Spain has 765 desalination plants, which produce around 1,800 hm³ of water per year, according to figures provided by the Spanish Association of Desalination and Reuse (AEDyR), which already places the country in fourth place in the world in terms of total capacity. installed. This production volume represents close to 6% of the total estimated demand, which is around 32,000 hm³, according to data from the Ministry of Ecological Transition and Demographic Challenge. However, as Belén Gutiérrez, a member of the board of directors of said association, points out, this same ministry also «calculates that climate change has caused a loss in water availability of 1,300 cubic hectometers annually since 1980.» This data is a reflection of the situation in which water resources find themselves, which will be “insufficient in the medium term for the uses required by our socioeconomic development,” says José Claramonte, general director of Facsa. So much so that the recent Study on the water management model in Spain, published by this company, places the territory as “the third in the EU with the greatest water stress” in terms of fresh water extracted with respect to renewable resources. And the outlook is not rosy: another report, prepared by the European Commission and published in 2020, corroborates that almost half of the Spanish population (22 million inhabitants) resides in regions with water stress, calculating that seven million more will join this figure in 2100 if the worst climate warming scenario comes to pass; that is, an increase of 3 °C in the average temperature. To compensate for this situation, Gutiérrez points out, “the desalination of seawater is proposed as the solution to increase the availability of the resource and cover existing and future demands.” In his view, the use of desalination not only addresses current shortages, but also strengthens long-term water security, as plants provide a source of water beyond natural resources. Added to this is that it is not affected by climate variability, as confirmed by Francisco J. Baratech, president of Acuamed, who highlights that “the main benefit of desalination is the guarantee of supply of quality water, which is essential in periods of drought.”Two circumstances that intervene in the future of these systems are, on the one hand, the geographical configuration of Spain and the distribution of the population with respect to the sea. On the other hand, the “strong investment already made” in desalination plants in our country—which had a boom in the eighties and nineties—and which, “in many cases, have a wide margin for improvement in their performance,” explains Claramonte. . A reality that «could represent an immediate response in emergency cases», as is experienced in certain Spanish regions. Even so, all experts agree that, being part of the solution, desalination is not the main answer to the water problem in Spain. What happens, first of all, is to optimize the use we make of it; And, says Ricardo Sáez, general director of Sitra, only the distribution networks cause losses «of 20% of the water that flows through them and, in the case of certain population sizes, up to 60%.»Carboneras desalination plant (Almería). PHOTO COURTED BY INIMA
Generation on demand
In addition to security of supply, another key aspect that Gutiérrez adds is that «current technology allows the production of water on demand, adapted to the quality for human consumption, irrigation or industrial use.» An element that influences the energy consumption of these plants and whose importance derives from the fact that approximately 80% of the water demand in Spain corresponds to the agricultural environment, followed by urban supply, which represents 15%. In this sense, declares Antolín Aldonza, spokesperson for the Board of Directors of the Spanish Association of Water Technology Companies (Asagua), “we are a rarity on a global scale”, while more than 20% of the desalinated water produced in Our country is dedicated to agriculture, “and if we take into account only the data from the Mediterranean, the percentage rises to almost 60%.” Precisely in relation to the sea, Aldonza points to one of the great challenges, which is the management of waste, more specifically, brine. The water rejected from a desalination plant “reaches concentrations greater than 70 grams of salt per liter (twice that of seawater) and usually ends up back on the coast,” he details, which is why it needs to be treated to prevent it from affecting the marine environment. . The use of new techniques, such as computational fluid models, help manage this brine to minimize its environmental impact, although solutions are being developed to convert this waste into a resource.
The challenge of sustainable consumption
Desalination has experienced a great improvement in efficiency since its introduction in Spain in the sixties. If then the cost per 1,000 liters of water “ranged between 3 and 4 euros, today it is between 0.50 and 0.8,” indicates Silvia Gallego, from AEDyR. This figure includes the amortization of infrastructure, as well as operation, maintenance and energy costs; and it is getting closer to the price of drinking water, in part, because it has increased, “since drinking water sources are more contaminated.”
Given the high electricity consumption of these facilities, the sector is taking measures to use renewable energy directly. This is the case of Acuamed, which – using funds from the Recovery, Transformation and Resilience Plan – “is implementing projects to provide plants with photovoltaic panels,” says its president, Francisco J. Baratech, the most recent example being those of Torrevieja. and Águilas, which will be in charge of its expansion.