How Does Solar Electricity Work?

Solar Electric (PV) Systems

The following is a simple description of the basics of a solar electric, or “PV” system. Solar electricity is generated by a method known as photovoltaics, or PV, for short. It does this by converting solar radiation into electricity by the use of semiconductors that have been made to produce this photovoltaic effect of conversion. 

Typical materials used to make these semiconductors are of various types of silicon for widely-used panels of monocrystalline or polycrystalline solar cell construction, or more exotic mixtures that are based on either cadmium telluride (CdTe) or copper indium gallium selenide (CIGS), for what are called thin-film solar cells.  These materials are formed into the individual solar cells which are then linked together to form a single solar panel, module or other shapes such as flexible rolls, and even building materials like shingles and siding.  Either a single solar panel may be used to produce electricity, or several of them may be strung together as part of a solar array to form the basis of a greater-producing solar electric system

Since the electricity produced by a solar cell is direct current (DC) form, and the vast majority of appliances and electrical devices are run on alternating current (AC), this PV power must be changed into AC form before it can be used. This is done by directing the current coming from the solar panels to a power inverter. From there it will then be run to one of the two next possible points in your PV system: a battery bank, or to the mains power panel for the home, which in turn is connected to the electric utility grid. These are 2 distinctly different ways of handling your PV power. Those who store their power in a system of batteries are generally not connected to the grid, and rely solely on the power from those batteries to provide for their electricity. Batteries themselves hold electricity in DC form, so the inverter will then be situateddownstream of the batteries, where after it has been inverted to AC form the household may then use the power without harm to its connected appliances and devices.

Those who remain grid-connected (or “grid tied”) do not need to store their PV power, but rather have it “tied” to the utility system by simply having it connected to the power main, where it off-sets their actual use of utility-supplied power by however much PV power they may have produced. In most cases the owner has PV production that is providing somewhat less than the total that they need over the course, say, of a given month. There may be times however during any given day that a PV system produces more than the house is using at that very time. When this occurs, the system is net producing electricity and essentially “spinning the meter backward”. This is managed and recorded by means of a utility-installed bi-directional meter that tracks the electricity as it moves in either direction --- from the utility to the home, and vice versa. The owner is credited for their power production supplied to the grid, and/or is simply “net produced” within a specific period of time, the rates paid or credited to the customer for such being specifically agreed to between them. These are generically termed as net metering agreements and they specifically state the terms of rates that a utility will pay, or credit, to the customer for any net electricity production that their PV system provides, or “puts up on the grid”.                                         
Solar Electric (PV) systems can be used both residentially and commercially