PV Cells (Photovoltaic Cells)
Photovoltaic (PV) cells convert sunlight into electricity. They are
constructed using semi-conductors (materials that conduct electricity
but not as well as conductors, such as metals). Silicon is commonly the
semi-conductor used in solar energy systems. There are usually two
layers of semi-conductors in a PV cell and different impurities are
added to each layer. When sunlight hits these semi-conductors electrons
are displaced and these electrons flow between the semi-conductors
creating an electric current. Metal is used to draw the current away
from the PV cells. An inverter may be used to convert the type of
electricity to that used in households.
PV cells may be linked together in panels to generate large amounts of
electricity.
PV cells have been used in space for many years, as well as in
small-scale items such as calculators. They are also now being used to
power buildings and cars in some parts of the world.
The world’s largest PV plant is being built by General Electric in
Portugal. It will generate enough electricity to power 8,000 homes. This
will mean a reduction in 30,000 tonnes of greenhouses gases a year.
There is a farm of solar panels in Leipzig
Germany, where 33,000 solar panels generate up to 5 MW of power, enough
to supply 1,800 homes.
 |
Guest Book |
|
|
