Landfill methane comes from bacteria breaking down garbage in landfill sites. Besides being a greenhouse gas, methane creates odours and can migrate underground, collect inside buildings and cause explosions. In extreme cases, it can ignite and cause large, highly polluting fires that are difficult to extinguish. For these reasons, most municipalities are required to collect and destroy the methane.
Landfill operators collect methane by building a system of wells and pipes that convey the gas to a header. Traditionally landfills would burn, or ‘flare,’ the methane they collect. Today, this is recognized as wasting a valuable resource. Alternatively, landfill-gas-to-energy projects use gaseous-fueled generators, to produce electricity and/or thermal energy. Since landfills require very little electric energy, electricity can be sold back to the grid.
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