Desalination xxx (xxxx) xxx Please cite this article as: Bijan Rahimi, Desalination, https://doi.org/10.1016/j.desal.2020.114885 0011-9164/© 2020 Elsevier B.V. All rights reserved. A feasibility study of solar-powered reverse osmosis processes Bijan Rahimi a, * , Hamed Shirvani b , Ali Asghar Alamolhoda a , Fathollah Farhadi b , Mohammadreza Karimi b a Institute of Water and Energy, Sharif University of Technology, Azadi Ave., Tehran, Iran b Department of Chemical and Petroleum Engineering, Sharif University of Technology, Azadi Ave., Tehran, Iran HIGHLIGHTS • Impacts of energy recovery devices, batteries and permeability have been evaluated • The scenario where all the PV power is exported to the grid has the highest NPV • Using energy recovery devices is not economically viable in each scenario • For discount rates higher than 23%, there is no room for PV-RO desalination plants • The worst scenario is the one that uses batteries A R T I C L E INFO Keywords: Desalination Reverse osmosis Solar desalination Photovoltaic Renewable desalination Solar powered ABSTRACT The use of solar-powered reverse osmosis desalination systems is a sustainable and environmentally friendly solution in the desalination industry. However, there are some substantial technical and economic challenges due to the intermittency and fuctuation of solar energy. Recent technological improvement and feed-in tariff policies enable these systems to be competitive with conventional grid-connected reverse osmosis systems. In this paper, a feasibility study of the integration of solar panels with the grid to power small-scale reverse osmosis systems (namely up to 2000 m 3 /day) is conducted in Iran, as a country with a low price of electricity. For this purpose, a city located on the northern coast of the Persian Gulf, which deals with water shortage but has high solar ra- diation, is selected as a case study. Five different scenarios are considered, and the impacts of the use of energy recovery devices, energy storage systems and membrane characteristics have been studied. Finally, a detailed cash fow analysis is provided for each scenario. In the end, we show the economic viability of solar-powered reverse osmosis plants when their unused or surplus solar electricity is exported to the grid. 1. Introduction A 50% increase in the global online desalination capacity over 6 years from 66.4 million m 3 /day in 2012 to 99.7 million m 3 /day in 2018 highlights the importance of this industry, especially in arid and semi- arid zones such as the MENA region with around 60% of the desalina- tion capacity worldwide [1–4]. There are presently 21,123 desalination plants online and produce the daily needs of more than 300 million people around the world [3]. The Arab states of the Persian Gulf are the world’s largest producers of desalinated water and produce about 40% of the total desalinated water in the world [1–3,5,6]. There are different methods for water desalination, which are broadly classifed as either desalination ‘with’ or ‘without’ phase changes (depending on the separation process used). Multi-Stage Flash (MSF) and Multi-Effect Distillation (MED) are the most economic ‘with phase change’ desalination processes, and Reverse Osmosis (RO) is the most widely used ‘without phase change’ desalination process. In addition to the abovementioned conventional and commercial desali- nation processes, there are some other technologies which most of them are currently under research and development, such as HD [7,8], MD [9,10], CDI [11,12], Freezing [13,14], FO [15,16], AD [17,18], etc. In the Middle East, around two-thirds of the desalinated water pro- duced is from fossil fuel-based thermal desalination, while the rest is from reverse osmosis that relies heavily on electricity produced using natural gas [19]. Using thermal desalination processes in the Persian Gulf region is because of the long background of thermal processes and co-generating power and water, availability of lower-cost fuel, and the * Corresponding author. E-mail address: bijan@sharif.edu (B. Rahimi). Contents lists available at ScienceDirect Desalination journal homepage: www.elsevier.com/locate/desal https://doi.org/10.1016/j.desal.2020.114885 Received 19 June 2020; Received in revised form 31 October 2020; Accepted 24 November 2020