How Do Solar Panels Work on a Roof?

Every hour and a half, enough sunlight hits the earth’s surface to power the entire world for a year.

The naysayers would have you believe that solar is an unreliable and expensive technology.

However, solar is clean, green energy. It’s a cheaper alternative to oil and gas, and the technology is well within the budget of the average consumer.

But how do solar panels work? 

The science behind it is fascinating, and this seemingly magical technology operates on very simple principles.

How Do Solar Panels Work?

How do solar panels work? Do they really take the light out of the air and convert it into electricity?

First, it’s important to understand what light is.

Light is electromagnetic radiation. This isn’t the sort of radiation you find in the fuel rods that power nuclear power plants.

Electromagnetic radiation is all around you. Electromagnetic radiation includes radio waves, x-rays, and microwaves! So on the same spectrum that allows you to see this beautiful world, there’s the energy that cooks your food and checks your bones for fractures.

So What Is Light, Exactly?

The name should give you a hint as to what kind of energy this is: electro + magnetic. Electromagnetic radiation is a form of magnetic “electricity” that passes through the air. As such, this radiation is packed with energy that can be used in various forms, such as solar panels for roofs.

To create electromagnetic radiation, you need a charged atomic particle like an electron. Then you take an electric field and accelerate this electron. The movement causes the electron to oscillate.

Electromagnetic Radiation: It’s All About Waves

Electromagnetic radiation moves in waves. These waves have characteristics that determine what kind of radiation they are, such as wavelength, frequency, and energy. Visible light travels in wavelengths that you can perceive with your eyes.

Light is essential to our planet. It not only keeps us warm, but it is also responsible for weather patterns and helps plants to photosynthesize (an organic form of solar energy!) so that the cycle of life can continue. 

Light is made up of photons. Plants capture these photons and convert them into energy. Solar panels are, in a sense, a mechanical plant converting this light energy into electricity.

That’s why solar is touted as the energy of the future. It’s renewable. As long as the sun continues to burn (about 5 billion years are left before it runs out of hydrogen) then solar will be the ultimate solution for future energy.

Different Types of Solar Panels

There are two main types of solar energy, both of which work by entirely different technology. The most common is photovoltaic, also known as PV. The less common of the two is concentrating solar-thermal power, also known as CSP.

Photovoltaic Cells: The Solar-To-Energy Converter

While these light rays may be chock-full of energy, you need a way to capture it. Photovoltaic cells capture light waves and produce electricity as a byproduct.

A photovoltaic cell is made up of two semiconductors which you sandwich together with a space between. You normally make these semiconductors out of silicon. That’s right, the same material they use to make the transistors in computers and phones is the one they use to make solar panels.

Once you dope these semiconductors with different chemicals, it changes their charge. For a solar cell to function, you need to have a positive and a negative semiconductor. Typically, phosphorus is used for the positive side (since it is electron-dense) and boron is used for the positive side (it has very few electrons and produces a positive charge).

You need to create an electric field of opposing sides. Without that, you won’t be able to capture the electrons and push them down the cable to use as electricity.

How Photovoltaic Cells Create Electricity

Now you put those semiconductors under the light. When the photons travel through the material, they knock electrons free from the negative side. When you gather up enough electrons in the space between, they turn into a stream of electricity. 

In essence, you make solar energy by breaking up atoms! But not to worry, this isn’t going to split an atom the way an atomic bomb does. All your solar cells are doing is stealing extra electrons from atoms to produce electricity.

After all this is done, you only need some metal conductive plates to collect the electrons and transfer them to a wire. After that point, the electricity is yours to use however you please.

Concentrating Solar-Thermal Power: Less Common, Still Great

This solar option tends to be used in large plants, not as solar panels for roofs. It works by concentrating the sun’s energy via mirrors, using that heat to drive turbines and produce electricity. 

How Much Energy Can Solar Panels Create?

So now you want some roof solar panels, but you’re curious. How much of that solar radiation can your solar panels convert to electricity?

Photovoltaics have up to 22% efficiency, an impressive amount considering you are essentially harnessing invisible energy.

Bear in mind that solar panel technology has been around for less than 100 years. We’ve made leaps and bounds in efficiency since then. Scientists are hard at work getting that efficiency as close to 100% as we possibly can.

Solar Panels Are an Improving Technology

Solar panels have improved in other ways: they’re cheaper than ever to produce, they can be ultrathin, they can be flexible, and they’re weatherproof. 

Given that solar energy is one of the most efficient and cheap green energies, governments and companies are devoting significant resources to make this one of the dominant energy alternatives to dirty fossil fuels.

Solar is more affordable for the average person than ever before. Choosing which financing option is best for you can help to fit your conversion to solar into a budget.

But What Do You Do When the Sun Isn’t Shining?

A common criticism of solar panels is that when nighttime comes, they can’t produce any energy. While this is true, solar panels produce excess energy throughout the day. Finding a place to store that energy is the solution to solar’s intermittency.

Fortunately, batteries are also a technology that has exploded in recent years. Batteries used to be quite expensive to produce, but the price has dropped by a shocking 97% in the past three decades.

Improvement in Battery Technology

Batteries have larger and longer capacities than their counterparts from just a decade ago. They can quick-charge, and algorithms make sure their charging cycles don’t damage them in the long run.

The advancement in rechargeable batteries has allowed electric vehicles to become a viable everyday option. In the same vein, batteries now allow solar to be a plausible all-day energy source.

There’s no longer an excuse to ignore the benefits of solar if the solution to its greatest weakness has already been solved.

Some solar users may not want to invest in batteries at all, instead using that extra solar energy during the day to cool their house down as much as possible. You can turn your house into a “battery” of sorts. That way you’re taking advantage of electricity when it’s at its most plentiful, rather than cranking up the cooling at night when your solar panels are no longer producing electricity.

Since solar panels for houses are often selling energy back to the grid, investing in solar batteries may actually be a worthwhile solution for you. If you live in a place with a lot of sunlight and very little weather interruption, you may be saving up enough energy during daylight hours to offset your usage in the nighttime hours.

Solar Is Scalable 

Solar is adaptable to whatever circumstances you put it in. Solar can be the energy source that powers entire cities, or it can be mounted on a backpack to charge your phone while you hike. 

This simple fact means that you only need to determine how many solar panels will suit your use case. Many businesses choose only to cover one side of their roof in solar panels, while others use an array that covers every inch.

As a homeowner, you may have a higher energy use than others. As mentioned above, you may live in an area with constant, uninterrupted sunlight. It’s up to you whether you go all out, or only install solar panels on one side of your house.

Solar Is for You?

How do solar panels work? Now you know.

Solar is not some sci-fi technology that’s only accessible to the rich, it’s available for the average consumer. It’s time for our world to move away from burning dirty fossil fuels and produce energy that is clean and near limitless.

Follow our blog for more tips on how to live an energy-efficient life.