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AgSTAR

AgSTAR Data and Trends

There are 255 anaerobic digester projects operating on livestock farms in the United States, helping to reduce greenhouse gas emissions from methane.  Of these, 107  projects 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:


Potential for Anaerobic Digestion on Livestock Farms in the United States

AgSTAR estimates that biogas recovery systems are technically feasible at 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 at poultry and beef operations is growing as new technologies enter the market. Although these projects 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 projects at dairy and hog farms in the United States.

Challenges and Opportunities for California's Dairy Economy​Challenges and Opportunities for California’s Dairy Economy (PDF) Exit(149 pp, 6.4 MB, About PDF) 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 projects on livestock farms (Source: AgSTAR Livestock Anaerobic Digester Database).

 

Year Operational1 Newly Operational2 Shut Down Under Construction
2020 255 0 0 33
2019 255 11 2 0
2018 246 12 2 0
2017 236 7 4 0
2016 233 4 9 0
2015 238 7 4 0
2014 235 10 5 0
2013 233 29 3 0
2012 206 31 1 0
2011 176 26 9 0
2010 160 18 3 0
2009 142 24 15 0
2008 133 34 7 0
2007 106 18 3 0
2006 91 21 2 0
2005 72 15 2 0
2004 59 18 2 0
2003 44 7 1 0
2002 39 10 1 0
2001 31 6 1 0
2000 25 1 0 0

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.

* 2020 values are based on data as of March 2020.
** Data shown for operational digesters in 2000 represent cumulative totals from 1972-2000.

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 digesters at livestock farms.

 

System Type Count
Plug Flow* 97
Complete Mix 87
Covered Lagoon 56
Induced Blanket Reactor 5
Anaerobic Sequencing Batch Reactor 3
Fixed Film 2
Dry Digester 1
Other/Unknown 4

*Plug flow digesters include all modified plug flow digesters (for example, mixed plug flow and horizontal plug flow).

Learn more about the type of anaerobic digesters being used at livestock farms:

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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 since 2000. CHP is the most common end use, followed by electricity. The number of CHP and electricity projects steadily increased each year from 2000 to 2013. Since then, the electricity project count has become more stable, while the number of CHP projects continues to rise, albeit more slowly. Boiler and furnace fuel projects have also increased, but at a much slower rate than CHP and electricity projects. Renewable natural gas (RNG) projects, including pipeline injection and compressed natural gas (CNG) for vehicle fuel or other uses, have risen steadily since 2017. Projects that flare the biogas full time currently make up approximately 5 percent of all projects.

 

Year Combined Heat and Power Electricity Boiler/Furnace Fuel Flared Full Time CNG Pipeline Unknown
2019 122 90 13 13 19 7 1
2018 123 86 13 13 11 4 1
2017 123 83 13 13 3 3 1
2016 124 81 13 13 3 1 1
2015 126 82 13 13 4 1 3
2014 123 81 13 14 4 0 4
2013 120 84 12 13 5 0 4
2012 106 71 12 13 4 1 3
2011 95 54 11 14 3 1 1
2010 87 45 13 14 5 1 0
2009 78 37 11 14 2 2 0
2008 74 34 11 10 2 4 0
2007 66 21 11 6 0 1 1
2006 51 21 11 6 0 1 1
2005 37 20 9 4 0 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 2019, anaerobic digesters on livestock farms reduced GHG emissions by 4.63 million metric tons of CO2 equivalent (MMTCO2e).
    • 3.84 MMTCO2e direct methane reductions
    • 0.79 MMTCO2e emissions avoided
  • From 2000 through 2019, anaerobic digesters on livestock farms have reduced direct and indirect emissions by 43.8 MMTCO2e.
  • In 2019, energy generation from anaerobic digesters on livestock farms was approximately 1.28 million megawatt-hours (MWh) equivalent.

The chart below shows the amount of direct and indirect GHG emission reductions from anaerobic digesters on livestock farms since 2000. The chart shows a steady increase through 2013 with a total of 4.63 MMTCO2e in 2019.

 

Year Direct Reductions
(MMTCO2e)
Indirect Reductions
(MMTCO2e)
2019 3.839051914 0.791893912
2018 3.519185581 0.766562605
2017 3.187703032 0.751731939
2016 3.146180936 0.79076535
2015 3.072187665 0.804011634
2014 3.055574538 0.792912795
2013 3.011633346 0.754394412
2012 2.603844999 0.638171087
2011 2.005308403 0.469359495
2010 1.663142262 0.379223679
2009 1.484863516 0.318208264
2008 1.370641685 0.276505918
2007 0.941009528 0.165141667
2006 0.854999875 0.11694429
2005 0.616585375 0.085581146
2004 0.454869893 0.062473133
2003 0.324474919 0.047273093
2002 0.275149123 0.039121338
2001 0.227956086 0.029423847
2000 0.10177904 0.012581513

The following chart shows energy generation from electricity projects and non-electricity projects on livestock farms since 2000. The chart shows a gradual increase from 2000 through 2007 and then a more significant increase from 2008 through 2013. In 2019, AD systems on livestock farms generated the equivalent of approximately 1.28 million MWh of electricity.

 

Year Electricity Projects
(Million kWh/yr)
Non-Electricity Projects
(Million kWh/yr Equivalent)
2019 1013.615727 265.1718597
2018 1027.586978 71.51344319
2017 984.0847732 39.1229583
2016 991.6320312 19.25995451
2015 1008.38663 3.712521761
2014 1011.340638 3.712521761
2013 976.4117182 3.676850821
2012 775.2936262 57.1559655
2011 542.306045 56.93645202
2010 437.205717 57.26572224
2009 350.141787 81.32648848
2008 292.810394 97.60386762
2007 156.380459 19.515203
2006 120.012151 19.515203
2005 77.237252 17.32006818
2004 61.471305 17.32006818
2003 44.5417 0.713418816
2002 31.09346 0.219513482
2001 20.916709 0.219513482
2000 17.559804 0.219513482

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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 mature 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
2020 33 0 255 0
2019 0 11 244 -2
2018 0 12 234 -2
2017 0 7 229 -4
2016 0 4 229 -9
2015 0 7 231 -4
2014 0 10 225 -5
2013 0 29 204 -3
2012 0 31 175 -1
2011 0 26 150 -9
2010 0 18 142 -3
2009 0 24 118 -15
2008 0 34 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 -1
2000 0 1 24 0