USES OF BIOGAS

Biogas has a wide variety of applications. It can be used directly for cooking and lighting, or for heat generation, and for electricity production and fuel for cars.

Studies in China have shown that when it is used to heat and light greenhouses it boosts carbon dioxide levels, boosting photosynthesis by increasing the carbon dioxide concentration, which boosts photosynthesis in the greenhouse plants and increase yields.

Experiments in Shanxi Province have shown that increasing carbon dioxide four-fold between 6 am and 8 am boosts yields by nearly 70 percent. A biogas lamp gives both light and warmth to silkworm eggs, increasing their rate of hatching as well as cocooning over the usual coal heating.

At industrial level, the methane and carbon dioxide mix in biogas can be used to inhibit picked fruit from ripening too early as it inhibits metabolism, thereby reducing the formation of ethylene in fruits and grains. It also kills harmful insects, mould, and bacteria that cause diseases (Kangmin, L. & Ho, M-W)

Table 1 shows some typical applications and for one cubic metre of biogas. Small-scale biogas digesters usually provide fuel for domestic lighting and cooking.

Table 1: Some biogas equivalents Download the full PDF version to see this table.
Social impacts of using biogas
•Biogas is a clean fuel, thus reducing the levels of indoor air pollution, a major cause of ill-health for those living in poverty
•Lighting is a major social asset, and already there are estimated to be over 10 million households with lighting from biogas (Martinot, 2003). Improved lighting is associated with longer periods for work or study
•Where biogas is substituted for woodfuel, there are two benefits: a reduction in the pressures on the forest, and a time-saving for those who have to collect wood – usually women and children
•If a biogas plant is linked to latrines in a sanitation programme, it is a positive way of reducing pathogens and converting the waste into safe fertilizer
•Where biogas is linked with sales of the resultant fertilizer, it is an excellent source of additional income
•Fertilizer can be used on crops to increase their yield
•In China and India biogas plants are produced in great numbers by local artisans. In Kenya, where biogas technology is still in its early stages of dissemination, local manufacturers have been quick to realise the potential and get involved with the production of biogas plants.
•Biogas can be used to generate electricity, bringing with it the possibilities of improved communications; telephone, computer, radio and television for remote communities
•Fuel produced locally is not so vulnerable to disruption as, for example, grid electricity or imported bottled gas
References and resources
•Using a Biogas DigesterPractical Action Technical Brief
•Rural Energy Services: A handbook for sustainable energy development Anderson, T., Doig, A., Rees, D. and Khennas, S., ITDG Publishing, 1999.
•A Chinese Biogas Manual. Ariane VanBuren (editor), ISBN: 9780903031653 (0903031655), ITDG Publishing (UK), 1979
•ARTI Biogas Plant: A compact digester for producing biogas from food wasteARTI [Accessed February 2007]
•India's bright green idea: compressed biogas for cars Biopact [Accessed February 2007]
•Electricity in Households and Microenterprises Clancy Joy, Rebedy Lucy: ISBN: 9781853395017. ITDG Publishing (UK), 2000
•Running A Biogas Programme: A Handbook Fulford David, ISBN: 9780946688494 ITDG Publishing (UK), 1988
•Technical–economical analysis of the Saveh biogas power plant Giti Taleghani,G.& Akbar Shabani Kia, A.S. Renewable Energy, Vol 30, Issue 3 March 2005
•Biogas Promotion in Kenya Gitonga, Stephen Intermediate Technology Kenya, 1997.
•Anaerobic Digestion - Principles and Practices for Biogas Systems. Gunnerson C. G. and Stuckey D. C., World Bank Technical Paper No 49, The World Bank, 1986.
•An Introduction to biogas, Harris, P. University of Adelaide [Accessed February 2007]
•Biogas in Europe, a general overview Holm-Nielsen, Jens: AI Seadi, Teodorita, The Future of Biomass in Europe 2 ALTENER funded biogas workshop October 2003, Denmark
•Renewable Energy Sources for Fuels and Electricity. Johansen, T.B. et al, Island Press, Washington D.C., 1993.
•Renewable Energy Technologies in Africa. Karekezi, S. and Ranja, T., AFREPEN, 1997.
•Renewable Energy Technologies - their application in developing countries. Kristoferson L. A., and Bokalders V., ITDG Publishing, 1991.
•Biogas China Kangmin, L. & Ho, M-W [Accessed February 2007]
•Renewable energy in developing countries, Lessons for the market Martinot, E. Renewable Energy World 2003 [Accessed February 2007]
•NAWARO Utilizing Biogas on an Industrial Scale NAWARO Bioenergie AE [Accessed February 2007]
•Energy from biomass: a review of combustion and gasification technologies. Quaak, P., Knoef, H. and Stassen, H.E., World Bank technical paper no. 422, Energy Series 1999.
•Biomass, Energy and the Environment: A Developing Country Perspective from India. Ravindranath, N. H. and Hall, D. O., Oxford University Press, 1995.
•A biogas plant for the digestion of fresh undiluted cattle dung Shyam, M. Boiling Point 47. [Accessed February 2007]
•Small-scale biomass gasifiers for heat and power: a global review. Stassen, H.E., World Bank technical paper no. 296, Energy Series 1995.
•From the Fryer to the Fuel Tank: The Complete Guide to Using Vegetable Oil as an Alternative Fuel,