We can’t put a price on the risk reduction and safety,” she said. But she did not directly address the financing.
About 18 percent of the country’s electric distribution lines are buried, including those for nearly all new residential and commercial developments, according to the Edison Electric Institute, an industry trade group.
PG&E has been a focus of the impact of climate change since a series of record-setting wildfires began burning through Northern California in 2017, several of them caused by the utility’s equipment.
The utility has taken several steps to prevent fires, including installing equipment to monitor weather conditions and to allow lines to be shut off remotely. It has sent crews to cut back tree branches and clear other vegetation that could come in contact with power lines, a concern that has grown along with California’s widespread drought conditions.
But the effectiveness of those efforts has increasingly come under question, particularly after the company reported that its equipment might have caused the Dixie Fire. The wildfire season has months to go before its peak.
State regulators and the courts have fined the utility billions of dollars for failing to maintain its equipment and causing fires. The company, which filed for bankruptcy protection in 2019 after amassing $30 billion in wildfire liability, pleaded guilty last year to 84 counts of involuntary manslaughter related to the Paradise fire.
It was the second felony conviction for the utility. In 2016, PG&E was found guilty of federal charges related to a gas pipeline explosion six years earlier in the San Francisco suburb of San Bruno that killed eight people. That episode led the Public Utilities Commission to conclude that the company was more concerned with profit than with safety.
In recent years, PG&E has also angered millions of customers by cutting their power to prevent its equipment from igniting fires during severe weather. Some were without electricity for as long as a week.
Sheelagh McNeill contributed research.