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Waste to Energy:
Electricity Generation Through Rice Husk
India
consumes around 3.4% of global energy, which makes it the world’s sixth
largest consumer of energy. The electrification rate in India is around
64.5%. However, about 35.5% of the Indian population still does not have
safe access to electricity. Therefore, there a need to search for
decentralised and renewable energy-based options to meet the rural
energy needs in a sustainable way.
 The
government has now become active in support of safe and green energy,
with specific emphasis on clean development mechanism (CDM). For this,
the Ministry of Non-Conventional Energy Sources, later renamed as the
Ministry of New and Renewable Energy (MNES), has also been set up. It
has put forward many policies for effective implementation and
utilisation of renewable energy technologies in India. Some of them are
Jawaharlal Nehru National Solar Mission of National Action Plan on
Climate Change (NAPCC), Rajiv Gandhi Grameen Vidhyutikaran Yojana (RGGVY),
National Electricity Policy (NEP), The Integrated Energy Policy of India
and the National Biogas and Manure Management Programme (NBMMP).
Renewable energy resources address the global warming and pollution
issues because they lead to the reduction in carbon emissions.
Non-renewable energy fuels, including diesel, natural gas, kerosene,
wood and coal, are expensive and lead to the pollution in the
atmosphere. Also, the continuous exploitation of these non-renewable
resources will sooner lead to their depletion. In fact, different forms
of renewable energy provide safe and sustainable access to the green
energy. Carbon emissions are also negligible with no limitation for
consumption of renewable resources. The renewable energy market in India
is pegged at US$600 million, growing at 15% per annum. The government’s
renewable energy target by 2030 is 200 Gigawatts, which is estimated to
require US$200 billion in capital investment.
The threat of global warming and climate change due to excessive use of
fossil fuels has increased the urgency of finding environmentally benign
ways of generating energy. India is blessed with an abundance of
non-depleting and environment-friendly renewable energy resources, such
as solar, wind, biomass, hydro-geothermal and cogeneration. Among all of
the renewable energy sources, biomass is in abundance, diversified and
readily exploitable resource. In India, among the renewable energy
options, bio-energy technologies have been promoted to meet the rural
electricity needs of domestic, agricultural pumping and rural industrial
(such as enterprise development) activities.
Biomass for Energy Production
The resources used for energy production should be non-conventional. The
comparison for various other resources is given below:
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Solar
energy is expensive, around Rs 400 per watt is required for its
installation;
-
Wind energy
is not available everywhere; it can be established at the place far from
birds reach and wind flow and direction is good;
-
Hydro power
plant is not feasible at all places because it requires downstream
availability of water. Also it requires high cost of establishment.
-
Energy
production through Biomass is a cheaper and easily available solution.
The establishments can be done from small communities at the village
level to large populated urban communities.
Rice
Husk Biomass Characteristics
India is the second largest producer of rice, which accounts for about
80% of the total production in the world. In 2008 the world paddy
production was 661 million tonnes and consequently 132 million tonnes of
rice husk were also produced. Rice husk is one of the alternative fuels
because of its high potential and environmental benefits. Rice is
cultivated in almost every region of India; where ample amount of water
is available. Husk is the residue left after processing rice husk in the
mills, which accounts for approximately 20% of the total rice husk
produced. Hence, a large amount of rice husk is left with no use. This
husk is either dumped and brings a waste disposal and methane emissions
problem. Moreover, the inhalation of the low density rice husk can cause
it to be air-borne easily leading to the breathing problems. However,
rice husk is a waste, but still can be used to solve many problems
related with the waste. It can be used as an additive in cement
industries, for fertilisation in the fields and also for chicken
incubation in the poultry farms. However, these methods cannot solve the
large scale of waste disposal problem. Hence, a proper utilisation of
husk for energy production can significantly resolve the problem of
waste disposal along with the energy loss. In fact the rice husk can be
converted into a useful form of energy to meet the thermal and
mechanical energy requirement for the mills themselves.
Rice husk can be converted into a useful form of energy to meet the
thermal and mechanical energy requirement of the mills itself because of
its high calorific value. Hence, the proper utilisation of husk into the
production of energy helps in minimising the waste disposal and
emissions problem.
Energy Production through Rice Husk
Conventionally, after paddy rice is processed, a huge quantity of
biomass is left as a residue in the form of rice husks. This rice husk,
when used in efficient gasification or combustion systems, has a
considerable potential to generate energy. The utilisation of rice husk
for power generation can even replace existing diesel consumption in the
rice mills for rice production. In this process of gasification, the
biomass (rice husk) is burned in control manner to produce a particular
cocktail of gases, called as the producer gas. This gas is a mixture of
carbon monoxide, nitrogen, hydrogen, carbon dioxide and a little bit of
methane. Producer gas is a combustible gas. Hence this gas is fed into a
gas engine, which drives an alternator to produce electricity. The
proper utilisation of waste into energy production has been explained by
a case study given below:
Case Study: Rice Husk Power Plant, Bihar
After paddy rice is processed, a huge quantity of biomass is left as a
residue in form of rice husks. This rice husk, when used in efficient
gasification or combustion systems, has a considerable potential to
generate energy. This successful effort has been put forward by Husk
Power Systems (HPS), a company with a goal to provide affordable,
reliable and environmentally sustainable energy to rural India. It uses
husk as the fuel to generate electricity. HPS has installed 57 plants
across 250 villages of Bihar and Uttar Pradesh. These rice husk power
plants are ‘mini power-plants’ with the installed capacity of 35-100 kW.
The HPS initiative saves 42,000 litres of kerosene and 18,000 litres of
diesel per year. About 300 kg of rice husk is used as a raw material to
generate around 40 kilowatt of energy, which is sufficient to supply
energy to 500 households for 6-12 hours per day. Generally, electricity
is supplied to domestic and commercial consumers for fixed 6-8 hours a
day. The residual waste from the plant is also used in making incense
sticks, rubber and manure. For each Megawatt of power generated, about
5,800 tonnes of carbon dioxide emission reductions can be achieved every
year.■
Development Alternatives
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