Biogas typically refers to a mixture of different gases produced by the decomposition of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, vegetable matter, sewage, green waste or food waste. It is a renewable energy source, and in many cases, uses a very small carbon footprint.

The biogas can be produced from the anaerobic digestion by anaerobic bacteria which digest materials within a closed system, or fermentation of biodegradable materials.

Biogas is mainly methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes. The methane gas,hydrogen and carbon monoxide (CO) can be combusted or oxidized with oxygen.

This energy release allows biogas to be used as fuel • can be utilized for purposes of heating, such as cooking. It can also be used in a gas engine to convert the energy in the gas to electricity and heat.

Biogas can be compressed in the same manner compressed gas into compressed gas and used to supply power to vehicle engines. In the UK, for example, biogas is estimated to have the potential to replace about 17% of vehicle fuel.

Certified as renewable energy substitute in some areas of the world. Biogas can be cleaned and upgraded to natural gas standards when it becomes biomethane.

The composition of biogas varies depending on the origin of the raw material anaerobic digestion. The landfill gas is methane concentrations usually around 50%.

Advanced waste treatment technologies can produce biogas with 55% -75% methane, that for reactors of free liquid can be increased to 80% -90% methane, using site gas purification techniques.

As produced, biogas contains water vapor. The fractional volume of water vapor is a function of the temperature of biogas • the correction of the measured volume of gas for the content of water vapor and the thermal expansion is made easy by simple mathematics, giving the standard volume of dry biogas.

Biogas can be used to generate electricity in sewage works, in a gas engine cogeneration (CHP), wherein the waste heat from the engine used comfortably for: heating the digester, cooking, space heating, water heating and heating processes.

If compressed biogas can replace compressed natural gas for use in vehicles, which can power internal combustion engines or fuel cells, replacing much more effective carbon dioxide from normal use on-site CHP plants