What is a PV (Photovoltaic) system?
The word photovoltaic links the two words ‘photo’, meaning light, and ‘voltaic’, referring to the production of electricity. Photovoltaic systems use sunlight to be converted into energy. Photovoltaic cells are made of semi-conducting materials, so when the sunlight strikes, it is converted into electricity.
How does a PV system work?
PV cells work in full sunlight, and when the sun is overcast. This is because PV cells also diffuse solar radiation, which is light that has been scattered by dust and water particles in the atmosphere.
During the night, as there is no sunlight, PV systems will not generate energy, however the system is able to store collected energy in a battery for non- daylight hours.
Types of PV system:
This is the most popular type of solar PV system for homes and businesses. The PV system is connected to the local electricity network, which allows any excess solar electricity produced to be sold back. Electricity is taken back from the network outside daylight hours. An inverter is used to convert the DC power produced by the solar system to AC power needed to run normal electrical equipment.
Completely independent of the grid, the solar system is directly connected to a battery which stores the electricity generated and acts as the main power supply. An inverter can be used to provide AC power, enabling the use of normal appliances without mains power.
A solar system can be combined with another source of power – a biomass generator, a wind turbine or diesel generator – to ensure a consistent supply of electricity. A hybrid system can be grid connect, stand alone or grid support.
Advantages of a PV system
- Can be designed for a variety of applications and operational requirements
- Can be used for either centralized or distributed power generation
- No moving parts
- Easily expandable
- Energy independence
- Environmental compatibility
- Sunlight is free
- No noise or pollution created
- Minimal maintenance (when properly installed)
- Long life time use
Disadvantages of a PV System
- High cost
- Surface area requirement for PV arrays may be a limiting factor