Waste-to-Energy - Generating Electricty From Garbage
Waste-to-energy (WtE) or energy-from-waste (EfW) is the process of creating energy in the form of electricity or heat from the incineration of garbage. WtE is a form of energy recovery. Most WtE processes produce electricity directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels.
Burning trash, or incineration, is without a doubt one of the oldest, and simplest methods used by humans to dispose of their waste. Environmental concerns over the past several decades borne from fears of toxic gases and cancer-causing substances being released into the air we breathe resulted in a significant reduction in the number of operating facilities which dispose of trash in this manner. But new research by the Environmental Protection Agency (EPA) is suggesting that burning trash may cause less environmental harm than putting it in landfills. Really!
So What Has Changed?
Modern technology, for one. The incinerators of today are capable of not only eliminating the waste, but to also provide a source of electricity while accomplishing their initial task in a cleaner manner. The heat created through incineration is used to boil water, which creates steam, which in turn generates electricity.
The EPA report entitled "Is it Better to Burn or Bury Waste for Clean Energy Generation" compares two options for generating electricity from municipal solid waste (MSW). The first method is the waste-to-energy process and the second is landfill gas-to-energy (the collection of landfill gas, or methane, created from the anaerobic decomposition of the MSW in the landfill). The landfill gas is then combusted in a turbine or engine and used to generate electricity. The report provides significant detail on the study and the full results are available on the American Chemical Society Website. The conclusion is that the waste-to-energy method is superior over gas-to-energy as far as reduction in greenhouse gases (35% less), as well as a more efficient method (by a factor of 10) of producing electricity as a byproduct. Most importantly, it recommends that waste-to-energy methods should be considered as an option under U.S. renewable energy policies.
Wast to Energy Statistics
Approximately 13% of garbage in the United States is disposed of through incineration -- far less than the 54% buried in landfills and the 33% that is recycled. There are currently 87 waste-to-energy plants actively producing in the U.S., located predominately in Florida, New York and Minnesota. But this could change if the trash incineration gets official endorsement from lawmakers as a "renewable" source of power, and there is currently legislation in Congress that proposes to do exactly that.
Given the results of the EPA study, and the pending legislation, it sounds like we will need to stay tuned for further development in the waste-to-energy arena. In the meantime, as concern about climate change continues to grow, any renewable source of energy - even a pile of garbage - seems appealing.