What is Biogas?
Biogas typically refers to a gas produced by the breakdown of organic matter in the absence of oxygen. It is a renewable energy source, like solar and wind energy. Furthermore, biogas can be produced from regionally available raw materials and recycled waste and is environmentally friendly. Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials such as manure, sewage, municipal waste, green waste, plant material, and crops.
Biogas comprises primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S) and moisture. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel. Biogas can be used as a fuel for any heating purpose, such as cooking. It can also be used in a CHP (Combined heat and power) engine, which is driven by BioGas to produce electricity and useable heat. Biogas can be compressed, much like natural gas, and used to power motor vehicles. Biogas can also be cleaned and upgraded to natural gas standards when it becomes bio methane.
The most common method of producing BioGas (as explained above) is by fermenting organic waste in an anaerobic digester. In practice this translates into a tank kept at constant temperature which house the waste while bacteria of different types digester the solids and produce gas. In order to explain the process in which BioGas is produced it is easier to use the analogy of a stomach.
By eating and drinking we load our stomachs (digesters) with waste. The good bacteria in our stomachs break down the solids (in the absence of oxygen) and produce a solid, a liquid and a gas.
A digester on the other hand expels an extremely nutrient solid compost, liquid fertilizer and of course BioGas!
*Diagram Provided by Farmatic Solutions*
There are a large variety of feedstocks that are suitable for digestion. As a general rule, if it grows from the earth it is organic, and anything organic can be digested. As always there are exceptions, wood is probably the most common one. However, for the waste’s that can’t be digested to produce BioGas we have other processes that can use them to produce energy. There’s no harm in asking us!