Semiconductors for Efficient Energy Solutions...Arnab Bhattacharya VCSELs overview Indo-Dutch...

Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 1

Semiconductors for Efficient Energy Solutions

B. M. Arora

Dept. of Electrical Engineering

IIT Bombay Powai , Mumbai 400 076

Email: [email protected]

NC2E-2014 Pune Univ , 21 Feb 2014


OUTLINE OF TALK

i) PHOTOVOLTAICS ( PV)

Semiconductors Based Electricity Generation

Silicon Solar Cells

Thin Film Solar Cells I) Amorphous Silicon , ii) Copper Indium Gallium Diselenide , iii) Cadmium Telluride

iv) Organic Semiconductors, v) Dye –Sensitized

Heterojunction Solar Cells

Tandem Solar Cells

ii) SOLID STATE LIGHTING (SSL)

Semiconductors Based Light Sources

Blue LEDs with Green and Red Phosphors

Blue Green and Red Light Emitting Diodes

Organics (OLEDs)

Indian Power Sector (30th September, 2013)

Thermal

1,55,969 MW

Hydro

39,788 MW

Nuclear

4,780 MW

Renewable

28,185 MW

68.19%

17.40%

2.09%

12.32%

Power Installed Capacity = 2,28,722 MW

Thermal

Hydro

Nuclear

Renwable

3

Renewable Power Capacity (31st October, 2013)

(Grid Connected)

Wind

19,934 MW

Small Hydro

3,747

MW

Bio

3,776

MW

Solar

2,080

MW

Total

29,537

MW

4

67.4%

12.7%

12.8%

7.1%

Wind

Small Hydro

Bio

Solar

(927 MW Off Grid/Captive Power - mostly Waste to Energy,

Biomass/Cogeneration, SPV


ENERGY USAGE IN INDIA

About 15 - 20 % of Electricity is used for Lighting

6

Mission Road Map

Application Segment Target for Phase I

(2010-13)

Cumulative Target for Phase 2

(2013-17)

Cumulative Target for Phase 3

(2017-22)

Grid solar power (large plants, roof top & distribution grid plants)

1,100 MW

4,000 - 10,000 MW

20,000 MW

Off-grid solar applications

200 MW

1,000 MW

2,000 MW

Solar Thermal Collectors (SWHs, solar cooking/cooling, Industrial process heat applications etc.)

7 million sq. meters

15 million sq. meters

20 million sq meters

Solar Lighting System 5 million 10 million 20 million

6

Potential of Solar Energy in India

• The daily average solar energy incident varies from 4 - 7 kWh

per square meter.

• The potential of power generation is 30 – 50 MW per square

kilometer of land area depending upon the technology and

geographical location.

• It is possible to set up solar power generation capacity of over

1,00,000 MW in India.

• Potential for solar power is dependent on future developments

that might make solar technology cost-competitive for grid-

interactive power generation applications.

7


ESTIMATE OF ENERGY CONSUMPTION

Present World ~ 15 TW

Consumption

Source : EPIA (EUROPEAN PV Industry Assocn ) 2006


Kerosene Lantern, Solar Lantern, Solar Hut

Kerosene Lantern gives about 30 lumens , consumes about

1-2 litre of Kerosene per week.

Off-Grid Solar Power in Rural India

A 10 Wp PV module can supply one 7W

CFL for 4 hours


c-Si 5 kW Installation at Auroville

SPV Power Plant at Goshen Drass Kargil

(40 kWp)

11

5 MWp SPV Plant at Khimsar, Rajasthan

12


Elemental Semiconductors : C,Si,Ge Compound Semiconductors

Semiconductors for Solar Cells and LEDs

III IV V VI

GaAs

CdTe

GaN

InGaP

CuInSe

InGaN

CuInGaSe

CuZnSnSe

AlGaInP

INORGANIC Materials

ORGANIC Materials : A Whole New World


Solar Cell Generations

Perovskite Solar Cells


Commercial Solar Cells

S Guha , Physics News 2011


The Energy We Receive From Sun

Earth receives about 100 mW /cm2 or 1kW /m2

from sun.

Mission Target ~ 20GW

Consider 15 % utilization efficiency + Installation

Area for harnessing 20 GW ~ 300 km2

About 75,000 acres

Amount of Silicon required include Losses ~ 10Kgm/KW

20 GW requires ~ 200 X 106 Kgm


Mono and Multi-crystalline Silicon

Monocrystalline Silicon

INGOT

Silicon Wafers

Cell

Multicrystalline Silicon

Wafer Cell

Brick


Mono and Multi Crystalline Silicon Solar Cell

Single Crystal / Multi-Crystalline Si

Loss High Temp High Temp

Process Steps

S Guha Talk IIT Bombay Dec 2011

p-Si (~ 200 μm)

Texturing


Some Typical Solar Cells

c-Si Solar Cells

Flexible


Standard Solar Spectra


Illuminated Solar Cell I-V Chracteristics

FF= [VMP . IMP] / [VOC . ISC] , η = Pmax / Pin

Quantities of Interest :

VOC, ISC, VMP, IMP, Pmax, Fill Factor(FF), Efficiency( η),

Series Resistance Rs,Shunt Resistance Rsh

Pin requires measurement of input optical power


Solar Cell Parameters

23

Fundamental losses – Single/ Tandem

Ideal cell Eff, 100%

28% escapes as hν<Eg (1.124eV)

can be reduced by tandem cells

25% loss as hot-carrier hν>>Eg

can be reduced by tandem cells

Radiative & Auger limits the usable output to only 29.8%

Fundamental factors limiting Efficiency

72.2%

47.0%

29.8% 29.8%

100.0%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Ideal

Tra

nspare

nt

Hot

carr

ier

Intr

insic

loss

Usable

Eff

, %

Unavoidable losses for single gap S/C

Optical Loss

Optical/Electrical Loss

Carrier Loss


Examples of Silicon Solar Cell Efficiency

Characterisctics of a common silicon solar cell under standard illumination( 100 mW /cm2 ) in commercial solar panel

VOC = 600 mV

I SC = 35 mA / cm2

FF = 0.75

η = (VOC . I SC .FF)/ Pin = 15.75%

Highest efficiency laboratory silicon cells * ( Area ~ 4 cm2 )

* * Zhao et al , Prog Photovolt Res & Appl 7, 471 (1999)


Prof Martin Green

• Univ of New South Wales , Syddney , Australia

Pioneering work in Silicon Solar Cells

PERT : Passivated Emitter Rear Totally Diffused ; PERL : Passivated Emitter Rear Locally Diffused


Additional Losses in Real Life Cells

• Theoretically achievable efficiency is 29.8 % . Where does a

16.2 % cell lose the rest ?

Optical Losses , Carrier Losses


Major steps for higher efficiency

Minimize back reflection , Texturing & ARC

Minimize bulk- recmbination .Highest lifetime material

Minimize junction recombination ( heavily doped-Auger recombination important)-to minimize Auger, use a moderately doped emitter layer.

To minimize front surface recomb., use oxide passivation of front surface

To minimize back surface recomb. , provide a field assist to drive holes away


NREL REPORT BEST CELLS


A two junction Solar cell


Record Laboratory Solar Cell Efficiencies

Highest Efficiencies Achieved in Small area Cells in Labs

Mono-Si 25 % ( UNSW, 1999)

Multi – Si 20.4 ( FhG-ISE ,2004)

a-Si:H

a-Si:H – c-Si (HIT) 24.7 ( Sanyo, 2013)

CdTe 18.7 ( First Solar, 2013)

CIGS 20.4% ( EMPA, 2013)

CZTSSe 11.1 % ( IBM, 2013)

Organic

Triple –Jn ( one sun) 37.7 % ( Sharp, 2013)

Triple – Jn ( x 942) 44% (

16.3 United Solar,2011) (Triple Jn )

11.1% ( 2012)

Solar Jn )


Price of Module

Factors driving Down Prices

1) Poly-silicon price fell from $ 400/Kg in 2007 to $ 25 /Kg in 2011

2) Increasing Cell efficiency

3) Improvements in Manufacturing Technology

4) Economies of scale

5) Intense Competition

Price Rise caused by

Silicon shortage

Rough Prices in Rupees

Multi-silicon : Rs 35 per Wp in large quantity (MW)

: Installed system ~ Rs 80 per Wp

Rs 60 per Wp ( small numbers)


Cost of Solar Electricity

S Guha, Physics News 2011


National Centre for PV Research & Education (NCPRE) IIT Bombay

• Mandate:

i) Research and Development :

a) High efficiency silicon solar cells (20% efficiency)

b) Novel Materials

c) Power Control Electronic systems ( ~ 5 kW)

d) Characterization and Modeling ( Solar Modules)

e) Indian National Users Programme ( INUP)

f) Industry Affiliates

ii) Education :

a) Development of PV courses at IIT Bombay

b) Outreach : 1) Short term courses dealing with solar cells,

power control electronics etc

2) Educational experimental kits for learning

of Solar cells, modules,

NCPRE requested to do this by

MNRE’s ”High Level Task Force

for Solar PV”

Survey done jointly with

Solar Energy Centre (SEC)

Hot & Dry Zone

No. of Sites 1

No. of Modules 7

Hot & Humid

No. of Sites 15

No. of Modules 27 Temperate Zone

No. of Sites 1

No. of Modules 2

Composite Zone

No. of Sites 2

No. of Modules 16

Cold & Dry Zone

No. of Sites 1

No. of Modules 3

All 5 Climatic Zones

of India covered

15 year Old PV Module

working fine

Discoloration & Cell

Cracks (blue lines)

Discoloration &

Delamination

Corrosion & Delamination (Left) and corresponding

IR Image showing Hot Spot (Right)

White Powder from

degraded Back sheet Corrosion, Burn Marks

and Discoloration

Shattered Glass

Histogram of calculated Pmax

degradation

Degradation in Pmax for c-Si IV parameter degradation-Mono c-Si

IV parameter degradation-Mono c-Si Pmax degradation in different climatic zones

Data Analysis is in

Progress

IV Curves

STC 1:α,β keeping Rs=0,k=0

STC 2:cosidering all 4 parameters

Corrections as per IEC 60891 procedure 1: Graphs generated using variable

radiance data from IITB modules.

From the graphs we can infer that the

error in translation is within 10 % for

STC 1 method.

Survey Report is under preparation

and will be submitted to High Level

Task Force by end of August.

SPIRE Solar Simulator

• 300 nm – 1100 nm Spectrum considering

trend towards High Efficiency Modules

• Class A+A+A+

• 2 m x 1.3 m Modules

Environmental Chamber

• Temperature Cycling Test

• Damp Heat Test

• Humidity Freeze Test

• PID Test

PV Module Monitoring Station

• DAYSTAR Multi-IV Tracer (16 Channels,

3200W)

• 5 Different PV Module Technologies

• Continuous Monitoring of Performance

Other Equipments:

• Electroluminescence Camera

• Infra-Red Camera

• High Voltage Tester

Purchase of Solar Simulator, Environmental Chamber, EL Camera, IR Camera & High Voltage

Tester is in the process


SOLID STATE LIGHTING (SSL)

Semiconductors Based Light Sources

Blue LEDs with Green and Red Phosphors

Blue Green and Red Light Emitting Diodes

Organics (OLEDs)


Lighting with Electricity

Low Pressure Sodium Vapor Lamp

High Pressure Sodium Vapor Lamp


Two Approaches for Producing White Light

White Light can be produced

in different ways

LEDs – Red + Green + Blue LED (RGB)

Blue LED + Red Phospher + Green Phosphor LED (PC)

U S Dept of Energy April 2013


O

Large Savings in Electricity , to the tune of 10,000 MW or more,

are expected by replacing inefficient lamps with LED lamps

44

White GaN-based LEDs in outdoor lighting

• Pedestrian bridge across Rhine river harbour, Duisburg, Germany

Progress in LED brightness

• Nitrides and organic materials are overtaking conventional III-V’s in brightness and opening new wavelengths

GaAsP

red

GaP:Zn,O

red

GaAsP:N

red/yellow

AlGaAs/GaAs

red

AlGaInP/GaAs

red/orange

AlGaInP/GaP

red/orange

AlGaInP/GaP

red/orange

OLED green

31lm/W

InGaN green

25lm/W InGaN blue

25lm/W

>100 lm/W

SiC

blue

GaP:N

green

PPV

1960 1970 1980 1990 2000

Alq3

100

1

10

0.1

Fluorescent

Lamp

Incandescent

Lamp

Edison’s

1st bulb

Perf

orm

ance (

lum

ens/w

att)

Year


Efficiency & Efficacy of Various Light Sources

• Type of Light Source Efficiency Efficacy

(%) (lm/W)

• Incandescent light bulb 5 15

• Long fluorescent tube 25 80

• Compact fluorescent lamp (CFL) 20 60

• High-power white LEDs 30 100

• Low-power white LEDs 50 150

• Sodium lamp (high-pressure) 45 130


Advantages of LEDs over CFL

LEDs are Environmentally Friendly Compared to CFL


Solid State Lighting

Long Life

Incandescent Lamp ~ 1000hrs

CFL ~ 8000-10000 hrs

Linear Fluorescent Lamp ~ 30000 hrs

LED ~ 30000-50000+ hrs

Prices

Table U S Dept of Energy April 2013


Eye Sensitivity

614

↓

548

↓

456

↓

i) Lighting Requires White

Light

ii) White light :

Red + Green + Blue

iii) White Light can be

Cool White Or Warm White

depending on the amount

of Red component

Quality of LED Lighting


Quality of Light and Light Sources

• Colour Rendering Index ( CRI) : depends on spectral content

of lamp and reflectance of object ( 8 StandardTest Colours)

CRI is a measure of “ ability of Light Source to render color”

CRI of 90 or above indicates excellent color rendering.

CRI of 80 or above recommended for interior lighting.

Warm white LEDs have CRI of 80 and above.

• Correlated Colour Temperature ( CCT):

Warm White (Yellowish) Sources have Colour Temp 2700-

3000K and are used for Interior Lighting

Neutral white sources have colour temperature 3500-4000K

Cool white ( Bluish) sources have higher colour temp.


Price Comparison Of Sources



Prices of LEDs



Red Green Phosphors Based GaN White LED

Red Phosphor

Green Phosphor

White Light

State of the art in 2009 : Input Electrical Power : 3.2 V x 0.7 A ~ 2.2 W

Total Lumens : 129 lm , ~ 59 lm/W

Blue LED Efficiency : 0.73/ 2.2 = 0.33

Power Conversion Efficiency : 0.403/0.73 = 0.55

Spectral Efficiency : = 0.78

Gen Blue Power : 0.73 W

Output Blue Power : 0.036W

Output Green Power : 0.104 W

Output Red Power : 0.263 W

Total Light Power Out : 0.403 W

Jeffrey Y. Tsao et al Proceedings of the IEEE | Vol. 98, No. 7, July 2010

Δλ (440) = 24 nm, Δλ (538) = 75 nm, Δλ (615) = 95 nm,

Overall Efficiency : 14 %

Possibilities of Much Higher

Efficiency (> 50% ) and

Efficacy ( 400 lm /W) outlined.


OUTLOOK

Semiconductors offer tremendous opportunities

for devising efficient means of generating

of electricity using Solar Energy . There are

equally great opportunities for efficient

utilization of energy, particularly for Lighting.

Much greater effort is needed to harness these

opportunities


Thank you !

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Semiconductors for Efficient Energy Solutions...Arnab Bhattacharya VCSELs overview Indo-Dutch...

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