Mexico: Implementation of biogas technologies in a WaCCliM partner-utility |
The status quo of biogas technologies in the Mexican water and wastewater sector
The WaCCliM project is being implemented in three partner countries, two of which are Mexico and Peru. Mexico is unconditionally committed to reduce its GHG emissions by 22% by 2030 compared to a business-as-usual scenario. However, conditional commitments would allow for increased emissions mitigation of up to 36%. Mexican water utilities will need to contribute to this reduction, but they already face a difficult task in meeting users’ demands. Obstacles like low tariffs, high water consumption and a complicated legal framework have led to unsustainable water abstraction, high energy costs, water losses and inadequate wastewater treatment. In Mexico, GIZ is working with the National Water Commission, the Ministry of Environment and Natural Resources and the National Water Association of Mexico. These partners have participated in the dissemination of the low-carbon approach in the urban water sector, including through network meetings of utilities and the development of standards for biogas and energy generation projects.
SITRATA, the wastewater treatment utility in the city of San Francisco del Rincón is adapting measures to a sustainable, low-carbon wastewater management. The wastewater treatment plant (WWTP) is based on an activated sludge system. Currently, emissions of ~2,500 tCO2e per year are being avoided, which was achieved mostly by expanding wastewater treatment coverage from less than half of the city to more than 80%. The utility is now investigating further measures to reduce emissions and operational costs and increase resilience to climate risks in the city’s wastewater system. In this context, sewage sludge plays a significant role. Even though sludge has very little monetary value and many utilities struggle with its management, it can be a source of renewable energy that can replace fossil fuels. At the moment, biogas is only being used for the production of thermal energy at SITRATA. However, the utility is considering the implementation of a cogeneration system to convert biogas to electrical energy as this would bring along several benefits. Firstly, operational costs and GHG emissions of the WWTP could be reduced, as the utility would produce its own electricity, making it less dependent on price fluctuations of the national grid. Secondly, the utility would increase its efficiency as the biogas would not be flared.
Only a low number of WWTPs in Mexico have infrastructure for biogas capture, which hinders an effective supply chain structure and increases costs for replacement parts. However, recent studies have identified 27 large facilities with a potential for cogeneration systems for biogas use in the country. The WaCCliM project has facilitated the participation of different network meetings with other utilities that operate WWTPs with cogeneration systems. By constructing partnerships and sharing experiences for up-scaling, we hope that more utilities will follow this way.
The legislation for the production of biogas in Mexico is still under development. Until now, there is no specific regulation for the management and use of biogas. However, there are several national norms related to the topic that can serve as an orientation for the establishment of a norm that regulates the production and the use of biogas for energy generation. Regardless of this, the anaerobic treatment of wastewater is considered to have high potential in Mexico and Latin America in general: even if biogas is not used widely yet, the reduction in GHGs and good results in life cycle assessments show that the use of biogas for electricity generation is the technological option that should be privileged in the future. Therefore, it is necessary to develop a standard that contains all the aspects involved, from the conduction of the biogas, its storage, incineration, treatment and use, with special emphasis on security aspects. Furthermore, competence standards for engineers, technicians and operators of WWTPs need to be established in order to ensure the proper management and maintenance of biogas technologies in the utilities.