CALIFORNIA (Ryan Flinn and Alan Ohnsman / Bloomberg).- Three employees of Tesla Motors Inc., a maker of battery-powered autos, died in a plane crash in California’s Silicon Valley that knocked out electricity to companies including Hewlett-Packard Co. and Facebook Inc.

The twin-engine Cessna 310 crashed about 8 a.m. yesterday in East Palo Alto, shortly after taking off in fog from Palo Alto Airport. Tesla Chief Executive Officer Elon Musk said the victims’ names were being withheld while relatives were notified. No injuries were reported on the ground.

“Tesla is a small, tightly knit company,” Musk said in an e-mail. “This is a tragic day for us.”

Yesterday’s accident came as San Carlos, California-based Tesla prepares to sell shares to the public, announce the location of its U.S. auto-assembly site and, later this year, move its headquarters to Palo Alto. Tesla has more than 500 employees and has delivered about 1,000 of its $109,000 Roadsters to buyers such as actor George Clooney.

Electricity was cut across Palo Alto, affecting about 28,000 customers and forcing Stanford Hospital and Lucile Packard Children’s Hospital to rely on emergency systems as crews worked to restore power.

“The plane when taking off struck a power tower,” East Palo Alto Police Captain John Chalmers said. “One of the wings came off and hit a residential structure.”