Summary (tl;dr)

A major power outage in San Francisco on December 20, 2025, caused by a fire at a PG&E substation, left approximately 130,000 customers without electricity, severely disrupted public transportation, and notably stranded numerous Waymo self-driving vehicles across the city.

Essential Background

San Francisco, a major metropolitan area in California, relies on Pacific Gas and Electric (PG&E) for its electrical power infrastructure. The city also hosts advanced technological services, including Waymo's autonomous ride-hailing system, which integrates with urban infrastructure like traffic signals for its operations.

The Full Story

On Saturday, December 20, 2025, a widespread power outage plunged approximately one-third of San Francisco, affecting around 130,000 PG&E customers, into darkness amidst rainy holiday season weather. The blackout was significantly influenced by a fire that erupted at a PG&E substation located at 8th and Mission Streets. This extensive power loss led to considerable disruption across the city: public transportation, including BART stations at Powell Street and Civic Center, and Muni and Central Subway systems, halted service. Critically, Waymo's autonomous ride-hailing service was temporarily suspended after many of its self-driving vehicles were observed stalled in darkened intersections, contributing to traffic congestion. While power began to be restored to a majority of customers by late Saturday night, about 21,000 customers remained without electricity into Sunday morning.

Why It Matters

This widespread power outage underscores the critical dependence of modern urban environments and emerging technologies, such as autonomous vehicles, on a robust and reliable infrastructure. The incident exposed a vulnerability in Waymo's self-driving system, which struggled to operate effectively without functioning traffic signals, prompting public discussion and potential regulatory scrutiny regarding the deployment of autonomous fleets in cities prone to utility failures. Furthermore, the disruption to public transit, businesses, and daily life during the busy pre-Christmas weekend highlights the significant economic and social impact that such infrastructure failures can have on a major metropolitan area.

Geographic Location

• San Francisco, San Francisco County, California, United States (widespread power outage affecting approximately 130,000 customers, public transportation disruptions, and Waymo vehicle strandings)
• 8th and Mission Streets, San Francisco, San Francisco County, California, United States (location of PG&E substation fire that contributed to the outage)
• Powell Street Station, San Francisco, San Francisco County, California, United States (BART station closure due to power outage)
• Civic Center Station, San Francisco, San Francisco County, California, United States (BART station closure due to power outage)