Southern California’s risk for blackouts up

The risk of electricity blackouts in Southern California during the hottest days this summer is more than triple that of previous years because power plant additions have failed to keep up with demand, the state’s grid manager said.

The likelihood of a Stage 3 emergency, when reserves dip below 3% and power is cut to some customers to prevent a system collapse, rose to 10% for Southern California from 3% in last year’s forecast, the California Independent System Operator said in a report Monday.

The state will have 489 megawatts of new generation in time for peak demand in July or August, some of that replacing a 122-megawatt plant that’s being retired. Southern California will need to rely on imports from Arizona, Nevada and Mexico, as well as conservation, to avoid blackouts.

Demand probably will increase by 1,000 megawatts this year over last year, Cal-ISO Chief Executive Yakout Mansour said during a conference call. Power demand peaked at 48,615 megawatts in 2007.

“Conditions will be more difficult” in Southern California, Cal-ISO said in its 2008 Summer Assessment. “Voluntary conservation and on-call interruptible loads could be needed more frequently than normal.”