Biomass resources that are used directly as a fuel, or converted to another form or energy product that are available on a renewable basis are commonly referred to as feedstocks.
Biomass feedstocks include dedicated energy crops, agricultural crops, forestry residues, algae, biomass processing residues, municipal waste, and animal waste.
Dedicated Energy Crops
Dedicated energy crops are non-food crops that can be grown on marginal land specifically to provide biomass. These break down into two general categories. Herbaceous 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 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 Residues
Agriculture 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.
Forestry 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. Examples include tree tops, limbs, and other woody material.
There are a variety of aquatic biomass resources, such as algae, giant kelp, other seaweed, and marine microflora. Algae are a diverse group of primarily aquatic organisms, often fast growing and able to live in freshwater, seawater, or damp oils. They may be unicellular and microscopic or very large, as in the giant kelps. Certain algae produce hydrogen and oxygen, while others manufacture hydrocarbons and other products.
Biomass Processing Residues
Biomass processing yields byproducts and waste streams that are collectively called residues and have significant energy potential. For example, the processing of wood for products or pulp produces unused sawdust, bark, branches, and leaves/needles. These residues can then be burned for heat and energy, or converted into additional bioproducts. Because these residues are already collected at the point of processing, they can be convenient and relatively inexpensive sources of biomass for energy.
Any organic matter, including sewage, industrial, and commercial wastes, from municipal waste collection systems. Plant-derived organic material makes up a significant fraction of residential, commercial, and institutional post-consumer waste. However, municipal waste does not include agricultural and wood wastes or residues.
Animal wastes from farms and animal-processing operations are a complex mixture of organic materials that can pollute the environment if left unprocessed. Through biochemical conversion processes like anaerobic digestion, these wastes can be used to make many products, including energy.
Biomass Resources Map
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.
This map shows the distribution of biomass resources across the United States, by county. Each shade shows the amount of biomass available in thousands of metric tons per year. If you have trouble accessing this information because of a disability, please contact the Webmaster.