Solar PV power is a kind of renewable generation that depends upon light striking a panel of semi-conductor material. The most common type at present is made of crystalline silicon, with layers which have alternately been doped with phosphorus and boron respectively. When the light strikes the panel, some of the photons release electrons from the silicon, allowing them to travel towards an electrode. The silicon that has been treated with phosphorus behaves differently, in terms of electron release, from that treated with boron, which creates an electrical field at the boundary between the layers, helping the freed electrons to move towards the electrode; from there, they move around an electrical circuit, providing useful energy as they do so. The field also helps the atoms that have lost electrons and are now positively charged to move towards the panel’s positive electrode where they are recombined with electrons from the circuit.