This article is part of our special report Delivering water in the 21st century.
Faced with water shortages in its sunny south, Spain has become a European trendsetter in harnessing seawater for human use and is an industrial leader in desalination.
In other increasingly dry regions of southern Europe, desalination offers promise for farmers and households that compete for freshwater, say advocates who also see the technology as both economically vital to the European Union and an answer to its long-term water security.
“Without it, you’re lost,” said Miriam Balaban, secretary-general of the European Desalination Society in Rome. “There’s only one other source of water and that is the reuse of water [from manufacturing], but some people don’t want to drink that.”
The European Commission is due to issue its blueprint for safeguarding water supplies later this year, a document that is expected to examine the drought and scarcity risks and alternatives to tapping rivers and aquifers to meet competing demands.
Water providers in Spain – as well as Italy, Greece and Malta – are increasingly turning to desalination to address freshwater needs in dry periods and as rivers and reservoirs become more stressed due to climate change along with farm and household demand.
Cyprus gets more than 60% of its drinking water from desalination plants, government figures show, while rainy places like London and Amsterdam treat brackish water for municipal consumption.
Europe accounts for 10% of the world’s desalination capacity – the Middle East is the global leader, with 70% of capacity – and Spain’s production doubled in the last decade. Balaban’s group lists some 180 European companies involved in the manufacture and supply of plants and technology.
Spanish companies including Aqualia, Acciona and Bifesa along with multinationals like Dow Chemical, Siemens, Veolia and General Electric are among the global leaders in managing and building desalination operations.
A curse or a blessing?
With mounting concerns about water scarcity in parts of Europe, desalination may be one answer.
But desalination also raises environmental concerns – making seawater drinkable is an expensive and energy-intensive process depending on the salinity levels in the water.
Treating seawater requires thermal technology using heat and pressure to extract salt and costs some three times as much as treating water with a reverse-osmosis system that uses membranes to remove impurities.
Environmental groups including WWF and the European Environmental Bureau have for years raised concerns over the expansion of desalination plants and their potential harm to coastal habitats and generate far higher levels of greenhouse gas than conventional water plants.
A recent report by the European Environment Agency (EEA) adds weight to such concerns. The EU agency warns that the desalination process also produces chemical waste and brine – a byproduct that is heavier than seawater and can damage bottom-dwelling sea life when the discharged brine settles.
The energy needed to purify water is another concern, the report says, noting that plans to use desalination to address water challenges “could jeopardise the reductions in energy use planned under the EU's climate and energy package.”
Cleaner water – and air
The desalination industry says it is working to reduce its environmental impact. Manufacturers of the membranes used in purification are taking steps to cut energy consumption in the production process, and new technologies will make purification more efficient, said Santi Talo, the Barcelona-based sales director in Europe, Africa and the Middle East for Hydranautics, a membrane producer.
“Energy consumption is critical, and [desalination] companies are working to reduce energy and make production more efficient,” Talo said in a telephone interview.
Balaban, of the European Desalination Society, dismisses criticism about the environmental impact and says EU policymakers are doing little to promote a technology that could help address growing water scarcity. For example, the European Innovation Partnership on Water, announced on 14 May, does not list desalination amongst its proposals to address future needs.
Renewable energy could address concerns about carbon emissions, said Balaban, with renewables making water purification cheaper over the long term.
And she says that the cost of purifying water from the sea is reaching price parity because the price of treating river and groundwater will grow because of pollution and contamination.
“Conventional water is rapidly becoming more expensive and desalination is becoming less expensive,” Balaban said, “so it’s almost crossing over.”