Microbes Could Supply Up to 5.5% of Electricity by 2050
Researchers from the MIT Joint Program on the Science and Policy of Global Change have found that anaerobic digesters could supply as much as 5.5% of national electricity generation by 2050. Anaerobic bacteria that break down organic wastes produce methane that can be used to generate renewable electricity. Diverting methane emissions towards electricity generation also reduces total U.S. greenhouse gas emissions and may qualify for low-carbon energy subsidies and methane-reduction credits. Anaerobic digesters also reduce odor and pathogens in manure storage, and digested manure can be applied to crops as a fertilizer. Researchers used the MIT Emissions Prediction and Policy Analysis (EPPA) model to test the effect of emissions scenarios on the adoption of anaerobic digesters. The researchers estimate that cattle, swine, and poultry manure deposited in lagoons or pits currently has the potential to produce 11,000 megawatts of electricity. The study found that, under a representative emissions mitigation scenario, anaerobic digesters are introduced in 2025 when the price of CO2e is $76/ton. By 2050, use of anaerobic digesters would mitigate 151 million metric tons of CO2e, mostly from methane abatement.
Zaks, D. P. M., N. Winchester, C. J. Kucharik, C. C. Barford, S. Paltsev, and J. M. Reilly. 2011. “Contribution of Anaerobic Digesters to Emissions Mitigation and Electricity Generation Under U.S. Climate Policy,” Environmental Science and Technology 45(16), 6735-42. DOI:10.1021/es104227y.