Waste-to-energy

Landfill Gas

FAQ

Q1.	Can landfill gas be considered a renewable energy source?
Ans:	Yes. Landfill gas is generated by the decay of organic materials, the latter being a form of biomass. As biomass contains stored energy derived from solar radiation through photosynthesis, landfill gas can be considered a renewable energy source.

Q2.	For how long will landfill gas be produced at a landfill?
Ans:	The production of landfill gas depends on a number of factors such as waste characteristics (e.g. types and ages of wastes buried in the landfill) and environmental factors such as temperature, moisture, and oxygen availability in the landfill. Generally, landfill gas can be produced at a landfill for over 30 years.

Q3.	Why is it necessary to install gas collection system to collect landfill gas, but then flare off the surplus gas?
Ans:	Landfill gas may migrate through underground paths to outside the landfill. Gas collection system installed can reduce the amount of gas that may escape from the landfill through such paths. Landfill gas can form an explosive mixture with air, when mixed with air in certain proportions. Flaring off the surplus gas (i.e. burning the surplus gas) will reduce the risk of accumulation of landfill gas to an explosive proportion. Furthermore, methane (a major constituent of landfill gas) is a greenhouse gas with a global warming potential over 100 years of 23, meaning that when averaged over 100 years each kg of methane warms the Earth 23 times as much as the same mass of carbon dioxide. Therefore, destruction of methane by flaring would help to reduce the global warming effect caused by landfill gas.