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AgSTAR

AgSTAR Data and Trends

In the United States, there are 273 manure-based anaerobic digestion systems operating in the United States and helping to reduce greenhouse gas emissions from methane. Of these, 108 systems have been awarded grants by the United States Department of Agriculture. This page provides national market data and trends related to these biogas recovery systems.

You can also find information on individual anaerobic digesters operating on livestock farms in the United States, including:


Anaerobic Digestion Potential for Livestock Farms in the United States

AgSTAR estimates that biogas recovery systems are technically feasible for over 8,000 large dairy and hog operations. These farms could potentially generate nearly 16 million megawatt-hours (MWh) of energy per year and displace about 2,010 megawatts (MWs) of fossil fuel-fired generation.

Use of anaerobic digestion for poultry and beef operations is growing as new technologies enter the market. Although these systems are technically feasible, their economic feasibility can vary.

Market Opportunities for Biogas Recovery Systems at U.S. Livestock FacilitiesMarket Opportunities for Biogas Recovery Systems at U.S. Livestock Facilities assesses the market potential for biogas energy systems for dairy and hog farms in the United States.

Challenges and Opportunities for California's Dairy Economy​Challenges and Opportunities for California’s Dairy Economy Exit explores the potential of dairy biogas systems to reduce environmental impacts while generating energy and/or income for dairies.

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Anaerobic Digester Facts and Trends

The chart below shows the growth in the number of cumulative operating digester systems accepting livestock manure (Source: AgSTAR Livestock Anaerobic Digester Database). In addition to the 17 systems that came online in 2020, another 60 are currently under construction.

 

Year Operational1 Newly Operational2 Shut Down
2021 273 0 0
2020 273 17 0
2019 257 14 3
2018 246 10 2
2017 238 9 4
2016 233 4 9
2015 238 8 5
2014 235 9 5
2013 233 30 2
2012 205 31 1
2011 175 25 9
2010 159 18 3
2009 141 24 15
2008 132 33 7
2007 106 18 3
2006 91 21 2
2005 72 15 2
2004 59 18 2
2003 44 7 1
2002 39 10 1
2001 31 6 0
2000 25 1 1

1 Data provided in the table for Operational digester projects are inclusive of Newly Operational digester projects.
2 Newly Operational digester projects are projects that began processing feedstock in the corresponding calendar year.

There are a number of different types of anaerobic digestion systems. Complete mix and mixed plug flow designs are currently used in the majority of anaerobic digestion systems that accept livestock manure.

 

System Type Count
Plug Flow* 100
Complete Mix 87
Covered Lagoon 71
Induced Blanket Reactor 5
Anaerobic Sequencing Batch Reactor 3
Fixed Film 2
Dry Digester 1
Other/Unknown 4

Learn more about the type of anaerobic digesters being used for livestock manure:

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Biogas Facts and Trends

Captured and recovered biogas can be used to generate electricity, to fuel boilers or furnaces, or to create pipeline quality gas or compressed natural gas that can be sold as a vehicle fuel. While a variety of biogas use options are available, collected biogas is most often used to generate electricity and provide combined heat and power (CHP). CHP projects generate electricity and use the excess heat from electricity generation to heat digesters or adjacent buildings.

The line chart below shows trends in the end uses of biogas from manure-based anaerobic digestion systems since 2000. CHP is the most common end use, followed by electricity.

  • The number of CHP projects steadily increased each year from 2000 to 2015, and then began to slightly decline.
  • The number of electricity projects steadily increased each year from 2000 to 2013. Since then, the electricity project count has become more stable.
  • The number of boiler and furnace fuel projects increased much more slowly from 2000 to 2013 and has seen little change since.
  • Renewable natural gas (RNG) projects, including pipeline injection and compressed natural gas (CNG) for vehicle fuel or other uses, have risen steadily and significantly since 2017.
  • Projects that flare the biogas full time currently make up approximately 4 percent of all projects.
 

Year Combined Heat and Power Electricity Boiler/Furnace Fuel Flared Full Time CNG Pipeline Unknown
2021 121 85 13 12 36 16 1
2020 121 85 13 12 36 16 1
2019 124 86 13 13 22 8 1
2018 125 83 13 13 11 4 1
2017 125 82 13 13 4 3 1
2016 126 78 13 13 4 1 1
2015 128 79 13 13 5 1 3
2014 124 79 13 14 5 0 4
2013 121 83 12 12 6 0 4
2012 106 70 12 12 5 1 3
2011 94 53 11 14 4 1 1
2010 86 45 13 14 6 1 0
2009 77 37 11 14 3 2 0
2008 73 34 11 10 3 4 0
2007 66 22 11 5 1 1 1
2006 51 22 11 5 0 1 1
2005 37 21 9 3 1 1 1
2004 28 19 8 2 0 1 1
2003 21 13 7 2 0 0 1
2002 18 10 8 2 0 0 1
2001 13 9 6 2 0 0 1
2000 11 7 4 2 0 0 1

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Environmental Benefits

  • In calendar year 2020, manure-based anaerobic digesters reduced GHG emissions by 5.00 million metric tons of CO2 equivalent (MMTCO2e).
    • 4.17 MMTCO2e direct methane reductions
    • 0.82 MMTCO2e emissions avoided
  • From 2000 through 2020, manure-based anaerobic digesters have reduced direct and indirect emissions by 46.6 MMTCO2e.
  • In 2020, energy generation from manure-based anaerobic digesters was approximately 1.46 million megawatt-hours (MWh) equivalent.

The chart below shows the amount of direct and indirect GHG emission reductions from manure-based anaerobic digesters since 2000. The chart shows a steady increase through 2013 with a total of 5.00 MMTCO2e in 2020. The increase in direct reductions in recent years is driven in large part by the uptick in RNG projects coming online since 2017.

 

Year Direct Reductions (MMTCO2e) Indirect Reductions (MMTCO2e)
2020 4.17 0.82
2019 3.79 0.80
2018 3.20 0.73
2017 2.89 0.72
2016 2.85 0.75
2015 2.78 0.77
2014 2.94 0.76
2013 2.90 0.73
2012 2.30 0.59
2011 1.88 0.44
2010 1.66 0.38
2009 1.48 0.31
2008 1.37 0.27
2007 0.94 0.16
2006 0.85 0.12
2005 0.61 0.08
2004 0.45 0.06
2003 0.32 0.05
2002 0.28 0.04
2001 0.23 0.03
2000 0.10 0.01

The following chart shows energy generation from electricity projects and non-electricity projects since 2000. The chart shows a gradual increase from 2000 through 2007 and then a more significant increase from 2008 through 2013. Energy generation has increased significantly over the last few years, due in large part to the RNG projects coming online since 2017. In 2020, manure-based anaerobic digestion systems generated the equivalent of approximately 1.46 million MWh of electricity.

 

Year Electricity Projects (Million kWh/yr) Non-Electricity Projects (Million kWh/yr Equivalent)
2020 1012.2 445.0
2019 1002.2 349.4
2018 979.1 71.5
2017 942.1 39.1
2016 942.2 19.3
2015 958.9 3.7
2014 974.1 3.7
2013 939.2 3.7
2012 714.3 57.2
2011 500.9 56.9
2010 432.8 57.3
2009 343.8 81.3
2008 286.5 97.6
2007 154.3 19.5
2006 117.9 19.5
2005 75.1 17.3
2004 64.0 17.3
2003 44.5 0.7
2002 31.1 0.2
2001 20.9 0.2
2000 17.6 0.2

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Value of Anaerobic Digester Biogas and Coproducts

The Innovation Center for U.S. Dairy Exit provides information about production possibilities and market values of the products from anaerobic digesters.

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State Data and Trends

State Data Sources

Renewable Portfolio Standards

A state renewable portfolio standard (RPS) encourages or requires utilities to use or buy renewable energy or renewable energy certificates (RECs) to account for a certain portion of their retail electricity sales by a certain date. A REC is a tradable certificate documenting that 1 megawatt-hour of renewable electricity was generated at a specific facility. The goal of an RPS is to stimulate market and technology development so that renewable energy can become more competitive with conventional forms of electric power. A state RPS helps create market demand for renewable energy.

Generally, electricity suppliers can meet the RPS targets by:

  • Owning a renewable energy facility and its output generation.
  • Purchasing RECs.
  • Purchasing electricity from a renewable facility.

Biogas from anaerobic digesters often qualifies as renewable energy under the biomass category of state RPS systems.

Additional information on states with RPS targets is available from the following sources:

Feed-in Tariffs

  • Feed-in tariffs (FIT) Exit are a policy tool used to encourage renewable electricity technologies. A FIT program typically guarantees that customers who own a FIT-eligible renewable electricity generation facility will receive a set price from their utility for all of the electricity they generate and provide to the grid.

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Year Under Construction Newly Operational Operational Shut Down
2021 60 0 273 0
2020 0 17 256 0
2019 0 14 243 -3
2018 0 10 236 -2
2017 0 9 229 -4
2016 0 4 229 -9
2015 0 8 230 -5
2014 0 9 226 -5
2013 0 30 203 -2
2012 0 31 174 -1
2011 0 25 150 -9
2010 0 18 141 -3
2009 0 24 117 -15
2008 0 33 99 -7
2007 0 18 88 -3
2006 0 21 70 -2
2005 0 15 57 -2
2004 0 18 41 -2
2003 0 7 37 -1
2002 0 10 29 -1
2001 0 6 25 0
2000 0 1 24 1