Simple explanation - Solar Panels use light energy
(photons) from the sun to generate electricity. The majority of
modules use wafer-based crystalline silicon cells or a thin-film
cell based on cadmium telluride or silicon.
Most modules are rigid, but there are some flexible modules
available, based on thin-film cells. Electrical connections are
made in series to achieve a desired output voltage and/or in
parallel to provide a desired amount of current source
capability.
Depending on construction the photovoltaic can cover a range of
frequencies of light and can produce electricity from them, but
sometimes cannot cover the entire solar spectrum (specifically,
ultraviolet, infrared and low or diffused light). Hence much of
incident sunlight energy is wasted when used for solar panels,
although they can give far higher efficiencies if illuminated
with monochromatic light. Sunlight conversion rates (module
efficiencies) can vary from 5-18% in commercial production, that
can be lower than cell conversion.
Third generation solar cells are advanced thin-film cells.They
produce high-efficiency conversion at low cost.
Module performance and lifetime
Module performance is generally rated under Standard Test
Conditions (STC) : irradiance of 1000 W/m˛, solar spectrum of AM
1.5 and module temperature at
25°C.
Electrical characteristics include nominal power (PMAX, measured
in W), open circuit voltage (VOC), short circuit current (ISC,
measured in Amperes), maximum power voltage (VMPP), maximum
power current (IMPP) and module efficiency (%). In kWp, kW is
kilowatt and the p means “peak” as peak performance.
Solar panels must withstand heat, cold, rain and hail for many
years. Many Crystalline silicon module manufacturers offer
warranties that guarantee electrical production for 10 years at
90% of rated power output and 25 years at 80%.
Standards
Standard generally used in photovoltaic panels are:
IEC 61215 (crystalline silicon performance).
IEC 61646 (thin film performance)
IEC 61730 (all modules, safety)
UL 1703
CE mark
Electrical Safety Tester (EST) Series (EST-460, EST-22V,
EST-22H, EST-110).
Worldwide installed totals
World solar photovoltaic (PV) installations were 2.826
gigawatts peak (GWp) in 2007, and 5.95 gigawatts in 2008, a 110%
increase. The three leading countries (Germany, Japan and the
US) represent nearly 89% of the total worldwide PV installed
capacity.
Germany was the fastest growing major PV market in the world
from 2006 to 2007. By 2008, 5.337 GWp of PV was installed, or
35% of the world total. The German PV industry generates over 10
000 jobs in production, distribution and installation. By the
end of 2006, nearly 88% of all solar PV installations in the EU
were in grid-tied applications in Germany.
Photovoltaic power capacity is measured as maximum power output
under standardized test conditions (STC) in "Wp" (Watts peak).
The actual power output at a particular point in time may be
less than or greater than this standardized, or "rated," value,
depending on geographical location, time of day, weather
conditions, and other factors.
Solar photovoltaic array capacity factors are typically under
25%, which is lower than many other industrial sources of
electricity.Therefore the 2008 installed base peak output would
have provided an average output of 3.04 GW. This represented
0.15 percent of global demand at the time. |
PV Panels
