The process of energy generation from municipal solid waste is done through the process of incineration in combined heat and power plants or in landfills. The first U.S. incinerator was built in 1885 on Governors Island in New York and, as at 2018, the number of waste-to-energy facilities in the United States stood at 75.
Municipal solid waste usually consists of biomass materials like paper, wood, cardboard, leather products, food scraps, grass and leaves from yard trimmings. It can also be made up of non-biomass combustible materials like plastics and other synthetic materials derived from petroleum. In 2017, about 334 trillion British thermal units of energy were derived from biomass energy consumption in the United States. Paper and paperboard are the highest selected materials generated from the municipal waste stream in the United States. A number of new and emerging technologies also exist that are able to generate energy from waste but without the need for direct combustion. These include the use of thermal technologies, like gasification or non-thermal ones, like fermentation.