Work out landfill gas generation instantly with clear inputs, formula shown and shareable results.
First-order decay models express annual methane generation as waste in place times methane potential times the decay constant. Methane potential is 50-170 m3 per tonne depending on organic content, and k ranges from 0.02 per year in arid sites to 0.09 in wet ones. Collection efficiency of 60-85% is achievable with active wells and capping.
First-order decay
Annual methane = waste in place x L0 x k
Energy
Energy = methane x 9.94 kWh/m3; electrical = energy x engine efficiency
Landfill gas is explosive and asphyxiating and its methane emissions are regulated. Gas management systems and monitoring are permit requirements.
Methane has a global warming potential around 28 times carbon dioxide. Even 25% escaping collection makes landfill a major emissions source, which is why gas capture is mandated at most modern sites.
Generation peaks shortly after closure and then declines exponentially. Engine capacity must be planned to be downsized or the gas upgraded or flared as output falls below viable levels.