Natural gas is a mixture of light hydrocarbons that are gaseous at atmospheric conditions. It is normally composed of 85% methane (CH4), 10% ethane (C2H6), 3%, propane (C3H8), butane (C4H10) and some condensates. Natural gas is the product of the decay of organic matter and it can be found in underground reservoirs, either alone or together with crude oil and salt water.
It is used in the industrial sector as process fuel, and in the residential and commercial sectors as fuel for heating and hot water.