Converting Photons to Electrons: The Science That Is Solar Energy

BY contributor | Mon May 13, 2013

You’ve seen solar panels on houses, and you’ve heard about them in the news. You may even have read up on them a little bit. You know that solar panels convert sunlight into energy, helping to power your home. However, do you really know how they work?

The Basics

Generally, the solar cells you are going to see are photovoltaic cells, also known as PV cells. Photo means light, and voltaic means electricity, which allows us to see where the name solar energy comes from. These PV cells convert sunlight into electricity allowing you to light your home, power your electronics, and more. Normally, they are connected together into a group, and then put into a frame. This is what makes up the solar panels we see on a regular basis.

So, What Happens?

Each cell has a variety of material, including semiconductors. Currently, the most commonly used is silicon. The silicon absorbs the energy of the light that hits it. Because of the energy, the electrons get loosened, and they are then able to flow. With strategic placing of magnets on the solar panels, the electron flow is directed and power is produced.

Why do we use Silicone?

There are many different reasons silicon is currently used for solar panels. One is because it is a great semiconductor. Another is because of the great properties it has while still in crystalline form. The atom is made up of three shells, each of which holds a part of its 14 electrons. The first shell holds two electrons, the second shell holds eight electrons, and the third shell only holds four electrons. However, the atom is constantly trying to fill that last shell to maximum, by attaching to other electrons.

Generally, it is not pure silicon that is used, but an impure mixture of silicon and phosphorous. This creates an effect where the shell is filled, and since the phosphorous has five electrons, instead of four, there is only one left over. When energy is added to the impure silicon, the extra electron can be easily knocked loose from the structure, allowing a large number of free carriers to power the cell.

How Efficient Are Solar Panels?

Once the panels have been created, and had an antireflective coating added, as well as a glass cover plate, they can be used in a variety of ways. One great way a solar panel can be used is on the roof of your home. The question becomes, how effective are these panels? In 2006, almost all panels had an efficiency rate between 12-18%. The best option in that same year had a 40.7% efficiency rating. For many people, this seems extremely low. So, why is there such a low efficiency when tapping into the energy of the sun?

Many Ways to Lose Energy

There are a variety of ways that energy can be lost. Unfortunately, these are unavoidable. For example, we know that light comes in a variety of wavelengths. We have found out, since working with the solar panel technology that some of these wavelengths have too much energy for us to trap, while others don’t have nearly enough. This is defined by the material used for the cells, and we can use materials that have a broader range. However, if we do that, we lose a lot of the voltage of the panel.

In addition to the losses that happen because of the wavelength, there are also losses in energy due to the makeup of the cell itself. Since a semiconductor is used, in this case silicon, there is going to be some resistance against the current. This resistance is going to cause some loss of energy, even though the current is helped along with metallic contacts.

Power Concerns for Those Using Solar

If you have added solar panels to your home, or are considering taking the plunge, there are some concerns that have probably crossed your mind. The most prevalent being that it’s not always sunny. What can you do if there’s not enough sunlight to go around? Luckily, there are some options for those in this predicament.

  • Have a backup generator that will kick in when the solar panels don’t have enough power to do it all.
  • Connect to the utility grid. This also allows you to sell power back to the grid when your panels produce more than you are able to use.
  • Get a battery. This will help you store the power that you produce in your own home. It will allow you to draw on this power in the future when you need it.

Each of these options has definite pros and cons to them, and it all comes down to personal preference. If you are trying to go completely off the grid, and not rely on the power company at all, a generator or battery is what you will need. However, the stability of working with the power company is a benefit for many. This is a very personal decision, and should be made after doing some research on each of the options available.

What Are the Advantages of Solar Energy?

Because of the lost energy, the question becomes whether or not solar energy is worth what we are putting into it. For many, it is a resounding yes. Not only is this something that is a great scientific find, it is also an amazing option for anyone who is looking to cut down their carbon footprint and live a greener lifestyle. There are, of course, downsides to solar energy. However, there are downsides to everything we do. If one of the worst things that can be said about the technology is that right now we are only at, at max, 40% efficiency that simply means we have more work to do to make it better.

Understanding solar energy can be a little difficult sometimes. There is a lot that goes into it. When considering solar energy, it is important to understand the basics of what goes into it.


About the AuthorShaun Chatman is a well published author on many authority sites. He lives in Dunedin, FL, and spends his free time playing with his kids or advising friends on tech, gadgets, travel and finance

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