Do California power shutoffs work? Hard to know, experts say - California Homeowners AssociationCalifornia Homeowners Association

SAN FRANCISCO (AP) — Millions of Californians spent part of the week in the dark in an unprecedented effort by the state’s large electrical utilities to prevent another devastating wildfire. It was the fifth time Pacific Gas & Electric Co. has preemptively cut the power but by far the largest to date in the utility’s effort to prevent a deadly wildfire sparked by its power lines.

But do the power shut-offs actually prevent fires?

Experts say it’s hard to know what might have happened had the power stayed on, or if the utility’s proactive shutoffs are to thank for California’s mild fire season this year.

“It’s like trying to prove a negative,” said Alan Scheller-Wolf, professor of operations management and an energy expert at Carnegie Mellon’s Tepper School of Business. “They can’t prove they prevented a disaster because there’s no alternative universe where they didn’t try this.”

The winds that prompted the mass outage that affected about 2 million people in northern and central parts of the state shifted southward by Thursday, where a wind-driven wildfire led officials to order the evacuation of 100,000 people from their homes in foothills of the San Fernando Valley.