The term ‘biogas’ is commonly used to refer to a gas which has been produced by the biological breakdown of organic matter in the absence of oxygen.
What can biogas be used for?
Biogas power generation
Biogas energy can also be used to generate power. Both electricity and heat can be produced with the help of a gas powered generator. The proportions of heat and power generated depend of course on the design of the plant but are usually in the region of 35 per cent electricity and 65 per cent heat.
Biogas as vehicle fuel
Biogas can be utilised in a process called Compressed Natural Gas or CNG. The biogas from an AD plant is compressed to less than 1% of its volume at standard atmospheric pressure. Consisting mostly of methane, CNG is odourless, colourless and tasteless and can be used as an alternative fuel to power vehicles.
Biogas in the gas network
Refined biogas can be injected into existing gas networks. Functioning networks with natural gas are being used for gas cookers, heaters, baking ovens, water heaters in many towns and cities all over the world
Biogas in industry
Many industries such as sugar refineries, distilleries, dairies and paper mills generate processing and waste water which can be used as a source of feed stock for AD plants and digested directly on site. The biogas created can then be used on site for heating premises, district heating, power production and any heat requirements for the site process.
AD is a microbiological process of decomposition of organic matter, in the absence of oxygen, common to many natural environments and largely applied today to produce biogas in airproof reactor tanks, commonly named digesters. A wide range of micro-organisms are involved in the anaerobic process which has two main end products: biogas and digestate. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Digestate is the decomposed substrate, rich in macro- and micro nutrients and therefore suitable to be used as plant fertilizer.