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AgSTAR

AgSTAR Data and Trends

There are 253 anaerobic digesters operating on livestock farms in the United States, helping to reduce greenhouse gas emissions from methane. 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 digesters on livestock farms (Source: AgSTAR Livestock Anaerobic Digester Database).

 

Year Number of Operating Digesters
2018 253
2017 250
2016 248
2015 246
2014 242
2013 234
2012 211
2011 181
2010 154
2009 135
2008 114
2007 89
2006 74
2005 56
2004 46
2003 31
2002 25
2001 18
2000 15

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 2017.

 

System Type Count
Plug Flow* 103
Complete Mix 87
Covered Lagoon 43
Induced Blanket Reactor 5
Anaerobic Sequencing Batch Reactor 3
Fixed Film 2
Unknown/Other 5

*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 2017. 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 2017.

 

Year Combined Heat and Power Electricity Boiler/Furnace Fuel Flared Full Time CNG Pipeline Unknown
2017 125 90 15 14 6 3 1
2016 125 89 15 14 6 1 1
2015 124 88 15 14 6 0 2
2014 121 90 15 15 6 0 3
2013 119 89 14 14 6 0 3
2012 108 77 14 14 6 1 2
2011 97 60 12 14 4 1 1
2010 89 48 12 14 4 1 0
2009 80 40 11 14 1 2 0
2008 75 36 11 10 1 4 0
2007 66 23 11 6 0 1 1
2006 51 23 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 2017, anaerobic digesters on livestock farms reduced GHG emissions by 3.95 million metric tons of CO2 equivalent (MMTCO2e).
    • 3.11 MMTCO2e direct methane reductions
    • 0.84 MMTCO2e emissions avoided
  • Since 2000, anaerobic digesters on livestock farms have reduced direct and indirect emissions by 34.6 MMTCO2e.
  • In 2017, energy generation from anaerobic digesters on livestock farms was approximately 1.08 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 2017. The chart shows a steady increase through 2013 with an estimated total of 3.95 MMTCO2e in 2017.

 

Year Direct Reductions
(MMTCO2e)
Indirect Reductions
(MMTCO2e)
2017 3.107799 0.845526
2016 3.031144 0.840556
2015 2.937968 0.821901
2014 2.959310 0.828159
2013 2.872028 0.795915
2012 2.472224 0.672904
2011 2.021629 0.465696
2010 1.651440 0.369123
2009 1.481067 0.306218
2008 1.364630 0.265527
2007 0.960538 0.161310
2006 0.874529 0.134101
2005 0.624855 0.100459
2004 0.463140 0.074157
2003 0.324475 0.052771
2002 0.275149 0.042846
2001 0.227956 0.031863
2000 0.101779 0.014573

This chart shows energy generation from electricity projects and non-electricity projects on livestock farms from 2000 through 2017. The chart shows a gradual increase from 2000 through 2007 and then a more significant increase from 2007 through 2013. In 2017, AD systems on livestock farms generated the equivalent of approximately 1.08 million megawatt-hours of electricity.

 

Year Electricity Projects
(Million kWh/yr)
Non-Electricity Projects
(Million kWh/yr Equivalent)
2017 1040 39
2016 1038 20
2015 1018 4
2014 1026 4
2013 983 4
2012 804 57
2011 569 57
2010 440 57
2009 349 81
2008 290 98
2007 155 20
2006 119 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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