Semiconductors for Efficient Energy Solutions...Arnab Bhattacharya VCSELs overview Indo-Dutch...
Transcript of 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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 2
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
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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.
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Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 8
ESTIMATE OF ENERGY CONSUMPTION
Present World ~ 15 TW
Consumption
Source : EPIA (EUROPEAN PV Industry Assocn ) 2006
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 9
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
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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
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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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 14
Solar Cell Generations
Perovskite Solar Cells
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Commercial Solar Cells
S Guha , Physics News 2011
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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
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Mono and Multi-crystalline Silicon
Monocrystalline Silicon
INGOT
Silicon Wafers
Cell
Multicrystalline Silicon
Wafer Cell
Brick
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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
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Some Typical Solar Cells
c-Si Solar Cells
Flexible
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Standard Solar Spectra
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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
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Solar Cell Parameters
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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
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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)
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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
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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
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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
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NREL REPORT BEST CELLS
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A two junction Solar cell
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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 )
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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)
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Cost of Solar Electricity
S Guha, Physics News 2011
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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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 40
SOLID STATE LIGHTING (SSL)
Semiconductors Based Light Sources
Blue LEDs with Green and Red Phosphors
Blue Green and Red Light Emitting Diodes
Organics (OLEDs)
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Lighting with Electricity
Low Pressure Sodium Vapor Lamp
High Pressure Sodium Vapor Lamp
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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
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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
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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
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Advantages of LEDs over CFL
LEDs are Environmentally Friendly Compared to CFL
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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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 49
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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 50
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.
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Price Comparison Of Sources
U S Dept of Energy April 2013
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 52
Prices of LEDs
U S Dept of Energy April 2013
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 53
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.
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 54
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
Arnab Bhattacharya VCSELs overview Indo-Dutch Workshop 14.1.2003 55
Thank you !