Waste-to-Energy

Waste-to-Energy (WTE) or energy-from-waste is the process of generating energy in the form of electricity and/or heat from the incineration of waste. In the U.S., some cities primarily in the northeastern and mid-Atlantic, burn part of their municipal solid wastes. Hemmed in by major population centers, landfill space in these areas is at a premium, so burning wastes to reduce their volume and weight makes sense. Combustion reduces the volume of material by about 90 percent and its weight by 75 percent. The heat generated by burning wastes has other uses, as well, as it can be used directly for heating, to produce steam or to generate electricity.

In 1885, the U.S. Army built the nation’s first garbage incinerator on Governor’s Island in New York City harbour. Also in 1885, Allegheny, Pennsylvania built the first municipal incinerator. As their populations increased, many cities turned to incinerators as a convenient way to dispose of wastes.

These incineration facilities usually were located within city limits because transporting garbage to distant locations was impractical. By the end of the 1930s, an estimated 700 incinerators were in use across the nation. This number declined to about 265 by 1966, due to air emissions problems and other limitations of the technology. In addition, the popularity of landfills increased.

In the early 20th century, some U.S. cities began generating electricity or steam from burning wastes. In the 1920s, Atlanta sold steam from its incinerators to the Atlanta Gas Light Company and Georgia Power Company.

Europe, however, developed waste-to-energy technologies more thoroughly, in part because these countries had less land available for landfills. After World War II, European cities further developed such facilities as they rebuilt areas ravaged by war.

The use of municipal waste combustion for energy in the U.S. is not common; the nation had only 87 such facilities in 2007 and has added several more today, while Europe has more than 430 such facilities. By the 1990s, after the tax credits extension of 1986 finally ended, fewer waste-to-energy plants were built. Figure 1 shows the generic process of converting waste to energy.