Landfill methane recovery and use under deep uncertainty: a satellite-constrained Monte Carlo decision model for the Norte III landfill, Buenos Aires

Manuscript (version 2) prepared for Waste Management. Very large landfills are major methane sources, but site decisions rarely combine operator-reported capture, independent emission estimates and the economics of competing gas uses. A Latin-hypercube Monte Carlo decision model (300,000 draws) of landfill-gas generation, collection, surface emission and oxidation, selective covers, biomethane upgrading, additional power generation and photovoltaics is applied to the Norte III landfill in Buenos Aires. A bottom-up generation prior is constrained by satellite emission estimates at their own observation date (2022) and carried forward to the 2025-26 decision period, with three observation-error models; the inferred collection efficiency is about 0.13 (2022) and 0.14 (2025-26), a model output, not a measurement. Methane, carbon and energy balances close for every scenario. Under the assumed no-credit conditions, none of the eight integrated intervention scenarios has a positive median incremental net present value; additional engines on surplus gas, reported separately, are profitable in most draws at merchant tariffs, whereas biomethane needs about US$0.46 per Nm3 (US$14 per MMBtu). A cover reduces net emissions only when the captured share of blocked gas exceeds an analytic break-even. Economic priors are anchored to dated Argentine benchmarks; conclusions are tested against correlated inputs, alternative priors, structural alternatives, tax, financing, credits and time-varying gas supply.