Alternative Fuels
When you drive an alternative fuel or flexible fuel vehicle, you don't have to rely entirely on petroleum as a fuel. You can use an alternative fuel designed for the vehicle. The alternative fuel will help reduce our dependency on imported petroleum and produce fewer harmful tailpipe emissions.
Alternative fuels include:
Biofuels
Biofuels are made from biomass. Today, biofuels used in vehicles are commonly blended with petroleum. For example, E85 is 85% ethanol and 15% petroleum. And B20—a biodiesel blend—is 20% biofuels and 80% diesel. Pure biodiesel (B100) can be used, but it currently requires engine modifications and may not be suitable for wintertime use.
Learn more about NREL's research in biodiesel and biochemical conversion technologies for producing ethanol from more than just starches and sugar.
See the U.S. Department of Energy Alternative Fuels Data Center for more information about biodiesel and ethanol.
Gaseous Fuels
Gaseous fuels aren't in liquid form. They're "gaseous" as their name suggests. Gaseous fuels include natural gas and hydrogen, as well as hydrogen-natural gas fuel blends.
There are two types of natural gas: compressed natural gas (CNG) and liquefied natural gas (LNG). Dedicated natural gas vehicles run only on natural gas. Meanwhile, bi-fuel natural gas vehicles have two separate fueling systems, which enable them to use either natural gas or petroleum.
Unlike natural gas, hydrogen is still evolving as a transportation fuel. Hydrogen has been used effectively in a number of internal combustion engine vehicles as pure hydrogen mixed with natural gas. But hydrogen fuel-cell vehicles aren't yet commercially available.
Learn more about NREL's research in gaseous fuels, including hydrogen.
See the U.S. Department of Energy Alternative Fuels Data Center for more information about hydrogen, natural gas, and hydrogen-natural gas blends.
Gas-to-Liquid Fuels
Gaseous fuels can be converted into liquid fuels, which can be refined into gasoline and diesel. These gas-to-liquid fuels are also known as Fischer-Tropsch fuels.
Learn more about NREL's research in gas-to-liquid fuels.
Electricity
Electricity can be used as a transportation fuel. It's used to power batteries in electric and plug-in hybrid electric vehicles. And fuel cell vehicles use electricity produced from an electrochemical reaction that takes place when hydrogen and oxygen are combined in the fuel cell "stack."
See the U.S. Department of Energy Alternative Fuels Data Center for more information about electricity as a transportation fuel.