Conservation curbs Calif. energy crunch

California residents and businesses turned off lights, air conditioners and machinery Thursday to help the state weather an electricity shortage caused by soaring temperatures and high demand.

The state's largest energy consumers had been notified that they might have to go dark to help prevent blackouts, but the mandatory interruptions at industrial, commercial and retail businesses were not needed.

"Residents really responded and we want to thank them," said Stephanie McCorkle, spokeswoman for the California Independent System Operator. "The conservation we saw today from Californians saved the equivalent of a large power plant."

It appeared earlier in the day that energy demand might approach the state's all-time record, but the state's power usage peaked at 47,843 megawatts, well below the predicted peak of 49,105 megawatts.

Pacific Gas & Electric Co. spokeswoman Jennifer Ramp said the utility asked 2,200 large customers with which it has standing conservation agreements to reduce energy use voluntarily. Those reductions saved 600 megawatts, she said.

Despite the reprieve, triple-digit temperatures and high energy demand caused localized failures.

An overburdened distribution station in the San Fernando Valley triggered a rolling outage that affected about 2,000 Los Angeles Department of Water and Power customers. Residents were told they'd be without power for 1 1/2 hours, then have power switched back on for about 45 minutes before they would lose it again, spokeswoman Gale Harris said.

Another 1,500 utility customers lost power in other parts of the city, Harris said.

The California Independent System Operator, the agency that manages most of the state's electric grid, extended a statewide energy warning into Friday, marking a fourth consecutive day in which it projected high demand and urged conservation efforts.

Most of California's vast Central Valley was expected to have temperatures well over 100 degrees, with parts of the Los Angeles region also forecast to hit 100. Much of the San Francisco Bay area also is expected to be warmer than normal.