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AgSTAR

AgSTAR Data and Trends

There are 248 anaerobic digester projects operating on livestock farms in the United States, helping to reduce greenhouse gas emissions from methane.  Of these, 104  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 operating digester projects on livestock farms (Source: AgSTAR Livestock Anaerobic Digester Database).

 

Year Number of Operating Digester Projects
2018 248
2017 242
2016 241
2015 245
2014 241
2013 238
2012 214
2011 182
2010 162
2009 145
2008 135
2007 107
2006 92
2005 73
2004 60
2003 44
2002 39
2001 31
2000 25

Anaerobic digesters operating at livestock farms use different technologies to generate power. Complete mix and mixed plug flow designs were used in the majority of anaerobic digesters at livestock farms in 2018.

 

System Type Count
Plug Flow* 100
Complete Mix 87
Covered Lagoon 48
Induced Blanket Reactor 5
Anaerobic Sequencing Batch Reactor 3
Fixed Film 2
Dry Digester 1
Other/Unknown 2

*Plug flow digesters combine 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. Combined heat and power generates electricity and uses 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 2000 through 2018. Combined heat and power (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. Projects that flare the biogas full time made up approximately 5 percent of all projects in 2018.

 

Year Combined Heat and Power Electricity Boiler/Furnace Fuel Flared Full Time CNG Pipeline Unknown
2018 123 91 15 14 9 5 1
2017 123 86 15 14 7 3 1
2016 124 86 15 14 7 1 1
2015 126 86 15 14 7 1 3
2014 123 84 15 15 7 0 4
2013 120 86 14 14 7 0 4
2012 107 75 14 14 7 1 3
2011 96 58 12 14 5 1 1
2010 88 47 12 14 5 1 0
2009 79 39 11 14 2 2 0
2008 75 35 11 10 2 4 0
2007 66 22 11 6 0 1 1
2006 51 22 11 6 0 1 1
2005 37 21 9 4 0 1 1
2004 28 20 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 2018, anaerobic digesters on livestock farms reduced GHG emissions by 4.27 million metric tons of CO2 equivalent (MMTCO2e).
    • 3.46 MMTCO2e direct methane reductions
    • 0.81 MMTCO2e emissions avoided
  • Since 2000, anaerobic digesters on livestock farms have reduced direct and indirect emissions by 39.3 MMTCO2e.
  • In 2018, energy generation from anaerobic digesters on livestock farms was approximately 1.14 million megawatt-hours (MWh) equivalent.

The chart below shows the amount of direct and indirect GHG emission reductions from anaerobic digesters on livestock farms from 2000 through 2018. The chart shows a steady increase through 2013 with an estimated total of 4.27 MMTCO2e in 2018.

 

Year Direct Reductions
(MMTCO2e)
Indirect Reductions
(MMTCO2e)
2018 3.455651068 0.812597296
2017 3.175414633 0.782160807
2016 3.14757268 0.82475967
2015 3.059843265 0.82761892
2014 3.039405452 0.816662297
2013 2.987245835 0.773893719
2012 2.591218135 0.674196876
2011 1.991814503 0.476485765
2010 1.639330528 0.37573007
2009 1.468957353 0.315447516
2008 1.35337091 0.274165632
2007 0.949279277 0.165602442
2006 0.863269624 0.120060226
2005 0.624855124 0.088739865
2004 0.463139642 0.065712661
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 from 2000 through 2018. The chart shows a gradual increase from 2000 through 2007 and then a more significant increase from 2007 through 2013. In 2018, AD systems on livestock farms generated the equivalent of approximately 1.14 million MWh of electricity.

 

Year Electricity Projects
(Million kWh/yr)
Non-Electricity Projects
(Million kWh/yr Equivalent)
2018 1044 93
2017 1002 39
2016 1016 20
2015 1023 4
2014 1028 4
2013 989 4
2012 803 57
2011 566 57
2010 444 57
2009 357 81
2008 298 98
2007 162 20
2006 125 20
2005 82 17
2004 67 17
2003 45 1
2002 31 0
2001 21 0
2000 18 0

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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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