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SWICS Landfill Emissions Model

Technologies that can directly and accurately measure total methane emissions from large areas such as landfills are still being developed, therefore operators must rely on models to estimate total methane emissions. Robust models are essential for tracking the quantity of methane released from landfills and to understand how operational changes affect emissions.

About the Landfill Emissions Model 

Engineered landfills are complex environments and the dynamics of landfill gas (LFG) carbon accounting are intricate tying together landfill gas generation, collection and destruction efficiencies, methane oxidation through cover material, and carbon sequestration. The Landfill Emissions Model (LEM) brings together these components to calculate the emissions of a landfill.  

The model produces a summary of methane emissions, biogenic carbon dioxide emissions, sequestered carbon, and gas sent for beneficial use. It also generates a calculated collection efficiency based on the attributes of each landfill’s operations. The LEM uses the Landfill Gas Collection System Efficiency Scoring Matrix to calculate a gas collection efficiency using site-specific properties. 

These results are based on the following inputs:

Landfill Gas:

Gas composition, flow rate and destruction efficiency of destruction devices, surface emissions monitoring activity and exceedances

Site Characteristics:

Area with each cover type, density and location of collectors, average rainfall, moisture content of waste, uptime of LFG collection system 

Site History:

Years active, waste placement and composition

Since its development, the Solid Waste Industry for Climate Solutions (SWICS) group has continued to improve the model by updating model parameters in accordance with scientific and industry norms  and making the variables in the model  more objective. Additionally, by testing data from over 300 landfills in the LEM, SWICS is identifying best practices and setting industry benchmarks.

Using the Landfill Emissions Model 

The LEM is used by several landfill operators in their Environmental, Social and Governance reporting.

Want to explore the model on your own? Access the User Guide, Model, and accompanying report: 

DOWNLOAD THE MODEL

If you need assistance accessing the LEM, please fill out the contact form below:

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History of the LEM 

In July 2007, SWICS released its first guidance document titled Current MSW Industry Position and State-of-the-Practice on LFG Collection Efficiency, Methane Oxidation, and Carbon Sequestration in Landfills. In the 2007 document, SWICS proposed a revision to the existing California Air Resources Board (CARB) methodology for calculating methane emissions from landfills. The intent of SWICS was to create a methodology that would result in more accurate inventories of methane emissions from landfills. The 2007 document was updated in 2009, and the methane oxidation methodology was further updated in 2012. The model parameters related to gas collection efficiency were updated in 2023 to eliminate subjectivity. 

Version 2.3 is currently undergoing a two-pronged academic review: (1) The model parameters are being reviewed to ensure they reflect current scientific literature. (2) The Landfill Gas Collection System Efficiency Scoring Matrix is being validated and will be updated as appropriate.