Solar energy was first discovered in 1839 by the physicist Alexandre-Edmond Becquerel. The term "photovoltaic" originates from the driving force behind this technology, the light beam. (A light beam consists of very tiny particles called photons).
The Science Bit
A pure silicon solar cell features four electrons in the outer electron shell of the atomic nucleus, the valence electrons. Sunlight bombards the solar cells providing the electrons with energy, at this point; the electrons are finally knocked off the silicon atom and leave a positive atom behind.
The free electrons move around allowing a current to be generated. For them to move in the right direction the front surface and the back surface of the cells need to be polarized differently.
Converting power
DC generated in the solar modules can be used in the house or fed into the grid, provided it is first converted into AC electricity. This is the core task of an inverter which is a complex link between the solar modules and the grid.
How Do Inverters Work?
After sunrise, as soon as there is sufficient output generated by the solar modules, the control unit starts monitoring the voltage and frequency and the amount of energy available. Once enough sunlight is received, the inverter starts feeding the grid. Different inverters are designed to be used with a range of solar modules which have a wide range of input voltages.
The inverter will now continue to work in a way to always draw the maximum amount of power from the solar modules. This function is called MPPT (Maximum Power Point Tracking) and is carried out with a rate of accuracy of more than 99%. After dark, when the energy offered is no longer enough to feed the grid, the inverter automatically cuts the connection to the grid and stops operating.