By Anne Mulkern, E&E.

The head of the California agency keeping the state on track to meet its ambitious climate goals didn't rule out the long-term use of natural gas yesterday but said she also sees caveats on the horizon.

California Air Resources Board Chairwoman Mary Nichols, speaking at the VerdeXchange 2015 conference here, rejected the premise of the panel she was on, dubbed "Natural Gas -- Part of the Problem or Part of the Solution?" ARB is "fuel neutral," she said, when the agency looks at cutting greenhouse gas emissions. The Golden State aims to shrink those to 1990 levels by 2020, and 80 percent below 1990's point by 2050.