What Are Solar Panels? - Photovoltaic Solar Cells and Solar Thermal Electric Generation

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Solar Energy: Understanding Active and Passive Solar Heating

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:05 The Sun
  • 0:46 Photovoltaic Solar Cells
  • 2:06 Solar Panels
  • 3:22 Solar Thermal Energy
  • 5:00 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed Audio mode
Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

How do devices take advantage of the sun's abundant energy? Learn about photovoltaic solar cells and solar thermal electric generation and how these technologies can be used to convert solar energy into heat and electricity.

The Sun

The sun is a hot ball of gas that generates enough energy in just one hour to easily meet the energy needs of planet Earth for an entire year. The challenge is how to harness all of that energy. So, the problem that man faces is not a lack of energy; it's a lack of ways to capture the existing energy from the sun, and efficiently convert it into usable energy that can heat our homes and provide electricity. So, I guess you could argue that we don't have an energy problem here on Earth, we have a conversion problem. In this lesson, we will take a look at some of the technology man has developed to capture what the sun has to offer.

Photovoltaic Solar Cells

Solar energy is energy obtained from the sun, so if you think about the sun's rays, you will notice that they are spread out. In order to use the energy from the sun, we need ways to collect and absorb solar energy. For this, we use solar collectors. You may not realize it, but you are probably using solar collectors every day. For example, there is a good chance that calculator lying on your desk is run by solar energy.

Small devices, like calculators, require only a few watts of power, and they can generate this power without the need of batteries, using just a few photovoltaic solar cells. These small cells are often referred to as simply 'photovoltaic cells' or 'solar cells,' and they are devices that directly convert light from the sun into electricity. So, as long as there is light, these little cells seem to power your calculator forever. You can recall the term 'photovoltaic' by remembering that the word 'photo' refers to light, and the word 'volt' is a unit of electric potential. Therefore, a photovoltaic cell converts light to electricity.

Solar Panels

If photovoltaic cells are connected together, you have a solar panel. You have likely seen solar panels on rooftops of homes or businesses, but they can also exist as large arrays on open fields and can even be found powering satellites out in space. Photovoltaic cells use thin layers of a semi-conducting material called silicon. Silicon is an element, and you can find it on the periodic table along with all of the other elements. It is also what makes up sand.

When light particles hit the photovoltaic cells in a solar panel, electrons in the silicon atom dislodge and bounce around, which starts a chain reaction. These electrons dislodge and move, one after another in a continuous flow, providing an electric current that can be used to power homes and workplaces.

We learned that photovoltaic cells directly convert the sun's light into electricity. So what happens when the sun is not shining? Unfortunately, when there's no light, solar panels cannot generate electricity. Therefore, some type of battery or back-up energy system is needed to use this energy at night or during cloudy days.

Solar Thermal Energy

We also use solar thermal energy to collect solar energy. Solar thermal technology creates electricity indirectly, as opposed to photovoltaic technology that directly creates electricity from light. Solar thermal energy collects the sun's light, which heats a fluid, such as water; the resulting steam is used to run a generator that makes electricity.

You can recall this term by remembering that the word 'thermal' refers to heat. Essentially, solar thermal energy works as a giant water heater, and this form of solar technology is primarily found in very warm places where the sun is reliable.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account