Utilities would be required to turn off or “de-energize” powerlines during extreme weather conditions, under legislation introduced by a state senator from Napa.

Wildfires in early October devastated large areas of Sonoma, Napa and Mendocino counties, and parts of Lake and Solano counties, destroying thousands of homes. Fires began and spread rapidly with high winds and hot temperatures.

No causes have been determined, but investigators have been looking into damaged Pacific Gas & Electric Co. equipment near possible ignition points of the fires. Lawsuits have already been filed alleging downed powerlines could be to blame.

State Sen. Bill Dodd on Wednesday announced legislation, Senate Bill 901, that he said would require utilities to include plans to de-energize powerlines as part of required plans to deal with wildfires.

“This last fire season underscored the need to think innovatively and proactively about fire prevention,” said Dodd in a statement. “We know downed power lines have caused devastating fires in the past, and we need electric utilities and the Public Utilities Commission to plan ahead and implement best practices. This isn’t a panacea, but it’s an important part of the holistic improvements needed for fire prevention and preparedness.”

Dodd pointed out that Southern California-based SDG&E has “developed a set of policies and procedures to determine if, when and where it may need to temporarily de-energize a power line to prevent the possibility of triggering a wildfire, and has done so at least 17 times.”

Napa County Supervisor Diane Dillon, who represents portions of the county hit by the Tubbs fire, which was the most destructive fire in state history, said the bill addresses "what we can do proactively when circumstances, like the speed of wind or other natural factors, are beyond our control.”

“Although the causes of these unprecedented wildfires remain under investigation, this experience highlights a need to think differently about our approach to emergency preparedness statewide,” she said.

SB 901 is co-authored by Sen. Mike McGuire, D-Healdsburg, and Assemblymembers Jim Wood, D-Healdsburg, and Marc Levine, D-San Rafael. It is expected to get its first committee hearing in March.