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Abstract
Biogas technology, besides supplying
energy and manure, provides an excellent opportunity
for mitigation of greenhouse gas (GHG)
emission and reducing global warming through
substituting firewood for cooking, kerosene for
lighting and cooking and chemical fertilizers. A
study was undertaken to calculate (1) global
warming mitigation potential (GMP) and thereby
earning carbon credit of a family size biogas plant
in India, (2) GMP of the existing and target biogas
plants in the country and (3) atmospheric
pollution reduction by a family size biogas plant.
The GMP of a family size biogas plant was 9.7 t
CO2 equiv. year−1 and with the current price
of US $10 t−1 CO2 equiv., carbon credit of US
$97 year−1 could be earned from such reduction
in greenhouse gas emission under the clean development
mechanism (CDM). A family size biogas
plant substitutes 316 L of kerosene, 5,535 kg
firewood and 4,400 kg cattle dung cake as fuels
which will reduce emissions of NOx, SO2, CO and
volatile organic compounds to the atmosphere by
16.4, 11.3, 987.0 and 69.7 kg year−1, respectively.
Presently 3.83 million biogas plants are operating
in the country, which can mitigate global warming
by 37 Mt CO2 equiv. year−1. Government
of India has a target of installing 12.34 million
biogas plants by 2010. This target has a GMP of
120 Mt CO2 equiv. year−1 and US $1,197 million
as carbon credit under the CDM. However, if all
the collectible cattle dung (225 Mt) produced in
the country is used, 51.2 million family size biogas
plants can be supported which will have a GMP
of 496 Mt of CO2 equiv. year−1 and can earn US
$4,968 million as carbon credit. The reduction in
global warming should encourage policy makers
to promote biogas technology to combat climate
change and integration of carbon revenues will
help the farmers to develop biogas as a profitable
activity.