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About Natural Gas Vehicles

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About Natural Gas Vehicles

    • There are about 110,000 NGVs on U.S. roads today and more than 11 million worldwide.
    • There are more than 1,100 NGV fueling stations in the U.S. – and about half of them are open to the public.
    • In the United States, about 30 different manufacturers produce 100 models of light, medium and heavy-duty vehicles and engines.
    • According to the American Public Transit Association, 27 percent of all new transit bus orders in 2008 were for natural gas. According to the association, about 18 percent of transit buses run on natural gas.
    • Natural gas costs, on average, one-third less than conventional gasoline at the pump.
    • Natural gas is sold in gasoline gallon equivalents (GGE). A GGE has the same energy content (125,000 BTUs) as a gallon of gasoline without ethanol.

Benefits of NGVs

Petroleum Displacement
Making America less dependent on foreign oil is a national priority. President Obama, in accepting his party’s nomination, established his own clear goals:

For the sake of our economy, our security and the future of our planet, I will set a clear goal as president: in 10 years, we will finally end our dependence on oil from the Middle East.

Congress, too, strongly supports reducing petroleum use, and has passed laws that provide to incentives to Americans who move to non-petroleum fuels. While the United States imports more than 60 percent of the oil it uses, 98 percent of the natural gas used in the U.S. was produced in North America. Every gallon equivalent of natural gas used in vehicles is one less gallon of petroleum that has to be imported.

Urban Emissions
Exhaust emissions from NGVs are generally much lower than those from gasoline-powered vehicles. For example, the natural gas-powered Honda Civic GX is recognized by the U.S. EPA as the cleanest commercially available, internal-combustion vehicle on earth.  The Civic GX is rated by the California Air Resources Board as meeting the very stringent AT-PZEV standard.  The CNG powered Civic produces 95% fewer emissions of non-methane hydrocarbons, and 75 percent less emissions of nitrogen oxides than its gasoline counterpart.  Dedicated NGVs produce little or no evaporative emissions during fueling and use. In gasoline vehicles, evaporative and fueling emissions account for significant portion of the emission associated with operating a vehicle.   

Replacing a typical older in-use vehicle with a new NGV provides the following reductions in exhaust emissions of:

  • Carbon monoxide (CO) by 70 percent – 90 percent
  • Non-methane organic gas (NMOG) by 50 – 75 percent
  • Nitrogen oxides (NOx) by 75 – 95 percent
  • Carbon dioxide (CO2) by 20 – 30 percent

The actual emission benefits of introducing natural gas vehicles into a fleet will vary depending on the type of NGVs used and whether the emission comparison is based on the emissions of the vehicles being replaced or new motor vehicles.  Fleets that replace in-use medium and heavy duty diesel vehicles with new natural gas vehicles will see the most significant reductions in emissions since medium and heavy duty trucks put out much more emissions than light duty vehicles.

Greenhouse Gases
Per unit of energy, natural gas contains less carbon than any other fossil fuel, and thus produces lower carbon dioxide (CO2) emissions per vehicle mile traveled. While NGVs do emit methane, another principle greenhouse gas, any increase in methane emissions is more than offset by a substantial reduction in CO2 emissions compared to other fuels.  Recent analyses estimate that NGVs produce up to 20 – 30 percent less greenhouse gas emissions than comparable diesel and gasoline fueled vehicles. 

For more information on the environmental benefits of NGVs, click here:

CNG, unlike gasoline, dissipates into the atmosphere in the event of an accident. Gasoline pools on the ground creating a fire hazard.

The fuel storage cylinders used in NGVs are much stronger than gasoline fuel tanks. The design of NGV cylinders are subjected to a number of federally required "severe abuse" tests, such as heat and pressure extremes, gunfire, collisions and fires.

NGV fuel systems are "sealed," which prevents any spills or evaporative losses. Even if a leak were to occur in an NGV fuel system, the natural gas would dissipate up into the air because it is lighter than air.

Natural gas has a high ignition temperature, about 1,200 degrees Fahrenheit, compared with about 600 degrees Fahrenheit for gasoline. It also has a narrow range of flammability, that is, in concentrations in air below about 5 percent and above about 15 percent, natural gas will not burn. The high ignition temperature and limited flammability range make accidental ignition or combustion of natural gas unlikely.

Natural gas is not toxic or corrosive and will not contaminate ground water.


Target Audience

Until an area develops an adequate natural gas fueling station infrastructure (as has already developed in Southern California), NGVs are most practical for fleets.  Fleets generally operate a number of vehicles that are centrally maintained and fueled.  They also travel more miles daily than the average personal use vehicle and therefore can take better advantage of the lower price per gallon of natural gas. Among the fleets where use of NGVs is already growing are:


  • taxi cabs
  • over-the-road trucks
  • street sweepers
  • ice resurfacers
  • transit buses
  • refuse haulers
  • school buses
  • delivery vehicles
  • airport shuttles
  • forklifts


SEE ALSO: About Natural Gas For Transportation