Solar radiations range in frequencies from infrared through the visible to ultraviolet frequencies. We receive light through the visible radiations and heat through the infrared radiations. We have been learning now how versatile solar energy is.
Even in the ancient times people made use of the solar radiation for heating water and warming houses in winter. In recent years, thanks to technological advances, solar energy is being used for applications ranging from domestic hot water supply or space heating of large buildings, to providing steam and hot water for industrial processes and for providing steam in large thermal power stations to supplement power generation.
Modern developments have given a new angle to the use of solar energy. Invention and later developments of photovoltaic (PV) cells has made it possible for us to convert energy from the visible radiations into electricity. Individual solar cells which are small are assembled in various configurations as arrays and panels; these solar arrays and panels can generate sufficient electricity for practical applications.
Arrays of PV cells are being used in remote and inaccessible communities to provide clean power and they are being used to run cars. PV cells supply power on satellites and space stations and even supplement power generation in power stations of hundreds of MW. Growing at a rate of 40% since the year 2000, installed capacity of solar electric production has touched 10.6 GW in 2007.
The above two instances of the use of solar energy are the very obvious and very much talked about ones. But come to think of it, there is hardly any renewable energy source that does not link back to the versatile solar energy.
Think of wind energy. Gentle movement of air is breeze; more robust movement of air is wind. Unequal heating and cooling of different parts of land and water by solar radiation creates convection currents which result in wind. Windmills are driven by the kinetic energy of the wind. Solar energy is responsible for the heating of the land and the water masses; thus it is the solar heat that is responsible for creating wind. So really speaking, wind serves merely as a carrier of the versatile solar energy.
Similar is the case with tidal energy. Tides result from the interaction of gravitational pulls of the sun and the moon on the water bodies on earth coupled with the rotation of earth. Once again we find the sun is instrumental in creating the tidal waves which we are trying to harness to extract energy from.
Biomass is being used as a renewable source of energy. A little thought tells us that the energy biomass gives out is the solar energy stored in the form of carbohydrates and by burning the biomass – which is burning the carbohydrates – we are releasing that stored solar heat. Again it is the versatile solar energy in a different form that we are using.
The fossil fuel that we are using in every walk of life today is also another example of stored solar energy. Fossil fuel has resulted from animal remains, biomass, etc millions of years ago. Once again fossil fuels are a form of stored solar energy, just as we said biomass is the stored solar energy.
We said at the outset of this article that solar energy is very versatile. As seen by these few examples above, we have been utilizing versatile solar energy in many forms.