A photovoltaic system primarily comprises of the following two components:

1. The array (modules or panels) -usually on installed on an elevated part of a building or on a mounting rig – these panels convert solar energy into DC electricity
2. A wiring system and inverter that connects the array to the building’s internal mains system or battery storage.

PV cells are made from a semi-conducting material, usually silicon and convert the sun's rays into electricity using the “Photovoltaic Effect”.

“Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When these photons strike a PV cell, they can be reflected, absorbed or they may pass right through. Only the absorbed photons generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the cell (which is actually a semiconductor). With its newfound energy, the electron is able to escape from its normal position associated with that atom to become part of the current in an electrical circuit. By leaving this position, the electron causes a "hole" to form. Special electrical properties of the PV cell—a built-in electric field—provide the voltage needed to drive the current through an external load (such as a light bulb)”. Taken from “About Photovoltaics”

A single PV cell only generates a small amount of electricity, so several cells are joined together to form a module. The modules are then wired (strung) together to form an array which is designed to give a certain output depending on the requirement of the end user. The electricity produced by the array is DC. This can be used to directly power DC equipment, charge batteries or power water pumps.

However, in most buildings, AC power is required and to meet this requirement an inverter is installed to convert the DC power to AC power. In addition to this it is possible to feed the electricity produced from the PV system into a building’s mains. Therefore when the PV system is producing power it is fed into the building directly for use and if there is a greater demand for power additional power can be ‘pulled’ in off the grid.