Effect of Temperature on Solar Panels

Aug 26, 2019 | Going Solar, Solar Panels

Our intuition is solar panels perform better at high temperatures.  That is not true!

When solar radiation is high, generally ambient temperatures tend to increase. But, the output of solar panels decreases with increase in temperature. Although high temperature does not affect the amount of radiation/energy received by the solar panels, it decreases the amount of energy converted (voltage generated) by the solar panels.

Effect of Temperature on Solar Panel Output

Power-Temperature Coefficient for Solar Panels

Now that we understood that high temperatures decreases efficiency of a solar panel, then next question is how much it decreases?

Solar panel manufacturers use temperature coefficient as a parameter to quantify this decrease in power. Ratings of solar PV panels are mentioned at temperature of 25°C.  Temperature coefficient signifies a change in solar panel efficiency with a 1°C change in temperature from 25°C.

A typical solar panel operates anywhere between the ambient temperature and might reach as high as 70°C in summer in India.  So, let us assume that on a particular hot day, solar panel temperature has reached 50°C. Therefore, a solar panel with a temperature coefficient of -0.4% would result in the reduction of maximum power by 10%. When it is sunny on a cold winter day, the solar panels would actually be more efficient.

Silicon-based monocrystalline and polycrystalline solar panels usually have a temperature coefficient between -0.29% to -0.45%. Choosing the right panel that has suitable efficiency for your needs goes a long way in improving your financials.

Panel Type

Temperature Coefficient of Power

Poly Crystalline 72 Cell

-0.38 to -0.40% /°C

Poly Crystalline 144 Half Cell

-0.37 to -0.39% /°C

Mono Crystalline PERC 72 Cell

-0.37 to -0.39% /°C

Mono Crystalline PERC 144 Cell

-0.36 to -0.38% /°C

Mono Crystalline HJT

-0.29% /°C

Check out more about – Type of solar panels in India.

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How to Reduce the Effect of Temperature on Your Panels?

During Manufacturing– the best solar panel manufacturing companies use thermally conductive substances while making the panels to help release excess heat through the glass layer. However, this alone is not sufficient.

During Installation– while mounting the panels, either on the ground or on rooftops, it is advised to leave enough space to allow free flow of air above and below the solar panels to reduce the temperature. 

For ground-mounted solar PV panel installation, the solar installer will design the plant by elevating the panels a few inches above the ground. Also, a layer of grass can be placed under the panels to ensure relatively lower temperatures than bare soil beneath the panels.

For roof-mounted solar system installation, ventilation systems or fans can be added to the solar PV system to help in the movement of air near the panels.

During maintenance– It is advisable to gush water on the panels to maintain power efficiency. However, the availability and sometimes, the cost must be considered before opting for this option.

In addition to these, having a light-coloured roof might reduce the temperature around the panels compared with a dark-coloured roof.

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