Conference-Proceedings_ICCESD-2014_for_KNK

Proceedings of the 2nd
International Conference on Civil Engineering for Sustainable Development
(ICCESD-2014), 14~16 February 2014, KUET, Khulna, Bangladesh, ISBN: 978-984-33-6373-2 (CD-Rom)
GREENHOUSE GAS EMISSION SCENARIO OF EXISTING ELECTRICITY
GENERATION TECHNOLOGIES IN DHAKA CITY
Karishma Niloy Kibria
Lecturer, Department of Disaster and Environmental Engineering, Chittagong University of Engineering &
Technology (CUET), Chittagong, Bangladesh.
e-mail: karishmakibria037@gmail.com
ABSTRACT
The future economic development trajectory for Dhaka city is likely to result in a rapid and accelerated growing
energy demand, with attendant shortages and problems. .Due to the predominance of fossil resources in the
energy mix, there are negative environmental externalities caused by electricity generation. At the same time,
the country has very limited fossil fuel reserves to generate electricity. In this context, it is imperative to develop
and promote alternative energy resources that can lead to sustainable and environmentally friendly energy
systems. There are opportunities for renewable energy technologies for power generation under the climate
change regime.They contribute to the mitigation of global climate change through the reduction of GHG
emissions, and they confirm to national priorities by leading to the development of local capacities and
infrastructure. Energy Ministry of Bangladesh government has introduced a solar energy policy for the housing
industry. This policy requires that all newly constructed buildings must include a rooftop solar power unit with
an output no less than 3% of the building’s total peak load. Mitigation of Greenhouse gas emission through
installation of solar panels at Dhaka city residential zone is evaluated using Greenhouse Gas emission
guidelines: Stationary combustion sources by North Carolina division of Air quality.Solar installed systems
have excellent emission recovery potential which can play a significant role in improvement of climate.The
renewable energy resources may serve to supplement the long-term energy needs of Bangladesh to a significant
level.
Keywords:Emission, Greenhouse gas, mitigation, renewable energy, solar panel
1. INTRODUCTION
Climate change is one of the most critical global environmental, social, and economic challenges of the century
that the entire world is facing.The major challenge for twenty-first century society is and will continue to be the
implementation of a global energy production infrastructure that can satisfy total demand, minimize cost,
produce as little pollution as possible and extend the lifetime of fossil fuels. New technologies are being
developed to reduce the disadvantageous effects of energy production and provide better means to capture and
store energy passively. If we were to run out of fossil fuels it could lead to extreme economic strain while an
alternative was developed to replace our dependence on these fuels. It could also cause our structured society to
collapse in a fight for the remaining fuel. A shortage would cause almost all of our current technologies to
become useless.Solar energy has experienced an impressive technological shift. The rapid expansion of the solar
energy market can be attributed to a number of supportive policy instruments, the increased volatility of fossil
fuel prices and the environmental externalities of fossil fuels, particularly greenhouse gas (GHG) emissions.
Globally, energy sector is identifies as one of the main sector of green house gas (GHG) emissions. Developed
industrial nations are responsible for reducing GHG emissions as per Kyoto Protocol. However, the developing
nations are not bounded to reduce the GHG emission but there economic development will be influenced by the
GHG mitigation strategies of the developed nations. Moreover,the developing nations are expected to get
financial and technological support demy Kyoto and post Kyoto phases. Recently, many developing countries
have given attention to the study of GHG emissions and finding the alternative paths for GHG mitigation. Like
many developing nations, it is important for Bangladesh to estimate the GHG emission level, future trends of
GHG emissions and to identify mitigation options. It is important to study and to estimate the GHG emissions of
energy sector. It is also needed to identify and to explain the different mitigation options for developing mid
term and long-term energy sector of the country. This study presents an estimation of greenhouse gas emission
from existing electricity generation technologies and also mitigation of greenhouse gases through solar panel
installation at residential area of Dhaka city.

2nd
International Conference on Civil Engineering for Sustainable Development (ICCESD-2014)
The overall objectives of the paper are:
Estimating Greenhouse gas emission from conventional electricity generation system provided at the
residential area of Dhaka city on fiscal year 2010-2011.
Estimating mitigation of greenhouse gas after installing solar panel in a residential area of Dhaka city in
fiscal year 2010-11.
Analyzing mitigation of Greenhouse gas emission from conventional power system by installing standard
solar panel at Dhaka city from Fiscal year 2008-2009 throughout the life span of solar panel.
2. METHODOLOGY
2.1 CO2 Emission
The amount of Carbon di oxide emission from electricty genertion sector in the fiscal year 2010-11 at the
residential area of the Dhaka city is calculated using calculation based method.Calculation based method is a
mass balance approach where the carbon content and carbon oxidation factors are applied to the fuel input levels
to determine emissions.
Table 1: Emission factors for calculating CO2 emissions - fuel analysis approach[1]
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Calculation based method is also consists of two approach –
1. Fuel Analysis approach.
2. Generalized approach
In this paper Calculation method-Fuel analysis approach is followed to estimate greenhouse gas emission from
the conventional power generation system at the residential area of Dhaka city. The emission is calculated
using following equation.
Yearly carbon di oxide emission potential:
[1]
Where,
= Total CO2 emitted from all fuel types (ton/year)
i = fuel type – bituminous coal , fuel oil , natural gas , etc
Fueli = amount of fuel i combusted (ton/year , scf/year or barrels /year )
Heat Contenti = heat content of fuel type i(MMBtu/ton, MMBtu/scf,MMBtu/barrel)
Carbon Contenti = carbon content coefficient of fuel type i (Kg C/MMBtu)
Oxidation Factori = farction of fuel type i oxidized (table 1)
= molecular weight of carbon di oxide (44)
= molecular weight of carbon (12)
C = conversion factor from kg to ton (1 / 907.2)
An emission factor which was used in the emission equation is collected from table 1.
The measurement of total CO2 emission from the fuel combustion in electricity generation plant in a particular
area for a particular fiscal year is done by adding all estimated CO2 emission from three sources (natural gas, oil
and bituminous coal). The whole procedure of estimating emissions is divided in following steps.
2.1.1 Determination of the amount of fuel combusted:
The amount of fuel combusted in electricty generation for dhaka city residential area is derived from the power
consumption data of that area in a particular fiscal year 2010-2011 through an indirect method.Electricity
generation data is collected from DPDC (Dhaka Power and Distribution Company) which covers south Dhaka
city corporation zone and DESCO (Dhaka Electricity Supply Corporation) which covers north Dhaka.
Usually three types of natural resources are used to produce electricity in conventional power system of
Bangladesh.
Electricity production from natural gas sources ( % of total) = 89
Electricity production from coal sources ( % of total)= 1.8
Electricity production from oil sources ( % of total)=5
2.1.2 Conversion of the amount of fuel combusted into energy units:
To convert fuel combusted on a mass/volume basis to energy units, the heating value of each fuel type is used.
The fuel supplier often provides the heating value of purchased fuel because it is directly related to the useful
output of the fuel. Heating value can also be determined through direct fuel sampling and analysis. If heating
value data are available, either from the fuel supplier or direct sampling, then that data should be used to
represent Heat Content in Equation. Since such data are not available, so default fuel specific heating values
listed in Table 3.1 was used.
2.1.3 Determination of carbon content of fuel consumed :
Carbon content of fuel, expressed in terms of mass of carbon per mass, volume or energy of fuel, can also be
determined by fuel sampling and analysis. If carbon content data are available, either from the fuel supplier or
direct sampling, then that data should be used to represent Carbon Content in Equation. As such data are not
available, so U.S. average carbon content coefficients listed in Table 3.1 are used.
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2.1.4 Calculation of Carbon emitted:
When fuel is burned, most of the carbon is eventually oxidized to CO2. To account for the small fraction of
carbon that may not be oxidized during combustion, the carbon content of fuel is multiplied by the Oxidation
factor. As I do not have oxidation factors specific to electricity combustion Sources, default oxidation factor of
1.00 or 100% oxidation was used.
2.1.5 Conversion of CO2 emitted to tons:
To obtain total annual CO2 emitted in units of tons/year, carbon emissions were multiplied by the ratio of
molecular weight of CO2 to carbon (44/12) and the conversion factor from kg to short tons (1/907.19)
2.2 CH and N2O Emissions Reporting
Unlike CO2, CH and N2O emissions depend not only on fuel characteristics, but also on other factors
Such as:
Technology type, size, age, and efficiency,
Combustion characteristics
Use of air pollution control equipment, and
Routine operational and maintenance practices.
The emissions of methane and nitrous oxide are calculated using following equation, NCDAQ (2009).
Yearly Methane (CH4) and Nitrous oxide (N2O) emission potential:
Where,
= Total CH and N2O emitted from all fuel type, including bio fuels (ton/year)
i = fuel type - bituminous coal, fuel oil, natural gas, etc.
Fueli = amount of fuel type i combusted on energy basis (MMBtu/year)
Emission Factori = CH or N2O emission factors based on fuel type, technology (g/MMBtu) (table 2)
C1 = conversion factor from g to ton (1/907,200)
An emission factor which was used in the emission equation is collected from table 2.
Table 2: Emission factor for calculating CH4 & N2O Emission – Generalized Approach [1]
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CH4 and N2O account for significantly less emissions from stationary combustion than CO2.The estimation is
conducted for three different sources (natural gas, oil and coal) and total amount of CH4 or N2O is derived from
summing emissions from three different sources.
2.3 Future Greenhouse Gas Emission Scenario at Residential Zone of Dhaka City
At present Bangladesh government has already formulated the Renewable Energy Policy. The government has
decided to make mandatory installation of solar panels in case of high-rise buildings having more than 10 floors
(consumption level >2 kW) in Dhaka and other major cities in a bid to ease the nagging power crisis. If the
high-rise buildings could generate electricity of their own through the solar panels, the circular said, it would
reduce pressure on the national grid.At present in both south and north Dhaka certain number of solar panel has
been installed by DPDC and DESCO. In this paper, estimation of mitigation of green house gas emission from
the conventional power generation system is done where the system is assumed as facilitated by solar panel
facility. The estimation is conducted for the life span of a standard solar panel .The data regarding high rise
building approval for three recent fiscal year 2009-2010, 2010-2011, 2011-2012 is collected from RAJUK
database and information section.This data has been expanded for 25 individual year, which is the standard life
span of solar panel ,2009 to 2036 by polynomial extrapolation method. The calcultion is done theoretically
installing standard capacity solar panel in each high rise building and estimating their capacity.From measured
saved power by solar panel, estimation of greenhouse gas emission is conducted. This amount of greenhouse gas
would be emitted if the structure is not facilitated by solar panel facility. Thus the reduced emission by
installment of solar panel can be calculated.
3. ILLUSTRATIONS
3.1 GHG Emission From Conventional Power Generation Technology In FY 2010-11
Power consumption data of Dhaka city’s residential area in fiscal year 2010-11 is collected from two
organizations in Dhaka city who basically distributes power to the consumer. these two organization are:
Dhaka Power Distribution Company (DPDC)
Dhaka Electric Supply Company Limited (DESCO)
Total amount of power consumption of residential building of Dhaka city is 3658.125 MkWh. The calculation
of amount of fuel combustion is conducted indirectly from amount of power consumed at that area. The process
represents how much fuel actually combusted to produce consumed electricity by the residents of Dhaka city on
the particular year of 2010-11.before forwarding towards calculation we have to separate source wise electricity
generation.
As this Paper topic is concerned about fuel combustion from conventional power generation system so
estimation of emission has conducted for three natural fuel sources- natural gas, bituminous coal and oil.
Electricity production from natural gas sources ( % of total) = 89% =3255.73 MkWh
Electricity production from coal sources ( % of total)= 1.8%=6.58MkWh
Electricity production from oil sources ( % of total)=5 %=182.91 MkWh
The amount of carbon di oxide emission is measured using emission equation.
Estimated CO2 emitted from natural gas = 1.93×106
ton/year.
Estimated CO2 emitted from residual fuel oil =159.810×103
ton/year.
Estimated CO2 emitted from coal = 8787.99 ton/year.
Total amount of carbon di oxide emitted from three major sources (natura gas,bituminous coal, residual furnace
fuel oil) to produce electricity which has been distributed to the residential area of Dhaka city in FY 2010-11 is
2.1 × 106
ton/year.
Estimated Methane (CH ) emission from natural gas =36.42 ton/year
Estimated Methane (CH ) emission from fuel source oil = 6.084 ton/year
Estimated Methane (CH ) emission from fuel sourcebituminous coal = 0.094 ton/year
Total amount of methane gas (CH ) emitted from three major sources (natural gas, bituminous coal, residual
furnace fuel oil) to produce electricity which has been distributed to the residential area of Dhaka city in FY
2010-11 is 42.59 ton/year.
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Estimated Nitrous Oxide (N2O) emission from natural gas =3.642 ton/year
Estimated Nitrous Oxide (N2O) emission from fuel source oil = 1.22 ton/year
Estimated Nitrous Oxide (N2O) emission from fuel source bituminous coal = 0.15 ton/year
Total amount of nitrous oxide (N2O) emitted from three major sources (natural gas, bituminous coal, residual
furnace fuel oil) to produce electricity which has been distributed to the residential area of Dhaka city in FY
2010-11:
=5.012 ton/year
Final Result:
1.Total amount of carbon di oxide (CO2) emitted from three major sources is 2.1 × 106
ton/year.
2.Total amount of methane gas (CH ) emitted from three major sources is 42.59 ton/year
3.Total amount of nitrous oxide (N2O) emitted from three major is 5.012 ton/year
Table 3: Total GHG emission from conventional electricity generation in FY 2010-11
Emission(ton/year) Natural Gas Bituminous coal Furnace Oil
Total emission
(ton/year)
CO2 1.93×106
8787.99 159.810×103
2.1 × 106
CH4 36.42 0.094 6.084 42.59
N2O 3.642 0.15 1.22 5.012
3.2 Estimating Mitigation of Greenhouse Gas After Installing Solar Panel in a Residential Area of
Dhaka City in Fiscal Year 2010-11
The Government of Bangladesh is seeking to expand alternative energy sources as the domestic production of
natural gas is on the decline. The Energy Ministry has adopted a multitude of programs to mitigate the reliance
on natural gas. Expanding the use of renewable energy has been a major focus area. As a part of this initiative
the Energy Ministry has introduced a solar energy policy for the housing industry. This policy requires that all
newly constructed buildings must include a rooftop solar power unit with an output no less than 3% of the
building’s total peak load [2]. In fiscal year 2010-11 both two leading organization Dhaka Power Distribution
Company (DPDC) and Dhaka Electric Supply Company limited (DESCO) installed several number of solar
panels at the residential area of Dhaka city to lessen the load on conventional electricity supply system as well
as to meet the increasing demand of the electricity.After installing solar panel at various residential housing of
Dhaka city certain amount of electricity production from conventional power system has been reduced as well
as greenhouse gas emission. Electricity provided by solar panels is substituting that certain amount of electricity
that is supposed to be supplied by national power grid.The total amount of electricity derived from solar panel
facility can be assumed as substitution of conventional power system using natural gas as a fuel. Average
capacity of installed single solar panel at south Dhaka by DPDC 1.27 kW and at north Dhaka by DESCO is 0.87
kW in FY2010-11. So, assumed average capacity of hypothetically installed solar panel for reducing future
emissionis 1.07 kW. For Dhaka city, sun hour is 7.55 hour and activity time is 365 day [3]
The effect of installment of solar facility at rooftop of Dhaka city’s residential area on climate:
Mitigation of carbon di oxide CO2 = 1462.54 ton/year
Mitigation of methane CH4 =0.0276 ton/year
Mitigation of nitrous oxide N2O = 0.00276 ton/year.
This amount of mitigation is very negligible as it can reduce only small percentage of total emission. If we want
to mitigate green house gas emission by installing solar panel we really have to increase the number of solar
panel and their capacity.
3.3 Future GHG Emission Reduction Scenario After The Installment Of Solar Panels
Usually the standard life cycle of solar panel is 25 years. So for 25 years it will be capable for mitigating
greenhouse gas emission from conventional power generation plant indirectly. Every year certain amount of
high-rise building design has been approved by RAJUK. As per government policy it is now mandatory to
install solar panel at the roof top of newly constructed high-rise building to .So data has been collected about
recent three years building approval from RAJUK. These data is expanded for 25 years from 2009 to 2036 by
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polynomial extrapolation method. The total analysis is continued by hypothetically installing standard capacity
solar panel at each high-rise building and observing its impact on mitigation of greenhouse gas.Solar panel
reduces GHG emission. After installing solar panel in FY 2010-11 the GHG emission will be reduced for 25
years. This recovered future emission is shown in table 4.19. For the year 2013 sample calculation is shown:
Total approval of new building on year 2013 is 3812.
Capacity of newly installed solar panel only approved in that year is 4078.84 kW.
Total capacity of installed solar panel from the year 2009 to 2012 is 12409.86 kW
Thus, present capacity of all solar panel from the year 2009 to 2013 is 16488.7 kW
Total amount of electricity produced by this solar panel: 16488.7 kW×7.55 hour×365 days
= 45438735.03 kWh
Electricity produced using natural gas as a fuel source: 45438735.03 kWh
Amount of natural gas that was used to produce electricity:
= 45438735.03 kWh ×1000 ×0.01003 ft3
= 4.55×108 cubic feet.
= 4.55×108 scf/year
Using equation 1 and table 4.17, the yearly carbon di oxide emission potential was estimated.
Total amount of CO2 emitted =26899.39 ton/year
Following same procedure total reduction of methane and nitrous oxide gas can also be estimated for study
period of 25 year at Dhaka city. This recovered future emission is shown in table 4.
Table 4: Estimation of CO2 reduction throughout lifespan of standard solar panel
Year
Total
approval
of
Building
Capacity
of
installed
solar
panel
(kW)
Cumulative
Capacity of
installed
solar panel
(kW)
Total
kWh/year
Reduced
CO
emission
(ton/year)
2009 2333 2496.31 2496.31 6879206.283 4072.44
2010 2755 2947.85 5444.16 15002743.92 8881.51
2011 3063 3277.41 8721.57 24034466.53 14228.22
2012 3447 3688.29 12409.86 34198471.7 20245.24
2013 3812 4078.84 16488.7 45438735.03 26899.39
2014 4177 4469.39 20958.09 57755256.52 34190.68
2015 4542 4859.94 25818.03 71148036.17 42119.10
2016 4907 5250.49 31068.52 85617073.99 50684.66
2017 5272 5641.04 36709.56 101162370 59887.36
2018 5637 6031.59 42741.15 117783924.1 69727.19
2019 6002 6422.14 49163.29 135481736.4 80204.16
2020 6367 6812.69 55975.98 154255806.9 91318.27
2021 6732 7203.24 63179.22 174106135.5 103069.52
2022 7097 7593.79 70773.01 195032722.3 115457.90
2023 7462 7984.34 78757.35 217035567.3 128483.42
2024 7827 8374.89 87132.24 240114670.4 142146.07
2025 8192 8765.44 95897.68 264270031.7 156445.86
2026 8557 9155.99 105053.67 289501651.1 171382.79
2027 8922 9546.54 114600.21 315809528.7 186956.86
2028 9287 9937.09 124537.3 343193664.5 203168.06
2029 9652 10327.64 134864.94 371654058.4 220016.40
2030 10017 10718.19 145583.13 401190710.5 237501.87
2031 10382 11108.74 156691.87 431803620.8 255624.48
2032 10747 11499.29 168191.16 463492789.2 274384.23
2033 11112 11889.84 180081 496258215.8 293781.12
2034 11477 12280.39 192361.39 530099900.5 313815.14
2035 11842 12670.94 205032.33 565017843.4 334486.30
2036 12207 13061.49 218093.82 601012044.5 355794.59
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Figure 1 : Mitigation of CO2 emission throughout lifespan of solar panel
It is evident from figure 1 that the amount of recovered carbon di oxide emission will be increased with the
increment of building approval at Dhaka city.
Figure 2 : Mitigation of emission CH4 and N2O throughout lifespan of solar panel
In figure 2, reduction of emission CH4 and N2O throughout lifespan of solar panel is shown graphically. It is
seen that the proportion of nitrous oxide emission is very much low then methane emission. If the capacity and
number of solar panel at the roof top of Dhaka city are not increased, presently installed solar panel could not be
effective on reducing greenhouse gas emission in long run or throughout its life cycle. So big investment on
solar panel installment won’t be fruitful.
4. CONCLUSIONS
In Bangladesh, from the conventional electricity generation technologies huge amount of greenhouse gas emits
every year. Toxins and particulate matter are released during fossil fuel combustion. This emission has a
harmful effect on climate change. The major challenge for twenty-first century society is and will continue to be
the implementation of a global energy production infrastructure that can satisfy total demand, minimize cost,
produce as little pollution as possible and extend the lifetime of fossil fuels. Solar energy generated via solar
panels (also known as Photovoltaic Solar or PV solar) is one of the most sustainable ways we have of generating
energy and electricity today. This is one of the most sustainable energy systems which can lessen the increasing
demand of electricity at Dhaka city. First and foremost solar panels produce electricity without emissions of any
kind. Under the government plan to generate 5 percent of the power from renewable energy sources by 2014,
new buildings must install solar panels that could produce 3 percent of the total electricity need of a building
before getting any new power connection. To assess the decision taken by government this study presents a
detailed analysis on recovered emission scenario by solar systems. It was assumed that each of the buildings will
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be equipped with a standard capacity solar panel. After installing solar panel at various residential housing of
Dhaka city certain amount of electricity production from conventional power system was reduced as well as
GHG emission, because solar panel is substituting that certain amount of electricity that was supposed to be
supplied by national power grid. From measured saved power by solar panel, greenhouse gas emission was
estimated. This is the amount of greenhouse gas that would be emitted if the structure is not equipped with solar
panel.
4.1 Findings
A significant amount of GHG gas emitted and will emit from conventional electricity generation system.
It’s been shown in this study solar panel production releases much less CO2 and other greenhouse gases as
do electricity generated from coal, oil, natural gas, etc. Solar panel reduces emission from conventional
electricity generation technologies indirectly.Moreover, Over Greenhouse gas recovery project by installed solar
panel at Dhaka city in FY 2010-11 produce certified emission reductions that can be sold to global carbon
market. This emission trading will bring foreign investment that can enhance the solar panel installation practice
of Dhaka city. While some changes in the operation of the CDM could increase solar investment, the price of
carbon credits required to make solar energy technologies economically competitive with other technologies to
reduce GHG emissions would be high. To reduce GHG emission from electricity generation technologies which
were conventionally used in Bangladesh, more renewable energy alternatives are required besides solar panels
installation. So government should focus on other renewable energy technology.“Green Taxes”, are currently
being levied in various developed nations to balance the difference in cost of renewable and nonrenewable
electricity production. These taxes require power companies to pay per ton on emissions they generate. We can
estimate the potential of green tax which can be derived from the non-governmental and private power plant
which produce electricity for our country. Moreover it can enhance our economy as well as help to reduce
greenhouse emission mitigation. Careful monitoring of different components and accurate estimation of
emission is very important.The sun exposure is going to be different in other parts of the country, therefore this
report and its conclusions are ideal for only Dhaka city.
REFERENCES
[1] NCDAQ (2009), Greenhouse gas emission guidelines: Stationary combustion sources”, North Carolina
Division of Air Quality, pp 4, http://www.ncair.org
[2] REHAB (2012), “An Evaluation of 3% Roof Top Solar Panel Policy in Bangladesh”, Real Estate and
Housing Association of Bangladesh, Dhaka, Bangladesh.
[3] Eshita, S.T., Hossain, A. And Raihan, M.O. (2010), “Design and simulation of a solar PV system for BRAC
University, Department of Electrical and Electronics, BRAC University, Dhaka, Bangladesh -22.
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