Hydrogen fuel cell cars are eco-friendly, but they come at a steep cost: hydrogen is normally expensive to make and store. Nissan, however, thinks it has a solution. It's developing a fuel cell system that will use bio-ethanol (generated from crops like corn and sugarcane) as a hydrogen source when it reaches vehicles in 2020. The technology combines the transformed bio-ethanol with air to power an electric motor. You're theoretically getting a "carbon-neutral" car with much more range than a pure EV -- Nissan is aiming for 497 miles on a tank where even the best Tesla Model S runs out of power at 294 miles. And since you wouldn't need to store hydrogen, you wouldn't need either giant tanks inside cars or special fuel stations.