Alternative Fuels and Vehicles

Many other alternative fuels are being used today in place of gasoline and diesel fuel, including:

• Natural gas – domestically produced and available to end-users through the utility infrastructure. It can either be stored onboard a vehicle as compressed natural gas (CNG) or liquefied natural gas (LNG). Natural gas also can be blended with hydrogen. 
• Electricity – stored in batteries or produced onboard.
• Propane – produced as a by-product of natural gas processing and crude oil refining.
• Liquids made from coal - gasoline and diesel fuel that doesn't come from petroleum.

Alternative-Fuel Vehicles

Alternative fuel vehicles (AFVs) use alternative fuels instead of gasoline or diesel fuel. AFVs range in size and shape, from small commuter cars to large 18-wheeler trucks. A number of automobile manufacturers offer light-duty vehicles for personal transportation.

AFVs are well-suited for fleets in certain "niche" markets. Taxi fleets, for example, with high-mileage vehicles that drive fairly centralized routes, may benefit from using a less expensive alternative fuel such as natural gas or propane. Local delivery fleets-with low mileage, high-use vehicles that frequently idle in traffic or must often start and stop may be good candidates for electric vehicles. Medium- and heavy-duty AFV applications include transit buses, airport shuttles, delivery trucks and vans, school buses, refuse haulers, and street sweepers.

AFV Types

• Flex-Fuel Vehicles can be fueled with gasoline or, depending on the vehicle, with either methanol (M85) or ethanol (E85). The vehicles have one tank and can accept any mixture of gasoline and the alternative fuel.
• Bifuel or Dual-Fuel Vehicles have two tanks—one for gasoline and one for either natural gas or propane, depending on the vehicle. The vehicles can switch between the two fuels.
• Dedicated Vehicles are designed to be fueled only with an alternative fuel. Electric vehicles are a special type of dedicated vehicle.
• Hybrid Vehicles combine the best features of two different energy sources, one of which is electric power. Until alternative fuels really catch on, hybrids can be a good choice. A hybrid gets about twice the fuel economy as a conventional car of the same size and capacity.

Plug-in hybrids will be available soon. These get about twice the fuel economy of a hybrid. A plug-in hybrid, running on biofuel (e.g., 85 percent ethanol) could almost entirely eliminate its use of petroleum.