How Today’s Trash Can Generate Tomorrow’s Energy
Solid waste disposal is one of the most critical issues facing cities today. Many cities are growing at unprecedented rates and municipal landfills around the world are filling up.
In the face of this challenge, some cities are exporting their trash to other regions, and paying billions of dollars to do so. But transporting trash outside of city limits involves generating more pollution.
Sao Paulo has a different strategy. Spurred by financial incentives offered by the Kyoto Protocol for reducing greenhouse gases, the city is turning pollution into profit with its “Bandeirantes Landfill Gas to Energy Project.”
This project captures energy from methane gas produced by millions of tons of waste deposited at the Bandeirantes landfill. Methane is typically a major public health risk to communities adjacent to landfills, due to its explosive properties. It is also a major offender as a high-potency greenhouse gas contributing to global warning. But unlike some of the other gases produced at landfills, methane can be a valuable energy source. The gas collected at the Bandeirantes landfill is sold as fuel to the Bandeirantes Thermoelectric power plant--an onsite clean energy power plant built in 2003 that provides energy for about 400,000 residents of the greater Sao Paulo region.
Further, although methane as a byproduct is a contributor to global warming, when used for fuel it is a clean energy source. Thus methane gas harvested at the Bandeirantes landfill has resulted in an estimated reduction of more than a million tons of CO2.
Bandeirantes combined with other efforts to use biogas as fuel in Sao Paulo have resulted in massive emissions reductions for the city, with savings equivalent to approximately 40 percent of all the C02 emissions from the city’s six million cars. This has tremendous implications for Sao Paulo, a densely populated, growing city.
While getting cleaner air, Sao Paulo is also making money from biogas. The carbon credits obtained from the C02 reductions are sold on the open market to countries around the world. In a perfect cycle, the profits from this recycling program are helping fund improvements to the environment in Sao Paulo. Half of the profits generated from the carbon credits are used to finance environmental remediation and urban revitalization projects in the communities surrounding the landfill. These new projects include parks designed to restore vegetation and control floods, bicycle lanes, public squares, environmental education and education programs, and even a carpentry school.
Landfills are not inexhaustible sources of energy. It is expected that by 2018 most of the available methane gas will have been extracted from the Bandeirantes landfill. However, unlike the challenges involved in finding new sources of oil, it shouldn't be difficult for Sao Paulo to find more biogas. Projects like Bandeirantes that transform environmental negatives into positives will be an important component of sustainable growth for cities worldwide in years ahead.
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