Facts About Solar Energy And Solar Panels
Why bother with facts about solar energy and solar panels?
Renewable energies are the future of human society. With carbon fossils getting more scarce, their prices rising and the environmental issues that arise with their use, more and more countries are already looking for alternatives to fossil fuels. And solar energy is among the favorites, especially for countries that are blessed with sunshine all year round.
In this article, we will focus on the harnessing of solar energy using photovoltaic means (you will get to read more about below). Of course, there are other ways of harnessing solar energy, for example, through Concentrated Solar Power (CSP).
Facts about solar energy development
The supply of solar energy is almost limitless, as long as the sun continues shining. In fact, it is estimated by NASA that we use only about 1/10,000 of the solar energy that reaches the earth. Not only is solar energy in abundance, it is also free! Anyone with the right equipment can collect it and transform it into usable energy. Read more about the advantages of solar energy.
However, one of the reasons why solar energy hasn’t yet replaced the fossil fuels in meeting the world’s need for energy is the problem of transforming sunlight efficiently into sufficient useable energy. Facts about solar energy conversion show that currently, the efficiency of converting solar energy to electricity is limited at about 12% for typical solar panels, and possibly 20% or slightly above for the best available photovoltaic panels. Read more on solar energy efficiency
and the other shortcomings of solar energy
That is not to say that there is no way out of the situation. Solar energy has come a long way since the first photovoltaic cells were invented at the end of the 19th century, after the discovery of the photoconductivity of selenium by William Grylls and Richard Evans. Facts about solar energy show that the publishing of the seminal paper on the photovoltaic effect by Einstein, and the creation of the first silicon photovoltaic cells gave solar energy a big boost, taking it to the stars literally, by powering satellites and astronomical observatories. Read more about the history of solar energy.
In the 70s and 80s, solar energy landed back on earth to power buildings and businesses. Today solar energy is everywhere and it is used to power homes and offices.
Facts about solar energy cells
Here are some facts about solar energy cells and how they transform solar energy into electricity.
Typical solar energy cells generate electricity using the photovoltaic effect. The photovoltaic effect is the creation of an electric current through exposure of the photovoltaic material (e.g. silicon) to the sunlight.
Common photovoltaic solar cells are configured with two layers made from silicon in direct contact with each other. These two silicon layers are called N-type silicon (where there is a high electron concentration) and P-type silicon (where there is a low electron concentration). When the N and P-type silicon layers come into contact with each other, they create an internal electric field that is important for the conversion of solar energy to electricity. Read on.
When light photons from the sun’s rays are absorbed by a photovoltaic material in a solar cell, the energy absorbed excites electrons in the material and releases them. The freed electrons then flow through the photovoltaic material in a single direction, as a result of the internal electric polarity formed by the N and P-type silicon layers. Specifically, the electrons travel from the P-type silicon layer to the N-type silicon layer. And when the electrons flow in a single direction, an external electric current is created. This current is then connected to an external load by means of a semiconductor. This energy is then directed in the form of electricity to houses and buildings. In this way, solar energy is being converted into electricity by means of the solar cell through the photovoltaic effect.
Factors about solar energy cells show that a factor that limits the efficiency of solar energy cells is the range of wavelengths of light that will trigger the photovoltaic effect in the solar cells. Most cells can only produce electricity from absorbing a specific range of light wavelengths. Usually ultraviolet, infrared and diffused light are not able to trigger the photovoltaic effect. The energies from these wavelengths are often wasted as heat. This heat from unused sunlight and the inefficiencies inherent in the solar cells (such as in generating the electrons) account for the loss of more than 50 % of the initial amount of solar energy falling on the solar cell.
In respond to these problems, attempts are made to increase the efficiency of solar energy cells by first splitting sunlight into the different wavelengths and directing rays of specific wavelengths to their corresponding solar cells.
Developments are currently also being made to increase the efficiency of solar cells by harvesting the wasted heat in unused sunlight, through a process known as Photon Enhanced Thermionic Emission, or PETE.
Facts about solar energy panels
Here are some facts about solar energy panels.
Solar energy panels comprise of electrically interconnected solar cells. A single solar cell produces limited amounts of energy, so many cells are needed within a single panel, and at times, several panels are required to produce the desired amount of electricity (depending on the size of the demand).
The solar cells are connected by means of conducting wires. They are then protected from mechanical damage through the use of a frame (could be made of wood) and a transparent cover (could be made of glass). Read about how you can make your own solar panels.
Attempts to increase the efficiency of solar energy panels have led to solar panel designs that include trackers and solar concentrators. Because the position of the sun changes with the time of the day, solar trackers help to orient the solar panels so as to maximize the amount of the sun’s rays that fall directly onto the panels. In turn, solar concentrators help to focus the sun’s rays onto the panels via the use of lenses or mirrors.
Facts about solar energy storage
There are several methods to store excess solar energy. Two of the most common methods are the use of rechargeable batteries and molten salts. These methods allow solar energy to be stored and used at night or on days when the sun is blocked by large clouds.
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