An assessment of energy storage options for large-scale PV-RO desalination in the extended Mediterranean region

Seawater desalination is already a largely adopted option to cope with the scarcity of natural water resources, but the increasing concerns about water availability in the future make it even more attractive. Because desalination is a highly energy-demanding process, its coupling with renewable energy sources is an essential step for the sustainable production of desalinated water at large scales. In this work we analyze the potential to deploy large-scale seawater desalination using reverse osmosis (RO) under the hypothesis that all the required energy is provided by photovoltaic (PV) production. A simulation over the extended Mediterranean area shows that securing desalinated water for up to about 200 million people in the region is technically possible using PV only, and the benefits of energy storage in batteries and/or water reservoirs are usually higher than its costs. This suggests that water management policies could consider desalination more broadly and encourage PV-based RO, as a possible win-win and cost-effective strategy to improve water and energy resources security.