Planned power shut-offs could increase in number and size under new criteria that PG&E is using to assess wildfire risk tied to its equipment.
That was the message Tuesday from PG&E and Sonoma County emergency officials to the Board of Supervisors, as the utility takes steps to more closely factor in trees that could pose a threat to power lines during severe weather, including the hot, windy conditions that can fuel catastrophic fires in the region.
The so-called “overstrike trees” are considered a risk to lines due to their height, density and health, among other factors.
Pacific Gas & Electric Co. estimates 5.3 million of those trees exist outside of its right of way in its Northern and Central California service area.
The new criteria mean Sonoma County’s average potential number of planned outages could increase from 2.1 to 3.8 annually, according to PG&E and county officials.
The average scope of those outages could also increase from 5,804 affected customers to 6,266.
The shut-offs are expected to max out in Sonoma County at about 23,000 customers, far smaller than the widespread Northern California outages of 2019 that resulted in a cascade of impacts on residents and businesses and $106 million in fines for PG&E.
“Looking back historically, the largest event in Sonoma County was the October weather event in 2019,” Aaron Johnson, PG&E’s vice president of the Bay Area region, told the board, referring to the period around the Kincade fire.
The utility shut off power to as many as 260,000 people across the county at the time — but opted not to cut de-energize high-voltage transmission lines in the area where Kincade fire began, sparked by a PG&E line high up in the Mayacamas Mountains. That decision is now part of a criminal case against utility brought by Sonoma County District Attorney Jill Ravitch.
PG&E, which emerged from its 17-month bankruptcy a year ago, has been touting for several years its efforts to adjust planned outages to be smaller in scope and number and shorter in duration.
Johnson said those efforts will continue under the new criteria.
“It really just adds smaller events,” he told the board.
PG&E has been using planned outages in the region since 2018 as a wildfire mitigation tool, turning off electricity when fire danger is highest, amid a combination of strong winds, low humidity and dry vegetation.
Many fire-prone areas of Sonoma County have experienced the outages, but PG&E has indicated new areas of west county could be affected under the new criteria.
The outages will not be new for most people countywide, said Jeff DuVal, deputy director for the county’s Department of Emergency Management.
“This county has already been through a lot,” DuVal said. “They’re very resilient and very Sonoma Ready. This wouldn’t be the first time that they would be affected like this.”
The new criteria come in the wake of rulings by a federal court judge and increased by California regulators over PG&E’s tree trimming activities and line maintenance. The utility’s equipment has been tied to a series of destructive and deadly fires, including several in the 2017 North Bay firestorm, the 2018 Camp fire in Butte County and the 2019 Kincade fire.
Just this week, the utility signaled that its equipment could be linked to the start of the Dixie fire burning in Butte and Plumas counties.
County emergency officials are briefing local governments, school boards, water suppliers and others likely to be affected by planned power outages, DuVal said.
Those weekly updates become daily briefings during large outages, fires, earthquakes and other disasters.
Supervisors’ big question to PG&E on Tuesday focused on its long-term plan to reduce the need for planned outages.
“We don’t want fires to happen but we really don’t want power shutdowns to happen. That’s really the goal,” said Supervisor Susan Gorin.
Gorin noted many residents, including those in Oakmont in her district, are installing solar panels and battery backup systems in a bid to create a microgrid that would insulate them from outages.
PG&E has begun work to put its power equipment underground, where possible, Johnson said. Several weeks ago, crews dug up roadway in Rincon Valley to bury 3.4 miles of overhead transmission lines along Calistoga Road.
“I hear the feedback loud and clear, more undergrounding and I think that’s something that we’re going to do,” Johnson said.
The utility’s line hardening work is part of a larger need to fundamentally “rebuild and redesign” its infrastructure, Johnson said.
The upgrades are costly, at roughly $2.3 million to convert underground electric distribution lines from overhead poles, according to PG&E. And customers can expect to see the expense passed on at least partly through higher bills.
That pairing — higher bills and the likelihood of more planned outages — is a source of frustration for many customers, said Supervisor…