The Science Behind How Solar Panels Generate Power

It’s impossible to deny that solar is only growing more and more popular among homeowners, from large solar panel installations on homes to portable solar generators that allow you to transform sunlight into energy no matter where you are. However, one thing that not everyone is entirely clear about is how exactly solar panels generate power.

Luckily, the process of how solar panels generate power is not all that complicated once you understand some basics.

In this article, we’ll look at the different parts of your solar panels, as well as how those parts work together to convert sunlight into renewable energy. We’ll also look at how solar energy helps you lower your utility bills and how you can make sure you’re getting the most performance out of your home’s solar panel systems.

What Are Solar Panels Made Of?

While solar panels may seem complicated, in reality, their construction is a relatively simple layering of a few important elements: silicon wafers, contact grid, coated glass, and an opaque backing.

Silicon Wafers

The most important part of a solar panel is the array of silicon wafers. These wafers are made of two layers of silicon, one negatively charged and the other positively charged. The negative (n-type) silicon layer has an additional electron, while the positive (or p-type) layer is missing an electron.

These two layers make up the photovoltaic (PV) cell. In typical solar modules, many rows of PV cells will be arranged next to each other in a single layer, then connected to a single circuit, which transfers the electricity to the electrical system.

Coated Glass

On top of the PV cells is a layer of tempered glass, which provides a significant amount of strength and rigidity to the solar panel. The glass typically comes with a coating known as an EVA film. This film helps insulate the cells from vibrations and other damage, while also helping protect the solar cells from damage due to excessive ultraviolet (UV) radiation.

Contact Grid

Sandwiched between the glass coating and the solar cells are the contact grids, and these are responsible for transporting power from each individual PV cell to the main power distribution line. These grids are responsible for the distinctive stripes that you may notice on a solar panel.

Opaque Backing

The backing on a solar panel may seem like it’s there mostly to keep all of the pieces together, but in reality, it plays a much more important role. While it does provide additional rigidity, its primary function is to help isolate the solar module from the external environment. This helps the panels keep working at peak efficiency while also preventing electricity from “leaking” out of the panel and potentially causing serious problems to your home.

How Solar Panels Generate Power

Now that you know how residential solar panels are constructed, it’s time to focus on the main question: how solar panels generate power? Whether you choose to have a professional installation or you prefer DIY solar kits, the principles of how a solar panel works remain the same.

1.Sunlight Activates the Panel

Your solar installer will likely group together several solar panels next to each other, creating what is known as a solar array, usually installing them on the rooftop that is likely to see the most sunlight throughout the day.

Sunlight is composed of particles known as photons. As these photons collide with other particles, they transform potential energy into other forms of energy, usually heat. This is why you feel so warm when you stand in the middle of a sunbeam.

However, in a PV system, sunlight hits a solar panel, it has a different effect. The photon excites the electrons in the PV cell, knocking the electrons in the negative layer to come loose and be attracted to the positive layer.

2.Cells Produce Electric Current

Once the sunlight has brought the PV cells to life, the loose electrons begin to move back and forth between the different wafer layers. This continuous transfer is what is responsible for the electrical current in a solar electric system.

Because of the nature of the two layers in a PV wafer, the reaction between sunlight and the electrons continues as long as there is sunlight. The stability of silicon means that the imbalance between the two layers of the wafer never fully resolves, and they continue to pass electrons back and forth.

3.The Electrical Energy Is Converted

The electricity that a solar panel produces is what is known as direct current, or DC. However, almost all homes rely on what is known as alternating current, or AC. In fact, the electricity delivered to homes is almost always in the form of DC (direct current) since it travels over distance more efficiently.

In order to be able to use electricity, it needs to be converted or transformed from DC into AC. Just like electricity in your home passes through a transformer, home solar systems use a string inverter device, sometimes just called an inverter.

Inverters come in two different forms. Some solar power systems have a microinverter attached to each panel, which transforms the electricity as it passes from the panel into your electrical system. However, most systems use a string inverter, which connects to several different panels and transforms the energy all of those panels produce simultaneously.

How Solar Energy Systems Change Your Electrical Usage

No matter how efficient your home solar system is, almost all places require homes to be connected to the main power grid as well, as a safety precaution. Because you can’t control the amount of sunshine that your home will receive, it’s important that you have a source of power that you can rely on if solar does not produce enough for your needs.

Still, solar power has the potential to end up saving you a significant amount of money on your home electric bill.

Your solar panels will only generate electricity when the sun is shining. On cloudy days or at night, you can only consume energy, and you may not have enough spare energy to run your home. On the other hand, your energy production will be highest during the middle of the day—when most people are out of the house and least able to make use of the energy being produced.

This means that the majority of the energy you produce from your home solar system could be lost. However, there are two solutions to this problem: net metering and battery backup.

Net Metering

In net metering, your utility will install a meter that measures the amount of energy you are drawing from the electrical grid and the amount of energy your solar panels produce that you send back into the grid.

In most cases, you’ll end up drawing power from the grid when you don’t have sunlight to produce energy, usually when it’s overcast or during the nighttime hours. During the day, though, you’re likely producing far more energy than you can immediately use. With net metering, that energy is sent back into the grid.

The utility company will send you a bill that calculates how much energy you consumed against how much you contributed back to the grid, then charges you for the balance at the end of the month.

It’s important to note, though, that electricity is usually not billed at the same rate throughout the day. Power consumed during peak hours is often more expensive than the power your home generates during the day at off-peak times. In other words, while you may generate more electricity than you use, you may still end up owing your electric company based on the difference in those rates.

Battery Backup

Another option for dealing with the excess energy your solar panels produce is to invest in storage batteries. As your solar panels generate electricity, any excess charge that isn’t being used is instead used to charge storage batteries. These batteries can then be used to power your home during the hours your panels are not producing electricity.

While battery backup does provide you with more control over how you use your excess energy, there are two things to keep in mind. First, battery storage is not as efficient as sending your excess energy back into the grid, and you likely won’t see the same rate of return based on the amount of electricity you produce.

Second, your battery backup is unlikely to be able to provide you with enough power to be able to avoid using the grid completely. While this method will certainly save you money on your electric bill, it is unlikely that you will be able to avoid using commercially-produced electricity completely.

Maximizing Your Energy Production

Several factors can affect how much energy your solar system will provide over time. Here are four of the most important things to consider regarding solar panel installation and upkeep.

Avoiding Shade

Because solar panels only work when they receive direct sunlight, it’s important to avoid putting panels in areas where they may be shaded. This could be from trees, taller buildings, or a number of other causes. The more sunlight your panels receive, the more efficiently they will work.

Year-Round Sunshine

The amount of sunshine that your solar panels will receive changes based on the season—but not because of temperature. While things like dust, debris, and snow can prevent your solar panels from working effectively, the temperature shouldn’t have much of an impact.

The other thing to consider is the length of the day. During winter, the days get shorter, which means you’ll produce less electricity during the day. The opposite is true during the summer when the longer days mean you’ll be able to create much more power.

What’s Your Angle?

The angle your panels are installed at can significantly impact the efficiency of your solar system. You want your panels to be able to catch as much sun as possible, and that usually means pitching them somewhere between 30 and 45 degrees. A good rule of thumb is to angle your panels to match the latitude they’re mounted at.

North and South

The sun is not directly overhead of all people at all times. In the Southern Hemisphere, the light at noon is angled from the north, which means that to get the most sun exposure in that part of the world, your panels should be facing the north side of your home. While this may seem like a small matter, you would be surprised how much power you might be losing with panels installed facing the wrong way.

What’s the Difference Between Solar PV Panels and Solar Thermal Panels?

It’s worth taking a moment to talk about concentrating solar-thermal panels (CSP), an alternative to PV panel technology. Unlike PV systems, which use sunlight to activate photoreactive cells, CSP systems employ mirrors to direct sunlight in a way that concentrates it. The mirrors send this concentrated sunlight to solar receivers, which collect the energy and store it as heat, where it can be used to produce electricity.

While CSP systems do have some advantages over PV systems, they are generally used only in large solar plants since they rely on large-scale installations to work effectively. For most people, they will be dealing exclusively with a PV system.

Ready for Your Solar Panel Installation?

Now that you know how solar panels generate power, the next step in considering your own solar panel array is determining your needs. Whether you’re installing a system on the roof of your home or you’re considering investing in a portable solar generator, you can use this solar panel calculator to determine how many panels you should install.

Solar power is an excellent way to lower your utility bills while also increasing your reliance on renewable energy sources. As we move into the next several years, solar energy will become more important than ever. The more familiar you are with the technology, the more ready you’ll be to install your own solar panel system.