The sun is a huge ball of fire which gives light and energy to life on this earth. Apart from the energy which is derived by the plants in human food chain, there is another way of harnessing it directly – in the form of electrical energy.
Introduction
The statistics of this celestial body are spectacular with an age of 4.5 billions years, situated at 93 million miles from the earth and having a core temperature of 14 million (it is not a typing mistake) Celsius. Even the surface of the sun is nearly 5500 degrees Celsius hot. I don’t think I need to tell you that I am talking about the fireball of the universe namely our sun. Well we all see it rise on the horizon each morning (except perhaps the lazy ones) and set in the evening, but have you ever realized how this tremendous source of light and heat can be utilized for our everyday needs. Well apart from using sunlight for our daytime lighting, it can also be used to generate and store electricity to be used when it sets and this is known as solar energy.
Solar Energy
The term solar energy or solar power refers to the energy that is generated by converting the energy inherent in the radiation from the sun into electrical energy by various means such as use of solar panels and so forth. We will study the advantages of solar energy vis-à-vis other types of renewable sources such as wind power, tidal power and so on, in the future articles, but you can certainly imagine that the sunlight is certainly more predictable than say wind that blows in a region.
The Power of the Sun
You had a glimpse of the power inherent in the sun in the form of its core and surface temperature but since the sun is situated nearly 150 million kilometers, the full effect of that heat energy is not experienced on our earth (thankfully so). First we must understand the amount of energy which actually reaches the surface of the earth. This is important since (at the current stage of technology at least) we propose to build solar energy stations on the surface of the earth. Also remember that the earth is not simply a sphere of solid material but also surrounded by various layers of the atmosphere. I suggest you take a good look at the picture in figure 1 which beautifully depicts the amount of solar energy of different regions of the entire spectrum and their level of penetration till the earth’s surface.
Of course the distribution of this energy and the quantitative measure of the energy reaching the surface of the earth varies with geographical location and time of the year. We will study this phenomenon in more detail in the next articles in this series.
Figure 1: Solar Energy in Earth's Atmosphere
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