Soaring Temperatures Prompt Power Emergency
Less than a month after scattered power blackouts hit the Southland, unexpectedly high temperatures helped trigger another electricity emergency Monday as customers cranked up their air conditioners, straining already tight supplies.
The surge in power usage, along with the loss of several power plants, pushed reserve electricity levels below a 7% buffer and forced grid operators to declare a Stage 1 emergency that was expected to last from 1:50 to about 8 p.m.
Customer service is not interrupted and blackouts aren’t expected during a Stage 1 emergency. But the declaration prompts public calls for energy conservation and allows officials to tap electricity from other utilities and private generators that agree to help out in an emergency, California Independent System Operator spokesman Gregg Fishman said.
The last Stage 1 alert was issued May 28, which was the only power emergency for the year. Earlier this month, however, customers in Southern California got hit with the state’s first blackout since the energy crisis of 2000-2001.
On March 9, Southern California Edison Co. cut power off to 70,000 customers for 20 minutes in the evening after temperatures soared and electricity ran short. The emergency arose so unexpectedly that Cal-ISO, which manages most of California’s power grid, didn’t have time to warn power consumers.
Employees at Cal-ISO were to blame for not calling on extra supplies fast enough to handle rising demand, according to a follow-up report.
Much of Monday’s problem also stemmed from blistering temperatures, which surged 10 to 12 degrees past expected highs, topping out at 94 in downtown Los Angeles and 96 in Simi Valley, the local hot spot. The scorching weather pushed usage over forecasts by about 1,000 megawatts, enough energy to power 750,000 to 1 million homes, according to Cal-ISO.
Electricity supplies were further constrained by the unexpected shutdown Monday of Southern California generation units owned by Wildflower Energy, Dynegy Inc. and AES Corp., as well as reduced output at a few other sites, according to a Cal-ISO outage report.
In addition, many power plants have been down for planned maintenance, including one unit at the San Onofre Nuclear Generating Station, a big power producer that has been offline for more than a month for refueling, said Gil Alexander, a spokesman for part-owner Southern California Edison Co., a unit of Edison International in Rosemead.
By mid-afternoon, Cal-ISO officials believed they had rounded up enough extra power to handle the day’s second uptick in electricity use from 5 to 7 p.m., when residents arrive home from work and turn on lights, televisions and appliances.
“It doesn’t take very long for a few extra degrees in temperature to add up to a lot more energy usage,” Fishman said.
“But we called on extra resources for generation as well as transmission, and they responded to that, and we were able to serve the load in Southern California.”
If the situation were to worsen unexpectedly, Cal-ISO could move to a Stage 2 alert, in which power is curtailed to customers that agree to voluntary power interruptions, or to a Stage 3 alert, in which blackouts kick in to keep the electricity grid from collapsing.
