Landfill Gas (LFG)

Landfill Gas (LFG) is a natural byproduct from the decomposition of organic material in landfills. LFG is composed of roughly 50% methane (the primary component of natural gas), 50% carbon dioxide (CO2) and a small amount of non-methane organic compounds. 

Methane is a potent greenhouse gas, at least 28 times more effective than CO2 at trapping heat in the atmosphere, per the latest Intergovernmental Panel on Climate Change (IPCC) assessment report (AR5). 

When Municipal Solid Waste (MSW) is first deposited in landfills, it undergoes an aerobic decomposition stage where minimal methane is generated. Then, typically within less than 1 year, anaerobic conditions are established and the methane producing bacteria begin to decompose the waste, thus generating significant methane emissions. 

Municipal Solid Waste (MSW) landfills are the third largest source of human-related methane emissions throughout 

the United States. 

In 2021 alone, MSW landfills accounted for approximately 14.3% of human-related emissions. These were essentially equivalent to the greenhouse gas (GHG) emissions from:

• 23 million gasoline powered passenger vehicles driven for one year
• CO2 emissions from nearly 13 million homes

At the same time, methane emissions from MSW landfills represent a lost opportunity to capture and use a significant and abundant energy resource. Instead of endlessly escaping and polluting; LFG can be captured, converted, and used as a renewable energy source. 

Utilizing LFG as a renewable energy source will help to reduce odors and other hazards associated with LFG emissions,  prevent methane from migrating into the atmosphere,  contribute to local smog reduction, and aid in global climate change actions. 

The extraction of LFG from landfill consists of a series of wells and a blower/flare (vacuum) system. This system directs the collected gas to a central point where it is then processed and treated, depending upon the ultimate use for the gas. From this point, the gas can be flared or used in an LFG energy project.

Roughly 68% of currently operational LFG-to-Energy projects in the United States generate electricity. These operations showcase a variety of technologies: reciprocating internal combustion engines, turbines, micro-turbines, and fuel cells which can all be used to generate electricity for onsite use and/or sale to the grid. 

The reciprocating engine is the most commonly used conversion technology for LFG-to-Electricity applications due to the low cost, high efficiency, and size ranges. Gas turbines are typically used in larger LFG-to-Energy projects, while micro-turbines are generally used for smaller LFG volumes or

 in niche applications.