Solar Cells
shoomoosh
class01SolarCells2020-08Overviewofsolarcells1.pptxAn overview of solar cells (1)
Prof. Richard R. King
Solar Cells
EEE 565
Arizona State University
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2
Direct conversion of sunlight into electricity via the photovoltaic effect
Photovoltaic effect first discovered by Bequerel (1839), Se/Au solar cell (C. Fritts, 1883)
Modern junction solar cell (R. Ohl, 1946)
Silicon junction formation allowed formation of first practical devices, at Bell Labs (1954)
Overview of photovoltaics (PV)
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Big Picture
Fossil fuels are contributing to global climate change at alarming rate
Further, dependence on imported fuels has a high toll in terms of political stability and national security
Climate Change –
Temperature Anomaly by Year
1000 years of Earth temperature history…
and 100 years of projection
Rosina Bierbaum,
Univ. of Michigan
Intergovernmental Panel
on Climate Change (IPCC)
DOE goal of 0.02-0.03 $/kWhr accounts for costs due to intermittency of solar resource
Makes PV electricity lowest cost power option, in the absence of subsidies
LCOE vs. Eff.
Various life spans, non-module costs
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The solar resource
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Title
Acknowledgements
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Solar energy is a unique source of energy:
Large resource and renewable
Environmentally benign
Distributed generation
Over 2% of global electricity is now provided by solar cells
What technical and societal problems will have to be solved to reach 50% PV electricity?
How about 100% ?
Solar electricity opportunity
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Solar intensity:
AM0 (space) solar intensity = 0.13661 W/cm2
AM1.5G (terrestrial, global) = 0.100 W/cm2
Solar spectrum
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Solar spectrum and
photon utilization efficiency
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The solar resource
Extraterrestrial intensity of sunlight at distance of Earth’s orbit =
1366.1 W/m2 = 0.13661 W/cm2
Average radius of Earth = 6371 km
Area of Earth’s disk = π r2 = 1.275 x 1014 m2
Power of sunlight incident on Earth outside atmosphere =
1.74 x 1017 W = 174,000 TW
Power of sunlight arriving at Earth’s surface (approx. average) =
1.01 x 1017 W = 101,000 TW
(surface / extraterrestrial ≈ 58%)
Energy of sunlight incident each day on Earth outside atmosphere =
1.5 x 1022 J = 15,000 EJ = 4,180,000 TWhr
Energy of sunlight arriving each day at Earth’s surface (approx. average) =
8.73 x 1021 J = 8,730 EJ = 2,420,000 TWhr
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use inspired · transdisciplinary · intellectual fusion · social embeddedness
Solar energy distribution in the US
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Solar resource in the U.S.
over course of year
5
6
8
7
4
3
5
Direct normal spectrum received by tracking concentrator
Winter solstice
Summer solstice
Average over year
Ref.: http://rredc.nrel.gov/
solar/old_data/nsrdb/
redbook/atlas/
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Solar resource in the U.S.
for 3 collector types
5
6
8
7
6
5
Direct normal spectrum received by tracking concentrator has roughly the same kWh/(m2 day) as global spectrum received by fixed flat plate collector
Tracking flat plate has more energy per unit area per day
Ref.: http://rredc.nrel.gov/
solar/old_data/nsrdb/
redbook/atlas/
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IPCC (2001) scenarios
to 2100
IPCC (2001) scenarios
to 2100
0.000.010.020.030.040.050.060.070.080.090.1015%20%25%30%35%40%Levelized Cost of Energy (LCOE) ($/kWhr)Module Efficiency (%) 30 year life, 150 $/m2 non-module costs 30 year life, 80 $/m2 non-module costs 50 year life, 150 $/m2 non-module costs 50 year life, 80 $/m2 non-module costs
0
100
200
300
400
500
600
700
0
0.5
1
1.5
2
2.5
3
3.5
4
Photon Energy (eV)
Intensity per Unit Photon Energy
(W/m
2 .
eV)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Photon utilization efficiency
.
AM1.5D, ASTM G173-03, 1000 W/m2
Utilization efficiency of photon energy
1-junction cell
3-junction cell
6-junction cell
