A photovoltaic system should be cleaned when Contaminants measurably reduce yield.
Typical guidelines:
- Cleaning approximately every 1–2 years
- More common in:
- heavy dust exposure (e.g., industry, agriculture)
- Pollen
- Bird droppings
- Sahara dust events
What's crucial isn't the fixed schedule, but the actual power loss.
How much does soiling affect PV yield?
Contaminants can the PV yield and significantly reduce the economic viability of a plant:
- lower light transmission of the modules
- reduced electricity production
- inefficient plant operation
In practice, Losses in yield ranging from several percent to double-digit figures possible – depending on location and pollution.
Wenn eine PV-Anlage nicht gereinigt wird, kann dies zu einer Verringerung der Stromerzeugung führen. Staub, Schmutz, Vogelkot und andere Ablagerungen auf den Solarmodulen können das Sonnenlicht blockieren und verhindern, dass die Module ihre volle Leistung erbringen. Dies kann zu einer geringeren Effizienz und damit zu einem geringeren Ertrag führen. Darüber hinaus kann eine übermäßige Schmutzansammlung das Material der Module überhitzen, was langfristig zu Schäden führen kann. Auch Korrosion kann begünstigt werden, insbesondere wenn Schmutz Feuchtigkeit speichert. Je nach Standort und Umwelteinflüssen kann die Reinigung alle paar Monate bis hin zu einmal im Jahr oder sogar seltener notwendig sein.
Decreasing efficiency
- less sunlight reaches the solar cells
- lower power production
2. Lower profitability
- lower self-consumption
- longer payback period
3. Possible Damage & Reduced Lifespan
- Persistent soiling can strain modules
- in extreme cases, risk of hotspots or material wear
4. Warranty Risks
- Warranty claims may be limited due to a lack of maintenance.
Don't PV systems clean themselves?
Partly yes – but not entirely.
- Rain removed light dirt
- Inclination angle supports self-cleaning
The problem: Stubborn dirt like:
- Bird droppings
- Dust deposits
- Industrial particles
become not reliably removed.
What cleaning methods are there?
Water-based cleaning (standard)
- low-mineral water
- Possibly special cleaning agents
- gentle and effective
In practice, this is the most common method for commercial installations.
2. Mechanical Cleaning
- Brushes or wipers
- for heavy soiling
Risk: Improper application may damage modules
3. Automated Cleaning
- Cleaning robot (e.g. for Solar parks)
- efficiently with large facilities
What does photovoltaic cleaning cost?
The costs depend heavily on the framework conditions:
- System size
- Accessibility (Flat Roof vs. Pitched Roof)
- Degree of pollution
- Technology used
For large commercial facilities, prices are usually Individual and negotiable.
Is a PV cleaning economically worthwhile?
Yes – if the yield loss due to pollution is higher than the cleaning costs. As a rule of thumb:
- High pollution + large facility = cleaning is usually economical
- Slight pollution = cleaning may not be necessary
Can you clean solar panel systems yourself?
Partially - but with limitations:
Possible with:
- easily accessible flat roofs
- small to medium-sized facilities
- existing security measures
Not recommended for:
- Sloped roofs
- inaccessible facilities
- large commercial systems
Here should Professional service providers be used.
How do you know if cleaning is necessary?
The best foundation is Monitoring:
- Comparison of planned and actual yield
- Sudden performance drops
- visual pollution
Without monitoring, pollution often recognized too late.
Conclusion: Cleaning is not a standard - but an economic decision
Photovoltaic cleaning is not a fixed maintenance cycle, but rather a state-dependent measure. For companies, this means:
- Monitor yield regularly
- Targeted cleaning
- Keep economic efficiency in mind
When used correctly, cleaning provides:
- stable yields
- shorter payback periods
- Long-term asset preservation