Atonometrics was founded in Austin, Texas, in 2007, with the mission to provide high-quality test and measurement equipment to the small but growing photovoltaics industry. The company founders came from a long background in test and measurement equipment for the semiconductor industry. The experience of the management team included over 30 years of R&D, product development, sales, marketing, and manufacturing.
The company’s first products included light soaking systems and IV measurement systems for PV module manufacturers and test labs. These products have been installed in factories and labs worldwide.
This experience in the PV industry led the company to develop products for operational PV plants. The company’s first soiling measurement system was introduced in 2010 and that product was followed by calibrated reference cells for cost-effective irradiance measurements.
Soiling: the accumulation of dust and other contaminants is a significant concern for photovoltaic (PV) solar power plants. Soiling affects solar power generation by blocking sunlight from getting to the solar panels. It causes worldwide solar industry power losses of 4 to 7%, with corresponding revenue loss in the multibillion-dollar range. And some locations, such as the Middle East, can experience soiling losses of 50% or more during dust storms.
Soiling occurs primarily because airborne particulate matter settles onto the surfaces of solar panels and sticks to them. The rate of soiling accumulation, usually discussed in terms of the daily increase in power loss in between cleanings, varies between 0.1 to 1.0 percent per day, depending on the amount and type of dust in the air, wind speeds, humidity, and other conditions. The total soiling loss continues to grow until a cleaning or rainfall event occurs.
Soiling is a location-specific phenomenon. Not only are there are clear differences in soiling rates between geographic regions, but even on the local scale there can be significant differences in soiling rates depending on local surroundings. Soiling rates can even vary significantly across a single PV power plant, perhaps due to a road, farm, or factory on one side of the plant or due to prevailing winds. Studies have reported up to 3% performance variations across a single plant due to location-specific soiling rates.
For PV power plant sites without regular rain, cleaning strategies need to be developed, keeping in mind the costs of cleaning which vary significantly by cleaning method and plant location. The decision of how often and when to clean is an economic one, increases in revenue due to cleaner solar panels should exceed losses due to soiling.