MSNBC

Investors looking to get fabulously rich may want to place a few bets on solar cell and rechargeable battery technology. At least, that's one way to frame an onstage chat between U.S. Energy Secretary Steven Chu and billionaire Bill Gates at a recent energy innovation conference.

A combination of breakthroughs in solar and battery technologies will allow them "to go viral in the same way that cellphones went viral not only in the developed world, but also in the developing world," Chu said at the annual summit of the Advanced Research Projects Agency - Energy.