Methane emission and bioenergy potential from livestock manures in Mexico

Abstract

Methane is an important greenhouse gas contributing to the global climate change leading to global warming and livestock accounts as one of the major sources of methane emission. Although, Intergovernmental Panel on Climate Change has developed guidelines to quantify emissions from enteric fermentation and manure management, it is recently reported that the National methane emission in U.S. is underestimated by a factor of 1.5–1.7. This study estimated the emission of methane in Mexico based on the animal census data from 2012. On an average, the total livestock in Mexico produced about 344 275 t·d−1 of animal manure. Further, a manure map of different states of Mexico was developed, and their potential methane emission was estimated. It is calculated that the total methane emission from enteric fermentation and manure is about 40 447.68 and 1307.04 Gg CO2 Eq., respectively. In the case of animal manures, beef and swine manures, respectively, contributed about 47% and 27% of total methane emission. Based on the data obtained, the bioenergy potential of Mexico by way of manure treatment using anaerobic digestion was calculated and is approximately 5910.35 TJ, which can generate 410.41 GWh of electricity and reduce emissions of methane by 2240.64 Gg CO2 Eq. The data clearly suggest that anaerobic digestion is a sustainable technology, not only for generation of renewable bioenergy but also for significant reduction in methane emission from animal manures.