Solar panels take advantage of a powerful yet free energy source – the sun. In a single hour, the sun transmits more energy to the earth’s surface than the world uses in a year.
Solar PV uses this energy from the sun to produce electricity, which you can then use in your home as well as export the electricity you don’t consumer back to the grid.
PV cells are thin layers of semi-conducting material (usually silicon). Electrical charges are generated when the silicon is exposed to light, as a result a current is generated which can be conducted away as DC current. Multiple of cells are connected together (usually behind glass) to form a panel, and then multiple panels are connected together to make an array which is what is seen on your roof.