Attendees take pictures of the new Tesla Energy Powerwall Home Battery during an event at Tesla Motors in Hawthorne, California

Attendees take pictures of the new Tesla Energy Powerwall Home Battery during an event at Tesla Motors in Hawthorne, California April 30, 2015. Tesla Motors Inc unveiled Tesla Energy – a suite of batteries for homes, businesses and utilities – a highly-anticipated plan to expand its business beyond electric vehicles. REUTERS/Patrick T. Fallon – RTX1B28Q