Unlocking synergies between seawater desalination and saline gradient energy: Assessing the environmental and economic benefits for dual water and energy production

The global scarcity of fresh water has increased the desalination systems' importance. Although these systems face certain limitations, significant efforts are being made using renewable energy sources like Saline Gradient Energy (SGE). This led to the emergence of two technologies: Pressure Retarded Osmosis (PRO) and Reversal Electrodialysis (RED). Hence, this innovative study aims to contrast the potential environmental and economic benefits by performance of PRO and RED integration into desalinating seawater by Reverse Osmosis (SWRO). We comprehensively assessed their life cycle using SimaPro® software and conducted a stochastic economic evaluation to achieve this. For the calculation basis, the systems were dimensioned using Wave® software and theoretical-analytical methods based on technical literature. Our findings revealed SWRO-PRO is cheaper (1.49 USD/m3), less energy-intensive (4.602 kWh/m3), and more environmentally friendly than SWRO (emission reductions in the following categories: 10.31% human health, 11.79% ecosystem quality, and 11.44% natural resources depletion). SWRO was the second-best option with moderate costs (1.53 USD/m3), energy requirement (5.569 kWh/m3), and environmental impacts, while SWRO-RED was the least favorable, with higher costs (1.83 USD/m3), energy consumption (5.573 kWh/m3), and environmental impacts (increases of 22.20%, 21.02%, 15.2%, 22.2% of mentioned categories, respectively). PRO integration represented an enhancement, and despite lower benefits, RED maintains a substantial future potential. Thus, this study is a unique holistic approach that integrates environmental and economic considerations and endeavors to revolutionize our understanding of synergistic water-energy systems. Therefore, this pioneering research could pave the way to address global water scarcity and clean energy challenges.