The term ‘photovoltaic’ has been used since 1849, in relation to solar cells. The word originates from Greek, literally meaning ‘light-volt’, or a source of electricity generated by the sun’s light. Photovoltaic cells are a type of solar cell, which can currently supply 1% of the world’s electrical demand.
Normal solar panels work by using energy from the sun to generate hot water and steam, but photovoltaic systems directly produce electricity. They use semi-conductive silicon with impurities, which cause electrons to be freed from silicon when sunlight strikes the cell. The movement of these electrons produces an electrical charge, generating a DC current.
These systems are already used globally. On a small scale, these cells can be used to power street lamps, offshore navigational aids, and even calculators. In La Garrotxa, Spain, 60 homes are powered by photovoltaic systems alone. These systems can be made portable, and in Africa are mounted onto camels to power refrigerators, so vaccines can be delivered to remote locations.
Last modified: 25th April 2016