Pacific Gas and Electric Co. said it is investigating whether or not a piece of its equipment was involved in igniting an October 24 wildfire in Sonoma County, California.

The California Department of Forestry and Fire Protection (Cal Fire) said that roughly 24 hours after the fire began it had burned 16,000 acres of vegetation and destroyed 49 structures.

The utility said it filed an electric incident report with the California Public Utilities Commission related to the blaze, which is known as the Kincade Fire.

In the report, PG&E said that on October 23 it had begun a Public Safety Power Shutoff (PSPS) to switch off the power to nearly 28,000 customers in Sonoma County. As part of that action, PG&E distribution lines in the area were de-energized. However, following what it said were established protocols and procedures, PG&E allowed transmission lines in the area to remain energized.

Earlier in October, PG&E shut off power to more than 700,000 customers due to high winds which raised fears about wildfire. That shutoff and subsequent line inspection left some customers without power for days, and led to a heated response from the state's chief utility regulator.

"Failures in execution"

“Failures in execution, combined with the magnitude of this event, created an unacceptable situation that should never be repeated,” said CPUC president Marybel Batjer. “The scope, scale, complexity, and overall impact to people’s lives, businesses, and the economy of this action cannot be understated,” she said in a statement.

Some of the corrective actions outlined in a letter from Batjer to PG&E CEO William Johnson included accelerating power restoration with a goal of less than 12 hours; enhancing efforts to minimize the size and magnitude of future PSPS events; developing systems and protocols to ensure public information through call centers and PG&E’s website; establishing a more effective communication structure with county and tribal government emergency management personnel; improving processes and systems for distributing maps that match the latest PSPS impact information; and, ensuring that PG&E personnel involved in PSPS response in Emergency Operations Centers are trained in California’s Standardized Emergency Management System.

Pull the trigger?

The utility said that transmission lines near the Kincade fire were not de-energized because forecast weather conditions, particularly wind speeds, did not trigger its PSPS protocol. Wind speeds of concern for transmission lines are higher than those for distribution lines, the utility said.

PG&E told regulators that it became aware of a transmission level outage on what it referred to as the Geysers #9 Lakeville 230kV line when the line relayed and did not reclose, de-energizing the line. That incident occurred at around 9:20 pm on October 23.

In 24 hours the Kincaide fire had burned 49 structures. Source: NPR/Josh Edelson/AFP via Getty ImagesThe next morning, at around 7:30 a.m., a PG&E worker patrolling the line saw that Cal Fire had taped off the area around the base of transmission tower 001/006 in the area of the Kincade Fire. Fire crews pointed to what appeared to be a broken jumper on the tower.

The utility said that particular transmission tower was inspected earlier this year as part of PG&E's Wildfire Safety Inspection Program.

Trouble with the grid?

The utility has acknowledged that its equipment played a role in the 2018 Camp Fire, which burned a total of 153,336 acres, destroyed 18,804 structures and resulted in 85 civilian fatalities and several firefighter injuries. Faced with potential liabilities of as much as $30 billion from that and earlier fires, PG&E filed for bankruptcy protection earlier in 2019.

(Read "Insight: The wind blows and the electric grid creaks.")

The disaster also prompted the utility to adopt a policy of proactively shutting off power in areas where high winds and dry vegetation could combine to spark wildfires if energized utility equipment fails or comes into contact with dry fuel.

In late September, PG&E cut off power to around 48,000 customers as weather conditions deteriorated to the point that shutdown protocols were triggered. It cut power again in early October, this time affecting fewer than 11,000 customers. An even larger disruption was announced on October 8 when the utility said that it would implement a public safety power shutoff (PSPS) in portions of 34 northern, central and coastal counties, affecting nearly 800,000 customers or around 2.1 million people.

In that incident, the utility warned that power could be off for days, first as the weather event blew through and then as crews inspected and, if needed, repaired damaged power lines and equipment.

State action

In early October, California governer Gavin Newsom signed into law a package of bills intended to help the state forecast major wildfires, oversee tree clearing around power lines and enhance community disaster preparation.

The 22 new laws are part of an effort to help the state prepare for and prevent climate-driven wildfires. For example, Senate Bill 209 establishes a wildfire warning center intended to enhance the state’s ability to predict and prepare for wildfires using a statewide network of automated weather stations and fire detection cameras. The state-run center will be led by the Office of Emergency Services and Cal Fire and have access to public warning systems.