Giant greenhouse grows tomatoes using solar-powered desalination

A commercial greenhouse that grows tomatoes using desalinated water produced by solar-thermal technology will save 700 million litres of freshwater and 14,000 tonnes of CO2 equivalent a year.

Sundrop Farms, which supplies fresh fruit and vegetables to businesses across Australia, has secured £76m worth of private funding for the 20-hectare (0.2km2) greenhouse in Port Augusta, South Australia.

Set for completion in 2016, the greenhouse will use desalinated seawater to grow crops. And the on-site desalination plant will be powered by concentrated solar-thermal technology (not solar PV panels).

“As the world’s population continues to grow, Sundrop Farms is de-coupling food production from finite resources and relying instead on renewable resources to grow the world’s food industry, not just profitably, but sustainably,” Sundrop said in a statement. 

How it works…

The solar-thermal desalination process – which Sundrop Farms says is scalable – will see heliostats (computer-controlled mirrors) focus sunlight onto a tower where the energy is used to convert water to steam. The steam is then used to desalinate seawater; to generate electricity and to provide greenhouse heating.

A spokesperson for Sundrop told edie that there were no plans to market this new desalination system by itself, but the company has targeted some potential new agricultural sites. “Sundrop’s business operates at its optimum efficiency and profitability when located in arid regions with lots of sunshine, close to the sea or a saline water resources and in proximity to consumer end-markets,” the spokesperson said.

“Many countries of the Middle East possess these characteristics and it is therefore the next region of priority.”

Water scarcity

Sundrop Farms has become known as a leader in sustainable horticulture for the arid world. The firm, which stocks Coles Supermarkets – one of Australia’s largest retailers – claims to have created a proprietary food production system which grows produce year-round in greenhouses that use the abundant and renewable resources of sunlight and seawater.

It will use Frazer-Nash Consultancy to provide engineering and tehnical support for this latest project.

A recent UN report warned that the agricultural sector – which uses 70% of the world’s water supplies – must take steps to reduce its vast consumption, as 2.9bn people could face water shortages by 2025. The most acute stresses will be felt in warmer, low-resource areas like the Middle East; the very areas which could suit Sundrop’s technology the most.

Check out edie’s own analysis of four other ways we could sustainanably feed a mushrooming population.


 Brad Allen

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