Every single hour, the sun pours 430 quintillion Joules of energy onto the earth. That’s enough energy to power our blenders, cars, airplanes, air conditioning, and every other human energy need for an entire year! It seems like we should be able to find a way to harness all that sunlight, right? Well, that’s exactly what solar panels are designed to do.
If you’ve considered installing a solar power system on your home, you probably want to know how thin panels on a roof can charge your electric car or keep your home nice and cool during a particularly hot California summer.
Below, we’ll dive into the science of solar energy.
Don’t worry, you won’t need a chemistry degree to keep up. We’ll break down the process step-by-step and make it easy to understand how solar power for your home is possible.
The central challenge in using the sun to power homes and cities is figuring out how to turn sunlight into a power source we can actually use.
In a nutshell, solar panels work by turning photons from the sun into electrical energy. Unfortunately though, you can’t use photons to power your cell phone or keep the lights on at night until it is turned into electricity.
And the conversion process starts with a special substance called silicon, a crystalline element with strong semi-conductive properties.
While other semiconductor materials can be used, the vast majority of solar panels are made of silicon, because it is one of the most common elements on the planet and is therefore easier to access (and less expensive) than other options.
For each panel of photovoltaic cells, there is silicon sandwiched between the conductive layers. Here’s where the process gets a little sciencey, because each layer is slightly modified.
The top layer is changed so that it holds a negative charge, while the bottom layer is turned into a positive charge. The attraction of these two layers (negative and positive charges are drawn to each other) creates a powerful electric field, which is a key ingredient in the solar panel recipe.
Next, it’s time for a quick chemistry lesson and then lots of sunshine.
Like every element on earth, silicon is made up of numerous tiny atoms. An atom contains a stable nucleus of neutrons and protons surrounded by zipping electrons. For our purposes, we’ll just focus on those electrons.
Electrons have a negative charge and are drawn to the positive charge of protons. This bond isn’t unbreakable, though. In fact, electrons can be stolen by other elements or knocked out of their atoms by an intruder.
This is exactly what happens when photons come pouring down on a rooftop solar system during a sunny day. Those little photons knock electrons out of their orbits, and the electric field kicks them out of the silicon field junction altogether.
Don’t worry, these little guys aren’t lost, though. They just need to take the long way round.
After electrons are booted from the silicon field, they’re captured by an external circuit. The electrons flow down the circuit, and this is what creates electricity. Eventually, the electrons return to the solar cell where they align back into the orbit of a silicon atom that needs an electron.
In this way, nothing is lost or used up - like when fossil fuels are burned to create electricity.
In fact, a solar panel system is completely self-contained and helps many people create self-sustaining homes in California.
The power created by that journeying electron we just mentioned isn’t quite ready to go right down into your electric socket and power on your stove in the morning.
One more conversion has to happen.
Solar panels turn photons into a special type of current called a direct current (DC), but here in the United States, our electrical grid runs on an alternating current (AC).
This means that no solar power system is complete without a special device called a inverter. Despite its name, an inverter doesn’t turn DC into AC. Rather, the direct current powers the creation of the alternating current, which can then be used to power a home.
The final destination for your alternating current will depend on the setup of your solar power system.
Most homeowners in San Diego and other parts of California are part of the net metering system, which means that the excess electricity produced by their solar panels goes into the public utility grid. If you have this system, your electricity meter will actually tick backwards when your system produces more electricity than you can use.
At night or on cloudy days when you need to use more electricity than the solar panels on your home can produce, the system will automatically pull electricity from the grid and your meter will go forward. A well-designed solar power system should balance out each month, producing the amount of electricity you need so that your electric bill is low, non-existent, or even shows a net gain.
The other option is to install a solar battery in your home that can collect the excess electricity your system produces. At night or on cloudy days, you can power your house from the battery. Battery technology continues to improve, and it might be the right option for those who live off the grid or who want to be as self-sufficient as possible.
Now that you have a basic understanding of how solar panels work, remember that a single photovoltaic cell can only produce a little bit of energy. It might create enough to charge your cell phone, but not nearly the amount you need to keep your home humming - which is why each solar panel is made up of many photovoltaic cells, and panels are combined to create a complete solar power system.
Several factors go into determining exactly how many solar panels you will need for your home, such as the size of your roof, your electricity needs and the amount of sunlight your home receives throughout the year.
That’s why we always recommend getting a complete energy analysis and onsite evaluation.
At Semper Solaris, we believe it’s important to make sure you have a solar power solution that fits your needs, which is why our evaluation is free.
We want you to understand exactly what you’re paying for and how your new investment works, so don’t hesitate to call or email us with your questions!
