Rocket science long dismissed as too impractical and expensive for everyday cars is getting a push into the mainstream by Toyota, the world's top-selling automaker.

Toyota Automotive Operations Senior Vice President Bob Carter speaks during a press event for the Toyota fuel cell concept vehicle in Las Vegas.

Buoyed by its success with electric-gasoline hybrid vehicles, Toyota is betting that drivers will embrace hydrogen fuel cells, an even cleaner technology that runs on the energy created by an electrochemical reaction when oxygen in the air combines with hydrogen stored as fuel.