Seawater Greenhouse technology for sustainable intensification of agriculture in world’s arid regions

The Seawater Greenhouse is an innovative technology to address problems at the food-water-energy nexus. It is a growing system powered by renewable energy and cooled by seawater, allowing sustainable intensification of agriculture to meet the soaring demands for food in the world’s arid regions. This presentation explains how the technology can be adapted to meet different climatic conditions and economic constraints. To illustrate the different modes of operation, case studies are presented for designs already implemented in Spain, the United Arab Emirates, Australia and Oman. Further designs are in progress for Iran and Somaliland. Seawater evaporation, the key feature of the Seawater Greenhouse, is highlighted from the points of views of both space cooling and brine disposal. Space cooling enables extended growing seasons, diversification of crops and reduced evapotranspiration rates in hot climates – without expenditure of freshwater. Brine disposal comes into play when, instead of using raw seawater for cooling, the seawater is taken from the reject stream of desalination plants. This introduces the possibility for improved brine management, which can also be applied for inland desalination scenarios where brine disposal is especially problematic. The seawater greenhouse can be used for volume reduction of brine, to prevent deterioration of soil associated with unmanaged discharge of brine to the environment. The presentation also shows how the design of the Seawater Greenhouse has been optimised through fluid dynamic modelling to achieve targets for cooling and brine disposal in certain case studies, in particular that of Somaliland where a pilot is currently being developed to meet exacting requirements with regard to low cost and robust construction.