5.1
Introduction
Depleting fossil fuels is the main concern today. Alternative to fossil fuels is the
availability of biogas. Biogas primarily consists of 50–70% methane and 30–50%
carbon dioxide, with trace amounts of other particulates and contaminants. It can be
produced from various types of waste sources, including landfill materials, animal
manure, wastewater, industrial, institutional and commercial organic wastes, kitchen
waste, and various agricultural wastes.
Biogas is one of the viable alternatives to the burning energy question. In
2014–2015, about 20,700 lakh cubic meters of biogas is produced in India which
is equivalent to 5% of the total LPG consumption in India. The government is also
extending substantial subsidy for setting up of new biogas plants. At a time when the
viability and safety of energy alternatives is being debated, it is pertinent to look at
one of the oldest renewable energy alternatives, Biogas.
Biogas is made up of methane and carbon dioxide. It may have small amounts of
hydrogen sulfide, moisture, and siloxanes. The gases methane, hydrogen, and carbon
monoxide can be combusted or oxidized with oxygen. This energy release allows
biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It
can also be used in a gas engine to convert the energy in the gas into electricity
and heat.
There is unique method of conversion of substrate into biogas under anaerobic
oxidation using methanogenic bacteria under closed system by a process called as
fermentation. Due to enhanced nitrogen content after biogas formation, agrowaste
mixed with dung often results in good biofertilizers. Biogas production shall be a
suitable option for reducing greenhouse gases. Methane gas production can be a
suitable versatile source for vehicle fuel and can be produced in the wet or dry
fermentation system. Most commonly used one is wet fermentation system where
vertical stirred tank is used(Weiland 2010). Biogas is highly combustible due to
presence of CH 4 , H 2 , and CO, so it is proved to be a better biofuel. Additional
features are as follows: it can be used in engines to convert electricity and heat and
thus also can be used as fuel for cars and other vehicles. Biogas can be compressed
well similar to other gases like CNG or natural gas and is very useful in terms of
technoeconomical aspects. Caterpillar Inc. and biogas turbine is used to convert
biogas into electricity and heat.
5.2
Socioeconomic Status and Biogas Production in India
Currently biogas production in India is around 2.07 billion m
3 /year which could be
increased up to 29–48 billion m
3 /year. Currently, biogas has less content of methane
(40–70%) which needs to be enhanced for its use in transportation fuel. Small
country like Nepal is currently producing around 1 million m
3 biogas (Zwolinski
et al. 2013). Out of 215 large biogas plants in the world, India has only 15 biogas
plants till 2013 (Kadam and Panwar 2017), due to low availability of methane (only
45% mostly) which poses problem as compared to natural gas which contains mostly
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S. M. Bhatt and S. Bhat
Introduction
Depleting fossil fuels is the main concern today. Alternative to fossil fuels is the
availability of biogas. Biogas primarily consists of 50–70% methane and 30–50%
carbon dioxide, with trace amounts of other particulates and contaminants. It can be
produced from various types of waste sources, including landfill materials, animal
manure, wastewater, industrial, institutional and commercial organic wastes, kitchen
waste, and various agricultural wastes.
Biogas is one of the viable alternatives to the burning energy question. In
2014–2015, about 20,700 lakh cubic meters of biogas is produced in India which
is equivalent to 5% of the total LPG consumption in India. The government is also
extending substantial subsidy for setting up of new biogas plants. At a time when the
viability and safety of energy alternatives is being debated, it is pertinent to look at
one of the oldest renewable energy alternatives, Biogas.
Biogas is made up of methane and carbon dioxide. It may have small amounts of
hydrogen sulfide, moisture, and siloxanes. The gases methane, hydrogen, and carbon
monoxide can be combusted or oxidized with oxygen. This energy release allows
biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It
can also be used in a gas engine to convert the energy in the gas into electricity
and heat.
There is unique method of conversion of substrate into biogas under anaerobic
oxidation using methanogenic bacteria under closed system by a process called as
fermentation. Due to enhanced nitrogen content after biogas formation, agrowaste
mixed with dung often results in good biofertilizers. Biogas production shall be a
suitable option for reducing greenhouse gases. Methane gas production can be a
suitable versatile source for vehicle fuel and can be produced in the wet or dry
fermentation system. Most commonly used one is wet fermentation system where
vertical stirred tank is used(Weiland 2010). Biogas is highly combustible due to
presence of CH 4 , H 2 , and CO, so it is proved to be a better biofuel. Additional
features are as follows: it can be used in engines to convert electricity and heat and
thus also can be used as fuel for cars and other vehicles. Biogas can be compressed
well similar to other gases like CNG or natural gas and is very useful in terms of
technoeconomical aspects. Caterpillar Inc. and biogas turbine is used to convert
biogas into electricity and heat.
5.2
Socioeconomic Status and Biogas Production in India
Currently biogas production in India is around 2.07 billion m
3 /year which could be
increased up to 29–48 billion m
3 /year. Currently, biogas has less content of methane
(40–70%) which needs to be enhanced for its use in transportation fuel. Small
country like Nepal is currently producing around 1 million m
3 biogas (Zwolinski
et al. 2013). Out of 215 large biogas plants in the world, India has only 15 biogas
plants till 2013 (Kadam and Panwar 2017), due to low availability of methane (only
45% mostly) which poses problem as compared to natural gas which contains mostly
124
S. M. Bhatt and S. Bhat