Waste-to-energy in Mexico: technical potential for biogas production and greenhouse gas mitigation from the anaerobic digestion of municipal solid waste

Abstract

The generation of waste has been historically a source of environmental disturbance that triggered the development of technologies to minimize it. The anaerobic digestion of municipal solid waste has emerged in the last decades as a feasible solution. Its effectiveness to stabilize the waste and the added value of providing biogas during the process makes it an attractive solution. In Mexico, the implementation of these facilities is still at a preliminary stage, but it could contribute to facing the multiple problems derived from the disposal of solid waste in sanitary landfills and dumpsites, such as methane emissions that contribute to climate change. This case study provides an insight to the technical and the country-specific limitations to deploy the potential for biogas production. The energy that this biofuel could produce is estimated in the range of 25 – 29 PJ per year that could substitute the use of fossil fuels to meet the energy demand of the country. The energy output varies according to the use given to the biogas: cogeneration of heat and power, injection to the natural gas network or feeding gas-powered vehicles. Besides, this could have a direct effect on the emission of greenhouse gases to the atmosphere: between 1.4 and 1.9 Mt CO2-eq per year could be saved by using biogas. Additionally, this mitigation would be larger due to the diversion of 14 million tons of organic waste from being disposed: 11.7 Mt CO2-eq per year. This implies a positive contribution towards meeting the commitments made by Mexico to reduce its carbon intensity. The Nationally Determined Contributions implies a reduction of 22% of the greenhouse gas emissions from the waste sector for 2030 in comparison with the baseline. If this mitigation potential is deployed, up to 87% of the internationally compromised targets could be achieved. To conclude, a review is made of the existing policies in Mexico and in other countries to enhance the implementation of anaerobic digestion technologies to treat municipal solid waste.