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Domestic biogas in asia1
- 1. Domestic Biogas in Asia Dr David Fulford CEnv MEI www.kingdombio.com davidf@kingdombio.com
- 2. What is biogas? • Anaerobic Digestion (AD) breaks down wet biomass to gas and compost • Relies on microbes (bacteria and archaea) in animal dung • Several possible applications • Talk focuses on biogas in rural areas for domestic uses, with dung as feed
- 3. Background • SNV (Netherlands Development Organisation) Asia Biogas programme - focus on rural domestic biogas fed by animal dung. • Started in Nepal (1993) - extended to Vietnam, Bangladesh, Cambodia and Laos • Based on previous programme set up Development and Consulting Services of United Mission to Nepal (1976 to 1984)
- 4. Technology • Dung mixed with water and allowed to flow into underground pit lined with masonry • Plants built for individual households • Need 3 to 6 cows or 6 to 12 pigs • Gas piped to kitchen for cooking • Slurry from plant collected • Can be used as a fertilizer after some processing • Removes smell
- 5. Benefits (1) • Clean gaseous cooking fuel • No smoke • Instant availability • Does not need constant attention • Reduced danger of burns • Resource (dung) available from animal sheds • No need to walk to collect firewood
- 6. Benefits (2) • Cooking pots easy to clean (no soot) • Saving of time (3 hours a day) • Saving of firewood (2,000 kg a year) • Reduced deforestation (1,000 biogas plants saves 33.8 ha forest from clear felling) • Much reduced smell from the animal sheds (in Vietnam, pig sties are close to the house)
- 7. Benefits (3) • Biogas can be used for lights • Reduced smell from kerosene lamps • Savings of 32 litres kerosene a year • Reduced risk of house fires • Saving of carbon (4,900 kg a year) • Since gas available in the morning, children get cooked breakfast before school.
- 8. Benefits (4) • A latrine can be attached • Improved sanitation • Reduced transfer of pathogens (especially if slurry is properly processed) • Reduced risk to women (who go out at dawn or dusk to use the fields) • Reduce incidence of snake bites
- 9. Benefits (5) • Slurry is a good quality compost (better than raw dung) • Liquid slurry should be absorbed in dry biomass and composted for 1 month • Compost even better if use vermi-culture • Growers prepared to pay cash for vermi- compost
- 10. Economics • With so many benefits, what is drawback? • Cost - most cost:benefit analyses show financial benefit as marginal • BUT high value for “externalities” - e.g. saving forests, health benefits etc. • Biogas becomes attractive with subsidy • SNV Asia Biogas Programme offered reliable subsidy
- 11. Asia Biogas Programme • Involve people at all levels, from government policy makers to masons who build plants • Promotion, Education and Training • Emphasis on quality of technology • Use a local design, but ensure it works well • Train staff to check quality of construction • Release subsidy for each plant only when it meets specification
- 12. Tasks involved in running a biogas programme Construction Quality Training Management Household Micro Credit, Marketing & Sales Biogas SME Development Sector R&D Subsidy Extra services Ref: Dagmar Zwebe, “SNV Renewable Energy Developments: The Biogas Programme for Animal Husbandry Sector of Vietnam”, Presentation (May 2012).
- 13. Project Achievements Start Built in Built by Invest Country Year 2011 2011 Cost $ Nepal 1992 19,246 250,476 663 Vietnam 2003 23,372 123,714 621 Cambodia 2006 4,826 20,756 488 Bangladesh 2006 5,049 14,972 430 Laos 2007 439 2,405 448 Total 52,932 412,323 Based on: Brief progress and planning report the Working Group on Domestic Biogas under the Energy for All Partnership as per May 2012
- 14. Starting a Programme • Find a group interested in biogas to manage programme (or set up a group) • Involve people from government and encourage renewable energy policy • Design a subsidy & micro-finance scheme • Develop a local design that works well • Use local companies to build plants • Train staff regularly
- 15. Subsidy Issues (1) • Who funds externalities? i.e. • Who pays to save forests, improve people’s health, reduce carbon emissions? • National governments - but other priorities • International Community • Bilateral Aid (SNV, KfW, DANIDA, USAID etc) • UN agencies: World Bank, ADB, UNDP, UNEP, UNFCCC • Danger of corruption
- 16. Subsidy Issues (2) • WWF puts high value on certain habitats: e.g. tiger ranges - pay extra • CDM designed to fund carbon offsets - CER certified emissions reductions • Also VER - voluntary emissions reductions • Carbon offset trading under voluntary market mechanisms (Big companies want to look “Green”) • Complex - large nos. needed
- 17. Carbon Offset Biogas • New Charitable Company established • Foundation SKG Sangha - based on biogas programme in South India • Aim: to use voluntary carbon offset finance to encourage biogas projects elsewhere • Also interest in other renewable energy projects • First project in Egypt funded by UNDP
- 18. Thank you
- 19. Technical Aspects • Underground dome made from masonry (bricks or concrete) • Gas stored by displacing slurry into reservoir tank • Volume 4 m3 (2 m3 to 10 m3)
- 21. Thank you
- 22. Other applications (1) • Sewage Treatment • KIST project in Rwanda processing sewage from prisons (10,000 people) • Saves 50% of wood fuel for cooking • Volume 100 m3 x 10 = 1,000 m3
- 23. Other applications (2) • Urban biogas to process food wastes • Volume 1 m3, food waste gives more gas • Family’s own food waste saves 25% LPG • Use extra food waste from local shops • Can use sewage in addition
- 24. Other applications (3) • Local authority wastes • Market wastes • Office canteen wastes • Municipal solid wastes • Food processing wastes
- 25. Thank you
Hinweis der Redaktion
- Best example of a biogas plant is a cow. Breaks down biomass (grass) into energy and a waste product. Cattle dung is a good source of the right microbes. Anaerobic = without oxygen. Archaea so old that oxygen in the atmosphere is an innovation to which they have not adapted. If they are in an oxygen environment, they shut down and wait for it to go away. Work best in places such as the guts of animals or in marshes.
- SNV did not like me telling them that their project was based on work in which I was previously involved. Many of the ideas which they claim that they developed were actually already used in the previous project. Ideas developed by an American – Sanfred Ruohoniemi, who used to work for USAID. “ What have you done to ‘my’ project?” UMN passed the project to ADB/N (Agricultural Development Bank of Nepal) who had UNDP funding (1985 to 1992). SNV “rescued” the project and made it work more effectively.
- Designs based on the Chinese fixed dome design (more later, if people are interested). Most of the plant is underground. See feed pit, the gas pipe and the slurry pit. A Canadian builder, Nick Peters, adapted the Chinese design for Nepal. SNV used this design, but changed it to make it easier to construct (GGC 2047).
- Extra income seen in Vietnam comes mainly from the family being able to keep piglets for longer to allow them to fatten up. Previously, they tended to sell the piglets while they were still small because they could not stand the smell!
- In “Katcha” houses in India (built of woven bamboo with thatched roofs), people keep their valuables in a bag by the door. If the house catches fire (which happens too often), they can grab them as they run out of the door.
- Change of cultural attitudes. Survey in 1991, old people said they did not use the latrine, preferred to use the fields. Younger people, when interviewed on their own, admitted they used the latrine at night, when the old people were in bed. This old couple were very proud of their latrine as well as their biogas plant.
- Slurry fresh from the plant is not as good as a fertilizer – contains hydrogen sulphide, needs to be “matured”. Using dry biomass (e.g. straw) to soak up the slurry means that nitrogen is conserved, not allowed to evaporate. Composting means that the dry biomass acts as a sponge and retains the fertilizer in the top layer of the soil.
- Many arguments about subsidy. However, need to cover “externalities”. Use of carbon offset finance less of a concern for development philosophers. Users are paid for a “service” – that of saving carbon.
- Numbers in other places: China - 42.8 million plants by end 2011; India – 4.4 million by April 2011 under National Biogas and Manure Management Programme (NBMMP). (Enenrgy4all report, downloaded from HEDON website).
- Building viable domestic biogas programmes, published by SNV, Oct 2009 available from SNV publications web site.
- Sewage plant in a prison in Cyangugu, Rwanda, near the Congo border.