Introduction to Photovoltaics
Dennis ScanlinAppalachian State University
Photovoltaic History• 1839 Edmund
Becquerel - first recognized the effect
Early PV milestones• 1839 – discovery of the
photovoltaic effect; • 1873 – Smith discovers
the photoconductivity of selenium
• 1883 – Fritts develops first selenium cell (1% efficient)
• 1904 – Einstein published his paper on the photoelectric effect (along with a paper on his theory of relativity)
• 1921 – Albert Einstein wins the Nobel Prize for his theories (1904 paper) explaining the photoelectric effect
Albert Einstein
P-N Junction & 1st cells• Technology
Developed at Bell Labs in 1940’s & 50’s
• Patented 1st modern solar cell called a “Light sensitive device”
Vanguard I - first PV powered satellite
• Launched in 1958; 4th artificial satellite
• solar panel: 0.1W, 100 cm²
• Still orbiting; longest orbiting artificial satellite
• $1000/watt
Contemporary Applications:Direct Power Water Pumping or Air Moving
Direct Power
Contemporary Applications:Off Grid Battery Based Systems
Off Grid Battery Based Systems
Offgrid Battery Based System
Hybrid Systems Wind Turbine
Tower
Wind Charge
Controller
Battery Bank
120/240 VAC Loads
DC Loads
DC Source Center PV Charge
Controller
PV Array (Optional)
DC - AC Inverter
System Controls Not Shown
Engine Generator (Optional)
Grid Tied Battery Based Systems
Battery Charging Systems
Direct Grid Tie Batteryless Systems
Direct Grid Tie PV
Direct Grid Tie Inverters
Direct Grid Tied PV: Residential
Number of Residential vs Commercial Systems Installed
Direct Grid Tied Utility Scale Photovoltaic Systems
Annual US Installed Grid PV
Mounting Hardware
Photovoltaic Production, by Country or Region, 1994–2007
0
200
400
600
800
1,000
1,200
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Source: Maycock and Prometheus Institute
Meg
awat
ts
United States Japan Europe China
PV Production by Country
Types of PV Cells/Products
• Single Crystalline
• Polycrystalline
• String Ribbon
• Amorphous or Thin Film
Shipments of PV by Type
Effic
ienc
y (%
)
Universityof Maine
Boeing
Boeing
Boeing
BoeingARCO
NREL
Boeing
Euro-CIS
200019951990198519801975
NREL/Spectrolab
NRELNREL
JapanEnergy
Spire
No. CarolinaState University
Multijunction ConcentratorsThree-junction (2-terminal, monolithic)Two-junction (2-terminal, monolithic)
Crystalline Si CellsSingle crystalMulticrystallineThin Si
Thin Film TechnologiesCu(In,Ga)Se2
CdTe
Amorphous Si:H (stabilized)Emerging PV
Organic cells Varian
RCA
Solarex
UNSW
UNSW
ARCO
UNSWUNSW
UNSWSpire Stanford
Westing-house
UNSWGeorgia TechGeorgia Tech Sharp
AstroPower
NREL
AstroPower
Spectrolab
NREL
Masushita
MonosolarKodak
Kodak
AMETEK
PhotonEnergy
UniversitySo. Florida
NREL
NREL
Princeton
UniversityKonstanz NREL
NRELCu(In,Ga)Se2
14x concentration
NREL
UnitedSolar
United Solar
RCA
RCARCA
RCARCA
RCA
026587136
Spectrolab
University CaliforniaBerkeley
Solarex
12
8
4
0
16
20
24
28
32
36
Best Research-Cell Efficiencies
Concentrating PV
PV Prices
Cost of Energy