The Path to Drawdown: Landfill Gas
Although carbon dioxide is the greenhouse gas that’s often talked about, methane has 34 times the global warming effect of CO2 over the course of a century. And the biggest source of methane are landfills, accounting for 12% of total global methane emissions.
Methane comes from the organic matter in landfills like food scraps, yard waste, junk wood, and waste paper. Their decomposition produces biogas, a roughly equal mix of carbon dioxide, methane, and small amounts of other gases.
As diets change, waste is reduced, and recycling and composting grow, we’re hopeful that landfill waste as a whole will diminish. But for now, as the modern way of life continues and organic matter in landfills continues to decompose, landfills and landfill methane emissions keep growing.
The way to manage this is landfill methane capture. This process involves capturing methane generated from anaerobic digestion of municipal solid waste in landfills and incinerating the captured biogas to generate electricity. This solution has double benefits: it captures methane from landfills that’s far worse for global warming, and it replaces conventional electricity-generating technologies like coal, oil, and natural gas power plants.Currently, enough methane is captured to generate 33.1 TWh of electricity, or 0.13% of total electricity generated worldwide. In the best-case scenario for 2050, landfills wouldn’t exist, and integration and waste feedstock availability would mean a net greenhouse gas sequestration, rather than emission. In a less ideal scenario, 70% of the world’s landfills will have adopted methane capture, and they help reduce 2.2 gigatons of CO2e between 2020 and 2050