Biogas and Landfill Gas

The potential for energy from biogas using existing sources of organic waste is in the order of 1.4PJ, enough for more than 30,000 homes for a year!

Biogas is a gas produced during the biological breakdown of organic
matter which can be used to provide energy. The gas is produced
from the decay of vegetation and other organic materials such as
animal manures, sewage treatment sludge or food processing
waste. This can occur in places where there is little or no oxygen
such as in a landfill (where it is known as landfill gas) or under
controlled conditions such as an engineered waste digester.

Biogas emitted from landfill sites or engineered waste digesters can be used to provide heat or to generate electricity.

Why use biogas for energy?

Utilising biogas makes sense because it occurs as a result of a number of existing natural processes and the gas would otherwise be emitted into the atmosphere as a harmful greenhouse gas. Biogas contains methane, which has twenty times more greenhouse effect
than carbon dioxide. The process of burning biogas for electricity generation or heat converts the methane into carbon dioxide, therefore significantly reducing the environmental impact.

Using biogas technology also means that the polluting potential of organic material is reduced. For example a farmer may choose to collect the effluent from a shed and convert it into gas in an engineered waste digester. By doing so, the farmer avoids having to dispose of the material in the local river which can harm the environment, incur a disposal charge and possibly contaminate the area if any disease was present in the original waste. The farmer can then use the sludge from the digester as a fertiliser as any harmful bacteria will have been killed during the gasification process.