On
a gallon-equivalent basis, natural gas costs an average of 15 to 40 percent
less than gasoline and diesel. Natural gas is a clean-burning fuel that reduces
vehicle maintenance.
Natural gas, unlike liquid fuels, cannot be siphoned from a vehicle. Fuel theft
is an on-going concern of fleet managers.
Vehicles
can be "fast filled" in five to six minutes using compressed gas stored
in cascades of natural gas cylinders or fueled overnight on a "timed fill"
basis in about five to eight hours.
Many private fleet fueling stations use a combination of fast fill and timed
fill.
Emissions
Natural gas is the cleanest burning alternative fuel. Exhaust emissions from NGVs are much lower than those from gasoline-powered vehicles. For instance, NGV emissions of carbon monoxide are approximately 70 percent lower, non-methane organic gas emissions are 89 percent lower, and oxides of nitrogen emissions are 87 percent lower. In addition to these reductions in pollutants, NGVs also emit significantly lower amounts of greenhouse gases and toxins than do gasoline vehicles.
Dedicated NGVs produce little or no evaporative emissions during fueling and use. For gasoline vehicles, evaporative and fueling emissions account for at least 50 percent of a vehicle's total hydrocarbon emissions. Dedicated NGVs also can reduce carbon dioxide exhaust emissions by almost 20 percent.
Exposure to the levels of suspended fine particulate matter found in many U.S. cities has been shown to increase the risk of respiratory illness. Diesel exhaust is under review as a hazardous air pollutant. Natural gas engines produce only tiny amounts of this matter.
Source - The Natural Gas Vehicle Coalition / http://www.ngvc.org