LOS ANGELES — It will take more than the flip of a switch to replace power lost from the troubled San Onofre nuclear plant.
State energy officials have already warned of rotating blackouts in the region if a heat wave hits and San Onofre stays dark, and plans for replacement power remain shaky. Also, the loss of the nuclear plant makes it harder to import power into the San Diego area, where reliable energy transmission has long been at issue.
"There is the potential for service interruptions. I could definitely see some customers being curtailed," said Michael Shames, executive director of advocacy group Utility Consumers' Action Network.
The twin reactors located between San Diego and Los Angeles have been idled while investigators determine why tubing carrying radioactive water is eroding at an unusual rate, and the Nuclear Regulatory Commission chairman will visit the plant Friday to highlight the agency's concern over the ailing equipment.
San Onofre can generate enough electricity for 1.4 million homes, but it could take up to two months to restart two retired power plants in Huntington Beach that have been pinpointed as an important source of replacement power, officials said Wednesday.
The twin, natural gas-fired plants in Huntington Beach, in northern Orange County, were retired earlier this year. The gas line feeding the plants was severed and 3-foot holes were cut in the boilers.
The California Energy Commission has not received a request to restart, though state officials have identified it as a source of replacement power. Commission Deputy Director Roger Johnson said it might take up to two months for the operator, AES Corp., to work through steps to rekindle Huntington Beach.
Repairs to the boilers and other equipment could be completed within 30 days, predicted Barry Wallerstein, executive officer at the South Coast Air Quality Management District.
However, AES does not have a contract with the state to operate the units, and state agencies are still piecing together steps it would take to get the Huntington Beach units on line, Wallerstein added.
Stephanie McCorkle, a spokeswoman for the agency that operates the state's wholesale power system, the California Independent System Operator, did not dispute the possible two-month timeline.
"We are optimistic the units can be back in service in time for hot summer weather," she said in a statement.
Eric Pendergraft, president of AES Southland, which operates the plants, said the company had not received a formal request from the California Independent System Operator to restart them. He said repairs and negotiating a contract could proceed simultaneously, allowing a restart in about a month.
"We are sort of on hold," he said.
San Diego Gas & Electric counts on power from San Onofre to help the utility bring in electricity from elsewhere — it takes power to move power. Spokeswoman Jennifer Ramp said the loss of the plant can restrict power imports into San Diego area by up to 30 percent.
Without the nuclear plant "we are going to be reduced," she said, adding that the utility hopes a new, $1.8 billion transmission line will be completed by summer, which would help fill any shortages.
The visit to San Onofre on Friday by NRC Chairman Gregory Jaczko comes about two months after the Unit 3 reactor was shut down as a precaution after a tube break. Traces of radiation escaped, but officials said there was no danger to workers or neighbors.
The agency announced last week that the plant will remain offline while investigators determine why tubing in its massive steam generators is eroding quickly — and repair the problems.
The company has found that the tube wear is being caused by vibration and friction with adjacent tubes and bracing, however investigators don't know why that's happening.
Operator Southern California Edison has said 321 tubes with excessive wear will be plugged and taken out of service at the two reactors, well within the margin to allow them to keep operating.
"The agency is very concerned," NRC spokesman Victor Dricks said. "The steam generators are a vital and very important piece of plant equipment, so ensuring their integrity is important" to the company and the NRC.
Jaczko will be joined by U.S. Sen. Dianne Feinstein, D-Calif.
The plant's four steam generators each contain nearly 10,000 alloy tubes that carry hot, pressurized water from the reactors. The Unit 2 reactor was shut down for maintenance when workers discovered extensive wear on its tubing.
The tubes are a critical safety barrier — if one or more break, there is the potential that radioactivity could escape into the atmosphere. Also, serious leaks can drain cooling water from a reactor.
Last week, an environmental group claimed the utility misled the NRC about design changes that it said are the likely culprit in excessive tube wear. The report by nuclear consultants Fairewinds Associates, and produced for nuclear watchdog Friends of the Earth, warned that a more detailed study is needed on the tubing before the reactors are restarted.
Friends of the Earth issued a statement Wednesday with another environmental group, San Clemente Green, urging the chairman to make a "full determination" of problems at the plant. Meanwhile, some officials in nearby communities have been calling for the plant to shut down permanently.
The equipment is relatively new — the generators were installed in a multimillion-dollar makeover in 2009 and 2010.
The plant is owned by SCE, San Diego Gas & Electric and the City of Riverside. The Unit 1 reactor operated from 1968 to 1992, when it was shut down and dismantled.