Effect of dust pollutant type on photovoltaic performance Zeki Ahmed Darwish a , Hussein A. Kazem b,n , K. Sopian a , M.A. Al-Goul a , Hussain Alawadhi c a University Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia b Sohar University, PO Box 44, Sohar PCI 311, Oman c University of Sharjah, PO Box 27272, United Arab Emirates article info Article history: Received 21 July 2014 Received in revised form 18 August 2014 Accepted 26 August 2014 Keywords: Dust effect Photovoltaic Pollutant type Air pollution X-ray diffraction abstract Many environmental parameters affect the production of photovoltaic (PV) systems and dust could be one of the main reasons of degradation of PV panels. PV systems utilized in large and small scales accumulate different types of dust which reduce the efficiency. The dust contents, which represent a mixture of different pollutants, are specified by the geographical site. There are many studies focused on the effect of dust on PV performance but few studies have investigated the effect of dust pollutant type on the performance. Mainly, the effect of pollutant type has been investigated indoors and few outdoors. In the present paper the effects of pollutant types on the PV performance have been revised and experimented. A critical review and challenging questions have been developed for the researchers working in this field. & 2014 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................ 735 2. Position of dust-pollutant type problem ................................................................................. 736 3. Effect of dust pollutant type ........................................................................................... 737 4. Effect of pollutant type on current, voltage, efficiency and power ............................................................. 738 5. Comparison between effects of pollutant types ............................................................................ 742 5.1. Experiments related to natural dust (outdoor) ...................................................................... 742 5.2. Experiments related to artificial dust (indoor) ....................................................................... 742 6. Discussions and conclusions ........................................................................................... 742 Acknowledgment ....................................................................................................... 743 References ............................................................................................................. 743 1. Introduction Due to the fast development in economical and technological aspects, solar photovoltaic PV industry has been disbursed glob- ally. As a result of this development, the consumption of energy is increasing dramatically yearly because of development, demand of comfort and the growth of the world population [1]. Electricity is mainly generated by the use of a variety of sources such as fossil fuels which play a vital role in meeting the demand for energy. The impact of greenhouse gases (GHG) on the environment and global warming is enormous and arduous on the people. A suitable solution to reduce these effects and save the environment is the use of solar PV as a renewable energy source. In a PV, the sun light energy is absorbed by the semiconductors as photons after which they are converted into a voltage. The design of these solar-energy systems covers a set of wide-ranging materials science and engineering, as well as innovative approaches to lowering cost and increasing system performance [2]. In 1960, researchers conducted experiments on semiconductors (III–V and VI) while a new technology for polycrystalline Si (pc-Si) and thin film solar cell was established in order to lower the materials cost and energy input but increase the production capacity. 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.2014.08.068 1364-0321/& 2014 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ96899645363; fax: þ96826720102. E-mail address: h.kazem@soharuni.edu.om (H.A. Kazem). Renewable and Sustainable Energy Reviews 41 (2015) 735–744