Propane (Autogas) vs. CNG (Compressed Natural Gas)
A Comparison of Alternative Fuels
Both CNG and propane are attractive, viable alternative fuels for the commercial fleet market, though customers often ask – what are the main differences between the two fuels?
Both fuels are greener and more cost effective than gasoline and diesel, though propane is often viewed as the gateway alternative fuel due to its attractive price point, availability and storage benefits. CleanFUEL encourages customers to examine the benefits of both options. It is also important to keep in mind that more alternatives will be added to the fuel menu in coming years as new technologies are developed. In the meantime, below are several key points that should be considered when comparing propane and CNG.
• CNG refueling stations can cost up to 10 times more to implement than a propane station. The environmental footprint of a CNG station is 10 times greater than a propane station based on the electricity required to store and pump the fuel.
• CNG storage tanks are required to be four times as large as propane tanks, while the operating pressure of a CNG tank is 17 times the pressure of a propane tank.
• The CNG storage size combined with the extreme pressure requires more space and fuel to transport than propane. Heavier storage tanks also contribute to greater pressure and demands on vehicles, which increases maintenance costs.
• The pressure involved in CNG storage also places a limit on how much fuel can be injected into a vehicle during one given time, creating a time-intensive refueling process for the vehicle owner.
• The cost of converting a vehicle to run on CNG is 50 percent more than the cost of converting a vehicle to propane.
• CNG is methane, a greenhouse gas, as opposed to propane, which is not a greenhouse gas when released directly into the atmosphere.