Way Cool Green Concept Vehicles - Photo Gallery

The BMW Hydrogen 7 steers through the ultra-clean hydrogen highway in a different direction—because it isn’t a fuel-cell vehicle. Instead of using hydrogen to generate electricity in a fuel cell, the BMW Hydrogen 7— essentially a 7 Series sedan—burns liquid hydrogen in its conventional V-12 engine. The Hydrogen 7’s tank acts like a giant thermos because the temperature of hydrogen must drop down to about 400 degrees below zero Fahrenheit before reaching a liquid state.