The sun has been burning bright for millennia – long, long before mankind evolved. The earth’s natural resources were sufficient to meet the needs of the population for thousands of years. And then just over a few hundred years, life on earth changed unimaginably. With the onset of industrialization and rapid advances in technology, mankind’s hunger for energy is now insatiable. The result? Rapid depletion of natural resources and serious threats to our environment. Today, mankind has no option, but to look at the sun as a source of energy.
What exactly is Solar Energy?
To put it in a nutshell, solar energy is a technology that is used to harness the power of the sun and make it usable for mankind. While there has been a rise in the use of solar energy, in 2011, it was estimated that the total solar energy produced was less than 0.1% of global energy demand.
Solar Energy can be generated at a roof site, in farms or in a solar-thermal plant. In the first and the second case, photovoltaic cells – better known as solar modules are used. These cells are made up of semiconductor materials, similar to those found in computer chips. When the sun light falls on these cells, it knocks the electrons loose from their atoms. And as electrons flow through the cell, electricity is generated. Solar-thermal plants operate on a much grander scale. They employ different methods to concentrate the sun’s energy as a source of heat. This heat is then used to boil water to drive a steam turbine that generates electricity. This is a little similar to how coal and nuclear power plants generate and supply power to thousands of households.
How is Solar Energy harnessed?
One of the methods of harnessing is the use of long troughs of U-shaped mirrors to focus sunlight on a pipe of oil that runs through the middle. The hot oil boils water which is then used for generation of power. Another technique is the use of moveable mirrors to focus the sun’s light on a tower which houses a receiver. Molten salt flows through the receiver to heat it and run a generator.
There are other passive methods. One of them is placing large windows on the sunny side of a building to let sunlight heat be absorbed in materials on floors and walls. Absorbent plates on a roof can heat liquids in tubes and supply a house with hot water.
Solar energy is considered to be inexhaustible without the unpleasant side effects of pollution. It can also be put to a variety of other uses. Solar cells generate power in satellites that orbit our planet. They can also power distant dwellings as easily as they can power buildings and cars.
What are the pitfalls?
The most glaring and obvious drawback of solar energy is that it doesn’t work at night. In cloudy weather, it can be unreliable. Solar kits and technology can be expensive, and a lot of land area is required to collect the sun’s rays.
However, despite the challenges, solar energy use is growing at a rapid rate of 20% a year in the last 15 years – primarily due to falling prices of installation and increase in efficiencies. With a lot of countries giving tax incentives and other subsidies, it is very likely that solar electricity will become a part and parcel of our lives in the next 5 to 10 years.