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The Science Behind Solar Panel Soiling Loss: Understanding the Mechanisms

Solar panels have become a popular source of renewable energy in recent years, offering many benefits such as lower energy costs, reduced carbon emissions, and increased energy independence. However, one of the most significant challenges facing solar panels is soiling loss, which can reduce their energy output by up to 30%. In this blog post, we will explore the science behind solar panel soiling loss and the mechanisms that cause it.



Soiling loss is the reduction in power output due to the accumulation of dirt, dust, and other debris on the surface of solar panels. The accumulation of debris can be caused by a variety of factors, including natural weather conditions, such as wind, rain, snow, and humidity, as well as human-made factors, such as air pollution and industrial activity.


The primary mechanism that causes soiling loss is the absorption and scattering of sunlight by the accumulated debris on the surface of the solar panel. Sunlight is absorbed by the debris, reducing the amount of light that reaches the solar cells, which reduces the energy output of the solar panel. Additionally, the scattered light can also be reflected away from the solar panel, reducing the amount of energy that the panel can generate.


The impact of soiling loss can vary depending on the type of debris that accumulates on the surface of the solar panel. For example, in areas with high levels of air pollution, the accumulation of particulate matter, such as smoke and smog, can be a significant cause of soiling loss. These particulates can absorb and scatter sunlight, reducing the energy output of the solar panel.

In arid regions, dust and sand accumulation can be major causes of soiling loss. The accumulation of dust and sand can be especially problematic in areas with high wind speeds, where the debris can be blown onto the surface of the solar panel. In humid regions with more frequent rain, organic matter such as pollen, leaves, and bird droppings can also cause soiling loss. All of these different soiling types will result in different absorption and scattering patterns. Therefore, it's important that any soiling monitoring device is capable of handling many different scenarios.


The impact of weather on soiling loss can also depend on the angle of the solar panel. Panels installed at an angle that prevents effective self-cleaning can become coated with a layer of dust or dirt that reduces their energy output.


Regular cleaning can help to remove the accumulated debris on the surface of the solar panel, which can improve their energy output. In addition, proper installation of the panels can also help to minimize the impact of soiling loss. Panels installed at an angle that allows for effective self-cleaning, or that are protected from wind and snow, can help to minimize the impact of soiling loss.


At an industrial level, more sophisticated mechanisms are available to determine and predict soiling loss and solar panel output such as soiling loss monitors and predictive software that calculates optimum washing cycles. This is where the ARES soiling monitoring device comes into play. Using large area reference cells along with sophisticated software, we are able to project wash schedules along with the economic benefits of following different wash scenarios.

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