The chemical energy stored in plants and animals (that eat plants or other animals), or the waste they produce is called bioenergy. During conversion processes such as burning biomass releases its energy in the form of heat and produce carbon dioxide that comes to replace the carbon dioxide absorbed while the plant grew. In general it could be noted that the use of biomass for energy production is the reverse process of photosynthesis.
The energy drawn from biomass is a form of renewable energy. The use of this energy to recycle carbon and does not burden the environment with carbon dioxide, unlike fossil fuels. Of all the renewables, biomass has a unique capacity, is essentially a form of stored solar energy. Moreover, there is the possibility of processing of biomass and conversion of solid, liquid and gaseous fuels.
Biomass resources that can be used for energy production cover a wide range of materials. Biomass can be divided into two categories:
• Traditional biomass is generally limited in developing countries and uses a small scale. Includes firewood and charcoal for domestic use, rice chaff, and other plant residues and animal dung.
• Modern biomass usually involves large scale use to replace conventional sources of fossil fuels. Includes dry twigs from the forest and agricultural residues, municipal waste, biogas and biofuels from energy crops (such as oils from plants and / or plants containing starch and sugars).
Bioenergy Applications
The applications of bioenergy is extremely diverse and include among others the provision of heating, electricity generation and vehicle fuels. Biomass can be used directly (eg burning wood for heating and cooking) or indirectly if the change into a liquid or gaseous fuel (eg ethanol from sugar beet or biogas from animal waste).
The traditional biomass used in open fires for cooking and heating is still very important in developing countries because of lack of alternatives. Burning wood in small systems such as wood stoves or open chimneys for heating has a long tradition. Wastes from wood processing to form clusters of biomass (pellets) or softwood chips (chips) are now used in innovative heating systems.
Modern biomass used to produce energy and heat at large facilities. Solid biomass such as wood waste, yard waste and straw can be used for combustion in a specially constructed power stations, or with coal in existing plants using coal as fuel. Biogas can be exported to specific sites from agricultural waste, such as The sparse mud.
Environmental impact
Biomass in all its applications (power generation, heating fuel) contributes significantly to environmental protection and conservation of natural resources, whether used or waste specific crops. However, bioenergy is likely to lead to some adverse environmental effects such as oxynisi (acidification), water eutrophication and smog. The production of crops for energy and this can have negative impacts due to conventional farming methods used.
However, we must see these effects in relation to the benefits for the environment and natural resources. The use of biogas, which processes gas from anaerobic digestion and landfill gas for power generation has great benefit not only for our climate, but also for farmers who can improve the quality of the sludge and reduce odors .
Globally, biomass is used a lot for traditional heat, often in unsustainable ways. Its use for energy production is comparatively very less. Only about 18.4 GW installed worldwide in OECD countries in 2000, representing about 1% of the total potential energy.
The potential biomass energy is enormous. Globally, biomass could yield 9% of global primary energy and 24% of its energy needs by 2020. The use of biomass systems, combined heat and power is the most efficient solution.