Water scarcity concerns along Spain’s coast have prompted experts to weigh the sustainability of desalination against water conservation and demand management. They note that while desalination plants can provide a steady supply, high operating costs in certain regions and potential impacts on marine ecosystems challenge its long-term viability compared with more efficient water use and public awareness campaigns.
Data from ZINNAE, an Aragonese cluster focused on efficient water use, shows Spain hosts a total of 765 desalination facilities. The majority are situated in the Levante and island regions, with some plants being temporarily halted when the economics do not support operation.
The elevated price tag is largely due to electricity needs. Thermal methods require substantial energy to heat seawater, and even modern approaches to producing one cubic meter of desalinated water can consume roughly 4 kWh of energy.
There are a total of 765 desalination plants in Spain, mainly in the Levantine region and on the islands.
Reverse osmosis, the prevailing desalination technology, faces wear if utilization is inconsistent. When demand drops, continued operation becomes costly, making it impractical to match production with water needs purely on energy and equipment expenses.
Beyond price, ecological effects are a concern. Desalination generates highly saline brine which can harm underwater life, a consequence not easily offset by other gains.
Despite these drawbacks, desalination remains vital in island contexts lacking local freshwater resources. For example, Gran Canaria is frequently cited as an area with a notably high concentration of desalination plants per square kilometer, according to Emilio Custodio, an engineering industrialist at the Polytechnic University of Catalonia.
Boron problem in agriculture
The main hurdle isn’t urban supply but agriculture, which consumes large amounts of water and often refuses to pay premium prices for it. In plants that do not run year-round, desalinated water can cost more than 2 euros per cubic meter, a rate that many farmers find prohibitive.
There is a caveat: while desalinated water is usable, its boron content can be too high for certain crops. As a result, farmers commonly blend it with transfer water or groundwater to mitigate salinity challenges.
ZINNAE notes that although only about 3% of desalinated water is used for agriculture globally, this share rises to roughly 23% in Spain. Expanding agricultural use would demand substantial energy for treatment, brine management, and logistics, all carrying economic and environmental costs.
Additionally, coastal experts warn that increased intake of desalinated water could harm marine habitats. For instance, higher salinity levels risk damaging seagrass meadows such as Posidonia, which cannot tolerate very high salt concentrations for extended periods.
Beyond ecological concerns, simply increasing water availability through desalination could spur higher consumption, potentially exacerbating overall resource strain. Ecologists argue that continuous desalination should not be treated as a default supply solution, except in isolated island contexts where alternatives are limited. Canary Islands are often cited as a necessary exception in certain cases.
Overall, water managers note that overall usage in Spain accounts for a large share of demand, and they stress that desalination should be considered a last resort for keeping drinking water supplies secure. A shift toward water-saving practices and public awareness remains essential to addressing scarcity and reducing dependence on desalination as the primary supply method.
To confront resource scarcity, ZINNAE advocates a fundamental shift in how water is valued and used, especially relative to other resources that are often undervalued because of low energy costs. The aim is to prioritize conservation and smarter use rather than expanding desalination unchecked.
In conclusion, saving water and educating the public about responsible use are regarded as critical tools in addressing scarcity. This issue involves consumers across households, industry, tourism, commerce, and agriculture.
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For more information on strategies and policy directions, contact the environmental department through the appropriate channels and seek reputable sources of data to stay informed about the evolving landscape of water management in Spain and North America.