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projects:
biogas
generator
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| project
description |
In
Pabal, there are multiple power cuts
during a day. Businesses that rely on
electricity become less efficient and
lose profits as a result of power losses.
The government has no short-term plans
to address the electricity problem in
rural India so an alternative power
solution is needed to alleviate the
problems caused by power cuts.
Biogas is a reliable, cheap and sustainable
alternative to, or creator of electricity.
About fifteen years ago, there was a
government-level biogas drive, but the
government only made generators available
at a cheap rate and did not provide
proper advice and maintenance, without
which the generators were misused. The
generators relied on cow dung, which
presented an extra problem in Pabal,
Maharastra. Due to the severity of the
dry season (January - May), the local
farmers must transport the cows to a
nearby village, which has a wetter climate.
This meant that there was no cow dung
available for the generators for four
months of the year. As the generators
require 21 days start up time (where
the bacteria in the dung can build up
to a sufficient level), the generators
became hard work to use. The generators
would be non-functional for about 5
months in a year. Any farmers that did
try the generators ended up stopping
their usage. Another factor was that
farmers also wanted to use cow dung
as free fertiliser for their crops.
Because of this cow dung is not a viable
main fuel source for a biogas generator.
A
small-scale biogas generator needs
to be developed, so that it can run
on different forms of biomass and
serve a household in a localised situation.
A small generator would be the most
sustainable solution, as less power
and energy would be wasted than if
a community-based, larger generator
was designed. The localised small
biogas generator would limit any losses
from electricity and/or biogas distribution.
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| utility
of the solution |
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community can use biogas generators
to convert organic biomass into biogas.
The NGO located near to Pabal, Vigyan
Ashram, has experimented in the past
with biogas generators. They concluded
that large-scale community generators
(which are bigger than 20 m3) are not
practical, as providing service to the
whole community creates extra costs
and requires the use of more materials.
This is because the biogas or electricity
produced by the community biogas generator
must then be supplied to the community
via gas lines, electricity cables or
a compressor and canisters.
A
sustainable design would therefore
be small enough for a farmer to use
permanently as a generator and back-up
for power cuts. A design has been
developed that uses half a kilogram
of spoilt flour. The flour grains
can be black and this is a good example
of an appropriate solution. The design
of a sustainable generator should
take size into account: the biogas
generator should be designed to cater
for a typical Indian household of
6-10 people. Such a generator would
allow families to use the biogas plant
for their own individual needs and
they would be able to create biogas
in a small rear garden or even a kitchen
if the design is small enough.
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| economic
benefits / required training / major
impacts |
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An
implemented project would bring constant
electrical power to the community.
With the power cuts that are present
throughout the vast majority of rural
India, a design for a cheap biogas
generator (providing power for a family/business)
would provide a reliable power source
for much of the population. The power
cuts lead to a loss of trade for many
businesses and slow down the technological
growth of the community, causing much
of the rural population to want to
migrate into cities. A back-up power
supply would be really useful in bringing
direct economic benefit to many businesses
in Pabal.
If
a cheap design is proposed it could
be implemented in many places. This
would require a large amount of biomass,
involving the use of 'oil cake' (see
below) or crops directly from the
fields. There would be encouraged
demand in the manufacture of oil cake
and/or farming, either way potentially
increasing jobs within the area and/or
profit for those community sectors.
If a truly effective design were to
be reached, it could benefit the community
to completely replace its connection
to the electrical grid with power
generation from the community's own
biogas generator. If such a solution
can be reached then the pay back time
on the initial investment should be
deduced, as an offer for the local
community.
Other
economic benefits are also present.
Large-scale biogas generators have
the capacity to produce ethanol. If
a small-scale biogas generator is
designed and can collect a supply
of ethanol, it may have the following
benefits:
- It could be used as a fuel for gas
powered cookers or in addition to
the biogas in the generator.
- It could possibly be mixed with
used cooking oil and a form of biodiesel
can be created and then used.
- It could be then made into a fertiliser
(with the appropriate technology)
and would be very useful to the rural
population of Pabal, where the soil
has very little organic content with
in it.
The
building of trial and then commercial
biogas generator can be done at Vigyan
Ashram using local materials and skills.
The construction of such generators
can be incorporated into the curriculum,
taught to the students. The NGO could
then teach the local community how
to maintain the generators and how
to optimise them. As they are a non-profit
organisation, this would all be done
at low or no cost.
The
major impacts of implementing a biogas
generator solution to Pabal would
concern safety primarily. The generators
would need to be safe, easy to use
and easy to teach about, as any major
accidents attributed to the generator
failure would be unacceptable. The
generators would have to have a long
working life, as such a generator
would be a large investment for most
family in Pabal. Another impact of
using biomass could be that the price
of crops and 'oil cake' would increase.
This could possibly make it harder
for the community to buy food. The
'oil cake' is currently used as cattle
feed and an impact of using it in
biogas would be that farmers would
have to find another cheap source
of cattle feed.
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| description
of current local situation & resources |
| Vigyan
Ashram has experimented with the use
of other organic, cheap material in
the biogas generator. Paper (Rs. 1 /kg)
was tried, but was found to be too slow
to work when shredded and when treated
with enzymes to break down the paper.
'Oil cake', a waste product from the
peanut oil milling industry (see Optimisation
of Pabal Peanut Oil Mill Project Proposal),
(Rs. 11 - 13) was found to work well
in their generator. There are many seeds
and starch-based plants grown in the
area. For a biogas generator to be sustainable
and practical, the organic substance
used needs to be grown within a season,
otherwise the farmer/owner of the generator
would have to wait a long time (maybe
even years) before he can use the generator.
The
floating head generator has also caused
problems, as there the gas is produced
at atmospheric pressure. This means
that the supply of the gas often fluctuates
(often a person has to stand on the
floating head to get gas out). Therefore,
for a generator to be really useful
this design flaw would have to be
optimised by operating the generator
at a higher pressure or by another
method, which would give a constant
production and collection of gas that
may be used when required, i.e. when
the power cuts occur.
The
NGO's generator is 1 m3 in size and
has a 'floating dome' top to it (as
opposed to a 'fixed dome'). This means
the gas can expand and occupy extra
space in the roof. Vigyan Ashram has
also commissioned the building of
a biogas generator in a nearby village.
This is a larger scale generator (15
m3). A similar generator has been
built on a local farm and serves a
number of farms which are clustered
together. This solution works, but
an optimised solution could be created
on a smaller scale to provide for
single-family households, which are
more common.
Biogas
Generator Used at Vigyan Ashram
In
a nearby village to Pabal, a biogas
generator has used human excrement
as a power source. This option could
be researched as the design feature
of such a generator would have to
be modified. This could be linked
to the human waste disposal project
proposal.
Biogas
Generator used in a local farm
Materials:
Concrete
Sheet Steel
Used Petrol Oil Barrels
Peanut Oil Cake: Rs. 11 - 13 /kg
Pipes
Generator engines
Seeds
in Oil mill, their Marathi names and
English (given when known).
Odid
Toor
Bajri
Gawu
Kaddhanya
Methi
Carla
Maka
Rajma (kidney beans)
Black Rajma (black kidney beans)
Jawari
Chauli (black eyed peas)
Soya beans
Mohri
Puri
Howri
Herberra
Watana (peas)
Natni
Rice
Urda dal
Peanuts
Sugar
Chintsa-tam-arind
Used
oil barrels are in abundance throughout
the village
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