Biogas

Biogas is a renewable gaseous fuel generated from organic materials including agricultural residues, manure, municipal waste, plant matter, sewage, wastewater, green waste, and food waste. Biogas is produced industrially via anaerobic digestion with anaerobic organisms or methanogens inside an anaerobic digester or other type of bioreactor. The gas composition is primarily methane (CH4) and carbon dioxide (CO2) with small amounts of hydrogen sulfide (H2S) produced as a byproduct. Biogas is typically saturated with water vapour as a result of anaerobic micro-organisms living in water. Trace quantities of volatile organic compounds and siloxanes can also vapourize into biogas, if they are present in the biomass feedstock. Biogas is considered to be a renewable energy resource as the methane can be combusted to release energy. This energy release allows biogas to be used as a fuel. Biogas and its derivatives are used for multiple purposes including heat for cooking, electricity generation, and as a vehicle fuel. At a high level, biogas is a carbon-neutral fuel in so far as emissions of carbon dioxide from its combustion are matched by carbon dioxide pulled from the atmosphere to produce biomass. In practice, the carbon intensity of biogas can vary depending on emissions from the production of biomass and the processes used to produce and upgrade biogas. In some applications, the capturing of biogas can avoid emissions of methane reducing overall emissions. Biogas can be upgraded to natural gas quality specifications by stripping carbon dioxide and other contaminants. Biogas that has been upgraded to interchangeability with natural gas is called renewable natural gas (RNG). RNG can be used as a drop-in fuel in the gas grid or to produce compressed natural gas as a vehicle fuel.