Landfill Gas Valorization for Electricity and Carbon Credits in a Mid-Sized Mexican Metropolitan Area

Rapid urban growth in Latin America challenges municipal solid waste (MSW) management. This study models landfill-gas (LFG) energy recovery and carbon-credit generation in the Cuernavaca metropolitan area, Mexico. A landfill receiving 3.93 × 106 Mg of MSW over ten years would generate 2.65 × 105 Mg of CH4 over a 21-year horizon with the US EPA LandGEM defaults, and 1.51–1.85 × 105 Mg with parameters derived from the regional waste composition and climate. Accounting explicitly for gas-collection efficiency (75%), cover oxidation, methane slip and biogenic CO2, enclosed flaring reduces greenhouse-gas emissions by 66.7%, and staged gas-engine generation (12 MW) reduces them by 71.8%, delivering 1.12 × 106 MWh of electricity. Collection efficiency governs the percentage reduction, whereas the gas-generation parameters govern the absolute methane and energy. At 0.075 USD kWh−1, 1.8 million USD MW−1 and a 10% discount rate, the net present value is 15.7 million USD with full carbon crediting (7.6–12.7 million USD with regional parameters) and 4.1 million USD without credits. Viability without credits is conditional. It is lost below 0.065 USD kWh−1, above 2.08 million USD MW−1, when collection starts two years after deposition, or when the project bears delivered-supply network charges. Credit revenue falls from 32.4 to 2.3 million USD if regulatory flaring defines the baseline. Gas engines offer the best compromise; fuel cells are financially unviable.