Compressed natural gas (CNG) is utility, pipeline-quality natural gas that has been compressed to 3,000 -3,600 pounds per square inch (psi). Compression allows more natural gas to fit into a smaller space, such as a vehicle’s fuel tank. It also allows the optimum amount of energy, commonly referred to as a British thermal unit or BTU, to be injected into an internal combustion engine.
Liquid Natural Gas (LNG) Versus CNG
In its natural state, natural gas is normally a gaseous, lighter-than-air substance – not a liquid. Natural gas can be compressed to 3,000 or 3,600 psi to form CNG or liquefied at -260° F to form liquefied natural gas (LNG). In either state, natural gas can provide the same BTU equivalent as conventional transportation fuels.
CNG is a preferred fuel for various vehicle applications, including light-duty vehicles, medium-duty trucks, school buses, transit buses and refuse vehicles. LNG, because of the higher energy density and longer vehicle fuel range, is more commonly utilized by heavy-duty semi-trucks for long-haul applications.
CNG is stored in tanks that meet stringent safety requirements on all vehicles. The carbon fiber fuel storage cylinders used in CNG vehicles are much stronger than gasoline fuel tanks. All natural gas cylinders are subjected to a number of federally required severe abuse tests, such as heat and pressure extremes, gunfire, collision and fire.
Natural gas fuel systems are pressure sealed, which prevents spills or evaporative losses. CNG’s lighter-than-air nature allows it to dissipate into the atmosphere in the unlikely event that a leak in the fuel system does occur unlike gasoline, which in the event of a leak or accident pools on the ground creating a fire hazard.
The usage of natural gas as a transportation fuel is actually safer than conventional fuels. Natural gas has a high ignition temperature, approximately 1,200° F compared with 600° F for gasoline. In addition, natural gas will not burn if it is mixed with too much or too little air. This can be compared to a flooded carburetor in a motorcycle. The motorcycle’s engine will not start until the ideal percentage of air exists to allow combustion. Natural gas will only burn when it is between a range of approximately 5% to 15% of the total volume of the air in which it exists. This high ignition temperature and limited flammability range make accidental ignition or combustion of natural gas very unlikely. Furthermore, static electricity fires and accidents involving gasoline emissions do not exist with natural gas because of its higher ignition temperature.
Before you convert your vehicle to run on natural gas or purchase a new or used CNG vehicle, be sure to investigate your fueling options. While there are more than 1,100 CNG fueling locations in the U.S., only approximately half are open to the public. Stations not open to the public are typically restricted for use by fleet operators. More natural gas fueling stations are being built across the country every day as demand for CNG vehicles continues to increase. The U.S. has millions of miles of natural gas pipelines in the ground, already providing the majority of the infrastructure necessary for a national network of CNG fueling stations. All that is lacking is the final compression and dispensing of the fuel to the consumer.
For a comprehensive map of public fueling stations, please visit CNGnow.com.
If your home has access to natural gas lines, it is possible to refuel overnight at home with properly installed equipment. Phill® by BRC FuelMaker enables you to refuel at home and save even more money on a gallon-equivalent basis. Well-known appliance manufacturers are also developing products that could be on the market by 2013.
Home CNG refueling devices may qualify for state tax incentives or grant subsidies.
These home fueling units are safe and easy to use. By connecting to the natural gas line found in your home and a source of electrical power, home fueling units slowly compress natural gas and deliver it to the storage tank in the vehicle overnight. When the driver arrives home in the evening, he or she simply plugs it in and the unit will automatically run until the tank is full. Using the same amount of power as a hot water heater or gas dryer, these units are efficient, safe and easy to use. A user’s fuel bill will be included in their monthly utility bill and will provide a convenient system for continuous use.
To locate a certified conversion company in your area, please visit ngvamerica.org or CNGnow.com.
Home CNG refueling devices qualify for a federal tax incentive of up to $2,000 and may also qualify for additional state tax incentives or grant subsidies. More information about available tax incentives can be found at http://www.ngvamerica.org/incentives/federalTax.html or by contacting the appropriate state authority. Conversion incentives vary from state to state. To find conversion tax incentives in your state, visit CNGnow.com.
For more information concerning CNG, visit CNGnow.com.
For those wanting to offer retail CNG, please contact CNGnow.com or visit ngvamerica.org.