Solar panels are the most recognizable component of a residential solar electric system. The solar panels are installed on the roof of a home to collect sunlight and convert the sunlight into electricity. Homeowners install residential solar electric systems to save on electric costs and lessen their environmental impact.
Each solar panel is a collection of solar cells. Solar cells are the component of a solar panel that converts sunlight into electricity.
The solar cells produce electricity by the photovoltaic effect. The photovoltaic effect is produced when sunlight is absorbed by a semiconducting material, such as silicon, and the sunlight separates electrons from their atoms. These electrons travel into a circuit in the solar cell to form a direct (DC) electrical current.
Home based solar panels, also called photovoltaic panels, produce from 10 to 300 watts per panel. To produce a useful quantity of electricity, solar panels are combined to create solar arrays.
Because solar panels only produce electricity during the daytime and homes need electricity at night, there is a mismatch between electricity production and the demands of the home. To overcome this mismatch, systems frequently have batteries to store the excess electricity. The batteries power the home when the panels are not producing.
Batteries can be expensive and have maintenance and disposal issues. As an alternative to storing the excess produced during the day, some systems are configured to transfer the excess production to the local power utility’s system. In exchange, the power utility gives the homeowner credits that are used to purchase electricity when the solar system is not producing. This exchange of credits for electricity is called net metering.
Solar panels and batteries produce direct (DC) electric current. Household appliances use a type of electric current called alternating (AC) current. A device called an inverter converts the DC current produced by the solar panels and batteries to the AC current required by appliances.
Wiring, grounding and over-current protection complete the major components of a household system.
Installation of a residential solar electric system requires expertise in wiring, electricity, carpentry and solar electric products. Homeowners interested in installing a residential solar electric system can benefit by talking to an expert. To find an expert in your area, see our Directory of Installers.
by Bob LoCicero.