Transboundary and National Environmental Impacts of Seawater Desalination in Central Chile: An LCA-Based Analysis Across Energy Transition Scenarios

The environmental impact of seawater reverse osmosis desalination in central Chile was assessed using Life Cycle Assessment (LCA) with the EcoInvent database to address the region’s high water stress. The study analyzed the operational phase using 1 m3 of product water as the functional unit, considering power demand, chemicals, and membranes across eight scenarios that varied energy matrix composition, membrane lifespan, water use, and seawater source. Eighteen environmental indicators were evaluated using the ReCiPe 2016 Midpoint (H) method. Results revealed that eight impact indicators were primarily national in origin, while ten exhibited transboundary characteristics. Power demand was the dominant contributor, exceeding 75% of impacts in 17 of 18 categories. A 25% power increase raised environmental impacts by an average of +21.5%, while the projected 2050 renewable energy scenario showed substantial reductions averaging −43.0%. This demonstrates that power consumption is the principal driver of environmental impacts, underscoring the importance of energy-efficiency measures and integration of Non-Conventional Renewable Energies (NCRE), particularly as fossil-based sources constitute the main contributors to environmental burdens at both national and transboundary scales.