The Los Angeles Fire Department is investigating a transmission tower owned and operated by Southern California Edison as the possible source of ignition of last week's Saddleridge Fire, LAFD Fire Captain Erik Scott told California Energy Markets. The fire was 68 percent contained as of Oct. 18, but gusty winds forecast this weekend are expected to test those containment lines, firefighter crews said.
LAFD investigators determined that the fire started on a hillside below SCE's 220-kV Gould-Sylmar transmission line in the San Fernando Valley. The fire has burned down or damaged at least 100 structures and is connected to two deaths so far.
"Preliminary information reflects SCE facilities were impacted close in time to the reported time of the fire," SCE Senior Manager Paul Pimentel wrote in an Oct. 11 report to the California Public Utilities Commission. "SCE submits this report out of an abundance of caution."
Electric utilities must report incidents to the CPUC in the following cases: a fatality or injury involving electric facilities; damage to property of the utility or others in excess of $50,000; significant media coverage; or a major outage to at least 10 percent of a utility's entire service territory at a single point in time.
Along with LAFD's fire investigators, SCE investigators are also on-site and examining the fire's origin location, which is a 50-foot-by-70-foot area below the transmission tower.
Investigators "continue to work around the clock in steep terrain," the LAFD said in a press release. However, they do not expect to issue a final report anytime soon, according to Scott, who cited the Thomas Fire investigation in Ventura County in 2017, which took about 11 months to complete. Scott said his team will be "slow, methodical and accurate."
In SCE's most recent risk-assessment report filed in November 2018, the utility did not address wildfire risks associated with its electric transmission assets, according to a report in May from the CPUC's Safety and Enforcement Division. The commission recommended that SCE treat both its distribution and transmission equipment equally, classifying them as Tier 1 wildfire risks and therefore as posing the greatest threat.
"The SCE [wildfire risk] report only addresses wildfire risks associated with its distribution assets," the CPUC said in its report. "It is known that transmission assets have been responsible for major wildfires and [therefore] should be addressed in utility capital projects."
"The safety impact of the risk associated with [transmission] assets did not rise to the level of inclusion as a top safety risk within our risk report," SCE's risk-assessment report said.
However, SCE is developing a plan to identify transmission line structures that pose the greatest risk of failure and evaluating mitigation options to address those structures, such as applying a coating to prevent further corrosion, according to the utility. SCE did not comment on whether the transmission tower under investigation in the Saddleridge fire had been identified as high-risk in its plan.
SCE's 2019 wildfire risk mitigation plan allocated about $103 million in capital costs for distribution-line overhead inspections and remediation in high-fire-risk areas, and about $10 million for transmission lines.
Transmission assets can be more costly and time-consuming to replace than distribution assets, according to SCE's 2021 general rate case, which cited a previous transmission pole replacement project along a major freeway that took years to complete.
For further context, last year near the town of Paradise, a hook on a transmission tower owned by Pacific Gas & Electric failed and started the Camp Fire, which killed 85 people.
SCE said it is continuing to monitor the Saddleridge fire as the investigation continues.