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What is the current market for
solar-cell/photovoltaic (PV) manufacturing sector?
The combined PV equipment and materials sector generated $3.7
billion in 2006, with the polysilicon-driven materials side
accounting for most of the total, according to SEMI. By 2010,
the association forecasts the overall market will top $10
billion, with thin-film tools grabbing an increasing share of
How long will a system last?
average lifetime of a PV module can be in excess of 20 years,
crystalline silicon modules in particular have a very long
life span. In addition, they require very little maintenance.
Other system components will have a varied lifespan, for
example batteries in stand-alone systems can last between 2
and 15 years depending on type.
What applications are there for PV?
PV technology has many applications, both for stand-alone
systems and for integration onto buildings. PV may be used in
applications such as monitoring stations, radio repeater
stations, telephone kiosks and street lighting to name just a
few examples. There is also a substantial market for PV
technology in the leisure industry, with battery chargers for
boats and caravans, as well as for powering garden equipment
such as solar fountains.
In more recent years, PV has become more widely used in urban
areas, where it can be integrated into new buildings or
mounted onto existing buildings. This is a rapidly growing
market. PV technology is ideally suited to the urban
environment, providing pollution and noise free electricity
without using extra space.
PV technology is also widely used in the developing world. The
technology is particularly suited here, where electricity
grids are unreliable or non-existent, with remote locations
often making PV power supply the most economic option. In
addition, many developing countries have a high level of solar
radiation levels year round.
Does PV technology need bright sunshine to
The electrical output of a PV cell is
dependent upon the intensity of the light to which it is
exposed. So PV cells will tend to generate more electricity on
bright days than when skies are overcast. However,
photovoltaics do not need to be in direct sunlight to work, so
even on overcast days a PV cell will be generating some
What types of materials are used in making
a photovoltaic cell?
The most widely used material
for PV cells is silicon, a semiconductor. The silicon is
"doped" (that is, it has a certain amount of impurities placed
into the silicon crystal) with either boron or phosphorus to
give it the properties needed to be a PV cell and give up
electrons when exposed to light. The photons of light (photons
are actually small particles of light) "knock" the electrons
out of the outside band of the silicon atom and that is what
creates the PV effect.
What is thin film technology?
Another approach to producing solar cells that shows great
promise are thin films. Commercial thin films today are
principally made from amorphous silicon; however, copper
indium diselenide and cadmium telluride also show promise as
low-cost solar cells. Thin-film solar cells require very
little material and can be easily manufactured on a large
scale. Manufacturing lends itself to automation and the
fabricated cells can be flexibly sized and incorporated into
What is the history of PV technology?
In 1839, Edmond Becquerel noticed that, in addition to heat,
the sunlight that is absorbed by certain materials can produce
small quantities of electricity. This curious phenomenon was
limited to measuring light levels in photography until the
1950s. Then, the combination of improved purification
techniques for semiconductors, the advances in solid state
devices beginning with the development of the transistor in
1947, and the needs of the emerging space program, led to the
development of photovoltaic cells. In 1954, a 4% efficient
silicon crystal photovoltaic cell was demonstrated. By 1958, a
small silicon array was used to supply electrical power to a
What is photovoltaic (PV)?
PV is a
basic type of solar electric technology. The photovoltaic (PV)
process converts sunlight, the most abundant energy source on
the planet directly into electricity. The equipment required
for this process has no moving parts and as a result requires
minimal maintenance. In addition, the electricity is generated
with no emissions and no noise.
A PV cell consists of two or more thin layers of
semiconducting material, most commonly silicon. When the cell
is exposed to light, electrical charges are generated and this
can be conducted away by metal contacts as direct current
The electrical output from a single cell is small, therefore
multiple cells are connected together to provide a more useful
output. Cells connected in this way are encapsulated (usually
behind glass) to form a weatherproof module or panel.
Multiple modules can likewise be connected together in order
to provide sufficient power for common electrical appliances.
What is an analog signal?
analog or analogue signal is any variable signal continuous in
both time and amplitude. It differs from a digital signal in
that small fluctuations in the signal are meaningful.
What is an ASIC?
application-specific integrated circuit (ASIC) is an
integrated circuit (IC) customised for a particular use,
rather than intended for general-purpose use. For example, a
chip designed solely to run a cell phone is an ASIC. In
contrast, the 7400 series and 4000 series integrated circuits
are logic building blocks that can be wired together to
perform many different applications. Intermediate between
ASICs and standard products are application specific standard