• By The Financial District


Hundreds of thousands of residents across California experienced rolling blackouts Friday night as state officials and utility crews worked to meet energy demands during a statewide heat wave, the California Independent System Operator said.

California ISO, which monitors the state’s electricity needs and power grid capabilities, issued a Stage 3 System Emergency because there was an electricity reserve deficiency, KCRA 3 News reported.

“The ISO is unable to meet minimum contingency reserve requirements, and load interruption is imminent or in progress,” the agency said about a Stage 3 emergency.

The energy emergency was declared around 6:30 p.m. and lifted by 11:15 p.m. California ISO data showed at 11:15 p.m. that the state has 48,242 megawatts of electricity with the current demand at more than 34,600 megawatts. During the peak usage time, around 7 p.m., the data showed demand was at 46,777 megawatts. The forecasted peak for Friday was 46,824 megawatts.

During the Stage 3 energy emergency, utility companies across California were directed by California ISO to conduct rotating power outages in order to relieve strain on the electrical power grid — that included PG&E.

"Pacific Gas and Electric Company (PG&E) has been directed by the California Independent System Operator (CAISO) to turn off power to approximately 200,000 to 250,000 customers at a time in rotating power outages given the strain on the power grid during the statewide heatwave," PG&E said in a statement about the energy emergency. "Other power utilities in the state are being directed to take similar actions."

PG&E said the rolling power outages were completed by 10:30 p.m. and power was essentially restored to all customers. The outages were expected to last for about an hour during each rotation, the utility said.

PG&E's rotating blackouts impacted El Dorado, Marin, Napa, San Mateo and Sonoma counties.

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PG&E said due to the emergency, officials were not be able to notify customers in advance about an outage. This is not a public safety power shutoff. PG&E explained the power shutoffs are "conducted during specific high fire threat conditions."

SMUD, which manages power to the Sacramento County area, said it was not asked to conduct rolling blackouts.

The California Office of Emergency Services created a power outage dashboard that allowed people to track the rolling blackouts. The data showed more than 20,900 customers are without power, as of 11:35 p.m.

"We are in close contact with [California ISO] following their declaration of a statewide energy emergency due to high electricity use during the hot weather," the California Office of Emergency Services said in a tweet. "OES is working with utilities & local officials to minimize the impact to Californians during potential rotating outages."