How Solar Energy Works
A ‘Simple-Language’ But Complete Guide to How Solar Panels Turn Sunlight Into Power
You’re not a scientist. You may have taken chemistry and physics (or maybe you didn’t), but let’s be honest – this solar energy stuff is complicated.
Most articles out there trying to explain solar power end up talking to you at a college level – assuming you know a bunch of science language and concepts that many people actually don’t. And not for lack of trying. One person on our staff used to teach high school chemistry. It’s not easy.
This article will attempt to explain in language simple enough for a sixth grader the basics of how solar energy works.
First, do you have kids? If so, we have a favor to ask
If you have kids somewhere between 4th and 8th grade, ask them to read this article with you. Tell them it explains how solar power works. If they struggle to understand any part of it – email us and let us know where they got stuck, and we will find a different way to explain it.
Ready? Let’s get to it.
Let There Be Light
For solar to work, it begins with sunlight reaching the earth’s surface.
But light isn’t such a simple thing. What’s it actually made of? How does it produce energy? Did you know people as brilliant as Einstein have puzzled over these questions?
And in fact, it is Einstein’s theory about light that we apply today to make solar power work. But to understand his theory, you first need a basic understanding of atoms.
Atoms? What Are Atoms?
They’re the basic building blocks of everything you see. Whether it’s your couch, your chicken soup, the air, or your fingernails, everything is made of tiny particles called atoms.
How tiny? Smaller than you can see with a microscope. You can see the cells of your body and of plants with a microscope. But atoms are several thousand times smaller than cells. They’re so tiny, that billions of them make up the small pieces of your fingernails that you clip off.
There are only about 100 different types of atoms. Stop and think about that for a second. Everything you see, smell, taste, and touch – in the universe – is made up of some combination of just 100 different types of atoms. Pretty amazing.
Each type of atom makes a different element, and the elements are found on the periodic table.
Here’s a periodic table. You’ll recognize a lot of these, like oxygen, gold, aluminum, and sodium. Others you’ve probably never heard of.
Silicon is circled, because for most solar panels used today, silicon is the element we use (though there are some new technologies emerging).
Each element is made of atoms of different weights. So, oxygen atoms weigh less than sodium atoms, which weigh less than silicon atoms. The periodic table is in order of increasing weight as you read it left to right. Hydrogen is the lightest.
What makes the weights different?
This depends on the number of protons, neutrons, and electrons – even tinier particles that make up the atoms. The protons and neutrons are in the nucleus in the center. The electrons fly around the outside.
Here’s a basic model you may have seen before:
Electrons: The Key to Solar Power
For solar power, the key is the electrons. And that brings us back to Einstein and the question of light.
Light travels in waves, not in straight lines. And even though it doesn’t weigh anything, it still has energy. When light hits a surface, this “solar energy” can cause electrons to escape from their atoms. That means the electron no longer flies around the nucleus, but is free.
Einstein called this the “photoelectric effect.” (We promise, that’s the only big word in this article).
So when sunlight hits the silicon crystals in a solar panel, it releases electrons. Once free, those electrons can travel anywhere within the crystal array.
Electric Current – The Movement of Electrons
What is electricity? It’s simply the movement of free electrons. “Current,” a word we see all the time when talking about solar power, is how we measure this movement.
Current: The flow of electrons measured over time. An “ampere,” or amp, measures electrons per second.
The free electrons in the silicon solar panels are now moving, and they have a current. When solar panels are created, the manufacturers insert wires throughout the panels to capture as many of these moving electrons as possible.
Why? Because electrons move more easily over wires than just random surfaces. So the wires allow us to capture more of them to use their current as energy.
Those wires send the current down to the power supply area where it gets turned into solar power.
Still with us? If you’ve gotten this far – you’ve got the basics down.
But how does the electric current from solar panels actually power your house?