Just about everybody agrees that we would be better off using hydrogen instead of gas for fuel. For starters, hydrogen makes water vapor instead of carbon monoxide when it's burned. But building a safe, efficient hydrogen vehicle is another matter. Enter the Aqwon, the first hydrogen-powered scooter to meet Germany's stringent regulatory standards. The Aqwon can hit 30 m.p.h. with its two-stroke engine, but the biggest challenge was building a fuel tank that could safely store the hydrogen. In case of accident or fire, the Aqwon's tank simply freezes. If only the Hindenburg had had one of those.
Availability: Prototype only. Estimated cost: $6,400
To Learn More: aqwon.com
Next Ice Bike