Solar Panel Efficiency And What it Means For Your Future!
How Efficient Are Solar Panels?
So you have finally made the decision to install solar panels. Congratulations! Now comes the hardest part: proving all the naysayers wrong. There’s a lot of speculation around the actual benefits of solar panels. Most of the information out there is wrong, insufficient, and quite frankly, a bit ignorant. Still, the largest concern comes from those questioning the efficiency of panels, which begs the question:
How Efficient Are Solar Panels? The average solar panel works at an efficiency of between 16% and 21%. However, a panel’s efficiency is determined by several things, including environmental factors, the materials that comprise the panels, and solar reflectance.
Some highly efficient panels, under ideal circumstances, can reach levels up to 23% to 25% efficiency. Read below to find out more about the various factors, both long term and short term, that determine the productivity of solar panels and find out what you should expect from your panels.
Solar Panel Efficiency
The silicon solar cells that we use today were first invented in 1954 by three scientists working at Bell Labs. Before the use of silicon, solar cells made in the 1800s had a less than 1% efficiency. Not exactly ideal. Over the years solar panels became increasingly more productive, in fact, the National Renewable Energy Laboratory (NREL) actually created a solar cell with 47.1% efficiency. Of course, this was one under concentrated illumination and in a laboratory setting but it just goes to show the unlimited potential of solar.
Still, this begs the question of why do most silicon cell solar panels have a productivity level of around 20 percent? To understand this let’s quickly look at how a solar panel actually works and what factors impact efficiency.
How Do Solar Panels Work?
Solar panels are composed of cells that use either monocrystalline or polycrystalline silicon cells. When the sun’s rays hit the panels, solar radiation is absorbed which causes electrons in the cells to get excited and rapidly move around creating an electric current.
This direct current is then transformed into a usable active current, or electricity, by a solar inverter. So a panel’s efficiency is a measure of how much of the sun’s energy it can convert into usable electricity. Simply put, if a panel has 15% productivity, then it is only able to convert 15% of the sun’s rays hitting the panel into electricity.
So now why can’t solar panels be 100% efficient? Why the large gap? Well, the basic answer is Carnot’s Theorem, which specifies that no heat engine can obtain 100% efficiency. As it relates to solar, this principle applies as does the fact that the solar spectrum puts out photons at a broad range, and not all can be absorbed by solar cells. Theoretically, with maximum absorption, we are looking at around 68% efficiency. Of course, these ideal conditions have never been reached.
Feeling bummed out? Don’t be! The 20% efficiency that panels reach today is more than enough to power your home, city, and even the entire world. Take that, haters!
Now let’s take a look at the factors that affect the productivity of panels and what you can do to get the most out of your installment.
Factors That Impact Solar Panel Efficiency
There are a number of external and internal factors that can dramatically impact the efficiency of solar output, so let’s take a look at some of the most common ones. It should be noted also that quality really wins points here and the better the panels the better the quality. That’s why at KNS Solar we pride ourselves on having Tier 1 panels which are highly efficient and long-lasting!
The external factors and extreme environmental conditions are really what hurt your panels’ efficiency the most. Things like rain, snow, cloudy weather, wind, dust, hail, and ice all impact panels. A lot of these seem obvious, if you have clouds blocking the sun or snow on top of your panels you really aren’t going to be hitting those double-digit efficiency numbers.
Still, sometimes things like UV degradation and thermal cycling can also have an impact on your panels. These processes can cause discoloration of your solar cells and lead to faulty panels. That’s why you really should consider getting quality panels that are sure to last 20, 25, and even 30 years!
Within the context of environmental factors, you also have to consider things like trees that may cast a shade on your panels and the angle or degree of your panel towards the sun. Again you should consider going with an experienced installer that will take all of this into account and make sure you get the most out of your panels. Luckily at KNS, we got you covered!
2. Materials Used (Monocrystalline vs. Polycrystalline)
This is one of the most significant factors that impact solar efficiency. Solar panels are made up of silicon cells and while silicon is one the most abundant resources on earth, the crystals used in solar panels are actually very rare and expensive. Solar panels made of Monocrystalline are more efficient as they have a uniform composition because they are cut from a single source of silicon, unlike polycrystalline cells which are composed of a number of silicon crystals giving them a more fragmented configuration after being melted together.
Light is reflected off of surfaces and the more that is reflected the less is actually absorbed. That’s why black colored clothes get so hot under the sun because they absorb a lot of light and reflect very little, which is also why they appear black and not brighter. Similarly, panels that are made to reflect less light are dramatically more efficient.
This is why glass is such an important part of a panel as it reflects very little. You can also make sure you buy quality panels with a good coating of anti-reflecting materials.
4. Treatment and Care
One of the most important aspects of maintaining high-efficiency solar panels over the long-term is making sure you take good care of your panels. You should take time throughout the year to clean your panels from leaves, dust, and even bird droppings. Just be careful when you go up there.
You may also need to perform some rudimentary maintenance. If you don’t know how (or just don’t want to do it yourself ) contact us today and we can discuss a maintenance schedule for your home!
There you have it! There are a number of other factors that may impact the productivity and efficiency of your solar panels. For the most part, if you rely on high-quality panels, make sure they are installed properly, and keep them in a good condition, you should be consistently hitting the 20% mark.
Still on the fence about a solar panel system? Check out our blog “Do Solar Panels Increase Your Homes Value?” and make the investment for your future today!
Contact us today to discuss your energy wants and needs!