Rolling blackouts leave half a million powerless

LOS ANGELES – Sweltering heat and the loss of power from a key transmission line Thursday forced the utility serving Southern California to impose rolling blackouts, leaving as many as half a million people without power for about half an hour, officials said.

The California Independent System Operator, which operates the state’s electric grid, declared a transmission emergency at 3:57 p.m., said ISO spokeswoman Stephanie McCorkle.

About 30 minutes later, power was being restored to people subjected to the blackouts, she said.

It marked one of the most serious disruptions since the California power crisis in 2000 and 2001, when high demand, high wholesale energy costs, transmission glitches and a tight supply caused widespread problems including blackouts.

The ISO ordered Southern California Edison to reduce demand Thursday, prompting the temporary blackouts in areas of Fontana, La Puente, Cathedral City, Huntington Beach, Long Beach and Ontario, said Gil Alexander, a spokesman for the utility. The utility scattered the outages to those points east and south of Los Angeles.

If the problem had persisted, officials said they would have shifted the blackouts to other areas on a rotating basis.