AgSTAR Data and Trends
In the United States, there are 317 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.
- Anaerobic digestion potential for livestock farms in the United States
- Anaerobic digester data and trends
- Biogas data and trends
- Environmental benefits
- Value of anaerobic digester biogas and coproducts
- State data and trends
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 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 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 44 systems that have come online so far this year, another 38 are currently under construction or undergoing modification to upgrade biogas to renewable natural gas (RNG).
|Year||Operational1||Newly Operational2||Shut Down|
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.
*2021 values are based on data as of September 2021
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.
|Induced Blanket Reactor||5|
|Anaerobic Sequencing Batch Reactor||3|
Learn more about the type of anaerobic digesters being used for livestock manure:
- Anaerobic System Design and Technology describes the most common digester designs in more detail and includes example photos and diagrams.
- The AgSTAR Anaerobic Digester Database identifies the design features of manure-based anaerobic digesters in the United States.
- Stories from the Farm highlight experiences of anaerobic digester operators.
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 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 year.
- 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|
- In calendar year 2020, manure-based anaerobic digesters reduced GHG emissions by 5.29 million metric tons of CO2 equivalent (MMTCO2e).
- 4.44 MMTCO2e direct methane reductions
- 0.83 MMTCO2e emissions avoided
- From 2000 through 2020, manure-based anaerobic digesters have reduced direct and indirect emissions by 48.3 MMTCO2e.
- A projected reduction in direct and indirect emissions of 5.95 MMTCO2e is expected from anaerobic digesters on livestock farms in calendar year 2021
- In 2020, energy generation from manure-based anaerobic digesters was approximately 1.59 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 with a projected total of 5.95 MMTCO2e in 2021. 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)|
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 increase in RNG projects. In 2021, manure-based anaerobic digestion systems are expected to generate the equivalent of approximately 1.73 million MWh of electricity.
|Year||Electricity Projects (Million kWh/yr)||Non-Electricity Projects (Million kWh/yr Equivalent)|
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
- The Database of State Incentives for Renewable Energy (DSIRE) is a comprehensive source of information on state, local, utility and selected federal incentives that promote renewable energy.
- The State Energy Portal Online for Consumers provides a comprehensive view of energy data and information. The tool can help you compare state energy data and rankings, customize maps and charts, and view state rankings of energy production, consumption, prices, and more.
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:
- The National Conference of State Legislatures, 2014 update provides state-by-state RPS information.
- The Database of State Incentives for Renewable Energy (DSIRE) summarizes state RPS policies and can help you determine whether and how biogas recovery can meet your state RPS standard.
- 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|