Solar Panel Cleaning Standard Operating Procedure (SOP)-Engineers Guide

Cleaning of Solar PV Modules are the most important O&M practice to keep the module efficiency up and ensure high output from the plant. Here is the Solar Panel Cleaning Standard Operating Procedure (SOP) which will help in effective PV module cleaning process.

Why periodic solar panel cleaning is necessary?

Solar panels work by converting sun-light (Photon Energy) that falls onto solar panels which covert into electricity. Solar Panel will generate more power when more Radiation hit on Solar plate. If the panel is dusty or some material, particles fallen on it, then it will not capture more sunlight or Radiation. A dirty solar panel decreases the efficiency of a solar system. Below are some reasons why it is necessary to clean solar panels. Have a look!

Regular cleaning ensures that your solar panels are in perfect working condition. It reduces the cost of changing the panels often.

Periodic cleaning will improve module efficiency which will provide maximum output.

PV Module starts degrading faster due to deposition of Dust layer, which creates Hot Spot in Cell.
Many solar manufacturers have made frequent cleaning a warranty requirement. Due to routine cleaning many PV module fault can be eliminated. As a result, it is advisable to regularly clean solar cells to be on the safe side.
If you live where it rains regularly, you might think it is unnecessary to clean the panels, but rainwater might have dust in it. This can create scaling on PV module. So, it is advisable to check whether your plate is properly cleaned or not.

Before Cleaning
After Cleaning

According to an estimate, regular cleaning of solar panels has potential to increase power output by as much as 30%.

Solar Panel Cleaning Standard Operating Procedure (SOP)

Safety considerations to follow for cleaning solar panels.

Before starting any cleaning activity, ensure to take necessary safety precautions to avoid any hazards. Wear protective equipment, such as gloves and safety glasses. Identify what Risk associated with the work.

Do not clean solar panels when the weather is terrible.

Module Cleaning work should be performed during non-peak hours as per OEM Guidelines.

Ensure proper lighting during work.

Ensure proper cleaning tools to be used.

Make sure the roof has a strong build that can hold your weight.

Cracks in modules or damaged cable or joints in a string are extremely dangerous for cleaning person particularly when the modules are wet. Wear proper safety PPE’s.

It is most important to wear safety equipment before cleaning the panels.

Procedure to Follow for Module Cleaning

  1. Permit to work to be obtained before starting work.
  2. Check and ensure the competency of the person who will perform the task.
  3. Ensure that all recommended PPE are available with working team and they know how to wear the same to ensure they are wearing correctly while working.
  4. The workers will be communicated about the hazards, associated risks and Isolation Procedure through Toolbox talk to avoid the ignorance/Unacceptable risk through Water cleaning (Water fed type or simple wiper type) or Robot Cleaning.
  5. The walkways/vehicle movement pathway in between the row, must be cleared from any obstructions as sand dunes, rat holes etc. to avoid the trip, slip, and water tanker fall hazards.
  6. Drive of vehicle on good way, conditioned road and avoid driving so close near solar panels to avoid the hitting against the structures by vehicle.
  7. Use seat belt and Safety Helmet who are moving through water tanker vehicle/Tractor.
  8. Drinking water should carry to work area to avoid dehydration in Day time in summer season.
  9. Look around for road condition and open underground cable if any to avoid physical injuries.
  10. Use Gumboot, Helmet with mining lamps wherever physical hazards existing in work area.
  11. If the task is being performed during night, ensure adequate illumination, and obtain the night work permit.
  12. Water tanker with Engine of vehicle should park with wheel blocker/Chocker to avoid unwanted vehicle movement.
  13. Hose pipe pressure should not cross 6 bar/ The pressure should not damage modules. Do not use any high-pressure water because this might damage the panels.
  14. Don’t clean the module having broken glass or exposed wiring. This can cause a electrical failure of the module or electrical shock Hazards.

Also Read: Basic Solar Energy Engineer Interview Questions and Answers (Q&A)

Tips for Solar Panel Wet Cleaning

  1. During Wet cleaning, quality of water is crucial when cleaning solar modules. Hard water may cause defects on module as in long time frame you will observe water scaling due to deposition of high mineral content on glass surface. It will decrease module efficiency. So, it required to test your water frequently from Trusted LAB. If Hardness found more, then you can opt for RO system for Module washing. High mineral content water is not recommendable.
  2. For Good Wet cleaning, you need to have good quality wiper or brush. Always use water & Sponge cloth for Cleaning. A mild, non-abrasive cleaning agent can be used to remove stubborn dirt. Do not use abrasive sponges or aggressive tools that could scratch the module surface.
  • To avoid possible thermal shock, clean the modules during early morning or non-Peak hour when module is cold.
  • Water pressure should not exceed 35 bar at the nozzle. Use of high-pressure hoses for cleaning may exert excess pressure and damage the modules. Use a nozzle to control the pressure of the water. 
  • Wipe the module from Top to bottom with running water. Rub wiper gently with module and dust will remove with water. Wiper movement should be from module top to bottom.
  • Start cleaning from the top row and work downwards. Use a soft-bristled brush or sponge to remove loose dirt, debris, or bird droppings. Wet the surface of the modules with water and then apply the cleaning solution using a soft-bristled brush or sponge. Allow the solution to soak for a few minutes, then scrub the surface lightly. Finally, rinse the modules with water.

How to decide Module cleaning Schedule?

The cleaning schedule can vary based on the site location, weather conditions, and the level of soiling. Develop a cleaning schedule based on the site-specific needs and environmental factors. If the soiling on module is more than you required to do more cleaning as compared to low soiling area.

What is the suitable time for Solar Panel cleaning?

The recommended time for cleaning modules is during low light conditions when production is lowest. However, when sun shines during the day, the panels also get heated up and cleaning solar panels with cold water in evening may result in thermal shock for panel which can permanently damage them which also called thermal damage. Hence, the best time to clean Solar Panels is early mornings, when the plant is not in operation, risk of electrical shock hazard is minimum and also temperature of solar panels is not high.

Which Cleaning agent used for Solar Panel Cleaning?

  1. A mild, non-abrasive, non-caustic detergent with deionized water may be used. Abrasive cleaners, Acid or alkali detergent must not be used because it will damage module reflective coating.
  2. Don’t use metal objects or harsh abrasive products for removing caked on materials – scratching the glass on a solar panel can affect its performance as scratches will cast shadows.

Conclusion

By following this Standard Operating Procedure (SOP), you can effectively maintain and clean your solar modules properly. Good module cleaning will definitely improve performance and also put good impact on module lifespan. It will reduce degradation percentage YOY.

What are the guidelines for cleaning solar panels?

1. During Wet cleaning, quality of water is crucial when cleaning solar modules. Hard water may cause defects on module as in long time frame you will observe water scaling due to deposition of high mineral content on glass surface. It will decrease module efficiency. So, it required to test your water frequently from Trusted LAB. If Hardness found more, then you can opt for RO system for Module washing. High mineral content water is not recommendable.
2. For Good Wet cleaning, you need to have good quality wiper or brush. Always use water & Sponge cloth for Cleaning. A mild, non-abrasive cleaning agent can be used to remove stubborn dirt. Do not use abrasive sponges or aggressive tools that could scratch the module surface.

Should Solar panel be cleaned regularly?

The cleaning schedule can vary based on the site location, weather conditions, and the level of soiling. Develop a cleaning schedule based on the site-specific needs and environmental factors. If the soiling on module is more than you required to do more cleaning as compared to low soiling area.

What chemicals are safe to clean solar panels?

A mild, non-abrasive, non-caustic detergent with deionized water may be used. Abrasive cleaners, Acid or alkali detergent must not be used because it will damage module reflective coating.


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