What is biogas?
Biogas is produced by fermentation or gasification of organic (residual) material, such as manure, sewage sludge and cutting residues from agricultural crops such as corn and sugar beet. But also wood chips, used cooking oil and algae and seaweed can be used. Putting this biomass in a heated, airtight tank creates the perfect conditions for the bacteria that naturally occur in the material to convert carbon (the material’s main ingredient) into biogas.
This biogas mainly consists of methane and carbon dioxide, but also contains sulfur and moisture. The latter two must be removed from the biogas to be able to burn the gas in a special biogas installation. In the Netherlands there are dozens of farms that have established their own energy cycle in this way: manure or other organic material enters the biogas plant and biogas and electricity come out. Biogas is also used for heating swimming pools and in industry.
It is also technically possible to heat residential houses with biogas. A special 'multi-gas boiler' for this was developed years ago, but interest in this was low and the boiler has not yet been put into production. Currently, in the Netherlands biogas is mainly used to generate green electricity in combined heat and power plants and as ‘green gas’ (biogas converted into natural gas) for car fuel and to feed into the natural gas network.