Methane from Landfills Methane is a hydrocarbon gas (CH4). It is a greenhouse gas and it is explosive. Methane is generated by decomposition (in landfills, swamps, in the stomachs of cows, etc.) and is considered a biomass energy fuel. In this discussion we will focus on methane from landfills. Natural gas is approximately 80-99% The post Methane from Landfills appeared first on Energy Forums.