Diesel Backup Generator Population

BY STEVEN J. MOSS

The San Francisco Bay Area continues to host a steadily growing hive of dispersed diesel generators; those low buzzing big boxes located at internet server farms, hospitals, police stations, and, during festivals, Golden Gate Park.

In 2019, roughly 6,500 backup generators, known as “BUGs,” were littered across the region, able to produce a collective 3.8 gigawatts (GW) of power. In 2021 – less than three years later – BUG deployment had reached 8,722 generators, 4.8 GW of power, a 34 percent jump in the backup generator fleet.

By the end of 2022 the Bay Area’s BUG population totaled 9,121, with a collective capacity of more than five GW. Ninety percent of these gensets are diesel powered.

San Francisco is a fertile nesting ground for BUGs. In 2019 there were some 800 in the City. Today there are 1,208, with a combined generating capacity of 736 megawatts, enough to power all of San Francisco’s homes and businesses on a mild spring day.

These numbers exclude the thousands of smaller gasoline, propane, and diesel-powered generators located in backyards and garages. All emit polluting air emissions, much of which may go undetected by air quality regulators.

The engines mostly sit idle, waiting to be called on during an electricity grid