Mapping inland global solar desalination demand using an updated global salinity dataset and geospatial multicriteria analysis

The global demand for inland, solar-powered water desalination technology is rapidly evolving, driven by increasing water scarcity, climate change, and population growth. However, this demand, especially in Low- and middle-income countries, remains poorly quantified due to the lack of comprehensive global data and analysis of these regions. This study aggregates and interprets data using diverse computational methods to create a high-resolution global map identifying locations of high potential for inland, solar-powered water desalination. To the authors’ knowledge, we compiled one of the most extensive inland water salinity datasets to date – exceeding 1.1 million georeferenced points – and analyzed it alongside several key localized metrics including water stress, population density, solar irradiance, water cost, and electricity prices. By benchmarking five different statistical and machine learning approaches side-by-side, we developed a holistic feasibility score for solar desalination, identifying high-potential areas in regions including Africa, the Middle East, South and Southeast Asia, Central America, Mexico, and southern Europe at 1-degree spatial resolution. Our binning methodology revealed that approximately 22% of global land area shows high feasibility scores, with peak values concentrated in the Middle East, Western Africa and Northern Africa regions. The Top 6 regions displayed a mean desalination feasibility score (using binning method) of 77.7%, which was approximately 50% higher than the feasibility score of 51.8% for the Rest of the World. This research provides an updated pointwise global groundwater salinity dataset, novel geospatial multicriteria computational methods, and new insights into global solar desalination potential via a high-fidelity map.