Did you ever wonder how solar panels turn sunlight into energy? It’s simpler to explain than you might think.
Solar photovoltaic panels are the type of solar panels that make electricity. We’ll be discussing that kind of panel today. (The other kind, solar thermal panels, turn sunlight directly into heat. They work a little differently, but that’s a subject for another article.)
How Solar Cells Work
The critical portion of a solar electric panel is the silicon wafer. Silicon in its crystal form is a semiconductor. A semiconductor is a material that will conduct an electric current, but only partly. This may not sound very useful. However, when they are “doped,” or treated, with special chemicals, semiconductors will gain a positive or negative charge. This makes them very useful for creating an electric current.
A solar cell (the smallest unit within a solar panel) consists of two very thin layers of treated silicon wafer. One has been given a positive charge and the other a negative charge. This creates an electrical field near the top of the cell where they meet.
When photons of sunlight hit this electrical field, the negatively charged silicon layer absorbs them and releases negative particles (electrons). The electrons are attracted toward the positively charged layer. When you connect the layers to an external load (like a light bulb), the voltage differential between them causes electric current to flow.
Making Solar Energy Work for Your Home
A single solar cell only produces a watt or two of electricity. To create enough power to be useful, they have to be combined with many other cells. Individual solar cells are bundled together into modules — the multi-cell squares that you see when you look at a solar panel — and then framed up into a panel. From there, multiple panels may be strung together in an array to produce sufficient energy to power your home.
Solar panels produce direct current (DC) electricity. For household use, it has to be converted to alternating current (AC) power. That is done by adding a component called an inverter to the system.
Why Solar Energy Rocks
Some solar naysayers claim that solar panels don’t produce enough energy to make up for the energy it takes to produce them. This is a proven myth. Solar panel energy payback is typically four years or less. You can expect them to last at least 25 years, but many last much longer. Clearly, solar panels return far more energy than they consume in manufacturing and distribution. They also consume considerably less water than coal, oil or nuclear.
Once installed, solar panels are extremely reliable. They have no moving parts and require minimal maintenance. They emit no carbon or other pollution while operating. They are as quiet as it gets, and solar energy is becoming increasingly affordable. No wonder many experts predict that solar will become the world’s main energy source by mid-century!