Metamodeling life cycle assessment to explore interactions in the water-energy nexus of desalination processes

The relationships within the Energy-Water nexus are inherently complex, necessitating sophisticated methods to optimize and manage these interactions effectively. Metamodeling emerges as a crucial technique in abstracting these complex relationships into a manageable analytical form. This study adopts a systematic approach to construct Life Cycle Assessment (LCA) metamodels, aimed at examining the interactions within the water-energy nexus of various desalination technologies. A critical aspect of the developed methodology is the selection of sampling points that align with LCA scenarios through a tailored designed experiment (DoE) model. These scenarios, which include Reverse Osmosis (RO), Electrodialysis (ED), and Multi-Effect Distillation (MED), are evaluated using a set of indicators the Energy-Water nexus, across tradeoff nexus policies. The results signify the impact of considering the Energy-Water Nexus on optimizing desalination processes, compared to evaluating energy and water metrics independently. In policies where nexus considerations were not integrated—focusing solely on cumulative energy or exclusively on water footprint—the RO with Wind Turbine (RO[WT]) scenario emerged as the optimal solution. This configuration consumed 7.540 MJ and 1.654 m³ of water and a carbon footprint of 0.719 kg CO₂eq per cubic meter of desalinated water. Conversely, policies that incorporate a nexus approach favor the adoption of MED with Thermal Solar (MED[TS]) scenario. Characterized by its moderate energy consumption of 2.226 MJ, and a water footprint of 2.226 m³, per cubic meter. These findings illustrate the critical role of employing Energy-Water Nexus frameworks through metamodeling in minimizing the environmental impacts associated with desalination processes.