Adding rooftop solar panels is one of the fastest growing home improvement projects. They deliver thousands of dollars in savings by converting FREE sunshine into valuable electricity. So, how do solar panels actually work?
Solar panels: A solar panel is made up of several photovoltaic cells (photo = light and voltaic = electricity) that are assembled under a single glass sheet. Solar photovoltaic cells react to light by freeing electrons that are then channeled and collected, forming electricity.
Usually, multiple solar panels are connected in series to generate more power. Bigger installations will require multiple strings that are connected to a combiner box which pools the electricity from the different strings. The electricity that is produced by solar panels is DC (Direct Current) electricity. However, most home appliances use AC (Alternating Current) electricity, so inverters are used to convert DC electricity to AC electricity.
Inverters: Inverters convert DC electricity to AC electricity. Two types of inverters are typically used in home solar power systems - string inverters and microinverters. With string inverters, all the DC electricity generated by the panels is aggregated in strings before being converted into AC electricity by the string inverter. With microinverters, each solar panel has a microinverter that converts DC electricity to AC electricity. The AC electricity is then aggregated across multiple solar panels and strings.
Net Metering: The AC electricity produced by a solar power system can be consumed by appliances in your home just like they consume grid power. When the solar power system produces more electricity than is required (e.g., during weekdays when consumption is lower), the excess electricity can be sent to the grid. Likewise, when your home requires more electricity than is produced by the solar power system (e.g, at night), the grid supplies the additional electricity that is required.
Net Metering is a mechanism wherein the excess electricity sent to the grid is credited by the utility at the same rate as the electricity that is consumed from the grid. In other words, this is like your electricity meter running backwards when you are producing excess electricity and feeding it into the grid. Net Metering allows homeowners not to worry about exactly matching the electricity usage to solar electricity production.