An alternative to landfilling municipal solid waste is incinerating it, whichgreatly reduces the volume that remains to be landfilled. Humankind has along history of burning its waste. As recently as 1960, almost a third of U.S. municipal solid waste was incinerated. The incinerators of 1960, of course, given the times, did not recapture energy and polluted at will. Increasing concern for this air pollution and the possible toxicity of the incinerator ash discouraged incineration in the 1960s and 1970s, but the dramatic fossil fuel price rises of the 1970s and fears of landfill price rises in the 1980s once again encouraged incineration-but a new kind of incineration, where the waste was converted not only to ash but also to energy (Ujihara and Gough 1989; Curlee et al. 1994; U.S. EPA 1995b). By the 1990s, this waste-to-energy incineration had stabilized at about 15% of U.S. MSW. All biomass incineration generates only about 3% of U.S. electricity output (DOE 1998b).