What do we mean by Photovoltaic or PV?
First used in about 1890, the word has two parts: photo, derived from the Greek word for light, and volt, relating to the electricity pioneer Alessandro Volta. So, photovoltaics could literally be translated as light-electricity.
And that’s what photovoltaic (PV) materials and devices do — they convert light energy into electrical energy (Photoelectric Effect), as discovered by renowned physicist Albert Einstein.
Commonly known as solar cells, individual PV cells are electricity-producing devices made of semiconductor materials. PV cells come in many sizes and shapes — from smaller than a postage stamp to several inches across.
They are often connected together to form PV modules that may be up to several feet long and a few feet wide. Modules, in turn, can be combined and connected to form PV arrays of different sizes and power output.
The size of an array depends on several factors, such as the amount of sunlight available in a particular location and the needs of the consumer.
The modules of the array make up the major part of a PV system, which can also include electrical connections, mounting hardware, power-conditioning equipment, and batteries that store solar energy for use when the sun isn’t shining. Simple PV systems provide power for many small consumer items, such as calculators and wristwatches.
More complicated systems provide power for communications satellites, water pumps, and the lights, appliances, and machines in some people’s homes and workplaces. Many road and traffic signs along highways are now powered by PV. In many cases, PV power is the least expensive form of electricity for performing these tasks.
Solar energy technologies use solar radiation for practical ends. Solar technologies such as photo-voltaics and water heaters increase the supply of energy and may be characterized as supply side technologies.
Technologies such as passive design and shading devices reduce the need for alternate resources and may be characterized as demand side. Optimizing the performance of solar technologies is often a matter of controlling the resource rather than simply maximizing its collection.