What is landfill gas?
Landfill gas (LFG) is an alternative energy source that is obtained from waste matter dumped in a landfill. When organic solid waste decomposes in a landfill, the process is accompanied by the release of methane gas. These emissions can be trapped and used as a source of energy. Methane makes up nearly 50% of landfill gas. The other 50% is carbon dioxide. In addition, there are small amounts of non-methane organic compounds (NMOC).
How is landfill gas converted to energy?
Allowing landfill gas to escape into the atmosphere decreases the quality of air and adds to greenhouse gas emissions. Instead, this gas can be collected and converted into energy. The first step in obtaining energy from the gas is to capture it. As the gas is generated in a landfill, it is sucked into wells using a blower or vacuum system. The captured gas is then transported to a central point where it is processed and converted into a usable form.
What are the different forms of use?
Electricity: Most of the landfill gas is used to generate electricity. Electricity generation is accomplished using turbines, internal combustion engines, microturbines, stirling engines, fuel cells, and organic Rankine cycle engines. Turbines and internal combustion engines are the most commonly used electricity generation apparatuses at present.
Thermal energy: LFG can be used as a direct substitute for other energy sources like coal, fossil fuels, natural gas, etc. This is primarily achieved by converting LFG to thermal energy. LFG can be used to power dryers, boilers, kilns, and greenhouses.
Cogeneration: Landfill gas is also capable of running combined heat and power (CHP) systems. The CHP system makes use of LFG to generate both steam for power generation and hot water for heating systems. Using a CHP system provides high energy efficiency.
What are the benefits of using landfill gas?
Using landfill gas is not only an energy efficient option but also an environmentally sound one. Methane is one of the primary constituents of greenhouse gases and landfills are among the largest methane generators. LFG can account for up to 90% of methane generated in a landfill.
LFG is an alternative to traditional, exhaustible fuel sources. Using LFG instead of fossil fuels produces lesser amounts of harmful emissions that pollute the air. Air quality is further improved due to the reduced presence of odor-producing methane gas.
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