Estimates indicate that biomass supplies six to seven percent of global energy consumption, while it remains an important energy resource in developing countries. Biomass refers to any organic material derived from plants or animals. For thousands of years wood obtained from trees was the main fuel used for human needs; thus, wood is the earliest form of biomass. Biomass can be further processed to obtain biofuels, or they can be directly burned to obtain bioenergy.
Biomass and Bioenergy
Biomass is a substance derived from living organisms, wood being the most common example. Besides wood, biomass includes crops, farm wastes, plant oils, animal wastes, and some kinds of garbage. By burning biomass, the energy stored can be converted into heat, electricity, or mechanical energy. Using biomass to generate energy is called biopower or bioenergy.
Types of Biofuels
Biofuels are produced in three different forms: solid, liquid, and gas.
- Solid biofuels are organic matter consumed through burning: examples include animal manure or dung, bagasse, charcoal, garbage, wood, straw, dried plants, and grain shells.
- Liquid biofuels are generally obtained from plant matter: examples include biodiesel – diesel derived from vegetable oil or animal fats – and alcohol fuels such as ethanol obtained from corn or grain.
- Biogas given off by decaying plants, animals, and manure constitutes the gaseous form of biofuels. The main component in biogas is methane, which is also a basic constituent of natural gas.
Benefits and Applications of Bioenergy
While fossil fuels take millions of years for their formation, biomass is renewable: plants grow continuously, animals continuously produce manure and humans throw away wastes on daily basis. Thus, biomass cannot be depleted as it is being produced at the scale it is being consumed. Unlike solar or wind energy, bioenergy is available whenever needed.
Combustion of biomass adds carbon dioxide into the atmosphere and burning of municipal solid wastes releases toxic materials that can seep into soil and water supplies. However, biofuels do not contain sulfur and hence do not contribute to acid precipitations. Further, in the long-term purview, the resultant raise in carbon emission levels is less significant, as they are the product of recent photosynthesis.
An additional benefit linked with biofuels is that they can be obtained and utilized locally, thus making individual areas self-sufficient and less reliant upon foreign energy suppliers. They have the potential to replace fossil fuels in car engines, district heating units, as well as in electricity generation plants. Biomass can provide electricity for farms, industries, and remote villages.
Future of Bioenergy
Since biomass is automatically replenished, some energy experts envisage it as among leading potential alternatives for future generations, while others underscore the associated practical limitations. Extensive research is required to find cleaner and more efficient ways to produce biofuels in future. Scientists are investigating the possibility of using biofuels to generate hydrogen for fuel cells. Gasification of solid biofuels – conversion into natural gas – is also under consideration.
Sources:
2006, Schlager and Weisblatt, Alternative Energy, Thomson Gale.
2011, Heinrich, Ann, Sustaining Earth’s Energy Resources, Marshal Cavendish Corporation.
2003, Biomass Fuel, Environmental Encyclopedia, Thomson Gale.
Zeeshan Amin - I am a professional mechanical engineer with a diverse experience of over 5 years with Honda Cars, Shell Oil and Nestle.
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