Biogas
Practical Action
are using it to generate electricity; in 2005, biogas units produced 2.9 billion kilowatt-hours of
electricity (NAWARO).
India is planning to deal with one of its major problems – air pollution from transport, through
the use of compressed biogas (CBG). Since over 70% of the world's longterm (2030) growth
in demand for automotive fuels will come from rapidly developing countries like India this is
highly relevant and is currently in the research phase (Biopact).
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 approximate equivalents of various energy sources compared to 1m3 of
biogas.
1992)
Table 1: Biogas fuel equivalents (@ 15˚c & atm pressure)
Energy Source
Equivalent to 1m3 of biogas
Petrol
0.53 - 0.75L
Diesel
0.48 - 0.68L
Firewood
1.50kg
Electricity
1.20kW/h
LPG 0.46kg
Source: Biogas Technology Center (BTC), Chiang Mai University & (FAO,
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
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