The sun is a non-stop energy source with a tremendous amount of power. For decades scientists searched for ways to use the sun’s energy to generate an electrical current, but it wasn’t until Russell Ohl patented the solar cell in 1941 that the adoption of solar power as a viable source of electricity really took off.
The power of the sun is an amazing phenomenon. Each square foot of the earth receives an average of 164 watts of energy. Imagine a powerful light bulb set up on every square foot of the planet’s surface and you can visualize how much solar energy the earth receives on a constant basis. In fact, if just 1% of the Sahara desert were lined with solar panels it would generate enough energy for the entire world.
If solar energy has a downside it’s that it has to be converted into electrical energy before we can use it to power our home. The sun emits both light and heat to the earth, but neither of these elements automatically transfers into electrical energy. Light is important for making plants grow and heat helps us to survive in space, but it does not run our car or computer. To fix this problem scientists have created a conversion process for turning energy from the sun into usable electricity. This is through a device known as a solar cell or photovoltaic cell. A grouping of many solar cells is called a solar panel.
How Do Solar Panels Work?
Solar panels can be characterized as large rectangular-shaped modules that contain small collectors or cells that gather energy from the sun. These cells are generally only about 1 to 4 inches in diameter and each cell generates just a small amount of electricity (around 1 or 2 watts). The cells are built from silicon, which is a common semiconductor metalloid found in sand. Each cell has both a positive and a negative layer to create an electrical field, similar to that in a battery. As the sun shines on the solar panel the energy is absorbed into the cell, freeing electrons in the solar energy. This results in the flow of electrons known as electricity. The electricity can then exit the panel through a connecting wire.
A large panel typically has many cells that are connected together which combine to create a larger voltage and current. In addition you can also connect a series of solar panels together to form a solar array. The total output of a solar array will depend on a number of factors including the total surface area of the array, the duration and intensity of sunlight and the efficiency of the solar cells. The efficiency of most rooftop solar panels is between 15 and 20 percent, which means only 15 to 20 percent of the light energy that reaches the cell is converted to electricity. Many of the solar panels used on satellites have power efficiencies close to 50 percent, but these types of panels are generally too expensive for home use.
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