CNG & LPG are physical conversions of natural gas for transport and storage purposes.
CNG stands for compressed natural gas, and is a method of taking natural gas from the ground and compressing it to make it more easily transported and space-efficient. LPG stands for liquefied petroleum gas. LPG production occurs in the refining process of crude oil. Common names for LPG are butane and propane.
Natural gas is not cost-effective in its natural form for shipping and storage so different methods were developed to store and transport natural gas.
These are not to be confused with LNG, or liquefied natural gas. LNG & CNG are both natural gas just converted to different forms.
LNG is very expensive to create so it is used mostly in large production companies. Natural gas from the ground without any processing is 600 times more voluminous than LNG. This difference makes LNG a very valuable conversion in large quantities for export.
Compressed natural gas is primarily composed of methane. It has relatively low flammability, is lighter than air and is nontoxic to land, water or air exposure. These attributes make it useful as an alternative to gasoline. While it has yet to catch much of a hold in the United States’ automobile industry, it is widely used overseas. And in fact, CNG-fueled vehicles were used as far back as WWII. CNG is 50% cheaper than gasoline and emits far fewer emissions than gasoline.
Liquefied petroleum gas is a mix of hydrocarbon gases in liquid form. The two common names for LPG are butane and propane. They differ slightly in their chemical makeup. They are used in refrigerators, cigarette lighters, portable heating sources and as a propellant in many other domestic and commercial fashions. When combined in a very specific way, they produce something known as Autogas. Autogas is a petrol (gasoline) alternative used primarily in Europe.