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Biomass, in the energy production industry, refers to living and recently living biological material which can be used as fuel or for industrial production. Most commonly biomass refers to plant matter grown for use as biofuel, but also includes plant or animal matter used for production of fibres, chemicals or heat. Biomass may also include biodegradable wastes that can be burnt as fuel. It excludes organic material which has been transformed by geological processes into substances such as coal or petroleum. It is usually measured by dry weight. The term "biomass" is especially useful for plants, where some internal structures may not always be considered living tissue, such as the wood (secondary xylem) of a tree. Biofuels include bioethanol, biobutanol, biodiesel & biogas. Biodiesel and biobutanol are direct biofuels and can be used directly in petroleum engines. Biomass is grown from several plants, including switchgrass, hemp, corn, willow and sugarcane. The particular plant used is usually not very important to the end products, but it does affect the processing of the raw material. Production of biomass is a growing industry as interest in sustainable fuel sources is growing. Though biomass is a renewable fuel, it can still contribute to global warming. This happens when the natural carbon equilibrium is disturbed; for example by deforestation or urbanisation of green sites. Biomass is part of the carbon cycle. Carbon from the atmosphere is converted into biological matter by photosynthesis. On decay or combustion the carbon goes back into the atmosphere. This happens over a relatively short timescale and plant matter used as a fuel can be constantly replaced by planting for new growth. Therefore a reasonably stable level of atmospheric carbon results from its use as a fuel. Although fossil fuels have their origin in ancient biomass, they are not considered biomass by the generally accepted definition because they contain carbon that has been 'out' of the carbon cycle for a very long time. Their combustion therefore disturbs the carbon dioxide content in the atmosphere. Other uses of biomass, besides fuel:
Biomass production Biomass production for human use and consumption. Source: Whittaker R.H. & Likens G.E. "The Biosphere and Man" pp.305-328 in Leith H. & Whittaker R.H. (Eds) Primary Production of the Biosphere" Springer-Verlag Ecological Studies Vol 14 (Berlin) See also | ||||||||
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