Biogas is a gas produced through biomethanisation, a process in which organic matter is decomposed in the absence of oxygen.
Biogas consists mainly of methane (50-80% CH4) and carbon dioxide (20-40% CO2). Other gases are present in small quantities: dihydrogen (H2), hydrogen sulphide (H2S), dinitrogen (N2) and steam (H2O). The energy content of the biogas comes from methane and dihydrogen.
> Production of heat or steam by combustion of biogas in a boiler;
> Production of electricity by combustion in an engine or turbine;
> Production of both electricity and heat also called cogeneration. This is the most current biogas recovery in Europe.
Biogas can also be cleaned to keep the biomethane fraction and compressed to produce biofuel or be injected into the natural gas network.
In most cases, it is necessary to purify the biogas prior to use. It is recommended, whatever the recovery system is, to remove the water and hydrogen sulphide in order to not damage equipment.
Biogas, a sustainable gas
Through the use of feedstocks such as livestock manure or agricultural and agro-food waste, biomethanisation helps to avoid emissions of methane that would otherwise be released into the atmosphere (generating pollution) without any energy recovery.