Natural gas is a domestically produced alternative fuel and is readily available to end users through the utility infrastructure. It can produce significantly fewer harmful emissions than gasoline or diesel when used in natural gas vehicles.
Natural gas is a mixture of hydrocarbons, predominantly methane (CH4). As delivered through the pipeline system, it also contains hydrocarbons such as ethane and propane and other gases such as nitrogen, helium, carbon dioxide, hydrogen sulfide, and water vapor.
Natural gas has a high octane rating and excellent properties for spark-ignited internal combustion engines. It is non-toxic, non-corrosive, and non-carcinogenic. It presents no threat to soil, surface water, or groundwater.
Most natural gas is extracted from gas and oil wells. Much smaller amounts are derived from supplemental sources such as synthetic gas, landfill gas and other biogas resources, and coal-derived gas.
Natural gas accounts for approximately one quarter of the energy used in the United States. Of this, about one third goes to residential and commercial uses, one third to industrial uses, and one third to electric power production. Only about one tenth of one percent is currently used for transportation fuel.
Natural gas vehicles (NGVs), which can run on compressed natural gas (CNG), are good choices for high-mileage, centrally-fueled fleets that operate within a limited area. For vehicles needing to travel long distances, liquified natural gas (LNG) is a good choice. The advantages of natural gas as a transportation fuel include its domestic availability, widespread distribution infrastructure, low cost, and clean-burning qualities.
CNG and LNG are considered alternative fuels under the Energy Policy Act of 1992. The horsepower, acceleration, and cruise speed of NGVs are comparable with those of equivalent conventional vehicles. And, compared with conventional diesel and gasoline vehicles, NGVs can produce some emissions benefits.