So far SMUD has installed 15 batteries in homes already outfitted with solar panels in Rancho Cordova.
The lithium battery can store nearly 8 kilowatt hours of the photovoltaic solar electricity, plenty to power the home through cloudy patches or nighttime electricity use.
Mark Rawson with SMUD says the battery is programmed to calculate when to store up solar energy and when to send out the power:
RAWSON: "It looks at what's happening with solar production, the customer's home loads, and it turns itself from charging to discharging real quickly, to smooth out that variable PV production."
Rawson says this battery is the first of its kind in the nation. It's about the size of a small filing cabinet, and fits in the garage. Each battery cost about $25,000, but Rawson says if the technology is developed, the cost could come down significantly.