The landfill deposition of organic materials such as food waste, yard trimmings, paper and wood results in the generation of landfill gas. Anaerobic bacteria degrade these materials to produce landfill gas, which primarily contains methane and carbon dioxide. Landfill gas is typically a combination of methane (50-55%), carbon dioxide (45-50%) and non-methane organic compounds. In addition, oxygen and nitrogen are also observed in landfill gas, which are present mainly as a result of air infiltration.
Landfill gas can be used as a fuel in internal combustion engines or combustion turbines driving either an electrical or gas-powered generator. The generated electricity can be used to power on-site needs such as the blowers for the active gas collection system or leachate treatment system or, more typically, be sold to the local electricity grid. Electricity generation from landfill gas accounts for the majority of landfill gas to energy projects globally.