A Review on Mobile Robots and its Design Requirements to Clean Solar Photovoltaic Modules

Solar photovoltaic energy has experienced growing interest as a renewable and sustainable source in contrast to conventional fossil fuel-based energy. Households, businesses and government institutions have invested in the installation of solar PV panels due to their smaller footprint and the significant savings in electricity consumption they offer. Despite the benefits of solar PV, the accumulation of dirt on the glass surface of solar panels, such as dust and other contaminants, reduces their efficiency by obstructing the amount of sunlight reaching the PV cells, affecting their power generation capacity by 20% and damaging the cells or shortening their lifetime. Therefore, maintenance and cleaning of solar panels is crucial to avoid future problems and to ensure efficient production of electrical energy. This is why different researchers and companies continue to search for new ways of cleaning PV modules. Since the nature of this task is costly and high-risk, specialised services are required for monitoring and cleaning solar photovoltaic panels. In this context, specialised mobile robots have been developed, which perform cleaning and analysis of solar panels in an automated way. This review focuses on analysing and comparing various mobile robots used for automated solar panel cleaning, including their characteristics, advantages and limitations. The aim is to identify the most promising technologies and possible areas of improvement to encourage wider adoption of these automated systems in the maintenance of solar photovoltaic installations. Moreover, recommended design requirements for these type of robots are listed. By facilitating access to an efficient and low-cost cleaning service, it is expected that more households and businesses will be able to maintain their solar panels in adequate condition, thus ensuring a continuous and efficient production of electricity.