This article was updated on the 11th September 2019.
Biomass is defined as any organic material produced by the growth of microorganisms, plants or animals, and it can be converted into usable forms of energy.
Biomass is an attractive petroleum alternative because it is a renewable resource which is distributed more evenly over the earth's surface than oil or coal, which are finite energy sources. Biomass can also be harnessed using more environmentally friendly technologies than those used when drilling for oil or mining for coal.
In the United States, resources of biomass include residues from the agriculture and forestry sectors, industrial wastes, municipal solid wastes, and terrestrial and aquatic crops grown solely for energy purposes. Residues from agriculture and forestry (especially from paper mills) are the most common biomass resources used for the generation of electricity and power.
Biomass resources, including all plants and plant-derived materials, are essentially energy that was originally captured by photosynthesis. This means biomass is a fully renewable resource and biomass-derived fuels, power, chemicals, materials, or other products can theoretically generate no net greenhouse gas. The production and consumption of biomass is also generally domestic, so it has substantial security, economic and environmental benefits.
What are Biofuels?
Fuels which are derived from biomass are referred to as biofuels. Agricultural products specifically grown to convert their biomass into biofuels include corn and soybeans. Currently, research is being carried out to improve the conversion of non-food-based, perennial crops, like switchgrass and a variety of woody crops, as well as agricultural waste and algae, into biofuels.
Biofuels are manufactured from biomass through thermal, chemical, biochemical or electrochemical processes. Examples of biofuels used today include ethanol and biodiesel.
Using biofuels reduces greenhouse gas emissions, the buildup of toxic air particles, and dependence on imported oil, while simultaneously supporting agriculture and rural economies.
Biofuels contain oxygen so, unlike gasoline and diesel, the addition of biofuels to petroleum products allows the fuel to combust more completely. This reduces air pollution by reducing the amount of wasted fuel released into the atmosphere. When fossil fuels are burned, carbon dioxide that was captured by plants and fossilized over millions of years is released and contributes to global warming. On the other hand, when biofuels are burned, the carbon dioxide they release is balanced by the carbon dioxide captured by photosynthesis during the recent growth of the plant materials from which they are made.
What is Ethanol?
The most widely used biofuel in today’s world is ethanol. Ethanol is also referred to as ethyl alcohol or grain alcohol. Ethanol is converted from sugars and starch found in plants using thermal processes. Ethanol can be blended with gasoline in varying quantities to reduce the consumption of petroleum fuels, as well as to reduce air pollution. Ethanol is also increasingly used as an oxygenate additive for standard gasoline. Ethanol is used as a replacement for methyl t-butyl ether (MTBE), which is responsible for groundwater and soil contamination.
What is Biodiesel?
Biodiesel is a clean-burning alternative fuel to petroleum diesel. Biodiesel is produced from domestic, renewable resources such as new and used vegetable oils and animal fats. Biodiesel is primarily produced through base-catalyzed transesterification, a biochemical process. Biodiesel is simple to use, biodegradable, non-toxic, and essentially free of sulfur and aromatics.
What is Biopower?
Biomass power, or biopower, is the use of biomass to generate electricity, or heat and steam required for the operation of a refinery. Biopower technologies include direct-firing, cofiring, gasification, pyrolysis and anaerobic digestion.
Most biopower plants use direct-fired systems. Biopower plants burn biomass feedstocks directly to produce steam. This steam drives a turbine, which turns a generator that converts the power into electricity. In some biomass industries, the spent steam from the power plant is also used for manufacturing processes or to heat buildings. Paper mills, the largest current producers of biomass power, generate electricity or process heat as part of the process for recovering pulping chemicals.