How is solar energy produced?
In today's climate of growing energy needs and increasing environmental concern, there is a need to have alternative ways of producing energy in the form of renewable and non-polluting fuels. There are many alternatives like the Wind Power, Bio-gas, Tidal Energy and most importantly and widely used is the solar energy.
Solar energy is the energy naturally received from the Sun, in the form of Light and Heat. We can use its power or qualities for particular purpose, by various technologies like solar heating, solar or thermal electricity.
Solar technologies are broadly classified as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of solar panels and solar collectors to control the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
Image of solar panel on a rooftop
It is important to understand that light is a form of electro-magnetic energy. It can be converted into electric energy, if the light energy received is sufficient in strength. There are cells that receive light and get energised and can convert the light into electricity. These cells are called ‘Photovoltaic’ cells. A photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics—e.g. current, voltage, or resistance—vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source. The electricity is produced because the resistance changes as the cells get heated and this results in generating electric current. Solar energy is produced by sun rays in the solar panels by placing them on roof top, directly under the sun. Solar panels are made by putting together large no. of “Photovoltaic Cell”. Solar cells convert light energy into electricity.
Image of a photovoltaic cell
These solar panels also consist of heat collectors. Water pipes are passed through these heaters and the water in the pipes is heated. Once water is heated it is collected in a storage tank. Thus heated water for domestic use is formed with the help of solar energy. These heat collectors are also used to heat home at night or on a cloudy day.
In Industries, a very large nos. of mirrors are used which focuses sunlight on a furnace, which produces intense heat which is used for various industrial processes. This technology is called Concentrating Solar Power Technology (CSP).
CSP produces usable energy from sun light by using lenses and mirrors that focus light to produce heat which is used in conventional power plants to generate electricity which then can be issued to industry and domestic users.
Solar energy has been used by humans for a long time for uses such as heating, cooking food, removing salt from seawater and drying clothes. Heating water for bathing is a very common usage in the cities.
Passive solar energy technology is used in various fields such as architecture in urban planning, agriculture, horticulture in greenhouses, in transport (solar powered cars and boats) and in water treatment.
Global advantages of solar energy are: it reduces pollution, costs on energy production are low, if used as alternative to fossil fuels this technology could reduce fuel costs, source is inexhaustible and thus the energy is renewable and a nation’s import bills could reduce. Though the initial set up costs are more, the long term costs are quite low. However, this energy has one disadvantage that the space requirements for solar panels to produce larger quantum of energy is huge and thus, this source is more useful for a limited area.