In fire prevention test, PG&E installing underground lines along rural Sonoma County road

The $1.6 million test project on Bohemian Highway is intended to assess undergrounding power lines as a wildfire prevention strategy.|

By the numbers, PG&E and wildfire prevention

Cost of Bohemian Hwy. underground line (0.5 mile): $1.6 million

Estimated cost of undergrounding 7,000 miles of power lines throughout PG&E's high-risk fire areas: $20 billion

Potential PG&E liability for wildfire damage in past two years: $27 billion

Miles of underground power lines in PG&E territory: 26,000

PG&E is testing an expensive and admittedly imperfect strategy for curbing future wildfires by putting power lines underground along a half-mile stretch of a rural road near Monte Rio in western Sonoma County.

The underground pilot project, a first in the fire-scarred North Bay, got started in October on a narrow, tree-lined stretch of Bohemian Highway, deep within one of the county’s highest-risk wildfire areas. The job is scheduled for completion next month, when PG&E crews are scheduled to pull wire through plastic conduit already in place about 3 feet below the roadway.

The test project, following a similar pilot completed last month in the East Bay, is intended to “better understand the costs” and assess how putting power lines underground might fit into PG&E’s 10-year effort to “harden” 7,000 miles of power lines in high-risk areas across the utility giant’s 70,000-square-mile territory, said Paul Doherty, a company spokesman.

Budgeted at $1.6 million, the Sonoma County project tracks with PG&E’s estimate that burying lines costs about $3 million per mile, well beyond the $800,000 cost per mile to build overhead lines.

The California Public Utilities Commission, which regulates electric companies, puts the cost of the project at ?$1 million to $10 million per mile. With about 80,000 miles of power lines connecting homes and communities in wildfire hazard areas statewide, “it would take decades and cost ratepayers billions to underground throughout the state,” said Terrie Prosper, a PUC spokeswoman.

Using PG&E’s figures, burying lines throughout its own

highest risk areas would cost about $20 billion.

That’s a huge figure, but smaller than PG&E’s estimated $27 billion in potential liability for the wildfires of the past two years, including the October 2017 fires in Northern California, according to the state Department of Insurance.

PG&E’s precarious financial position is prompting pressure from shareholders, the financial industry, fire victims and their attorneys, with demands for compensation balanced against reluctance to drive the utility into bankruptcy on the grounds it would ultimately harm ratepayers.

California lawmakers will revisit the situation next year as the state braces for a future of catastrophic wildfires claiming homes and lives in what Gov. Jerry Brown has called the “new abnormal” -­ warming climate, combustible woodlands and millions of people living in harm’s way.

PG&E gained a measure of relief from a law signed in September allowing it to tap ratepayers for some of the costs of the 2017 fires, but no such protection exists for this year and state law holds utilities responsible for the cost of any fires started by their equipment - a doctrine PG&E has said it will challenge again next year.

The utilities commission last month gave PG&E and five other power companies until February to submit detailed plans to “prevent, combat and respond” to wildfires in their service areas. The so-called mitigation plans must outline strategies to “minimize the risk of electrical lines and equipment causing catastrophic wildfires.”

Cal Fire has determined PG&E equipment sparked at least 17 of last year’s major wildfires, along with evidence the utility was in violation of state safety laws in 11 cases. The agency’s report on the Tubbs fire is pending and there is speculation as well that PG&E equipment may have sparked the deadly Camp fire this month in Butte County.

Putting wires underground in high-risk areas could be included in PG&E’s mitigation plan, Doherty said. The utility already has launched a program to strengthen the 7,000 miles of power lines in areas of “extreme risk,” identified by the PUC.

Hardening the distribution system will include replacing wooden power poles with stronger, more weather-resistant poles, installing insulated wire and replacing transformers and fuses.

“The upgrades will be tailored to match terrain and conditions” in the high-risk areas, Doherty said.

The role of undergrounding has yet to be determined, and despite some calls to “put it underground” the strategy is “not a panacea,” he said.

Underground lines are susceptible to weather damage and vulnerable to floods, earthquakes, and lightning strikes as well as excavation damage by a third party. When damaged, underground lines can take twice as long to repair as overhead wires, Doherty said.

Michael Wara, a lawyer and Stanford University scholar focused on climate and energy policy, said putting lines underground is appealing because it eliminates the need to trim trees and brush along power lines.

But the high cost and risk of earthquake damage in seismically active places like the Bay Area are both drawbacks, he said. PG&E, in its current financial straits, will likely have trouble raising capital for any major system investment, Wara said.

The utility’s predicament, he said, is secondary to finding the most cost-effective way to combat California’s streak of catastrophic wildfires.

“We need to not have this happen again,” Wara said.

PG&E is no stranger to underground lines, with a distribution system that includes about ?26,000 miles of underground lines and 81,000 miles of overhead lines serving 5.4 million customers from Bakersfield to Eureka.

Each year, the utility puts about 30 miles of overhead lines underground through a program authorized by the utilities commission. Cities and counties, developers and individual property owners may apply for conversions - done primarily for aesthetics in urban and suburban areas - with the costs apportioned in different ways between PG&E ratepayers and landowners.

Since 2012, more than $300 million has been spent on burying power lines under the so-called Rule 20 Program.

In the fire-impacted Santa Rosa area, there were 80 miles of underground lines, PG&E said.

Brad Sherwood, who lost his home in the fire-ravaged Larkfield Estates neighborhood, said residents were dismayed to see PG&E rebuild the pre-existing network of overhead lines in older areas of the subdivision. Newer areas are served by underground lines.

Sherwood said he understands PG&E was bound to a “like for like” rebuilding policy, and the Larkfield residents are now seeking a conversion initiated by the county.

“We’re trying to build a community that’s safer and more resilient,” Sherwood said.

You can reach Staff Writer Guy Kovner at 707-521-5457 or On Twitter @guykovner.

By the numbers, PG&E and wildfire prevention

Cost of Bohemian Hwy. underground line (0.5 mile): $1.6 million

Estimated cost of undergrounding 7,000 miles of power lines throughout PG&E's high-risk fire areas: $20 billion

Potential PG&E liability for wildfire damage in past two years: $27 billion

Miles of underground power lines in PG&E territory: 26,000

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