The Economics of PV Soiling and Solar Panel Cleaning

The Economics of PV Soiling and Solar Panel Cleaning

Case Study

*PPA value: $28/MWh (CAISO), Site Size:100 MW

Reduced Asset Life due to PV Soiling

Solar panels are sold with an expected lifespan of 25 years usually. However, they accomplish this lifespan if they are maintained well. If they are not cleaned, they will not make it to 25 years. The estimated lifespan of a solar panel is based on the maintenance guidelines of each manufacturer and every manufacturer recommends regular cleaning. However that said, manufacturers keep cleaning guidelines vague and mention that cleaning is site-specific. 

If you do not clean regularly, it is unlikely that your solar panels will make it to that 25-year mark. 

3 main drivers for solar panel hotspot development include. 
  • Soiling/Shading
  • Mechanical damage
  • Internal module failures

Hot spots cause the heating of adjacent cells and cause a significant decrease in output power.

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Source: https://pv-magazine-usa.com/2016/09/06/melting-backsheets-broken-cells-and-hotspots/

Here is an example of what happens when your installation does not have a microinverter and it does have soiling issues. 

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Source: https://www.solarreviews.com/blog/pros-and-cons-of-string-inverter-vs-microinverter

Less predictability and reliability

The income generated by selling clean energy to the grid is more valuable if it is reliable and predictable. Constant revenue streams are often valued by pension funds and other financial entities and asset owners that excel at O&M often win this group’s interest. 

A high-quality solar panel cleaning strategy is part of any preventative maintenance or condition-based maintenance program. 

According to NREL

“Preventive maintenance: Scheduling and frequency of preventive maintenance is set by the operations function and is influenced by a number of factors, such as equipment type, environmental conditions at the site (e.g., marine, snow, pollen, humidity, dust, wildlife), and warranty terms. Scheduled maintenance is often carried out at intervals to conform to the manufacturer’s recommendations, as required by the equipment warranties”

“Condition-based maintenance: Condition-based maintenance is the practice of using real-time information from data loggers to schedule preventive measures such as cleaning or to head off corrective maintenance problems by anticipating failures or catching them early. Because the measures triggered by condition are the same as preventive and corrective measures, they are not listed separately. Rather, condition-based maintenance affects when these measures occur, with the promise of lowering the frequency of preventive measures and reducing the impacts and costs of corrective measures.”