State utility officials say greenhouse gas emissions have risen since the shutdown of Southern California's San Onofre nuclear power plant last year.
An official with Southern California Edison, which owns the shuttered plant, told lawmakers Wednesday that 30 percent of the utility's electricity was from carbon-free resources last year.
That's a decline from 2011, when San Onofre was still running, and 50 percent of its electricity came from carbon-free nuclear, hydroelectric and renewable sources.
Energy officials addressed California lawmakers at a hearing on the shuttered plant in the state Capitol.
San Onofre was responsible for one-fifth of the electricity used by San Diego County and southern Orange County. Lawmakers are trying to figure out how to replace its capacity.
Edison announced June 7 that it was permanently closing San Onofre.