Large solar power plants are usually built in deserts, where there is plenty of space to install thousands of panels to generate energy. In addition, there are rarely cloudy days there, so the sun is almost always shining. But there is one big problem: every day, a large amount of sand and dirt settles on the surface of solar panels, due to which less electricity is generated. Home solar panels can simply be hosed down or brushed off. But what if there are thousands or even millions of panels? Are there really teams of workers who walk every day under the scorching sun and wash it all by hand?
It is impossible to manually clean millions of solar panels, so what solution have engineers found? Source: philergy.com
Cleaning solar panels with water
It goes without saying that large solar power plants don't have thousands of workers cleaning them by hand. This is simply impossible, because solar panels are installed on lands with an area of tens or even hundreds of square kilometers. For example, the world's largest solar power plant, Midong, stretches over 133.5 square kilometers and consists of more than 5 million solar panels.
At small stations, you can pour the panels manually. Source: eenergy.media
Most often, solar panels are doused with water using heavy equipment or aircraft. Water quickly washes away all the dirt, but in the desert it has to be delivered by truck, which is very expensive. In addition, it must be clean so as not to leave deposits on the surface of the panels, which in themselves are dirt.
Cleaning solar panels using a drone. Source: sciencetoday.ru
According to MIT Technology Review, washing solar panels uses 10 billion gallons of water each year. That's enough water to provide drinking water for about 2 million people. So washing solar panels with water is considered an effective, but very expensive method.
Read also: Thailand opens largest floating solar power plant
Robots for washing solar panels
Another effective, but less expensive way to clean dust from solar panels is to use special equipment. At the Shams 1 power plant near Abu Dhabi, United Arab Emirates, panels are cleaned using huge brushes on the machine's robotic arms, according to IEEE Spectrum magazine. Using this tool, 258,048 mirrors are cleaned, which cover an area of 2.5 square kilometers. The station management believes that it is not necessary to clean the panels perfectly – the main thing is that their reflectivity does not fall below 85%.
Machine with brushes for cleaning solar panels. Source: spectrum.ieee.org
Solar power plants also use robotic vacuum cleaners. In 2023, Reiwa Engine and Enel Green Power developed the Sandstorm robot for dry panel cleaning. He uses brushes to get rid of dust, and wheels with good grip to drive. The device is able to move across the panels, even if they are not installed level. He can also step from one panel to another, even if there is a gap of up to 50 centimeters between them.
SandStorm robot for cleaning solar panels from dust. Source: newatlas.com
One of the largest solar power plants, Noor Abu Dhabi, which is located in the desert in the northeast of the emirate of Abu Dhabi in the UAE, also employs robots. Their number exceeds 1,400 pieces – this is enough to clean 3.3 million panels per day twice a day.
An interesting question:Can a solar power plant generate electricity using at night?
Coating from dust and moisture
Cleaning with water and brushes is, of course, good. But water is too expensive a resource, and brushes scratch the surfaces of the panels, reducing their efficiency. It would be much better if dust simply did not settle on the surface of the panels. Scientists have developed such a technology.
In 2022, a group of engineers from the Massachusetts Institute of Technology developed a technology for cleaning solar panels using electricity.
Perhaps in the future, solar panels will not get dirty at all. Source: inbusiness.kz
The idea turned out to be simple. Scientists proposed to stretch electrical conductors under the panels, which create an electric field above them. It transfers a charge to dust particles, and the opposite charge of the battery itself repels them. Laboratory tests showed that the system works, and is capable of cleaning even at air humidity of up to 95%.
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In addition, over the years, solar panels have been covered with hydrophobic solutions and antistatic agents. The former repel raindrops and other liquids, and the latter eliminate static charge so that dust is not attracted to the panels. This is a good way to increase the life of solar panels, but you can't do without cleaning them using one of the above methods.