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Cleaning Solar Panels – 5 Practical Tips

What You Should Consider When Cleaning Large-Scale PV Systems

  • Expert Knowledge

Clean solar panels for maximum yields – the key questions about cleaning

Photovoltaics continue to be in strong demand in Germany—especially in industry. With a 23.2% share of electricity generation from renewable energy sources, solar energy, alongside wind power, is one of the most important pillars of the energy transition. However, as the technology grows, practical questions arise: How can solar panels on large rooftop systems be cleaned efficiently and safely? What cleaning equipment is available? We show the dos and don’ts of machine-based solar cleaning with robots.

How Often and With What Should You Clean a Solar Installation?

For optimal performance, operators should clean their PV modules regularly. Contamination such as bird droppings, grease, or rust dust significantly reduces efficiency and can noticeably lower maximum output—with direct effects on self-consumption, grid feed-in, and remuneration. How often cleaning is required depends primarily on location and rainfall. In agricultural regions, professional solar cleaning is recommended at least once a year.

Which Cleaning Methods Are Suitable for Industrial Solar Cleaning?

Cleaning robots are indispensable in modern facility cleaning operations. The same applies to the cleaning of large PV systems. Here, solar cleaning robots particularly excel due to their high efficiency and environmental compatibility – because the high rotation of the brushes ensures an optimal cleaning effect without health-hazardous and environmentally harmful chemicals. Furthermore, if you clean with osmosis water instead of conventional water, the positive effect is maximized.


For the regular cleaning of the solar installation with the PV cleaning robot to be efficient and safe, several important points must be observed:

5 Tips – Cleaning Large Solar Installations: How to Do It Correctly

Solar cleaning robots significantly increase safety because people no longer need to step onto the roof. Instead of manual cleaning at height, the robot does the work while specialists control and monitor it from the ground. Additional sensors (e.g., edge detection) minimize the risk of falls or misdriving.
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The cleaning behavior of solar robots can be specifically adjusted depending on the level of soiling and the roof pitch. By using a safety rope and suitable track belts—such as rubber for ammonia-containing residues—optimal traction and effective cleaning are ensured. Replaceable materials such as leather, rubber, or neoprene allow flexible adaptation to different surfaces.
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Solar cleaning robots achieve traction via chain-driven running gear, whose track belts can be changed flexibly depending on the degree of soiling. Different variants enable safe use from dry cleaning through to heavily soiled surfaces. For optimal grip, a brief pre-cleaning of individual modules and correct hose routing are crucial. In addition, the roof pitch should be measured in advance, as the devices—depending on the model—are designed for inclines of up to 25°.
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For optimal cleaning results, pre-cleaning and main cleaning with water are recommended, ideally with demineralized (osmosis) water, which is gentle yet effective. A sufficient amount of water is crucial, as too little water creates friction and reduces the rinsing effect. Solar robots operate in the low-pressure range—two to four bar is usually sufficient—although differences in height and hose length reduce the pressure. An adequately large hose diameter is also important to supply enough water. High-pressure cleaners should be avoided, as they can damage the module surface.
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To ensure the service life of the solar cleaning robot, the battery should be recharged regularly, especially during the winter months. Similar to e-bikes, so-called “battery jogging” is important to maintain capacity and performance. This includes operating the robot occasionally outside the main season instead of leaving the battery unused for long periods. This ensures long-term readiness for use.

Robots Revolutionize Professional Solar Panel Cleaning

The use of solar panels is growing far beyond agriculture. To ensure systems deliver consistently high yields, regular cleaning is essential—an attractive opportunity for both operators and cleaning service providers. Solar cleaning robots have proven to be a safe and efficient solution. Those who consider safety aspects, water pressure and volume, machine maintenance, roof conditions, and battery checks are optimally prepared for a successful solar season.

Would you like to learn more about the possibilities of a cleaning robot or our cleaning systems? Then please contact us; we would be happy to advise you!

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FAQ

General

Contamination such as dust, pollen, bird droppings, or industrial deposits reduces the amount of light reaching the panels and therefore the electricity yield.

Even light soiling can cause a 5–20% drop in performance—on large systems, that can quickly amount to several thousand euros per year.
Calculate your loss here.

As soon as there is a measurable loss of yield or visible soiling. For commercial systems, cleaning often pays off after just one season.

Cleaning intervals

Generally every 12–24 months. In dust-intensive regions or in agriculture/industry, often more frequently.

Typical signs are declining yields, visible dirt, staining, or uneven module surfaces.

Methods & technology

Manual cleaning, automated robot cleaning, and osmosis processes—depending on system size and accessibility.
For large areas, robots are more efficient, safer, and more consistent. Manual methods are better suited to small systems.
High pressure can cause microcracks, damage seals, and jeopardize the module warranty.
It prevents limescale and streaking and ensures residue-free cleaning.

Safety & responsibility

Yes—especially for rooftop systems. Fall risk, module breakage, and liability issues make professional methods advisable.

In principle, this is possible, but for commercial and large-scale systems it is not recommended for safety and liability reasons—unless you invest in appropriate safety training. In many cases, a rental service with trained personnel is a good option. This ensures the cleaning is carried out professionally, all safety requirements are met, and potential damage to the system or roof is avoided. At the same time, operators benefit from professional technology and experience without having to train their own staff or keep specialized equipment on hand.

Cost-effectiveness

Depending on size and soiling, usually between €2–€6 per square meter

In many cases, yes—the additional electricity yield often clearly exceeds the cleaning costs.

Automation

Robots move autonomously over the modules, brush the surface, and use water or dry methods—consistently and gently on materials.

For industrial halls, solar parks, and large roof areas with several hundred square meters of module surface.

Decision questions

For large systems, hard-to-access roofs, or when consistent cleaning quality is required.
Maintenance checks the technology—cleaning relates exclusively to the module surface and yield.
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