Measured Results: Solar Panels Cleaning Boosts Daily Energy Yield by Nearly 29%
Dust accumulation (soiling) on solar panels is a common but often overlooked issue in photovoltaic power plants. Soiling reduces light transmittance and causes partial shading, directly affecting energy yield.
To evaluate the impact of cleaning, we compared energy yield before and after solar panel cleaning, using on-site photos and operational data from January 6, 2026, at an operating PV plant.
Site Condition (Before Cleaning)
On-site photos clearly show significant soiling on the solar panels, particularly along the lower edges and near the frames, forming continuous dust bands.Such soiling is difficult to wash away naturally and tends to persist on the panel surface over time.
Energy Yield Comparison (Before and After Cleaning)
The comparison was carried out at the same power plant under comparable weather conditions, with all system settings unchanged except for panel cleaning.The daily energy yield comparison is shown below:
| Operating Condition | Daily Energy Yield |
| Not cleaned | 134.86 kWh |
| Cleaned | 173.76 kWh |
Photo date: January 6, 2026
Status: solar panels after cleaning
Daily energy yield improvement:
Ø Absolute increase: 38.90 kWh
Ø Relative increase: approximately 28.8%
These results show that soiling significantly reduced energy yield. Cleaning quickly restored the panels’ energy generation potential.
Why Does Cleaning Lead to Such a Significant Improvement?
Ø Restores Light Transmittance：Dust and contaminants block part of the sunlight. Cleaning allows the panels to receive full sunlight.
Ø Reduces Partial Shading and Current Mismatch：Even sunlight across the panel surface helps the system operate closer to optimal conditions, reducing power losses.
Ø Improves Peak Power Performance：During high sunlight periods, cleaned panels can achieve their rated output.
The results clearly show that solar panel cleaning is not just a routine task, but a key O&M practice that directly affects energy yield.
By implementing systematic and reliable cleaning practices, PV plants can increase generation without adding new capacity, ensuring stable and efficient long-term operation.