Biomass ResourcesBiomass resources include any plant-derived organic matter that is available on a renewable basis. These materials are commonly referred to as feedstocks.
Biomass FeedstocksBiomass feedstocks include dedicated energy crops, agricultural crops, forestry residues, aquatic crops, biomass processing residues, municipal waste, and animal waste.
Dedicated energy cropsHerbaceous energy crops are perennials that are harvested annually after taking 2 to 3 years to reach full productivity. These include such grasses as switchgrass, miscanthus (also known as elephant grass or e-grass), bamboo, sweet sorghum, tall fescue, kochia, wheatgrass, and others.
Short-rotation woody crops are fast-growing hardwood trees that are harvested within 5 to 8 years of planting. These include hybrid poplar, hybrid willow, silver maple, eastern cottonwood, green ash, black walnut, sweetgum, and sycamore.
Agricultural CropsAgricultural crops include currently available commodity products such as cornstarch and corn oil, soybean oil and meal, wheat starch, and vegetable oils. They generally yield sugars, oils, and extractives, although they can also be used to produce plastics as well as other chemicals and products.
Agriculture Crop ResiduesAgriculture crop residues include biomass materials, primarily stalks and leaves, that are not harvested or removed from fields in commercial use. Examples include corn stover (stalks, leaves, husks, and cobs), wheat straw, and rice straw. With approximately 80 million acres of corn planted annually, corn stover is expected to become a major feedstock for biopower applications.
Forestry ResiduesForestry residues include biomass not harvested or removed from logging sites in commercial hardwood and softwood stands as well as material resulting from forest management operations such as pre-commercial thinning and removal of dead and dying trees.
Aquatic CropsThere are a variety of aquatic biomass resources, such as algae, giant kelp, other seaweed, and marine microflora.
Biomass Processing ResiduesBiomass processing yields byproducts and waste streams that are collectively called residues and have significant energy potential. Residues are simple to use because they have already been collected. For example, the processing of wood for products or pulp produces unused sawdust, bark, branches, and leaves/needles.
Municipal WasteResidential, commercial, and institutional post-consumer waste contains a significant proportion of plant-derived organic material that constitute a renewable energy resource. Waste paper, cardboard, wood waste, and yard waste are examples of biomass resources in municipal waste.
Animal WasteFarms and animal-processing operations create animal wastes that constitute a complex source of organic materials with environmental consequences. These wastes can be used to make many products, including energy.
Some biomass feedstocks, such as municipal waste, are found throughout the United States. Others, such as energy crops, are concentrated in the eastern half of the country. As technologies develop to more efficiently process complex feedstocks, the biomass resource base will expand.