This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy.
Image courtesy of Harvest Power. Harvest Power is a member of AEE's Business Council. Learn more about membership here.
Anaerobic digestion (AD) is a process by which organic materials, such as livestock manure, food scraps, and municipal or industrial wastewater, are broken down by microorganisms in the absence of oxygen. The product of AD is biogas, a gas mixture comprised primarily of methane and carbon dioxide. AD is one of several options for converting organic matter into useful energy. Different digester types can be used, from simple covered lagoons at animal farms to more sophisticated above-ground steel or concrete tanks. Today, most biogas is burned to generate electricity on-site, but it can also be purified and made into a pipeline-quality substitute for natural gas, including compressed natural gas (CNG) for vehicles. Fats, oils, and grease can be added to manure or wastewater (co-digestion) to enhance energy production. AD is often used in conjunction with combined heat and power for efficient electricity and heat generation, such as on dairy farms and at wastewater treatment plants.