Hydrogen (H2) is a potentially emissions-free alternative fuel that can be produced from domestic resources. Although not widely used today as a transportation fuel, government and industry research and development are working toward the goal of clean, economical, and safe hydrogen production and hydrogen-powered fuel cell vehicles.
Hydrogen is the simplest and most abundant element in the universe. However, it is rarely found alone in nature. Hydrogen is locked up in enormous quantities in water (H2O), hydrocarbons (such as methane, CH4), and other organic matter. Efficiently producing hydrogen from these compounds is one of the challenges of using hydrogen as a fuel. Currently, steam reforming of methane (natural gas) accounts for about 95% of the hydrogen produced in the United States.