Advances in approaches and methods for self-cleaning of solar photovoltaic panels

•Comprehensive summary on several factors affecting the solar panel efficiencies.•Compendium on different self-cleaning methods for PV panels.•Superhydrophobic based self-cleaning method is most suitable for PV applications.•Presents the future trend and move in self-cleaning based research on PV panels. Photovoltaic (PV) installations in desert areas such as Middle East, Africa, four-season countries and industrial areas suffers from loss in efficiency due to accumulation of dust, snowfall and airborne dirt (both organic and inorganic) from factories. The resultant soiling through dirt accumulation hinders the conversion of light into electricity, consequently degrading the PV performance. Hence, in order to maintain a steady performance, PV panels must be cleaned regularly. However, traditional manual cleaning of the panels is an energy and time consuming process. Moreover, manual cleaning can also create cracks on the PV panel surface due to harsh brushing which will further deteriorate PV performance. In addition, very small particles cannot be removed effectively by manual cleaning process. Therefore, researchers around the globe are promoting the self-cleaning methods, viz., electrostatic method, mechanical method and coating method for PV panel surface cleaning. In this article, attempt has been made to review the progress and achievements in all kinds of self-cleaning methods for PV panels with special focus on super hydrophobic coating based methods for self-cleaning. In this connection, future focus research areas such as development of mini robots and spray coating on self-cleaning have been pointed out.