Floating sea farms: A solution to feed the world and ensure freshwater by 2050

The sun and the sea – both abundant and free – are being harnessed in a unique project to create vertical sea farms floating on the ocean that can produce fresh water for drinking and agriculture.

In what is believed to be a world first, University of South Australia researchers have designed a self-sustaining solar-driven system that evaporates seawater and recycles it into freshwater, growing crops without any human involvement.

It could help address looming global shortages of freshwater and food in the decades ahead, with the world's population expected to reach 10 billion by 2050.

Professor Haolan Xu and Dr. Gary Owens from UniSA's Future Industries Institute have developed the vertical floating sea farm which is made up of two chambers: an upper layer similar to a glasshouse and a lower water harvest chamber. "The system works much like a wicking bed that household gardeners might be familiar with," Dr. Owen says.

"However, in this case, clean water is supplied by an array of solar evaporators that soak up the seawater, trap the salts in the evaporator body and, under the sun's rays, release clean water vapor into the air which is then condensed on water belts and transferred to the upper plant growth chamber."

In a field test, the researchers grew three common vegetable crops – broccoli, lettuce, and bok choi – on seawater surfaces without maintenance or additional clean water irrigation.

Image source: University of South Australia.