Sustainability assessment of electrodialysis powered by photovoltaic solar energy for freshwater production

Membrane desalination does help at procuring an increasing freshwater (FW) global demand. Energy requirements of desalination technologies compromise the environmental sustainability of desalination. The integration of renewable energies with desalination technologies might improve the sustainability of desalinated water over other alternative RV sources. This paper discusses the sustainability of Electrodialysis (ED) powered by photovoltaic solar (PV) energy as one of the most promising configurations for the desalination of brackish water. Environmental, with special focus on energy consumption as a function of salinity, economic, and social issues have been considered and main figures for an ED-PV case study in the Canary Islands focused in FW production are given. Energetic considerations have also been deeply discussed in the section of environmental issues. Reverse Osmosis has been taken as the reference technology. The reference energy consumption for ED of brackish water (2500-5000 mg L-1) includes a range of 0.49-0.91 kW h m(-3). Due to this range and regarding to the environment, the use of ED-PV is in the range of 0.02-0.03 kgCO(2) m(-3) (only due to energy supply), which is a decrease of one order of magnitude compared to grid mix supply. A medium-term forecast for ED-PV is presented in which might be economical over conventional grid mix supplied ED before 2020 under the most optimistic scenario, leading to a production costs around 0.15-0.4 (sic) m(-3). With respect to social issues, renewable desalination contributes to a significant increase of local direct and indirect employment but under a wide range of 0.1-4 permanent positions per 1000 m(3) day(-1). Finally, the main identified barriers for ED-PV preventing a larger market penetration are the matching of the intermittent output of renewable energies with water demand, lifetime of membranes, efficiency of solar panels and the high production cost of freshwater compared to its low market price as commodity. (C) 2015 Elsevier Ltd. All rights reserved.