The future of farming on ocean waves
University of South Australia researchers’ floating vertical sea farms harness the sun and sea to power self-sustainable greenhouses and combat growing global shortages of freshwater and suitable farmland.
Farmers tending an armada of greenhouses, floating along the coastline, with solar-powered desalination providing freshwater for self-irrigation. This futuristic vision is often connected with sci-fi movies and books.
As freshwater and suitable agricultural land diminish in quantity and quality, our planet becomes less capable of sustaining the world’s growing population.
Pioneering AgTech researchers Prof Haolan Xu and Dr Gary Owens from the University of South Australia are turning science fiction into real-world solutions for global water shortages and the growing scarcity of arable land.
By 2050, approximately 2.4 billion people are likely to experience water shortages (United Nations) as the global supply of water for agricultural irrigation is expected to decline by around 19%. While Australia is ranked 6th in the world for the most arable land, extreme weather, land and soil degradation, spreading of toxic substances and urbanisation are driving a decline in high-quality, arable land suitable for farming.
Prof Xu and Dr Owens’ research harnesses the power of sun and sea in their vertical sea farm system. The farm consists of 2 chambers: an upper greenhouse and lower evaporator-based water harvest chamber.
Solar evaporators in the bottom chamber soak up the seawater, trap the salts and release clean water vapor into the air. This vapor then condenses on water belts and is transported to the soil in the upper greenhouse.
Their elegant design takes into consideration varying solar light angles, ensuring that the evaporator, even under a double structure, receives sufficient sunlight throughout the day for effective operation.
In successful field tests, 3 common vegetable crops – broccoli, lettuce and bok choi – were grown in their vertical sea farm system without maintenance or additional clean water irrigation.
While the design is only proof-of-concept at this stage, the vertical sea farm system has great potential for scalability due to its modular design. This scalability is crucial for adapting to various farming needs and environmental conditions, allowing farmers to start small with high-income crops and expand gradually, catering to their production desires.
With material characterisation support from ANFF-SA, the next stages of development will involve enlarging the prototype and creating larger modules that connect to form multi-unit systems, eventually leading to a network of floating domes across the water.
Combating the global decline of arable land due to salinity issues and contamination from industrial activities, the floating sea farm provides promise to utilise ocean spaces for farming. This innovative approach not only addresses the pressing challenges of water scarcity and diminishing agricultural land but also paints a vivid picture of a sustainable future, offering hope for a future where humanity can thrive despite the environmental challenges we face.
Published 15 October 2024 in ANFF’s 2024 Casebook ‘ANFF NEXT‘
Posted 04 March 2025
