Transcript Template for e7 Presentations

e8 / PPA Solar PV Design Implementation O&M
Marshall Islands March 31-April 11, 2008
1. Solar Photovoltaic Theory
1-1. Basic principles of PV
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1.Basic principle of PV
• Contents
1-1. Basic principles of PV
1-1-1. Mechanism of generation
1-1-2. Various type of PV cell
1-1-3. Installation example
1-1-4. Basic characteristic
1-1-5. Case sturdy
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• Mechanism of generation
The solar cell is composed of a P-type semiconductor and an N-type
semiconductor. Solar light hitting the cell produces two types of electrons,
negatively and positively charged electrons in the semiconductors.
Negatively charged (-) electrons gather around the N-type semiconductor
while positively charged (+) electrons gather around the P-type
semiconductor. When you connect loads such as a light bulb, electric
current flows between the two electrodes.
Electrode
Reflect-Proof Film
Solar Energy
N-Type Semiconductor
P-Type Semiconductor
Load
Electrode
Electric Current
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-1. Mechanism of generation
Photo Voltaic cell
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-1. Mechanism of generation
• Direction of current inside PV cell
• Inside current of PV cell looks like
“Reverse direction.” Why?
P
?
• By Solar Energy, current is pumped
up from N-pole to P-pole.
• In generation, current appears reverse.
It is the same as for battery.
N
P
Current appears
to be in the
reverse direction ?
Looks like
reverse
N
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• Voltage and Current of PV cell ( I-V Curve )
P
A
(A)
N
Short Circuit
•Voltage on normal operation point
0.5V (in case of Silicon PV)
•Current depend on
- Intensity of insolation
- Size of cell
High insolation
Current(I)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-1. Mechanism of generation
Normal operation point
(Maximum Power point)
P
Low insolation
V
IxV=W
N
(V)
Voltage(V)
about 0.5V
(Silicon)
Open Circuit
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• Typical I-V Curve
(A)
Depend on cell-size
5.55A
Depend on
Solar insolation
4.95A
Depend on
type of cell or
cell-material
( Si = 0.5V )
Current(I)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-1. Mechanism of generation
(V)
Voltage(V)
0.49 V 0.62 V
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Marshall Islands March 31-April 11, 2008
1-1-2. Various type of PV cell
• Types and Conversion Efficiency of Solar Cell
Conversion Efficiency
of Module
Single crystal
10 - 17%
Poly crystalline
10 - 13%
Crystalline
Silicon
Semiconductor
e8 / PPA Solar PV Design Implementation O&M
Non-crystalline
Solar
Cell
Compound
Semiconductor
Organic
Semiconductor
Amorphous
Gallium Arsenide (GaAs)
7 - 10%
18 - 30%
Dye-sensitized Type
7 - 8%
Organic Thin Layer Type
2 - 3%
Electric Energy Output
x 100%
Conversion Efficiency =
Energy of Insolation on cell
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e8 / PPA Solar PV Design Implementation O&M
1-1-2. Various type of PV cell
• Crystal cell (Single crystal and Poly crystalline Silicon)
Single crystal
Formed by melting high purity
silicon like as Integrated Circuit
Poly crystalline
For mass production, cell is sliced
from roughly crystallized ingot.
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e8 / PPA Solar PV Design Implementation O&M
1-1-2. Various type of PV cell
• Surface of PV cell
Example of Poly Crystalline PV
• Aluminum Electrode
(Silver colored wire)
• To avoid shading,
electrode is very fine.
Anti reflection film
(Blue colored film)
Front Surface
(N-Type side)
• Back surface is Ptype.
• All back surface is
aluminum electrode
with full reflection.
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-2. Various type of PV cell
• PV Module (Single crystal, Poly crystalline Silicon)
Single crystal
Poly crystalline
128W
120W
(26.5V ,
4.8A)
(25.7V ,
4.7A)
1200mm
1200mm
（3.93ft）
(3.93ft)
800mm （2.62ft）
Efficiency is higher
Same size
800mm (2.62ft)
Efficiency is lower
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-2. Various type of PV cell
• Hierarchy of PV
Cell
Volt
Ampere
Watt
Size
0.5V
5-6A
2-3W
about 10cm
5-6A
100-200W about 1m
Module 20-30V
Array
200-300V 50A-200A 10-50kW
about 30m
Array
10 - 50 kW
Module,Panel
100 - 200 W
Cell
2–3W
6x9=54 (cells)
100-300 (modules)
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• Roughly size of PV Power Station.
How much PV can we install in this conference room?
1 kw PV need 10
m2
Please
remember
(108 feet2)
20m(66feet)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-2. Various type of PV cell
Conference
Room
(We are now)
Our room has about 200 m2
(2,178 feet2)
We can install about
20 kW PV in this room
10m(33feet)
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e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Roof top of residence ( Grid connected )
Owner can sell excess
power to power utility.
Most popular installation
style in Japan.
(Almost 85% PV in Japan )
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e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Roof top of school ,community-center building.
(For education and emergency power)
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e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Distant and independent power supply ( Off grid )
Advertising sign beside highway
Relay station on top of mountain
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1-1-3. Installation example
• Mountain lodge ( Off grid )
e8 / PPA Solar PV Design Implementation O&M
Inverter and controller
1.2kW system
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e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Stationary power station (Grid connected )
e8 & PPA project in Tuvalu
30kW array
Site:
Installation:
Capacity:
Purpose:
10kW array
Funafuti Tuvalu
Feb. in 2008
40kW
Grid connected power supply for fuel conservation
and CO2 reduction.
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Stationary power station (Off grid or mini grid )
Site:
Mongolia
Installation: May & June in 1999
Purpose:
For lighting, refrigerator
and outlet in a hospital.
Solar cell capacity:
3.4kW
Wind Power capacity: 1.8kW
Inverter capacity:
5kVA
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-3. Installation example
• Solar Home System (SHS)
Solar array
Solar array
Solar array
Controller
Light
Solar array
Storage battery
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Marshall Islands March 31-April 11, 2008
1-1-4. Basic Characteristic
• I / V curve and P-Max control
A
P
V
(A)
N
Ipmax
Current(I)
e8 / PPA Solar PV Design Implementation O&M
P1
I/V curve
• To obtain maximum power, current
control (or voltage control) is very
important.
• “Power conditioner” (mentioned
later) will adjusts to be most suitable
PMAX voltage and current automatically.
P- Max control
Power curve
IxV=W
P2
(V)
Voltage(V)
Vpmax
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Marshall Islands March 31-April 11, 2008
1-1-4. Basic Characteristic
• Estimate obtained power by I / V curve
A
P
R  0.05()
(A)
N
Then power is 10x0.5=5 W
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PV character
( I/V curve )
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Current(I)
e8 / PPA Solar PV Design Implementation O&M
If the load has 0.05 ohm resistance,
cross point of resistance character and
PV-Character will be following point.
R  0.05()
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Ohm’s theory
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V
I 
R
4
I  V / 0.05
2
0
(V)
0
0.1
0.2
0.3
0.4
0.5
0.6
Voltage(V)
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Marshall Islands March 31-April 11, 2008
1-1-4. Basic Characteristic
• I / V curve vs. Insolation intensity
•Current is affected largely by change
of insolation intensity.
5A
•Partially shaded serial cell will
produce current mismatch.
(A)
N
P
Bypass Diode
Mismatch
1A
High intensity insolation
N
5A
Current(I)
e8 / PPA Solar PV Design Implementation O&M
P
P
Low intensity insolation
5A
1A
Bypass
Diode
N
P
IxV=W
1A
(V)
4A
N
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• Temperature and efficiency
•When module temperature rises up, efficiency decreases.
•The module must be cooled by natural ventilation, etc.
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Efficiency (%)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-4. Basic Characteristic
Crystalline cell
2%
down
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10
Amorphous cell
8
6
Typical
(25C)
4
0
10
20 30 40 50 60 70
Module Temperature (deg.C)
Summer time
on roof top
(65C)
80
90
100
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Marshall Islands March 31-April 11, 2008
1-1-5. Case sturdy
1.Maximum power control
Q : Calculate how much power you can get by following three
resistance. ( I / V curve is next page)
P
R  0.02()
e8 / PPA Solar PV Design Implementation O&M
N
P
R  0.05()
N
P
R  0.10()
N
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1.Maximum power control
(A)
V
I 
R
I/V curve of current insolation.
12
10
Current(I)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-1-5. Case sturdy
8
6
4
2
0
(V)
0
0.1
0.2
0.3
0.4
0.5
0.6
Voltage(V)
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e8 / PPA Solar PV Design Implementation O&M
1-1-5. Case sturdy
2.Temperature vs. Efficiency
Q: There is 50 kW Crystalline PV system.
If surface temperature rises from 25ºC to 65ºC, How much
the capacity will be?
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