‘Photovoltaic’ is formed from the Greek word ‘photo’ (for
light) and the surname of physicist 'Alessandro Volta'. The unit of
measurement for electrical voltage (Volt) is named after him.
Photovoltaic thus means ‘voltage (electricity) from light’.
When solar or light energy is utilised with a photovoltaic plant,
the sun’s rays are converted directly into electrical energy by means of
solar modules. Even diffuse light from overcast skies is used.
The light from the sun contains photons. When these photons strike
an atom in a solar cell, they throw individual electrons out of their
orbit. These released electrons then seek new atoms and are accepted
into their orbits. Solar cells are put together in several thin layers. The
elaborate manufacturing process ensures that these free electrons can
only flow in one direction – and an electrical current is created.
Individual solar cells made of silicon are joined together to make solar
modules, which can then be mounted on roofs.
An inverter then uses the direct current supplied by the solar cells to
produce alternating current. This current is fed into the electrical
network of the responsible energy supplying company and paid for accordingly, or it can be used for one’s own consumption.