‫ﺴﻢ ﷲ اﻟﺮﲪﻦ اﻟﺮﺣﲓ‬
University Of Khartoum
Faculty of Engineering
Agricultural and Biological Engineering Department
SOLAR ENERGY AS DOMESTIC
ELECTRICITY ALTERNATIVE IN HOUSES
A Thesis submitted in a partial fulfillment of the
requirement for the degree of B.Sc in Agricultural and
Biological Engineering
Presented By:
Lama Omer Abdulgaffar Omer
Under Supervision of:
Dr. Mohammed Abaker Ahmed
AUGUST 2015
I
Abstract
Humanity continues to increase in number and, despite major efforts towards improving the
efficiency of energy consumption, the overall per capita use of energy continues to increase.
Alternative energy encompasses all those things that do not consume fossil fuel. They are widely
available and environment friendly. They cause little or almost no pollution. There have been
several alternative energy projects running in various countries to reduce our dependence on
traditional fossil fuels. There are many impressive options that you can take into consideration.
Here in you will learn more about alternative energy sources that you can take into consideration.
Solar energy is one the alternative energy source that is used most widely across the globe.
About 70% of the sunlight gets reflected back into the space and we have only 30% of sunlight
to meet up our energy demands. A study has been performed to compare between two methods
of generating electricity in houses. It compares between conventional power generations sources
currently used to generate electricity in Sudanese houses and PV (Photovoltaic) system as an
alternative electricity source in economical way. Firstly, electricity consumption in three
different capacity levels houses (Low, Medium, and High), randomly chosen in Khartoum State
has been calculated using data from Ministry of Electricity and Dams, Electricity Distribution
Company. Secondly the design process for tree similar capacity PV powered houses has been
executed, and finally the last step was to make an economical comparison between two
mentioned methods of generating electricity in Sudanese houses. The study conclusion was that,
the, the total PV system cost per month is very close to the monthly cost of electricity, also PV
systems have a running cost advantages over the conventional electricity generation sources
through its life time, in addition, PV systems has no significant effects on environment.
I
‫اﻟﻤﺴﺘﺨﻠﺺ‬
‫ﯾﺴﺘﻤﺮ اﻟﺘﻌﺪاد اﻟﺴﻜﺎﻧﻲ ﻓﻲ اﻟﺰﯾﺎدة ﺑﺄﻋﺪاد ﻛﺒﯿﺮة‪ ،‬و ﺑﺎﻟﺮﻏﻢ ﻣﻦ اﻟﺠﮭﻮد اﻟﻤﺒﺬوﻟﺔ ﺗﺠﺎه ﺗﺮﺷﯿﺪ إﺳﺘﮭﻼك اﻟﻄﺎﻗﺔ‪ ،‬ﯾﻈﻞ ﻧﺼﯿﺐ اﻟﻔﺮد‬
‫ﻣﻦ إﺳﺘﺨﺪام اﻟﻄﺎﻗﺔ ﻓﻲ اﻹزدﯾﺎد اﻟﻤﻀﻄﺮد‪ .‬ﺗﺸﻤﻞ اﻟﻄﺎﻗﺔ اﻟﺒﺪﯾﻠﺔ ﻛﻞ ﺗﻠﻚ اﻷﺷﯿﺎء اﻟﺘﻲ ﻻ ﺗﺴﺘﮭﻠﻚ وﻗﻮد إﺣﻔﻮري‪ ،‬و ھﻲ ﻣﺘﻮﻓﺮة‬
‫ﺑﺼﻮرة واﺳﻌﺔ و ﺻﺪﯾﻘﺔ ﻟﻠﺒﯿﺌﺔ‪ ،‬و ﺗﻘﺮﯾﺒﺎً ﻟﯿﺲ ﻟﺪﯾﮭﺎ ﺗﺄﺛﯿﺮ ﯾﺬﻛﺮ ﻋﻠﻰ اﻟﺘﻠﻮث‪ .‬ھﻨﺎك اﻟﻌﺪﯾﺪ ﻣﻦ ﻣﺸﺎرﯾﻊ اﻟﻄﺎﻗﺎت اﻟﺒﺪﯾﻠﺔ اﻟﺘﻲ‬
‫ﺗﻌﻤﻞ ﻓﻲ اﻟﻜﺜﯿﺮ ﻣﻦ اﻟﺒﻠﺪان ﻟﺘﻘﻠﯿﻞ اﻹﻋﺘﻤﺎد ﻋﻠﻰ اﻟﻮﻗﻮد اﻹﺣﻔﻮري اﻟﺘﻘﻠﯿﺪي‪ ،‬و اﻟﺨﯿﺎرات ﻛﺜﯿﺮة و ﺟﻤﯿﻌﮭﺎ ﯾﻤﻜﻦ اﻹﺳﺘﻔﺎدة ﻣﻨﮭﺎ‪.‬‬
‫اﻟﻄﺎﻗﺔ اﻟﺸﻤﺴﯿﺔ ھﻲ إﺣﺪى ﺧﯿﺎرات اﻟﻄﺎﻗﺔ اﻟﺒﺪﯾﻠﺔ اﻟﺘﻲ ﯾﺘﻢ إﺳﺘﺨﺪاﻣﮭﺎ ﻋﻠﻰ ﻧﻄﺎق واﺳﻊ ﻣﻦ اﻟﻌﺎﻟﻢ‪ .‬ﺗﻘﺮﯾﺒﺎً ﺣﻮاﻟﻲ ‪ %70‬ﻣﻦ‬
‫اﻷﺷﻌﺔ اﻟﺸﻤﺴﯿﺔ اﻟﺴﺎﻗﻄﺔ ﻋﻠﻰ اﻷرض ﺗﻨﻌﻜﺲ راﺟﻌﺔ إﻟﻰ اﻟﻔﻀﺎء اﻟﺨﺎرﺟﻲ‪ ،‬و ﻓﻘﻂ ‪ %30‬ﻣﻦ اﻹﺷﻌﺎع اﻟﺸﻤﺴﻲ اﻟﻜﻠﻲ ھﻮ‬
‫اﻟﻤﺴﺘﺨﺪم ﻟﻤﺠﺎﺑﮭﺔ اﻟﻄﻠﺐ اﻟﻤﺘﺰاﯾﺪ ﻋﻠﻰ اﻟﻄﺎﻗﺔ‪ .‬أﺟﺮﯾﺖ دراﺳﺔ ﻟﻠﻤﻘﺎرﻧﺔ ﻣﻦ اﻟﻨﺎﺣﯿﺔ اﻹﻗﺘﺼﺎدﯾﺔ ﺑﯿﻦ أﻧﻈﻤﺔ ﺗﻮﻟﯿﺪ اﻟﻜﮭﺮﺑﺎء ﺷﺎﺋﻌﺔ‬
‫اﻹﺳﺘﺨﺪام ﻟﺘﻮﻟﯿﺪ اﻟﻜﮭﺮﺑﺎء ﻓﻲ اﻟﻤﻨﺎزل ) ﻣﺤﻄﺎت ﺗﻮﻟﯿﺪ اﻟﻜﮭﺮﺑﺎء اﻟﺒﺨﺎرﯾﺔ‪ ،‬اﻟﻐﺎزﯾﺔ‪ ،‬و اﻟﻤﺎﺋﯿﺔ( و ﻧﻈﺎم اﻟﺨﻼﯾﺎ اﻟﺸﻤﺴﯿﺔ ﻟﺘﻮﻟﯿﺪ‬
‫اﻟﻜﮭﺮﺑﺎء‪ .‬أوﻻً ﺗﻢ ﺣﺴﺎب إﺳﺘﮭﻼك اﻟﻜﮭﺮﺑﺎء ﻓﻲ ﺛﻼث ﻣﺴﺘﻮﯾﺎت ﻣﻦ اﻟﻤﻨﺎزل ذات ﺳﻌﺎت ﻣﺘﻔﺎوﺗﺔ )ﻣﻨﺨﻔﻀﺔ‪ ،‬ﻣﺘﻮﺳﻄﺔ‪ ،‬و ﻛﺒﯿﺮة(‬
‫ﺗﻢ إﺧﺘﯿﺎرھﺎ ﺑﻌﺸﻮاﺋﯿﺔ ﻣﻦ داﺧﻞ وﻻﯾﺔ اﻟﺨﺮﻃﻮم ﺑﺈﺳﺘﺨﺪام ﺑﯿﺎﻧﺎت ﻣﺄﺧﻮذة ﻣﻦ وزارة اﻟﻜﮭﺮﺑﺎء و اﻟﺴﺪود‪ ،‬ﺷﺮﻛﺔ ﺗﻮزﯾﻊ اﻟﻜﮭﺮﺑﺎء‬
‫اﻟﺴﻮداﻧﯿﺔ‪ .‬ﺛﺎﻧﯿﺎً ﺗﻢ إﻋﺪاد ﺗﺼﻤﯿﻢ ﻟﺜﻼث ﻣﻨﺎزل ﯾﺘﻢ ﺗﻮﻟﯿﺪ اﻟﻄﺎﻗﺔ ﻓﯿﮭﺎ ﺑﻮاﺳﻄﺔ اﻟﺨﻼﯾﺎ اﻟﺸﻤﺴﯿﺔ ﺑﻨﻔﺲ اﻟﺴﻌﺎت اﻟﻤﺬﻛﻮرة أﻋﻼه‪ ،‬و‬
‫أﺧﯿﺮاً أﺟﺮﯾﺖ ﻣﻘﺎرﻧﺔ إﻗﺘﺼﺎدﯾﺔ ﺑﯿﻦ ﺗﻜﻠﻔﺔ و ﺟﺪوى إﺳﺘﺨﺪام ﻛﻼ اﻟﻨﻈﺎﻣﯿﻦ ﻹﻣﺪاد اﻟﻤﻨﺎزل ﺑﻤﺨﺘﻠﻒ ﻣﺴﺘﻮﯾﺎﺗﮭﺎ ﺑﺎﻟﻜﮭﺮﺑﺎء اﻟﻼزﻣﺔ‪.‬‬
‫ﯾﺨﻠﺺ اﻟﺒﺤﺚ إﻟﻰ أن ﺗﻜﻠﻔﺔ ﻧﻈﺎم اﻟﺨﻼﯾﺎ اﻟﺸﻤﺴﯿﺔ أﻋﻠﻰ ﺑﻘﻠﯿﻞ ﺑﺎﻟﺸﻜﻞ اﻟﺬي ﻻ ﯾﺠﻌﻠﮭﺎ ﻣﻠﺤﻮﻇﺔ ﺑﺎﻟﻤﻘﺎرﻧﺔ ﻣﻊ ﺗﻜﻠﻔﺔ اﻟﻜﮭﺮﺑﺎء‬
‫اﻟﺤﺎﻟﯿﺔ‪ ،‬ﻛﻤﺎ أن اﻟﻨﻈﺎم اﻟﺸﻤﺴﻲ ﯾﺘﻤﺘﻊ ﺑﺘﻜﻠﻔﺔ ﺗﺸﻐﯿﻞ ﻣﻌﻘﻮﻟﺔ ﻣﻘﺎرﻧﺔ ﺑﻨﻈﺎﺋﺮه ﻣﻦ اﻷﻧﻈﻤﺔ اﻟﺘﻘﻠﯿﺪﯾﺔ ﻟﺘﻮﻟﯿﺪ اﻟﻜﮭﺮﺑﺎء‪ ،‬ھﺬا ﺑﺎﻹﺿﺎﻓﺔ‬
‫إﻟﻰ أن اﻟﻨﻈﺎم اﻟﺸﻤﺴﻲ ﻟﯿﺲ ﻟﺪﯾﮫ أي ﺗﺄﺛﯿﺮات ﻣﻠﺤﻮﻇﺔ ﻋﻠﻰ اﻟﺒﯿﺌﺔ‪.‬‬
‫‪II‬‬
Acknowledgement
Firstly, I would like to express my sincere gratitude to my advisor Dr. Mohammed Abaker
Ahmed For the continuous support of my B.Sc study and related research, for his patience,
motivation, and immense knowledge. His guidance helped me in all the time of research and
writing of this thesis. I could not have imagined having a better advisor and mentor for my B.Sc
study.
My sincere thanks also goes to Eng. Abuobeida from Ministry of Electricity and Dams, who
provided me an opportunity to join their team as intern, and who gave access to the laboratory
and research facilities. Without they precious support it would not be possible to conduct this
research.
Last but not the least, I would like to thank my family: my parents and to my brothers and sister
for supporting me spiritually throughout writing this thesis and my life in general.
III
Contents
Abstract ………………………………………………………………………………………... I
‫……………………………………………………………………………………… اﻟﻤﺴﺘﺨﻠﺺ‬.. II
Acknowledgement ……………………………………………………………………………. III
List of Tables ………………………………………………………………………………. VIII
List of Figures ………………………………………………………………………………… IX
1. Introduction ………………………………………………………………………………… 1
1.1 Introduction …………………………………………………………………………….. 1
1.2 Feasibility of using solar energy in Sudan ……………………………………………... 1
1.3 Objectives of the study …………………………………………………………………. 4
2. Literature Review …………………………………………………………………………... 5
2.1 Energy ………………………………………………………………………………….. 5
2.1.1 Concept of energy ………………………………………………………………... 5
2.1.2 Energy systems …………………………………………………………………... 6
2.1.3 Conventional energy sources …………………………………………………….. 6
2.1.3.1 Coal ………………………………………………………………………. 6
2.1.3.2 Natural gases ……………………………………………………………... 7
2.1.3.3 Electricity ………………………………………………………………… 7
2.1.4 Winds of change in energy resources ……………………………………………. 7
2.1.5 Alternative energy resources …………………………………………………….. 8
2.1.5.1 Solar energy ……………………………………………………………… 8
2.1.5.2 Wind energy ……………………………………………………………… 9
2.1.5.3 Biomass energy ………………………………………………………….. 10
IV
2.1.5.4 Geothermal energy ………………………………………………………. 11
2.1.5.5 Hydroelectric energy …………………………………………………….. 13
2.1.5.6 Biofuel energy …………………………………………………………… 14
2.1.6 Why renewable energy …………………………………………………………... 14
2.1.6.1 Little to no global warming emissions …………………………………... 15
2.1.6.2 Improved public health and environmental quality …………………........ 15
2.1.6.3 A vast and inexhaustible energy supply …………………………………. 15
2.1.6.4 Jobs and other economic benefits ………………………………………... 16
2.1.6.5 Stable energy prices ……………………………………………………... 16
2.1.6.6 A more reliable and resilient energy systems …………………………… 17
2.2 Solar energy..................................................................................................................... 18
2.2.1 Historical review ………………………………………………………………… 18
2.2.2 Sun and solar radiation …………………………………………………………... 18
2.2.2.1 Earth motion around the sun …………………………………………….. 18
2.2.3 Solar energy technologies ……………………………………………………….. 19
2.2.3.1 Architecture and urban planning ………………………………………… 19
2.2.3.2 Agriculture and Horticulture …………………………………………...... 21
2.2.3.3 Transport ……………………………………………………………….... 21
2.2.3.4 Solar Thermal ……………………………………………………………. 22
2.2.3.4.1 Early commercial adaption …………………………………….. 22
2.2.3.4.2 Water heating …………………………………………………... 22
2.2.3.4.3 Heating, Cooling and Ventilating ……………………………… 23
2.2.3.4.4 Cooking ………………………………………………………… 24
2.2.3.4.5 Process heat …………………………………………………….. 25
2.2.3.4.6 Water treatment ………………………………………………… 25
V
2.2.3.5 Electricity production …………………………………………………….. 26
2.2.3.5.1 Photovoltaic …………………………………………………….. 27
2.2.3.5.2 Concentrated solar power ………………………………………. 27
2.2.3.6 Fuel production …………………………………………………………… 28
2.2.3.7 Energy storage methods …………………………………………………... 28
2.3 The Solar cell …………………………………………………………………………… 29
2.3.1 The cell basic Construction ………………………………………………………. 30
2.3.1.1 How does it work? ………………………………………………………... 30
2.3.1.2 Photovoltaic cells materials ………………………………………………. 32
2.3.1.2.1 Crystalline silicon …………………………………………......... 32
2.3.1.2.2 Thin film ……………………………………………………....... 33
2.3.1.2.3 Multijunction cells ……………………………………………… 34
2.3.2 Current development …………………………………………………………….... 35
2.3.3 Advance in energy storage ………………………………………………………... 35
2.4 The solar battery...…………………………………………………………….................. 36
2.5 The solar inverter ………………………………………………………………………... 37
2.6 The solar system wiring ………………………………………………………………..... 38
2.7 Solar energy in Sudan ………………………………………………………………….... 39
2.7.1 Solar radiation in Sudan …………………………………………………………… 39
2.7.2 Latest solar photovoltaic research work in Sudan ……………………………….... 39
3. Material and Methods ……………………………………………………………………….. 40
3.1 Introduction ……………………………………………………………………………… 40
3.2 Electricity consumption in houses ………………………………………………………. 40
3.3 Global Radiation ……………………………………………………………………….... 40
3.4 PV (Photovoltaic) system power consumption equation ………………………………... 41
VI
3.5 Selection of battery …………………………………………………………………….... 41
3.6 Inverter capacity ………………………………………………………………………… 42
4. Result and Discussion ……………………………………………………………………….. 43
4.1 Results ………………………………………………………………………………….... 43
4.1.1 Global radiation calculation ……………………………………………………….. 43
4.1.2 Low level calculations …………………………………………………………….. 44
4.1.2.1 Low level electricity consumption calculations …………………………... 44
4.1.2.2 PV (Photovoltaic) system design for low level ………………………….... 44
4.1.3 Medium level calculations ……………………………………………………….... 46
4.1.3.1 Medium level electricity consumption calculations ………………………. 46
4.1.3.2 PV (Photovoltaic) system design for medium level ……………………..... 47
4.1.4 High level calculations ………………………………………………………......... 48
4.1.4.1 High level electricity consumption calculations ………………………….. 48
4.1.4.2 PV (Photovoltaic) system design for high level …………………………... 49
4.1.5 PV (Photovoltaic) system estimated cost ……………………………..................... 50
4.1.5.1 Price list ………………………………………………………………….... 50
4.1.5.2 Initial cost calculations for solar houses …………………….…………….. 50
4.1.5.3 Full operational life time cost ……………………………………………... 51
4.1.6 Electricity cost estimation …..................................................................................... 53
4.2 Discussion ……………………………………………………………………………….. 53
5. Conclusion and Recommendations ………………………………………………………….. 54
5.1 Conclusion ………………………………………………………………………………. 54
5.2 Recommendations ……………………………………………………………………….. 54
References………………………………………………………………………………………. 55
VII
List of Tables
Table 4.1 Global Radiation Throughout the year in Sudan ……………………………............. 41
Table 4.2 Electricity Consumption for low level ……………………………………………… 42
Table 4.3 Electricity Consumption for medium level …………………………………………. 43
Table 4.4 Electricity Consumption for high level ……………………………………………... 45
Table 4.5 PV Systems Design Summary ……………………………………………………… 46
Table 4.6 Prices for PV System components ………………………………………………….. 47
Table 4.7Power Requirements for PV (Photovoltaic) System Components ………………….. 47
Table 4.8 PV Systems Cost Estimation ………………………………………………………... 48
Table 4.9 Comparison between electricity cost and PV system total cost …………………….. 49
VIII
List of Figures
Fig 1.1 Electric power consumption (kWh per capita) in Sudan ………………………………... 4
Fig. 2.1 total world energy consumption by source (2010) ……………………...……………… 6
Fig. 2.2 Solar energy as an alternative source of energy …………………………………...…...10
Fig. 2.3 wind energy working phases ………………………………………………………….. 11
Fig. 2.4 Biomass energy extraction from its primary sources …………………………………. 12
Fig. 2.5 Electricity generation from geothermal energy sources ………………………………. 13
Fig. 2.6 Hydroelectric energy power plant …………………………………………………….. 14
Fig. 2.7 life cycle of producing Biofuel ……………………………………………………….. 15
Fig. 2.8 Sun-earth relationships ……………………………………………………………….. 20
Fig. 2.9Darmstadt University of Technology, Germany, won the 2007 Solar Decathlon
In Washington, D.C. with this passive house designed for humid and hot subtropical climate
…………………………………………………………………………………………………. 21
Fig. 2.10 Green houses like these in the Westland municipality of the Netherlands grow
Vegetables, fruits and flowers ………………………………………………………………… 22
Fig. 2.11Winner of the 2013 World Solar Challenge in Australia …………………………… 23
Fig. 2.12 Solar water heaters facing the Sun to maximize gain ………………………………. 24
Fig. 2.13 Solar House, used seasonal thermal energy storage for year-round heating ……….. 25
Fig. 2.14 Parabolic dish produces steam for cooking, in Auroville, India …………………… 26
IX
Fig. 2.15 Solar water disinfection in Indonesia ………………………………………………. 27
Fig. 2.16 some of the world's largest solar power stations: Ivanpah (CSP) and Topaz (PV)
………………………………………………………………………………………………… 28
Fig. 2.17Thermal energy storage. The Andasol CSP plant uses tanks of molten salt to store
Solar energy …………………………………………………………………………………… 29
Fig. 2.18 Solar Cell produce electricity directly from sunlight ………………………………. 31
Fig. 2.19 A working scheme of how solar works …………………………………………….. 32
Fig. 2.20 the charge controller is the heart of any solar power system like this. It takes the
Power from the solar panels and charges the battery in a precisely controlled way ………….. 37
Fig. 2.21 SMA Solar Inverter …………………………………………………………………. 38
Fig. 2.22 a typical 2 Kilowatts solar system wiring diagram …………………………………. 38
X
Chapter One
Introduction
XI
1. Introduction
1.1 Introduction
Humanity continues to increase in number and, despite major efforts towards improving the
efficiency of energy consumption, the overall per capita use of energy continues to increase.
Projections conceding the human population and its energy requirements during the next century
estimate populations in excess of seven billion and energy consumption per person in excess of
40,000 kilowatt hours per year (approximately twice the current rate). This increasing energy use
must be viewed in the light of the finite availability of conventional energy sources. When done
so the energy crisis can be seen to be all too real for any long term comfort.
A frequently mentioned solution to the problem of increasing requirements for energy and
dwindling energy sources is to tap the energy in sunlight. The solar energy falling on the earth's
surface each year is over 20,000 times the amount presently required by the human race, making
for a seemingly inexhaustible supply. For effective utilization of any energy source civilization
requires an easily storable, easily transportable form of energy (after all, it is dark at night). This
implies that the incoming solar energy should be transformed into electrical energy. In tum this
means that we need to utilize photovoltaic (solar cell) conversion of the energy in sunlight.[6]
Despite of the electricity cost of solar PV (Photovoltaic) system is relatively high compared to
other conventional power generation sources, but the solar PV (Photovoltaic) system has a costcutting over time.
Although the cost of energy produced from conventional energy source is low, but it comes with
a very high environmental costs. Emissions from these sources contribute heavily on climate
change resulting in significant health and economic consequences for diverse communities
through the world. Since these resources are limited, they will not provide a secure future energy
supplies for the world.
1.2 Feasibility of using Solar Energy in Sudan
Spread across central Africa as the continent's largest country, Sudan plans to exploit the
relentless Saharan sun to power its underdeveloped regions and green its deserts.
Harnessing the sun's energy for vast regions such as war-torn Darfur, which itself is the size of
France, is costly. But the country's ministry of energy and mining believes that advances in solar
technology will lower the costs.
1
"The costs are high compared to other conventional energy resources but we think that with the
technology advances going on there will be a substantial decrease," the ministry's secretary
general, Omar Mohammed Kheir, told AFP.The plan, he said, was to develop solar energy in
regions not linked to the national grid, such as North Darfur.By harnessing clean solar power
impoverished Sudan could be setting a global example in a world worried about climate change.
Sudan is the continent's fifth largest oil producer -- three fifths of its product is exported to Asia - and is multiplying its hydroelectric projects along the Nile.But conventional energy sources
alone will not meet the increasing demand of this country of 40 million people.
"Our country is developing very, very fast and we think there is a need for more electricity. That
is why we have a master plan to generate about 20.000 megawatts within the coming 20 years,"
Kheir said.
"The hydro power may contribute to 20 to 25 percent at maximum. The rest will come from
other sources, all renewable energy including biofuel, solar energy, gas and maybe even nuclear
energy."Sudan has already launched a plant to produce biofuels, with a target of two million
liters (528,000 gallons) in two years.
Marc Benmarraze, chairman of Solar Euromed, said Sudan was well placed to use solar energy,
but he cautioned over the country's conflict-ridden history."Sudan is in the zone known as the
solar belt, where there is a direct normal radiation that is one of the world's strongest,"
Benmarraze said.
The company's first project will produce at least 150 megawatts with up to a third generated by
solar power.The agreement, though in its basic stages, could be a first step in ambitious plans to
green the deserts in northern Sudan and North Darfur.
"In this region, desertification has happened," said Osama Rayis with the African City of
Technology, which is linked to the ministry of technology."So our idea is turning yellow to
green, through the use of solar energy for pumping because there is a lot of underground water in
all these areas, so we can change the picture dramatically," he said."It is very difficult to use
fossil-based energy there because transportation is a problem," he said.
But costs stand in the way."Our problem is the lack of funds. So we are trying to work it out," he
said. "We are trying to market these projects for the parties, the government, the international
community, NGOs."
Investing in the conflict ridden country, which went from a two-decade civil war between the
north and the south to a devastating war in Darfur, is risky.Sudan "has its own political risks,"
2
said Benmarraze, adding it was necessary to take it "step by step" rather than try to secure the
full 10-billion needed for the project.
Ulrich Mans, a renewable energy specialist at Amsterdam University visiting Sudan for research,
said it was necessary to show that the technology would work in the country to gain investors'
confidence."In order to get significant investors on board it is crucial to show that this
technology makes economic sense and offers returns on investment to foreign companies," he
added. [22]
Until the second half of 2008, Sudan's economy boomed on the back of increases in oil
production, high oil prices, and large inflows of foreign direct investment. GDP growth
registered more than 10% per year in 2006 and 2007. From 1997 to date, Sudan has been
working with the IMF to implement macroeconomic reforms, including a managed float of the
exchange rate. Sudan began exporting crude oil in the last quarter of 1999. Agricultural
production remains important, because it employs 80% of the work force and contributes a third
of GDP. The Darfur conflict, the aftermath of two decades of civil war in the south, the lack of
basic infrastructure in large areas, and a reliance by much of the population on subsistence
agriculture ensure much of the population will remain at or below the poverty line for years
despite rapid rises in average per capita income.[23]
Electric power consumption (kWh per capita) in Sudan was last measured at 143.45 in 2011,
according to the World Bank. Electric power consumption measures the production of power
plants and combined heat and power plants less transmission, distribution, and transformation
losses and own use by heat and power plants. This page has the latest values, historical data,
forecasts, charts, statistics, an economic calendar and news for Electric power consumption
(kWh per capita) in Sudan.[24]
Fig 1.1 Electric power consumption (kWh per capita) in Sudan.
3
1.3 Objectives of the Study:
The objectives of this project are:
(1) Study the electricity domestic consumption at a selected area in Khartoum state.
(2) Study the potential of solar electricity generation in the selected area.
(3) Compare the cost of electricity from PV (Photovoltaic) systems and National grid.
4
Chapter Two
Literature
Review
5
2. Literature Review
2.1 Energy
2.1.1 Concept of Energy:
Energy is one of the most fundamental parts of our universe. We use energy to do work. Energy
lights our cities. Energy powers our vehicles, trains, planes and rockets. Energy warms our
homes, cooks our food, plays our music, and gives us pictures on television. Energy powers
machinery in factories and tractors on a farm.
Energy from the sun gives us light during the day. It dries our clothes when they're hanging
outside on a clothes line. It helps plants grow. Energy stored in plants is eaten by animals, giving
them energy. And predator animals eat their prey, which gives the predator animal energy.
Everything we do is connected to energy in one form or another. Energy is defined as: "the
ability to do work."[8]
The sources of energy available to mankind on this planet are commonly divided into two broad
categories: (1) energy capital sources, i.e., those sources of energy which, once used, cannot be
replaced on any time scale less than millions of years (details to follow); and (2) energy income
sources, i.e. those sources of energy which are more or less continuously refreshed (by nature or
by man assisting nature) and which may be considered to be available, at potentially their current
levels of supply, for millions of years.[7]
Fig. 2.1 total world energy consumption by source (2010).
5
Source:https://www.google.com/search?q=solar+energy+images&tbm=isch&tbo=u&source=uni
v&sa=X&ved=0CDMQsARqFQoTCO72hvT7tscCFQVTkgodpaQETw#tbm=isch&q=biomass+
energy+images&imgrc=zaAqSq7u4I2oiM%3A
2.1.2 Energy Systems:
Energy engineering or Energy systems is a broad field of engineering dealing with energy
efficiency, energy services, facility management, plant engineering, environmental compliance
and alternative energy technologies. Energy engineering is one of the more recent engineering
disciplines to emerge. Energy engineering combines knowledge from the fields of physics, math,
and chemistry with economic and environmental engineering practices. Energy engineers apply
their skills to increase efficiency and further develop renewable sources of energy. The main job
of energy engineers is to find the most efficient and sustainable ways to operate buildings and
manufacturing processes. Energy engineers audit the use of energy in those processes and
suggest ways to improve the systems. This means suggesting advanced lighting, better
insulation, more efficient heating and cooling properties of buildings.[1] Although an energy
engineer is concerned about obtaining and using energy in the most environmentally friendly
ways, their field is not limited to strictly renewable energy like hydro, solar, biomass, or
geothermal. Energy engineers are also employed by the fields of oil and natural gas extraction.
[1][2]
2.1.3 Conventional Energy Sources:
The conventional sources of energy are generally non-renewable sources of energy, which are
being used since a long time. These sources of energy are being used extensively in such a way
that their known reserves have been depleted to a great extent.
At the same time it is becoming increasingly difficult to discover and exploit their new deposits.
It is envisaged at known deposits of petroleum in our country will get exhausted by the few
decades and coal reserves are expected to last for another hundred years. The coal, petroleum,
natural gas and electricity are conventional sources of energy.
2.1.3.1 Coal:
Coal is one of the most important sources of energy and is being used for various proposes such
as heating of housed, as fuel for boilers and steam engines and for generation of electricity by
thermal plants.
Coal has also become a precious source of production of chemical of industrial importance coal
is and will continue to be the mainstay of power generation in India. It constitutes about 70% of
total commercial energy consumed in the country.
6
Oil and Natural gases like coal, petroleum is also derived from plants and also from dead animals
that lived in remote past. Natural gas has also been produced in the Earth's curst by the similar
process as petroleum and this is also a combustible fuel.
The exploitation of oil on a large scale started after 1960, the year when the first commercial
well is reported to have come into existence. In India, efforts made by the Oil and Natural Gas
Corporation since the late 1950s have led to the identification of a number of oil and gas deposits
both offshore and onshore.
2.1.3.2 Natural Gases:
Natural gas is also emerging as an important source of energy in India's commercial energy
scene in view of large reserves of gas that have been established in the country, particularly, in
South Bassein off west coast of India. Natural gas in also making significant contribution to the
household sector.
About 30% of the country's output of LPG comes from this source. About three- fourths as the
total gas comes from Mumbai high and rest is obtained from Gujarat, Andhra Pradesh, Assam
Tamil Nadu and Rajasthan. The Oil and Natural Gas Corporation has made a significant hydro
carbon finding and Reliance Industries struck gas off the Orissa coast in Bay of Bengal.
2.1.3.3 Electricity:
Electricity is another conventional source of power, which is playing a barometer of a nation's
economic well-being. Availability of abundant electricity means unrestricted growth of
industries, transport and agriculture.
There are various sources from which electricity is being produced. Depending upon raw
material used, there are three types of electricity (1) Hydroelectricity (ii) Thermal electricity
(steam, gas, oil) (iii) Nuclear electricity. [3]
2.1.4 Winds of Change in Energy Resources:
We are at the beginning of a structural change of our economic system. This change will be
triggered by declining fossil fuel supplies and will influence almost all aspects of our daily life.
Climate change will also force mankind to change the energy consumption pattern away from
fossil fuel combustion. This is a very serious problem. However, the focus of this contribution is
on resource depletion aspects, as these are much less transparent toothed public. The following
scenarios try to figure out if the present resource depletion problem eventually could be mastered
just by increasing the extraction rate of other conventional energy sources.
This transition period probably has its own rules which are valid only during this phase. Things
might happen which we have never experienced before and which we may never experience
7
again once this transition period is over. Specifically our way of dealing with energy topics may
change completely, which will have consequences for our economic systems.
The International Energy Agency (IEA) denies that such a fundamental change of our energy
supply is likely to happen in the near or medium-term future and therefore does not give a
warning that our economic system is in danger. Therefore the views of the IEA are briefly
analyzed. It will be shown that the ‘business as usual’ approach of the biennially published
World Energy Outlook does not describe our energy future appropriately.
After that the main drivers determining the transition to a changing energy future are discussed.
It is important to understand that we are entering such a transition period, leading to fundamental
changes. The acknowledgement of this development and the resulting mindset are necessary
preconditions for coping with this situation in an appropriate way. This will lead to completely
different behavior on the part of individuals, companies and governments. The imminent
transition is not a voluntary act in which people might or might not engage because changing
boundary conditions will force us to adapt our energy system and also our way of life. [6]
2.1.5 Alternative Energy Sources:
Alternative energy encompasses all those things that do not consume fossil fuel. They are widely
available and environment friendly. They cause little or almost no pollution. There have been
several alternative energy projects running in various countries to reduce our dependence on
traditional fossil fuels. There are many impressive options that you can take into consideration.
Here in you will learn more about alternative energy sources that you can take into consideration.
2.1.5.1 Solar Energy:
Solar is the first energy source in the world. It was in use much earlier before humans even learn
how to light a fire. Many living things are dependent on solar energy from plants, aquatic life
and the animals. The solar is mostly used in generating light and heat. The solar energy coming
down to the planet is affected by the orbital path of the sun and its variations within the galaxy.
In addition, it is affected by activity taking place in space and on the sun. It was this energy that
is believed to have been responsible for the breaking of ice during the ice age, which creates the
separation of lands and sea.
Solar energy is one the alternative energy source that is used most widely across the globe.
About 70% of the sunlight gets reflected back into the space and we have only 30% of sunlight
to meet up our energy demands. While solar energy is used for producing solar energy, it is also
used for drying clothes, used by plants during the process of photosynthesis and also used by
human beings during winter seasons to make their body temperature warm.
8
Fig. 2.2 Solar energy as an alternative source of energy.
There are two kinds of solar energy the active solar energy and the passive solar energy. Passive
solar energy basically uses duration, position and sun’s ray’s intensity to its advantage in heating
a particular area. It also uses it to induce airflow from an area to the next. Active solar energy
uses electrical technology and mechanical technology like collection panels in capturing,
converting and storing of energy for future use.
Solar energy does not create any pollution and is widely used by many countries. It is renewable
source of power since sun will continue to produce sunlight all the years. Solar panels, which are
required to harness this energy can be used for long time and require little or no maintenance.
Solar energy proves to be ineffective in colder regions which don’t receive good sunlight. It
cannot be used during night and not all the light from sun can be trapped by solar panels. Solar
energy advantages are much more than its disadvantages which make it as a viable source of
producing alternative energy.
2.1.5.2 Wind Energy:
This is one of the energy sources that have been in use for a very long time and for centuries. It
was used in powering sailing ships, which made it possible for explorers to sail around their
trade routes in distant lands. A single windmill can power the crop irrigation, and the family
energy needs, water pumping and electric lights. However, in the present time there are several
windmills that are used to generate required energy mostly for industrial uses. Many of the wind
turbines can capture much power all at once before feeding it to the power grid. This is
9
commonly known as wind farms and has been in use for many years all round the world. It is
only the United States that is going slow in terms of accepting this alternative energy source.
Wind power is renewable source of energy and reduces our alliance on foreign countries for
supply of oil and gas. It does not cause any air pollution and have created several jobs in last few
decades. Advancement in technologies has brought down the cost of setting up wind power
plant. Wind energy can only be used in areas which experience high winds which mean that it
cannot be used as a source to extract energy anywhere on earth. They sometimes create noise
disturbances and cannot be used near residential areas. These disadvantages have made the use
of wind energy to particular regions only.
Fig. 2.3 wind energy working phases.
Source:https://www.google.com/search?q=solar+energy+images&tbm=isch&tbo=u&source=uni
v&sa=X&ved=0CDMQsARqFQoTCO72hvT7tscCFQVTkgodpaQETw#tbm=isch&q=wind+ene
rgy+images&imgrc=CMDGaJgFonv11M%3A
2.1.5.3 Biomass Energy:
This is the process by which an alternative energy is generated through conversion of biological
materials and wastes into forms that can be used as energy sources for heating, power generation
and transportation. Those carbon based substances or materials converted over a long period of
10
time to fossil fuels are not regarded as biomass. However, in their original state they are regarded
as biomass. This is because of the separation of the carbon they previously contained from the
carbon cycle. This makes them figure differently affecting carbon dioxide levels in air.
Biomass energy has been around since ancient times when people use to burn wood or coal to
heat their homes or prepare food. Wood still remains the most common source to produce
biomass energy. Apart from wood, the other products that are used to create biomass energy
include crops, plants, landfills, municipal and industrial waste, trees and agricultural waste.
Biomass is renewable source of energy as we would be able to produce it as long as crops, plants
and waste exist. It does not create any greenhouse gases and is can be easily extracted through
the process of combustion. Another advantage of biomass is that it helps to reduce landfills.
Biomass is comparatively ineffective as compared to fossil fuels. They release methane gases
which can be harmful to the environment.
Fig. 2.4 Biomass energy extraction from its primary sources.
2.1.5.4 Geothermal Energy:
‘Geo’ means Earth and ‘thermal’ means energy. Geothermal energy means energy drawn or
harnessed from beneath the earth. It is completely clean and renewable. Geothermal energy has
been in used since last several years. The earth contains a molten rock called magma. Heat is
continuously produced from there. The temperature increases about 3 degrees Celsius, for every
100 meters you go below ground. Below, 10,000 meters the temperature is so high, that it can be
11
used to boil water. Water makes its way deep inside the earth and hot rock boils that water. The
boiling water then produces steam which is captured by geothermal heat pumps. The steam turns
the turbines which in turn activates generators. Read more about working of geothermal energy
here.
Geothermal energy can be found anywhere on the earth. Most countries tap this energy to
generate electricity and power millions of homes. The areas which have high underground
temperatures are the ones which are the ones which are prone to earthquakes and volcanoes. The
United States produces more Geothermal electricity than any other country in the world. Most
hot water geothermal reservoirs are located in the western states, Alaska, and Hawaii.
Geothermal energy is totally renewable as earth will continue to produce heat as long as we are
all are here. If these resources are tapped and are utilized effectively, they can provide solution to
the world’s power problems.
Geothermal energy produces no pollution, reduces our alliance on fossil fuels. It also results in
significant cost savings as no fuel is required to harness energy from beneath the earth. These
advantages make geothermal energy as one the best alternative energy source. But, geothermal
has its downsides too. It is suitable to particular region and cannot be harnessed everywhere. The
earth may release some harmful gases while releasing the heat which may prove adverse from
mankind. Also, the areas where this energy is harnessed are prone to earthquakes and volcanoes.
Apart from that, setting up of geothermal power stations requires huge installation cost. Here are
some pros and cons of geothermal energy.
Fig. 2.5 Electricity generation from geothermal energy sources.
12
Source:https://www.google.com/search?q=solar+energy+images&tbm=isch&tbo=u&source=uni
v&sa=X&ved=0CDMQsARqFQoTCO72hvT7tscCFQVTkgodpaQETw#tbm=isch&q=geotherm
al+energy+images&imgrc=x2Ej5BcIsztBtM%3A
2.1.5.5Hydroelectric Energy
Solar energy is produced by sun and wind energy is produced by moving of winds. The heat
caused by sun drives the wind. The movement of winds is then captured by wind turbines. Both
wind and sun cause water to evaporate. The water vapor then turns into rain or snow and flows
down to sea or oceans through rivers or streams. The energy of the moving water can then be
captured and called as hydroelectric power. Hydroelectric power stations capture the kinetic
energy of moving water and give mechanical energy to turbines. The moving turbines then
convert mechanical energy into electrical energy through generators. Dams around the world
have been built for this purpose only. Hydropower is the largest producer of alternative energy in
the world.
There are different types of hydropower plants. The selection of hydropower plant depends on
many volume and flow of water. Hydropower is renewable, constant, predictable and
controllable source of energy. They emit no greenhouse gases and are environment friendly. On
the negative side, they may cause adverse effect on aquatic life, reduce flow of water which may
affect agriculture, require huge costs to build and may cause havoc if they get breakdown. [4]
Fig. 2.6 Hydroelectric energy power plant.
Source:https://www.google.com/search?q=solar+energy+images&tbm=isch&tbo=u&source=uni
v&sa=X&ved=0CDMQsARqFQoTCO72hvT7tscCFQVTkgodpaQETw#tbm=isch&q=hydroelec
tric+energy+images&imgrc=eNzqL9nAAgVINM%3A
13
2.1.5.6 Biofuel Energy
A biofuel is a fuel that is produced through contemporary biological processes, such as
agriculture and anaerobic digestion, rather than a fuel produced by geological processes such as
those involved in the formation of fossil fuels, such as coal and petroleum, from prehistoric
biological matter. Biofuels can be derived directly from plants, or indirectly from agricultural,
commercial, domestic, and/or industrial wastes. Renewable biofuels generally involve
contemporary carbon fixation, such as those that occur in plants or microalgae through the
process of photosynthesis. Other renewable biofuels are made through the use or conversion of
biomass (referring to recently living organisms, most often referring to plants or plant-derived
materials). This biomass can be converted to convenient energy containing substances in three
different ways: thermal conversion, chemical conversion, and biochemical conversion. This
biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can also be
used directly for biofuels. [5]
Fig. 2.7 life cycle of producing Biofuel.
2.1.6 Why Renewable Energy:
Renewable energy — wind, solar, geothermal, hydroelectric, and biomass — provides
substantial benefits for our climate, our health, and our economy.
Each source of renewable energy has unique benefits and costs; this section explores the many
benefits associated with these energy technologies.
14
2.1.6.1 Little to No Global Warming Emissions:
Human activity is overloading our atmosphere with carbon dioxide and other global warming
emissions, which trap heat, steadily drive up the planet’s temperature, and create significant and
harmful impacts on our health, our environment, and our climate.
According to data aggregated by the International Panel on Climate Change, life-cycle global
warming emissions associated with renewable energy—including manufacturing, installation,
operation and maintenance, and dismantling and decommissioning—are minimal.
Compared with natural gas, which emits between 0.6 and 2 pounds of carbon dioxide equivalent
per kilowatt-hour (CO2E/kWh), and coal, which emits between 1.4 and 3.6 pounds of
CO2E/kWh, wind emits only 0.02 to 0.04 pounds of CO2E/kWh, solar 0.07 to 0.2, geothermal
0.1 to 0.2, and hydroelectric between 0.1 and 0.5. Renewable electricity generation from biomass
can have a wide range of global warming emissions depending on the resource and how it is
harvested. Sustainably sourced biomass has a low emissions footprint, while unsustainable
sources of biomass can generate significant global warming emissions.
2.1.6.2 Improved Public Health and Environmental Quality:
Generating electricity from renewable energy rather than fossil fuels offers significant public
health benefits. The air and water pollution emitted by coal and natural gas plants is linked to
breathing problems, neurological damage, heart attacks, and cancer. Replacing fossil fuels with
renewable energy has been found to reduce premature mortality and lost workdays, and it
reduces overall healthcare costs. The aggregate national economic impact associated with these
health impacts of fossil fuels is between $361.7 and $886.5 billion, or between 2.5 percent and 6
percent of gross domestic product (GDP).
Wind, solar, and hydroelectric systems generate electricity with no associated air pollution
emissions. While geothermal and biomass energy systems emit some air pollutants, total air
emissions are generally much lower than those of coal- and natural gas-fired power plants.
In addition, wind and solar energy require essentially no water to operate and thus do not pollute
water resources or strain supply by competing with agriculture, drinking water systems, or other
important water needs. In contrast, fossil fuels can have a significant impact on water resources.
2.1.6.3 A Vast and Inexhaustible Energy Supply:
Throughout the United States, strong winds, sunny skies, plant residues, heat from the earth, and
fast-moving water can each provide a vast and constantly replenished energy resource supply.
These diverse sources of renewable energy have the technical potential to provide all the
electricity the nation needs many times over.
15
Estimates of the technical potential of each renewable energy source are based on their overall
availability given certain technological and environmental constraints. However, it is important
to note that not all of this technical potential can be tapped due to conflicting land use needs, the
higher short-term costs of those resources, constraints on ramping up their use such as limits on
transmission capacity, barriers to public acceptance, and other hurdles.
2.1.6.4 Jobs and Other Economic Benefits
Compared with fossil fuel technologies, which are typically mechanized and capital intensive,
the renewable energy industry is more labor-intensive. This means that, on average, more jobs
are created for each unit of electricity generated from renewable sources than from fossil fuels.
In addition to the jobs directly created in the renewable energy industry, growth in renewable
energy industry creates positive economic “ripple” effects. For example, industries in the
renewable energy supply chain will benefit, and unrelated local businesses will benefit from
increased household and business incomes.
In addition to creating new jobs, increasing our use of renewable energy offers other important
economic development benefits. Local governments collect property and income taxes and other
payments from renewable energy project owners. These revenues can help support vital public
services, especially in rural communities where projects are often located. Owners of the land on
which wind projects are built also often receive lease payments ranging from $3,000 to $6,000
per megawatt of installed capacity, as well as payments for power line easements and road
rights-of-way. Or they may earn royalties based on the project’s annual revenues. Similarly,
farmers and rural landowners can generate new sources of supplemental income by producing
feedstocks for biomass power facilities.
Renewable energy projects therefore keep money circulating within the local economy, and in
most states renewable electricity production would reduce the need to spend money on importing
coal and natural gas from other places.
2.1.6.5 Stable Energy Prices:
Renewable energy is providing affordable electricity across the country right now, and can help
stabilize energy prices in the future.
The costs of renewable energy technologies have declined steadily, and are projected to drop
even more. The cost of renewable energy will decline even further as markets mature and
companies increasingly take advantage of economies of scale.
While renewable facilities require upfront investments to build, once built they operate at very
low cost and, for most technologies, the fuel is free. As a result, renewable energy prices are
relatively stable over time. UCS’s analysis of the economic benefits of a 25 percent renewable
16
electricity standard found that such a policy would lead to 4.1 percent lower natural gas prices
and 7.6 percent lower electricity prices by 2030.
In contrast, fossil fuel prices can vary dramatically and are prone to substantial price swings. For
example, there was a rapid increase in U.S. coal prices due to rising global demand before 2008,
then a rapid fall after 2008 when global demands declined. Likewise, natural gas prices have
fluctuated greatly since 2000.
Using more renewable energy can lower the prices of and demand for natural gas and coal by
increasing competition and diversifying our energy supplies. An increased reliance on renewable
energy can help protect consumers when fossil fuel prices spike.
In addition, utilities spend millions of dollars on financial instruments to hedge themselves from
these fossil fuel price uncertainties. Since hedging costs are not necessary for electricity
generated from renewable sources, long-term renewable energy investments can help utilities
save money they would otherwise spend to protect their customers from the volatility of fossil
fuel prices.
2.1.6.6 A More Reliable and Resilient Energy System
Wind and solar are less prone to large-scale failure because they are distributed and modular.
Distributed systems are spread out over a large geographical area, so a severe weather event in
one location will not cut off power to an entire region. Modular systems are composed of
numerous individual wind turbines or solar arrays. Even if some of the equipment in the system
is damaged, the rest can typically continue to operate.
The risk of disruptive events will also increase in the future as droughts, heat waves, more
intense storms, and increasingly severe wildfires become more frequent due to global warming.
Renewable energy sources are more resilient than coal, natural gas, and nuclear power plants in
the face of these sorts of extreme weather events.
For example, coal, natural gas, and nuclear power depend on large amounts of water for cooling,
and limited water availability during a severe drought or heat wave puts electricity generation at
risk. Wind and solar photovoltaic systems do not require water to generate electricity, and they
can help mitigate risks associated with water scarcity. [9]
17
2.2 Solar Energy
2.2.1 Historical Review
Solar power technology is not a recent advent; in fact, it dates back to the mid-1800s to the
industrial revolution where solar energy plants were developed to heat water that created steam
to drive machinery.
In 1839 Alexandre Edmond Becquerel discovered the photovoltaic effect which explains how
electricity can be generated from sunlight. He claimed that “shining light on an electrode
submerged in a conductive solution would create an electric current.” However, even after much
research and development subsequent to the discovery, photovoltaic power continued to be very
inefficient and solar cells were used mainly for the purposes of measuring light.
Over 100 years later, in 1941, Russell Ohl invented the solar cell, shortly after the invention of
the transistor. [9]
2.2.2 Sun and Solar Radiation
The sun is the sphere of intensely hot gaseous matter with a diameter of 1.39 x 10 9 m. The sun is
about 1.5 x 108 km away from earth so because thermal radiation travels with the speed of light
in a vacuum (300,000 km/s), after leaving the sun solar energy reaches our planet in 8 min. and
20 s. As observed from the earth, the sun disk forms an angle of 32min of degree. This is
important in many applications, especially in concentrator optics, where the sun cannot be
considered as a point source and even this small angle significant in the analysis of the optical
behavior of the collector. [10]
2.2.2.1 Earth motion around the sun
As observed from earth, the path of the sun across the sky varies through-out the ear. The shape
described by the sun’s position, considered at the same time each day for a complete year, is
called the analemma and resembles at Fig. 2.8 aligned along a north-south axis. The most
obvious version in the sun’s apparent position through the year is a north-south swing over 47 o of
angle (because of 23.5o tilt of the earth axis with respect to the sun), called declination. The
north-south swing in apparent angle is the main cause for the existence of the season on earth.
Knowledge of the sun’s path through the sky is necessary calculate the solar radiation falling on
a surface, the solar heating gain, the proper orientation of solar collectors, the placement of
collectors to avoid shading, and many more other factors.[10]
18
Fig. 2.8 Sun-earth relationships.
Source:https://www.google.com/search?q=relationship+between+earth+sun&biw=1366&bih=6
57&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIu8KAsqy1xwIVSmsUCh0
NSgQ0#tbm=isch&q=sun-earth+in+summer+and+winter&imgrc=2TLgDYbHAMW-PM%3A
2.2.3 Solar Energy Technologies
Solar Technologies are broadly characterized as either passive solar or active solar depending on
the way they capture, convert and distribute solar energy.
Active solar technologies include the use of photovoltaic panels and solar thermal collectors to
harness the energy.
Passive solar technologies include orienting a building to the sun, selecting materials with
favorable thermal mass or light dispersing properties, and designing spaces that naturally
circulate air.
Active solar technologies increase the supply of energy are considered supply side technologies,
while passive solar technologies reduce the need for alternate resources and are generally
considered demand side technologies. [11]
2.2.3.1 Architecture and Urban Planning
Solar energy must be regarded as one of the most interesting energy sources of the future. The
project solar energy in urban planning can pave the way for several practical applications.
Solar energy daily flows in, and technology is already available for converting solar energy into
both heat and electricity.
19
Nevertheless, very little is happening. The technology is as yet relatively expensive, there is a
shortage of people who have the correct “solar” knowledge, and relatively few attractive solar
energy concepts are on offer in the market.
In the Forms project “Solar energy in urban planning”, we are studying how different solar
technologies could be successfully introduced. Our starting point is the city and the urban
landscape. One important prerequisite is the ability to measure the potential for solar energy in
built-up areas and to show what possibilities and limitations we see in the present pattern of
construction.
We are also designing tools that could be of help to urban planners to plan for more solar energy
in both existing and newly constructed buildings. With the help of GIS it is possible to produce
maps which give the urban planners of today entirely different opportunities to plan for solar
energy. Another aspect that we highlight is the way solar energy can be integrated in an
architectural and aesthetic way. This provides both good examples and development needs.
One further aspect to study is the knowledge and potential of different actors to actually work
with solar energy in a constructive manner. This refers to both firms of architects and to the
architects and planners of urban areas. [12]
Fig.2.9Darmstadt University of Technology, Germany, won the 2007 Solar Decathlon in
Washington, D.C. with this passive house designed for humid and hot subtropical climate.
Source:https://en.wikipedia.org/wiki/Solar_energy#/media/File:Technische_Universit%C3%A4t
_Darmstadt_-_Solar_Decathlon_2007.jpg
20
2.2.3.2 Agriculture and Horticulture
Agriculture and horticulture seek to optimize the capture of solar energy in order to optimize the
productivity of plants. Techniques such as timed planting cycles, tailored row orientation,
staggered heights between rows and the mixing of plant varieties can improve crop yields.
Greenhouses convert solar light to heat, enabling year-round production and the growth (in
enclosed environments) of specialty crops and other plants not naturally suited to the local
climate. [13]
Fig. 2.10 Green houses like these in the Westland municipality of the Netherlands grow
vegetables, fruits and flowers.
Source:https://en.wikipedia.org/wiki/Solar_energy#/media/File:Westland_kassen.jpg
2.2.3.3 Transport
Development of a solar-powered car has been an engineering goal since the 1980s. In 1975, the
first practical solar boat was constructed in England. By 1995, passenger boats incorporating PV
panels began appearing and are now used extensively. In 1996, Kenichi Horie made the first
solar powered crossing of the Pacific Ocean, and the sun21 catamaran made the first solar
powered crossing of the Atlantic Ocean in the winter of 2006–2007. There were plans to
circumnavigate the globe in 2010. [13]
21
Fig. 2.11Winner of the 2013 World Solar Challenge in Australia.
Sources:https://en.wikipedia.org/wiki/Solar_energy#/media/File:Nuna_7.jpg
2.2.3.4 Solar Thermal
Solar thermal technologies can be used for water heating, space heating, space cooling, and
process heat generation.
2.2.3.4.1 Early commercial adaption
In 1897, Frank Shuman, a U.S. inventor, engineer and solar energy pioneer built a small
demonstration solar engine that worked by reflecting solar energy onto square boxes filled with
ether, which has a lower boiling point than water, and were fitted internally with black pipes
which in turn powered a steam engine. In 1908 Shuman formed the Sun Power Company with
the intent of building larger solar power plants. He, along with his technical advisor A.S.E.
Ackermann and British physicist Sir Charles Vernon Boys, developed an improved system using
mirrors to reflect solar energy upon collector boxes, increasing heating capacity to the extent that
water could now be used instead of ether. Shuman then constructed a full-scale steam engine
powered by low-pressure water, enabling him to patent the entire solar engine system by 1912.
[13]
2.2.3.4.2 Water heating
Solar hot water systems use sunlight to heat water. In low geographical latitudes (below
40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be
provided by solar heating systems. The most common types of solar water heaters are evacuated
tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot
water; and unglazed plastic collectors (21%) used mainly to heat swimming pools.As of 2007,
22
the total installed capacity of solar hot water systems is approximately 154 thermalgigawatt
(GWth). [13]
Fig. 2.12Solar water heaters facing the Sun to maximize gain.
Source:https://en.wikipedia.org/wiki/Solar_energy#/media/File:Twice_Cropped_Zonnecollector
en.JPG
2.2.3.4.3 Heating, cooling and ventilation
Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.
Thermal mass is any material that can be used to store heat—heat from the Sun in the case of
solar energy. Common thermal mass materials include stone, cement and water. Historically they
have been used in arid climates or warm temperate regions to keep buildings cool by absorbing
solar energy during the day and radiating stored heat to the cooler atmosphere at night. However,
they can be used in cold temperate areas to maintain warmth as well. The size and placement of
thermal mass depend on several factors such as climate, day lighting and shading conditions.
When properly incorporated, thermal mass maintains space temperatures in a comfortable range
and reduces the need for auxiliary heating and cooling equipment.
23
A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system
composed of a vertical shaft connecting the interior and exterior of a building. As the chimney
warms, the air inside is heated causing an updraft that pulls air through the building.
Deciduous trees and plants have been promoted as a means of controlling solar heating and
cooling. When planted on the southern side of a building in the northern hemisphere or the
northern side in the southern hemisphere, their leaves provide shade during the summer, while
the bare limbs allow light to pass during the winter. [13]
Fig. 2.13Solar House, used seasonal thermal energy storage for year-round heating.
Source:
https://en.wikipedia.org/wiki/Solar_energy#/media/File:Flipped_MIT_Solar_One_house.png
2.2.3.4.4 Cooking
Solar cookers use sunlight for cooking, drying and pasteurization. They can be grouped into
three broad categories: box cookers, panel cookers and reflector cookers.The simplest solar
cooker is the box cooker first built by Horace de Saussure in 1767.
A basic box cooker consists of an insulated container with a transparent lid. It can be used
effectively with partially overcast skies and will typically reach temperatures of 90–150 °C
(194–302 °F).Panel cookers use a reflective panel to direct sunlight onto an insulated container
and reach temperatures comparable to box cookers. Reflector cookers use various concentrating
geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers
reach temperatures of 315 °C (599 °F) and above but require direct light to function properly and
must be repositioned to track the Sun. [13]
24
Fig. 2.14Parabolic dish produces steam for cooking, in Auroville, India
Source: https://en.wikipedia.org/wiki/Solar_energy#/media/File:Auroville_Solar_Bowl.JPG
2.2.3.4.5 Process Heat
Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can
provide process heat for commercial and industrial applications.
Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation. The
use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar
energy. Modern uses include concentrating brine solutions used in leach mining and removing
dissolved solids from waste streams. [13]
2.2.3.4.6 Water Treatment
Solar distillation can be used to make saline or brackish water potable. Individual still designs
include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber,
multi-wick, and multiple effect. These stills can operate in passive, active, or hybrid modes.
Double-slope stills are the most economical for decentralized domestic purposes, while active
multiple effect units are more suitable for large-scale applications.
Solar energy may be used in a water stabilization pond to treat waste water without chemicals or
electricity. A further environmental advantage is that algae grow in such ponds and consume
25
carbon dioxide in photosynthesis, although algae may produce toxic chemicals that make the
water unusable. [13]
Fig. 2.15 Solar water disinfection in Indonesia.
Source: https://en.wikipedia.org/wiki/Solar_energy#/media/File:Indonesia-sodis-gross.jpg
2.2.3.5 Electricity Production
Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV),
or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and
tracking systems to focus a large area of sunlight into a small beam. PV converts light into
electric current using the photoelectric effect.
26
Fig. 2.16some of the world's largest solar power stations: Ivanpah (CSP) and Topaz (PV).
Source:https://en.wikipedia.org/wiki/Solar_energy#/media/File:IvanpahRunning.JPG
2.2.3.5.1 Photovoltaic
In the last two decades, photovoltaic (PV), also known as solar PV, has evolved from a pure
niche market of small scale applications towards becoming a mainstream electricity source. A
solar cell is a device that converts light directly into electricity using the photoelectric effect. The
first solar cell was constructed by Charles Fritts in the 1880s. In 1931 a German engineer, Dr.
Bruno Lange, developed a photo cell using silver selenide in place of copper oxide.
2.2.3.5.2 Concentrated Solar Power
Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a
large area of sunlight into a small beam. The concentrated heat is then used as a heat source for a
conventional power plant. A wide range of concentrating technologies exists; the most developed
are the parabolic trough, the concentrating linear Fresnel reflector, the Stirling dish and the solar
power tower. Various techniques are used to track the Sun and focus light. In all of these systems
a working fluid is heated by the concentrated sunlight, and is then used for power generation or
energy storage. [13]
27
2.2.3.6 Fuel Production
Solar chemical processes use solar energy to drive chemical reactions. These processes offset
energy that would otherwise come from a fossil fuel source and can also convert solar energy
into storable and transportable fuels. Solar induced chemical reactions can be divided into
thermochemical or photochemical. A variety of fuels can be produced by artificial
photosynthesis.
Hydrogen production technologies been a significant area of solar chemical research since the
1970s. Aside from electrolysis driven by photovoltaic or photochemical cells, several
thermochemical processes have also been explored. One such route uses concentrators to split
water into oxygen and hydrogen at high temperatures (2,300–2,600 °C or 4,200–4,700 °F).
Another approach uses the heat from solar concentrators to drive the steam reformation of
natural gas thereby increasing the overall hydrogen yield compared to conventional reforming
methods. [13]
2.2.3.7 Energy Storage Methods
Thermal mass systems can store solar energy in the form of heat at domestically useful
temperatures for daily or interpersonal durations. Thermal storage systems generally use readily
available materials with high specific heat capacities such as water, earth and stone. Welldesigned systems can lower peak demand, shift time-of-use to off-peak hours and reduce overall
heating and cooling requirements. [13]
Fig. 2.17Thermal energy storage. The Andasol CSP plant uses tanks of molten salt to store solar
energy.
28
Source:https://en.wikipedia.org/wiki/Solar_energy#/media/File:12-05-08_AS1.JPG
2.3 The Solar Cell
A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly
into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.[1] It is a
form of photoelectric cell, defined as a device whose electrical characteristics, such as current,
voltage, or resistance, vary when exposed to light. Solar cells are the building blocks of
photovoltaic modules, otherwise known as solar panels.
Solar cells are described as being photovoltaic irrespective of whether the source is sunlight or
an artificial light. They are used as a photo detector (for example infrared detectors), detecting
light or other electromagnetic radiation near the visible range, or measuring light intensity.
The operation of a photovoltaic (PV) cell requires 3 basic attributes:

The absorption of light, generating either electron-hole pairs or excitons.

The separation of charge carriers of opposite types.

The separate extraction of those carriers to an external circuit.
In contrast, a solar thermal collector supplies heat by absorbing sunlight, for the purpose of either
direct heating or indirect electrical power generation from heat. A "photoelectrolytic cell"
(photoelectrochemical cell), on the other hand, refers either to a type of photovoltaic cell (like
that developed by Edmond Becquerel and modern dye-sensitized solar cells), or to a device that
splits water directly into hydrogen and oxygen using only solar illumination.[14]
Photovoltaic (PV) is the name of a method of converting solar energy into direct
currentelectricity using semiconducting materials that exhibit the photovoltaic effect, a
phenomenon commonly studied in physics, photochemistry and electrochemistry. A photovoltaic
system employs solar panels composed of a number of solar cells to supply usable solar power.
The process is both physical and chemical in nature, as the first step involves the photoelectric
effect from which a second electrochemical process take place involving crystallized atoms
being ionized in a series, generating an electric current. Power generation from solar PV has long
been seen as a clean sustainable.[15]
29
Fig. 2.18Solar Cell produce electricity directly from sunlight.
Source:https://en.wikipedia.org/wiki/Solar_cell#/media/File:Solar_cell.png
2.3.1 The Cell Basic Construction
2.3.1.1 How does it Work?
Solar (or photovoltaic) cells convert the sun’s energy into electricity. Whether they’re adorning
your calculator or orbiting our planet on satellites, they rely on the photoelectric effect: the
ability of matter to emit electrons when a light is shone on it.
Silicon is what is known as a semi-conductor, meaning that it shares some of the properties of
metals and some of those of an electrical insulator, making it a key ingredient in solar cells. Let’s
take a closer look at what happens when the sun shines onto a solar cell.
Sunlight is composed of miniscule particles called photons, which radiate from the sun. As these
hit the silicon atoms of the solar cell, they transfer their energy to loose electrons, knocking them
clean off the atoms. The photons could be compared to the white ball in a game of pool, which
passes on its energy to the colored balls it strikes.
Freeing up electrons is however only half the work of a solar cell: it then needs to herd these
stray electrons into an electric current. This involves creating an electrical imbalance within the
cell, which acts a bit like a slope down which the electrons will flow in the same direction.
Creating this imbalance is made possible by the internal organization of silicon. Silicon atoms
are arranged together in a tightly bound structure. By squeezing small quantities of other
elements into this structure, two different types of silicon are created: n-type, which has spare
electrons, and p-type, which is missing electrons, leaving ‘holes’ in their place.
30
When these two materials are placed side by side inside a solar cell, the n-type silicon’s spare
electrons jump over to fill the gaps in the p-type silicon. This means that the n-type silicon
becomes positively charged, and the p-type silicon is negatively charged, creating an electric
field across the cell. Because silicon is a semi-conductor, it can act like an insulator, maintaining
this imbalance.
As the photons smash the electrons off the silicon atoms, this field drives them along in an
orderly manner, providing the electric current to power calculators, satellites and everything in
between.
Fig. 2.19A working scheme of how solar works.
Sources:
https://www.google.com/search?q=relationship+between+earth+sun&biw=1366&bih=657&sour
ce=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIu8KAsqy1xwIVSmsUCh0NSgQ0#
tbm=isch&q=solar+energy+images&imgrc=zTMvtTpQPoXnUM%3A
31
2.3.1.2 Photovoltaic Cells Materials
Solar cells are typically named after the semiconducting material they are made of. These
materials must have certain characteristics in order to absorb sunlight. Some cells are designed to
handle sunlight that reaches the Earth's surface, while others are optimized for use in space. Solar
cells can be made of only one single layer of light-absorbing material (single-junction) or use
multiple physical configurations (multi-junctions) to take advantage of various absorption and
charge separation mechanisms.
Solar cells can be classified into first, second and third generation cells. The first generation
cells—also called conventional, traditional or wafer-based cells—are made of crystalline silicon,
the commercially predominant PV technology, that includes materials such as polysilicon and
monocrystalline silicon. Second generation cells are thin film solar cells, that include amorphous
silicon, CdTe and CIGS cells and are commercially significant in utility-scale photovoltaic
power stations, building integrated photovoltaic or in small stand-alone power system. The third
generation of solar cells includes a number of thin-film technologies often described as emerging
photovoltaic—most of them have not yet been commercially applied and are still in the research
or development phase. Many use organic materials, often organometallic compounds as well as
inorganic substances. Despite the fact that their efficiencies had been low and the stability of the
absorber material was often too short for commercial applications, there is a lot of research
invested into these technologies as they promise to achieve the goal of producing low-cost, highefficiency solar cells.
2.3.1.2.1 Crystalline Silicon
By far, the most prevalent bulk material for solar cells is crystalline silicon (c-Si), also known as
"solar grade silicon". Bulk silicon is separated into multiple categories according to crystallinity
and crystal size in the resulting ingot, ribbon or wafer. These cells are entirely based around the
concept of a p-n junction. Solar cells made of c-Si are made from wafers between 160 to
240 micrometers thick.
Monocrystalline silicon
Monocrystalline silicon (mono-Si) solar cells are more efficient and more expensive than
most other types of cells. The corners of the cells look clipped, like an octagon, because
the wafer material is cut from cylindrical ingots, that are typically grown by the
Czochralski process. Solar panels using mono-Si cells display a distinctive pattern of
small white diamonds.
Polycrystalline silicon
Polycrystalline silicon, or multicrystalline silicon (multi-Si) cells are made from cast
square ingots—large blocks of molten silicon carefully cooled and solidified. They
consist of small crystals giving the material its typical metal flake effect. Polysilicon cells
32
are the most common type used in photovoltaic and are less expensive, yet less efficient
than those made from monocrystalline silicon.
Ribbon silicon
Ribbon silicon is a type of polycrystalline silicon—it is formed by drawing flat thin films
from molten silicon and results in a polycrystalline structure. These cells have lower
efficiencies and costs than multi-Si due to a great reduction in silicon waste, as this
approach does not require sawing from ingots.
Mono-like-multi silicon (MLM)
This form was developed in the 2000s and introduced commercially around 2009. Also
called cast-mono, this design uses polycrystalline casting chambers with small "seeds" of
mono material. The result is a bulk mono-like material that is polycrystalline around the
outsides. When sliced for processing, the inner sections are high-efficiency mono-like
cells (but square instead of "clipped"), while the outer edges are sold as conventional
poly. This production method results in mono-like cells at poly-like prices.
2.3.1.2.2 Thin film
Thin-film technologies reduce the amount of active material in a cell. Most designs sandwich
active material between two panes of glass. Since silicon solar panels only use one pane of glass,
thin film panels are approximately twice as heavy as crystalline silicon panels, although they
have a smaller ecological impact (determined from life cycle analysis).[35] The majority of film
panels have 2-3 percentage points lower conversion efficiencies than crystalline
silicon.[36]Cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous
silicon (a-Si) are three thin-film technologies often used for outdoor applications. As of
December 2013, CdTe cost per installed watt was $0.59 as reported by First Solar. CIGS
technology laboratory demonstrations reached 20.4% conversion efficiency as of December
2013. The lab efficiency of GaAs thin film technology topped 28%. The quantum efficiency of
thin film solar cells is also lower due to reduced number of collected charge carriers per incident
photon. Most recently, CZTS solar cell emerge as the less-toxic thin film solar cell technology,
which achieved ~12% efficiency. Thin film solar cells are increasing due to it being silent,
renewable and solar energy being the most abundant energy source on Earth.
Cadmium telluride
Cadmium telluride is the only thin film material so far to rival crystalline silicon in
cost/watt. However cadmium is highly toxic and tellurium (anion: "telluride") supplies
are limited. The cadmium present in the cells would be toxic if released. However,
release is impossible during normal operation of the cells and is unlikely during fires in
residential roofs.A square meter of CdTe contains approximately the same amount of Cd
as a single C cell nickel-cadmium battery, in a more stable and less soluble form.
33
Copper indium gallium selenide
Copper indium gallium selenide (CIGS) is a direct band gap material. It has the highest
efficiency (~20%) among all commercially significant thin film materials (see CIGS solar
cell). Traditional methods of fabrication involve vacuum processes including coevaporation and sputtering. Recent developments at IBM and Nano solar attempt to lower
the cost by using non-vacuum solution processes.
Silicon thin film
Silicon thin-film cells are mainly deposited by chemical vapor deposition (typically
plasma-enhanced, PE-CVD) from silane gas and hydrogen gas. Depending on the
deposition parameters, this can yield amorphous silicon (a-Si or a-Si:H), protocrystalline
silicon or nanocrystalline silicon (nc-Si or nc-Si:H), also called microcrystalline silicon.
Amorphous silicon is the most well-developed thin film technology to-date. An
amorphous silicon (a-Si) solar cell is made of non-crystalline or microcrystalline silicon.
Amorphous silicon has a higher bandgap (1.7 eV) than crystalline silicon (c-Si) (1.1 eV),
which means it absorbs the visible part of the solar spectrum more strongly than the
higher power density infrared portion of the spectrum. The production of a-Si thin film
solar cells uses glass as a substrate and deposits a very thin layer of silicon by plasmaenhanced chemical vapor deposition (PECVD).
Protocrystalline silicon with a low volume fraction of nanocrystalline silicon is optimal
for high open circuit voltage. Nc-Si has about the same bandgap as c-Si and nc-Si and aSi can advantageously be combined in thin layers, creating a layered cell called a tandem
cell. The top cell in a-Si absorbs the visible light and leaves the infrared part of the
spectrum for the bottom cell in nc-Si.
Gallium arsenide thin film
The semiconductor material Gallium arsenide (GaAs) is also used for single-crystalline
thin film solar cells. Although GaAs cells are very expensive, they hold the world's
record in efficiency for a single-junction solar cell at 28.8%. GaAs is more commonly
used in multijunction photovoltaic cells for concentrated photovoltaic (CPV, HCPV) and
for solar panels on spacecrafts, as the industry favors efficiency over cost for space-based
solar power.
2.3.1.2.3 Multijunction cells
Multi-junction cells consist of multiple thin films, each essentially a solar cell grown on top of
each other, typically using metal organicvapor phase epitaxy. Each layers has a different band
gap energy to allow it to absorb electromagnetic radiation over a different portion of the
spectrum. Multi-junction cells were originally developed for special applications such as
satellites and space exploration, but are now used increasingly in terrestrial concentrator
photovoltaic (CPV), an emerging technology that uses lenses and curved mirrors to concentrate
34
sunlight onto small but highly efficient multi-junction solar cells. By concentrating sunlight up to
a thousand times, highconcentratephotovoltaic (HCPV) has the potential to outcompete
conventional solar PV in the future.
Tandem solar cells based on monolithic, series connected, gallium indium phosphide (GaInP),
gallium arsenide (GaAs), and germanium (Ge) p–n junctions, are increasing sales, despite cost
pressures.[45] Between December 2006 and December 2007, the cost of 4N gallium metal rose
from about $350 per kg to $680 per kg. Additionally, germanium metal prices have risen
substantially to $1000–1200 per kg this year. Those materials include gallium (4N, 6N and 7N
Ga), arsenic (4N, 6N and 7N) and germanium, pyrolitic boron nitride (pBN) crucibles for
growing crystals, and boron oxide, these products are critical to the entire substrate
manufacturing industry.[17]
2.3.2 Current Development
Researchers have longed looked for ways to improve the efficiency and cost-effectiveness of
solar cells - the life blood of solar PV systems. A solar PV array is comprised of hundreds,
sometimes thousands of solar cells, that individually convert radiant sun light into electrical
currents. The average solar cell is approximately 15% efficient, which means nearly 85% of the
sunlight that hits them does not get converted into electricity. As such, scientists have constantly
been experimenting with new technologies to boost this light capture and conversion.
Light-Sensitive Nanoparticles. Recently, a group of scientists at the University of Toronto
unveiled a new type of light-sensitive nanoparticle called colloidal quantum dots, that many
believe will offer a less expensive and more flexible material for solar cells. Specifically, the
new materials use n-type and p-type semiconductors - but ones that can actually function
outdoors. This is a unique discovery since previous designs weren't capable of functioning
outdoors and therefore not practical applications for the solar market. University of Toronto
researchers discovered that n-type materials bind to oxygen - the new colloidal quantum dots
don't bind to air and therefore can maintain their stability outside. This helps increase radiant
light absorption. Panels using this new technology were found to be up to eight percent more
efficient at converting sunlight.[18]
2.3.3 Advances in Energy Storage
Another major focus of scientists is to find new ways to store energy produced by solar PV
systems. Currently, electricity is largely a "use it or lose it" type resource whereby once it's
generated by a solar PV system (or any type of fuel source) the electricity goes onto the grid and
must be used immediately or be lost. Since the sunlight does not shine twenty four hours a day,
this means that most solar PV systems are only meeting electrical demands for a portion of the
day as a result, a lot of electricity is lost, if it's not used. There are a number of batteries on the
market that can store this energy, but even the most high-tech ones are fairly inefficient; they're
also expensive and have a pretty short shelf life, making them not the most attractive options for
35
utility companies and consumers. That is why scientists are exploring different ways to store this
electricity so that it can be used on demand. [18]
2.4 The Solar Battery
A key problem with solar power is that a significant amount of energy is lost when the electrons
move from the solar panel to the battery that stores the energy. A group of researchers from The
Ohio State University (OSU) has fortunately come up with a first of its kind solar battery that
can both capture and store the sun's energy.
Reporting their innovation in "Integrating a redox-coupled dye-sensitized photoelectrode into a
lithium-oxygen battery for photoassisted charging", which was published in the journal Nature
Communications on Oct. 3, OSU chemistry and biochemistry professor Yiying Wu and
colleagues said that they have successfully fused solar cell and a battery into one hybrid device
using mesh solar panels and a process that facilitates the transfer of electrons between the solar
panel and the battery.
The team has come up with a solution for the loss of up to 20 percent of energy when electrons
are transferred from the solar cells to a separate battery unit by fusing the battery right into the
panel. The technology allows sunlight to be converted into electrons inside the battery saving
almost 100 percent of the electrons and solving a problem with solar energy efficiency wherein
only 80 percent of the electrons from the solar cells get into the battery for storage.
The new hybrid device runs on light and oxygen and traps electricity using a simple chemical
reaction. Electrons are produced when light from the sun hits the mesh solar panel. The electrons
inside the battery then get involved when lithium peroxide decomposes into lithium ions and
oxygen. While the oxygen is released into the air, the lithium ions get stored in the battery as
lithium metal.
36
Fig. 2.20 the charge controller is the heart of any solar power system like this. It takes the power
from the solar panels and charges the battery in a precisely controlled way.
Source:https://www.google.com/search?q=the+solar+cell+Battery&biw=1366&bih=657&tbm=i
sch&tbo=u&source=univ&sa=X&ved=0CC0QsARqFQoTCL7M2NShtccCFciXGgodoxEKVg#i
mgrc=nxcIpfYulOH0fM%3A
2.5 The Solar Inverter
A solar inverter converts the electricity from your solar panels (DC, or direct current) into power
that can be used by the plugs in your house for your TV, computer, and other wired products
(AC, or alternating current). Panels can’t create AC power by themselves; they need the helping
hand of a solar inverter.
37
Fig. 2.21SMA Solar Inverter.
Source:http://pureenergies.com/us/how-solar-works/solar-inverters/
2.5 The Solar System Wiring
This is an example of a typical 2 Kilowatts system.
Fig. 2.22a typical 2 Kilowatts solar system wiring diagram.
38
Source:
https://www.google.com/search?q=relationship+between+earth+sun&biw=1366&bih=657&sour
ce=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIu8KAsqy1xwIVSmsUCh0NSgQ0#
tbm=isch&q=solar+system+wiring&imgrc=BHCDHrVYFS0mGM%3A
2.6 Solar Energy in Sudan
Sudan is blessed with abundant sun shine, high quality solar radiation, moderate wind; huge
hydro and biomass energy resources.
Resource assessment studies suggest that, renewable energy must be encouraged, promoted by
governments, policies and generous investments in research development and demonstration of
new technologies, specially, in remote rural area.
2.6.1 Solar Radiation in Sudan
Sudan has been considered as one of the best countries for exploiting solar energy. The sun shine
duration is ranging from 7 to 11 hours per day with high level of solar radiation regime at
average of 20 to 25 MJm- 2 days -1 on a horizontal surface. The annual daily mean global
radiation ranges from 3.05 to 7.62 Kw.hr.m2day-1.
However, Sudan has an average of 7-9 GJm a year and equivalent to 436-639 W/m2 year.
2.6.1 Latest Solar Photovoltaic Research Work in Sudan
A recent Lamheyer International study funded by the Ministry of Electricity and Dams in Sudan
discussed the potential for solar photovoltaic in supplying electricity in Sudan. The study
reviewed their potential sitesto install 10 MW solar power generation plant, below are the
suggested locations
(1) Khartoum, Garri,
(2) Western Sudan ( Nyala, AlGeniena, AlFashir)
The study also made a determination on the key layout parameters to analyze potential of solar
photovoltaic electricity generation for Sudan energy system. [21]
39
Chapter Three
Material and
Methods
40
3. Material and Methods
3.1 Introduction
This chapter describes the economic study used to compare between two methods of generating
electricity. It compares between conventional power generation sources currently used to
generate power in Sudan and PV (photovoltaic) systems for generating electricity at household.
This can be performed first by calculating the cost electricity consumption for three different
capacity houses (Low, Medium, and High) randomly chosen in Khartoum state, using data from
Ministry of Electricity and Dams, Electricity Distribution Company. Secondly the Design
process for three similar capacity PV (Photovoltaic) houses can be easily done by using data and
equations given by Renewable Energy unit in Ministry of Electricity and Dams. The last step is
to compare between the costs of two energy generation sources considered.
3.2 Electricity Consumption in Houses
Electricity consumption in houses depends on type of electrical devices used and their quantity.
Electrical devices commonly used and considered in calculation are like Refrigerators, Light,
TVs, and Fans … etc. The electricity consumption measured for each house according to
consumption of each device and their numbers will determine the total consumption of the
house, after that the power consumption calculation of similar PV (Photovoltaic) powered house
can be obtained by using the electricity consumption calculated, Global Radiation Factor (G),
and Loss Factor (LF), and also power meters in the houses.
3.3 Global Radiation
For better understanding of fluctuation of solar conditions GHI (Global Horizontal Irradiation) in
Sudan, and for selection most suitable sites for utility scale, solar power plants monthly maps
have been prepared. (See Appendix A)
GHI (Global Horizontal Irradiation) map is very important document taken from Ministry of
Electricity and Dams to determine the values of climate data during the entire year which help in
finding the value of Global Radiation (G) by applying the following equation:
G = ∑ (Climate data for each month in the year) [KW/m2/day] ………………………….. (3.1)
12
40
3.4 PV (Photovoltaic) Systems Power Consumption Equation
The main formula used to calculate the power consumed by a solar house is given as below:
Ppv = E / (LF * G)KWp…………………………….. (3.2)
Where:
Ppv = Total Cell Power which is equivalent to the daily consumption for one house,
E = Energy consumption [Wh/day],
LF = Loss PV-Array Factor, 80%
G = Global Radiation [KW/m2/day].
3.5 Selection of Battery
To select a battery fora PV (Photovoltaic) system it requires to know the value of its current,
which can be simply obtained from equation below:
AB =
E
Ah …………………………….. (3.3)
η * D.O.D * V
Where:
AB = Battery Current [Ah],
E = Total Electricity consumption [Wh/day],
η = Efficiency of Battery [%],
D.O.D = Deep of discharge [%],
V = Volts [V].
41
3.6 Inverter Capacity
Choosing a suitable Inverter depends on determining its total capacity. The total capacity of an
inverter is calculated from the forthcoming equations.
Sizing Factor:
CINV= PPV, DC / PINV, AC = (65 -95) % …………………….. (3.4)
Where:
CINV = Inverter Sizing Factor [%]
Inverter Power:
PINV= (1.1 – 1.66) * PPV
………………………………… (3.5)
PINV = Inverter Power [KW]
Then:
Min PINV = 1.1 * PPV
[KW]
Max PINV = 1.66 * PPV
[KW]
For optimum selection we choose the higher value PINV, Max to ensure safe design for PV
(Photovoltaic) System.
42
Chapter Four
Result and
Discussion
43
4. Result and Discussion
4.1 Results
An economical study was performed to investigate the feasibility of using PV (Photovoltaic)
system in Sudanese houses. The study was applied to three different power consumption levels
low, medium, and high according to its electricity consumption per day using data given by
Ministry of Electricity and Dams.
4.1.1 Global Radiation Calculations
From GHI (Global Horizontal Irradiation) maps for Republic of Sudan in Appendix (A), the
value of global radiation (G) can be obtained for each month in the year, and they represented in
the following table below:
Table 4.1Global Radiation Throughout the year in Sudan
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
G
5.77
6.27
7.27
7.27
7.27
6.77
6.27
6.27
6.27
6.27
5.77
5.77
6.4
G = ∑ (Climate data for each month in the year)
12
G = 5.77 + 6.27 + 7.27 + 7.27 + 7.27 + 6.77 + 6.27 + 6.27 + 6.27 + 6.27 + 5.77 + 5.77
12
G = 6.4 Kw/m2/day.
43
4.1.2 Low Level Calculations
4.2.1.1 Low Level Electricity Consumption Calculations
Table 4.2 Electricity Consumption for low level
No.
Description
Type Quantity
Power Consumed
Operation Time
Total Energy
[KW]
[h/day]
[KWh/day]
1
Refrigerator
AC
1
0.112
20
2.24
2
A/C Split Type
AC
1
3
8
24
3
Light
AC
15
0.04
12
7.2
4
Evaporative Cooler
AC
1
0.25
10
2.5
5
TV
AC
1
0.04
15
0.6
6
Digital
AC
1
0.04
15
0.6
7
Fan
AC
3
0.15
20
9
#
Total
46.14
Source: Ministry of Electricity and Dams.
4.1.2.2 PV (Photovoltaic) System Design for Low Level
PV (Photovoltaic) Systems Power Consumption
Ppv = E / (LF * G) KWp
Ppv = 46.14 / (0.8 * 6.4) = 9 KWp
Number of Cells for PV (Photovoltaic) Systems
Assume that solar cell capacity is 100 Watt. Then
No. of Cells = 9 KW * 1000 / 100 = 90 Cells
44
Selection of Battery for PV (Photovoltaic) Systems
AB =
E
Ah
η * D.O.D * V
AB =46.14 * 1000
= 6462.6 Ah
0.85 * 0.7 * 12
Inverter Capacity for PV (Photovoltaic) Systems
Min PINV = 1.1 * PPV [KW]
Min PINV = 1.1 * 9 = 9.9 KW
Max PINV = 1.66 * PPV [KW]
Max PINV = 1.66 * 9 = 14.94 KW
Take the maximum value to ensure better selection, so
PINV ~ 15 KW
45
4.1.3 Medium Level Calculations
4.1.3.1 Medium Level Electricity Consumption Calculations
Table 4.3 Electricity Consumption for medium level
No.
Description
Type
Quantity
Power Consumed
Operation Time
Total Energy
[KW]
[h/day]
[KWh/day]
1
Water Pump
AC
1
0.25
6
1.5
2
Lamps
AC
6
0.04
12
2.88
3
Digital
AC
1
0.04
15
0.6
4
A/C Split Type
AC
3
3
10
90
5
Refrigerator
AC
2
0.112
18
4.032
6
Fan
AC
5
0.15
20
15
7
Iron
AC
1
1
1
1
8
Evaporator Cooler
AC
1
0.25
12
3
9
TV
AC
1
0.04
15
0.6
#
Total
118.612
Source: Ministry of Electricity and Dams.
46
4.1.3.2 PV (Photovoltaic) System Design for Medium Level
PV (Photovoltaic) Systems Power Consumption
Ppv = E / (LF * G) KWp
Ppv = 118.612 / (0.8 * 6.4) = 23.2 KWp
Number of Cells for PV (Photovoltaic) Systems
Assume that solar cell capacity is 100 Watt. Then
No. of Cells = 23.2 KW * 1000 / 100 = 232 Cells
Selection of Battery for PV (Photovoltaic) Systems
AB =
E
Ah
η * D.O.D * V
AB =
118.612 * 1000
= 16612.3 Ah
0.85 * 0.7 * 12
Inverter Capacity for PV (Photovoltaic) Systems
Min PINV = 1.1 * PPV [KW]
Min PINV = 1.1 * 23.2 = 25.52 KW
Max PINV = 1.66 * PPV [KW]
Max PINV = 1.66 * 23.2 = 38.512 KW
Take the maximum value to ensure better selection, so
PINV ~ 39 KW
47
4.1.4HighLevel Calculations
4.1.4.1High Level Electricity Consumption Calculations
Table 4.4Electricity Consumption for high level
No.
Description
Type Quantity
Power Consumed
Operation Time
Total Energy
[KW]
[h/day]
[KWh/day]
1
Lamps
AC
40
0.04
12
19.6
2
Digital
AC
1
0.04
15
0.6
3
A/C Split Type
AC
3
3
10
90
4
Refrigerator
AC
1
0.112
18
2.016
5
Fan
AC
8
0.15
20
24
6
Iron
AC
1
1
2
2
7
TV
AC
1
0.04
15
0.6
8
Water Cooler
AC
1
0.112
12
1.344
9
Washing Machine
AC
1
0.375
1
0.375
10
Deep Freezer
AC
1
0.75
12
9
11
Computer
AC
1
0.04
6
0.24
12
Water Boiler
AC
1
2
2
4
13
Mixer
AC
1
0.12
1
0.12
#
Total
153.895
Sources: Ministry of Electricity and Dams.
48
4.1.4.2 PV (Photovoltaic) System Design for High Level
PV (Photovoltaic) Systems Power Consumption
Ppv = E / (LF * G) KWp
Ppv = 153.895 / (0.8 * 6.4) = 30.06 KWp
Number of Cells for PV (Photovoltaic) Systems
Assume that solar cell capacity is 100 Watt. Then
No. of Cells = 30.06 KW * 1000 / 100 = 300.6 ~ 301 Cells
Selection of Battery for PV (Photovoltaic) Systems
AB =
E
Ah
η * D.O.D * V
AB =
153.895 * 1000
= 21553 Ah
0.85 * 0.7 * 12
Inverter Capacity for PV (Photovoltaic) Systems
Min PINV = 1.1 * PPV [KW]
Min PINV = 1.1 * 30.06 = 33.066 KW
Max PINV = 1.66 * PPV [KW]
Max PINV = 1.66 * 30.06 = 49.9 KW
Take the maximum value to ensure better selection, so
PINV ~ 50 KW
49
Summary:
Table 4.5 PV Systems Design Summary
No.
Level Size
Total Energy
Consumption
PV SystemPower
Ppv [KWP]
No. of
Cells
[KW/h/day]
Battery
Current
InverterCapa
city
AB [Ah]
Pinv [KW]
1
Low
46.14
9
90
6462.6
15
2
Medium
118.612
23.2
232
16612.3
39
3
High
153.895
30.06
301
21553
50
4.1.5PV (Photovoltaic) Systems Estimated Cost
4.1.5.1 Price List
Table 4.6 Prices for PV System components
No.
Description
Price ($)
1
Solar Cell [1 W]
0.6
2
Cell Battery [1 Ah]
1.2
3
Cell Inverter [1 W]
0.3
4
Wiring
1 % Total Price
4.1.5.2 Initial Cost Calculations for Solar Houses
Table 4.7Power Requirements for PV (Photovoltaic) System Components
No.
Device
Low
Medium
High
1
Solar Cell [W]
9000
23200
30060
2
Battery [Ah]
6462.6
16612.3
21553
3
Inverter [W]
15000
39000
50000
50
For Low Level:
Total Price = 9000 * 0.6 + 15000 * 0.3 + 6462.6 * 1.2 = 17655.12 $
Wiring Cost = 17655.12 * 0.01 = 176.55 $
Initial Cost = 17655.12 + 176.55 = 17831.7 $
For Medium Level:
Total Price = 23200 * 0.6 + 39000 * 0.3 + 16612.3 * 1.2 = 45554.76 $
Wiring Cost = 45554.76 * 0.01 = 455.55 $
Initial Cost = 45554.76 + 455.55 = 46010.3 $
For High Level:
Total Price = 30060 * 0.6 + 50000 * 0.3 + 21553 * 1.2 = 58899.6 $
Wiring Cost = 58899.6 * 0.01 = 589 $
Initial Cost = 58899.6 + 589 = 59488.6 $
4.1.5.3 Full Operational Life time Cost
The operational life time for any solar system is approximately about 24 years, now full
operational life time cost should be calculated to know the actual cost of the solar system
throughout its entire life time.
During PV (Photovoltaic) system life time it requires 4 batteries to run the system, so the full life
time cost will be as follows:
For Low Level:
Full Operational Life time Cost = 9000 * 0.6 + 15000 * 0.3 + 6462.6 * 1.2 * 4 + 176.55
= 41097 $
Total Cost per month
= 41097 / (24 * 12) = 142.7 $
51
For Medium Level:
Full Operational Life time Cost= 23200 * 0.6 + 39000 * 0.3 + 16612.3 * 1.2 * 4 + 455.55
= 105815 $
Total Cost per month
= 105815 / (24 * 12) = 367.4 $
For High Level:
Full Operational Life time Cost = 30060* 0.6 + 50000 * 0.3 + 21553 * 1.2 * 4 + 589
= 137080 $
Total Cost per month
= 137080 / (24 * 12) = 476 $
Summary:
Table 4.8 PV Systems Cost Estimation
No.
Costs
Low
Medium
High
1
Total Price ($)
17655.12
45554.76
58899.6
2
Wiring Cost ($)
176.55
455.55
589
3
Initial Cost ($)
17831.7
46010.3
59488.6
4
Full Operational Life time Cost ($)
41097
105815
137080
5
Total Cost per month ($)
142.7
367.4
476
6
Total Cost per month (SDG)
1370
3527
4570
52
4.1.6 Electricity Cost Estimation
Monthly Electricity Cost for Low Level:
Total energy consumed per day * 1 KW generation cost* 30 = 46.14 * 0.9 * 30 = 1245.78 SDG
Monthly Electricity Cost for Medium House:
Total energy consumed per day * 1 KW generation cost* 30 = 118.612 * 0.9 * 30 = 3202.5 SDG
Monthly Electricity Cost for High Level:
Total energy consumed per day * 1 KW generation cost* 30 = 153.895 * 0.9 * 30 = 4155.2 SDG
4.2 Discussion
Table 4.9 Comparison between electricity cost and PV system total cost
No.
Level Size
Monthly Grid
Electricity
Consumption (KW)
Monthly Grid
Electricity Cost
Total PV system Cost
per month
(SDG)
(SDG)
1
Small
1384.2
1245.78
1370
2
Medium
3558.3
3202.5
3527
3
Large
4616.9
4155.2
4570
From table4.8 the total initial cost for installing a PV System is slightly expensive, but its
running cost is seemed to be considerable, so that the full operational cost during its whole life
time is acceptable.
Table 4.9depicts that total PV system cost per month is not much higher than the monthly cost of
electricity generation; in addition PV systems have a more considerable running cost than
conventional electricity generation sources through its life time.
53
Chapter Five
Conclusion and
Recommendations
54
5. Conclusion and Recommendations
5.1 Conclusion
As shown in the study result, the total PV system cost per month is not much higher than the
monthly cost of electricity generation, in addition PV systems have a more considerable running
cost than conventional electricity generation sources through its life time.
Results from this study showed that it’s feasible to use a PV System as a source of electricity in
Sudanese houses because of its running cost is seemed to be considerable although its initial cost
is slightly expensive, so that the full operational cost during its whole life time is acceptable.
Finally, this study conclude that economically it’s better to use PV (Photovoltaic) system in
generating electricity for domestic application in Sudan.
5.2 Recommendations
Sudan is blessed with abundant sunshine and high quality solar radiation, if properly developed,
will provide a cheap and sustainable alternative to conventional energy sources. Results from this
project show that solar energy must be encouraged, promoted by government’s policies and
generous incentives in research, development and demonstration of new technologies, specially,
in remote rural areas.
Regarding this project, the following is recommended:
(1) In order to keep the cost down, local manufacturing is highly encouraged whenever
possible to build local capacity and improve the economy.
(2) This is an economy study so it needs a tremendous work to bring it to reality, and this can
be obtained by contribution and efforts of many team works.
(3) Participation of the Government, donor organizations, producers, and end-users is highly
required to realize more renewable deployments in Sudan.
54
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