Natural gas is a combination of lighter hydrocarbons, in particular methane, propane, and butane. It is found either in association with oil deposits or on its own. The sulphur in natural gas can be separated before the has is used as a fuel.
Natural gas is odorless, shapeless, and colourless in its pure form.
The price of natural gas varies greatly depending on its location and type of consumer, but as of 2006 the price of 10 dollar per 1000 cubic feet.
The major difficulty in the use of natural gas is transportation and storage because of its low density
Natural gas makes up about 21 percent of the total energy used world wide.