Growth in the number of anaerobic digesters is back on the rise according to the latest data from USDA. The Economic Research Service released this chart showing that as of 2021, there are a total of 322 on-farm systems.
An anaerobic digestor is an air-tight vessel in which bacteria digest or decompose organic waste such as manure. This produces biogas, which can then be sold or used to make electricity. Roughly 78% of all of these facilities in the U.S. are found on dairy farms, especially in California, Wisconsin and Pennsylvania.
Anaerobic digesters were first adopted in the 1970s, however steady growth of on-farm anaerobic digestion systems did not pick up until the 1990s. Growth then persisted until about 2013, after which it slowed considerably, then began increasing again. Recent growth in the number of digesters corresponds to increased demand for renewable fuel as a result of carbon credit trading and incentive programs, according to the USDA. Additionally, dairies have built more covered lagoons as their costs have decreased.
