Power loss due to soiling on solar panel: A review Mohammad Reza Maghami a,b,n , Hashim Hizam a,b , Chandima Gomes a , Mohd Amran Radzi a , Mohammad Ismael Rezadad c , Shahrooz Hajighorbani a,b a Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia b Centre of Advanced Power and Energy Research (CAPER), Universiti Putra Malaysia, 43400 Selangor, Malaysia c Department of Mechanical Engineering, Faculty of Engineering, University of Malaya (UM), 50603 Kuala Lumpur, Malaysia article info Article history: Received 7 December 2014 Received in revised form 31 December 2015 Accepted 13 January 2016 Available online 30 January 2016 Keywords: Photovoltaic Losses Environment Power output Performance loss Shadow abstract The power output delivered from a photovoltaic module highly depends on the amount of irradiance, which reaches the solar cells. Many factors determine the ideal output or optimum yield in a photovoltaic module. However, the environment is one of the contributing parameters which directly affect the photovoltaic performance. The authors review and evaluate key contributions to the understanding, performance effects, and mitigation of power loss due to soiling on a solar panel. Electrical characteristics of PV (Voltage and current) are discussed with respect to shading due to soiling. Shading due to soiling is divided in two categories, namely, soft shading such as air pollution, and hard shading which occurs when a solid such as accumulated dust blocks the sunlight. The result shows that soft shading affects the current provided by the PV module, but the voltage remains the same. In hard shading, the performance of the PV module depends on whether some cells are shaded or all cells of the PV module are shaded. If some cells are shaded, then as long as the unshaded cells receive solar irradiance, there will be some output although there will be a decrease in the voltage output of the PV module. This study also present a few cleaning method to prevent from dust accumulation on the surface of solar arrays. & 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Contents 1. Introduction ....................................................................................................... 1307 2. Critical studying in dust ............................................................................................. 1309 2.1. Cause of dust accumulation .................................................................................... 1312 3. Shading by soiling on PV performance .................................................................................. 1312 3.1. Partial shading of PV module by a soil patch ....................................................................... 1312 3.1.1. The effect of soft shading and hard shading on module performance ............................................ 1313 3.1.2. The effect of soft shading and hard shading on array performance .............................................. 1314 4. Dust removal from PV (Solution) ...................................................................................... 1314 5. Conclusions ....................................................................................................... 1314 Acknowledgement...................................................................................................... 1315 References ............................................................................................................ 1315 1. Introduction Solar energy, which comes from the sun in the form of solar irradiance, can be directly converted to electricity by using photovoltaic (PV) technology. PV technology uses solar cells made of semiconductors to absorb the irradiance from the sun and convert it to electrical energy. Currently, solar energy has drawn worldwide attention and is playing an essential role in providing clean and sustainable energy [1]. However, the research related to the nature of semiconductors, which are used in solar cells, has limited the efficiency of PV systems to 15–20%. Thus, in order to increase the efficiency of the PV system, some improvements such Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/rser Renewable and Sustainable Energy Reviews http://dx.doi.org/10.1016/j.rser.2016.01.044 1364-0321/& 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). n Corresponding author at: Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia. E-mail address: Mr.maghami@gmail.com (M.R. Maghami). Renewable and Sustainable Energy Reviews 59 (2016) 1307–1316