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Report 3 (of 5):
Where There's Muck - Germany
Introduction
Biogas is produced by the action of
bacteria on organic material in airless conditions
which is why the process is also known as anaerobic
digestion. The bacteria slowly digest the material
(usually animal dung, human wastes and crop residues)
and produce a gas which is roughly 60% methane and
40% carbon dioxide.
Biogas is a well established fuel
for cooking and lighting in a number of developing
countries. Biogas makes a meaningful contribution
to the energy supply and it saves fossil energy,
such as coal, oil and gas. It also makes a significant
ecological contribution to heat and electricity production.
Biogas is an environmentally friendly
source of energy because it produces electricity
and heat but still keeps carbon dioxide emissions
neutral and emits no sulphur. As fossil based fuels
become scarcer and more expensive and carbon dioxide
emission levels become of greater concern, the benefits
and potential of biogas as a source of energy supply
are being increasingly recognised.
Biogas as a Renewable Source
of Energy
In the area of Soltau, about eighty
kilometres south of Hamburg, in Germany, twenty farms
are now using animal excrements as a renewable source
of energy. The farmers use nature to keep the system
in balance. Each farmer has their own biogas plant
which works independently of the other farms and
operate effectively as decentralised energy systems.
The farmers use the heat that is generated
from the biogas to warm their homes, the farm buildings
and the stables, as well as for hot water. In the
summer time, the heat is used to dry the harvest.
The electricity generated is used in the home, for
example, for cooking and lighting, and on the farm,
for milking etc.
Biogas Technology
Farmer Dieter Prenzler fuels his farm
and buildings by using biogas. The gas is generated
from the bodily waste of twelve hundred pigs, four
thousand hens and the waste from the farmer’s
own family. There is sufficient gas produced to heat,
light and power the farmhouse and its outbuildings
in all but the coldest weather or busiest periods.
The animal excrement needed to make
biogas is washed into the system through a false
floor by gravity and the pig’s urine. The droppings
and urine from the pigs fall into the space below
the floor, flow into the hole and then into the septic
tank.
Other ingredients can also be added,
such as the hen droppings, waste from the farmhouse
lavatory and straw from the stables which adds body
to the concoction. Waste fats are brought in from
the restaurants in Hamburg and they produce twenty
times more gas than the excrement from the pigs.
The other benefit is that Farmer Prenzle is paid
for using the waste.
The animal excrements are transformed
in the septic tank by micro-organisms which produce
methane gas and a high quality, low smell fertiliser.
The methane gas powers a standard car engine to create
the heat and electricity for the farm and its buildings.
So far, only Ford and Opel engines have been used
because they have the necessary metallic composition
to cope with the sulphur released by the gas. The
car engine needs regular maintenance and servicing
and the whole system takes up to an hour a day to
maintain.
After the farm and its buildings have
been heated by the biogas, and the cooking etc. has
been completed, there is still some power left over
which the farmers sell to the electricity companies.
Fertiliser
As well as creating their own electricity
and their own heating, the farmers produce a high
quality fertiliser which does not smell. The biologically
recycled materials are carried to the fields and
deliver high value nutrients to plants and crops
which suit their growth.
The left over sludge keeps its nutrients
for the crops but with the gas removed, the fertiliser
does not smell. The sludge is a valuable by-product
and because it has lost its potent smell, it does
not have to be dug into the earth like conventional
sludge. Instead, it can be sprayed directly onto
the crops. The other advantage is that the sludge
can be spread at any time of the year.
Energy From Natural Resources
The advantage of biogas energy is
that it is an effective form of power supply which
is created from natural and renewable resources.
On the farms, there is a natural cycle which the
farmers use to produce biogas. Plants and crops grow
in the fields on the farm. Pigs, cows and other farm
animals feed from the fields and create dung. The
combination of the animal excrement with plant residue
is passed into a septic tank and converted by the
biogas plant into methane gas and sludge. The methane
gas generates the power to heat and provide electricity
for the farmhouse and the buildings. The by-product
is a rich sludge full of nutrients which can be laid
in the fields as a fertiliser to help the plants
and crops to grow.
For further information, please contact:
Hans-Hermann
Jacobs,
Ilhorn 1,
29643 Neuenkirchen,
GERMANY.
Tel: +49 5195 9870
Fax: +49 5195 9871 |
Heinrich
Weseloh,
Vahlzen 10,
29643 Neuenkirchen,
GERMANY.
Tel: +49 5195 2582
Fax: +49 5195 2570 |
Further reading available from
ITDG Development Bookshop
Biogas Promotion in Kenya: A review of experiences
Stephen Gitonga
£5.95 1997 pb (IT Kenya) ISBN 996696066X
A Chinese Biogas Manual: Popularising technology
in the countryside
Edited by Ariane van Buren
Uses diagrams and pictures to show how the basic design of the biogas pit can
be adapted for construction in different soils, from sandstone to sheer rock,
which should encourage other developing countries to embark on their own biogas
programmes. Reprinted in 1997.
£8.95 1979 136pp pb (ITP) ISBN 0903031655
Running a Biogas Programme: A handbook
David Fulford
Describes the designs and uses of biogas plants, with technical appendices,
for domestic and community plants. Likely economic and social effects of biogas
programmes are described from experience, and advice given in the problems
of management.
£14.95 1988 188pp pb (ITP) ISBN 0946688494
To order any
of these books from ITDG Development Bookshop,
send a Sterling Cheque (adding 15% for postage
and packing to European addresses, 25% elsewhere),
or credit card details (American Express,
Visa or MasterCard) to:
ITDG Development Bookshop
103-105 Southampton Row, London WC1B 4HH,United
Kingdom.
Tel + 44 171 436 9761 Fax + 44 171 436
2013 Email orders@itpubs.org.uk
or visit our website at http://www.developmentbookshop.com/ |
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