Natural gas: five questions and answers

Andrew Hopkins

1. What exactly is natural gas?

Natural gas, along with oil and coal, is a combustible organic raw material. It is a mixture of approximately 85 percent methane plus around ten percent nitrogen dioxide and carbon dioxide. The remainder is made up of higher hydrocarbons such as ethane, propane and butane. Natural gas is available as two types: Compressed Natural Gas (CNG), which broadly maintains its natural state, and Liquefied Natural Gas (LNG), which becomes a liquid when cooled to -164 degrees Celsius. The great advantage of LNG is its significantly higher energy density per volume as, in a liquefied state, it is reduced to 1/600th of its initial volume. However, CNG is the more common, since compressed gas is currently easier to handle than gas in the form of an extremely cold liquid. Natural gas should not be confused with Liquefied Petroleum Gas (LPG) which retails under the name of Autogas.