What is Photovoltaic Energy?
The word “photovoltaic” is a combination of two words - “photo”, meaning light, and “voltaic”, meaning electricity. Therefore photovoltaic technology, the scientific term used to describe solar energy, involves the generation of electricity from light.
The secret to this process is the use of a semi-conductor material which can be adapted to release electrons, the negatively charged particles which form the basis of electricity. The most commonly used semi-conductor material used in photovoltaic (PV) cells is silicon, an element most commonly found in sand.
All PV cells have at least two layers of such 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 current. The greater the intensity of the light, the greater the flow of electricity.
A photovoltaic system does not therefore need bright sunlight in order to operate. It also generates electricity on cloudy days, with its energy output proportionate to the density of the clouds. Due to the reflection of sunlight, slightly cloudy days even result in higher energy yields than days with a completely blue sky.
Solar PV is quite different from a solar thermal system, where the sun’s rays are used to generate heat, usually for hot water in a house, swimming pool etc.
The Advantages of Solar Power
- The fuel is free
- No moving parts to wear out or break down
- Minimal maintenance required to keep the system running
- Modular systems can be quickly installed anywhere
- Produces no noise, harmful emissions or polluting gases