Buildings and Cities
Over the course of a century, methane has 34 times the greenhouse effect of carbon dioxide. Landfills are a top source of methane emissions, releasing 12 percent of the world’s total. Landfill methane can be tapped, captured, and used as a fairly clean energy source for generating electricity or heat, rather than leaking into the air or being dispersed as waste. The climate benefit is twofold: prevent landfill emissions and displace coal, oil, or natural gas that might otherwise be used.
Most landfill content is organic matter: food scraps, yard trimmings, junk wood, wastepaper. Their decomposition produces biogas, a roughly equal blend of carbon dioxide and methane accompanied by a smattering of other gases. Ideally, those wastes would be recycled, composted, or digested. But as long as landfills are piling up, we must manage the methane coming out of them.
The technology to manage biogas is relatively simple. Dispersed, perforated tubes are sent down into a landfill’s depths to collect gas, which is piped to a central collection area where it can be vented or flared. Better still, it can be compressed and purified for use as fuel in generators, garbage trucks, or mixed into natural gas supply.
Technical summaries for each solution will be available May 1, 2017.