7/4/2008
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Biomass
As a Source of Energy
I n
many developing countries wood has been used as a fuel.
The situation is growing so desperate that wood is poached
from forest reserves. As a result the ecosystem is degrading
deplorably. So, in order to protect the natural environment,
there is every necessity of producing alternative source
of energy for the needs of the people. Biomass is the
best alternative as it is available in plenty and production
of energy from biomass is also less costly.
I. Introduction
In India, the concept of energy as "Shakti" has been at the
focus of philosphic, scientific and metaphysical thought from
time immemorial. The conventional energy sources like fossil
fuels, crude oil, natural gas etc. are dwindling fast. The
world stock of non-renewable natural sources indeed have decreased.
There is every necessity of going for renewable alternative
resources for energy. The energy crisis of 1973 left scientists
to accelerate the renewable energy programmes. The important
renewable energy sources are sun, wind, tides, waves, biomass,
hydro-power (from water) charcoal, peat, fuelwood, geothermal
energy etc. The pattern of energy consumption in India shows
that 56.5 % of total energy is from the commercial sources
like coal, oil & electricity and remaining 43.5% is non-commercial
energy. Fire wood, charcoal, agricultural residues, vegetable
wastes, cow dung, urban and industrial wastes, forest residues
are the main sources of this non-commercial energy. The most
efficient utilization of these resources comes when they are
converted to biomass by appropriate technologies. The non-commercial
biomass fuels are the main sources of energy available in
the rural areas. The 80% of our population resides in villages
are dependent on this non-commercial biomass fuels.
II. Concept of Biomass
The term biomass refers to all organic matter generated through
photosynthesis and other biological processes. The ultimate
source of this renewable biomass is the inexhaustible solar
energy which is captured by plants through photosynthesis.
It includes both terrestrial as well as aquatic matter such
as wood, herbaceous plants, algae, aquatic plants and residues,
like straw, husks, corncobs, cow dung, saw-dust, wood shavings
and other wastes like disposable garbage, night soil, sewage
solids, industrial refuse etc. In spite of all these biomass
resources available in India, they are not being properly
utilized. In fact, a large amount of it is disposed off by
burning in open fields causing serious air pollution.
In order to utilise these resources properly, biomass should
be converted to energy which can meet a sizeable percentage
of the country's demands for fuel as well as energy. Three
main approaches can be adopted for generation and proper utilization.
1. Collection of agricultural and forest residues to produce
fuels, organic manures and chemical feed stock.
2. Collection of urban and industrial wastes as fuel in boilers
and as a feedstock for producing methane and some liquid fuels.
3. Growth of some specific energy plants for use as energy
feed stock and cultivation of commercial forestry, aquatic
and marine plants for different products.
By a
number of processes, the collected wastes can be converted into
solid, liquid and gaseous fuels. The technologies include thermal,
thermo-chemical and bio-chemical conversions. The actual processes
in these technologies are combustion, pyrolysis, gasification,
alcoholic fermentation, liquefaction etc.
The main products of conversion technologies are energy (thermal,
steam, electricity), solid fuels (charcoal, combustibles) and
synthetic fuels (methanol, methane, hydrogen gas etc.). These
can be used for different purposes like cooking, lighting, heating,
water pumping, electricity generation and as industrial and
transport fuels.
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