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Environ Monit Assess (2009) 157:407–418
DOI 10.1007/s10661-008-0545-6
Global warming mitigation potential of biogas
plants in India
H. Pathak ·N. Jain ·A. Bhatia ·
S. Mohanty ·Navindu Gupta
Received: 13 March 2008 / Accepted: 11 September 2008 / Published online: 9 October 2008
© Springer Science + Business Media B.V. 2008
Abstract Biogas technology, besides supplying
energy and manure, provides an excellent oppor-
tunity 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 bio-
gas 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
CO2equiv. year−1and with the current price
of US $10 t−1CO2equiv., carbon credit of US
H. Pathak (B)
Unit of Simulation and Informatics, Indian
Agricultural Research Institute,
New Delhi 110012, India
e-mail: hpathak@cgiar.org
N. Jain ·A. Bhatia ·N. Gupta
Division of Environmental Sciences, Indian
Agricultural Research Institute,
New Delhi 110012, India
H. Pathak ·S. Mohanty
International Rice Research Institute-India,
New Delhi 110012, India
$97 year−1could be earned from such reduction
in greenhouse gas emission under the clean de-
velopment mechanism (CDM). A family size bio-
gas 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,COand
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 warm-
ingby37MtCO
2equiv. 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 CO2equiv. year−1and 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 CO2equiv. year−1and 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.
Keywords Atmospheric pollution ·Biogas plant ·
Carbon trading ·Cattle dung ·Firewood ·
Global warming mitigation potential ·
Greenhouse gas ·India
408 Environ Monit Assess (2009) 157:407–418
Introduction
Biogas technology, using local resources such as
cattle dung and organic wastes, provides an al-
ternate source of energy for cooking and lighting
in rural areas and manure in the form of bio-
gas spent slurry. When organic waste is stored
in the absence of air, a microbial degradation
process starts producing biogas, which is a mix-
ture of 55% to 70% methane (CH4),whichis
the combustible component, 30% to 45% carbon
dioxide (CO2)and a small amount of hydrogen
(H2). Biogas is a smokeless fuel offering an ex-
cellent substitute for kerosene oil, cattle dung
cake, agricultural residues, and firewood, which
are used as fuel in most of the developing coun-
tries. Burning of these fuels leads to atmospheric
pollution due to emission of air pollutants such
as CO, NOx, SO2, volatile organic compounds
and particulates Gadi et al. 2003; Parashar et al.
2005; Venkataraman et al. 2005. It also emits
greenhouse gases (GHG) such as carbon dioxide,
methane and nitrous oxide (N2O), which add to
the global warming and releases soot particles
causing human health problems such as asthma
(Pathak et al. 2006). These problems, however,
can be avoided using the biogas technology, which
can result in a smoke and ash-free kitchen so that
people, particularly women and children in the
developing country should no longer suffer from
pollution. Women in the developing and under-
developed countries are also spared from the bur-
den of gathering firewood. Biogas spent slurry, a
by product of biogas plant, serves as a manure and
can substitute chemical fertilizers for supplying
N, P and K (Pathak et al. 1992). Realization of
these potentials and the fact that India supports
the largest bovine population (286.22 million) of
the world, led to the promotion of biogas plants
in the country in a major way in the late 1970s
(MNES 2006).
There is a scientific consensus that global
warming poses one of the major environmental
challenges and the bulk of the so-called GHGs
originate from fossil fuel consumption (IPCC
2001). There is a need to develop GHG mitigation
strategies to reduce the adverse impacts of climate
change. Biogas technology provides an excellent
opportunity for mitigation of GHG and reducing
global warming through (1) replacing firewood for
cooking, (2) replacing kerosene for lighting and
cooking, (3) replacing chemical fertilizers and (4)
saving trees from deforestation. Recently there
is also business opportunity to a growing global
market in which industrial polluters in developed
countries that cross administered emission limits
of GHGs fund clean technology projects in de-
veloping countries. Greenhouse gas offsets, repre-
senting reductions in gases that contribute to the
warming of the atmosphere, generated in any part
of the world may be used to cancel out excess
GHG emissions anywhere in the world. In the new
math of the “carbon market,” the emission re-
duction will translate into currency called ‘carbon
credits’ (Ball 2007). The notion of carbon credits
is rooted in the Kyoto Protocol, which allows in-
dustrialized countries that agree to carbon caps to
meet their quotas in part by bankrolling emission-
reducing projects at sites where the task will be
less expensive. The Kyoto Agreement advocates
the setting up of a trading system in carbon emis-
sions. With this system every biogas production
unit should sell emission credits under clean de-
velopment mechanism (CDM) which industrial
producers should pay for and every biogas plant
owner should receive a carbon credit from the
trading system. However, there is uncertainty in
the global warming mitigation potential (GMP) of
biogas plants. Studies on quantitative evaluation
of GMP of a biogas plant are limited and there is
a need to develop a mathematical model for cal-
culation of GMP and carbon credit earning from
a biogas plant. The objectives of the study were to
(1) calculate GMP and carbon credit of a family
size biogas plant in India, (2) calculate GMP of the
existing, target and potential biogas plants in the
country and (3) estimate atmospheric pollution
reduction by a family size biogas plant.
Materials and methods
The GMP and carbon credit from the biogas
plants in India was calculated at four levels:
(a) a family size biogas plant (GMP_Family),
(b) the existing biogas plants (GMP_Exist), (c)
target number of biogas plants as set by the
Ministry of Non-Conventional Energy Sources
Environ Monit Assess (2009) 157:407–418 409
(GMP_Target), and (d) potential number of bio-
gas plants when all the collectible cattle dung is
used for biogas production (GMP_Potential).
The GMP and carbon credit from a family
size biogas plant (GMP_Family) was calculated
considering five factors as shown in the following
equation.
GMP (CO2equiv.)
=GWP of CO2emission reduction from
kerosene and firewood savings
+GWP of CH4emission reduction from
firewood saving
+GWP of CO2emission reduction from N, P
and K fertilizer production
+GWP of N2O emission reduction from N
fertilizer application – GWP of CH4leakage
from biogas digester.
A simplified scheme of various calculations,
the inputs used, driving variables and resultant
outputs is shown in Fig. 1and various coefficients
used are listed in Table 1.Tostartwith,biogas
generation by a family size biogas plant (3 m3
capacity), operated with dung produced by four
cattle, commonly reared in a household, was cal-
culated using the relationship of 0.5 m3biogas
kg−1dry dung (Khendelwal and Mahdi 1986).
It was assumed that 80% of generated biogas
would be used for replacing firewood and 20%
for replacing kerosene as fuel. Kerosene and fire-
wood equivalents of the produced biogas were
then calculated using the calorific values of these
fuels (Table 1). This implied that a family size
biogas plant would save the calculated quantities
of kerosene and firewood, which would otherwise
emit GHG to the atmosphere upon burning as
fuel. Carbon dioxide emissions from burning of
Fig. 1 Schematic
overview of the inputs,
driving variables and
outputs for calculating
global warming
mitigation potentials
of a family size
(GMP_Family), the
existing (GMP_Exist),
target number
(GMP_Target), and
potential number
(GMP_Potential)of
biogas plants in India.
The values given in the
parentheses are for a
family size biogas plant
per year. GWP global
warming potential, GMP
global warming
mitigation potential
3 m3
capacity
plant
Kerosene (316 l)
(20% of biogas)
Firewood (5535 kg)
(80% of biogas)
Biogas (2200 m3)Slurry (1725 kg C)
N, P, and K fertilizer
(62, 22, and 35 kg)
GWP (762 kg CO2) GWP (10571 kg CO2)GWP (302 kg CO2)
Dung
(4400 kg)
Leakage of CH4
(94 kg, GWP
1968 kg CO2)
GMP_Family (9667 kg CO2), Carbon credit (97 US $)
No. of existing
biogas plants
GMP_Exist
Carbon credit
No. of target
biogas plants
GMP_Target
Carbon credit
Cattle dung
production
GMP_Potential
Carbon credit
410 Environ Monit Assess (2009) 157:407–418
Table 1 Coefficients used
for calculation of GHG
mitigating potential of
biogas plant
Parameter Conversion factor
CO2emission from kerosene burning (kg l−1)2.41
CO2emission from firewood burning (kg kg−1)1.83
CH4emission from firewood burning (g kg−1)3.9
Calorific value of biogas (kcal l−1)4.81
Calorific value of CH4(kcal l−1)8.0
Density of methane (kg m−3)0.71
Calorific value of kerosene (kcal l−1)8,365
Calorific value of firewood (kcal kg−1)3,824
Kerosene equivalent of biogas (l m−3)0.58
Density of kerosene (kg l−1)0.81
Firewood equivalent of biogas (kg m−3)1.26
Annual dung production per cattle (kg dry wt.) 1,100
Biogas production from cattle dung (m3kg−1dry wt.) 0.5
Methane content in biogas (%) 60
C content in slurry (kg kg−1dry wt.) 0.4
N content in slurry (kg kg−1dry wt.) 0.014
P content in slurry (kg kg−1dry wt.) 0.011
K content in slurry (kg kg−1dry wt.) 0.008
CO2emission for N fertilizer production (kg kg−1)1.3
CO2emission for P fertilizer production (kg kg−1)0.2
CO2emission for K fertilizer production (kg kg−1)0.2
N2O-N emission from N fertilizer application (kg kg−1)0.07
Methane leakage from biogas plants (% of production) 10
GWP of CO2(kg CO2equiv. kg−1)1
GWP of CH4(kg CO2equiv. kg−1)21
GWP of N2O(kgCO
2equiv. kg−1)310
Carbon credit (US $ t−1CO2equiv.) 10
kerosene and firewood were taken as 2.41 kg l−1
and 1.83 kg kg−1, respectively. Firewood burning
also emits CH4at 3.0 g C kg−1. Burning efficiency
of kerosene and firewood were taken as 80% and
40%, respectively as in rural India conventional
cooking stoves are generally inefficient (Chawla
1986).
The most popular biogas plants installed in
the country are of two types (1) floating drum
type and (2) fixed dome type. Both the types
have exposed areas around the floating gas holder,
feed inlet and outlet pipes, the slurry displace-
ment chambers and the slurry drying pits from
where the biogas is leaked to the atmosphere
(Khoiyangbam et al. 2004). Leakage of CH4from
the digester was taken as 10%, a conservative
estimation based on IPCC range of 5–15% (IPCC
2001).
Biogas slurry, a by-product of biogas plant, is
applied as manure to substitute chemical fertilizer.
As there is negligible mass loss of substrate (cattle
dung) as biogas, it was assumed that 1 t of cattle
dung would generate similar amount of biogas
spent slurry containing 1.4% N, 0.5% P and 0.8%
K on dry weight basis (Subrian et al. 2000; Tandon
and Roy 2004). Substitution of chemical fertilizer
with spent slurry reduces CO2emission, which
would emit for production of fertilizer. Emis-
sion of CO2was calculated using the following
equation (Schlesinger 1999;Lal2004;Pathakand
Wassmann 2007).
Emission of CO2=N fertilizer ×1.3
+(P fertilizer +K fertilizer)
×0.2
Saving of N fertilizer due to replacement by biogas
slurry would also reduce emission of nitrous oxide
at a rate of 0.7% of the applied N (Bhatia et al.
2004; Malla et al. 2005).
Global warming potential (GWP) is an index
defined as the cumulative radiative forcing be-
tween the present and a chosen later time ‘hori-
zon’ caused by a unit mass of gas emitted now.
Environ Monit Assess (2009) 157:407–418 411
It is used to compare the effectiveness of each
GHG to trap heat in the atmosphere relative to
a standard gas, by convention CO2.TheGWP
for CH4(based on a 100-year time horizon) is 21
while that for N2O is 310 when the GWP value
for CO2is taken as 1. The GWP of the calculated
GHG emission reduction was calculated using the
following equation.
GWP =CH4×21 +N2O×310 +CO2×1
Prices of carbon credit have ranged from US $5
to 20 Mg−1CO2-equiv., depending on volume and
timing (Hawn 2006). Such credits are being sold
elsewhere in the world as a result of the Kyoto
Protocol, typically between US $5 and 8 Mg−1
CO2-equiv. (Ball 2007). However, some estimates
suggest that the price would run upwards in fu-
ture. In the current estimate a price of US $10
Mg−1CO2-equiv. has been considered.
To calculate the GMP of existing biogas plants
in India (GMP_Exist) data on number of fam-
ily size biogas plants in different states of the
country were obtained from the Ministry of Non-
Conventional Energy Sources, Government of In-
dia (MNES 2006). The values of the GMP and
carbon credit of a family size biogas plant were
then extrapolated to the reported number of ex-
isting biogas plants in the country to estimate
GMP_Exist (Fig. 1). The GMP for target number
of biogas plants (GMP_Target) was calculated by
extrapolating the GMP of a family size biogas
Table 2 Population of
livestock, total dung
production and dung
available for biogas
production in different
states of India in
2000–2001
aSource: MAC (1998,
2006)
bDung productions (dry
wt.) per cattle and buffalo
are 1,100 and 1,350 kg
year−1, respectively
(Gaur 1995)
cDung lost during
collection (30%) and used
for construction (1–9%)
was deducted from total
production (TERI 2001)
dBihar, Madhya Pradesh
and Uttar Pradesh
include Jharkhand,
Chhattishgarh and
Uttarakhand, respectively
States aCattle aBuffalo bTotal dung cDung for biogas
population population produced production
Million Million Mt year−1Mt year−1
A and N Island 0.05 0.01 0.07 0.05
Andhra Pradesh 10.95 9.13 24.37 14.87
Arunachal Pradesh 0.32 0.01 0.36 0.25
Assam 10.12 0.97 12.44 8.58
Bihard16.32 6.25 26.38 18.20
Chandigarh 0.01 0.02 0.04 0.03
D and N Haveli 0.05 0.00 0.06 0.04
Delhi 0.04 0.25 0.38 0.26
Goa, Daman and Diu 0.01 0.00 0.01 0.01
Gujarat 6.84 5.27 14.64 9.81
Haryana 2.13 4.37 8.25 5.69
Himachal Pradesh 2.25 0.79 3.54 2.44
Jammu and Kashmir 3.05 0.73 4.34 2.99
Karnataka 13.18 4.26 20.24 13.56
Kerala 3.13 0.33 3.89 2.61
Madhya Pradeshd28.60 7.97 42.22 29.13
Maharashtra 17.44 5.44 26.53 17.78
Manipur 0.72 0.11 0.94 0.65
Meghalaya 0.54 0.03 0.63 0.44
Mizoram 0.06 0.01 0.07 0.05
Nagaland 0.33 0.03 0.41 0.28
Orissa 13.58 1.51 16.98 11.71
Pondicherry 0.09 0.01 0.11 0.07
Punjab 3.67 4.26 9.78 6.75
Rajasthan 17.44 5.44 26.53 17.78
Sikkim 0.20 0.00 0.22 0.15
Tamil Nadu 9.28 2.82 14.01 9.25
Tripura 0.95 0.02 1.07 0.74
Uttar Pradeshd26.33 20.11 56.10 37.03
West Bengal 17.44 0.97 20.49 14.14
Total 205.10 81.12 335.12 225.34
412 Environ Monit Assess (2009) 157:407–418
plant to the target number of biogas plants as
set by the Ministry of Non-Conventional Energy
Sources, Govt. of India (Fig. 1).
The (GMP_Potential) i.e., GMP when all the
collectible cattle dung in the country is used for
biogas production was calculated based on total
cattle population in various states in India, total
dung production, dung lost during collection and
number of biogas plants that can be supported by
this dung (Fig. 1). Total production of dung (DT)
in the country was calculated as follows.
Total dung (DT)=T(NT×DEX)
Where, Tis the number of the livestock category
(cattle, buffalo), NTis the number of animals in
each category, DEX is the annual average dung
excretion per head for each livestock category.
However, some amount of dung is lost during
collection and used for construction. Thus actual
availability of dung for biogas production (DBG)
was calculated as follows.
Dung available for biogas production (DBG)
=DT×[1−(DCL +DCN)]
Where DCL and DCN are the fractions of dung
that are used for construction and lost during
collection, respectively. Data on cattle population
in different states of India (Table 2) was obtained
Ministry of Agriculture and Cooperation, Govt. of
India (MAC 2006). Data on dung produced per
cattle and buffalo were reported by Gaur (1995).
Dry matter content in the fresh dung was taken as
18% (Chawla 1986;Bhatiaetal.2004). Data on
dung that is used for construction were obtained
from Gaur (1995), whereas loss of dung during
collection was taken from TERI (2001).
Data on atmospheric pollution load due to
burning of kerosene, firewood and cattle dung
cake were obtained from literature (Shekar
Reddy and Venkataraman 2000,2002; Gadi et al.
2003; Hobson and Thistlethwaite 2003; Parashar
et al. 2005; Venkataraman et al. 2005)andare
summarized in Table 3. Reduction of pollution
due to a family size biogas plant was calculated
based on the saving of kerosene, firewood and
cattle dung cake. It was assumed that total amount
of cattle dung used in a biogas plant would be
saved from burning whereas 80% of generated
biogas would save firewood and 20% would save
kerosene as fuel.
Table 3 Emission of atmospheric pollutants from kerosene, firewood and cattle dung cake and amount of pollution
reduction due to use of biogas from a family size plant
Pollutant Atmospheric emission factor Pollution reduction due to a Total
(g kg−1fuel) biogas plant (kg year−1)
Kerosene Firewood Dung cake Kerosene Firewood Dung cake
Oxides of N (NOx) 2.3a2.2b0.8b0.7 12.2 3.5 16.4
Oxides of S (SO2)4.0a0.7b1.4b1.3 3.9 6.2 11.3
Carbon monoxide (CO) 1.8a99.3e99.3h0.6 549.6 436.9 987.1
Volatile organic compounds 0.5a7.0a7.0h0.2 38.7 30.8 69.7
Particulate matter 10 0.3a3.0a3.0h0.1 16.6 13.2 29.9
Particulate matter <2.5 0.3c2.1c6.5c0.1 11.6 28.6 40.3
Organic matter 1.3c1.3c4.0c0.4 7.2 17.6 25.2
Black carbon 0.3c0.6g2.5g0.1 3.3 11.0 14.4
Organic carbon 0.2d3.5f12.6f0.1 19.4 55.4 74.9
aSource: Hobson and Thistlethwaite (2003)
bSource: Gadi et al. (2003)
cSource: Shekar Reddy and Venkataraman (2000)
dSource: Shekar Reddy and Venkataraman (2002)
eSource: IPCC (1996)
fSource: Parashar et al. (2005)
gSource: Venkataraman et al. (2005)
hData not available and values similar to firewood have been taken for approximation
Environ Monit Assess (2009) 157:407–418 413
Results and discussion
Annual GMP of a family size biogas plant
A family size biogas plant with 4 cattle producing
4,400 kg dung (dry weight) produces 2,200 m3of
biogas per annum (Table 4). This amount of bio-
gas substitutes 316 L of kerosene and 5,535 kg of
firewood, the GWP of which are 762 and 10,571 kg
CO2equiv., respectively. Biogas slurry generated
by the biogas plant is 1,725 kg C which substitutes
62, 22 and 35 kg N, P and K fertilizer, respectively.
The GWP for producing equivalent amounts of
chemical N, P and K fertilizer is 302 kg CO2equiv.
Moreover, application of 62 kg N fertilizer in soil
emits 0.43 kg N2O-N with the GWP of 210 kg
CO2equiv. (Bhatia et al. 2004; Malla et al. 2005).
However, the biogas plant leaks methane of 94 kg
CO2equiv. from its exposed areas and contributes
to the global warming. The net GMP of the biogas
plant is 9,667 kg CO2equiv. with a carbon credit
of US $97 year−1at the current price of US $10 t−1
CO2equiv. (Table 4).
Table 4 Annual greenhouse gas mitigation potential
(GMP) and carbon credit from a family size biogas plant
in India
Parameter Value
No. of cattle 4
Total dung (kg dry wt.) 4,400
Biogas production (m3)2,200
aKerosene equiv. 20% of biogas (l) 316
GWP for kerosene (kg CO2equiv.) 762
aWood equiv. of 80% of biogas (kg) 5,535
GWP for wood (kg CO2equiv.) 10,571
Slurry produced (kg C) 1,725
Fertilizer N equiv. (kg) 62
Fertilizer P equiv. (kg) 22
Fertilizer K equiv. (kg) 35
GWP for fertilizer (kg CO2equiv.) 302
CH4leakage per plant (kg) 94
GWP of leaked CH4(kg CO2equiv.) 1,968
bGMP (kg CO2equiv.) 9,667
Price of carbon credit (US $ t−1CO2equiv.) 10
Carbon credit per plant (US $) 97
aIt is assumed that 20% and 80% of biogas is used to
replace kerosene and firewood, respectively. Efficiency of
kerosene and firewood are 80% and 40%
bGMP (kg CO2equiv.) =762 +10,571 +302 −1,968 =
9,667
Annual GMP of the existing biogas plants
In 1970s India initiated a major programme for
the promotion of biogas plants as an answer to
the growing fuel crisis (MNES 2006). This pro-
gramme has been a major success and presently
3.83 million biogas plants are operating in the
country. The state of Maharashtra has the high-
est number of biogas plants followed by Uttar
Pradesh, Andhra Pradesh, Karnataka and Gujarat
(Table 5). Estimated GMP for these existing bio-
gas plants in the country is 37 Mt CO2equiv.
year−1with carbon credit of US $372 million
year−1(Table 5). Maharashtra has the maximum
GMP (6.97 Mt CO2equiv.) followed by Uttar
Pradesh, Andhra Pradesh, Karnataka and Gu-
jarat. Chandigarh and Andaman and Nicobar
Islands have the minimum GMP.
Annual GMP of target biogas plants
Government of India has a target of installing
12.34 million biogas plants by 2010 out of which
only 31% biogas plants are installed (Table 5).
Target of installing biogas plants is highest for
Uttar Pradesh followed by Madhya Pradesh,
Andhra Pradesh, Rajasthan, Maharashtra and
Bihar. Estimated GMP for the target biogas plants
(GMP_Target) is 120 Mt CO2equiv. year−1.If
the target is achieved, India can earn about US
$1,196.9 million year−1as carbon credit (Table 5).
The states of Uttar Pradesh, Madhya Pradesh,
and Andhra Pradesh are the highest beneficiary
earning US $188.0, 144.6 and 103.3 million year−1,
respectively, by selling the emission reductions
from the biogas plants.
Annual GMP with all collectible cattle
dung used for biogas
India supports the largest bovine (cattle + buf-
falo) population (286.22 million) of the world
(Table 2). Whereas cattle population in Madhya
Pradesh is maximum followed by Uttar Pradesh,
Maharashtra, Rajasthan and West Bengal, buf-
falo and bovine population is highest in Uttar
Pradesh. Total dung production is maximum in
Uttar Pradesh, followed by Madhya Pradesh and
Bihar. In the country 335 Mt dung is produced
414 Environ Monit Assess (2009) 157:407–418
Table 5 Annual greenhouse gas mitigation potential and carbon credits from the existing and potential biogas plants in various states of India
State aExisting biogas plants aTarget biogas plants bPotential biogas plants
No. of GMP (000 C credit No. of GMP (000 C credit No. of GMP (000 C credit
biogas t CO2(million US $ biogas t CO2(million US $ biogas t CO2(million US $
plants (‘000) equiv.) year−1) plants (‘000) equiv.) year−1) plants (‘000) equiv.) year−1)
A and N Islands 0.1 1 0.0 2.2 21 0.2 11 108 1.1
Andhra Pradesh 400.9 3,888 38.9 1,065.0 10,331 103.3 3,379 32,773 327.7
Arunachal Pradesh 2.2 21 0.2 7.5 73 0.7 57 552 5.5
Assam 58.7 569 5.7 307.0 2,978 29.8 1,950 18,919 189.2
Bihar 124.9 1,212 12.1 733.0 7,110 71.1 4,137 40,128 401.3
Chandigarh 0.1 1 0.0 1.4 14 0.1 6 56 0.6
Chhattisgarh 17.0 164 1.6 400.0 3,880 38.8 0.0
D and N Haveli 0.2 2 0.0 2.0 19 0.2 9 86 0.9
Delhi 0.7 7 0.1 12.9 125 1.3 60 584 5.8
Goa 3.7 36 0.4 8.0 78 0.8 1 13 0.1
Gujarat 378.8 3,675 36.7 554.0 5,374 53.7 2,230 21,630 216.3
Haryana 49.2 477 4.8 300.0 2,910 29.1 1,294 12,551 125.5
Himachal Pradesh 44.9 435 4.4 125.0 1,213 12.1 555 5,385 53.8
Jammu a Kashmir 2.1 21 0.2 128.0 1,242 12.4 680 6,600 66.0
Jharkhand 2.1 20 0.2 100.0 970 9.7 0.0
Karnataka 392.4 3,806 38.1 680.0 6,596 66.0 3,082 29,895 298.9
Kerala 108.3 1,051 10.5 150.0 1,455 14.6 592 5,746 57.5
Environ Monit Assess (2009) 157:407–418 415
Madhya Pradesh 247.5 2,401 24.0 1,491.0 14,463 144.6 6,621 64,220 642.2
Maharashtra 719.1 6,975 69.8 897.0 8,701 87.0 4,040 39,189 391.9
Manipur 2.1 21 0.2 38.0 369 3.7 148 1,437 14.4
Meghalaya 4.2 41 0.4 24.0 233 2.3 99 963 9.6
Mizoram 3.5 34 0.3 5.0 49 0.5 12 113 1.1
Nagaland 2.6 25 0.3 6.7 65 0.6 64 621 6.2
Orissa 224.4 2,176 21.8 605.0 5,869 58.7 2,662 25,825 258.3
Pondicherry 0.6 6 0.1 4.0 39 0.4 16 154 1.5
Punjab 80.7 783 7.8 411.0 3,987 39.9 1,534 14,881 148.8
Rajasthan 66.9 649 6.5 915.0 8,876 88.8 4,040 39,189 391.9
Sikkim 5.6 54 0.5 7.3 71 0.7 35 335 3.4
Tamil Nadu 210.0 2,037 20.4 615.0 5,966 59.7 2,102 20,385 203.8
Tripura 2.4 24 0.2 28.0 272 2.7 168 1,629 16.3
Uttar Pradesh 408.0 3,957 39.6 1,938.0 18,799 188.0 8,416 81,631 816.3
Uttarakhand 6.6 64 0.6 83.0 805 8.1 0.0
West Bengal 263.6 2,557 25.6 695.0 6,742 67.4 3,214 31,175 311.7
Total 3,834.1 37,191 371.9 12,339.0 119,688 1,196.9 51,214 496,774 4,967.7
Bihar, Madhya Pradesh and Uttar Pradesh include Jharkhand, Chhattishgarh and Uttarakhand, respectively
GMP greenhouse gas mitigation potential
aData obtained from Ministry of Non-Conventional Energy Sources, Govt. of India (2006)
bCalculated from the total cattle dung production in different states
416 Environ Monit Assess (2009) 157:407–418
per annum out of which 110 Mt is lost during
collection or used for construction purposes. The
remaining 225 Mt dung is available for biogas
production, which can support 51.2 millions of
family size biogas plants. These large number
of biogas plants have potential to reduce GMP
(GMP_Potential) by 496 Mt of CO2equiv. year−1.
Under this scenario India can earn US $4,818.7
million year−1as carbon credits. Uttar Pradesh,
Madhya Pradesh and Bihar will be the major
beneficiaries earning US $791.8, 622.9 and 389.2
million year−1, respectively.
There are some other sources of organic C,
which can be used for production of biogas. For
example, total municipal solid waste (MSW) gen-
eration from major Indian cities (35 metro cities
and 24 state capitals) is about 40 thousand t day−1
(CPCB 2006). Delhi, the national capital, gen-
erates the largest MSW (5.9 thousand t day−1)
followed by Greater Mumbai (5.3 thousand
tday
−1), Chennai (3.0 thousand t day−1), Kolkata
(2.6 thousand t day−1), Hyderabad (2.2 thousand
tday
−1), and Bangalore (1.7 thousand t day−1).
The biodegradable organic matter in MSW is
about 28% by mass. So MSW from Indian cities
generates 11.2 thousand t C day−1or 4.1 Mt C
year−1. The MSW thus is an important source of
organic C and a potential source of biogas. But
MSW alone can not be utilized for economic bio-
gas production as this needs some starter i.e., a
readily digestible C source for anaerobic fermen-
tation and production of biogas. When mixed with
cattle dung as a starter in the ratio of 1:1 by mass, it
produces 270 L biogas kg−1of waste on dry matter
basis. However, making cattle dung available in
cities is a constraint and the technology of pro-
ducing biogas from MSW has not been popular in
the country. Therefore, we did not include biogas
production potential from MSW in this study.
Atmospheric pollution reduction
by a family size biogas plant
Burning of kerosene, firewood and cattle dung
cake as fuels emits 0.8 to 2.2, 0.7 to 4.0 g kg−1NOx,
and SO2, respectively alongwith varying amounts
of CO, volatile organic compounds, particulate
matters, organic matter, black carbon and organic
carbon (Table 3). A family size biogas plant sub-
stitutes 316 L of kerosene, 5,535 kg firewood and
4,400 kg cattle dung cake per annum as fuels
(Table 3). Substitution of kerosene reduces emis-
sions of NOx, SO2and CO by 0.7, 1.3, and 0.6 kg
year−1. Substitutions of firewood and cattle dung
cake results in the reduction of 3.5 to 12.2, 3.9
to 6.2, 436.9 to 549.6 and 30.8 to 38.7 kg year−1
NOx, SO2, CO and volatile organic compounds,
respectively. Total reductions of NOx, SO2,CO
and volatile organic compounds by a family size
biogas plant are 16.4, 11.3, 987.0 and 69.7 kg
year−1.
Implication of life-span and season
on GMP of a biogas plant
The most common biogas plant in the country
is the Khadi and Village Industries Commission
(KVIC)-design plant. It is made of the following
parts: (1) Digester: This is the fermentation tank
and is built partially or fully underground. It is
generally cylindrical in shape and made up of
bricks and cement mortars. It holds the slurry
within it for the period of digestion for which
it is designed. (2) Gas holder: This component
is meant for holding the gas after it leaves the
digester. It may be a floating drum or a fixed
dome on the basis of which the plants are broadly
classified. The gas connection is taken from the
top of this holder to the gas burners or for any
other purposes by suitable pipelines. The floating
gas holder is made up of mild steel sheets and
angle iron. The fixed dome is made up of concrete.
(3) Slurry mixing tank: This is a tank in which the
dung is mixed with water and fed to the digester
through an inlet pipe. The tank is made up of brick
and cement mortar. (4) Outlet tank and slurry
pit: An outlet tank is usually provided in a fixed
dome type of plant from where slurry in directly
taken to the field or to a slurry pit. In case of a
floating drum plant, the slurry is taken to a pit
where it can be dried or taken to the field for direct
applications.
Average life of digester, fixed dome, slurry
mixing tank and outlet tank, which are made up
of brick, cement and concrete is about 25 years.
Therefore, life of a fixed dome plant is about
25 years. The life of the gas holder, which is made
up of mild steel is about 10 years. With minor
Environ Monit Assess (2009) 157:407–418 417
repair the holder lasts for another 2–3 years. The
gas holder, however, can be easily replaced with
another. Thus, by replacing the gas holder for
once, the plant will run for 25 years. However,
there is no significant implication of life span of
the plant on GHG emission reduction potential as
the calculation has been based on annual basis.
Different seasons of the year affect bio-
gas production mainly because of difference in
temperature. About 10–15% reduction in bio-
gas production is recorded in winter season
(November– February) and 7% reduction in rainy
season (July–August) because of low temperature
compared to summer seasons. However, the data
presented in this study take these reductions into
account as the calculations of GMP are based on
amount of cattle dung used for biogas production.
Implementation of the GMP scheme
In order to expedite formulation and implemen-
tation of biogas plant schemes in the country, the
government of India has strengthened the state
and district nodal agencies with adequate staff
and instrumental facilities. Besides this, agencies
such as Khadi and Village Industries Commission
(KVIC) and national banks are also helping in
formulating the schemes and installation and op-
eration of biogas plants. The procedure for instal-
lation and maintenance of biogas plants has been
systematized under the National Bio-gas and Ma-
nure Management Programme (NBMMP). These
agencies should be technically upgraded for peri-
odic collection of data on GMP of biogas plants.
A sampling plan can be developed for some rep-
resentative biogas plants at different districts for
regular monitoring of GHG emission and GMP.
To address the field problems, which are mainly
socio-economic and organizational in nature, the
rural communities, village panchayats, and non-
governmental organizations also should be in-
volved in this operation.
Conclusions
Biogas plant is a useful technology for the
resource-poor farmers in developing countries. So
far it has been viewed as an alternate energy
source but it can play a major role in mitigating
global warming by substituting cooking fuel and
chemical fertilizer. Despite the concerted efforts
by state governments its adoption has not been
very high because of high up-front investment
cost of constructing a biogas plant (US $900–
1,000 for a family size biogas plant). The reduction
in global warming should encourage the policy
makers to promote biogas technology to combat
climate change and integration of carbon rev-
enues will help the farmers to develop biogas as
a profitable activity. With the large number of
existing and potential biogas plants, India has a
good opportunity to solve its energy crisis, re-
duce global warming and earn substantial revenue
under the new regime of carbon marketing. The
mechanism of carbon market should be used to
promote installation of biogas plants by making
these financially viable.
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