This Greenhouse Could Grow Food in the Desert With Just Seawater, Sunlight

A first-of-its-kind solar-powered greenhouse has turned a barren desert into a fertile land.

Sundrop Farms in the Port Augusta region of Adelaide, South Australia offers a unique kind of solar farming, using no soil and no groundwater, or even pesticides and fossil fuels. The company has spent six years developing the idea, creating its first plant in Port Augusta in 2010. It eventually grew into a 20-hectare solar-powered plant that could produce 15,000 tons of truss tomatoes every year with just sunlight and saltwater.

"You need to think about what you have and not so much what you don't have," Reinier Wolterbeek, a civil engineer who co-founded the project, told the Australian Broadcasting Corp (ABC). "Not a lot of people thought you could grow vegies in the desert, but I think you can. If you think smart about it there is a solution."

Water for the crops is sourced from the nearby Spencer Gulf, which is then converted into fresh water using a thermal desalination unit. The system creates enough fresh water that could irrigate about 180,000 tomato plants in the greenhouse.

The greenhouse is built with 23,000 mirrors that reflect sunlight towards an 115-meter high receiver tower, generating solar power for the crops. On sunny days, it could produce 39 megawatts of thermal energy, which would be used for the desalination system, as well as for electricity and heating.

In the summer, temperatures could rise up to 48 degrees Celsius (118 degrees Fahrenheit), which makes the arid Port Augusta region not suitable for conventional farming. But in the greenhouse, the vegetables are grown in coconut husks that are bordered with seawater-soaked cardboard, which could keep the crops cool and healthy. During the winter, the solar heating could keep the greenhouse warm. Pesticides are no longer needed since the seawater already cleans and sterilizes the air.

Sundrop Farms plans to open more of these types of greenhouses in the United States and Portugal, and another one in Australia.