Looming Eclipse Poses Challenge For Solar-Reliant California

California now has enough solar energy to power almost 5 million homes, but not on August 21.

A solar eclipse will block out much of the sun to the state. Spokesperson Steven Greenlee of California ISO, which operates the electric grid, says the state’s increased reliance on solar presents a challenge.

"We haven’t had this much solar impacted at this degree before," says Greenlee.

Greenlee says energy regulators have spent about a year planning for the decreased daylight. That includes consulting with Germany, which relies heavily on renewable power and experienced its own eclipse in 2015.

To cope, California will have to partially rely on natural gas plants that replace solar at night and ramp them up and down to match the fluctuating sunlight.