Drought-hit Barcelona quenches its thirst with expensive desalination

EL PRAT DE LLOBREGAT, Spain (AP) – Where once Barcelona’s population drank mainly from its rivers and wells, Spain’s second city now relies on a labyrinthine web of green, blue and purple pipes to interior of an industrial plant to keep him from getting thirsty in the midst of a prolonged drought.

Water is pumped from two kilometers (1.2 miles) into the Mediterranean Sea to where the Llobregat desalination plant sits on a secluded beach. After passing through several cleaning and filtering systems, it reaches its final stop: the twisting and turning multicolored channels that squeeze every drop of water without its salt.

Barely used after its construction in 2009, Europe’s largest drinking water desalination plant is running at full speed to help the greater Barcelona region and some five million people adapt to the impact of climate change , which has contributed to the drying up of freshwater in southern Europe. water reserves from heat waves and drought.

In April 2021, before the drought, rivers provided 63% of Barcelona’s drinking water, wells 34% and desalination only 3%. Two years later, desalination accounts for 33% of Barcelona’s drinking water, while wells provide 23% and its dwindling rivers just 19%, according to Barcelona’s municipal water company.

With reservoirs fed by river basins in northern Catalonia at just 25% capacity, limits have been placed on the amount of water available for agriculture, industry and some municipal uses. But the authorities did not have to take drastic measures like during the drought of 2006-2008 when tankers transported drinking water.

“We knew sooner or later a drought would come,” plant manager Carlos Miguel told The Associated Press during a recent visit to the Llobregat plant.

“As long as the drought persists, the plant will continue to operate. It’s clear.

Although the construction of the Llobregat plant is the result of authorities heeding warnings from climate experts and planning ahead, it has high economic and environmental costs.

In the desalination process at the Llobregat plant, for every 0.45 liters of fresh water, approximately 0.55 liters of extremely salty brine is produced as waste. The process of reverse osmosis, where high pressure forces seawater through membranes that separate the salt, also requires a lot of energy that is not yet entirely from renewable energy sources.

The Mediterranean region is warming at a faster rate than many other parts of the globe, leading to a record year 2022 in Spain and widespread drought that is hurting agriculture. The lack of water is particularly acute in the northeast of Catalonia, whose water agency predicts that its water resources will decrease by 18% by 2050.

Water authorities expect the Barcelona region to be heading into an official “drought emergency”, which will involve tighter restrictions, by September.

“We expect the rest of May to have above-average rainfall, but that doesn’t make up for 32 months of drought,” Samuel Reyes, director of the Catalan Water Agency, said recently.

Desalination has been a key element of Spanish water policy for over half a century. The island of Lanzarote, in the Spanish archipelago of the Canary Islands, installed Europe’s first desalination plant in 1964, and the industry has grown steadily in this summer-prone southern European country. long and dry. The development and diffusion of the reverse osmosis technique in the 80s and 90s, together with the reduction in costs, led to its establishment in many areas of mainland Spain.

Spain is now fourth in the world for its desalination capacity, about 5% of the global total, behind Saudi Arabia, the United States and the United Arab Emirates, according to the Spanish Association of Desalination and Reuse of Water. water. Desalination capacity has steadily increased around the world over the past decade, with the technology seeing a greater increase in Europe and Africa.

Spain has some 800 desalination plants capable of producing 5 million cubic liters of water per day for consumption, agriculture and industry. If this were dedicated solely for human consumption, it would quench the thirst of 34 million people, or more than 70% of the Spanish population.

As part of a 2.2 billion euro ($2.4 billion) drought relief program, Spain’s national government said this week it was setting aside 220 million euros ($238 million) to expand another desalination plant north of Barcelona, ​​plus an additional 200 million euros ($216 million) for a plant on the southern coast of Spain. It has also pledged to spend 224 million euros ($242 million) to improve water purification systems in southern Spain.

This small miracle of scientific innovation, however, carries even more costs.

According to the public company that manages the Llobregat plant, a thousand liters of desalinated water cost 0.70 euros to produce, compared to 0.20 euros for the same quantity of water drawn from the Llobregat river and purified for consumption. This means a heavier tax burden and possibly higher water bills.

Xavier Sánchez-Vila, professor of civil engineering and groundwater expert at the Universitat Politecnica de Catalunya, said that while desalination plants like the one in Barcelona have provided a lifeline in times of crisis, authorities should continue to diversify their strategies and focus on improving water purification and reuse.

“Of course with climate change we know droughts are going to be more frequent and so there is this need (for desalination),” he said. “But in economic terms, I’m not quite sure it makes sense to keep building a bit more maybe, but knowing that it’s a very expensive solution.

Instead, Sánchez-Vila applauds Barcelona’s increased use of treated wastewater at a separate treatment plant located next to the Llobregat desalination plant. This treated water, which is reintroduced upstream and then available for reintroduction into the city’s supply, now represents 25% of Barcelona’s water.

The most pressing issue facing the planet is the energy-intensive processes involved in desalination.

Spain produced 42% of its electricity from renewable energy sources in 2022 and it hopes to reach 50% this year, but it still uses large amounts of natural gas which heats the planet. The electricity generated by the solar panels at the Llobregat power station is intended for the electricity grid, and not directly for site operations.

Julio Barea, water expert for Greenpeace in Spain, insists that desalination is not a panacea.

Barea cited the steady increase in water use in Spain over the past decades to support two of the country’s economic pillars: agriculture and tourism. Around 80% of Spain’s water is used for agriculture, Greenpeace calculates, while coastal areas including Barcelona are huge tourist magnets, many of which feature hotels with swimming pools that need to be filled. Water restrictions soon to be implemented in Catalonia will prohibit the filling of private pools, while hotels will still be able to fill their own.

And then there’s the impact of dumping waste brine into the sea, where its super salty load can harm the ecosystem.

“(Authorities) have to provide clean water to people, but desalination plants have an impact because they are basically water plants that need a lot of energy,” Barea said. “It should be a last resource, and we should ask ourselves how we got into this situation.”


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