Nodepage

Biogas

Poo power: cow dung can be used as fuel

With fuel wood becoming increasingly expensive and also scarce in some areas, there is a need to look for alternative cooking fuel. Cow manure and biogas fuel technology provides a free, sustainable source of power all year round – and a useful fertiliser which helps to provide a better income for farmers.

Cow dung is mixed with water and placed into fermentation pits where it is broken down by natural bacteria, releasing methane. The gas is collected and stored in a tank and then piped on demand to the farmer’s house, to be burnt to generate energy for cooking, laundry and lighting.

The biogas plants also produce a rich organic waste which is dried and used as fertiliser. Both fertiliser and fuel wood are increasingly expensive in the country and biogas has a potentially important future. It may also be used to manage organic waste in urban settings.

Above, a cross-section of a fixed-dome digester. For further information on how this works, and for other types of biogas digester, see the Practical Answers technical briefs on biogas.

Practical Action is helping farmers in Sri Lanka install biogas units on their farmers to convert cow dung into an alternative power supply.

Extra energy from biogas

Cooking on biogasSakunthaladev Kathiravetpillai is 31 years old and lives with her husband and four children in Vattavaan, a rural district of Sri Lanka. The family income comes from the sale of milk from their cows. Each day Sakunthaldev and her daughters used to spend several hours collecting wood for cooking and heating water.

Practical Action were able to help the family by showing them how the waste from their cows could provide them with all the energy they need. The construction of a biogas plant at their home has transformed their lives. The plant produces methane gas from animal dung by adding water to the waste and letting it ferment. This gas produced can then be used to provide energy for cooking and lighting.

Sakunthaladev, freed from the daily drudgery of firewood collection, now has more time to spend on activities that generate income for the family. Also the organic waste from the plant improves the productivity of their vegetable garden.

Sakunthaladev’s husband has become skilled at installing and maintaining the biogas plant, making him crucial for the development of other plants in the area. In order to help make biogas a more widely used fuel Practical Action is also now working on setting standards for biogas systems in Sri Lanka.

Mr Ratnayake and biogas

Ten years ago almost half of Sri Lanka's energy consumption was biomass. The biomass most commonly utilised was wood, used mainly by poorer, rural inhabitants, for household cooking.

For farmers like Mr. HP Ratnayake this reliance on biomass fuels could have made a hard life even more difficult. The fuel wood he and his family relied on was becoming increasingly scarce and expensive. This was mainly due to the destruction of the forests as a result of the intensive farming practices being employed to meet the demand for food. Mr Ratnayake desperately needed an alternative, appropriate energy source to replace his costly existing one.

Practical Action helped farmers like Mr Ratnayake to install biogas units on their farms to utilise the waste from their cows and obtain a free power supply. Now, with nothing more than cow muck Mr Ratnayake produces enough power to cook with, iron the laundry and provide heat and light his home without using a single piece of wood. The biogas technology he requires to do this is wonderfully simple.

First Mr Ratnayake's collects manure from his cows in a specially adapted cattle shed where they feed; he then mixes it with water and leaves it to ferment in a large concrete tank or pit.

Gas (of which 65% is methane) is produced as a by-product of this fermentation and Mr Ratnayake collects it in a simple storage tank (manometer) from where he can then pipe it into his house when he needs it.

One added bonus of using a biogas unit is that women and children, freed from fuel collection, the cleaning of smoke-blackened utensils and the disposal of animal waste, have gained around two hours a day which they can now employ elsewhere.

Around 80% now use this time for various income generating activities, which currently accounts for approximately 24% of their monthly income.

The other great benefit of using a renewable power source like biogas for Mr Ratnayake and his family is that there is very little waste from the process and it is environmentally friendly.

The dried manure left after the 'biogas' process is even richer than ordinary muck and makes a fantastic organic fertiliser for Mr Ratnayake's crops - which he can then sell at a higher price as 'organic crops'.

So now, thanks to cow manure and biogas technology, Mr Ratnayake and his family not only have free, sustainable power all year round - but a better income as a result.

Fritz Schumacher, author of Small is Beautiful and Practical Action’s founder said: “There is no substitute for energy. The whole edifice of modern life is built upon it. Although energy can be bought and sold like any other commodity, it is not just a commodity, but the precondition of all commodities, a basic factor equally with air, water and earth.”

With your help, Practical Action can improve people’s lives by providing them with access to energy for now and for the future. If you can, please make a donation using the button. You really will make a difference.

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You can download  technical briefs and manuals on biogas at Practical Answers, the technical information service of Practical Action, or you can submit an enquiry to the Practical Action staff via the online form

Biogas Technology and Integrated Development - Experiences from Sri Lanka

Practical Action South Asia's energy work

National Standards for Biogas Sri Lanka 2006
A workshop to propagate biogas national standards for wider uptake.

Lanka Bio Gas Association

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PDF

Biofuels for transport

Massive and unregulated large-scale production of biofuels would be potentially destructive for the environment, a threat to food security, and will affect sustainable development and the livelihoods of the poor.

  • English,
  • policy
PDF

Biofuels for transport

Massive and unregulated large-scale production of biofuels would be potentially destructive for the environment, a threat to food security, and will affect sustainable development and the livelihoods of the poor.

  • English,
  • policy
PDF

Biogas

  • fact sheet
  • English

Biogas is an organic fuel used for cooking and lighting purpose in domestic use that has been made from dung and other organic waste.

Liz Bates, Published by Practical Action on 03/02/07

PDF

Biogas Digest - Volume I Biogas Basics

  • guides and manuals
  • English

Manual describes the basics of producing and using Biogas from dung and organic waste materials.

Werner Kossmann, Uta Pönitz, Published by GTZ - Deutsche Gesellschaft fr Technische Zusammenarbeit on 12/20/11

PDF

Biogas Digest - Volume II Application and Product Development

  • guides and manuals
  • English

Important factors, providing a checklist for the planning and procedure for product development of a biogas plant.

Warner Kossmann et al., Published by GTZ - Deutsche Gesellschaft fr Technische Zusammenarbeit on 02/21/12

PDF

Biogas Plants in Animal Husbandry

  • guides and manuals
  • English

Guide addressing the planners and providers of stock-farming and agricultural-extension services in developing countries.

Uli Werner / Ulrich Stöhr/ Nicolai Hees, Published by GTZ - Deutsche Gesellschaft fr Technische Zusammenarbeit on 02/21/12

PDF

Biogas Promotion in Kenya

  • guides and manuals
  • English

A review of experience with a detail factors that have influenced the adoption of biogas in Kenya.

Stephen Gitonga, Published by Practical Action Eastern Africa on 01/01/97

PDF

Biogas technology and integrated development: experiences from Sri Lanka

Traditionally the biogas technology was looked at as a source of energy for the rural population mainly for lighting, though it possessed several other benefits. The Practical Action South Asia project recognised the need to look at the biogas technology in an integrated manner to reap the...

  • English,
  • project
PDF

Biogas Use in Reconstruction

  • fact sheet
  • English

Biogas technology can provide essential energy services in a post-disaster context.

Martin Bounds, Published by Practical Action on 04/25/12

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Comments

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  • Reply

    David Otieno said:

    said:
    Sincerely fuel wood has become expensive and scarce say here in Uganda, getting fire wood and charcoal is not easy for most the tree have been destroyed. So I would like to urge people with animals to resort to biogas since it can be easily produced at home even if you have a small piece of land
    on 7/7/11
    • Reply

      Ajith Sugathan said:

      said:
      You call to this no.-08907841001
      on 15/7/11
  • Reply

    Ubaid said:

    said:
    Can we generate electricity using common electricity generator by biogas?
    on 9/7/11
    • Reply

      Muwonge Edward said:

      said:
      Yes we can get electricity from bio gas by using bio gas generator.
      on 19/4/12
      • Reply

        www.facebook.com/Better.Energy.Polska said:

        said:
        www.better-energy.pl
        on 17/10/13
  • Reply

    Aminu Bishir said:

    said:
    I lives in Nigeria and we don`t have enough electricity that is our main problem. We have a lot of biogas but most of don`t know how to benefit from it. So please i want some one to help me on how to convert it into elecricity easily, Thank you.
    on 9/7/11
  • Reply

    Neil Noble at Practical Action said:

    said:
    Biogas can be used to generate electricity with a combustion engine generator where it would replace petrol or diesel. Biogas can be sued directly in petrol engines, using the Otto cycle, where spark plugs are used to ignite the fuel and in modified diesel engine in which biogas is introduced into the cylinder with the air supply. A small amount of diesel is required to ignite the mixture in these duel fuel engines. Another option is to adapt a diesel engine to an Otto cycle by replacing the diesel injector with a spark plug. There are also some duel fuel generator sets on the market that are specifically aimed at biogas use, mostly from India and China.
    on 13/7/11
    • Reply

      Amos Nguru - www.afrisolenergy.com said:

      said:
      I am in touch with Chinese companies that make gas generators. I have also witnessed quite a number of engines being run by bio gas to generate electricity raging from small farm engine to 150 Kva factory generator.
      on 9/11/11
  • Reply

    tom millar said:

    said:
    I live in the uk and am interested in setting up a biogas digester using cow dung converting to electricity for a rural tractor shed and have a couple of small scale beef farmers who are also interested in the possibilities. With gas and electricity prices rising as they are it would seem folly to ignore what obviously works in other less well-off countries. Are there any plans with dimensions for the various designs indian/chinese etc.. or do you know of any people within the uk or other places who have set up small scale biogas generation and could steer me in the right direction?
    on 14/7/11
    • Reply

      Neil Noble at Practical Action said:

      dgibbs said:
      Biogas technology is used in the UK mainly in farming and in sewage treatment plants. There is an information portal http://www.biogas-info.co.uk/ that provides a list of companies and organisations involved in the technology as well as some details about funding options.
      on 18/7/11

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