Continuing to Use Firewood or Switching to Biogas: Economic and Environmental Benefits of Low-Cost Tubular Biodigesters in Chiapas, Mexico

Biogas production from animal manure has huge potential in mitigating greenhouse gas emissions and replacing the higher environmental footprint energy sources. This study aimed to assess the technical functionality, environmental benefits, and economic advantages of low-cost biodigesters suitable for rural areas, which can produce biogas from animal manure. Four low-cost polyethylene tubular biodigesters with a concrete retaining wall with capacities ranging from 4 to 14 m3 were installed in small dairy production units in Chiapas, Mexico. Four profitability indicators were calculated. The IPCC’s methodology was used to calculate emissions from biogas and firewood burning, and the emission reduction from manure management. These biodigesters generate between 526 and 1993 m3 of biogas year−1 and represent a savings of USD 197–744 year−1 in energy costs. The four profitability indicators were favorable. Moreover, these biodigesters reduce 70–73% of greenhouse gas (GHG) emissions through manure management, that is, between 1.5 and 5.1 t CO2e year−1, and 1.3–5.1 t CO2e year−1 from firewood displacement. These findings provide critical insights into the potential of sustainable and low-cost biodigesters that can be implemented effectively in small-scale dairy farms in rural areas in many parts of the world.