A European research team investigated the impact of sand and dust pollution on photovoltaic modules in Oman. They collected 60 samples in different seasons, months and tilt angles.
Scientists from Imperial College London and Karlsruhe Institute of Technology investigated the effects of sand and dust pollution on the glass surfaces of solar modules in Oman. Half of Oman is desert.
They studied the impact of sand and dust pollution on the optical and electrical power performance of photovoltaic panels. Study co-author Christos Markides told reporters: "We have also conducted an economic analysis of dust pollution, but it has not yet been published. The results show that the economic losses are highly dependent on the specific location."
The study was based on 60 samples collected from a sewage treatment station in Muscat, the capital of Oman.
The paper states: “Estimating the power generation of actual photovoltaic installations remains challenging as dust pollution losses may be over/underestimated. Dust pollution losses strongly depend on particle size, shape and associated spectra, which can have a significant impact on the performance of photovoltaic panels. In this paper we present the results of an extensive outdoor experimental testing campaign against sand and dust contamination, applying detailed characterization techniques while taking into account the resulting losses. "
In the paper, "Characterization of glass surface fouling and its impact on optical and solar photovoltaic performance," recently published in the journal Renewable Energy, Markides and colleagues explain that the test samples were produced by Made of iron glass test piece. In the solar industry, these coupons are often used to encapsulate the top layer of photovoltaic modules. They collected glass samples at the end of each month in 2021, distinguishing between rainy season and dry season. During each collection period, the researchers collected four samples at tilt angles of 0, 23, 45 and 90 degrees.
They then sent the samples to London for light transmittance testing. Analysis shows that the relative transmittance of horizontal samples decreases by 65% in the rainy season, 68% in the dry season and 64% year-round.
The research team added: "In comparison, the relative transmittance of the vertical test piece decreased by 34%, 19% and 31% respectively. The average of the wet test piece, dry test piece and one-year test piece at three different tilt angles The relative transmittance is reduced by 44%, 49% and 42% respectively."
Based on these results, the researchers calculated the expected power losses of monocrystalline PV modules under standard test conditions, namely a radiation intensity of 1000 W/m2 and a temperature of 25 degrees Celsius.
They added: "The relative transmittance decreases measured using wet season, dry season and year-round horizontal samples correspond to 67%, 70% and 66% of the predicted relative decreases in power generation, respectively. Estimated at a local tilt angle of 23 degrees, monthly The relative transmittance loss is approximately 30%, resulting in an approximately 30% decrease in equivalent relative photovoltaic power at the study site each month."
The scientists then used X-ray and electron microscopy to analyze the characteristics of the soil particles. Since all the glass samples were taken from the same place, the scientists assumed their dirt had exactly the same material characteristics. Therefore, they only analyzed horizontal glass specimens during the wet and dry seasons and year-round.
They emphasized: "X-ray diffraction (XRD) results show that the year-round sand and dust pollution test pieces contain a variety of minerals, such as silica, calcium carbonate, calcium magnesium carbonate, titanium dioxide, iron carbide and aluminum silicate. Element distribution Figure highlights the compounds reported by XRD analysis. The most dominant element is silicon (Si), the remaining elements include carbon (C), oxygen (O), sodium (Na), magnesium (Mg), aluminum (Al), calcium (Ca) and iron (Fe).”
The researchers also found that dry season samples had more PM10 particles than rainy season samples. PM10 are inhalable particulate matter less than 10 microns in diameter. "The study also demonstrates that periodic rainfall can naturally wash away accumulated large particles, but not small particles," they explain in the paper.