SolarCity to Use Batteries From Tesla for Energy Storage - NYTimes.com

An energetic family

"“We are providing them a solution to reduce their energy cost and demand cost,” said Lyndon Rive, SolarCity’s chief executive, adding that the systems would provide backup power and a working solar array during blackouts. Although he said he did not see the systems as a step toward independence from the grid, storage would be important to maintaining grid stability as more customers adopt solar.
The product grew from a $1.8 million grant in 2010 from the California Public Utilities Commission to study the possibilities of storing electricity from rooftop solar arrays in batteries. The company has also signed up about 300 of its residential customers for a pilot program using battery packs from Tesla, whose chief executive, Elon Musk, is the chairman of SolarCity and Mr. Rive’s cousin."

SolarCity to Use Batteries From Tesla for Energy Storage - NYTimes.com