A hydrogen vehicle is a vehicle that uses hydrogen as its onboard fuel for motive power. Hydrogen vehicles include hydrogen fueled space rockets, as well as automobiles and other transportation vehicles. The power plants of such vehicles convert the chemical energy of hydrogen to mechanical energy either by burning hydrogen in an internal combustion engine, or by reacting hydrogen with oxygen in a fuel cell to run electric motors. Widespread use of hydrogen for fueling transportation is a key element of a proposed hydrogen economy.

Fuel cell vehicles use hydrogen gas to power an electric motor. Unlike conventional vehicles which run on gasoline or diesel, fuel cell cars and trucks combine hydrogen and oxygen to produce electricity, which runs a motor. Since they’re powered entirely by electricity, fuel cell vehicles are considered electric vehicles (“EVs”)—but unlike other EVs, their range and refueling processes are comparable to conventional cars and trucks.

Converting hydrogen gas into electricity produces only water and heat as a byproduct, meaning fuel cell vehicles don’t create tailpipe pollution when they’re driven. Producing the hydrogen itself can lead to pollution, including greenhouse gas emissions, but even when the fuel comes from one of the dirtiest sources of hydrogen, natural gas, today’s early fuel cell cars and trucks can cut emissions by over 30 percent when compared with their gasoline-powered counterparts. Future renewable fuel standards—such as the requirements currently in place in California—could make hydrogen even cleaner.