When you see solar panels on someone's roof, you know that that person has invested in a solar power system, but have you ever stopped to think what extra components are needed for a system to work? Here is a complete guide to all the elements you need for a solar power system.
PV (photovoltaic) panels are the most common type of panel, especially for residential installations. They are made from three layers:
* The N-Layer – silicon that is mixed with phosphorus
* The P/N Junction – pure silicon
* The P-Layer – silicon that is mixed with boron
When sunlight strikes the N-Layer, it knocks electrons loose. These electrons pass through the P/N junction (which is a one-way junction) into the P-Layer. This creates an electrical field that then drives the electrons that have been “knocked off” from the silicon, creating an electric current.
If you know your physics, then you will know that the electric current that is generated in this way is direct current (DC), which is like the electricity stored in batteries. However, mains electricity is alternating current (AC) where the flow of electricity changes direction 50 times a second. To make the electricity supplied by solar power suitable for use in domestic homes, a device is needed that converts DC current to AC current, and this device is called an inverter.
An inverter works in a very simple way, using a series of switches which are known as “solid state switches” that “flips” the DC current backwards and forwards 50 times a second, to create the AC current.
Not all solar power systems have a battery, but some systems that produce more electricity than is needed for the building they are powering have a battery connected to store this excess energy. The stored energy can then be used when the solar panels are not providing enough energy, such as dark and rainy days.
The distributor is the device that distributes the AC power created by the inverter to the grid, and sometimes to both the home in which the solar power system has been installed and the grid. The output from the inverter is fed to a dedicated breaker in your house's electric panel, and then through to your home. If you are creating more power then you are using, then some of the power flows backwards and into the grid, and you receive a credit from your utilities company. If your system is not supplying enough energy for your home, then the shortfall is made up as usual by your utilities company.
These are the basic components of any solar energy system and as you can see, solar power is not a complex energy system – the cells create DC current, the inverter changes it to AC current, and the distributor controls the way in which power is distributed between your home and your utilities supplier.