The blackout affected about 130,000 residents in the California city of around 800,000 people, PG&E said.

“Crews restored about 110,000 customers by 7.30am Sunday and are working to restore the power for around 21,000 who remain without electric service,” the utility said, adding that there were no injuries to workers or members of the public.

The energy provider expects to restore all remaining impacted customers by no later than 2pm PT (2200 GMT), it added in an update.

The outage caused traffic jams and forced some businesses to close temporarily.

“A large power outage is impacting San Francisco – only call 9-1-1 for life safety emergencies, avoid non-essential travel, treat down traffic signals as four-way stops, keep refrigerator and freezer doors closed, and turn off major appliances to prevent surges,” the San Francisco department of emergency management said in a post on social media earlier on Sunday.

Separately, Tesla CEO Elon Musk said on Sunday the company’s robotaxis were unaffected by the outage.