Biomass types are woody biomass, solid waste-based biomass, ethanol, biogas, and biodiesel. Biomass examples include poultry litter, sawdust wood chips, and plant residue.
The types of biomass are discussed in this article, from different perspectives. For each of these perspectives, a brief explanation as well as examples are given, as outlined below;
Types of Biomass Based on Source
As the subheading implies, biomass can be categorized into different types, based on some distinctive factors. One of such factors is the source (means of derivation) of biomass.
Types of biomass based on where it is derived from include;
1). Forest-derived Biomass
The primary and most common source of biomass is forests.
It is also true that the growing importance of biomass as a source of renewable energy has led to a heightened interest in forestry and conservation of natural forests by both the public and private sectors.
Basically, managed forest reservations are made up of well-ordered vegetation (trees and/or other plants) of different ages, which provide a sustainable supply of biomass that is harvested at various times of the year .
By maintaining a balanced, continuous cycle of planting and harvesting in such managed forests, the emissions of carbon dioxide into the atmosphere can be minimized or brought to a neutral point.
Natural forests still play a major role as biomass producers, although the current rate of deforestation has led to a decline in the output of natural forests. Nearly 50 percent of wood-based bioenergy generation can be attributed to forests.
Aside direct harvest of forest resources, biomass can be obtained from the by-products of forestry such as wood chips. These are referred to as forest residue or forest waste, and include dead wood, logging residue, and low-quality or imperfect, commercial timber which must be removed from forests to reduce crowding and the risk of fires.
Forest residue refers mainly to biomass which is not removed or harvested from forests after logging, or the material which is produced during forest management operations like thinning .
In order to produce substantial amounts of bioenergy, large expanses of forest are usually required. The demand in terms of land and biomass varies on the basis of factors like age and species of trees, as well as nature and accessibility of the forest terrain.
This implies that the use of forest biomass requires intensive development and management of sustainable forest resources.
2). Agriculture-derived Biomass
This includes all forms of organic matter derived directly or indirectly from agriculture and agricultural crops.
Examples of agricultural crops from which significant biomass can be derived include herbaceous crops like giant reed. Sugarcane, wheat, sorghum and maize are all starchy agricultural sources of biomass from which liquid biofuel (ethanol) can be derived. Other examples include livestock waste and agricultural residue.
Poultry litter is an example of agricultural residue, as well as a good example of agriculture-derived biomass. It usually comprises of straw, wood shavings, or shredded paper, and bird droppings. Aside being used as fertilizer, poultry litter can be used in bioenergy generation .
Cattle and pig farming, as well as fishery, can also produce usable biomass in the form of animal waste. Agricultural residue may be in the form of remnants from harvest, including unusable crop parts, and low-quality produce. These materials can serve as a significant source of biomass fuel .
3). Industry-derived Biomass
This type of biomass can also be referred to as industrial biomass. It includes all forms of organic matter derived (directly or indirectly) from industrial processes.
A good example of industrial biomass is mill residue. This is a by-product of the industrial processing of wood, and is equivalent to solid biomass fuel, such as that which is derived from forests. Mill residue can be burnt in a waste-to-energy plant to generate heat (bioenergy) which is used to drive a steam turbine, among other possible applications.
Wood pellets is yet another example of industry-derived biomass. It is comprised of wood (including bark, wood shavings, saw dust, and wood chips) which has been refined industrially into uniform-sized, cylindrical pellets. The advantages of wood pellets include the fact that it is more durable than most other forms of solid biomass, and has a relatively low moisture content  which makes it more efficient as a fuel.
Other examples of industrial biomass include fibrous waste from paper mills.
4). Waste-derived Biomass
While many other types of biomass are essentially (and indirectly) derived as by-products or waste materials, this type of biomass is directly gotten from waste.
Organic municipal solid waste (MSW) is a classic example of waste-derived biomass. It comprises of all organic matter that is derived from residential or commercial properties. Predictably, such biomass includes materials like paper, food waste, organic yard waste and kitchen waste.
The use of this kind of waste to produce bioenergy is a favorable move for the environment. This is because the organic fraction of municipal waste is generally about 70 percent of the entire waste volume, and has a moisture content of between 85 and 90 percent . When left to decompose in landfills and other waste disposal facilities or sites, these materials typically release greenhouse gases and other contaminants that contaminate the environment.
Sewage is another example of waste-derived biomass. It is fairly similar to livestock (agricultural) waste and can be used in the generation of bioenergy through pyrolysis, drying and incineration, or anaerobic digestion.
Types of Biomass based on Energy-Generation
Another basis of classification of biomass is the generation of energy. This classification identifies the various types of biomass fuel, as follows;
5). Woody Biomass
As the name implies, this includes all forms of biomass fuel derived from wood material.
Examples include wood waste derived from mills in the form of sawdust, and wood chips; forest residue including wood debris and other by-products of forest management; agricultural residue, and urban wood waste.
Asides industrial and forest wood by-products, agricultural crops like switchgrass and corn also serve as sources of woody biomass.
Biogas refers to gaseous fuel derived from biomass. This type of biomass is therefore a derivative of other types.
Biogas typically comprises of methane alongside small amounts of other gases. It is commonly produced when biomass undergoes decomposition (called anaerobic digestion) by microorganisms . The raw material for producing biogas may be any of diverse options, ranging from municipal waste in landfills (landfill gas) to sewage.
Commercially, biogas is produced by the anaerobic decomposition of biomass. It is an economical and renewable fuel, and is believed to have minimal environmental impact.
7). Solid Waste-based Biomass
Equivalent to organic municipal solid waste, this type of biomass includes all discarded organic matter that can be burnt to generate heat (bioenergy).
Solid waste-based biomass may be used directly as fuel, without having to subject it to anaerobic digestion so as to derive biogas. The practice of burning organic solid waste (in waste-to-energy plants) serves as a method of effective disposal, while producing usable energy.
However, this practice may release greenhouse gases into the atmosphere, and is therefore not the best environmental option.
8). Alcohol-based Biomass
Like biogas, this type of biomass is simply a derivative of other types.
Ethanol is the most common example in this category. It is produced from (mainly) plant biomass through the process of fermentation, which is a form of anaerobic decomposition.
The use of ethanol as fuel has been practiced for more than a century. It became notable however, when it became one of the options for powering automobile engines in the twentieth century .
Although ethanol is renewable, its use as a biofuel has been hampered by the fact that it is relatively expensive to produce. Conventional engines will also require some form of modification to enable then run effectively on ethanol.
This is another derivative type of biomass. Biodiesel is produced from the chemical reaction between lipids and alcohols; a process called transesterification.
Biodiesel provides a renewable alternative to fossil fuels. However, it is usually blended with petroleum-diesel before it can be used in diesel engines.
Biomass can be distinguished into categories based on different factors. Two of such factors include the Source of biomass, and the Energy-Generating Capacity of biomass.
Agriculture-derived biomass includes all organic matter derived from the practice of agriculture. Examples of this type are crop residue (woody and fibrous matter), and animal waste.
Industry-derived biomass includes organic matter derived from various sectors of industry. Examples are organic residue and waste from mills and industrially-produced wood pellets.
Forest-derived biomass is often the product of forest management practices, and may occur in the form of forest waste and forest residue.
Waste-derived biomass refers to the organic content of discarded waste material, which usually comprises of yard waste, kitchen waste and food waste.
Based on energy-generation, biomass can be distinguished into woody biomass, solid waste-based biomass, ethanol, biogas, and biodiesel. These materials each serve as potential sources of energy, and have the advantage of being renewable.
1). Albanna, M. (2013). “Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste.” Management of Microbial Resources in the Environment (pp.313-340). Available at: https://doi.org/10.1007/978-94-007-5931-2_12. (Accessed 29 January 2022).
2). Bettinger, P.; Boston, K.; Siry, J.; Grebner, D. L. (2017). “Estimation and Projection of Stand and Forest Conditions.” in Forest Management and Planning (Second Edition) pp. 87-111. Available at: https://doi.org/1016/B978-0-12-809476-1.00004-7. (Accessed 29 January 2022).
3). Carolan, M. S. (2009). “A Sociological Look at Biofuels: Ethanol in the Early Decades of the Twentieth Century and Lessons for Today.” Rural Sociology 74(1):86 – 112. Available at: https://doi.org/10.1526/003601109787524034. (Accessed 29 January 2022).
4). EPA (2021). “Basic Information about Anaerobic Digestion (AD).” Available at: https://www.epa.gov/anaerobic-digestion/basic-information-about-anaerobic-digestion-ad. (Accessed 29 January 2022).
5). Mikeska, M.; Nasjer, J.; Peer, V.; Frantik, J.; Kielar, J. (2019). “Quality assessment of gas produced from different types of biomass pellets in gasification process.” Available at: https://doi.org/10.1177/0144598719875272. (Accessed 29 January 2022).
6). Mohammed, I. N.; Kabbashi, N.; and Alade, A. (2018). “Significance of Agricultural Residues in Sustainable Biofuel Development.” Available at: https://doi.org/10.5772/intechopen.78374. (Accessed 29 January 2022).
7). Peretti, I. (2019). “Chicken Manure to Megawatts.” Available at: http://biomassmagazine.com/articles/16429/chicken-manure-to-megawatts. (Accessed 29 January 2022).
8). Titus, B. D.; Brown, K.; Helmisaari, H.; Vanguelova, E.; Stupak, I.; Evans, A.; Clarke, N.; Guidi, C.; Bruckman, V. J.; Iveta, V.; Armolaitis, K.; De Vries, W.; Kaarakka, L.; Hogg, K.; and Reece, P. (2021). “Sustainable forest biomass: a review of current residue harvesting guidelines.” Energy, Sustainability and Society volume 11. Available at: https://energsustainsoc.biomedcentral.com/articles/10.1186/s13705-021-00281-w. (Accessed 29 January 2022).