Water (1) Desalination

What to do when there is no fresh water nearby? either you make a long aqueduct to bring water from a distant source, or you use a desalination plant if salt or brackish water is at hand. This has been done in some parts of the spanish southeast coast. The Bajo Almanzora desalination plant brings water to an intensive cultivation area without need for long aqueducts.

With a production capacity of 20 cu hm of water per year and a 75,9 million euros investment (23 of which come from European funds), the 150.000 people and the farmers in the area access a more reliable water source than what is normally available in this dry area. Using an inverse osmosis technology, the factory ensures the brine (water with a much higher salt concentration that is discarded as a result of the desalination process) is brought to an environmentally adequate discharge point through a 2,5 km pipe (the sea is close to the plant, as you can see on google maps). The plant takes no more than 5 hectares on the ground.

I don’t know the accurate data on this plant, but if we take an average efficiency of 4 kwh of electricity for each cu meter of desalted water (an usual value for such plants), the yearly demand of 20 cubic hectometers would be 800 Mwh of electricity. With wind farms usually beyond 50 Mw of installed capacity, this can be done on renewable energies (altough it is not always the case, and a connection to the grid is needed for those days in which the wind is not blowing). As an example, a specific publication on the issue. 

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