3E assessment of a solar-driven reverse osmosis plant for seawater desalination in a small island of the Mediterranean Sea

Water scarcity in many regions of the world and global demographic growth make the desalination of seawater and/or brackish an effective solution to meet the growing demand for fresh water. Nowadays, reverse osmosis has the largest share of the global installed desalination capacity. The impelling need to reduce greenhouse gas emissions has been pushing the search for sustainable technologies to produce the electricity needed to power reverse osmosis plants. Among solar technologies, little attention has been paid to the possibility of powering reverse osmosis with electricity from the dish-Stirling solar concentrator. To fill this knowledge gap, this paper assesses the energy-saving potential of a reverse osmosis plant coupled with a cogenerative dish-Stirling concentrator on a small island in the Mediterranean Sea. A model of the integrated systems was developed based on data measured on a real dish-Stirling concentrator. Moreover, the variation of the energy consumption of the reverse osmosis plant with the temperature of the feedwater solution was also accounted for. Hourly simulations showed that almost 36% of the annual water demand could be covered by driving the plant using electricity from the concentrator, and the solar fraction of the electricity consumed by the reverse osmosis plant accounted for 48%. Finally, economic and environmental analyses revealed that the levelized cost of water of €1.08 per cubic meter of fresh water, consistent with the literature, and the system could avoid emitting 34.16 tons of carbon dioxide equivalent emissions per year.