Biomass

BioMass

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Biomass or Bioenergy refers to the use of organic material to produce energy.

Biomass

Definition

Biomass refers to the organic material that is used for production of energy. This energy production process is referred to as Bioenergy.  Biomass is primarily found in the form of living or recently living plants and biological wastes from industrial and home use. Due to the breadth of the term, the physical composition of biomass is inconsistent, but generally includes carbon, water and organic volatiles.

 
 

For the production of energy from biomass, the term feedstock is used to refer to whatever type of organic material will be used to produce a form of energy.  The feedstock must then be converted to a usable energy form through one of many processes. 

Feedstock + Process -> Usable Energy Form

Some common biomass conversion processes include:

  • Combustion: the process by which flammable materials are burned in the presence of air or oxygen to release heat. It is the simplest method by which biomass can be used for energy. In its rudimentary form, combustion is used for space heating (i.e. a fire for warmth) but can also be used to heat steam for electricity generation[1]Biomass Energy Centre.(BEC). Combustion. February 2015 http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17502&_dad=portal&_schema=PORTABiomass Energy Centre.(BEC). Combustion. February 2015 http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17502&_dad=portal&_schema=PORTABiomass Energy Centre.(BEC). Combustion. February 2015 http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17502&_dad=portal&_schema=PORTA.
  • Gasification: is the conversion of biomass into a combustible gas mixture referred to as Producer Gas (CO+H2+CH4) or Syngas. The gasification process uses heat, pressure and partial combustion to create syngas, which can then be used in place of natural gas[2]Aboriginal Ankur Corporation (AAC). What is Biomass Gasification? February 2015 http://aboriginalankur.com/category/what-is-biomass-gasification/ Aboriginal Ankur Corporation (AAC). What is Biomass Gasification? February 2015 http://aboriginalankur.com/category/what-is-biomass-gasification/ Aboriginal Ankur Corporation (AAC). What is Biomass Gasification? February 2015 http://aboriginalankur.com/category/what-is-biomass-gasification/ .
  • Pyrolysis: Consists of thermal decomposition in the absence of oxygen. It is the precursor to gasification, and takes place as part of both gasification and combustion[3]Biomass Energy Centre.(BEC). Pyrolysis. February 2015http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17506&_dad=portal&_schema=PORTAL Biomass Energy Centre.(BEC). Pyrolysis. February 2015http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17506&_dad=portal&_schema=PORTAL . The products of pyrolysis include gas, liquid and a sold char, with the proportions of each depending upon the parameters of the process.
  • Anaerobic digestion (or biodigestion): is the process whereby bacteria break down organic material in the absence of air, yielding a biogas containing methane and a solid residue. The methane can then be captured to produce energy. Similarily, the solid residue can also be burned to produce energy.
  • Fermentation: involves the conversion of a plant’s glucose (or carbohydrate) into an alcohol or acid. Yeast or bacteria are added to the biomass material, which feed on the sugars to produce ethanol (an alcohol) and carbon dioxide. The ethanol is distilled and dehydrated to obtain a higher concentration of alcohol to achieve the required purity for the use as automotive fuel. The solid residue from the fermentation process can be used as cattle-feed and in the case of sugar cane can be used as a fuel for boilers or for subsequent gasification.

Some feedstocks are more conducive for certain biomass conversion processes than others. The determination of which feedstocks and processes will be used is determined largely by the availability of resources and the desired end form of energy

Context

Prior to the industrial revolution, biomass was the primary source of energy. Biomass now makes up only a small percentage of total world energy use. However, for approximately 2.5 billion people, it remains the primary source of energy for cooking and heating[4].   The use of biomass is highly contextual to the region in which it is used – availability of resources, availability of technology and economic viability are all drivers of biomass use. 

Some jurisdictions - especially those with sustainable forestry initiatives - have declared biomass a "carbon neutral" energy source. This is based upon the logic that carbon emissions from burning biomass will be recaptured by the plants grown to feed biomass reactors in the future, thus forming a carbon cycle for the plant[5]Vieira da Rosa, A. (2013). Fundamentals of Renewable Energy Processes (3rd ed.). Oxford, UK: Academic Press. Vieira da Rosa, A. (2013). Fundamentals of Renewable Energy Processes (3rd ed.). Oxford, UK: Academic Press. .

The environmental benefits and costs are highly contextual depending on the technology and feedstocks used.  While some biomass processes such as waste-to-energy are touted for their lower CO2 emissions, some processes, such as combustion, release carbon dioxide and particulate matter that is a significant concern for human health.

The world's most energy-poor peoples and regions still rely on biomass for the majority of their energy needs[4]Bridge, G., & le Billon, P. (2013) Oil. Cambridge, UK: Polity Press. Bridge, G., & le Billon, P. (2013) Oil. Cambridge, UK: Polity Press. . The lack of appropriate ventilation mechanisms for burning biomass is a major health concern and contributes to short life expectancies in much of the developing world.

Concerns associated with biomass go beyond human health. Depending upon the source of biomass used, deforestation, cropland degradation (due to diverting agricultural residues), and land use alteration can all be relevant issues associated with biomass.

References

  1. ^ Biomass Energy Centre.(BEC). Combustion. February 2015 http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17502&_dad=portal&_schema=PORTA
  2. ^ Aboriginal Ankur Corporation (AAC). What is Biomass Gasification? February 2015 http://aboriginalankur.com/category/what-is-biomass-gasification/ 
  3. ^ Biomass Energy Centre.(BEC). Pyrolysis. February 2015http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,17506&_dad=portal&_schema=PORTAL 
  4. a, b Bridge, G., & le Billon, P. (2013) Oil. Cambridge, UK: Polity Press. 
  5. ^ Vieira da Rosa, A. (2013). Fundamentals of Renewable Energy Processes (3rd ed.). Oxford, UK: Academic Press. 

Take a Step Back

Alternative Energy

Alternative Energy is a term used to refer to any source of energy that is not derived from fossil fuels.

Renewable Energy

Energy sources that are not depleted when used or are naturally replenished within a human lifetime.

Keep Learning! Progress To

Pyrolysis

Pyrolysis is the process of heating organic material at high temperatures in the absence of oxygen.

Gasification

Gasification is a process that converts organic or fossil fuel based material into syngas and carbon dioxide.

Waste to Energy

Waste to Energy (WTE), is a term that is used to describe various technologies that convert non-recyclable waste into usable forms of energy including, heat, fuels and electricity.