Stage 1 Power Alert Is Declared

California lurched into its first electricity emergency of the year Wednesday because of high temperatures around the state as well as power plant and transmission line outages.

The Stage 1 emergency, which meant the state was within 7% of running out of electricity, came a day after energy officials said California had adequate supplies for the summer but that serious generation or transmission mishaps could prompt blackouts.

Under California’s three-stage emergency alert system, the state Wednesday was far from declaring blackouts. But the emergency declaration underscored the fragile balance between supply and demand only two years after the energy crisis.

The California Independent System Operator, which runs the transmission grid for much of the state, said the pre-summer emergency was sparked by higher-than-forecast temperatures that sent usage soaring to more than 39,490 megawatts in the late afternoon, 4,500 megawatts more than anticipated.

In addition, electricity supplies were reduced.

Power plants capable of generating nearly 3,300 megawatts of electricity were turned off for maintenance and an additional 2,800 megawatts were unavailable because of outages. A megawatt serves on average about 750 homes.

Two major transmission lines also were operating at reduced capacity because of repairs and other factors.

Late May is a tricky time for the electricity grid because many generators are doing last-minute repairs before June 1, Cal-ISO spokeswoman Stephanie McCorkle said. When the weather turns unseasonably hot, the grid can be caught short, she said.

Although Wednesday’s emergency does not mean that the supply picture has taken a turn for the worse, energy planners at Cal-ISO, which balances supply and demand on the electricity grid every four seconds, were troubled by the late-afternoon usage spike, McCorkle said. That indicates that customers turned on their air conditioners, backsliding on the conservation habits they learned during the crisis of 2000-01, she said.

“We’re going to see many more hot days and the air conditioner rush hour is setting in,” McCorkle said. “It is a reminder that we don’t have tons of megawatts to work with and we do need to watch our electricity usage.”