U.S. Department of Energy - Energy Efficiency and Renewable Energy
Tribal Energy Program
Biomass Energy Resources
Biomass is organic material from either plants or animals. There are two potential sources of biomass material:
The most economical sources of biomass for energy uses are residue streams emanating from commercial biomass processing, since turning waste into energy is often the best way to dispose of it. With this in mind, the best way to assess your tribe's biomass energy resources is to examine the activities (both current and planned) taking place on or near your tribal lands and consider what organic waste streams are produced. Some typical examples include:
Animal manure from farms, cattle feed lots, and swine and poultry facilities can be converted into methane using anaerobic digestion, a process that has gained considerable interest in recent years, primarily from dairy farms. Methane is the main component of natural gas, and can be converted into electricity using simple engine-driven generators. Good information on anaerobic digestion for dairy waste can be found in the Environmental Energy Company's Dairy Waste Anaerobic Digestion Handbook.
For animal rendering facilities, a new technology shows promise for converting animal byproducts into energy. A new plant in Carthage, Missouri, developed by Changing World Technologies, Inc., is using a high-temperature and high-pressure process to convert turkey processing byproducts into a liquid fuel that is similar to crude oil. Animal fats can also be converted into biodiesel.
Agricultural and food processing residue
Agricultural residues such as stalks, leaves, corncobs, and other residues can potentially be converted into ethanol via fermentation or into a liquid fuel called BioOil via a high-temperature process, although both processes are just now being commercialized by Canadian companies Iogen and Dynamotive. Likewise, Changing World Technologies, Inc., which is currently using animal byproducts to produce a liquid fuel equivalent to crude oil, claims the process would also work for agricultural residues, although that has not been publicly demonstrated. Investigators are also examining the use of anaerobic digesters to convert agricultural residues into methane, which can be used like natural gas.
Agricultural and food processing residues may also serve as a fuel source for use in direct combustion or gasification, particularly if they have a high fat content. For instance, an olive oil mill in Spain is currently turning its olive residue into a cake-like material that is used as a fuel. See the press release from GE Energy, which is assisting with the project. Fatty residues such as tuna cannery sludge can also be converted into methane—an energy source much like natural gas—using an anaerobic digestion process.
Forestry and Lumber
Forestry and lumber operations produce wood residues that can either be burned in a conventional biomass power plant or can be fed into a gasifier to produce a biogas, which can be converted into heat and power, or even biofuels, bioproducts, or hydrogen. In the West, an increasing emphasis on forest thinning is generating low-quality wood residue, which could provide a suitable input stream for a small biomass power plant. Information on the latest developments in biomass gasifiers can be found at the National Renewable Energy Laboratory's biomass research website.
Advanced technologies are able to convert wood residues into ethanol via fermentation, or into a liquid fuel called BioOil via a high-temperature process. Both processes are just now being commercialized by Canadian companies Iogen and Dynamotive. Ethanol is used as a transportation fuel, and BioOil is used as a substitute for fuel oil.
Landfill methane capture
Landfills generate methane, a pollutant and a powerful greenhouse gas, through anaerobic digestion, and most landfills are now required to collect their methane emissions. Although many landfills dispose of the methane by flaring it off, a growing number of landfills have begun putting the methane to use as an energy source. The landfill methane can be converted into electricity onsite using such technologies as reciprocating engines, microturbines, or fuel cells, or it can be piped to a nearby factory, where it can be used as a source of both heat and power.
Municipal solid waste (MSW), also known as trash: Trash can be burned as an energy source, or can be gasified. Technologies under development promise to convert MSW into ethanol. In addition, Changing World Technologies, Inc., which is currently using animal byproducts to produce a liquid fuel equivalent to crude oil, claims the process would also work for trash, although that has not been publicly demonstrated.
Some trash collectors are allowing their customers to separate out high-value residue streams such as leaves and other yard trimmings as well as waste wood from building construction and demolition. Both of these residue streams could be converted to energy using the processes available for forestry and lumber. Likewise, organic residue streams could be converted to energy in the same ways as agricultural residues.
Pulp and Paper Production
Pulp and paper production generates sawdust and bark that can be converted to energy using the same methods as used for forestry and lumber. A major energy source is black liquor, a residue stream from the pulping process, which is typically burned in boilers to produce heat and power. Black liquor can also be gasified to produce power more efficiently, with lower emissions. See the U.S. Forest Products Industry website.
Corn is probably the largest energy crop grown in the United States. Corn is mainly converted into ethanol, but it is also used as a fuel source for stoves. In addition, cornstarch is serving as the basis for a new industry that produces plastics from natural resources instead of petroleum. Both DuPont and Cargill Dow LLC have developed processes to convert cornstarch into polymers. See the article from the October 8, 2003 edition of the EERE Network News.
Soybeans are probably the second largest energy crop in the United States. Soybeans are mainly converted into biodiesel, although soybean oil also serves as the basis for a wide variety of bioproducts, notably soybean-based inks.
Other multiuse crops
Additional crops that can serve as energy sources include sorghum, oats, barley, wheat, cotton, rice, oilseed crops, sugar cane, and others. All of these crops could serve as a carbohydrate source for either fuels or bio-based products, and could also be gasified or exposed to a high-pressure, high-temperature pyrolysis process to produce liquid and gaseous fuels. In Colorado, Blue Sun Biodiesel is using a government grant to investigate biodiesel production from mustard-based oilseed crops and other oilseed crops could also be used for this purpose. In Japan, Toyota is planning to use sugarcane as a source of carbohydrates to produce bio-based plastics, and it is currently heavily used as a source of ethanol in Brazil.
Trees and grasses
Switchgrass, hybrid poplar, willow, and bamboo are some of the quick-growing trees and grasses that may serve as the fuel source for a biomass power plant. Although no biomass power plant in the United States currently draws on dedicated energy crops, JEA in Jacksonville, Florida, is currently under contract with the Biomass Investment Group to buy power from a proposed 70-megawatt biomass power plant fueled with a grass that resembles bamboo. These fuel sources can also be gasified, and then converted into power, biofuels, bioproducts, or even hydrogen.
Trees and grasses are considered "woody" biomass because of the high amount of lignins, a glue-like binder, present in their structures, which are largely composed of cellulose. Such so-called "lignocellulose" biomass sources can potentially be converted into ethanol via fermentation or into a liquid fuel called BioOil via a high-temperature process, although both processes are just now being commercialized by Canadian companies Iogen and Dynamotive. The recovered lignins could also be used to produce bio-based chemicals and products.