To Develop the Technical Feasibility of Very Large Scale Photovoltaic Systems

for Desert Areas of Pakistan

by

ASIF RASOOL

Thesis submitted to the faculty of PIEAS in partial fulfillment of requirements for the MS Nuclear Power Engineering

Karachi Institute of Power Engineering Karachi Nuclear Power Complex

Karachi November, 2010

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Karachi Institute of Power Engineering Karachi Nuclear Power Complex

Karachi

Declaration of Originality I hereby declare that the work contained in this thesis and the intellectual content of

this thesis are the product of my own work. This thesis has not been previously

published in any form nor does it contain any verbatim of the published resources

which could be treated as infringement of the international copyright law.

I also declare that I do understand the terms ‘copyright’ and ‘plagiarism,’ and

that in case of any copyright violation or plagiarism found in this work, I will be held

fully responsible of the consequences of any such violation.

Signature:

Name:

Date:

Place:

iv

Certificate of Approval

This is to certify that the work contained in this thesis entitled

“To Develop the Technical Feasibility of Very large Scale

Photovoltaic Systems for Desert Areas of Pakistan”

was carried out by

ASIF RASOOL

under our supervision and that in our opinion, it is fully adequate, in scope and

quality, for the degree of MS Nuclear Power Engineering

Approved: Signature:________________________

Supervisor: Dr. ANWAR UL HASSON, SYED

Signature:________________________

Co-Supervisor: Mr. MUHAMMAD SHAHZAD MASOOD

Signature:________________________

Co-Supervisor: Ms. NAILA ZAREEN

Verified: Signature:________________________

Director, Karachi Institute of Power Engineering

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Dedication Dedicated to mother who is the most beloved human being for me in this

world

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Acknowledgement First of all Thanks to Almighty Allah who gave me courage to put my efforts

for this project work.

Then I would like to Thanks Mr. Thomas Huld, member of Joint Research

Centre for providing me assistance in this project. A special Thanks to my

advisors Dr. Anwar ul Hasson and Muhammad Shahzad Masood who guided

me throughout this project work.

ASIF RASOOL

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Contents ACKNOWLEDGEMENT ...................................................................................................................... VI 

CONTENTS ........................................................................................................................................... VII 

LIST OF FIGURES .................................................................................................................................. X 

LIST OF TABLES ................................................................................................................................... XI 

ABSTRACT ........................................................................................................................................... XII 

NOMENCLATURE ............................................................................................................................ XIII 

CHAPTER 1  INTRODUCTION ........................................................................................................ 1 

1.1  ENERGY AND ITS NEEDS ................................................................................................................ 1 

1.2  VERY LARGE SCALE PHOTOVOLTAIC SYSTEMS ............................................................................ 1 

1.3  DESERT POTENTIAL ....................................................................................................................... 2 

1.4  KINDS OF DESERTS ........................................................................................................................ 3 

1.5  DESERTS IN PAKISTAN ................................................................................................................... 3 

1.5.1  Thar Desert .......................................................................................................................... 3 

1.5.2  Cholistan Desert .................................................................................................................. 4 

1.5.3  Kharan Desert ...................................................................................................................... 4 

1.6  ENVIRONMENTAL ASPECTS ........................................................................................................... 4 

1.7  VLS-PV AND OTHER RENEWABLE RESOURCES ............................................................................ 5 

1.8  VLS-PV IN FUTURE ....................................................................................................................... 5 

CHAPTER 2  SITE SELECTION ...................................................................................................... 6 

2.1  PARAMETERS FOR SITE SELECTION ............................................................................................... 6 

2.2  PROBABLE SITES IN PAKISTAN ...................................................................................................... 6 

2.3  NASA DATABASE ......................................................................................................................... 7 

2.4  SOLAR DATA FOR LISTED SITES .................................................................................................... 8 

2.4.1 Insolation on a Horizontal Surface ........................................................................................... 8 

2.4.2 Clear Sky Insolation ................................................................................................................. 9 

2.4.3 Midday Insoltaion on a Horizontal Surface ........................................................................... 10 

2.4.4 Direct Normal Radiation ........................................................................................................ 11 

2.4.5 Surface Albedo ....................................................................................................................... 12 

2.5.6 Insolation Clearness Index ..................................................................................................... 13 

2.4.7 Daylight hours ........................................................................................................................ 14 

2.4.8 Declination .............................................................................................................................. 15 

2.5  METEOROLOGICAL DATA FOR LISTED SITES .............................................................................. 16 

2.5.1 Relative Humidity ................................................................................................................... 16 

2.5.2 Atmospheric Pressure ............................................................................................................. 17 

2.5.3 Precipitation ............................................................................................................................ 18 

2.5.4 Air Temperature at 10 m above the Surface of Earth ............................................................ 19 

2.5.5 Earth Skin Temperature .......................................................................................................... 20 

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2.6  PARAMETERS FOR TILTED SOLAR PANELS .................................................................................. 21 

2.6.1 Optimum Angle ...................................................................................................................... 21 

2.6.2 Optimum Radiation ................................................................................................................ 22 

2.7  COMPARISON OF INSOLATION WITH WORLD SITES ..................................................................... 23 

2.8  SITE SELECTION FOR FEASIBILITY ............................................................................................... 23 

2.9  ISLAMKOT .................................................................................................................................... 25 

2.9.1 Tharcoal Project Near Islamkot .............................................................................................. 25 

2.9.2 Infrastructure in Islamkot ....................................................................................................... 25 

2.9.3 Maps of Islamkot .................................................................................................................... 27 

CHAPTER 3  PV TECHNOLOGIES ............................................................................................... 29 

3.1 IMPORTANT SELECTION PARAMETERS ............................................................................................ 29 

3.2 CRYSTALLINE SILICON TECHNOLOGY ............................................................................................ 30 

3.2.1 Mono-crystalline Silicon ........................................................................................................ 30 

3.2.2 Multi-crystalline Silicon ......................................................................................................... 30 

3.3 THIN FILM TECHNOLOGY ................................................................................................................ 30 

3.3.1 Amorphous Silicon ................................................................................................................. 31 

3.3.2 Cadmium Telluride (CdTe) .................................................................................................... 31 

3.3.3 Copper Indium (Gallium) Diselenide (CIS or CIGS) ............................................................ 32 

3.4 TECHNOLOGY SELECTION FOR VLS-PV ......................................................................................... 32 

3.5 WORLD’S LARGEST THIN FILM VLS-PV PLANTS .......................................................................... 33 

3.6 INSTALLATION AREA FOR A 10 MW SYSTEM ................................................................................. 33 

CHAPTER 4  VLS-PV ELECTRICITY ESTIMATIONS ............................................................ 35 

4.1  PHOTOVOLTAIC GEOGRAPHICAL INFORMATION SYSTEM (PVGIS)............................................ 35 

4.1.1 PVGIS Database ..................................................................................................................... 35 

4.1.2 PVGIS for Islamkot ................................................................................................................ 36 

4.1.3 Static Systems Electricity Estimation .................................................................................... 37 

4.1.4 Two Axis Tracking Systems .................................................................................................. 40 

CHAPTER 5  VLS-PV ECONOMICS ............................................................................................. 42 

5.1 IMPORTANT ECONOMIC PARAMETERS ............................................................................................ 42 

5.2 CAPITAL COST OF INSTALLATION ................................................................................................... 42 

5.3 ELECTRICITY PRICE ......................................................................................................................... 44 

5.4 POWER CRISIS IN PAKISTAN ............................................................................................................ 45 

5.4.1 Installed Sources of Generation in Pakistan .......................................................................... 45 

5.4.2 Furnace Oil a Problem for Pakistan ....................................................................................... 45 

5.5 SUBSIDIES IN TARIFFS ..................................................................................................................... 46 

CHAPTER 6  SOCIO-ECONOMIC IMPACTS ............................................................................. 48 

6.1  CREATION OF INDUSTRIES AND LOCAL MARKET ........................................................................ 48 

6.2  DESALINATION ............................................................................................................................ 49 

6.3  AGRICULTURAL DEVELOPMENT .................................................................................................. 49 

6.4  JOB CREATION ............................................................................................................................. 50 

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6.5  TECHNOLOGY TRANSFER ............................................................................................................ 51 

6.6  GRASSLAND AND FORESTATION.................................................................................................. 51 

CHAPTER 7  CONCLUSIONS AND RECOMMENDATIONS .................................................. 53 

7.1  CONCLUSIONS .............................................................................................................................. 53 

7.2  FUTURE WORK ............................................................................................................................ 53 

REFERENCES ........................................................................................................................................ 54 

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List of Figures

FIGURE 2-1: 550/220 KV TRANSMISSION NETWORK ................................................................................ 24 

FIGURE 4-1: ELECTRICITY GENERATED FOR STATIC SYSTEM ................................................................... 38 

FIGURE 4-2: IRRADIATION FOR STATIC AND TRACKING SYSTEMS ............................................................ 41 

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List of Tables TABLE 1-1: GLOBAL IRRADIATION IN THE WORLD DESERTS ........................................................................ 2 

TABLE 1-2: KINDS OF DESERTS ................................................................................................................... 3 

TABLE 2-1: AVERAGE SOLAR INSOLATION .................................................................................................. 8 

TABLE 2-2: CLEAR SKY INSOLATION ........................................................................................................... 9 

TABLE 2-3:MIDDAY INSOLATION .............................................................................................................. 10 

TABLE 2-4: DIRECT NORMAL RADIATION ................................................................................................. 11 

TABLE 2-5: SURFACE ALBEDO ................................................................................................................... 12 

TABLE 2-6: CLEARNESS INDEX .................................................................................................................. 13 

TABLE 2-7: DAYLIGHT HOURS ................................................................................................................... 14 

TABLE 2-8: DECLINATION .......................................................................................................................... 15 

TABLE 2-9: RELATIVE HUMIDITY ............................................................................................................... 16 

TABLE 2-10: ATMOSPHERIC PRESSURE ...................................................................................................... 17 

TABLE 2-11: PRECIPITATION ...................................................................................................................... 18 

TABLE 2-12: AIR TEMPERATURE ............................................................................................................... 19 

TABLE 2-13: EARTH SKIN TEMPERATURE .................................................................................................. 20 

TABLE 2-14: OPTIMUM ANGLE ................................................................................................................... 21 

TABLE 2-15: OPTIMUM RADIATION ............................................................................................................ 22 

TABLE 2-16: WORLD LARGEST PHOTOVOLTAIC PLANTS .......................................................................... 23 

TABLE 3-1: COMPARISON BETWEEN PV TECHNOLOGIES .......................................................................... 32 

TABLE 3-2: THIN FILM VLS-PV PLANTS ................................................................................................... 33 

TABLE 4-1: INSOLATION COMPARISON WITH MIDEAST ............................................................................. 36 

TABLE 4-2: ELECTRICITY ESTIMATIONS FOR STATIC SYSTEM .................................................................. 37 

TABLE 4-3: STATIC SYSTEM WITH OPTIMUM ANGLES .............................................................................. 39 

TABLE 4-4: ELECTRICITY ESTIMATIONS FOR 2- AXIS TRACKING SYSTEM ............................................... 40 

TABLE 5-1: CAPITAL COST FOR A 10 MW SYSTEM ................................................................................... 43 

TABLE 5-2: INSTALLED SOURCES OF GENERATION ................................................................................... 45 

TABLE 5-3: SUBSIDIES IN TARIFFS ............................................................................................................. 47 

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Abstract This thesis conceptualizes VLS-PV systems for electricity generation. A 10-MWe

VLS-PV system is targeted for installation in deserts of Pakistan. The deserts

considered for site selection were Thar, Cholistan, Northern Kharan and Southern

Kharan. The parameters for site optimization were solar insolation, number of sunny

days per year (290-300), metrological conditions, proximity to infrastructure (electric

grid, industry, water, etc). NASA’s database which contains 22 years (1983-2005)

averaged solar and metrological data is used for all sites. Based on this database all

the sites showed a great potential for VLS-PV systems but Islamkot (Thar desert) was

chosen due to its better proximity to infrastructure. The technologies evaluated were

crystalline silicon and the thin-film. The technology selected was thin-film PV as its

cost per kWe was ¼ of crystalline silicon PV modules. The land area for the system

was around 0.5 km2. The power generation estimation was done with the PVGIS

solar calculator provided by European Joint Research Centre. The total cost of the

system came to be Rs. Million 1,534 (m$ 18.02). Electricity price (without storage

options) came out to be Rs. 8.74 ($10.0 cents) per kWh which is highly competitive in

comparison to fossil fuels based plants. VLS-PV can become one of the solutions in

Pakistan to resolve the energy crisis. It is an integrated concept which includes the

energy security, climate change protection, drinking water production and other socio-

economic developments. Future work includes exploration of new sites for VLS-PV

and feasibility of energy storage options like fuel cells and battery storage

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Nomenclature

Subscripts

VLS-PV Very Large Scale Photovoltaic Systems

SSE Surface Meteorology and Solar Energy

RYK Rahim Yar Khan

CdTe Cadmium Telluride

PVGIS Photovoltaic Global Information System

JRC Joint Research Centre

1

Chapter 1 Introduction

Pakistan is a country rich of solar energy having a great potential for Very Large

Scale Photovoltaic (VLS-PV) systems. The objective of this project is to develop the

feasibility of such systems for various areas of Pakistan. The key factors included are

site selection, financial, environmental, technical, and socio-economics. In Pakistan

we are facing the worst ever crisis of energy, the need of hour is to look for various

options and solar energy is a one solution.

1.1 Energy and Its Needs

Fossil fuels are depleting, it is estimated that at the end of this century fossil fuels will

no longer be able to meet our demands. They are also creating environmental

problems globally, as they are emitting greenhouse gases at substantial level. Now

people have started to think seriously about renewable and environmental friendly

sources of energy. Solar energy is one such renewable as our earth receives its

unbelievable supply in one minute to meet the world’s energy demands for a full year.

Fossil fuels are not economical as well particularly for a developing country like

Pakistan. Solar energy is most abundant and widely distributed source of energy in

our country. It is ideally located in the sun-belt to receive solar energy. The number of

clear sunny days varies from 250 in the Northern areas to about 300 days in the most

part of rest of country [1]. Baluchistan and the arid deserts of Pakistan receive best

sunshine; we can make use of this sunshine by VLS-PV.

1.2 Very Large Scale Photovoltaic Systems

It is a PV system ranging from 10MW to several GWs, consisting of one plant, or an

aggregation of plural units distributed in same district operating in harmony with each

other. Solar energy has a very low density. For large scale production of electricity

area requirement is very large. One third of the land surface of earth is covered by dry

deserts and high level insulation (in-coming solar radiation), where a lot of space is

2

available. If we use small portion of deserts, approximately 4%, the resulting energy

would be equal world energy consumption.

A rough examination was made to examine the desert potential under the assumption

of a 50% space factor for installing PV modules on the desert surface as firs

evaluation. The electricity production would be 7,491 × 1021 J, which means a level of

almost 17 times the world primary energy supply (0,433 × 1021J in 2002). These are

hypothetical values, ignoring the presence of loads near deserts. Nevertheless, these

values give us an idea about the potential of deserts.

Deserts are extremely dry places, having high daytime temperature, particularly in

summer. Moisture contents are very small, no pollutants present in air, so these places

receive maximum solar energy. VLS-PV systems are already feasible; PV systems

with capacity greater than 10MW were connected to public grid in 2006. This concept

is yet in its initial stage. These systems are modular in nature; capacity can be

enhanced with the increase in demand. Generally space is left for new modules [2].

1.3 Desert Potential

Deserts are the high irradiation and unutilized areas in the world. The deserts located

on higher latitude have high irradiation. Theoretically, PV systems installed in Gobi

desert with 50% space factor has potential to generate energy as much as the recent

world energy supply. Table 1.1 shows the global irradiation in the various deserts of

the world [3].

Table 1-1: Global irradiation in the world deserts

Major Deserts Global Irradiation [kWhr/m2/year]

Sahara (Mauritania) 7.36

Negev 5.31

Thar (Pakistan and India) 5.96

Sonoran ( Mexico) 5.47

Great Sandy (Australia) 8.92

Gobi (China) 4.67

Tokyo (Japan) 3.47

3

1.4 Kinds of Deserts

Generally as we imagine a desert, a picture of sand floats in our mind. A desert is not

only a sand desert; it may be a rock desert, grave desert and so on. Sand desert is one

fifth of desert area. Gravel desert is the best area to install Very large scale photo

voltaic systems, because of lowest sand dune and sand storm cause minimum damage

[4].

Table 1-2: Kinds of Deserts

Rock desert Low animal, low grass, a few pines grow in little water area

Gravel desert Consists of small rocks, a few plants exist

Dirt desert As grain is very small, rainwater does not seep into ground.

Sand desert Presence of sand dunes

Salt desert Irrigation on large scale causes salt injury

1.5 Deserts in Pakistan

Main deserts of Pakistan are [5]:

1. Thar Deset

2. Cholistan Desert

3. Kharan Desert

1.5.1 Thar Desert

The origin of the arid Thar desert is a controversial subject. Some consider it to be

only 4000 to 10,000 years old, whereas others state that aridity started in this region

much earlier. Thar Desert is shared between Pakistan and India, it is 7th largest desert

in the world. It covers 446,000 square kilometers in Pakistan. The desert covers

Eastern Sindh province and the Southeastern portion of Punjab Province. About 10%

of this region is composed of sand dunes 90% of craggy rock forms, inter-dunal and

fixed dune areas.

4

1.5.2 Cholistan Desert

The word Cholistan is derived from 'Cholna' which means moving. The people of

Cholistan lead a semi-nomadic life, moving from one place to another in search of

water and fodder for their animals. The Cholistan starts some 30 kilometers from

Bahawalpur and is spread over an area of some 16,000 km2 and extends up to the

Thar Desert in the Sindh province. It is presently inhabited by about 100,000 semi-

nomads live in the desert, mostly as camel and goat herders

1.5.3 Kharan Desert

The Kharan Desert, also known locally as the "Sandy Desert", is located in northwest

Baluchistan. The moving dunes reach the height of 15 to 30 meters. This desert was

used for nuclear test by Pakistani scientists. Population in these areas is very low and

average rainfall throughout this desert is less than 100mm.

These deserts have tropical climate having great potential for Very Large Scale

Photovoltaic (VLS-PV) systems.

1.6 Environmental Aspects

Since the industrial revolution, man has achieved a dramatic growth and the life has

become more convenient and comfortable. Total energy consumption has increased

along with economic and population growth. At the same time, various environmental

problems associated with human activities have become seriously dangerous.

In order to achieve the goals of sustainable development, it is essential to minimize

consumption of finite natural resources and to mitigate the environmental burden

within nature’s restorative capacity.

Greenhouse gas emissions impact will be far from acceptable level in the future. Use

of fossil fuels for electricity generation is a major contributor to global warming.

VLS-PV systems provide environment friendly energy as there is no emission of

greenhouse gases during operation. So, we can meet our energy demands to sustain

economic growth without damaging the natural environment.

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1.7 VLS-PV and other Renewable Resources

VLS-PV is a technology which is most suited to deserts. Generally 1GW plant

requires in the order of 10 km2 land area, preferably of low cost and high insolation

level to get most suitable economics. Both of requirements are in general met by the

deserts. However, it is important to realize that VLS-PV is not the only available

option of renewable energy. One of the other leading candidates is the wind energy.

According to a US study Pakistan has the potential to produce 50,300 MW of wind

energy which is more than two and half times our current power producing capacity

of nearly 19,500 MW [6]. The wind energy is available all the 24 hours and it is not

affected by the clouds as well. VLS-PV can be used in conjunction with wind farms to

increase the availability factor. It will also cut down the storage requirement and

provide a more reliable energy to grid.

1.8 VLS-PV in Future

Solar energy, PV technologies and other renewable energy resources will help attain

economic, environmental and social objectives in the 21st century; it will play a

critical role to achieve sustainable development. In order to increase the transition to

global energy system, it is important to orient large and increasing investment towards

the renewable energy. If investment continues in conventional energy as usual,

societies will be locked into energy system incompatible with sustainable

development and one that further increase the risks of climate change.

VLS-PV is a project which has yet not been experienced to a large extent in the

world. In order to promote it we need to establish policies for developing markets,

expansion of financial options and development of required capacity. Selected site for

VLS-PV should have infrastructure, access to long distance power transmission,

human and financial resources.

6

Chapter 2 Site Selection

Site selection is the first and the very essential step for solar system installation and its

design procedure. Even the most carefully planned solar system doesn’t work

satisfactory, if the location wasn’t chosen properly. It is critical that the modules are

exposed to sunlight for proper day hours. The selected site should have good

insulation, metrological conditions and other desired features.

2.1 Parameters for Site Selection

Following are the important parameters for site selection.

• Sparsely Populated Areas

• Proximity to Infrastructure

• Solar Insolation

• No of Sunny Days

• Meteorological Conditions

2.2 Probable Sites in Pakistan

Pakistan is ideally located in the sun-belt to receive solar energy. The energy is

widely distributed and abundantly available. The number of clear sunny days varies

from 250 in the Northern areas to about 290 to 300 days in the most part of country

[1]. Solar insolation received by country is very encouraging for VLS-PV systems.

Northern areas receive less no of sunny days so they are not feasible for VLS-PV

systems. Most part of Punjab is a populated area and land is used for agriculture. As

this project is about the desert areas of Pakistan we consider the sites for VLS-PV

only in these areas. Desert areas of Pakistan receive world’s best sunshine; these are

thinly populated as well. So these are the best choices for installation of VLS- PV

systems.

7

Following are the probable sites desert areas of Pakistan:

1. Gwadar ( Southern Kharan)

(25.33˚N, 62.33˚E)

2. Quetta (Northern Kharan)

(30.06˚N, 67.16˚E)

3. Islamkot (Thar)

( 24.70˚N, 70.18˚E)

4. Rahim Yar Khan (Choolistan) (28.36˚N, 70.75˚E)

2.3 NASA Database

The database of NASA has been used for the listed sites. NASA, through its Science

Mission Directorate, has long supported satellite system and research providing data

important to the study of climate and climate processes. The data include long term

estimates of meteorological quantities and surface energy fluxes.

Datasets and methodologies called Surface Meteorology and Solar Energy (SSE) has

been formulated to increase commercial use of Photovoltaic systems. SSE has passed

through different versions; its 6th one is used in this project. This version contains

monthly averaged data from 22 years (July 1983 through June 2005) [7].

8

2.4 Solar Data for Listed Sites

2.4.1 Insolation on a Horizontal Surface

It is the amount of total radiation on the horizontal surface of the earth. It is also

referred to as global horizontal radiation. It is the main parameter which affects the

generation cost of PV systems. Table 3.1 shows that annual average of solar

insolation is best for Quetta. All the other sites get almost an equal average amount of

insolation. The values are low in last and starting 2 months of year as we have winter

season in these months.

Units

kWh/m2/day

Table 2-1: Average Solar Insolation

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 3.92 3.61 4.05 3.65

FEB 4.61 4.46 4.63 4.46

MAR 5.22 5.34 5.49 5.13

APR 6.10 6.23 6.41 6.11

MAY 6.40 6.94 6.83 6.82

JUN 6.46 7.14 6.53 6.86

JUL 5.88 6.67 5.46 6.41

AUG 5.58 6.21 5.17 5.89

SEP 5.36 5.76 5.25 5.26

OCT 5.00 4.99 4.75 4.58

NOV 4.19 4.08 4.05 3.77

DEC 3.59 3.42 3.74 3.39

ANNUAL AVG 5.19 5.40 5.19 5.19

9

2.4.2 Clear Sky Insolation

It is the amount the amount of solar radiation incident on the horizontal surface of

earth when cloud cover is less than 10%. Table 2.2 shows that it is lowest for Rahim

Yar Khan, highest for Quetta and almost equal for other two sites.

Units

kWh/m2/day

Table 2-2: Clear Sky Insolation

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 4.44 4.47 4.28 3.90

FEB 5.13 5.64 4.90 4.86

MAR 5.95 6.67 5.71 5.53

APR 6.54 6.91 6.55 6.22

MAY 6.53 7.30 7.02 6.82

JUN 6.65 7.30 7.03 6.88

JUL 6.35 7.10 6.72 6.63

AUG 6.12 6.48 6.34 6.00

SEP 5.61 5.84 5.68 5.31

OCT 5.09 5.05 4.86 4.58

NOV 4.38 4.36 4.15 3.80

DEC 4.01 3.95 3.93 3.54

ANNUAL AVG 5.56 5.92 5.60 5.34

10

2.4.3 Midday Insoltaion on a Horizontal Surface

It is the amount of radiation incident on the horizontal surface. It is calculated at solar

noon for 1.5 hours. It gives us an idea about insolation at noon timings that is around

12 pm. Table 2.3 shows that it is almost equal for all the sites. Each monthly averaged

value is evaluated as the numerical average of the 3-hourly values, one per day, at the

time (GMT) closest to local solar noon. The time (GMT) used is within 1.5 hours of

local solar noon.

Units

kW/m2

Table 2-3:Midday Insolation

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 0.55 0.48 0.55 0.50

FEB 0.62 0.56 0.60 0.56

MAR 0.67 0.64 0.70 0.65

APR 0.74 0.75 0.79 0.76

MAY 0.76 0.82 0.82 0.82

JUN 0.78 0.82 0.76 0.79

JUL 0.73 0.76 0.64 0.75

AUG 0.71 0.73 0.63 0.73

SEP 0.68 0.72 0.67 0.68

OCT 0.64 0.67 0.65 0.64

NOV 0.55 0.56 0.57 0.55

DEC 0.50 0.49 0.53 0.49

ANNUAL AVG 0.66 0.67 0.65 0.66

11

2.4.4 Direct Normal Radiation

It is the amount of solar radiation incident on the surface oriented normal to solar

radiation for a given month. In this case maximum radiation is absorbed as modules

are placed perpendicular to solar radiation. Table 2.4 shows that it is maximum for

Quetta and almost equally good for the other sites.

Units

kWh/m2/day

Table 2-4: Direct Normal Radiation

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 5.64 5.98 5.83 5.61

FEB 5.77 6.36 5.70 5.97

MAR 5.51 6.38 5.98 5.67

APR 6.06 6.66 6.63 6.28

MAY 6.03 7.21 6.85 6.91

JUN 5.99 7.31 6.13 6.75

JUL 5.05 6.55 4.35 6.03

AUG 4.90 6.30 4.19 5.59

SEP 5.36 6.69 5.09 5.43

OCT 6.13 7.00 5.44 5.64

NOV 5.93 6.86 5.42 5.47

DEC 5.26 6.05 5.49 5.43

ANNUAL AVG 5.63 6.61 5.60 5.90

12

2.4.5 Surface Albedo

It is the ratio of solar energy reflected by the surface of earth to the solar energy

incident on the surface of earth. Table 2.5 shows that it is highest for Islamkot; it

shows that minimum energy is absorbed by surface due to hot and dry terrain.

Units

dimensionless

Table 2-5: Surface Albedo

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 0.13 0.14 0.24 0.19

FEB 0.12 0.14 0.24 0.18

MAR 0.12 0.14 0.25 0.17

APR 0.13 0.20 0.26 0.19

MAY 0.13 0.20 0.28 0.22

JUN 0.15 0.22 0.30 0.25

JUL 0.16 0.22 0.28 0.24

AUG 0.16 0.22 0.25 0.20

SEP 0.13 0.20 0.22 0.18

OCT 0.12 0.19 0.20 0.16

NOV 0.12 0.21 0.22 0.17

DEC 0.12 0.17 0.24 0.18

ANNUAL AVG 0.13 0.18 0.24 0.19

13

2.5.6 Insolation Clearness Index

It is the ratio of amount of solar radiation incident on the horizontal surface to the

incoming top of atmosphere solar radiation. It is very good in deserts and other arid

places because of no air pollutants and low humidity in these areas. Table 2.6 shows

that it is almost equal for all the listed sites.

Units

dimensionless

Table 2-6: Clearness Index

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 0.58 0.61 0.59 0.58

FEB 0.58 0.62 0.57 0.59

MAR 0.56 0.60 0.58 0.56

APR 0.58 0.60 0.61 0.59

MAY 0.57 0.62 0.61 0.61

JUN 0.57 0.62 0.58 0.60

JUL 0.52 0.59 0.49 0.57

AUG 0.52 0.59 0.48 0.55

SEP 0.55 0.62 0.54 0.55

OCT 0.60 0.64 0.56 0.57

NOV 0.60 0.65 0.57 0.57

DEC 0.57 0.62 0.57 0.58

ANNUAL AVG 0.57 0.61 0.56 0.58

14

2.4.7 Daylight hours

These are the number of hours between sunrise and sunset. It is a very important

parameter because it gives us an idea about availability of solar energy in the 24

hours.

Units hours

Table 2-7: Daylight hours

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 10.7 10.4 10.8 10.5

FEB 11.3 11.1 11.3 11.2

MAR 12 11.9 12 12

APR 12.7 12.9 12.7 12.8

MAY 13.3 13.6 13.3 13.5

JUN 13.6 14 13.6 13.9

JUL 13.5 13.8 13.5 13.7

AUG 13 13.2 13 13.1

SEP 12.3 12.3 12.3 12.3

OCT 11.6 11.4 11.6 11.5

NOV 10.9 10.6 10.9 10.7

DEC 10.6 10.2 10.6 10.3

AVG 12.2 12.1 12.1 12.1

15

2.4.8 Declination

It is the angular distance of sun north (positive) or south (negative) of the equator.

Declination varies through the year from 23.45˚ north to 23.45 south and reaches the

maximum / minimum at the southern / northern summer solstices. The determination

of monthly averaged declination for each month is based on the "monthly average

day" (SSE Methodology).

Units degrees

Table 2-8: Declination

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GAWDAR QUETTA ISLAMKOT RYK

JAN -20.70 -20.70 -20.70 -20.70

FEB -12.30 -12.30 -12.30 -12.30

MAR -1.80 -1.79 -1.81 -1.81

APR 9.71 9.71 9.70 9.70

MAY 18.80 18.80 18.80 18.80

JUN 23 23 23 23

JUL 21.20 21.20 21.20 21.20

AUG 13.70 13.70 13.70 13.70

SEP 3.08 3.08 3.09 3.09

OCT -8.45 -8.46 -8.44 -8.44

NOV -18.10 -18.10 -18.10 -18.10

DEC -22.80 -22.80 -22.80 -22.80

16

2.5 Meteorological Data for Listed Sites

2.5.1 Relative Humidity

Humidity is the amount of water vapor in the air. It regulates the temperature by

absorbing radiations both from the sun and earth. Relative humidity is the ratio of

water content of air in normal conditions to water contents at its saturation. Saturated

air has relative humidity of 100%. Table 2.9 shows the relative humidity calculated

from the air temperature at 10 m above the surface of the earth.

Units

percent

Table 2-9: Relative humidity

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 49.5 52.4 31.9 38

FEB 49.3 45.3 28.8 31.8

MAR 49.3 36.6 27 25

APR 45.4 27.6 32.9 25.9

MAY 47.1 21.2 43.5 29.6

JUN 53.9 27.3 57.8 43.1

JUL 69.1 45.4 68.4 59.5

AUG 70.7 50.3 68.2 65.5

SEP 60.4 30.6 55.4 50.6

OCT 45.9 22 35.8 28.3

NOV 44.3 27.7 27 27

DEC 47.3 42.3 29.4 32.7

ANNUAL AVG 52.7 35.7 42.3 38.1

17

2.5.2 Atmospheric Pressure

It is exerted by the weight of the air above any point on the earth surface. It has

maximum value at the sea level but reduces with latitude. Standard sea level pressure

is 1atm or 101.35 kilopascals. It is very low for Quetta as it is at high latitude

(6,597ft) comparing to other sites.

Units kPa

Table 2-10: Atmospheric pressure

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 98.7 84 100 99.4

FEB 98.6 83.9 100 99.1

MAR 98.3 83.8 100 98.8

APR 97.9 83.7 100 98.4

MAY 97.5 83.5 99.6 97.9

JUN 97 83.1 99.3 97.5

JUL 97 83.1 99.2 97.5

AUG 97.2 83.3 99.5 97.8

SEP 97.7 83.6 99.8 98.2

OCT 98.2 84 100 98.8

NOV 98.6 84.2 100 99.2

DEC 98.8 84.2 100 99.5

ANNUAL AVG 97.9 83.7 100 98.5

18

2.5.3 Precipitation

It is the condensation of atmospheric water vapor that is pulled down by gravity on

the earth surface for a specific period of time. Precipitation is very low in deserts

making them the most suitable places for VLS-PV. Table 2.11 shows that it is lowest

for Gwadar and highest for Islamkot among the listed sites. In Islamkot and Rahim

Yar Khan there is a rainy season in July and August, so precipitation is high in these 2

months. In Islamkot precipitation is lowest in all the other months except Monsoon

season.

Units mm/day

Table 2-11: Precipitation

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 0.54 0.65 0.15 0.23

FEB 0.43 0.82 0.17 0.41

MAR 0.52 1.06 0.1 0.47

APR 0.19 0.61 0.13 0.33

MAY 0.11 0.27 0.23 0.3

JUN 0.19 0.31 1.68 0.76

JUL 0.8 1.17 4.34 2.56

AUG 0.39 0.99 3.18 2.04

SEP 0.12 0.3 1.52 0.67

OCT 0.14 0.13 0.43 0.2

NOV 0.12 0.12 0.06 0.07

DEC 0.45 0.46 0.08 0.16

ANNUAL AVG 0.33 0.57 1.01 0.68

19

2.5.4 Air Temperature at 10 m above the Surface of Earth

Temperature values are calculated at 10 m above the surface of earth. Table 2.13

shows that there is variation in temperature in different months due to seasonal

variations for all sites except Gwadar. In Gwadar air temperature remains almost

same throughout the year. Average air temperature is lowest for Quetta and is almost

same for the rest of the sites.

Units

degree Celsius

Table 2-12: Air Temperature

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 18.7 4.98 20.1 13.8

FEB 19.5 7.11 22.3 16.4

MAR 22.8 12.4 27.4 22.6

APR 26.7 18.6 30.7 27.9

MAY 29.6 23.8 32 31.8

JUN 30.4 27 31.2 33.2

JUL 28.4 26.6 29.6 31.6

AUG 27.1 25.2 29 30

SEP 26.9 23.1 29.7 29.4

OCT 26.6 17.7 29.7 26.3

NOV 23.8 12.3 26 20.8

DEC 20.5 7.45 21.8 15.7

ANNUAL AVG 25.1 17.2 27.5 25

20

2.5.5 Earth Skin Temperature

It is the temperature of the interface between the earth’s surface and atmosphere. Data

over the oceans is sea surface temperature. Table 2.13 shows that this parameter has

high value for Islamkot as it is very hot and dry location. It is lowest for Quetta and

almost same for the remaining sites.

Units

degrees Celsius

Table 2-13: Earth skin temperature

22 YEARS AVERAGE DATA (1983-2005)

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 20.6 6.26 22.7 14.9

FEB 21.6 8.96 25.7 18.4

MAR 24.8 15.3 32 25.8

APR 28.8 23 36 32

MAY 32.2 28.8 36.9 36.3

JUN 33.6 32.4 35.3 37.4

JUL 31.7 32.2 32.8 35.2

AUG 30.4 30.2 31.9 32.8

SEP 30.1 27.8 33.5 32.2

OCT 28.5 21 33.2 28.4

NOV 25.4 14.1 28.7 21.9

DEC 22.2 8.52 23.9 16.4

ANNUAL AVG 27 20.8 31.1 27.7

21

2.6 Parameters for Tilted Solar Panels

2.6.1 Optimum Angle

It is the angle relative to horizontal for which the maximum solar radiation is

received. Table 2.14 shows that average angle is close to the latitude of the locations.

It is very important parameter for installation PV panels. In static systems modules are

inclined at optimum angle to get maximum possible solar radiation.

Units

degrees

Table 2-14: Optimum angle

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 49 54 48 52

FEB 41 46 40 44

MAR 26 32 26 29

APR 12 16 11 14

MAY 0 2 0 1

JUN 0 0 0 0

JUL 0 0 0 0

AUG 6 9 6 8

SEP 20 26 19 23

OCT 37 42 35 39

NOV 47 53 45 49

DEC 51 57 51 55

ANNUAL AVG 23.9 27.9 23.3 26

22

2.6.2 Optimum Radiation

It is the amount of radiation incident on a surface tilted at the optimum angle relative

to the horizontal and pointed to the equator.

Units

kWh/m2/day

Table 2-15: Optimum radiation

MONTHS GWADAR QUETTA ISLAMKOT RYK

JAN 5.32 5.51 5.46 5.27

FEB 5.66 5.95 5.64 5.73

MAR 5.59 5.99 5.88 5.62

APR 6.07 6.28 6.38 6.13

MAY 6.37 6.91 6.8 6.79

JUN 6.43 7.1 6.5 6.83

JUL 5.85 6.64 5.43 6.38

AUG 5.52 6.24 5.07 5.9

SEP 5.53 6.16 5.4 5.51

OCT 5.88 6.33 5.48 5.52

NOV 5.49 6.06 5.18 5.15

DEC 5.06 5.59 5.23 5.15

ANNUAL AVG 5.73 6.23 5.70 5.83

23

2.7 Comparison of Insolation with World Sites

World’s largest PV plants are listed in the Table 2.16. Large scale photovoltaic is a

new concept as all of the given plants have been constructed in the recent years [7, 8].

Table 2.16 shows that solar insolation in all of sites is less as compared to listed sites

in Pakistan. Data comparison shows that all the listed sites have potential for VLS-PV

systems.

Table 2-16: World Largest Photovoltaic Plants

Country Site Power

Capacity (MW)

Annual Avg

Insolation

(kwh/m2/day)

Constructed

CANADA SARNIA 80 3.67 2009-2010

SPAIN OLMEDILLA 60 4.44 2008

GERMANY STRABRICKEN 54 3.19 2009

PORTUGAL MOURA 46 4.69 2008

CHINA XUZHOU 20 4.11 2010

2.8 Site Selection for Feasibility

All the listed sites show potential for installation of VLS-PV systems. They show

good insolation, meteorological conditions and the other desired features. At this

stage one site has to be selected for feasibility. We can not neglect anyone of these

sites on the basis of natural conditions. The site is selected on the basis of available

infrastructure which includes transmission lines network, water, transportation and

other facilities.

Figure 2.1 shows the transmission network in Pakistan [10]. Although a good

infrastructure is being developed in Gwadar but yet not connected to the national grid.

There is a 220 kV substation in Quetta but it is of small capacity. A 500 kV substation

is under construction in Thar coal site which is nearest to Islamkot, it will be

connected to national grid very soon.

24

Figure 2-1: 550/220 KV Transmission Network

25

None of the site can be ignored on the basis of natural conditions except Rahim Yar

Khan as dust storms are the major hurdles in this site.

This feasibility study has been made for Islamkot. Security situation is much better

here and as a very good infrastructure exists in this region. It is the nearest town to

Thar coal site and many development programs going on in this region. Thar region is

the main focus of both Provincial and Federal Government.

2.9 Islamkot

Islamkot is a town in Tharparkar district, in Sindh. Its population is about 12,426

(2004 estimate). It is about 70m above the sea level. It is connected to two large cities,

Hyderabad (192 miles in northwest) and Karachi (199 miles north).

2.9.1 Tharcoal Project Near Islamkot

Tharcoal field is located between latitudes 24˚15 ΄ and 25˚45΄ N and longitudes 69˚ 45

and 70˚45΄ E. As a result of wide spread drilling over an area of 9000 km2, a total of

175 billion tons of coal resource potential has been assessed. Geological Survey of

Pakistan has selected four blocks near Islamkot for exploration and assessment of coal

resources. The importance of Islamkot has been increased because it is the nearest

town to Tharcoal field.

2.9.2 Infrastructure in Islamkot

As Islamkot is the site near Tharcoal field, government is paying special attention to

improve the infrastructure [9].

Transportation

Islamkot has a road connection with Karachi via Mithi-Badin-Thatta and Naukot-

Mirpurkhas-Hyderabad. A railway link exists from Hyderabad up to Naukot which is

100 km away from Islamkot. Pakistan railway has conducted the feasibility study of

railway line at Tharcoal field to facilitate the transportation. The railway route has

been approved by the Chief Minister, Sindh .

26

Airport

Islamkot International Airport is under construction in Islamkot by Civil Aviation

Authority of Pakistan.

Thar Lodge

The scheme for construction of 20-bedded accommodation to facilitate foreign and

local investors at Islamkot has been approved at an estimated cost of Rs. 40.978

millions, construction is in progress.

Grid

There is a grid station in Islamkot, 11 kV line emanates from Islamkot Grid Station to

Thar Coal Project. 500 kV substation was to be completed in 2010 near Islamkot but

yet its construction is in progress.

Telecommunication Optical fiber cable lying/installation of system between Mirpurkhas to Mithi

exchanges completed. 100’ high guide tower (1” dia) is to be installed at Thar coal

cite with DRS equipment. Telephone facility is available up to Islamkot

Water supply Water supply line from Mithi to Islamkot and Islamkot to coal mines (Thario

Halepoto) has been completed and water reservoir of 6 lac gallons is available at coal

mine site. 03 lac gallons / day will be available at Thar coal site.

Town Planning of Islamkot  Town Planning of Islamkot” nearest town to coalfield has also been sponsored for

rehabilitation/resettlement of the villages located within the coal field vicinity.

Displaced population will be relocated by providing them all necessary facilities in

the nearest township.

27

2.9.3 Maps of Islamkot

Maps of Islamkot will give us an idea about its importance [11]:

Map Showing Geographies of Islamkot

Map Showing Other Towns in Tharparkar District

28

Map Showing Population of Islamkot

Map Showing hot and arid Terrain of Islamkot

29

Chapter 3 PV Technologies

The basic science of Photovoltaic was discovered in 1839 when a 19 years old French

physicist Alexandre Edmond Becquerel observed light-electricity conversion. After

this different scientists contributed to development of Photovoltaic until 19th century.

In 1905 Albert Einstein made his mark with his publications on Photoelectric effect.

The commercial age of solar cells started in 1954 when Bell Laboratories, while

working on silicon semiconductors, developed Si solar cells, achieving 6% efficiency.

Early satellites were the primary use for these first solar cells.

Now we live in a new era and substantial improvements in PV technologies have been

achieved, new technologies are being introduced as well. Modules cost has been

significantly reduced in the recent years. Conversion efficiencies and life spans are

being improved to meet the future energy challenges. VLS-PV systems will be the

booster for solar cells industry in near future.

3.1 Important Selection Parameters

Following are the parameters for technology selection:

• Modules Cost

• Life Span

• Silicon Consumption

• Conversion Efficiency

• Availability

The main technologies on the basis of semiconductor materials are:

1. Crystalline Silicon Technology

2. Thin Film Technology

30

3.2 Crystalline Silicon Technology

Crystalline silicon cells are mostly used in the world due to their compactness. Their

efficiencies range from 11 to 16% (half to two third of theoretical maximum) and

their market share is 78 to 80% [12]. Crystalline silicon is a light absorbing

semiconductor in solar cells, even though it is relatively poor absorber of light and

requires several hundred microns of thickness. Nevertheless, it has proved to be

convenient because it yields stable solar cells and uses process technology developed

from huge knowledge base of microelectronic industry.

There are two types of crystalline silicon:

1. Mono-crystalline silicon

2. Multi-crystalline

3.2.1 Mono-crystalline Silicon

It is best researched solar material having best power to area ratio. Single crystal

modules are composed of cells cut from a piece of a continuous crystal. The material

forms a cylinder which is sliced into thin circular wafers. To minimize the waste, cells

may be round or they may be trimmed into other shapes. As each cell is cut from a

single crystal, it has uniform color which is dark blue [13].

3.2.2 Multi-crystalline Silicon

These are made from similar silicon material except that instead of being grown into a

single crystal, they are melted and poured into mold. As material cools, it crystallizes

in an imperfect manner, forming random crystal boundaries. Their efficiency of

energy conversion is slightly lower which merely means that size of finished module

is slightly greater per watt than most single crystal module. The cells look different

from single crystal with many variations of blue color on surface.

3.3 Thin Film Technology

It uses very thin layers of semiconductor materials deposited on metal, ceramic or

semiconductor substrate. The selected materials are all strong light absorbers and need

31

thickness in microns, so materials costs are significantly reduced. Their market share

is 18 to 20% [12]. Their efficiencies are low compared to silicon crystal but

remarkable improvements have been observed over the years.

Thin film modules are inexpensive to produce and can be produced at much faster

rates than crystalline silicon. Thin film materials can be folded into compact and

portable solar panels. These are versatile and can be incorporated into building

materials, paints and fabrics. They are light in weight, flexible and easy to integrate.

The most common types are:

1. Amorphous Silicon

2. Cadmium Telluride (CdTe)

3. Copper Indium (Gallium) Diselenide (CIS or CIGS)

3.3.1 Amorphous Silicon

It is made of amorphous or microcrystalline silicon having high absorption rate of

light than crystalline cells. A complete light spectrum can be absorbed within a very

thin layer of photo-electrically active material. A film only 1 micron thick can absorb

90% of useable solar energy.

Although it has been in production for decades but still its efficiency is less than half

of crystalline silicon, it degrades significantly as well with a long term exposure to

sunlight.

3.3.2 Cadmium Telluride (CdTe)

It uses Cadmium Telluride thin film, a semiconductor layer for absorption and

consumption of sunlight into electricity. Its efficiency has increased over the years to

about 11.2 %. This technology has been refined over the years and capable of

producing high volume, low cost modules, making widespread solar electricity a

reality [14].

The Cadmium is very toxic material but studies were carried out on this technology

by European Commission, Joint Research Centre concluded “CdTe used in PV is

environmental stable, it does not leak into atmosphere under normal conditions or

32

foreseeable accidents and therefore considered as environment safest use of

Cadmium”.

3.3.3 Copper Indium (Gallium) Diselenide (CIS or CIGS)

It has highest conversion efficiency among the other existing thin film PVs touching

to about 13% in 2010 [15]. One disadvantage in this technology is that it uses rare

earth metals that are already short in supply. Their fabrication knowledge is also

limited as compared to CdTe.

3.4 Technology Selection for VLS-PV

Table 3.1 shows a general comparison between crystalline silicon and thin film [12,

14]. It shows that prices of crystalline silicon are about 4 times higher than making it

unfeasible for very large scale PV systems. Comparison shows that conversion

efficiency is greater for crystalline PV but it has been improved for thin films as well.

15 to 40 percent more space is required for thin films but it is not a big issue as

deserts are requirement for VLS-PV.

Table 3-1: Comparison between PV Technologies Parameter Crystalline Silicon Thin Film

Module Cost (per KWe) $3,600 $760

Market Share 78-80% 18-20%

Conversion Efficiency 11-16% 11-13%

Life Span 25-30 years 25-30 years

Thickness 0.3mm 1-3µm

Availability Work in all Seasons Work in both High and Low

Intensity

Silicon Consumption High Silicon Consumption 1-2 % of Silicon Crystal

Technology

33

On the basis of parameters listed above thin film comes out to be the best choice for

VLS-PV systems. Among the different technologies in the thin film, CdTe is chosen

because a better available knowledge of technology and some additional features.

Following are the additional features:

• Superior light absorption properties resulting in high output compared to

traditional silicon modules under cloudy and diffuse light conditions such as

dawn and dusk.

• Better performance under high temperatures as modules are subjected to it

under direct sunlight

• Enhanced suitability for production of modules - high volume and low cost.

• Faster energy feedback time- fastest of all existing PV technologies.

• Low emission of carbon and no other waste production.

3.5 World’s Largest Thin Film VLS-PV Plants

Thin film is used in recently constructed world’s largest PV. Table 3.2 includes two

largest PV plants in the world constructed in 2010 [8].

Table 3-2: Thin Film VLS-PV Plants

Country Power (MW) PV Technology Constructed

Germany 80.7 Thin film (CIGS) 2010

Canada 80 Thin film (CdTe) 2010

Germany 40 Thin film (CdTe) 2008

3.6 Installation Area for a 10 MW System

We have considered a 10 MW system for developing the feasibility in Islamkot. Area

is calculated by comparison with an already operational plant in Germany.

Waldpolenz Solar Park, is a 40 MW system using thin film technology. The

installation is located in the Muldentalkeris district in the state of Sexony in eastern

Germany occupying 220 hectares of area [16] .550,000 First Solar thin film modules

34

from Cadmium Telluride (CdTe) are being used which supply 40,000 MWh of

electricity per year.

If we consider it for a 10 MW unit:

Installation area = 55 hectares

= 0.5 Km2

Thin film modules ( CdTe) = 137,000

35

Chapter 4 VLS-PV Electricity Estimations

4.1 Photovoltaic Geographical Information System (PVGIS)

PVGIS is a calculator used in this project to estimate the electricity generation. Its

latest version (PVGIS-CMSAF) is used in the calculations. It is research,

demonstration and policy-support instrument for geographical assessment of the solar

energy resources. PVGIS combines expertise from laboratory research, monitoring

and testing with geographical knowledge to analyze technical, environmental and

socio-economic factors of solar electricity generation. PVGIS is a developed by

European Joint Research Centre (JRC), Renewable Energy Unit [17].

4.1.1 PVGIS Database

It covers database of following regions:

1. European Subcontinent

2. Mediterranean region

3. Africa

4. Mid East

There are mainly two types of solar radiation sources, one is based on the ground

measurement and the other is based on the satellite measurement. PVGIS use the

satellite datasets for calculations for various locations in the world. Geo-stationary

satellite takes the picture of earth at short intervals (every 15 or 30 minutes), so they

have a very good time resolution. Polar-Orbiting satellite fly closer to earth, so space

resolution is better for them. However they don’t stay permanently over an area so

they can take couple of picture a day for a particular area. The data used for PVGIS

mainly comes from Geo-stationary satellites.

36

PVGIS datasets does not cover the region of Pakistan; it covers regions up to Iran. A

project has been launched by JRC to estimate solar radiation from the Meteostat-7

satellite over the Indian Ocean but it will take one year for its completion

4.1.2 PVGIS for Islamkot

PVGIS energy estimations are used for Islamkot by comparing it with such a site

having almost same latitude and solar insolation. Different sites of Mid East are

selected for comparison. Table 4.2 shows that the annual average insolation of Doha

is almost similar to Islamkot. Its PVGIS database and electricity estimations are used

as reference for Islamkot.

Table 4-1: Insolation Comparison with Mideast

MONTHS ISLAMKOT

( 24.70˚N, 70.18˚E)

UAE

(23.46°N, 53.73°E)

DOHA

(24.04° N,51.30°E)

JAN 4.05 3.67 3.56

FEB 4.63 4.49 4.33

MAR 5.49 4.97 4.77

APR 6.41 5.61 5.33

MAY 6.83 6.54 6.28

JUN 6.53 6.81 6.63

JUL 5.46 6.24 6.28

AUG 5.17 6.18 6.22

SEP 5.25 5.99 5.82

OCT 4.75 5.45 5.30

NOV 4.05 4.46 4.31

DEC 3.74 3.68 3.56

ANNUAL AVERAGE 5.19 5.34 5.20

37

4.1.3 Static Systems Electricity Estimation

Following are the different parameters used in PVGIS

Nominal Power of the PV Unit: 250.0 kW

Technology: Thin Film, (CdTe)

Following are the different types of losses occurring in the grid connected PVs.

Estimated Losses due to Temperature: 3.8 % (using local ambient temperature)

Estimated Losses due to Angular Reflectance Effects: 2.8 %

Other Losses (cables, inverter etc): 14 %

Combined PV Losses: 19.6 %

Table 4.2 shows the electricity generated for a horizontal static system. It shows that

energy generation is proportional to solar insolation.

Table 4-2: Electricity Estimations for Static System

FIXED SYSTEM: INCLINATION=0°, ORIENTATION=0°

MONTH DAILY ENERGY

GENERATION

(kWh)

MONTHLY ENERGY

GENERATION

(kWh)

JAN 750 23,300

FEB 901 25,200

MAR 973 30,200

APR 1,070 32,000

MAY 1,230 38,200

JUN 1,290 38,800

JUL 1,230 38,000

AUG 1,220 37,700

SEP 1,160 34,700

OCT 1,070 33,200

NOV 891 26,700

DEC 745 23,100

YEARLY AVERAGE 1,040 31,800

TOTAL FOR THE YEAR 381,000

38

Figure 4.1 shows the energy generated for a fixed system inclined at zero degree with

respect to horizontal surface. It shows generation is high in the middle of the year in

which we have summer season as well. There is a fall in energy generation in the

starting and ending months of year due to winter season.

Figure 4-1: Electricity Generated for Static System

39

Table 4.3 shows the electricity generated for a fixed system at optimum inclination

and orientation. There is almost 6 % increase in power for this system. These modules

are south oriented. Manual or automatic tilt adjustment can be made to increase the

light-electricity conversion. Optimum inclination for Islamkot is 23.1°, it shows our

assumption is reasonably good.

Table 4-3: Static System with Optimum Angles

FIXED SYSTEM: INCLINATION=23°, ORIENTATION= -1° (OPTIMUM)

MONTHS GLOBAL

IRRADIATION

(kWh/m2/day)

DAILY ENERGY

GENERATION

(kWh)

MONTHLY ENERGY

GENERATION

(kWh)

JAN 4.56 944 29,300

FEB 5.16 1,050 29,400

MAR 5.18 1,040 32,200

APR 5.33 1,060 31,800

MAY 5.89 1,160 35,900

JUN 6.01 1,180 35,400

JUL 5.79 1,130 35,200

AUG 6.06 1,180 36,700

SEP 6.15 1,210 36,200

OCT 6.17 1,220 37,800

NOV 5.47 1,110 33,300

DEC 4.69 967 30,000

YEARLY AVERAGE 5.54 1,100 33,600

TOTAL FOR THE YEAR 403,000

40

4.1.4 Two Axis Tracking Systems

These are the systems which change azimuth as well as tilt angle synchronously with

the sun. Azimuth is changed by east to west rotation in daily tracking while tilt angle

is changed as declination of sun is changed. .

Table 4.4 shows electricity generated for a two axis tracking system. There is 35%

increase in energy for two axis tracking system in comparison with horizontal static

system. It shows the importance of tracking in PV modules.

As declination of sun is changed for different seasons, tilt angle needs to be changed

accordingly. For these systems tilt angle is changed for every month. Hence

understanding the motion of sun is very essential for solar systems design and their

installation.

Table 4-4: Electricity Estimations for 2- Axis Tracking System

2-AXIS TRACKING SYSTEM

MONTHS IRRADIATION ON

MODULES

(kWh/m2/day)

DAILY ENERGY

GENERATION

(kWh)

MONTHLY ENERGY

GENERATION

(kWh)

JAN 5.87 1190.00 36,900

FEB 6.50 1310.00 36,600

MAR 6.43 1280.00 39,600

APR 6.68 1320.00 39,600

MAY 7.83 1520.00 47,200

JUN 8.30 1610.00 48,300

JUL 7.78 1510.00 46,700

AUG 7.80 1510.00 46,900

SEP 7.72 1500.00 45,100

OCT 7.86 1530.00 47,500

NOV 7.08 1410.00 42,200

DEC 6.15 1240.00 38,300

YEARLY AVERAGE 7.17 1410 42,900

TOTAL FOR YEAR 2,620 515,000

41

We have considered a 10 MW system for developing the feasibility in Islamkot.

Total units generated in one year = (250 kW module units × 4) × 10

= 20,600 MWh

Figure 4.2 shows the comparison between irradiation estimate for a fixed system

inclined at 23 degrees and a two-axis tracking system. Shape of graph is similar in

both the cases but there is a clear difference between their irradiation estimates. This

is the reason that tracking systems are preferred.

Figure 4-2: Irradiation for Static and Tracking Systems

42

Chapter 5 VLS-PV Economics

Economic evaluation is the fundamental step in the installation of any system. PV

systems were not considered economically mature a few years ago due to high

modules cost. Now the module prices have been reduced with the advent of new

technologies. Land price was one of the hurdles as its requirement is large due to low

density of solar energy. VLS-PV systems have solved this problem as deserts are used

for installation having no considerable market value. Running cost of VLS-PV

systems is low because of no fuel cost.

5.1 Important Economic Parameters

The most important economic PV parameters are

• Total Cost of Installation

• Electricity Price

• Subsidies in Tariffs

• Payback Periods

• Investments in this area

5.2 Capital Cost of Installation

Capital cost of a plant is calculated by including all the factors. Table 5.1 shows the

total cost of installation for a 10 MW VLS-PV system. Thin film technology has

reduced the modules cost to a large extent as 75% of system cost was module cost few

years ago with silicon crystal technology. Table 5.1 shows that PV modules account

about 42% of total cost.

Inverters and other equipment costs are taken from a feasibility study on 8 MW large

scale PV systems in Dunhaung, China [2]. It is a place located in the Gobi desert

which is one of difficult accessible places in the world. There is a much better

transportation available in Islamkot as compared to Dunhaung.

43

We shall have to import the thin film modules as these are not available in our market.

In Table 5.1 Import cost is merged in the overall transportation cost. This cost is also

taken from the feasibility study in Daunhaung as it is a more difficult place to access

than Islamkot our assumption is reasonable.

We assume the 100 % loan financing at 3 % compound interest rate for VLS-PV in

Islamkot. Loan is to be returned in 15 years.

Table 5-1: Capital Cost for a 10 MW System

PERCENTAGE COST ( MILLION RS)

PV MODULES ( THIN FILM) 42.55 652.84

INVERTERS 22.98 352.53

TRANSFORMERS 2.36 36.28

TEST AND MONITORING 1.67 25.77

CIVIL CONSTRUCTION 10.45 160.39

TRANSPORTATION & INSTALLATION 4.93 75.76

FEASIBILITY 4.70 72.15

MISCELLANEOUS 10.32 158.33

TOTAL 100 1534.05

44

5.3 Electricity Price

We consider a 10 MW system for price calculations:

Total Units generated from 10 MW system = (250 KW module units ×4) × 10

= (515,000 × 4) × 10

= 20.60 million units

WAPDA average tariff to consumers = Rs 5.00/ unit

Revenue generated in one year at WADA tariffs = 20.60 × 5

= Rs 103.00 millions

Operation and maintenance cost = 20 % of revenue generated per year

= Rs 20.6 millions/ year

Total amount of initial loan = Rs 1534.05 millions

Total amount of interest in 15 years = Rs 855.92 millions

Total O & M cost for 15 years= Rs 309.00 millions

Total amount to be returned= Rs 2,698.98 millions

Electricity Price = Total Amount to be returned/ Total units generated

= 2698.98/ (20.60×15)

= Rs 8.74/ unit

Note that we assumed that same of number of units will be generated every year.

Although during maintenance some of modules will not be functioning for a specific

time. As plant is modular in nature, it is not failed as a whole unit.

We have also kept the same tariff for 15 years which will increase over the years. As

operation and maintenance cost also increase every year, we assume that it will be

compensated with the increase in tariff price.

45

5.4 Power Crisis in Pakistan

Pakistan is facing a worst crisis at the moment due to shortage in supply of electricity.

Country has been facing this problem for about 3 years but still no planning is

formulated to solve the problem. Load shedding has become part of life in Pakistan.

The current situation is creating harmful effects on the whole economy. The crisis

may grow larger in future if government doesn’t take proper steps on priority basis.

5.4.1 Installed Sources of Generation in Pakistan

Table 4.1 shows the different installed sources of generation in Pakistan.

Table 5-2: Installed Sources of Generation

SOURCE OF GENERATION CAPACITY (MW)

HYDEL 6,500

FURNACE OIL 6,600

NATURAL GAS 5,800

NUCLEAR 450

COAL 150

TOTAL CAPACITY 19,500

5.4.2 Furnace Oil a Problem for Pakistan

Furnace oil prices have been increased over the years. Pakistan is suffering from this

situation as we have to generate about 33% of total installed capacity through oil.

Currently PSO has increased Furnace oil price to Rs.49567 per ton which means

Rs.50 per kg [18]. According to WAPDA and IPP agreement, the private power

producer will charge WAPDA the actual cost of fuel for which they have a direct

contract with PSO.

One kg of furnace oil on an average produces 3.8 KWh of electricity. The cost of

generating one unit of electricity is about Rs.13. Fixed cost of a thermal plant is about

Rs.3 per unit. Thus one unit of electricity produced by thermal plants is about Rs. 16

46

per unit (Transmission lines losses are not included as these were not include in VLS-

PV unit cost as well).

WAPDA tariff charged to consumer is about Rs.5 per unit. The difference between

the WAPDA tariff and furnace oil generation is about Rs.11 per unit. It is estimated

that country consumes 25 billion units of furnace oil, which means a deficit of

Billions Rupees [19]. Government does not have resources to provide this subsidy; it

is also not feasible to increase the power tariffs. Due to financial problems, payments

have been delayed to IPPS and Oil companies; as a result they have reduced their

generation. Hence generation through oil is not feasible at all for any planner.

5.5 Subsidies in Tariffs

Government should provide subsidies in Tariffs to promote the renewable energy

resources like solar and wind to achieve the grid parity. These are set for a particular

period of time usually for years. There are regulations in some countries under which

an obligation is imposed on the regional or national grid to buy the electricity

generated from solar energy at special tariffs.

Now we consider a case in which an investor invests the money on VLS-PV in

Islamkot. Table 5.3 shows, without any subsidy in tariffs payback period comes out to

be about 16 years. Government should provide subsidy in the form of feed-in tariffs to

the investors.

Instead of providing Rs 11/unit subsidy on oil based power units, government should

look for the other options. If Rs 5/unit is provided to investors in VLS-PV systems in

Islamkot, payback period is reduced to 7 or 8 years. This subsidy can be provided for

5 years or any other feasible period of time. Government should also provide tax free

zones for these systems.

47

Table 5-3: Subsidies in Tariffs

AMOUNT TO BE INVESTED= RS 1534.04 MILLIONS

NATIONAL GRID UNIT COST = RS 5

SUBSIDY

(RS/ UNIT)

PAYBACK PERIOD

(YEARS)

NONE 16.55

1.00 13.54

2.00 11.45

3.00 9.92

4.00 8.76

5.00 7.44

48

Chapter 6 Socio-Economic Impacts

Deserts are the areas with inhospitable surfaces, underground wealth, dry and hot

conditions creating difficult conditions for inhabitants. A more challenging and

realistic way is to convert these difficult conditions an opportunity for welfare of

mankind. These are areas rich of inexhaustible solar energy and other resources, we

can make use of them for socio-economic development.

VLS-PV systems have a great potential to become a driving force for these socio-

economic development. An electric market may be created in deserts which will

create many jobs for inhabitants. It may also result in industrial development and

technology transfer to these desert areas. Electricity can be used for entertainment,

education, lightning, communication, clean water production, irrigation and

agriculture.

6.1 Creation of Industries and Local Market

Creation of new industries is dependent upon the availability of energy. In Pakistan

industrial development is much slower because of lack of energy. VLS-PV systems

can enhance the pace of industrialization particularly in the desert areas. Increase in

the demand of these systems will further reduce the cost of PV modules and there will

be a worldwide booster in PV industry as well.

Mining industry can be flourished in Thar Desert through this electricity; Thar coal

region near Islamkot has 175 billion tons of coal potential and it covers the area of

9,000 Km2 [9]. VLS-PV systems in Islamkot will have an impact not only locally but

on overall economy of country as well.

Deserts of Pakistan are full of natural resources but exploration need investment and

energy. One of largest world copper deposits is found in Reko Diq, a giant mining

project in Chaghi, Kharan Desert. Energy is needed to get full benefits from these

resources; VLS-PV systems can provide this energy to explore these resources.

49

With a solid strategy for implementing very large scale photovoltaic solar systems,

the local market will create enough need to justify local manufacturing of solar

system components such as [2]:

• Assembly of PV solar panels

• Manufacturing of solar cells

• Manufacturing of silicon

• Installation, building and services

6.2 Desalination

The need of water is increasing in all parts of world due to domestic, agricultural,

industrial and tourist pressures. The population growth is also increasing in dry

regions of the world including Pakistan. In our country food demand is increasing

with the population and there is an intensive stress on the water resources which are

already short. It is also creating political problems causing tensions between the

provinces.

In many regions of world ground water is falling by several meters every year, it is a

problem in Thar Desert as well. When rainfall is small in a particular year wells get

dried. Salinity is also a big problem in the world and it is big threat to agriculture in

Pakistan as well. In Mithi (Thar), the salinity of underground water is at 6000 part per

million (PPM), much above the 500 PPM, approved by the WHO fit for drinking [20].

Additionally due to rapid industrialization, dumping industrial waste directly into

rivers without treatment has affected the quality of water. Most diseases and fatalities

in the developing countries are due to lack of clean water. The availability of clean

water is a basic necessity of human beings.

6.3 Agricultural Development

Agriculture is the largest economic sector in developing regions like Pakistan. To

improve and strengthen the agriculture is a first step in developing arid and semi arid

regions. Agriculture is the largest user of water in the world. The situation will get

worse with the rise of population because use of fresh water is proportional to

50

population. According to WHO standards agriculture also requires quality water,

irrigation with polluted water will ultimately transfer the diseases to human beings.

Salt accumulation and accompanying desertification that stems from improper

irrigation under arid and semi arid climates is a serious problem. High quality deep

ground water is not rechargeable and thus similar to fossil resources such as oil. At

the time desalinated sea water and brackish rechargeable shallow ground water may

be alternative water resources. Secondary treated water from municipal is another

choice. Water desalination on large scale for agriculture requires energy and finance.

The energy source for this process will be a huge issue in the future. It is not the right

option to run the desalination plant with fossil fuels. Running these desalination plants

with renewable energy resources like VLS-PV systems would satisfy requirement of

sustainability [2].

Local and traditional technologies are adopted in the developing regions of the world;

however these are neither cost nor labor efficient. Replacing these technologies with

exotic and state of art technology does not work properly. For the countries like

Pakistan it is essential to adopt ‘intermediate technology’ between traditional and

modern technology. VLS-PV systems may work for this purpose because they have

flexibility because of their modular size.

PV systems based on desalinized water have the potential to improve sustainability of

traditional agricultural systems in semi-arid regions. It might improve the local

community’s economic situation. The choice of proper irrigation practices and

introducing additional cash crops to earn money may be an incentive for introducing a

system of sustainable production and cash crop would itself help to improve the

economic situation in developing regions.

6.4 Job Creation

The VLS-PV systems can create a lot of jobs in Thar region. Manpower is required

for installation, operation and maintenance of these systems. There is huge mining

potential in Thar Desert but requires energy for exploration. Thousands of jobs can be

created in this region by providing this energy through VLS-PV. It will improve the

living standards of people.

51

As the demand of technical manpower will increase, it will promote the technical

education. People of these areas will have an interaction with the other world; it will

create awareness among them. It will also improve transportation facilities in the

desert areas as these areas will become economic hubs. It will also create peace and

harmony in the country.

6.5 Technology Transfer

In addition to above benefits various kinds of technologies may be transferred among

the nations. A country like Pakistan needs the various available PV technologies.

Installation of VLS-PV systems will be the initiative of technology transfer.

Knowledge of operation will also be shared which will be beneficial in future.

To promote PV systems in the world, technology and knowledge transfer are needed

for the developed to underdeveloped countries. Studies show that developing

countries have good natural conditions for VLS-PV systems. Pakistan has best hot

arid conditions for VLS-PV but the financial problems are big hindrance to these

systems.

For developed countries these deserts areas could become a huge market. Sharing

ideas in the institutes is also very vital because it will further promote research on

solar energy.

6.6 Grassland and Forestation

In order to prevent further desertification which might have a disastrous effect on the

life of people we can plant trees. Pumping water in the desired areas in the deserts

will create the grassland. Planting trees on the regular bases may help forestation.

Sustaining greening will have good aesthetic effects and will prevent further

desertification.

To obtain a good acceptance of solar electricity systems, it will be necessary to make

people aware of the advantages and the potential of solar electricity generation in

desert regions. Such awareness creation is necessary at all levels in local

communities.

52

The roles of major stakeholders such as renewable energy institutes, energy

companies, government institutions, financial institutions and educational institutes

are significant.

53

Chapter 7 Conclusions and Recommendations

7.1 Conclusions Results of this project show that VLS-PV can become a viable source of energy

generation in Pakistan in future. There is no problem of large area requirement for

VLS-PV; only problem is the availability of transmission network. We need to extend

the network especially in important areas of Baluchistan. There is also a need to

enhance the capacity of already existing grids

Thin film technology has made VLS-PV a viable and economical source of

generation. It is expected that thin film module prices will fall further in future. The

grid parity may be achieved for VLS-PV in coming years for Pakistan. VLS-PV can

become one of the options to resolve the ongoing energy crisis in our country.

Fossil fuels like Furnace Oil are not feasible for Pakistan at all. Instead of financing

too much on the Rental Power Plants and other such options we should consider VLS-

PV and other alternatives. Incentives should be provided to investors and regulations

should be made regarding alternatives. Tax free lands can be provided for specific

years for promotion of VLS-PVs

VLS-PV will have socio-economic impacts in our country. Desert and Baluchistan

areas are full of natural resources but lack of energy is hindrance in their exploration.

VLS-PV can provide this energy to boost the exploration of these natural resources. It

will improve the overall living standard of people in these areas.

7.2 Future Work Future work includes:

• Feasibility of VLS-PV for Quetta and other new sites

• Design of controllers and motors used in tracking systems of VLS-PV

• Feasibility of different storage options like fuel cells and battery storage.

54

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