American garbage-disposal giant, Waste Management, has partnered with InEnTec, an Oregon-based company, to begin commercializing
a plasma-gasification process which converts garbage into energy.

Plasma gasification technology has been in development and pilot testing for decades. Major pilot plants, capable of processing 1,000 tonnes or more of garbage daily, are under development in Florida, Louisiana and California.

In theory, the process is simple. Torches pass an electric current through a gas (often ordinary air) in a chamber to create a superheated plasma with a temperature above 7,000 degrees Celsius. The plasma’s tremendous heat dissociates the molecular bonds of any garbage placed inside the chamber, converting organic compounds into syngas (a combination of carbon monoxide and hydrogen) and trapping everything else in an inert vitreous solid, called slag. The syngas can be used as fuel in a turbine to generate electricity. It can also be used to create ethanol, methanol and biodiesel. The slag can be processed into materials suitable for use in construction.

In practice, gasification has been unable to compete economically with traditional municipal waste processing. But the cost has been coming down, while energy prices have been going up.

According to Louis Circeo, director of Plasma Research at the Georgia Tech Research Institute “the curves are finally crossing—it’s becoming cheaper to take the trash to a plasma plant than it is to dump it in a land fill. … The EPA has estimated that if all the municipal solid waste in the U.S. were processed with plasma to make electricity, we could produce between 5 and 8 percent of our total electrical needs—equivalent to about 25 nuclear power plants or all of our current hydropower output.”

Use of syngas to generate electricity does produce carbon dioxide but much less than using fossil fuels. According to Louis Circeo “For every ton of trash you process with plasma, you reduce the amount of CO2 going into the atmosphere by about two tons.”

(From sources including Scientific American)