Transcript Solar Energy

Layout of a silicon solar cell
Components of a PV system
 Module – consists of many cells wired together
 Support structure
 Inverter – converts DC module output to AC
power at the right voltage and frequency for
transfer to the grid
 Concentrating mirrors or lens for concentrating
PV systems
Types of PV cells
 Single-crystalline
 Multi-crystalline
 Thin-film amorphous silicon
 Thin-film compound semiconductors
 Thin-film multi-crystalline
 Nano-crystalline dye-sensitized cells
 Plastic cells
Thin-film compound
semiconductors
 Cadmium telluride (CdTe)
 Copper-indium-diselenide (CuInSe2, CIS)
 Copper-indium-gallium-diselenide (CIGS)
 Gallium arsenide (GaAs)
Best efficiencies achieved as of 2009
Technology
c-Si
m-Si
a-Si
thin-film Si
CdTe
CIGS
InP
thin-film GaAs
m-GaAs
a-Si/µc -Si
a-Si/a-SiGe/a-SiGe
thin-film GaAs/CIS
GaInP/GaAs
GaInP/GaAs/Ge
GaInP/GaInAs/Ge
Dye-sensitized
Organic
Unconcentrated Sunlight
Concentrated Sunlight
Cell
Module
Cell
Concentration Factor
Single-junction silicon semiconductor
25.0
22.9
27.6
92
20.4
15.5
9.5
16.7
8.2
Single-junction compound semiconductors
16.7
10.9
19.4
13.5
21.8
14
22.1
26.1
28.8
232
18.4
Multi-junction semiconductors
11.7
10.4
25.8
30.3
32.0
40.7
240
41.1
454
Photochemical and Organic
10.4
5.2
Trend in efficiency of PV cells and modules
Structure of the
GaInP/GaInAs/Ge
multi-junction
Cell
Factors affecting module
efficiency
 Solar irradiance – efficiency peaks at around 500
W/m2 for non-concentrating cells
 Temperature – efficiency decreases with
increasing temperature, more so for c-Si and
CIGS, less for a-Si and CdTe
 Dust – can reduce output by 3-6% in desert
areas
Module efficiency vs solar irradiance,
theoretical calculations
Module efficiency vs solar irradiance, measurements
System efficiency is the product of
 Module efficiency
 Inverter efficiency
 MPP-tracking efficiency
Inverter & MPP Efficiency, measured
MPP-tracking efficiency
100
MPP Tracking Efficiency (%)
90
80
Morning
70
Afternoon
60
50
40
30
20
10
0
0
20
40
60
Load (%)
80
100
BiPV on single-family house in Finland
BiPV on a single-family house in Maine
PV modules (attached to insulation)
on a horizontal flat roof
Source: www.powerlight.com
PV modules servings as shading louvres on
the Netherlands Energy Research Foundation building
Supplemental figure PV modules as vertical shading louvres on
the SBIC East head office building in Tokyo
PV modules providing partial shading in the atrium of
the Brundtland Centre (Denmark, left)
and Kowa Elementary School (Tokyo, right)
Source: Shinkenchiku-Sha
Source: Henrik Sorensen, Esbensen Consulting
The Netherlands
Growth in annual PV production
Annual Installation of PV (MWp-AC)
6000
Rest of World
USA
Rest of Europe
Spain
Germany
Japan
5000
4000
3000
2000
1000
0
1998
2000
2002
2004
Year
2006
2008
Growth in installed PV power
Capacity (MWp-AC)
16000
Rest of World
USA
Rest of Europe
Spain
Germany
Japan
12000
8000
4000
0
1998
2000
2002
2004
Year
2006
2008
Price of Photovoltaic Module
Price of PV modules (US$/Wp)
100
10
1
0.1
1
10
100
1000
Cumulative global PV module shipments in MWp
10000
Triple-junction a-Si on laminated roofing
PV Scenario
70
20%/yr growth in production capacity
after 2006, PR=0.8
Peak Power (GW)
150
60
50
Cost
40
100
30
20
50
Installed Peak
Power
0
2000
2005
2010
10
2015
0
2020
Cost of Electricity (cents/kWh)
200
PV Scenario
350
70
30%/yr growth in production capacity
after 2006, PR=0.8
Peak Power (GW)
300
250
60
50
Cost
40
200
30
150
20
100
50
0
2000
Installed Peak
Power
2005
2010
10
2015
0
2020
Cost of Electricity (cents/kWh)
400
Solar Module Annual Tilt
NP
Summer
Solstice
Spring
Winter
Solstice
NP
NP
-23.5°
SP
+23.5° tilt
NP
SP
SP
Fall
SP
 Modules are tilted at latitude angle to be aimed at sun on
equinoxes; at solstices, they are off by the obliquity angle
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To Sun
Zenith (up)
Zenith
Angle
To Sun
North
Pole
Solar Declination Angle
Horizontal Plane
Latitude
Angle
Equatorial Plane
Zeni
Sun’s zenith angle is measured from local
vertical
Equator
Zenith Angle of Sun
South Pole
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Optimum Solar Module Tilt
 Website calculations
PV ARRAY: SOLAR NOON TILT
DATA
Latitude = 28 Degrees North
Month
Sun
Altitude
Array
Tilt
Array
Points to:
JAN
42
48
South
FEB
51
39
South
MAR
62
28
South
APR
74
16
South
MAY
82
8
South
JUN
85
5
South
JUL
82
8
South
AUG
74
16
South
SEP
62
28
South
OCT
50
40
South
NOV
42
48
South
DEC
39
51
South
Array Tilt = 90 degrees - Sun Altitude
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