Update: California Grid Operator Launches Investigation Into Massive Outage

Updated at 4:31 p.m. Friday.

A joint task force will be created to investigate the cause of the massive blackout that affected nearly 4 million customers in Southern California, the California Independent System Operator Corporation (ISO) announced on Friday.

According to a press release, the ISO and Western Electricity Coordinating Council will investigate the actions of all utilities impacted by the outage, including San Diego Gas & Electric Co., Arizona Public Service, Southern California Edison, Imperial Irrigation District and Comisión Federal de Electricidad in Mexico.

“Our first priority was to help restore electricity to customers in the San Diego area who were hard hit by this devastating blackout and we appreciate all the entities that teamed up to perform herculean efforts overnight,” said ISO President and CEO Steve Berberich. “We now turn our focus to root-cause analysis to investigate the reason for the series of events that triggered the widespread power outage.”

The Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC) will also join in the investigation that left much of San Diego County in the dark Thursday afternoon and into Friday morning.

The news of the investigation comes after SDG&E said that while it has restored power not all of its generating plants are operating yet and customers still need to limit electricity use.

At a noon press conference, SDG&E President Mike Niggli said residents still need to "continue their conservation efforts" as the "system is still fragile." Joined by San Diego County Board of Supervisors Chairman Bill Horn, San Diego Mayor Jerry Sanders and other regional leaders, Niggli added that the San Onofre plant was still down with hopes that it will operate again in 24-48 hours.

The call for energy conservation comes after the utility company announced early Friday morning that the restoration process was completed "almost exactly 12 hours after a major electric transmission system outage in western Arizona" that turned off the lights for about millions of customers in San Diego County, Orange County, Riverside County and parts of Arizona and Mexico. It is unclear how many customers are still without power.

As the restoration process continues, Niggli said his company, the ISO and other agencies will investigate the massive outage.

"We'll be looking at the data very carefully," he said. "There are mounds of data to look through. We can't be perfect in this area but we can try to get better with every single event."

Though the restoration came sooner than expected, officials asked customers to practice energy-saving tips as the system is "fragile."

“Restoring power in the aftermath of the loss of the entire local grid serving San Diego and southern Orange counties was a monumental task and the ISO, the region’s power plant managers and our employees really rose to the challenge,” said Vice President of Electric Operations David Geier. “The restoration process, however, has left our local power grid very fragile, and we are asking our customers to conserve electricity throughout the day Friday."

As San Diego County residents recover from the outage, California Independent System Operator Corporation and SDG&E are asking customers to practice the following throughout Friday:

• Set air conditioners to 78 degrees or higher.
• Use fans rather than air conditioning.
• Keep windows, doors and fireplace dampers closed when using an air conditioner.
• Turn off the air conditioner when leaving the house.
• Draw blinds and drapes to keep the sun out during the warmer parts of the day and open windows at night and during the cool of the day.

The outage was triggered when an Arizona Public Service employee carried out a procedure in the North Gila substation, located northeast of Yuma. SDG&E officials said the transmission outage in Arizona ultimately caused the San Onofre Generating Station to go off and "as a result, SDG&E did not have adequate resources on its system to keep power on across its service territory." The blackout was the largest in the company's history.

Customers from south Orange County to Arizona and Tijuana were affected in the "unprecedented" outage, which snarled freeways, halted phone and trolley service and knocked radio stations off the air. Camp Pendleton lost power while hospitals including Rady Children's were operating on backup generators. People stuck on SeaWorld rides and in elevators were also reported.

Public and Catholic schools throughout San Diego County canceled Friday classes. Metropolitan Transit System and the North County Transit System will operate regularly while county offices and courthouses will also operate on normal hours. San Diego County officials said the precautionary order to boil water before drinking is still in effect for the communities impacted by the power outages at the city of San Diego pump stations. Those communities include: Scripps-Miramar, Tierrasanta, San Carlos, Bernardo Heights, Scripps Ranch, La Jolla-Soledad, Otay Mesa and the College Grove area.

The county's Hazardous Materials Division says gas stations don’t have to observe permit requirements to “cold start” their underground storage tank monitoring systems. Those rules have been waived temporarily to speed the return of service, the county said.

Isolated outages may persist, and the company said customers experiencing an interruption in electric service should call SDG&E at 800-411-SDGE (7343). To help San Diegans, the county has an emergency preparedness website and SDG&E has tips on saving energy.

Ken Stone contributed to this report.