How Solar Panel Temperature Coefficient Affect its Efficiency?  

Solar panel temperature coefficient is one of the most important factors affecting your panel’s work. Solar energy is a great alternative to fossil fuels for providing energy independence. However, it has a huge upfront cost. 

Therefore it is imperative to understand how to get the best out of your solar panels. You must be familiar with the temperature coefficient of solar panels before opting for solar energy. 

So, in this article, we will explain everything you need to know about the temperature coefficient of solar panels. 

Understanding The Temperature Coefficient 

Temperature coefficient is a metric that represents the rate at which the efficiency of solar panels decreases when the temperature increases. 

Direct sunlight is required for solar panels to generate electricity when there is too much light and heat it can negatively affect the solar panel’s energy-producing capabilities. 

It is linked with the law of thermodynamics. Heat can limit a panel’s electronic ability, leading to reduced energy production. 

Temperature coefficient reflects this impact of heat on solar panels as a percentage decrease in the output for every 1 degree Celsius rise in temperature from 25 degrees Celsius. 

25 degrees Celsius is a reference point because solar panels are tested for efficiency at this temperature. Every panel has a different coefficient of temperature and it depends on the manufacture of the product. The average range of temperature coefficient for solar panels is between -0.3% °C to -0.5% °C. 

SunPower is one of the oldest solar companies and their panels have a coefficient of -0.37 °C. This means that for every 1°C rise in temperature above 25 degrees, SunPower’s solar panel’s efficiency will decrease by -0.37%.  So if a panel has an efficiency rating of 17% and works at 35 degrees Celsius, its efficiency will decrease to 16.4%. 

This estimation also tells us that a solar panel does not suddenly stop working in high temperatures but endures until it reaches its lowest efficiency as temperature rises. 

As the temperature effect is negatively correlated to the efficiency, it is very rare to get a panel that works fine under hot conditions. So, you might be wondering what is the maximum temperature for a solar panel to work effectively in warm weather. The answer is 95 degrees Fahrenheit. 

The optimal temperature range for normal energy production of solar panels is between 59 degrees to 95 degrees Fahrenheit and anything above or below can compromise the integrity of the panel to a certain extent.

However, modern-day solar panels can go about 185 degrees Fahrenheit. It is a very high temperature but the technology has made its advances. 

Factors that Affect the Solar Panel Temperature Coefficient

Several factors can affect the solar panel temperature coefficient, some of them are listed below. 

The Technology of the Solar Panel 

The first thing that influences the temperature coefficient of a panel is its manufacturing technology. The solar industry has monocrystalline, polycrystalline, and thin-film solar cells, each with a different heat resistance. 

Solar panels with monocrystalline and polycrystalline silicon have high temperature coefficients, which means they will lose more efficiency with a 1 degree rise in temperature. The typical values stand at -0.44% to -0.50%. SunPower simply delivers the best monocrystalline panels with a coefficient of -0.38. 

However, thin-film solar panels are very progressive in terms of endurance against raised temperatures and have low temperature coefficients, closer to -0.2% per degree Celsius. 

Roofing Material

Roof materials also influence how hot solar panels can get. Certain materials absorb more heat than others which tends to push the temperature of the solar panel. Some of the best and most common roofing materials are as below. 

Asphalt Shingles: These are by far the comments roofing material because they are affordable and flexible. But what makes them more compatible is they do not absorb much light, which means they do not generate extra heat for the roof-mounted solar panels. Also, they last for 12 to 30 years so you will not have to change the roof before panels. 

Metal: This type is excellent at reflecting sunlight, especially metal roofs in light color. They have a lifespan of 40 to 75 years and are non-flammable. However, they are a little expensive which makes them a less common choice for those already paying high costs for solar panels. 

Tile Roofing: This material is a great option for hot regions or locations closer to oceans. They last over a century and are less expensive than metal roofs but more expensive than asphalt roofs, however, they can make the installation process complicated. 

Tar and Gravel Roofing: Tar and gravel are also good for solar and are easy to install. Their lifespan is 25 to 30 years. 

What about Wood material? Wood such as synthetic cedar is a good option for a ground-mounted or community solar farm. 

Generally, the roof must have high reflectance so that it remains cool and does not add to the panel temperature. While some materials are cooler than others, a study shows that solar panel keeps the roof shaded from sunlight which is a huge advantage for solar owners in hot climates. 

Location

Your location plays a huge part in not only the efficiency of the panel but also the temperature coefficient. While regions with more sunny days get high energy production it can also affect the coefficient if the temperatures go too high. 

If your region is hot and humid, such as Florida or Texas, you are most likely to deal with high average temperatures daily. This means your roof will have high temperatures most of the time which can affect the panel’s thermodynamics. So if you live in these regions, how can you keep your roof cool?

How to Maximize Your Solar Panel’s Efficiency

As discussed earlier, homeowners in hot climates and high average temperature regions are at risk of losing their solar panel’s efficiency. So here are a few things you must know to cool your solar system. 

Choosing the right roofing material can help, but it’s not the end of the story. Other factors, such as the shading of trees and buildings, the angle, and the direction of your panel. For example, if a roof-mounted system is angled, it will be operating at 30 degrees compared to a roof-mounted flat system working at 35 degrees. 

Similarly, thin-film solar panels have a lower coefficient than mono or polycrystalline. You can consider tha panel’s technology according to the climate of your region. 

Lastly, while the temperature coefficient is an important factor, it’s not the only thing that decides how your panel will work. You can also make better choices at the beginning to avoid efficiency problems. 

Selecting high-quality panels with a low temperature coefficient and improving ventilation, spacing, and shading will help in the long term. 

Comparing the Temperature Coefficient 

Leading solar companies are not working towards making their panels more efficient. Here are some of the best solar panels with reasonable coefficients. 

• Q CELLS -0.42 to -0.37 
• Hyundai -0.45 to -0.41
• LG -0.42 to -0.3
• SunPower -0.38 to -0.29
• Panasonic -0.3 to -0.29

No matter which solar manufacturer you choose to go solar, always do in-depth research and consult with the provider about factors that can influence the efficiency of your solar panel. 

Final Analysis

The solar panel temperature coefficient is indeed an important factor and must be taken into account. However, when we consider long-term production goals and losses that come with a high temperature coefficient, most homeowners might not be significantly affected by it. 

In most of the areas around the U.S., the temperature stays around 25-25 degrees Celsius except in places like Phoenix and Las Vegas where the weather gets extremely hot in summer. Therefore, must discuss these matters with your solar provider before installation. 

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