Natural gas Natural gas Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium. It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas. Natural gas is a fossil fuel used as a source of energy for heating,
Substitute natural gas condition for large scale introduction of renewable biomethane produced through anaerobic digestion (biogas) or gasification and methanation bio-SNG. Substitute natural gas Substitute natural gas (SNG), or synthetic natural gas, is a fuel gas that can be produced from fossil fuels such as lignite coal, oil shale, or from biofuels (when it is named bio-SNG) or from renewable electrical energy. The Great Plains Synfuels Plant injects approximately 4.1 million m/day of SNG from lignite coal into the United States national gas grid. The production process of SNG at the Great Plains plant involves gasification, gas cleaning, shift, and methanation. China is