Lawmakers grilled power executives over how they plan to make up the loss in power supply, now that a small but expensive-to-fix radiation leak has forced the permanent closure of the San Onofre Nuclear Generating Station.
The plant supplied energy to nearly 1.5 million homes in southern Orange and northern San Diego counties.
Upgraded transmission lines, increased generation from other facilities and consumer cutbacks help meet demand when things are running fine, but hiccups could spell trouble.
"We are limited in our ability to simply ship in additional power to meet demand," said state Sen. Alex Padilla (D-Pacoima), who chairs the Senate Energy Committee.
"We've taken a number of steps to make sure that we can handle the system at that point, but certainly things are going to be tight," said Steve Berberich, president and CEO of California Independent System Operator (Cal ISO).
Nuclear power doesn't emit greenhouse gasses. The other issue is whether the state can meet its goal of 33 percent renewable energy by 2020.
The idea is to slow the effects of global warming by boosting solar use, for instance. But since the closure of San Onofre's twin reactors, the state is going in the opposite direction.
"It shows that GHGs [greenhouse gas emissions] have increased since the shutdown," said David Mead, senior vice president, Southern California Edison.
Several cities in California are nuclear-free zones, so they're celebrating that the state is finally down to one nuclear plant located in San Luis Obispo.
"There's been a lot of PR in recent years about nukes being greenhouse-gas-free, but that's really a stretch of the imagination," said Jean Merrigan, Women's Energy Matters.
The challenge for state and utility leaders is to craft a plan that will meet both energy demands and environmental goals.