A Volkswagen AG unmanned Audi RS7 automobile is driven on a track. In its efforts to bring autonomous-driving technology to the streets, Volkswagen AG's Audi is testing unmanned vehicles at speeds as fast as 190 miles per hour.
Credit Audi Ag. Despite the lofty goals, energy storage must overcome significant hurdles before it goes mainstream. Or, as Mr. Goldie-Scot put it, �A lot of the technologies still need to move beyond the proof-of-concept stage.