Producing energy from landfill methane ranks #58 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric emissions by the equivalent of 2.5 gigatons of carbon dioxide by 2050, at a net cost of -US$1.8 billion and net savings of $67.6 billion.
“Landfills are a top source of methane emissions,” writes Drawdown, “releasing 12% of the world’s total—equivalent to 800 million tons of carbon dioxide.” The global annual volume of solid waste is projected to increase by up to 70%, to 2.4 billion tons, by 2025, the chapter notes. And landfills are likely to remain a blight on soil, air, and water for years to come, especially in low-income countries. So the need to manage the accumulated biogas in these anaerobic environments, described by Drawdown as “roughly an equal blend of carbon dioxide and methane, with a smattering of other gases,” grows ever more urgent.
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The technology required to capture, compress, and purify biogas into fuel is “relatively simple”, Drawdown states. Which means landfill methane capture is primed to deliver a dual climate benefit: it prevents emissions from waste, while displacing coal, oil, or natural gas that might otherwise be burned.
Drawdown does point to an important disconnect on landfill methane capture. “According to a study of U.S. landfills, methane collection at closed sites was 17% more efficient than at sites actively receiving waste,” it states. “But open landfills—which have the most active decomposition due to fresh deposits—were responsible for more than 90% of methane emissions.”