Basic Information about Landfill Gas | US EPA (2023)


As of March 2023, there are 532 operational LFG energy projects in the United States and 466 landfills that are good candidates for projects.

  • Learn more about current and potential projects.
  • View answers to frequent questions about landfills and LFG energy projects.
  • Learn more about LMOP.

On this page:

  • Methane Emissions from Landfills
  • Collecting and Treating Landfill Gas
  • Landfill Gas Energy Project Types

Landfill gas (LFG) is a natural byproduct of the decomposition of organic material in landfills. LFG is composed of roughly 50 percent methane (the primary component of natural gas), 50 percent 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 over a 100-year period, per the latest Intergovernmental Panel on Climate Change (IPCC) assessment report (AR5).

Learn more about methane emissions in the United States.

Methane Emissions from Landfills

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Municipal solid waste (MSW) landfills are the third-largest source of human-related methane emissions in the United States, accounting for approximately 14.3 percent of these emissions in 2021. The methane emissions from MSW landfills in 2021 were approximately equivalent to the greenhouse gas (GHG) emissions from nearly 23.1 million gasoline-powered passenger vehicles driven for one year or the CO2 emissions from nearly 13.1 million homes’ energy use for one year. At the same time, methane emissions from MSW landfills represent a lost opportunity to capture and use a significant energy resource.

When MSW is first deposited in a landfill, it undergoes an aerobic (with oxygen) decomposition stage when little methane is generated. Then, typically within less than 1 year, anaerobic conditions are established and methane-producing bacteria begin to decompose the waste and generate methane.

Learn about alternative options for managing organic waste.

The following diagram illustrates the changes in typical LFG composition after waste placement. Bacteria decompose landfill waste in four phases. Gas composition changes with each phase and waste in a landfill may be undergoing several phases of decomposition at once. The time after placement scale (total time and phase duration) varies with landfill conditions.

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(Video) Training Notes on Landfill Gas Emissions Model (US EPA LandGEM) (No narration)

Figure adapted from ATSDR 2008. Chapter 2: Landfill Gas Basics. In Landfill Gas Primer - An Overview for Environmental Health Professionals. Figure 2-1, pp. 5-6. (PDF)(12 pp, 2MB)

Learn more in Chapter 1. Landfill Gas Energy Basics of LMOP's LFG Energy Project Development Handbook.

In October 2009, EPA issued a rule (40 CFR Part 98) that requires the reporting of(GHG) emissions from large sources and suppliers in the United States, and is intended to collect accurate and timely emissions data to inform future policy decisions.

  • Learn more about EPA's Greenhouse Gas Reporting Program
  • Learn more about GHG emissions from the waste sector

Annually, EPA issues an inventory report to present the U.S. government's estimates of U.S. human-related GHG emissions and sinks for each year since 1990. Emissions from the waste sector as well as other sectors are presented in this inventory.

  • Review EPA's Inventory of U.S. Greenhouse Gas Emissions and Sinks

Collecting and Treating Landfill Gas

Instead of escaping into the air, LFG can be captured, converted, and used as a renewable energy resource. Using LFG helps to reduce odors and other hazards associated with LFG emissions, and prevents methane from migrating into the atmosphere and contributing to local smog and global climate change. In addition, LFG energy projects generate revenue and create jobs in the community and beyond. Learn more about the benefits of using LFG.

Flowchart of a Basic LFG Collection and Processing System

LFG is extracted from landfills using a series of wells and a blower/flare (or vacuum) system. This system directs the collected gas to a central point where it can be processed and treated depending upon the ultimate use for the gas. From this point, the gas can be flared or beneficially used in an LFG energy project. Click on the flowchart to view more details, including photographs of LFG collection and processing systems.

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Landfill with waste in placeLandfill gas extraction wells and pipingPrimary processing of landfill gas and flareAdditional treatment of landfill gas

— Click on the flowchart to view details —

Landfill Gas Energy Project Types

There are many options available for converting LFG into energy. Different types of LFG energy projects are grouped below into three broad categories – Electricity Generation, Direct Use of Medium-Btu Gas, and Renewable Natural Gas. Descriptions of project technologies are included under each project type. For more information on LFG energy project technology options and the advantages and disadvantages of each, see Chapter 3. Project Technology Options of LMOP’s LFG Energy Project Development Handbook.

Owners of LFG electricity projects may benefit from reviewing LMOP’s Toolkit for Expiring LFG Electricity Power Purchase Agreements to help them evaluate options for either continuing to generate electricity or to switch to another project type.

Electricity Generation

About 68 percent of currently operational LFG energy projects in the United States generate electricity. A variety of technologies, including reciprocating internal combustion engines, turbines, microturbines and fuel cells, can 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 electricity applications because of its relatively low cost, high efficiency and size ranges that complement the gas output of many landfills. Gas turbines are typically used in larger LFG energy projects while microturbines are generally used for smaller LFG volumes and in niche applications.

(Video) How gases and liquids are drained from landfills

Cogeneration, also known as combined heat and power (CHP), projects use LFG to generate both electricity and thermal energy, usually in the form of steam or hot water. Several cogeneration projects using engines or turbines have been installed at industrial, commercial and institutional operations, using engines or turbines. The efficiency gains of capturing the thermal energy in addition to electricity generation can make this project type very attractive.

Direct Use of Medium-Btu Gas

Directly using LFG to offset the use of another fuel (for example, natural gas, coal or fuel oil) occurs in about 16 percent of the currently operational projects. LFG can be used directly in a boiler, dryer, kiln, greenhouse or other thermal application. In these projects, the gas is piped directly to a nearby customer for use in combustion equipment as a replacement or supplementary fuel. Only limited condensate removal and filtration treatment are required, although some modifications of existing combustion equipment might be necessary.

LFG can also be used directly to evaporate leachate. Leachate evaporation using LFG is a good option for landfills where leachate disposal at a water resource recovery facility is unavailable or expensive. LFG is used to evaporate leachate to a more concentrated and more easily discarded effluent volume.

Innovative direct uses of medium-Btu gas include firing pottery and glass-blowing kilns; powering and heating greenhouses; and evaporating waste paint. Current industries using LFG include auto manufacturing, chemical production, food and beverage processing, pharmaceuticals, cement and brick manufacturing, wastewater treatment, consumer electronics and products, paper and steel production, and prisons and hospitals.

Renewable Natural Gas

LFG can be upgraded to renewable natural gas (RNG), a high-Btu gas, through treatment processes by increasing its methane content and, conversely, reducing its CO2, nitrogen and oxygen contents. RNG can be used in place of fossil natural gas, as pipeline-quality gas, compressed natural gas (CNG) or liquefied natural gas (LNG). About 16 percent of currently operating LFG energy projects are creating RNG.

Options for use of RNG include thermal applications, to generate electricity or as fuel for vehicles. The RNG can be used locally at the site where the gas is produced or can be injected into natural gas transmission or distribution pipelines for delivery to another location.

  • Learn more about RNG created from biogas
  • View data for LFG energy projects

A municipal solid waste (MSW) landfill is a discrete area of land or excavation that receives household waste, and may also receive other types of nonhazardous wastes. Collection of LFG typically begins after a portion of a landfill, known as a “cell”, is closed to waste placement.

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(Video) What is landfill gas? A definition of landfill gas (garbage or dump gas)

LFG collection systems can be configured as vertical wells or horizontal trenches. The most common method is drilling vertical wells into the waste mass and connecting the wellheads to lateral piping that transports the gas to a collection header using a blower or vacuum induction system. Horizontal trench systems are useful in areas of active filling. Some landfills use a combination of vertical wells and horizontal collectors. Collection system operators “tune” or adjust the wellfield to improve collection.

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A basic LFG processing skid includes a knock-out drum to remove moisture, blowers to provide a vacuum to “pull” the gas and pressure to convey the gas, and a flare. System operators monitor parameters to maximize system efficiency.

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(Video) EPA Landfill

Using LFG in an energy recovery system usually requires some treatment of the gas to remove excess moisture, particulates and other impurities. The type and extent of treatment depend on site-specific LFG characteristics and the type of energy recovery system. Some end uses, such as pipeline injection or vehicle fuel projects, require additional cleaning and compression of the LFG.

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(Video) Gas Monitoring at Landfills - Why do we monitor? What do we monitor and how?

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What are the basic information about landfill gas? ›

Landfill gas contains many different gases. Methane and carbon dioxide make up 90 to 98% of landfill gas. The remaining 2 to 10% includes nitrogen, oxygen, ammonia, sulfides, hydrogen and various other gases. Landfill gases are produced when bacteria break down organic waste.

What is the composition of landfill gas EPA? ›

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

What 3 processes produce landfill gas? ›

Three processes—bacterial decomposition, volatilization, and chemical reactions—form landfill gas. Bacterial decomposition. Most landfill gas is produced by bacterial decomposition, which occurs when organic waste is broken down by bacteria naturally present in the waste and in the soil used to cover the landfill.

What is the major concern about landfill gas? ›

Potential to Pose an Explosion Hazard

At some landfills, methane can be produced at sufficient quantities to collect in the landfill or nearby structures at explosive levels. Carbon dioxide is not flammable or explosive. Nitrogen dioxide is not flammable or explosive.

How is landfill gas controlled? ›

Landfill gas is collected and vented through a filter of bacterial slime. As long as oxygen is present, bacteria will decompose landfill gas under aerobic conditions, producing carbon dioxide and water. See the example below of odor controls used at a landfill in California.

How is landfill gas processed? ›

Landfill gases are fed into a collection system which consists of a series of wells drilled into a landfill through a plastic piping system to later produce electricity. These gases could cause fire and explosions in some landfills, promoting close monitoring by the California Environmental Protection Agency.

What are the 4 major components of landfill? ›

WHAT IS THE COMPOSITION OF A LANDFILL? There are four critical elements in a secure landfill: a bottom liner, a leachate collection system, a cover, and the natural hydrogeologic setting. The natural setting can be selected to minimize the possibility of wastes escaping to groundwater beneath a landfill.

What is the gas composition of landfill gas? ›

Landfill gas is composed primarily of 50 percent methane and 50 percent carbon dioxide and other gases produced at less than 1 percent. Methane and carbon dioxide are generated through the biological decomposition of waste.

What are the 5 stages of landfill? ›

Generally, it is accepted that landfills undergo at least four phases of decomposition, (1) an initial aerobic phase, (2) an anaerobic acid phase, (3) an initial methanogenic phase, and (4) a stable methanogenic phase (Christensen and Kjeldsen, 1995).

What is the difference between biogas and landfill gas? ›

Biogas is produced naturally by anaerobic bacteria in municipal solid waste landfills and is called landfill gas. Landfill gas with a high methane content can be dangerous to people and the environment because methane is flammable. Methane is also a strong greenhouse gas.

What are the emissions from burning landfill gas? ›

Combusting the LFG also destroys organic compounds, including methane and non-methane organic compounds (NMOCs). During combustion, these organic compounds chemically react with oxygen in the presence of heat, breaking apart to form water vapor, carbon dioxide, and other less volatile compounds.

What is one benefit of landfill gas? ›

Reduce Air Pollution by Offsetting the Use of Non-Renewable Resources. Create Health and Safety Benefits. Benefit the Community and Economy. Reduce Environmental Compliance Costs.

Is landfill gas sustainable? ›

Landfill gas consists primarily of methane and is produced when organic materials in large landfills decompose. Methane is 20 times more potent than carbon dioxide at trapping heat in the atmosphere. Capturing methane and using it as fuel is a more sustainable alternative to burning it as a waste product.

What is the landfill methane rule? ›

In May, the EPA implemented a 2016 Obama-era rule that will extend existing requirements for methane collection systems to 93 additional landfills. It lowers the emissions threshold for when landfills must install gas collection systems. Once in place, the rule will cut landfill methane emissions about 7% nationally.

How efficient is landfill gas collection? ›

Gas collection efficiencies ranged between 13 and 86% with an average of 50% – a value lower than for Swedish (58%), UK (64%) and US (63%) landfills.

Is landfill gas bad for the environment? ›

Environmental Impact of Landfills

Along with methane, landfills also produce carbon dioxide and water vapor, and trace amounts of oxygen, nitrogen, hydrogen, and non methane organic compounds. These gases can also contribute to climate change and create smog if left uncontrolled.

What are the two basic types of landfills? ›

Municipal Solid Waste Landfills (MSWLFs) – Specifically designed to receive household waste, as well as other types of nonhazardous wastes. Bioreactor Landfills – A type of MSWLF that operates to rapidly transform and degrade organic waste.

What are the three types of landfills? ›

There are 3 main categories of landfills: Municipal Solid Waste Landfills (MSWLFs), Industrial Waste Landfills, and Hazardous Waste landfills. MSWLFs were created to dispose of household waste and other types of nonhazardous waste. Bioreactor landfills are a subcategory of MSWLFs.

What are the 3 most common environmental concerns with landfills? ›

There are three main reasons that landfills are bad for the environment: toxins, leachate, and greenhouse gases. First of all, many materials in the landfill contain toxic substances.

What are the 3 R's of waste management? ›

Waste minimization can be achieved in an efficient way by focusing primarily on the first of the 3Rs, "reduce," followed by "reuse" and then "recycle."

What makes a landfill different than a dump? ›

Dumps allowed leachate to soak into the ground and contaminate the groundwater. Landfill liners prevent leachate from passing into groundwater. Modern landfills have leachate collection systems and the leachate is transported to treatment plants where clean water is produced and pollutants are removed.

What are the four R's of waste reduction? ›

The four Rs - Rethink, Reuse, Reduce, Recycle - are a lifestyle for a sustainable future. ways to reuse items whenever possible; reduce consumption to reduce waste. Purchase only items that can be recycled.

What is the largest landfill gas? ›

Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Trace amounts of other volatile organic compounds (VOCs) comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.

What type of energy is landfill gas? ›

Landfill gas is a type of biomass energy categorized as "waste energy." The process of decomposition—when organic material is broken down by microorganisms—generates methane gas, a greenhouse gas that can be hazardous.

Is landfill gas heavier than air? ›

Because of its explosive potential, methane is the primary concern at landfills. Methane is lighter than air and tends to migrate upwards and escape to the atmosphere.

How can we solve the problem of landfills? ›

What are some solutions to reduce waste in landfills?
  1. Donate clothes-donate clothes to people in need, shelters, or thrift stores.
  2. Reduce food waste-donate unused items for your pantry; save leftovers for the next meal.
  3. Buy things with less packaging or in bulk.
  4. Eliminate plastic bottle use-use reusable drinking containers.
May 10, 2021

How long do things stay in a landfill? ›

But once it's in the landfill, it will take a really long time to decompose! How long? Between 450 and 600 years.

What is landfill gas also known as? ›

Methane is a flammable toxic greenhouse gas twenty times more damaging to the climate than carbon dioxide. Instead of going into the atmosphere and becoming a greenhouse gas which is harmful to the environment, it can be collected in every landfill and used to produce renewable energy.

Is landfill gas a biofuel? ›

RNG derived from LFG is considered a cellulosic biofuel eligible for D3 Renewable Identification Number (RIN) credits under EPA's Renewable Fuel Standard (RFS).

Is landfill gas a good source of energy? ›

Landfill gas is a safe and renewable energy source. Using landfill gas reduces the need to use more polluting forms of energy. Using landfill gas reduces health and community risks, such as air pollution.

Which fuel source is considered the most pollution when burned? ›

These are not just the emissions from the burning of fuels, but also from the mining, transportation and maintenance over a power plant's lifetime. Coal, again, is the dirtiest fuel. It emits much more greenhouse gases than other sources – hundreds of times more than nuclear, solar, and wind.

How can we reduce methane in landfills? ›

Diverting organic waste through incentives and educational awareness. Policies can incentivize organic waste diversion through source separation of organic materials, large-scale deployment of organics recovery technologies, and development of organics processing infrastructure.

Is landfill gas clean? ›

Landfill methane can be tapped, captured, and used as a fairly clean energy source for generating electricity or heat, rather than leaking into the air or being dispersed as waste. The climate benefit is twofold: prevent landfill emissions and displace coal, oil, or natural gas that might otherwise be used.

How much energy does landfill gas generate? ›

Typically, one million tons of landfill waste emit approximately 432,000 cubic feet of LFG per day, enough to produce either 0.78 MW of electricity or 216 MMBtu of heat.

How much energy is in landfill gas? ›

With a heating value of about 500 British thermal units (Btu) per standard cubic foot, LFG is a good source of useful energy, normally through the operation of engines or turbines.

How much worse is methane than co2? ›

Methane is more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere. Over the last two centuries, methane concentrations in the atmosphere have more than doubled, largely due to human-related activities.

Does human waste produce methane gas? ›

Much of the 25% to 45% that remains consists of gaseous methane—produced by bacterial breakdown—and a solid residue which, if dried and concentrated, has an energy content similar to that of coal.

What is the largest source of greenhouse gases? ›

The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels for electricity, heat, and transportation.

What is landfill gas used for? ›

Landfill gas utilization is a process of gathering, processing, and treating the methane or another gas emitted from decomposing garbage to produce electricity, heat, fuels, and various chemical compounds. After fossil fuel and agriculture, landfill gas is the third largest human generated source of methane.

What are the advantages of landfill gas? ›

Landfill gas is a safe and renewable energy source. Using landfill gas reduces the need to use more polluting forms of energy. Using landfill gas reduces health and community risks, such as air pollution. Landfills that use their landfill gas tend to be better managed and make better neighbors.

Why is landfill gas bad for the environment? ›

Environmental Impact of Landfills

Along with methane, landfills also produce carbon dioxide and water vapor, and trace amounts of oxygen, nitrogen, hydrogen, and non methane organic compounds. These gases can also contribute to climate change and create smog if left uncontrolled.

What are the cons of landfill gas energy? ›

Waste-to-energy cons

They include the pollution and particulates it generates, the destruction of useful materials, and the potential to disincentivize more sustainable waste management solutions and renewable energy sources.

What are 3 disadvantages of a landfill? ›

These include:
  • Soil, groundwater and air pollution. As a breeding ground for bacteria and other contaminants, landfills can allow pollution to contaminate the land, sea and air. ...
  • Deforestation. ...
  • Cosmetic impacts. ...
  • Hazardous waste. ...
  • Ecological imbalance.

How is landfill gas converted to electricity? ›

When it comes to converting landfill gas to electricity, the combustion engine is one of the major components to the process. Otherwise known as a biogas generator, a combustion ene does all the hard work when it comes to converting landfill gas to electricity.

What is the most harmful gas to the environment? ›

Carbon dioxide is widely reported as the most important anthropogenic greenhouse gas because it currently accounts for the greatest portion of the warming associated with human activities.


1. Landfill Methane Estimation, Measurement, and Monitoring
(SCS Engineers, Long Beach)
2. Green Power: Landfill Gas Collection & Utilization Project
(Town of Oakville)
3. Landfill Gas to Energy
(Dave & Darlene Duprey)
4. Landfill Gas Generation and Management
(Geoenvironmental Engineering Webinars)
5. How Does a Modern Landfill Work?
6. Generation and Control of Landfill Gas
(Geoenvironmental Engineering)


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