Most of the current hydrogen production in the U.S. is carried out by steam reforming natural gas (methane), which involves reacting steam with methane to generate H2. To make hydrogen a viable fuel source, more efficient ways of producing hydrogen on the large scale will be needed. Many scientists are currently investigating chemical and biological catalysts capable of carrying out a process called water splitting, which is the production of H2 and O2 from water (H2O). Water splitting may have the potential to make hydrogen into a viable fuel source for vehicles.
An experimental fuel cell car is shown here. Fuel cell technology has been deployed commercially in recent years, but is more often seen in public vehicles such as buses than in private cars.