Solar panels, like other electrical devices, require regular maintenance for effective operation. The effectiveness of modules decreases with time as layers of dust accumulate on their surface. A household system of solar panels, which typically varies from 1 kW to 5 kW, can be manually cleaned with a wiper or brush. However, it can be challenging to manually clean every module on bigger commercial-scale solar projects. In this situation, there are two options for cleaning – hiring a workforce or using an automated system. Clearly, hiring a workforce is a costly and time-consuming process. This is the reason why the market share of robots that clean solar panels is rapidly rising.
Further, large volumes of water are used in solar energy projects for cleaning panels. For developers, cleaning solar modules presents a significant issue, particularly in arid regions with limitations on water. Therefore, the solar industry is striving to shift from conventional cleaning methods to a more efficient and less water-intensive solution such as dry or robotic cleaning. Several robotic technologies have entered the market, providing a more cost-effective alternative to manual cleaning of solar panels. Some more prevalent forms of robotic cleaning systems are module cleaning robots, driving robots and AI-enabled robots.
Advantages of robotic cleaning
Robotic cleaning could completely alter the cleaning industry if its adoption increases, along with the solar industry’s growth in scale. Robotic cleaning provides the additional advantage of requiring less human intervention, which has been a concern for solar players owing to the potential danger to workers’ lives when doing manual washing.
Robotic cleaning offers the fantastic additional feature of enabling real-time performance monitoring via a central management system. To notify the operating system at the control room of any faults, robots send alerts. The warning then causes a modification to the cleaning motion on panels. By shifting robots from one farm to the next, operators can alter the cleaning schedule.
Robotic systems are also useful in geographies where lack of water is a serious problem, or there would be significant water wastage. Furthermore, using groundwater for cleaning requires permission from authorities, which takes time and could delay installation. Robotic solar cleaning provides a ground-breaking, waterless approach to dust removal from panels. The industry needs this solution in order to increase the penetration of solar plant installation, while decreasing its reliance on water. Given these advantages, robotic cleaning of solar panels is catching the attention of solar plant owners.
Cleaning solutions
The manual cleaning approach is the most commonly used method of cleaning household solar panels. The cleaning is performed with a handle connected to a water hose and a brush that does not scratch the panel. This cleaning approach exposes operators to hazards such as stair climbing and rooftop climbing. If this work is conducted by a specialised company, it would require high investment since the costs of performing this type of cleaning are usually high. However, the past few years have witnessed the rise of many different technologies for cleaning solar modules that require less or no manpower. For instance, the Solarbrush UAV cleans photovoltaic (PV) panels from the air. It is a drone composed of four sets of propellers and a tail, which has a specific material to clean the panels. According to its developers, the only part of the drone that makes contact with the surface of the PV panel is its tail, which is the main advantage of using this robot, as with this feature, the chances of damaging the PV panel decrease.
The Ecoppia E4 is a fully autonomous robot that uses microfibre brushes to clean dust from panels. It is designed for large rows of panels in arid or sandy locations. The robot has a PV panel and battery on board to store energy. This enables the robot to clean at night and the panel’s location near the bottom of the rail makes it possible to clean the rail itself.
Robots made by the Italian company WashPanel clean arrays of solar panels by sweeping a vertical brush across panels in a horizontal motion. Its length can range from 1 metre to16 metres. In order to moisten panels during cleaning, the robot has a water hose attached. The WashPanel robot includes an interface through which the washing system may be programmed. It uses a battery system with an automatic load to execute the movement. Additionally, it features an anemometer, and voltage and rain sensors.
The NO Water Mechanical Automated Dusting Device (NOMADD) is a robot designed specifically to remove dust build-up from desert solar panel arrays without the use of water. The NOMADD robot has certain features, in addition to not using water to clean panels, including fully automated and remote-controlled operability, the capacity to withstand harsh conditions due to its durability and the ability to clean a variety of panels.
Besides the previously described robotic cleaning techniques, non-autonomous cleaning techniques are sometimes used to maintain solar panels. There are two ways to use these non-automated approaches, the first of which is using sprinklers. In dry places, sprinkler systems are frequently used to keep panels clean. It cleans the panels at a relatively low cost and has the same cleaning effect as rain.
Uptake trends
Fully automatic dry-cleaning robotic and semi-automatic robotic cleaning technologies are currently on the rise across the globe, displacing the manual variety. Fully automatic dry-cleaning robots must be taken into account while designing a solar asset. Early planning enables the asset to optimise the number of cleaning robots required and to incorporate any design requirements from the outset. This waterless cleaning method is more cost effective than wet cleaning and can even increase power generation because it minimises soiling loss.
Semi-automatic cleaning uses both robots and manual labour. When compared to fixed robots, which require many robots for each row of the PV tables, this sort of cleaning is shifted manually from one table to another, which lowers the cost. The reduction of two significant operations and maintenance costs associated with the plant once it is operational – water and labour – allows developers to increase their return on investment.
The fully automatic cleaning robot is the most efficient cleaning technique. However, a significant expenditure is necessary to completely implement this technology. Meanwhile, there is another issue in adoption of robotic technologies, that of manpower vs machines. However, contrary to common belief, this will not result in fewer employment prospects in the sector. Instead, managing operations and monitoring them will call for skilled workforce.
Outlook
The use of robotic cleaning solutions is gradually gaining traction and will become more cost effective as project sizes grow larger. Utility-scale developers and operators of solar parks prefer automated cleaning solutions since the expense of manual labour for cleaning panels increases with the project size. It might take some time before robotic cleaning totally replaces manual cleaning due to the low labour costs in some regions, but as the cost of these solutions falls, more developers are opting to use this innovative technology.
In addition, the dirt that is accumulated on solar panels has a direct impact on their effectiveness. The panels must, therefore, be cleaned on a regular basis in order for them to function at their maximum efficiency. Due to the fact that this is a cutting-edge development in the field of technologies for cleaning PV panels, a variety of cleaning products for different types of dirt have come into the market. However, dry cleaning is the most preferred alternative for solar parks, where sand and dust are primary sources of photon obstruction. Thus, water scarcity will cause the shift to waterless robotic cleaning inevitable.
Fortunately, local governments and developers are receptive to innovation and embracing new technology. In the coming months, the technology will likely acquire more pace, and perhaps we will see further robotic-related innovations that will become the standard for cleaning PV modules.
