Is It Safe To Step On Photovoltaic Panels For Cleaning Work?

The Hidden Risks of Walking on PV Modules

 

PV modules are designed to withstand environmental forces like wind, snow, and hail; however, they are not built to take concentrated pressures from human foot traffic or walking on them. Even the most insignificant amount of pressure, can cause micro-cracks in the solar cells. These minor fractures can deprive the panels' integrity, both structurally and electrically, and develop into, "hot spots" which reduce energy output and accelerate the module degradation. Even if the module is not visibly damaged, it can violate the warranty under "abuse." In some instances, if the physical damage is severe enough, they will void the warranty and you will have to pay the replacement cost.

Industry standards like, GB/T 44264-2024, which is a national standard for PV cleaning robots in China, all stipulate to avoid making physical contact with the module, meaning walking on the surface, during maintenance. The procurement requisites for a cleaning service, when written by CECEP Solar Energy, includes, 'Do Not Walk on Modules', to protect them.

In addition to damage to the equipment, walking on PV panels causes a huge safety risk:
 Electrical Hazards: Damaged panels or defective wiring can result in electric shock. While cleaning, it is very much easier to electrically shock someone through the use of water.
 Physical Injuries: Workers can slip or fall when on sloping roofs or wet surfaces. In many instances, aluminum frames and/or mounting systems have sharp edges that can cause injury.
 Unstable Footing: Panels that are mounted on roofs or uneven ground may not bear human weight very well. There will be a risk of falling if the panel, or whatever the worker may be standing on, does not support the workers weight.

The industry is addressing these issues with a move to safer and more efficient cleaning practices:
1.Drone Technologies: Companies like Zhedian (Ningbo) Smart Energy are deploying drones to clean large-scale solar farms via high-pressure water jetting; one drone cleaning 1 MW (roughly 2,000 modules) of panels per day with reduced man-hours and risk.
2.Robotic Cleaner Technologies: Now supported by the GB/T 44264-2024 standard, there are various autonomous cleaning robots. These robots either clean without water in arid regions or use soft brushes that do not damage surfaces.
3.Manual Cleaning Protocols: When cleaning needs to be done manually, workers should use soft brushes, gentle water flow and safety harnesses. Cleaning should be performed outside of peak sunlight hours to mitigate thermal stress to panels.

Regular cleaning is vital to PV efficiency. Dust and debris can negatively impact energy output by between 5-25% depending on weather conditions. However, incorrect cleaning not only neglects maintenance but also may further reduce efficiency. For example, a study in Northwest China found that their automated cleaning robots increased efficiency by 15-20% could decrease labor costs by 50% compared to regular manual methods.

As the industry continues to push for renewable energy, more efficient ways of maintaining equipment will be required. Autonomous cleaning technologies, such as drones and robots, will not only improve safety but help integrate sustainable practices, such as water conservation, while also minimizing down time. Further, according to Sun Hejie, the director of operations at Zhedian Smart Energy, "Automation is the future of PV maintenance; it will not only help with efficiency but safety".

Walking on PV panels for cleaning is a risky practice that jeopardizes both workers and equipment. It is not worth it and the Industry is adopting automated technology, and following stringent safety protocols to protect assets and prolong the life cycle of any solar energy system. Therefore, the transition to renewable energy is growing as standards such as those outlined above become paramount for sustainability.