Instead of burning fuel like conventional engines, hydrogen fuel cells work through an electrochemical process. To produce electricity, hydrogen atoms are ionized on one side of an electrolyte membrane. While protons slip through, electrons must take the long way around through an external circuit, creating an electrical current as they move. Once the electrons reach the other side and pair off with the protons, the hydrogen combines with oxygen in the air, resulting in a little bit of heat and water as byproducts.
Scientists are focusing a lot of research -- and money -- on biofuel technology. The good news is the fuels are out there and in general, they're sustainable and better for the environment than fossil fuels. But they still have their downfalls, one being they're still expensive to produce. Read on to find out more about five of the "cheapest" biofuels.
The search for alternative fuel is on. Could a pocket-sized version of a nuclear power plant make your car run 5,000 miles (8,047 kilometers) between fill-ups?