Tue, Dec 27, 2011
A project backed by the United Nations Environment
Programme (UNEP) is working to make clean
energy a reality for households in a rural
region of Pakistan.
The project coverts
agricultural waste such as wheat straw and
cotton stalks into renewable energy. UN
Photo/Eric Kanalstein
Nairobi, 27 December
2011 - Sanghar, a farming district in Sindh
province in east-central Pakistan, is home
to nearly two million people. Wheat, cotton,
sugar cane, rice and maize are grown here,
providing livelihoods and food for local
communities.
In the villages and
towns of the district, access to reliable
sources of energy is difficult. Indeed,
in households all over Sanghar, women prepare
meals and heat water by burning wood or
biomass in rudimentary stoves that release
choking, black smoke.
Further Resources
UNEP International Environment Technology
CentreNow a new project backed by the United
Nations Environment Programme (UNEP) is
working to make clean energy a reality for
local households.
Realizing that the district
was a rich source of agricultural waste,
UNEP's International Environmental Technology
Centre (IETC), based in Japan, began working
on a project to convert agricultural waste
left in the fields into clean, sustainable
energy.
As a first step, the
IETC worked with the Mehran University of
Engineering and Technology in Jamshoro to
quantify the amount of agricultural waste
in the district. A survey found that 2.5
million tonnes of waste ? wheat and canola
straw, cotton stalks, cotton gin waste,
sugarcane tops, bagasse, rice straw and
husks, and banana plant ? was produced in
the district, although not all was available
for conversion into energy.
A subsequent calculation
found that the energy potential of the available
waste was equivalent to 1.07 million tonnes
of fire wood, or 910 million units of electricity
(with a conversion efficiency rate of 20
per cent). If this energy potential was
fully realised, the converted waste could
meet the energy demands of roughly 400,000
households (at 2400 units per household).
Further research was
done to determine how agricultural waste
was managed and used, to avoid future conflicts.
For instance, it was learnt that 20 per
cent of sugarcane tops was being fed to
animals, but 80 per cent was being burnt
in the fields, along with the entire quantity
of banana plant waste and about 70-80 per
cent of rice straw. These materials could
therefore be used for energy conversion
without impacting on food supplies or other
needs.
The next step was to
decide which technology to use. Several
were considered, but after careful analysis
a biogas plant was selected, as it had the
twin benefits of being able to supply clean
fuel (biogas) to surrounding households
and produce a good supply of compost, which
could be used as fertilizer. A site was
chosen at the back of the Sanghar Sugar
Mills, which agreed to provide the land
and funds to build the plant.
Built at a cost of two
million rupees (about US$ 23,000), the biogas
plant opened on 1 August 2011. It is producing
50 cubic metres of biogas a day, using 400
kilograms a day of agriculture waste. As
well, it produces 200 kilograms a day of
liquid fertilizer and 150 kilograms a day
of solid fertilizer.
The biogas produced
is enough to provide energy to about 20
households, putting to good use a resource
that would otherwise have gone to waste.
