Biodigesters: Converting waste into energy
Biodigesters, also called anaerobic digesters, capture and combust methane created by decomposition, avoiding methane emissions and generating renewable energy. When organic material decomposes without oxygen, it produces methane, a potent greenhouse gas which over the course of a century has 20 to 25 times the ability of an equivalent amount of carbon dioxide to warm the planet. Biodigesters combust this methane, ensuring it is not released into the atmosphere.
Most biodigester projects are developed at the manure lagoons of dairy farms, and protocols for these projects have been established. Despite the fact that nearly every digester built at dairy farms in the United States receives carbon finance, these digesters are still far from common practice. Of about 100,000 dairy farms in the United States, there are estimated to be only 62 biodigesters.
Reducing livestock emissions with technologies such as biodigesters is essential to combating climate change. After aggregating the emissions associated with producing feed, raising livestock, and processing and transporting animal products, the Food and Agricultural Organization of the United Nations estimate that the world's livestock are responsible for 18% of greenhouse gas emissions, which is more than the global emissions associated with transportation.