Natural gas vehicles (NGVs) are here today and repeatedly demonstrate their ability to surpass even the most demanding new emission requirements. Natural gas is available in every major urban market in the U.S. and it can play a major role in solving transportation pollution and foreign oil and gasoline supply problems.
The United States spends about $1.7 billion a day to pay for foreign oil. That's why making the U.S. less dependent on foreign oil is a national priority. Congress, on record as strongly supporting reduction of petroleum use, has passed a number of pieces of legislation to incentivize Americans to move to non-petroleum fuels. While in 2005, the U.S. imported over 65 percent of the oil it used, 97 percent of the natural gas used in the U.S. was produced in North America (85 percent from the U.S. and 12 percent from Canada). Every gallon equivalent of natural gas used in vehicles is one less gallon of petroleum that has to be imported.
Exhaust emissions from a typical NGV are much lower than those from gasoline-powered vehicles. For example, the natural gas-powered Honda Civic GX is recognized by the U.S. Environmental Protection Agency 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. In addition, dedicated NGVs produce little or no evaporative emissions during fueling and use. In gasoline vehicles, evaporative and fueling emissions account for at least 50 percent of a vehicle's total hydrocarbon emissions.
Typical dedicated NGVs can reduce exhaust emissions of:
- Carbon monoxide (CO) by 70 percent
- Non-methane organic gas (NMOG) by 87 percent
- Nitrogen oxides (NOX) by 87 percent
- Carbon dioxide (CO2) by almost 20 percent below those of gasoline vehicles
Natural gas vehicles also produce far less urban emissions than diesel vehicles. For example, even when the stringent 2007 EPA heavy-duty engine emission standards become applicable, NGVs will be producing only one-sixth of the NOX of comparable diesel engines.
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. Tests have shown that NGVs produce up to 20 percent less greenhouse gas emissions than comparable gasoline vehicles and up to 15 percent less than comparable diesel vehicles.
Compressed natural gas (CNG) unlike gasoline dissipates into the atmosphere in the event of an accident. In contrast, 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 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 of about 1,200 degrees Fahrenheit, compared with about 600 degrees Fahrenheit for gasoline. It also has a narrow range of flammability. In concentrations in air below about 5 percent and above 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.