solar panel efficiency

Environmental factors affecting the solar panel efficiency

Solar panel efficiency is actually “the ratio of energy converted to total energy received”. This value, which is usually mentioned as “%”, is used not only in the panel but also in all solar equipment.

Solar panel technology is developing and expanding day by day, however, the efficiency of solar cells is often very low. Most solar cells are less than 20% efficient, meaning they can only convert about 20% of the energy received from sunlight into electricity.

Solar panel efficiency depends on the quality of the materials used in it. No need to say that, solar cells with higher efficiency have a higher price. In addition to the materials used to make the panel, environmental factors also have a significant effect on the efficiency of the solar panel.

In this article, several environmental factors that directly affect the efficiency of solar panels are described and the impact of each is investigated.

1-The effect of sunlight intensity on solar panel efficiency

The flow of electricity produced by the photovoltaic solar panel is highly dependent on the photons received from the sun by the semiconductor material.

Considering that these photons are dependent on the intensity of sunlight, as a result, the energy produced by solar panels increases with the increase of the intensity of sunlight. Of course, this increase in efficiency will continue until the temperature of the surface of the solar panels does not decrease the efficiency of the electricity production of the panels.

solar panel efficiency

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2-The effect of air temperature on solar panel efficiency

Activists in the field of solar energy have used several systems and methods to control the surface temperature of solar panels; to reduce their efficiency as a result of heating due to sunlight.

Among the types of these methods, we can mention natural air flow, forced air flow, water spraying on the surface of solar panels and the new and efficient method of using phase change materials.

Among the above methods, each of which has its own advantages and disadvantages, the last method can be the most suitable option, with a lower initial cost and the need for almost zero maintenance.

Investigating the effect of temperature on solar panel efficiency is defined by a factor called solar panel temperature coefficient. The percentage of the temperature coefficient of a solar panel indicates the amount of change in the production power of the solar panel with an increase or decrease in temperature compared to the standard conditions of 25 degrees Celsius. For example, if the temperature coefficient of a particular solar panel is -0.5%, that means the maximum output power of this panel will decrease by about 0.5% for every 10°C of heating compared to 25°C.

3-The effect of dust on solar panel efficiency

Another environmental factor affecting solar panel efficiency is the quality of their surface, which can be reduced due to the presence of elements such as dust and dirt. By comparing the performance of solar panels in a state free of pollution and in a state where the surface of the panel is covered with dust, the negative effect of the presence of dust on the voltage and current produced by the solar panel is clearly evident.

The presence of dust on the surface of solar panels is discussed with a unit less than 500 micrometers. The effect of dust depends on the density of dust particles and how it is distributed on the panel, which may be partial or uniform.

Each of these factors can reduce the efficiency of solar panels. The characteristics of dust include:

Chemical properties



Dust weight

The environmental conditions of the installation site of solar panels also include factors related to the building and weather conditions of the region, each of which is effective in the effect of dust on the performance of the solar panel. For example, there is a lot of dust in desert areas and it can reduce the electricity production of solar panels by 40%.

The amount of dust settling on the solar panels depends on the placement angle and inclination of the solar panel, the type and material of the surface of these panels, the humidity in the air and also the wind speed of the area.

The effect of humidity on solar panel efficiency


The effect of humidity on the performance of solar panels is in two ways. One is the moisture that forms on the surface of the solar panels and penetrates inside the panel, and the other is the humidity of the air.

The sun’s rays are broken by hitting the particles and vapor droplets in the air, and this causes a decrease in the direct radiation hitting the surface of the solar panels, and as a result, the electricity produced by the panels and the short circuit current decrease significantly.

4-The effect of wind on solar panel efficiency

The effect of wind is defined according to the effects that it can directly and indirectly have on the performance of solar panels. For example, the presence of wind can reduce the surface temperature and thereby increase the solar panel efficiency. On the other hand, the wind blowing in some areas causes dust to spread and settle these materials on the surface of the solar panels, and in this case it reduces the efficiency of the solar panels. As a result, the effect of wind can be considered positive or negative depending on the conditions.

solar panel efficiency

5-The effect of shadow of environmental objects on solar panel efficiency

One of the factors influencing the work of solar panels is shade. The presence of shade on the solar panels can cause the short circuit current to decrease. If the shadow on the surface of the panel is so much that the radiation reaches zero at some point, the shadowed area may be out of the circuit and the output voltage of the solar panel will decrease. Or if the surface is affected by the shadow, the output power of the panel may even be zero.

Sometimes, the presence of only one shadow on a point of the solar panel will actually remove part of the panel voltage and part of the cells from the circuit and reduce the voltage that these cells could produce to zero. Therefore, you should make sure that the solar panels are never placed in an environment that is affected by the shadows of buildings, trees, etc.

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