How do residential solar panels work? This is an often and misunderstood question many people have about solar power technologies.
Photovoltaic electric systems convert sunlight into electricity.
Each PV system is made up with a series of photovoltaic cells. These are the basic components of a PV system that are made up of semi-conductor materials such as silicone. When the sun's light is absorbed by the semi-conductor materials, the energy contained inside the sunlight frees electrons from the atoms of the material and creates an electrical current. The process is also known as the "photoelectric effect".
In the photoelectric effect, free electrons from atoms travel in an electric circuit that is built into the back side of photovoltaic cells. The sunlight of a certain wavelength will work efficiency to create an electrical flow. Even if the day is cloudy, PV systems can still produce electricity, but not as much as on a clear sunny day.
Each cell is capable of producing a small amount of electrical power. To generate enough electricity in sufficient amounts, cells need to be connected together inside the panels or modules. Typically, about 40 cells or more are connected together in the panels or modules. The output of the panels will range anywhere from 10 to 300 watts. Panels can be interconnected together to form an array which is usually seen on roof tops of homes or at ground-level.
When mounting arrays of PV panels, these arrays can be mounted in one of two ways. The first way is mounting them facing the compass direction "south" at a fixed angle. A second way is to mount the arrays on tracking devices. These devices will allow the array to track the path of the sun. The second method allows the PV arrays to capture a greater amount of sunlight during the day.
The design of a residential solar panel system can be very flexible in meeting the electrical requirements regardless of how big or small they may be. These systems can be connected to the utility distribution system as grid tie systems or as a off grid systems that work independent of the utility.
Image Credit: U.S. Department of Energy
The diagram seen above shows a grid tie system that is connected to the electric utility system. Notice in this diagram the square panels of the array on the roof top of the home. Each panel of the array contains nine smaller squares. The energy generated by these panels will travel to an inverter. The energy will travel from the inverter to the loads inside the house. If there is any extra (excess) energy generated by the panels, it will flow to the home's electric meter and then into the utility's grid system. In the example above, electricity being generated by the panels of this home is providing electric energy for lights, a television and a clothes washer and dryer.