Solar panels are large, dark-colored panels of glass and metal, usually aluminum. And yet despite their remarkably simple appearance, these devices can turn sunlight into clean, renewable, and reliable electricity that can actually power your home. How does this work? Well, the science is actually simpler than you might think. In this blog, we’ll break it down into simple terms that will help you understand a little more about what those square panes on your roof are actually doing.
Electricity at its core is a flow of electrons. Think of it kind of like water flowing through a hose or down a river: you can have different speeds and different amounts of water moving through different-sized channels, but water still flows. When you put a water wheel into a river, the river turns it, converting the river’s energy into work. In electricity’s case, the electrons are like the water, and solar panels are what cause them to move and flow like a river, creating energy that your home can then use to perform work.
In order to do this, your solar panels are composed of small devices called photovoltaic cells. Each cell is essentially a sandwich composed of two layers of a semi-conductive material, usually silicon, with each layer being coated with a different substance to try to polarize it or give it a positive or negative charge. It’s this difference in charge that creates an electric field and allows solar cells to create electricity. The top layer is usually coated with phosphorous, which gives it a negative charge by adding extra electrons, and the bottom layer gets a coating of boron, which gives the layer a positive charge by removing extra electrons.
In the negatively-charged phosphorous side of the silicon sandwich, the electrons are stuck in a particularly rigid structure due to their high concentration. Conversely, on the positive side, the lower electron count means the electrons are freer to move about because there is more space between them. When an electron is removed from the negative side, it creates a positively charged “hole”, which is then filled by a negatively-charged electron from the positive side.
How does this happen? When sunlight strikes the cell, the photons, or light particles that compose sunlight, collide with the cell. This knocks the electrons in the negative side free from their structure, creating a positively-charged hole that is then filled in. The electric field at the junction between the positive and negative sides of the cell causes the electrons and “holes” to move in only one way, thus allowing for a stable flow of electrons in only one direction. The now-free electron then moves towards a metal plate alongside a cell where it is transferred to wires and can flow like any other source of electricity. It’s this flow that’s then sent to your home and powers your devices and appliances.
Of course, this isn’t a one-way trip. Once the electron has been used to produce energy, it’s then sent back to the solar cell through the return wire (after all, electricity can’t flow without a complete circuit). The return wire is connected to a sheet of conductive aluminum on the back of the cell, which then allows the electrons to return to the positively-charged side of the cell, and the process starts over.
This is what makes solar such a key technology: no actual physical matter is burned or consumed in order to create electricity. The sun propels photons to earth, and the sheer force and energy of the photons colliding with the negatively-charged layer are what causes the electrons to come loose and perform electrical work. In theory, perfect materials that never degraded over time could theoretically produce electricity as long as the sun burns bright in our sky!
In spite of the engineering ingenuity built into a photovoltaic energy system, the process of converting the sun's rays into usable energy is a relatively simple concept.
Switching to solar power is not only a great way to save money on your energy bills, it is also a green energy alternative that is good for the planet. If you're interested in learning more about solar energy and would like information on installing solar panels on your home, we invite you to give us a call today. Our San Diego solar panel installation team would be happy to provide a free in-home consultation to give you the knowledge you need to go solar!
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