The term photovoltaic is a combination of two words: “photo,” meaning light, and “voltaic,” meaning electricity. Photovoltaic technology is the term used to describe the hardware that converts solar energy into usable power, which generates electricity from light.
At the heart of PV technology is a semi-conductor material which can be adapted to release electrons, the negatively charged particles that form the basis of electricity. The main semi-conductor material used in photovoltaic cells is silicon, an element most commonly found in sand. There is no limitation to its availability as a raw material as silicon is the second most abundant material in the earth’s mass.
All PV cells have two layers of semi-conductors, one positively charged and one negatively charged. When light shines on the semi-conductor, the electric field across the junction between these two layers causes electricity to flow, generating DC (direct current). The greater the intensity of the light, the greater the flow of electricity.
A photovoltaic system therefore does not need bright sunlight in order to operate. It can also generate electricity on cloudy days. Due to the reflection of sunlight, slightly clouded days can even result in higher energy yields than days with a completely cloudless sky.