California Dealing With 'Duck Curve' Solar Surplus

California has what sounds like a great problem to have. It's reached the point where it’s sometimes making too much solar energy. 

Elliot Mainzer explained to NBC News that during certain times of the year, the state creates more energy than it can use. He's the CEO of California’s Independent System Operator. 

That surplus of solar makes what experts call a “duck curve” of demand. That means demand for solar dips so far below supply that it looks like the hanging belly of a duck when graphed.

California has dealt with the sunshine windfall by sending energy along power lines to other states. Those states are happy to take the clean energy. Yet the state has installed so many solar panels that even shipping and storing all the excess energy is impossible.  

In 2024, California has made 2.6 million megawatts of solar energy above what it can use or export. That power is enough to meet energy demands in San Francisco for a year. But it ends up fizzling out. The power gets stranded in power stations. And some of it goes unharvested from solar panels.  

The solution? Add more batteries, experts say. But people rarely do so because of their high cost.  

“It’s an expensive fix,” Ed Murray said of the batteries. He's president of the California Solar and Storage Association. The batteries can cost up to $20,000 to install.