State authorities say there should be adequate power in California this summer, but heat waves or wildfires that damage transmission lines could lead to potential problems.
The agency that operates the state's wholesale power system said Monday that reliability could be "marginally" more challenging in Southern California, where the San Onofre nuclear power plant has been shut down since January 2012.
But the California Independent System Operator report presented a largely favorable forecast for electricity this summer.
Statewide, electricity supplies have increased from last year, including the addition of power from wind and solar plants.
The agency says it will call on consumers to conserve if local shortages emerge.