Hydrogen fuel is used to power vehicles by running compressed hydrogen that is stored onboard with oxygen from the air to create electricity to power an electric motor.  Hydrogen produces nearly three times the energy per pound than gasoline; however, it has only about 1/10 the density in a liquid form. Therefore, a hydrogen fuel talk has to be much larger than a traditional gasoline tank.

In order to use hydrogen in a car, it has to be produced as it does not occur naturally in a quantity worth using. There are several methods for producing hydrogen including pulling the hydrogen out of water. Unfortunately, this process required a good deal of energy. A recent study completed at MIT found that "Even with aggressive research, the hydrogen fuel-cell vehicle will not be better than the diesel hybrid ( a vehicle powered by a conventional engine supplemented by an electric motor) in terms of total energy use and greenhouse gas emissions by 2020."