Granular dust soiling happens when dust settles on the module glass. The dust lowers how much light the glass lets through, which reduces array current and energy output. It shows as a slow drop in irradiance-normalized production during dry spells. Output often recovers partly or fully after real rain or a wash, and the plant stays online throughout. The loss is usually spread across a whole zone. Roads, bare soil, farming, construction, prevailing wind and row edges can make it uneven, and uneven dust can also cause mismatch between strings or substrings. To confirm it, find dry periods where output falls even though availability, clipping, curtailment and sensors are all fine. Then compare those periods with soiling station data, rainfall, cleaning logs and nearby reference blocks. Do not judge soiling from one dirty irradiance sensor alone, because sensor drift, poor cleaning or a local obstruction can look like soiling. Check that the soiling model matches the recovery you actually see after rain or cleaning. If it does not, update its accumulation and wash-off assumptions, then set cleaning triggers by the value of the lost energy.
caused_byc1 drafted · lead Surface soiling
Granular dust settles on the module glass and builds up between rain or cleaning events.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h5 h=43575746a7d7c2 drafted · lead Extended dry periods
Losses build up during dry spells when there is no rain to wash the dust off.
sec=h4 h=dea316ba61e1sec=h6 h=d8fc1b85b960c3 drafted · lead Nearby agricultural activity
Can make dust loss spatially uneven across the plant.
sec=h4 h=dea316ba61e1c4 verified · fact Nearby construction activity
Can make dust loss spatially uneven across the plant.
sec=h4 h=dea316ba61e1verified by: joshuahamsaverified on: 2026-10-16
c5 verified · fact Unpaved roads and exposed soil
Roads and bare soil nearby can raise local dust deposition.
sec=h4 h=dea316ba61e1verified by: joshuahamsaverified on: 2026-10-16review note: support check: partial - Roads and exposed soil are named as causing spatial unevenness, but the passages don't state they raise local deposition.
affectsc6 verified · fact Module front glass
Dust deposited on the glass lowers its transmittance.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37verified by: joshuahamsaverified on: 2026-10-16
c7 verified · fact Solar cell
Particles scatter and absorb light, so less light reaches the cells.
sec=h4 h=dea316ba61e1sec=h5 h=43575746a7d7verified by: joshuahamsaverified on: 2026-10-16
presents_asc8 verified · fact Gradual performance decline
Irradiance-normalized production declines gradually through dry periods while the plant stays online.
sec=h4 h=dea316ba61e1verified by: joshuahamsaverified on: 2026-10-16
c9 drafted · lead Recovery after rainfall
Output recovers partly or fully after meaningful rain.
sec=h4 h=dea316ba61e1c10 verified · fact Production step after cleaning
Output recovers after washing.
sec=h4 h=dea316ba61e1verified by: joshuahamsaverified on: 2026-10-16review note: support check: partial - Recovery after washing is stated, but a 'step change' in production is not explicitly described.
c11 drafted · lead Reduced string current
Dust lowers module and array current.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h5 h=43575746a7d7c12 verified · fact Spatially uneven loss
The loss is usually broad across a zone, but local dust sources, prevailing wind and row edges can make it uneven. Uneven deposition can also cause mismatch between strings or substrings.
sec=h4 h=dea316ba61e1sec=h5 h=43575746a7d7verified by: joshuahamsaverified on: 2026-10-16
detected_byc13 drafted · lead Performance ratio trend analysis
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960c14 verified · fact Soiling station
Do not rely on a single dirty irradiance sensor. Drift, poor cleaning practice or a local obstruction can mimic soiling.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h7 h=445831ccd5f3sec=h6 h=d8fc1b85b960verified by: joshuahamsaverified on: 2026-10-16
c15 verified · fact Rainfall response review
Check whether output recovers after rain as the soiling model predicts.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960verified by: joshuahamsaverified on: 2026-10-16
c16 verified · fact Cleaning log review
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960verified by: joshuahamsaverified on: 2026-10-16
c17 verified · fact Weather-normalized production comparison
Uses irradiance-normalized output during dry accumulation periods.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960verified by: joshuahamsaverified on: 2026-10-16
c18 drafted · lead Soiling model residual analysis
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960c19 verified · fact Reference block comparison
Compare with nearby reference blocks when they are available.
sec=h6 h=d8fc1b85b960verified by: joshuahamsaverified on: 2026-10-16
mitigated_byc20 drafted · lead Cleaning schedule optimization
Set cleaning triggers by the value of the lost energy.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37c21 drafted · lead Soiling model calibration
Calibrate local accumulation and wash-off assumptions against operational data before using the model for cleaning economics.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h5 h=43575746a7d7sec=h6 h=d8fc1b85b960distinguished_fromc22 drafted · lead Grid Curtailment Yield Losses — told apart by Performance monitoring
Dust loss shows as declining normalized output in dry periods with no matching availability, clipping or curtailment events, and it recovers after rain or cleaning.
sec=front h=931a735f2be9sec=h2 h=5d4993c87d37sec=h6 h=d8fc1b85b960review note: support check: partial - Passages say dust decline occurs without curtailment/clipping events and recovers after rain, and say to separate from curtailment, but don't explicitly state a comparison with grid curtailment losses via performance monitoring.
distinguished_from c19