A solar system is made up of solar panels wired together to form a unit. Each solar panel consists of solar cells, which are made of silicon. Solar cells have a positive layer and a negative layer creating an electrical field, like a battery. When photons from the sun hit the solar cell an electrical current is conducted. The electrical current that is created generates the electricity that powers your home.
There are two basic types of currents, direct currents, and alternating currents. Direct currents move electrons through a circuit in one direction, from the negative side to the positive side. In alternating currents, electrons are pushed and pulled, occasionally in opposite directions.
Photovoltaic (PV) solar systems produce an electrical charge called a direct current (DC). Although, the electrical current chosen for the U.S. electrical power grid is an alternating current (AC) because it is less expensive to transmit. So how do we change DC electricity produced by the solar panels into an AC?
A solar inverter is used to convert DC electricity that is produced by the solar system into AC electricity to be used by our homes or businesses. Additionally, inverters provide the solar system’s statistics such as voltage, and energy production. Central inverters are most popular for residential solar systems, although microinverters are used occasionally.
Central inverters currently dominate the inverter industry as they are less expensive and more reliable. Central inverters work by wiring the solar panels together to work as a cohesive unit. While on the other hand, microinverters work by monitoring each individual solar panel. Microinverters allow each solar panel to perform at maximum potential individually, as opposed to performing the system.
When the sun's photons hit a solar panel a direct electrical current is created. The direct current flows into the inverter, which converts it into an alternating electric current. Your home's electric appliances use the alternating current as power. It’s that simple. Although, what happens when you are not home during the day to use your power?
During the day when your home is producing electricity but it is not being used one of two things happen. Either the unused electricity goes into a battery backup system to be used when needed, such as at night. If you do not have a battery backup system, the unused electricity goes back into the grid and is used to power other homes, this is net energy metering or NEM. So, depending on how much energy you use or sell to the grid you could end up with a charge or a credit at the end of the month.
For more information on NEM click here.