Alternative Transportation Fuels and Vehicles: Energy, Environment, and Development Issues [Updated January 9, 2004] [open pdf - 258KB]
"For many reasons, the United States has searched for alternatives to petroleum fuels. These reasons include limiting dependence on imported petroleum, controlling the emissions of pollutants into the air, and limiting the emissions of greenhouse gases. Several fuels are considered alternative transportation fuels by the federal government. These fuels are electricity, natural gas, propane (liquefied petroleum gas, or LPG), ethanol, methanol, biodiesel, and hydrogen. Some of these fuels are similar to conventional fuels, and can be used in conventional vehicles with little or no modification to the vehicle. However, some of these fuels are significantly different, and require the use of completely different engine, fuel, and drive systems. Consequently, cost as well as performance of the associated alternative fuel vehicles (AFVs) must be part of the discussion. Key factors in the ultimate success or failure of any alternative fuel include the relative cost of the fuel, the ability to develop and expand fueling stations, and the performance and safety of the fuel. For various reasons-notably cost, performance, and availability-alternative fuels have yet to play a major transportation role in the United States. Many argue that the government must step in. Congress, recent Administrations, and state governments have instituted some key programs to promote the use of alternative fuels. These programs include tax incentives for the purchase of alternative fuels and alternative fuel vehicles (AFVs), purchase requirements for government and private fleets, and research grants for the study of alternative fuels. Despite these efforts, only 0.2% of motor fuel demand (131 billion gallons of gasoline and 35 billion gallons of diesel) is met by alternative fuels today."
CRS Report for Congress, RL30758