PG&E POWER LINE FAILURE MIGHT HAVE SPARKED FIRE
Kincade: Utility opted not to shut down line; Cal Fire investigates
Once again, PG&E’s electrical equipment is under suspicion as the possible cause of a devastating wildfire, even after the embattled utility subjected homes and businesses to widespread blackouts to keep its lines from sparking another inferno amid high winds.
Questions are swirling after PG&E disclosed to state regulators that a transmission line, which it had decided not to turn off, malfunctioned as wind gusts over 40 mph buffeted the oaks and dry grasses covering the hills north of the Sonoma County town of Geyserville.
“It’s troubling beyond belief,” said state Sen. Jerry Hill, D-San Mateo, whose district includes a neighborhood where a 2010 PG&E gas pipe explosion killed eight peo
ple and led to criminal convictions for the utility over safety violations. “You see this accumulation of failures.”
Cal Fire, the California Department of Forestry and Fire Protection, continues to investigate the cause of the Kincade Fire. Pacific Gas and Electric would only say Friday that it is continuing to investigate what happened to the 43-year-old transmission tower and that its disclosure Thursday was preliminary. Company officials declined to answer further questions.
The Kincade Fire erupted during fierce winds about 9:24 p.m. Wednesday near The Geysers, the world’s largest complex of geothermal plants where steam from deep in the ground has been tapped for nearly a century to produce electricity.
PG&E said in its filing with regulators that at 9:20 p.m. Wednesday, a 230,000volt transmission line in that area suffered an “outage” when safety equipment tripped like a household circuit breaker.
Firefighters roped off the area around the transmission tower and showed a utility line inspector who arrived at the site the next morning “what appeared to be a broken jumper” on it. A jumper is a line that connects transmission wire segments around the insulated connection points to the towers. PG&E indicated that a jumper also was involved in the failure that ignited the Camp Fire.
Such a failure could certainly have produced significant arcing or sparks that might have ignited a fire, said James Orosz, an electrical engineer with the investigation firm Robson Forensic who formerly worked for Con Edison.
“If that were to become
broken or disconnected, it could cause an arcing condition,” Orosz said, a situation where electric current moves through the air like a static spark from shuffling across a carpet and reaching for a metal door knob. With a 230,000-volt line, however, that spark is “thousands of degrees.”
“It will melt metal and cause a tremendous amount of light and heat,” Orosz said. “And that’s where the concern comes in with these fires, this molten metal falling onto dry ground where there’s combustible material.”
PG&E said it had inspected the tower in question earlier this year as part of its Wildfire Safety Inspection Program.
But the utility also decided to leave the transmission line energized even as it turned off others to avoid wildfire risk, raising further questions. PG&E said “forecast weather conditions, particularly wind speeds, did
not trigger” a need for shutting off transmission lines.
“The wind speeds of concern for transmission lines are higher than those for distribution” lines, PG&E said.
But PG&E would not answer questions Friday about what its standards are for the different types of lines. Neither would the California Public Utilities Commission, which referred questions to PG&E.
PG&E equipment has been blamed for sparking a host of recent devastating wildfires, including many deadly blazes that roared through the Wine Country in 2017, as well as the Camp Fire that destroyed the town of Paradise east of Chico last year, the state’s deadliest and most destructive.
Facing multibillion-dollar liability claims, PG&E in January filed for bankruptcy protection. PG&E began initiating “public safety power shutoffs” last year, something San Diego Gas and Electric has used effectively
to reduce wildfire danger since the deadly 2007 Witch Fire. PG&E was criticized for its decision not to deenergize high-voltage lines near Paradise during strong fall winds that sparked the Camp Fire.
PG&E was under pressure to limit outages this week after cutting power to some 735,000 homes and businesses during strong, dry winds earlier this month. Gov. Gavin Newsom and others criticized the utility for what they called needlessly widespread blackouts. Transmission lines like the one PG&E said suffered the outage Wednesday are major arteries delivering power across the state.
But Calpine, a Houston energy company that runs
many of the geothermal plants at The Geysers where the fire originated, said it shut down its own power lines out of concern about the wind.
“Due to the wind conditions we had de-energized our local power line system before the fire started,” Calpine spokesman Brett Kerr said. Though the Kincade Fire “flashed through a portion of our Geysers geothermal facilities” Wednesday, Kerr said “we do not believe our facilities caused the fire” and noted that “there are power lines operated by third parties across The Geysers.”
A 230,000-volt line is a midlevel transmission line, designed to carry high voltage over long distances,
Orosz said. Distribution lines then carry tens of thousands of volts from those transmission lines into neighborhoods.
According to the National Weather Service, the Geyserville area had sustained winds of 21 mph around 9:30 p.m. Wednesday with gusts up to 42 mph. Winds peaked at midnight, with sustained winds of 52 mph and gusts up to 76 mph. Sustained winds of 39-54 mph are considered gale force, while a hurricane has sustained winds over 74 mph.
The Camp Fire began when a PG&E transmission tower east of Paradise failed as winds gusted to 50 mph the morning of Nov. 8, 2018. A suspension insulator supporting a transposition jumper separated from an arm on a tower carrying 115,000-volt transmission lines, causing a flash that showered sparks on dry brush below.
Newsom has blamed PG&E for both the forced blackouts and fires, arguing Friday that “years and years of greed, years and years of mismanagement” left its electrical power system in poor shape and unable to effectively limit wildfire damage.
Hill said he hopes the federal judges overseeing PG&E’s probation for the San Bruno explosion and the bankruptcy proceeding force a management takeover.
“I think this calls for drastic action and quick action,” Hill said. “I think for the protection of California and its residents, one should replace its current ineffective and irresponsible management. “It is just beyond belief that this company is as bad as it’s been and continues to be.”