When one thinks about solar power, medium sized black panels jump to our minds. But how do these black panels really work? How is the power generated in these black panels and used to operate our every day appliances? Well let us examine the whole cycle of solar energy conversion.
First, you have billions and billions of Watt.hrs of energy being sprayed on the earth from the sun. This energy is commonly known as solar radiation. A Watt.hr is a unit of measuring energy. Power in Watts is basically the speed at which you either gain or lose energy. Solar radiation is measured in Watts per square feet per day. So for example, in Egypt solar radiation is 600 Watt.hrs/sq.ft/day. So you can then infer that 600 Watt.hrs of solar energy is gathered 1 sq.foot of land in 1 day's time. Now using solar cells we can convert this solar energy into electrical energy.
Second, solar cells. How do they work? Well it’s actually very simple. The solar cells we see every day on our calculators are called PV cells for short or Photo Voltaic cells. PV cells are used to convert solar energy into electrical energy. A group of PV cells connected together electrically and placed side by side physically is called a module. Modules are in turn connected to each other electrically and placed side by side to form a solar panel. A large array of solar panels can then be formulated by placing solar panels side by side in close vicinity, but in such a way that no panel shades on another. So spacing is an important factor. Photo Voltaic cells are made of unique semiconductors silicon, which is most commonly used these days. Basically, when solar radiation hits the solar cells, a portion of the energy is absorbed within the semiconductor. The energy of the absorbed radiation completely frees the loose electrons of silicon atoms, allowing them to circulate through electrical circuits.
Finally, electrical power coming out of solar panels is in the Direct Current form or (DC), meaning that the voltage potential difference produced between panel terminals is constant. Most of our appliances operate on Alternating Current or (AC) meaning that the voltage at its terminals has to be varying with a certain frequency. So the DC voltage produced by the solar cells has to be converted to AC voltage in order to be connected to our home grids. This could be accomplished with an electrical inverter. Once the DC voltage is converted to AC using the inverter, the AC terminal of the inverter could be connected to our home or even national grids. So through solar panels and arrays, a clean and zero carbon emitting energy source is efficiently utilized.