A person looks out at the view of the pipeline that transports seawater to filters at Europe’s largest desalination plant for drinking water located in Barcelona, Spain on May 16, 2023. Europe’s largest desalination plant for drinking water had largely remained idle since its construction near Barcelona over a decade ago. But since a prolonged drought gripped Spain, the plant has been running at full throttle.
In April 2021, before the drought, rivers provided 63 percent of Barcelona’s drinking water, wells provided 34 percent and desalination just 3 percent. Two years later desalination makes up 33 percent of Barcelona’s drinking water, while wells provide 23 percent and its shrinking rivers just 19 percent, according to Barcelona’s municipal water company.
In the desalination process at the Llobregat plant, for every 0.45 liters of fresh water, around 0.55 liters of extremely salty brine is produced as waste. The reverse osmosis process, where high pressure forces seawater through membranes which separates the salt, also requires a lot of energy that doesn’t yet come entirely from renewable energy sources.
“We forecast that for the rest of May rainfall will be above average, but that does not make up for 32 months of drought,” Samuel Reyes, head of the Catalan Water Agency, said recently. Spain has some 800 desalination plants that can produce 5 million cubic liters a day of water for drinking, agriculture, and industry. If that were dedicated solely for human consumption, it would quench the thirst of 34 million people—over 70 percent of Spain’s population.
“Of course, with climate change we know that droughts are going to be more frequent and therefore there is this need ,” he said. “But in economic terms, I am not completely sure whether it makes sense to keep building them. A few more maybe, but knowing that these are a really expensive solution.”