SAN DIEGO, Sept. 9, 2011 /PRNewswire/ -- San Diego Gas & Electric (SDG&E) today restored power at 3:25 a.m. to its 1.4 million customers affected by the Sept. 8 outage.  The restoration was accomplished almost exactly 12 hours after a major electric transmission system outage in western Arizona and the loss of a key connection with the San Onofre Nuclear Generating Station and other factors resulted in the most widespread power outage in the company's history.  

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On Thursday afternoon and throughout the night SDG&E coordinated its restoration efforts with the organization in charge of California's power grid, the California Independent System Operator Corporation (ISO).  Early this morning, in cooperation with the ISO, SDG&E completed the power restoration process.  Because the restoration process went smoothly, SDG&E was able to restore power sooner than anticipated.

SDG&E thanks its customers for their patience and local public agencies, including local municipalities, for their support and cooperation.

"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 David Geier, vice president of electric operations.  "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. "

SDG&E and the ISO are focusing their efforts over the next few days on maintaining and ensuring the integrity of the local power system.  Upon meeting that goal, the company will turn its attention toward determining the sequence of events that led to the outage and establishing practices and procedures to ensure that outages such as the Sept. 8 event are not repeated.

There may be isolated outages that persist.  If customers are experiencing an interruption in electric service, they should all SDG&E at 1-800-411-SDGE (7343).

The ISO and SDG&E have called for energy conservation throughout the day Friday.  SDG&E is asking customers to: 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 power outage began with a major transmission outage in western Arizona that caused a loss of power to southern California.  Shortly afterward, the San Onofre Nuclear Generating Station went off line.  As a result, SDG&E did not have adequate resources on its system to keep power on across its service territory.

SDG&E is a regulated public utility that provides energy service to 3.5 million consumers through 1.4 million electric meters and more than 850,000 natural gas meters in San Diego and southern Orange counties.  The utility's area spans 4,100 square miles.  SDG&E is a subsidiary of Sempra Energy (NYSE: SRE), a Fortune 500 energy services holding company based in San Diego.  

SOURCE San Diego Gas & Electric