The earth receives a small fraction of the energy that is released by the sun. Yet that small fraction has been estimated to be at least 90 petawatts which is estimated to be at least 6,000 times bigger than daily global electricity consumption 0f 15 terawatts. This is the main reason why solar energy is the most promising source of electricity for the future.
Harnessing solar power is not a new idea. Remember the story of how Archimedes was able to burn enemy ships by using mirrors to concentrate the sun’s rays on the vessels? While the story may not have happened, it only confirms that people have already been thinking of harnessing the sun’s power since ancient times.
Solar cells are actually the PV or photovoltaic cells that act as semiconductors in the process. Like diodes in electronic devices and components, solar cells have similar characteristics. The sun’s rays will hit the solar cell surface, the electrons within become energized, and these in turn are brought to a higher level causing there to be a creation of electricity.
The difference between the solar cells that powered calculators maybe ten years ago to modern photovoltaic cells that are used to generate household electricity is efficiency or energy conversion ratio. Today’s solar cells are able to convert 24 percent of the energy found in sunlight to electricity while older solar cells had a conversion efficiency of less than 10 percent. Research in the industry and academe indicates that energy conversion ratios may rise to more than 40 percent.
Raw electricity outputted by solar panels is not directly usable. The direct current produced by the panels has to be converted to alternating current using inverters. Solar panels only work during daytime. Therefore there is a need to store the electricity so that it becomes available for 24 hours.
For photovoltaic panels that are isolated from the grid, lead acid batteries are the most popular storage medium for solar power generated electricity. When it is possible to connect solar panels to the main grid, current practice is to earn credits by selling electricity to the system. At night time, these credits are used to buy electricity.
Daily, sunlight travels to the earth and can reach up to energy proportions measuring to 90 petawatts. In one day a human can use up to 15 terawatts in energy consumption. 90 petawatts is roughly 15 terawatts times 6,000!
Solar towers are a promising technology which will make idle desert lands productive. The Sahara and Gobi Deserts could be future sites of concentrated solar power plants generating clean electricity. Countries like Spain and Germany are the current leaders in production of electricity via CSP.
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