Biogas

‘No longer will we have to inhale smoke. All we have to do is light a match and the gas stove is on, which is so good for us’ – Sita, villager in Terai Region, Nepal

What is Biogas?

Biogas is a methane rich combustible gas produced by anaerobic digestion of organic substrates such as manure, sewage sludge, agricultural wastes and others. The gas produced as a result can be collected and hence burned as a fuel for cooking and lighting purpose. Importantly, biogas is an environmental friendly and sustainable technology with low carbon footprint.

Where is it appropriate?

Biogas plants are appropriate in developing countries where the penetration of commercial energy sources is nominal, people still have to depend upon traditional energy to fulfil most of their energy needs. Biogas technology is an appropriate technology because it is affordable, acceptable and easily available to buy the technology. A biogas plant supplies the energy and fertilizer.  The reduction in chemical fertilizers due to use of slurry, reduction in the consumption of fuelwood and kerosene for cooking and lighting, and improve in health and hygiene are the main benefits from biogas plant.   Biogas plants are also appropriate in urban and semi urban area to generate energy from municipal solid waste.

Why is it innovative?

  • Biogas reduces the dependency of people on inefficient and expensive fuel sources such as fuelwood, dung cake, kerosene etc. The use of these traditional energy sources cause emission of harmful substances in case of incomplete combustion.
  • Biogas is a clean energy coming out from the anaerobic digestion of agriculture residue, organic waste, animal manure etc. It helps to reduce the greenhouse gases emission thus contribution towards environmental protection.
  • Biogas helps to reduce the indoor pollution due to kitchen smoke and reduce the incidence of illness caused by smoke.
  • Biogas can be used at household and industrial purposes and the energy contained in the biogas can be transformed into various forms of energy such as: electricity, heat, light, mechanical etc.
  • We can build new toilet facilities and link them to biogas digesters, which improves sanitation whilst allowing even human waste to become useful.
  • The local communities have a double advantage through purchase of livestock such as cows, buffaloes. It supports continuous feed to the digester and helps increase in income through sell of milk, meat and other by-products.
  • The digested slurry produced in the process of biogas formation can be used as excellent organic manure in the field, thus increasing the crop yield.

Biogas_plant_sketch

Testimonial
‘In the morning, buffalo milk can be sold to the dairy farm, so we get money. The fertiliser that comes from the biogas plant will be used to grow vegetables. We are so pleased to get so many benefits from the project!’ – Sita, villager in Terai Region, Nepal

Where have we used it?

We have installed biogas digesters in marginalised, rural communities in Nepal. The installations were accompanied with Micro-Enterprise training courses which gave community members advice on how to profit from their new energy source. They have since made the biogas their own, using it to set up tea stalls, dairy farms and candle making businesses, among others.

Kapilvastu and Sindhupalchowk Districts

‘We get more wood when the river floods, we get one or two loads per day, it’s risky, sometimes the river washes people away….We can’t wait until it is ready. We are working together for biogas’. – Sarasuti Sunar, villager in Nepal

The collection of wood is dangerous, and burning it is too as smoke damages people’s lungs and eyes. So we have installed community owned biogas plants in the Kapilvastu and Sindhupalchowk Districts of Nepal, providing communities with a clean source of heat and light.

The biogas plants have also prompted the villagers to start their own businesses, including candle making and poultry and dairy farming. Two residents from very different social backgrounds, Mr. Lekhnath Subedi and Miss Kalpana Nepali, have teamed up together to start a fruit processing business. In the caste system prevalent in India and Nepal, Leknath is considered to be of the high status Brahmin caste, while Kaplana is considered to be an ‘untouchable’. Untouchables are groups traditionally thought to be unclean and unfit for interaction with members of other castes, and they are often extremely poor. Yet in this case, these traditional differences have been overcome as Leknath and Kaplana have teamed up, using biogas to boil the lapsi fruit into delicious candies and jellies.

How does it work?

Biogas digesters come in many different sizes and forms, but they all rely on one basic principle: the breakdown of organic materials by microorganisms. The organic materials are sealed in a large digester, and left there for microorganisms to feed on. While feeding, the microorganisms emit methane gas and carbon dioxide as waste. The resulting mix of gases can then be collected and burned as fuel.

(Picture Sources: Stills from the BBC lifeline appeal for Renewable World)

(Information on how biogas works taken from biogas.info.co.uk. I have paraphrased, not copied)

Our innovative Biogas Bag-digester is proudly supported by The World Bank

World-Bank-Logo

 

Bibliography

NNFCC, What is AD? [online] Available at here [Accessed 11th December 2014]

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