A
solar photovoltaic (PV) cell is an electronic
device that produces electricity when light falls
on it. As the light is absorbed by the PV cell
it frees up electrons present in the cell, as
the electrons move from the cell, they carry with
them an electrical charge and are sent to a load
such as a calculator or to storage, such as a
battery.
A
single PV cell can only absorb a small amount
of light at a time. So several cells are usually
interconnected to form modules to provide larger
amounts of electricity. Groups of modules can
be mounted together to form a panel. Panels can
be interconnected to form a photovoltaic array;
these can vary in electrical power depending upon
size, from a few watts to thousands. These systems
can last a long time; the expected life span is
at least 25 years.
PV
panels and arrays are becoming increasingly popular
and being deployed around the world. Their potential
as stand-alone systems is recognised particularly
in areas where grid-connected electricity is not
available. PV panels are also being integrated
into existing buildings by replacing the traditional
materials of the roofs and facades. Buildings
with PV panels which generating more electricity
than they use can sell back the surplus power
to the national grid.
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