San Diego Utility Restores Power to California Households
September 09, 2011, 9:27 AM EDTBy Lars Paulsson, Lynn Doan and Michael B. Marois
(Updates with power restorations starting in first paragraph.)
Sept. 9 (Bloomberg) -- Sempra Energy’s San Diego Gas & Electric restored electricity to its customers after a transmission line failure yesterday caused the biggest blackout in the company’s history, cutting power to 1.46 million homes.
Power returned to its Southern California customers at 3:25 a.m. local time, almost 12 hours after the loss of a line that brings power from Arizona, the company said in a statement posted on its website today. The blackout also affected 56,000 customers in Arizona.
The fault snarled traffic, crippled emergency response systems and knocked out President Barack Obama’s televised speech. The blackout hit San Diego just before rush hour, on the night Obama addressed Congress on jobs and the economy and the pro-football season kicked off. California commuters languished as traffic lights went out and emergency services were hampered as the utility lost power to its entire service area.
The restoration process “has left our local power grid very fragile and we are asking our customers to conserve electricity throughout the day,” David Geier, vice president of electric operations for the San Diego-based utility, said in the press release.
San Diego temperatures are forecast to reach as high as 78 degrees Fahrenheit today (26 Celsius), according to AccuWeather.com data on Bloomberg.
‘Initiating Event’
Power for Arizona customers was restored at 9:10 p.m. local time last night, Damon Gross, a spokesman for Phoenix-based Pinnacle West Capital Corp., said in a phone interview today.
The blackout was caused by the failure of a 500-kilovolt electric transmission line near Yuma, Arizona. Pinnacle West’s Arizona Public Service, one of the line’s owners, is investigating why safeguards failed to isolate the problem.
“We believe that the initiating event was some work one of our employees was performing at a substation,” Gross said. “What we’re not clear about was why whatever happened there ultimately spread so far.”
Power grids are supposed to be able to withstand loss of the most important piece of equipment or power supply, Matthew Cordaro, a former Long Island Lighting Co. executive based in Shoreham, New York, said in an interview today. The blackout suggests that grid equipment, design or operation still can’t cope reliably with high flows of power between states, such as between Arizona power plants and Southern California, he said.
Cascading Blackout
“Once this line went out, it cascaded and overloaded other lines,” Cordaro said. “It’s not supposed to happen.”
The Federal Energy Regulatory Commission and North American Electric Reliability Corp. will investigate the blackout under regulations adopted after the 2003 Northeast blackout that cut power to as many as 50 million people in the U.S. and Canada, said Cordaro, an executive adviser to Paulus, Sokolowski & Sartor LLC, an engineering firm based in Warren, New Jersey.
NERC, based in Princeton, New Jersey, has legal authority to enforce rules aimed at averting blackouts under a 2007 federal order. Investigations by Arizona and California utility regulators and by the California power-grid operator also are probable, Cordaro said.
Unraveling the causes of a cascade blackout takes time, Cordaro said. The FERC and NERC study of February rolling blackouts in Texas took six months. The final report on the Aug. 14, 2003, blackout appeared in April 2004.
Planes, Trains
The blackout affected departing planes yesterday at San Diego International Airport, which handles about 300 flights daily. The airport is open and operating, said Angela Shafer- Payne, vice president of planning and operations for the airport authority. Some airlines canceled flights yesterday, unsure when power would return, she said.
Amtrak is resuming service between Los Angeles and San Diego, after trains were canceled because of the loss of power, according to an e-mailed statement today.
The power line, also owned by SDG&E and the Imperial Irrigation District, carries electricity from Arizona to Southern California.
Edison International’s twin nuclear units at San Onofre, California, also shut down, leaving about 2,000 customers in Riverside and Orange counties without power, Charles Coleman, a spokesman for the Rosemead, California-based utility, said in an e-mail yesterday.
The failure caused no safety problems at San Onofre, said Gil Alexander, a spokesman for the utility.
Power Conservation
The California Independent System Operator, which runs the state’s electricity grid, suspended its wholesale power market at 6 p.m. local time yesterday “due to a transmission emergency.” The administrative price is set at $250 per megawatt-hour.
The ISO asked people yesterday to conserve power and for customers without power to turn off air conditioners and appliances to protect against surges.
Laureen Salvagnini, a Maryland resident, said her daughter and grandson in Yuma retreated to their car to keep cool in the 118-degree heat.
“They don’t have AC, so where can they go to get out of the heat?” Salvagnini said in an e-mail. “We are dealing with flooding here in Maryland and she’s with no power.”
Residents of San Diego were caught off guard. A mile-long (1.6-kilometer) commute home from her Solana Beach office, north of San Diego, took about an hour, said Rachel Kay, president of Rachel Kay Public Relations.
Barbecuing Food
“I saw tons of sirens and cops but I’m not sure where they were going,” she said. “Fire engines were blazing.”
Kay, reached by telephone at home yesterday, said she was barbecuing the food in her refrigerator before it went bad and said her neighbors were doing the same.
“Living in San Diego, I think most of us don’t have personal emergency plans, we just don’t have severe weather,” she said. “I don’t know where my flashlights are, I don’t have bottled water and I don’t have food after today.”
People were turning to their car radios for news, Jim Farley, chief executive officer of Leichtag Family Foundation in Carlsbad, said. Farley said he remained in his office near Legoland for a while after the lights went out, and canceled a charity reception at the La Costa resort.
Florida Blackout
In February 2008, a field engineer diagnosing a malfunctioning switch on a substation in west Miami caused cascading power failures that affected 4.5 million customers in South Florida for hours. NextEra Energy Inc.’s Florida Power & Light agreed to pay a $25 million civil penalty as part of a settlement with the Federal Energy Regulatory Commission.
The biggest blackout in the U.S. occurred on Aug. 14, 2003, triggered by the loss of several transmission lines in the U.S. Midwest. Those failures caused additional lines and plants to go out of service and disrupted power to households in eight states and Ontario.
--With assistance from Anthony Palazzo, Rob Golum, Michael White and John Gittelsohn in Los Angeles, Mark Chediak and Rachael King in San Francisco, Jim Polson and Jessica Resnick-Ault in New York and Christian Schmollinger in Singapore. Editors: Tina Davis, Jessica Resnick-Ault
To contact the reporters on this story: Lars Paulsson in London at lpaulsson@bloomberg.net; Lynn Doan in San Francisco at ldoan6@bloomberg.net; Michael B. Marois in Sacramento at mmarois@bloomberg.net
To contact the editor responsible for this story: Anthony Palazzo at apalazzo@bloomberg.net
