1

Sun: Energy source of the

future

Dr Adil Sarwar

Department of Electrical Engineering

Aligarh Muslim University

Layout of the Presentation 2

Need for sustainable source of energy

Solar energy: direct and indirect

Main features of terrestrial solar radiation

Solar radiation spectrum

Insolation

Solar data

Resource estimation and measurement

Overview of thermal and PV applications, solar heat collectors

3

Need for sustainable source of energy

World Energy Consumption 4

World Energy Consumption by Source, Based on Vaclav Smil estimates from Energy Transitions: History, Requirements and

Prospects together with BP Statistical Data for 1965 and subsequent

Our Dependence

on fossil fuels.

5

Adverse effects of indiscriminate

use of fossil fuels

Pollution 6

Global warming, rise in Sea Level

Oil spill, destruction

of marine life

Depletion of

Ozone Layer

Environmental Impact

7

Global distribution of coal 8

9

Coal deposit in India 10

11

Historical Incidents 12

First Oil Crisis ( October 1973) and Second Oil

Crisis(1979).

13

Chernobyl Accident: Nuclear Disaster(26 April 1986)

14

Fukushima Nuclear Disaster (11 March 2011)

15

Moving to Renewable

Sources of Energy

Renewable Sources of Energy 16

1. Wind 2. Solar 3. Tidal 4. Geothermal

Free

Inexhaustible

Availability in a large part of the world

No or Low Pollution

Low Maintenance (Especially in Solar PV-there is no

moving part)

17

Solar energy: Direct and

Indirect

Solar Radiation 18

The sun is sending us radiation over a wide range

of wavelengths at varying intensities. The electro-

magnetic solar radiation impinging on the upper

edge of the atmosphere is called extra-terrestrial

radiation. The mean integral for the complete

spectrum is 1,367 W/m² (the Solar Constant).

The complete spectrum comprises the ultraviolet

(UV), visible (Vis) and infrared (IR) wavelengths

19

20

Solar radiation is the driver for many chemical, biological and physical phenomena in the atmosphere, on the ground and in the seas.

A major effect of solar radiation reaching the earth’s surface is that it is warming it up, which is vital for our existence. 30% of the extra-terrestrial radiation solar radiation is reflected back into space but approximately 51% is absorbed by land and water and another 19% is absorbed by the clouds and atmosphere.

Earths energy budget 21

Solar Radiation attenuation 22

The attenuation of solar radiation passing through our atmosphere is due to the following processes:

ultraviolet range Scattering by molecules and aerosol particles and absorption by Ozone, Sulphur Dioxide, Nitrogen Dioxide and trace gases.

visible range Scattering by molecules and aerosol particles, little absorption by aerosol particles, Ozone and other trace gases.

infrared range Absorption by water vapour and aerosol particles but little scattering.

Advantages of analyzing solar

radiation 23

Nowadays, measuring solar radiation is extremely

important in many different fields of application,

such as climatology, meteorology, hydrology,

pollution forecasting, solar energy, agriculture and

material testing.

Solar Spectra 24

Air Mass(AM) 25

The air mass coefficient defines the direct optical path length through the Earth's atmosphere, expressed as a ratio relative to the path length vertically upwards, i.e. at the zenith.

The air mass coefficient can be used to help characterize the solar spectrum after solar radiation has traveled through the atmosphere.

The air mass coefficient is commonly used to characterize the performance of solar cells under standardized conditions, and is often referred to using the syntax "AM" followed by a number. "AM1.5" is almost universal when characterizing terrestrial power-generating panels

Contd.. 26

For a path length “L” through the atmosphere, for solar radiation incident at angle “z” relative to the normal to the Earth's surface, the air mass coefficient is

AM=L/Lo=1/sin z,

where Lo is the zenith path length (i.e. normal to the Earth's surface) at sea level and z is the zenith angle in degrees.

The air mass number is thus dependent on the Sun's elevation path through the sky and therefore varies with time of day and with the passing seasons of the year, and with the latitude of the observer.

Terms associated with solar spectrum

27

AM0

The spectrum outside the atmosphere, approximated

by the 5,800 K black body, is referred to as "AM0",

meaning "zero atmospheres". Solar cells used for

space power applications, like those on communication

satellites are generally characterized using AM0.

28

AM1

The spectrum after travelling through the atmosphere

to sea level with the sun directly overhead is referred

to, by definition, as "AM1". This means "one

atmosphere". AM1 (z=0°) to AM1.1 (z=25°) is a

useful range for estimating performance of solar cells

in equatorial and tropical regions.

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AM1.5

Solar panels do not generally operate under exactly one atmosphere's thickness: if the sun is at an angle to the Earth's surface the effective thickness will be greater.

Many of the world's major population centres, and hence solar installations and industry, across Europe, China, Japan, the United States of America and elsewhere (including northern India, southern Africa and Australia) lie in temperate latitudes. An AM number representing the spectrum at mid-latitudes is therefore much more common.

"AM1.5", 1.5 atmosphere thickness, corresponds to a solar zenith angle of z=48.2°. While the summertime AM number for mid-latitudes during the middle parts of the day is less than 1.5, higher figures apply in the morning and evening and at other times of the year. Therefore, AM1.5 is useful to represent the overall yearly average for mid-latitudes.

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Air Mass definition

Solar Energy Distribution 31

Solar Irradiance vs Solar Insolation 32

Solar Irradiance (power density) refers to the rate

of energy received by a surface per unit area. It is

the flux of solar energy. Unit is W/m2.

Solar Insolation (Energy density) refers to the

amount of energy received by a surface over a

given period of time. It is the integrated irradiance

over a time. Unit is WHr/m2.

Solar Constant 33

The average amount of solar radiation received by

the Earth's atmosphere,per unit area, when the Earth

is at its mean distance from the Sun. It isequal to 13

67 watts per square meter. Solar radiation varies w

ith theEarth's distance from the Sun and with the ap

pearance or decay ofsunspots.

34

Solar Energy 35

Solar Thermal

Solar Photovoltaic

Grid

Application Street Lighting and Traffic

Agriculture Residential and health

Transportation

Solar PV

Application

Space

Application

37

Solar Potential in India

38

Solar Potential (GWp) 39

38.44

8.65 13.76

11.2 18.27

2.05 0.88

35.77 4.56

33.84

111.05

18.18 24.7

6.11 61.66

64.32 10.63

5.86

9.09

7.29

25.78 2.81

142.31

4.94

17.67 20.41

2.08

22.83 16.8

6.26 0.79

Andhra PradeshArunachal PradeshAssamBiharChhattisgarhDelhiGoaGujratHaryanaHimachal PradeshJammu & KashmirJharkhandKarnatakaKerelaMadhya PradeshMaharashtraManipurMeghalayaMizoramNagalandOrissaPunjabRajasthanSikkimTamil NaduTelanganaTripuraUttar PradeshUttarakhandWest BengalUT

Uttar Pradesh

22.83 GWp

Initiatives by Indian Government 40

Ministry of new and renewable energy under

government of India is dedicated to planning,

development, research and implementation in the

area of renewable energy

National Solar Mission is an ambitious project to

generate 100 GW of electricity from solar energy.

70% of it through Solar PV alone both by grid and

off grid applications by 2021.

Solar PV-Indian Scenario 41

Charanka Solar Park ( Gujrat) 42

Recently Madhya Pradesh Cabinet has approved construction of

750MW solar PV plant in Rewa

Global PV market 43

0

5000

10000

15000

20000

25000

2010 2011 2012 2013 2014 2015 2016

MW

Year

CHINA

US

JAPAN

INDIA

India is

Catching up.

Global Solar PV installed 44

Observation by Global data 45

The global cumulative installed capacity for solar

Photovoltaic (PV) power will rise from 178 Gigawatts

(GW) in 2014 to an estimated 223.2 GW in 2015

China will remain the world’s largest market for annual

solar PV installations in 2015, adding around 17.6 GW

this year.

The US will follow with almost 8.2 GW of additions.

India will witness strong demand in its solar PV market

thanks to growing policy and political support.

46

Solar PV- Challenges

1. Efficiency

Solar Cell Technology Options 47

Crystalline Silicon solar cells

- Single, Multi, Ribbon

Thin Film solar cells

- Silicon, a-Si, m-Si, CdTe,

CIGS

Solar Cell Technology Options 48

Concentrating solar cells

- Si, GaAs

Dye, Organic, Nano-materials & other emerging

solar cells

Best Research Cell Efficiency 49

50

Solar PV- Challenges

2. Cost

51

Swanson Effect-Price of Solar PV

Solar PV- Indian Market 52

0

10

20

30

40

50

60

Rs

Per

Wa

tt

53

Par

amet

ers

Data-Old

54

Solar PV- Challenges

3. Intermittent nature

I-V and P-V characteristics of a PV cell 55

0 5 10 15 20 250

5

10

15

20

25

Voltage (Volts)

Po

we

r (W

atts)

I-V Characteristic

P-V Characteristic

Maximum Power Point

P-V characteristics (Uniformly Shaded

Panels) 56

0 5 10 15 20 250

10

20

30

40

50

60

70

Voltage(volts)

Po

wer(w

att

s)

1000W/m

2,30C

1000W/m2,40C

1000W/m2,50C

800W/m2,50C

800W/m2,40C

800W/m2,30C

400W/m2,30C

400W/m2,50C

800W/m2,40C

Insolation

Increasing

Temperature

Increasing MPP

Partial Shading 57

Uneven illumination of PV

panels connected in series

and parallel.

1. Cloud

2. Hindrance like Building,

Tree shade etc.

3. Dust accumulation.

Solar PV panels are

connected in series and

parallel to enhance the power

handling capability

P-V characteristics (Partial Shading) 58

0 2 4 6 8 10 12 140

5

10

15

20

25

30

Voltage (Volts)

Po

we

r(W

atts)

1000,200

1000, 350

1000,400

1000, 600

1000,300

Insolation level on two

Panels in Watts/m2

Max

imum

Pow

er Poin

ts

Local Maxima

Global Maxima

With Complex shading pattern no. of Peaks increases

59

0 5 10 15 20 250

10

20

30

40

50

60

70

Voltage (volts)

Po

we

r (W

)

Ir1=1000,Ir2=800,Ir3=200

Ir1=1000,Ir2=800,Ir3=400

Ir1=1000,Ir2=800,Ir3=600

Three Local Maxima

Maximum Power Point Trackers 60

Mechanical Tracker: 1. Single Axis Tracking

2. Dual Axis Tracking

Mechanical movement of panel to keep it facing the

sun.

Electronic Tracker: A DC/DC converter with

MPPT enabled control algorithms for switching

Stand alone application

PV Panel

Hybrid output Converter for Micro

grid Applications 62

AC

Lo

ad

S1 S3

S4 S2

DC-DC Buck

Converter with

MPPT

PV

Arr

ay

DC

Lo

ad

Digital Signal

Controller

From load

and PV

L

C

Maximum Power Point Tracking 63

Conventional MPPT algorithms

MPPT

technique

Convergence

speed

Implementation

complexity

Periodic

tuning

Sensed

parameters

Perturb &

observe

Varies Low No Voltage

Incremental

conductance

Varies

Medium No Voltage,

current

Fractional Voc Medium Low Yes Voltage

Fractional Isc Medium Medium Yes Current

MPPT Algorithms for Partial Shading

Methods Advantages Disadvantages

System

characteristic curve

method

Good tracking speed

Requirement of open or short

circuits can cause power loss

or safety concerns, method

fails in some cases

Two stage

searching method

Its implementation is easy and

it can be integrated into

traditional PGS

It can fail to track GMPP in

some cases

Direct method

Based on a solid mathematical

foundation and good tracking

speed

Cannot be directly integrated

into traditional PGS

Fibonacci methods Based on a solid mathematical

foundation

Fail to track GMPP in some

cases and cannot be directly

integrated into traditional

PGS

Fuzzy logic control

No need of precise

mathematical model, it is very

suitable for use in non-linear,

time-varying and systems

without complete models

high hardware cost

MPPT Algorithms for Partial Shading

Genetic Algorithm Can optimize parameters of

other algorithms such as FLC

Its implementation is complex

and difficult to achieve using

low cost microcontroller

Current sweeping

method Fast tracking speed

Requires periodical tracking of

the MPP

Ant colony

optimization

Fast convergence and

convergence independent of the

initial condition

Implementation is difficult

Differential

Evolution

Fast convergence and

convergence independent of the

initial condition, easy to use

Some parameters may not

guarantee optimal solution

Particle swarm

optimization

Simpler structure than other EA

techniques

Optimization performance

depends on parameter

selection

Chaos search

method

Improved search efficiency,

precision, and system robustness High complexity

Electrical PV array

Reconfiguration

Compensate the power losses

caused by PSC

Expensive and the controller

design is also complex, fail to

track GMPP in some shading

patterns

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Solar PV- Challenges

4. Integration with Grid

Grid application Many Issues with Grid integration.

1. Poor THD

2. Synchronization

3. Islanding Problem

Hot areas of Research

Solar PV for Happy and Safe Future 69

With a lot of investment in solar PV area by the

world governments, it is going to be one of the

major player in power industry.

As People are becoming more Conscious and

Concerned about environmental degradation, they

are turning towards neat and cost effective solution

to power requirement. In Germany, one can find

almost all the commercial and residential buildings

with solar PV rooftops.

THANK YOU

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