Natural gas is a colourless, odourless gas that is easy to burn and typically consists mostly (90% or more) of methane (CH4). Unprocessed natural gas, also called raw natural gas, is one of the main primary energy sources in the world, making up roughly 1/5 of the world’s primary energy. After processing, most people still referred to the substance as natural gas, but this end use natural gas is sometimes referred to as consumer natural gas also referred to as sales gas or marketable gas. Consumer natural gas is a flexible energy currency and 15% of the world’s end use energy comes from consumers burning natural gas in their homes or businesses. This is in addition the natural gas that gets turned into electricity.

In its unprocessed state, raw natural gas is composed of varying quantities of methane, ethane, propane, butanes, and pentanes. Often impurities such as oxygen, hydrogen sulfide, nitrogen, water and carbon dioxide are also present. Once natural gas has been processed for consumption, consumer natural gas is primarily methane with trace amounts of other molecules.

Like all fossil fuels, natural gas formed from the decomposing remains of animals and plants that lived millions of years ago. The high pressure and temperatures present deep underground facilitated the conversion of plant and animal matter to hydrocarbon fuels.