Design of a Centralized Bioenergy Unit at Comarca Lagunera, Mexico: Modeling Strategy to Optimize Bioenergy Production and Reduce Methane Emissions

Abstract

A centralized bioenergy unit was simulated, focusing on optimizing the manure transport chain, installing a centralized biogas plant, operation costs of the process, biogas upgrading, organic fertilizer production, and economic analyses. Comarca Lagunera from northeast Mexico was chosen as a study zone due to the existing number of dairy farms and livestock population (64,000 cattle heads). Two scenarios were analyzed: The first centralized scenario consisted of selecting one unique location for the anaerobic digesters for the 16 farms; the second decentralized scenario consisted of distributing the anaerobic digesters in three locations. Optimal locations were determined using mathematical modeling. The bioenergy unit was designed to process 1600 t/day of dairy manure. Results indicated that biomethane production was a more profitable option than generating electricity with non-purified methane. The amount of biomethane production was 58,756 m3/day. Economic analysis for centralized bioenergy unit scenario showed a net production cost of USD $0.80 per kg of biomethane with a profit margin of 14.4% within 10.7 years. The decentralized bioenergy unit scenario showed a net production cost of USD $0.80 per kg of biomethane with a profit of 12.9% within 11.4 years. This study demonstrated the techno-economical and environmental feasibility for centralized and decentralized bioenergy units.