How Do Solar Cells Convert Light into Electricity?
- Photovoltaic cells are the basic units of a solar power system. These solar cells are made of a silicon-based material that absorbs sunlight. The cells are relatively small---their diameters range from ½ inch to 4 inches. The small size converts to small power outputs. Each cell is capable of a one to two watts. These cells are encased in a weather resistant module. For higher power outputs, multiple modules can be linked together in an array, a term used to describe all of the modules that are linked together. In solar power plants, a couple thousand modules can be linked together.
- Sunlight is composed of particles of light energy, also known as photons. When these particles of light energy hit the photo, some will deflect or pass through, but others will dislodge electrons on the silicon. The silicon has been treated to allow free electrons to gather on one side. When enough electrons have been forced to one side, it creates a potential difference between the two sides of the cell. The cell now is similar to a battery, with a positive side and a negative side. Once the cell is connected to an external load, it starts supplying energy.
- Solar power has several advantages and disadvantages as a power source. Solar power doesn't take much space because the modules can convert light directly to electricity. Because of the connectivity of the modules, just about any amount of electricity can be generated. Solar power is also gentle on the environment because it gives off no harmful emissions. However, solar energy is not without its flaws. Since solar power depends on sunlight, on cloudy days the modules will not generate any power, so solar power can be unreliable.
