There are many fuels today being used in vehicles as "alternatives" to gasoline or diesel. In most instances, the alternative fuel is less polluting, resulting in fewer harmful emissions into the air and a lower negative impact on human health. Many cities and companies across the U.S. have adopted programs to use alternative fuels in their fleets. These same entities are encouraging efforts to provide the fueling infrastructure necessary to operate alternatively fueled vehicles. Clean Cities is one of those.

Biofuels

Biofuels are renewable fuels and the majority used in the U.S. are grown domestically, reducing our reliance on foreign energy sources. Corn ethanol and soy-based biodiesel are the most commonly used, have a positive net energy balance and some studies have shown burn more cleanly than gasoline or diesel. Biofuels may also be made from cellulosic biomass such as herbaceous and woody plants, agricultural and forestry residues, as well as municipal solid and industrial waste. Their use strengthens rural economies, decreases America's dependence on imported oil, reduces air and water pollution, and reduces greenhouse gas emissions. 

Biodiesel

Biodiesel in the U.S. is made primarily from soybeans, with some being produced from waste cooking oils and other materials. It is used in ratios as small as 5 or 10%blends, all the way up to 100% with the higher concentrations being considered an alternative fuel. 

Ethanol

The majority of ethanol produced in the U.S. is made from corn. Cellulosic-produced ethanol is gaining traction as that technology evolves. Although much ethanol is used in 10 or 15% blends with gasoline to create gasohol, it is also used in concentrations of up to an 85% blend with gasoline to create E-85 and currently referred to as an alternative fuel.

Methanol

Methanol is another alcohol-based fuel. Today most of the world's methanol is produced by a process using natural gas as a feedstock. The majority of methanol currently used as transportation fuel is M-85.

Batteries (Electric Vehicles)

Electric vehicle batteries are primarily charged from electricity that is produced at a central power plant, with its associated emissions.  Electric vehicles produce no tailpipe emissions and are generally more efficiency than conventional vehicles. 

Battery and Gasoline (Hybrid Electric Vehicles)

Hybrid electric vehicles (HEVs) combine the internal combustion engine of a conventional vehicle with the battery and electric motor of an electric vehicle, resulting in twice the fuel economy of conventional vehicles. Several automakers are currently selling this vehicles with this technology. The links below are from the U.S. Department of Energy's site FuelEconomy.gov.

Compressed Natural Gas

The interest for compressed natural gas as an alternative fuel stems mainly from its relatively clean burning qualities, its domestic resource base, and its commercial availability to end-users. Natural gas is primarily produced from gas wells or in conjunction with crude oil production. Compressed natural gas may also be generated from renewable sources using livestock waste or other organic waste through a process called anaerobic digestion.

Propane (LPG)

Liquefied petroleum gas (LPG) in the U.S. consists mainly of propane, but may also include propylene, butane, and butylene in various mixtures. LPG is produced as a by-product of natural gas processing and petroleum refining and is in gas form at normal temperatures and pressures. Most of the LPG used in the U.S. is produced domestically. Propane has been used as a transportation fuel around the world for more than 60 years. Missouri has approximately 320 propane fueling sites.

Solar

Solar energy is derived from the sun. In order to collect this energy and use it to fuel a vehicle, photovoltaic cells are used. Much research has gone into evaluating how solar energy may be used to power vehicles, however the long term possibility of operating a vehicle on solar power alone will depend on new technology development and is now used only to power certain auxiliary systems in the vehicle.