AgSTAR Data and Trends

U.S. Highlights

Projects - 400 operational projects in the United States (as of June 2024), comprising the following types of livestock:
► 343 Dairy
► 50 Hog
► 8 Poultry
► 9 Beef
Note: Total exceeds 400 because some systems accept manure from more than one animal type.

Benefits in 2023
► Direct and indirect GHG emissions avoided: 14.8 MMTCO2e
► Energy generated: 3.29 million MWh equivalent

In the United States, as of June 2024, there are 400 manure-based anaerobic digestion systems reducing methane emissions by collecting biogas from the degradation of animal manure. 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 Facilities

Market 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 explores the potential of dairy biogas systems to reduce environmental impacts while generating energy and/or income for dairies.

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 37 systems that came online in 2023, at least 6 more have started up in 2024, and another 73 are currently under construction or undergoing modification to upgrade biogas to renewable natural gas (RNG).

 

Year Operational1 Newly Operational2 Shut Down
2024* 400 6 0
2023 394 37 0
2022 357 36 2
2021 323 53 0
2020 270 19 1
2019 252 15 4
2018 241 11 4
2017 234 9 4
2016 229 5 10
2015 234 8 5
2014 231 11 6
2013 226 29 3
2012 200 30 1
2011 171 26 9
2010 155 18 3
2009 140 24 15
2008 131 33 8
2007 106 18 3
2006 91 21 2
2005 73 15 2
2004 60 19 2
2003 44 7 1
2002 39 9 1
2001 32 7 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.
3 In cases where the start year for an AD system is known but the shutdown year is unknown, the system is conservatively counted as operational only for its first year of operation. This may cause small discrepancies between the number of operational projects from one year to the next when compared against the number of systems known to be starting up and shutting down each year.

*2024 values are based on data available through June 2024

There are a number of different types of anaerobic digestion systems. Covered lagoons and mixed plug flow designs are currently the most common anaerobic digestion systems that accept livestock manure.

 

System Type Count
Plug Flow* 107
Complete Mix 105
Covered Lagoon 174
Induced Blanket Reactor 5
Anaerobic Sequencing Batch Reactor 3
Fixed Film 2
Other/Unknown 4

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

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 (CNG) 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. CNG as vehicle fuel is now the most common end use, followed by CHP and electricity.

  • The number of CHP and electricity projects steadily increased each year from 2000 to 2013. Since then, the number of CHP and electricity projects has remained relatively stable.
  • The number of boiler and furnace fuel projects increased much more slowly from 2000 to 2013 and has seen little change since.
  • RNG projects, including pipeline injection and compressed natural gas (CNG) for vehicle fuel or other uses, have risen steadily and significantly since 2017. The rise in the number of systems producing CNG has been particularly sharp in the last three years.
  • Projects that flare the biogas full time currently make up approximately 3.2 percent of all projects.
 

Year Combined Heat and Power Electricity Boiler/ Furnace Fuel Flared Full Time CNG Pipeline Unknown
2024 109 82 13 13 134 57 3
2023 109 82 13 13 132 53 3
2022 109 80 13 13 108 43 2
2021 111 80 13 13 80 34 3
2020 112 79 13 13 36 24 3
2019 119 81 13 14 22 10 2
2018 122 80 13 14 10 5 1
2017 123 80 13 14 5 3 1
2016 125 75 13 14 4 1 1
2015 126 77 13 14 5 1 3
2014 122 77 13 15 5 0 4
2013 120 80 12 13 6 0 4
2012 106 67 12 13 5 1 3
2011 94 51 11 15 4 1 1
2010 87 42 13 15 6 1 0
2009 77 35 11 15 3 2 0
2008 73 32 11 11 3 4 0
2007 66 21 12 5 1 1 1
2006 51 21 12 5 1 1 1
2005 37 21 10 3 1 1 1
2004 28 19 9 2 0 1 1
2003 21 13 7 2 0 0 1
2002 18 10 8 2 0 0 1
2001 14 9 6 2 0 0 1
2000 11 7 4 2 0 0 1

Environmental Benefits

  • In calendar year 2023, manure-based anaerobic digesters reduced GHG emissions by 14.8 million metric tons of CO2 equivalent (MMTCO2e).
    • 13.8 MMTCO2e direct methane reductions
    • 0.98 MMTCO2e emissions avoided
  • From 2000 through 2023, manure-based anaerobic digesters have reduced direct and indirect emissions by 95.7 MMTCO2e.
  • In 2023, energy generation from manure-based anaerobic digesters was approximately 3.29 million megawatt-hours (MWh) equivalent.

The chart below shows the direct and indirect GHG emission reductions from manure-based anaerobic digesters since 2000. The chart shows a steady increase through 2013. 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)
2023 13.86 0.98
2022 11.38 0.98
2021 9.98 0.96
2020 6.65 0.88
2019 5.08 0.80
2018 4.19 0.77
2017 3.63 0.73
2016 3.54 0.76
2015 3.48 0.78
2014 3.64 0.78
2013 3.56 0.74
2012 2.86 0.62
2011 2.35 0.47
2010 1.95 0.38
2009 1.74 0.32
2008 1.61 0.28
2007 1.09 0.17
2006 0.98 0.12
2005 0.72 0.09
2004 0.53 0.07
2003 0.38 0.05
2002 0.33 0.04
2001 0.26 0.03
2000 0.12 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, then again from 2017 on. Energy generation has increased significantly over the last few years, due in large part to the increase in RNG projects. In 2023, manure-based anaerobic digestion systems generated the equivalent of approximately 3.29 million MWh of electricity.

 

Year Electricity Projects (Million kWh/yr) Non-Electricity Projects (Million kWh/yr Equivalent)
2023 952.2 2335.5
2022 921.9 1716.0
2021 941.0 1372.3
2020 886.4 1199.3
2019 905.5 686.9
2018 974.4 238.1
2017 950.1 38.8
2016 948.2 20.0
2015 967.2 3.7
2014 982.4 3.7
2013 945.7 3.7
2012 748.2 61.4
2011 540.0 61.2
2010 432.6 61.6
2009 343.5 86.2
2008 286.2 102.8
2007 154.0 19.9
2006 117.6 19.9
2005 75.1 17.7
2004 64.0 17.7
2003 44.5 0.7
2002 31.1 0.2
2001 21.8 0.2
2000 17.6 0.2

Value of Anaerobic Digester Biogas and Coproducts

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

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) 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.
Year Under Construction Newly Operational Operational Shut Down
2024 73 6 394 0
2023 0 37 357 0
2022 0 36 321 -2
2021 0 53 270 0
2020 0 19 251 -1
2019 0 15 237 -4
2018 0 11 230 -4
2017 0 9 225 -4
2016 0 5 224 -10
2015 0 8 226 -5
2014 0 11 220 -6
2013 0 29 197 -3
2012 0 30 170 -1
2011 0 26 145 -9
2010 0 18 137 -3
2009 0 24 116 -15
2008 0 33 98 -8
2007 0 18 88 -3
2006 0 21 70 -2
2005 0 15 58 -2
2004 0 19 41 -2
2003 0 7 37 -1
2002 0 9 30 -1
2001 0 7 25 0
2000 0 1 24 -1

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Last updated on November 27, 2024