Research vs. dirty photovoltaic panels
The impact of dirt on the performance of photovoltaic panels and the importance of regular cleaning: A review of European studies
The performance of photovoltaic panels depends on many factors, such as insolation, temperature, angle of inclination and condition. One often overlooked but extremely important aspect is the impact of dirt on the surface of photovoltaic modules. Dust, dust, leaves, bird droppings and other contaminants can drastically reduce the efficiency of the installation. This consequently leads to a decrease in energy production. Regular cleaning of photovoltaic panels becomes crucial to maintain their optimal performance.
Research vs. dirty photovoltaic panels. What dirt affects the performance of photovoltaic panels?
Fouling of photovoltaic panels can be divided into several main categories:
- Dust particles: In regions with high levels of air pollution, dust settles on the panels, reducing the access of sunlight to the modules.
- Bird droppings: Local light blockages are often created by bird droppings, leading to a hot-spot effect that can damage modules.
- Leaves and organic debris: They can block part of the panels, causing inhomogeneity in the lighting of the modules.
- Precipitation: although rain can partially wash away dirt, it is not always sufficient, especially in regions with low rainfall.
The importance of regular cleaning
Cleaning photovoltaic panels has become an integral part of maintaining their performance. Neglecting this aspect leads to:
- Decrease in energy production, depending on the intensity of soiling by up to 15-30%.
- Increase the risk of failures related to local overheating of modules (hot-spot effect).
- Increase in operating expenses due to loss of potential revenue from energy production.
Research vs. dirty PV panels. A review of European research on the effects of dirt on PV.
Numerous studies have been conducted in Europe to assess the impact of soiling on the performance of PV panels and the effectiveness of various cleaning methods. Below are four major European studies in this area:
Study of photovoltaics under industrial conditions in Spain
One study conducted in Spain analyzed the impact of soiling on large PV farms in the southern regions of the country. The results indicated that the average efficiency loss associated with soiling was about 8-10% per year. However, in regions with high levels of dust in the air (e.g., near factories), these losses could be as high as 20%.
German study: effect of dust and precipitation on panel performance
A study was conducted in Germany on the effect of dust on the performance of panels in different weather conditions. It was found that dirt had a particularly high impact during dry periods, where natural precipitation did not occur for long periods of time. The study suggested that regular cleaning every 3-6 months could reduce performance losses by up to 12%.
Research vs. dirty photovoltaic panels. UK urban survey
In the UK, studies have been conducted in urban areas. There, pollution is particularly high due to vehicle and industrial emissions. The results showed that in densely populated urban areas, the efficiency of the panels dropped by about 15% per year. However, regular cleaning at least twice a year kept the modules fully operational.
Italian study on impact of bird droppings
An Italian study analyzed the specific problem of bird droppings on photovoltaic farms located near agricultural and forest areas. Bird droppings were found to be one of the main factors responsible for local overheating of the modules, resulting in permanent damage. Regular inspection and removal of this debris could reduce the risk of failure by 20%.
PVPS Task 13 study – International Energy Agency (IEA).
As part of the IEA’s international PVPS Task 13 project, extensive research has been carried out on the long-term performance and reliability of PV systems under different geographic conditions. During this research, particular attention was paid to the impact of fouling on system performance in various European countries, including France, Germany and Italy. It was shown that fouling can cause a loss of performance ranging from 5% to 20%, depending on the region and the intensity of the fouling. High dust concentrations and longer periods without rain in Southern Europe (Spain, Italy) led to the greatest losses. The study recommended regular cleaning of panels, especially on industrial farms, to maintain stable levels of energy production.
Research vs. dirty photovoltaic panels. Fraunhofer Institute Study (Fraunhofer ISE) – Germany
The Fraunhofer Institute, one of Europe’s most prestigious solar research institutes, has conducted research on the degradation of PV panel performance due to dirt. One project analyzed the performance of PV systems under various climatic conditions across Germany, particularly in industrial and agricultural areas. It showed that regular soiling, including dust and pollen, can reduce energy production by up to 7% per year. In rural areas, where pollen and agricultural dust predominate, productivity losses can be even higher, especially during summer periods. Fraunhofer ISE has recommended regular monitoring and cleaning of installations in these regions.
Study of the Polytechnic University of Milan (Politecnico di Milano) – Italy
The Polytechnic University of Milan has conducted a study on the impact of pollution on the long-term performance of photovoltaic systems in urban and industrial regions in northern Italy. The results of the study showed that pollution from traffic, industry and atmospheric pollutants can cause an average annual drop in performance of 6-12%. It also showed that this effect can be even greater during dry periods, when the lack of rainfall does not naturally wash away dirt. The study emphasized that regular cleaning of photovoltaic panels in urban areas can contribute to a significant increase in energy production.
Research vs. dirty photovoltaic panels. University of Lisbon (Universidade de Lisboa) study – Portugal
In Portugal, where solar insolation is very high, a study by the University of Lisbon focused on assessing the impact of dirt in regions with Mediterranean climates. Photovoltaic systems were analyzed in various locations, including the coast and inland. The results showed that fouling from sea salt in coastal regions and dust from the Sahara in more inland regions can cause performance drops of 10-15%. The study found that regular cleaning of the panels, especially during the summer season, can prevent significant energy losses.
University of Patras study – Greece
In Greece, due to the hot and dry climate, dirt on photovoltaic panels has a significant impact on their performance. A study conducted by the University of Patras focused on analyzing the impact of dust and bird droppings on photovoltaic installations in rural regions. The results of the study indicated that dirt, especially during the summer, can reduce energy production by 10-25%. They recommended more frequent cleaning there, especially for large agricultural installations.
Research vs. dirty photovoltaic panels. Based on the research, a clear conclusion can be drawn.Regular cleaning and washing of photovoltaic panels is crucial to maintain their full performance.
In regions with high levels of pollution, cleaning is recommended at least twice a year. While in areas with less pollution – every 6-12 months. It is also worth investing in automatic cleaning systems or the services of specialized companies. They are able to adapt the cleaning method to the specific conditions in which the plant operates.
Taking care of the cleanliness of the panels not only maintains the high efficiency of the systems, but also extends their life. This, in turn, translates into a better return on investment in solar energy in the long term.
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