Edison officials have said it is unclear whether a mechanical fix could be implemented to allow the plant to run at full capacity again. But a number of experts said they doubted that would make economic sense. Replacing the steam generators would be even more costly.
"It seems really unlikely that they are going to do that again. I think that they are going to be running at a lower rating and there will be lawsuits about that," said Meredith Angwin, a former steam generator project manager at the Electric Power Research Institute.
The extended shutdown has also sparked debate about whether Southern California's power grid relies too much on San Onofre.
The plant can power about 1.4 million homes — it also plays a crucial role in "voltage support," facilitating the importation of electricity from elsewhere.
Energy officials say that with contingency plans in place, including bringing some mothballed generators at a power plant in Huntington Beach temporarily back online, Southern California should be able to get through a San Onofre-free summer without blackouts. But those fixes are temporary.
State Sen. Alex Padilla (D-Pacoima), chairman of the Senate's energy committee, said Edison and state officials should have had a backup plan before problems struck.
State officials, he said, need to talk about long-term scenarios for California's energy grid, including a future without San Onofre.
But replacing the plant may be difficult and politically problematic, experts said. Property owners tend to balk at unsightly transmission lines, and new fossil fuel plants raise air quality concerns.
Some have argued that San Onofre should be replaced by renewables, but experts on California's grid say that is not immediately practical.
"Renewables aren't a steady stream of supply. You have to have power to back up the renewables, and you have to have it in the right place," said Fred Pickel, an energy industry consultant recently appointed ratepayer advocate for the city of Los Angeles.