I. INTRODUCTION

Up to the mid-1990s, only a few commercial virgin biomass energy systems in which dedicated biomass is grown for use as an energy resource were in operation in industrialized countries. The technology is available or under development and is slowly being incorporated into regional, national, and world energy markets. More rapid deployment awaits the inevitable effects on renewable energy usage of fossil fuel depletion and environmental issues. Most of the contribution of biomass to primary energy demand in the 1990s comes from waste biomass. Waste biomass is energy-containing materials that are discarded or disposed of and that are mainly derived from or have their origin in virgin biomass. They are lower in cost than virgin biomass and often have negative costs. Some are quite abundant, and some can be disposed of in a manner that provides economic benefits to reduce disposal costs. Waste bio­mass is generated by anthropological activities and some natural events. It includes municipal solid waste (urban refuse); municipal biosolids (sewage); wood wastes and related residues produced in the forests and logging and forestry operations; agricultural wastes such as animal manures and crop resi­dues produced in farming, ranching, and related operations; and the wastes produced by certain industries such as the pulp and paper industry and those involved with processing foodstuffs. In this chapter, the production of these wastes and their energy potential and availabilities are addressed. The United States is used as the model country because U. S. data are available on most waste biomass to illustrate its role in the development of biomass energy on a national basis. But the conclusions regarding waste biomass as an energy resource in the United States are generally similar for other industrialized coun­tries.