Uncovering the advantages of manual, mechanised and robotic solar panel cleaning

06/10/2020

Photovoltaic panels are protected by resistant fiberglass that safeguards the panels from exposure to the atmosphere, including even the worst hailstorms. But, for solar systems to perform optimally, the panels need to be cleaned regularly.

Companies with solar panels plants or farms can choose between manual, mechanised and robotic cleaning solutions, depending on the size and set up of the system. The following information looks at the advantages of manual, mechanised and robotic solar panel cleaning solutions.

Manual solar panel cleaning solutions – ensuring visual system health monitoring

Regular manual solar panel cleaning using trained cleaning teams, the right materials, and the correct cleaning techniques, helps to optimise the output performance of the panels. But more than that, manual cleaning puts the cleaning team at the grass roots of the solar system. A hands-on cleaning team can help identify and remedy potential fire safety issues, hot spots, pests and other potential issues like crazing (webs of small cracks) and delamination (peeling off of laminate layer), to help protect the investment in and extend the life of the system. The manual cleaning process uses water, and while it is uncomplicated, it is time consuming and expensive due to the labour costs.

  • Equipment: Specialised cleaning companies that offer solar panel cleaning services have purpose-built vehicles fitted with the necessary equipment to clean ground and roof installations. The setup would typically include self-contained water tanks in varying sizes, ~100-meter hose reels with water-fed pipes, extension poles and brush heads. The cleaning of roof installations requires equipment for working at heights, including condition-certified ropes, harnesses and ladders. All cleaning staff should wear appropriate personal protection equipment to match the site’s requirements.
  • Cleaning capacity: Depending on the location of the site, the time of day, the temperature and the condition of the panels, a 500-litre water tank will typically clean between 500 and 1,000 panels in a day using two teams of three cleaners.
  • Type of installation: Manual cleaning is practical for smaller installations of up to about 5,000 rooftop panels at office parks, shopping centres, industrial, educational and medical facilities, etc. In particular, its best for rooftop installations, where the installations are across multiple buildings with different roof sections, or where working conditions are tight and require agile teams to complete the cleaning requirements.

Mechanised solar panel cleaning – considering the scale factor

It is more cost effective and faster for larger, ground solar panel installations to use mechanised cleaning. To illustrate this point, a manual cleaning service that performs cleaning services on 1,000 solar panels twice a year, will cost approximately the same price as mechanised cleaning every six weeks. Regular cleaning means less variation in the output performance of the panels. In addition, mechanised cleaning provides the option for wet or dry cleaning, with or without suction, delivering possible savings in water consumption.

  • Type of installation: Mechanised cleaning is fast and effective for large, ground-based solar farms with more than 5,000 panels. Sufficient driving space in between the panels and turning space at the end of each table is required to ensure panel accessibility by the machine.
  • Cleaning capacity: Mechanised solar panel cleaning systems can clean between 800 and 1,500 panels per hour.
  • Equipment: Companies, like BP Metalmeccanica, produce purpose-built solar panel cleaning machines for solar farms. The series of operator/driver machines/tractors are designed to eliminate any type of dirt from photovoltaic systems using various accessories, including a hydraulic / telescopic arm, wet (foam) and dry (nylon) spinning brushes up to 6.5 meters long, brooms, suction systems and high-pressure water hoses. The water system consists of a tank with a capacity of 2,100 litres with pump capacity of 40 litres per minute. An additional high-pressure pump can be used both for cleaning the machine itself and for cleaning the panels. The machines are installed on a tracked undercarriage and both the machines and their configuration can be customised in terms of characteristics and dimensions. They are versatile and suitable for various environments, including desert areas.

The following video clip illustrates the versatility of mechanised solar panel cleaning:

Self-operating robotic solar panel cleaning systems

Solar-powered robots provide a revolutionary, water-free, autonomous solar panel cleaning solution for large solar panel farms. The robotic cleaning systems are expensive to install and to maintain, but they operates autonomously with limited human intervention, saving on labour, water and fuel consumption.

  • Type of installation: These solar-powered robotic systems are best suited to large solar plants that fix a robotic system to each row, or table. The robots travel along the table, irrelevant of their height, providing daily cleaning to optimise the plant’s energy output. They work effectively in most environments, including deserts to combat daily dust build up.
  • Equipment: The solar-powered robotic cleaning solution includes a winch system that moves dry, micro-fibre brushes up and down the panels in a smooth motion with no load on the panel surface. The system uses gravity and the tilt of the panel to brush any dust downwards and off the panel. These robotic cleaning systems use one robot per table. Centralised management via a web-based dashboard enables performance monitoring in real-time and uses mobile alerts to communicate any issues with an operator directly to their smart device. Partly mechanised systems are also available that are more cost-effective. The remote controlled units use an operator to guide the cleaning motion up and down the panels. As these systems are not fixed to the solar panels, the operator can move the robots from one table to the next, sharing the cleaning capacity across the solar farm. Labour costs would remain a consideration as the system set up would dictate the amount of human intervention required.
  • Cleaning capacity: A robotic solar panel cleaning solution cleans in the early morning or late afternoon to minimise shadows on the panels during sunlight hours. The system, with a robot installed on each table, can clean the entire installation every day.

The following video clip illustrates the versatility of mechanised solar panel cleaning:

The following table summarises the pros and cons of the three solar panel cleaning systems to help you to make the right decision for your solar system.

DetailsManualMechanisedRobotic
Cleaning typeWetWet, dry with or without suctionDry
Human interventionCleaning teamsOperator/driverAutonomous with limited human activity
CostHigh labour costInitial outlay, cost effective to maintainExpensive to install and maintain
Time consumptionTime consumingTime efficientFast
Water consumption500 litres per ~500 to 1,000 panels500 litres per ~500 to 1,000 panelsNone
Cleaning intervalTwo or three times per year6-8 weeklyDaily
CostOPEXCAPEXCAPEX
InstallationAny installation types, up to 5,000 panelsGround installations with sufficient space between and at the end the tablesGround or roof installation, no space between tables required

See how quickly we can help you African Corporate Cleaning enables effective cleaning of solar panel installations. We have the right solar panel cleaning services for you to help keep your systems operating optimally. Contact us for fast assistance: https://www.africancorporatecleaning.co.za/contact.html

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