Hydrocarbons, such as natural gas and crude oil, are formed from the decay of plants and minerals which have been buried for millions of years. They are found in porous rock formations in which the gas or oil is stored in the spaces between the rock particles, like the pores in a sponge. Because the rocks may be at great depths, the gas or oil will be under pressure and will flow to the surface when the pressure is released, for example by drilling a well.Natural gas is generally composed of methane and other gases, such as ethane or propane. The natural gas produced from Humbly Grove consists mainly of methane and requires processing, including separation of water and liquid hydrocarbons, before piping to the natural gas grid.
Gas has been used as a domestic fuel for many years and is now also widely used for power generation, with many new highly efficient gas-fired power stations being built to replace older coal burning stations. These new units are known as “combined-cycle” stations, because, in addition to burning gas to drive electricity-generating turbines, they also make use of the hot exhaust gases to generate steam which can be used to generate additional electricity.
Gas is now widely distributed by a pipeline network throughout Western Europe and the gas used by consumers in the United Kingdom may come from a variety of sources, including Norway, Europe and the North Sea. Technology also allows gas to be transported by ship, as it may be liquefied by cooling to very low temperatures – this is known as Liquefied Natural Gas (LNG).