Reconsidering the future of seawater desalination in China: Proposal of constructing short-cut water cycle in coastal areas

In a new study titled published in Water & Ecology, a research team led by Kaijun Wang from Tsinghua University re-evaluated desalination through a holistic perspective— integrating production costs, infrastructure investments, and environmental external conditions across the full lifecycle assessments compared with conventional water supply systems. The authors presented a new paradigm for water resource management—one that emphasizes technological innovation, economic feasibility, and environmental resilience to ensure long-term water security.

“China's water deficit was underestimated. Conventional water supply systems, such as reservoirs and diversions, are overwhelmed,” says Wang. “Groundwater over-extraction has led to critical aquifer depletion. Competing demands from ecological restoration and economic development, exacerbated by climate-induced saltwater intrusion, have created a hidden crisis that threatens regional water security and economic stability.”

The authors noted that seawater desalination presents a paradigm shift in water management, decoupling freshwater production from natural hydrological constraints, and posited that desalination transforms seawater into a manufacturable resource, thereby decoupling supply from natural hydrological cycles. 

“Global success in arid nations like Saudi Arabia and Israel demonstrates its viability for large-scale water security,” explains Wang. “By overcoming geographic and temporal limitations, desalination redefines water scarcity as a technical challenge solvable through infrastructure innovation and strategic pricing that reflects water’s true economic and ecological value.”

A significant “perception gap” regarding the cost of desalination is identified as a major barrier. “Technological advances, particularly in reverse osmosis, and economies of scale have drastically reduced costs,” adds Wang. “A comprehensive lifecycle assessment, including hidden environmental and social costs associated with conventional water supply systems, reveals growing competitiveness of desalination.”

Furthermore, integrating with renewable energy could reduce its carbon footprint by 57.5 to 98.3%, enhancing its economic and environmental viability.

To address China’s growing water scarcity, the authors proposed a “100-Kilometer Coastal Desalination for Short-cut Water Cycle (100K-CDS)” strategy that leverages China’s extensive coastline to industrialize water production. The goal is to create a manufactured, "short-cut" water cycle independent of natural watersheds to decouple water security from geographical constraints.

“This strategy is particularly vital for China's coastal regions, which support over 40% of the population and contribute to more than 50% of national GDP but face severe water stress and saltwater intrusion,” says Wang.

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Contact the author: 

Dr. Kaijun Wang, wkj@tsinghua.org.cn

-State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China

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