Solar panel cleaning, set up and proven on your plant

On most utility-scale and C&I plants, the plant’s own crews or its O&M contractor clean the modules. We make that cleaning work: we assess the soiling and the water, prove the method in a pilot, design the method and equipment, train the crews and supply the Chemitek products. Your contractor keeps the contract and the crews, and every service is optional.

As the official Southern African distributor of Chemitek, you can buy just the products from us, with or without our engineers. See the Chemitek range.

Wet cleaning is generally preferred for its cleaning efficiency and lower risk of damage, and dry cleaning is used mostly where water is scarce (Ilse et al. 2019). Dry can be enough for loose dust: see soiling losses in South Africa. The two can be combined. A 115 MWc tracker plant in Chile alternated one wet clean with two dry cleans by tractor brush, four to six times a year (Santiago Solar case). Check the manual first: First Solar allows dry cleaning of its anti-reflective-coated modules only with soft cloths or mops, up to six times a year.

Equipment selection compares the machines in detail, drone cleaning covers hard-to-reach surfaces and low-water cleaning covers water-scarce sites.

Water alone removes loose dust. Bonded soiling needs a product made for it, and a product that leaves a protective layer keeps the glass cleaner between washes.

In a nine-month, peer-reviewed field trial at the Green Energy Park in Morocco, coated systems gained about 3% cumulative energy over a water-cleaned reference (case study). At a utility plant in Honduras cleaned with manual brushes, a string cleaned with Solar Wash Protect produced 1.8% and 2.9% more than two water-only strings over one month (case study). Chemitek reports up to 5% more energy than water-only cleaning, and up to 50% less water. Which product pays on your plant depends on the soiling: Chemitek products explained matches each product to its contaminant.

Water: what the rinse leaves behind

Minerals in the cleaning water deposit on the glass and build up over time (LONGi 2024). Module makers’ hardness, TDS and pH limits differ widely: see cleaning-water testing. Hard-water washing can leave a string worse than before, as the Malaysia case shows. We test the water on site and set the treatment: see hard-water stains.

Keeping it warranty-safe

Module makers set cleaning conditions, and damage from cleaning outside them can void the warranty: Trina’s manual says so in as many words. A letter of conformity covers the product used within the maker’s conditions; the tools and method still have to meet the manual. JA Solar’s 2025 letter for ten Chemitek products, for example, excludes damage caused by cleaning tools. Pressure, brush and temperature limits are in warranty-safe methods. See also cleaning and your module warranty.

How often to clean

LONGi’s manual sets a default of at least one clean every 20–30 days in dry areas and every 40–50 days in rainy ones. The right interval depends on your tariff, soiling rate and what a clean costs, and it changes with the season. The calculator works it out for your plant. See also the cleaning frequency guide and our cleaning strategy service.

On utility-scale and large C&I plants, a free pilot tests the method on your own strings, cleaned beside untouched control strings and read in the same irradiance window.

What it shows depends on what is on the glass. Soiling, the dust, sand and pollen that build up between cleans, is on almost every plant. Solar Wash Protect or Antistatic Solar Armor 2.0 in the normal clean handles it, and usually adds a few percent over water-only cleaning. Contamination, such as cement, limescale, metal oxides or lichen, bonds to the glass and keeps building until it is removed. It needs a removal agent first, then a coating so it doesn’t bond again, and these plants usually gain the most. Published cases show both: