Sundrop Farms have successfully piloted a solar greenhouse that uses solar thermal energy and saltwater to prove that a commercial scale greenhouse can be created to grow food in the desert. Using a parabolic trough array that will deliver around 36MW of thermal energy, the solar thermal energy is used to desalinate water for irrigation, and for heating and cooling.
Using the sun’s warmth to remove the salt from seawater to produce heating, cooling and power for growers to deliver fruit and vegetables. A 70 metre-long stretch of solar panels collects the energy and black tubing that runs through the centre of the panels is filled with thermal oil, which is heated up to 160 degrees Celsius. The oil is then pumped through the tube to a storage shed where the heat is used by a water storage system. A control mechanism then determines how that heat will be used, some for greenhouse temperature control, some to power the set-up, but most of the stored heat for desalination of tidal bore water. When the heat reaches the desalination unit and meets up with relatively-cold seawater, the temperature difference creates condensation, the end result being fresh water for use on crops. The brine ends up in ponds and the salt can be extracted as a saleable by-product.
A 20-hectare greenhouse facility will use seawater and energy to produce fresh water, salt and over 15,000 tonnes of tomatoes a year.
As a revolutionary way to solve problems in agriculture such as food and water scarcity, clean energy challenges and energy security issues; this concept has demonstrated sustainable horticulture practices and self-sufficiency. It has triggered projects in other arid regions, particularly in the north Africa and Middle East. The Sahara Forest Project will use the same unique technology to show the world what is possible with sun, seas and desert and a lot of ingenuity.