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For decades it’s been hoped that seawater could be desalinated at scale to produce fresh water, yet desalination plants still provide only around 1 per cent of the world’s drinking water. The reason for the slow progress has been cost. Desalination plants are expensive to build and use a lot of energy to run. Energy accounts for one third to more than half the cost of producing desalinated water.
In Saudi Arabia, the world’s largest producer of desalinated water, the process accounts for up a fifth of the nation’s energy consumption. But all this may be changing. A 2020 study found that globally, the average levelised cost of desalinated water could more than halve if solar power and battery storage systems were used.
Across the word, there are around 180 facilities currently under construction or in their design phase, mostly in the Middle East and North Africa. The two regions currently account for about half of all the world’s desalinated water production and are investing billions in the new infrastructure. Advances in solar power mean it’s getting cheaper to power energy-hungry desalination equipment in sunny and water-stressed areas.
Egypt and Morocco, for example, are building renewable powered plants designed both to provide drinking water and to irrigate crops. In south Australia, a self-cooling greenhouse design that uses wind to desalinate seawater for crops is part of a commercial project producing 15 per cent of Australian-grown tomatoes. Scientists are also making efficiency breakthroughs, such as new self-cleaning membrane technology which improves the desalination process.
One start-up, Core Power, is developing nuclear-powered offshore plants. Another, Oneka, is harnessing wave power for floating desalination units. This wave of growth and innovation is set to continue. A global desalination equipment market valued at $17bn in 2023 is expected to grow to $32bn by 2030, but despite these breakthroughs serious challenges remain.
Most facilities still use fossil fuels to power the plants, and the dumping of salt-saturated brine into the sea poses a risk to marine life. These problems will have to be addressed as a thirsty world looks to the desalination industry to provide its drinking water and irrigate its crops.
