landfill gas (LFG)

Gas created by the action of microorganisms within a landfill. [...] Landfill gas production results from chemical reactions and microbes acting upon the waste as the putrescible materials begins to break down[1] in the landfill. The rate of production is affected by waste composition and landfill geometry, which in turn influence the bacterial populations within it, chemical make-up, thermal characteristics, entry of moisture and escape of gas. [...] Some environmental groups claim that [LFG to energy] projects do not produce renewable power because trash (their source) is not renewable. Source: Wikipedia