WATER-PRODUCING GREENHOUSES FOR SMALL TROPICAL ISLANDS: AHEAD OF THEIR TIME OR A TIMELY SOLUTION?

Water scarcity on small tropical islands limits water and food security for inhabitants. A Water-producing Greenhouse (WPG), using water-from-air (dehumidification) technology, can increase carrying capacity and life quality. In 2003, Canadian and Turks & Caicos Islands (TCI) researchers completed a Viability Study, supported by the Canadian International Development Agency (CIDA), for a WPG on Grand Turk (GT). Despite years of fund-raising efforts, this WPG remains to be built. Importing food and drinking water continues to be easy. Revisiting the study in today’s context is valuable given increasing transportation costs coupled with carbon emission reduction responsibilities. A 200,000 L/d WPG is feasible for GT’s humid tropical climate and saline, reverse-geothermal-gradient groundwater with 15°C coolant water drawn from 400–500 m depths. Establishing the business needs USD 5 million (2003; new estimates may be higher). Business opportunities include: sales of hydroponically-grown produce to wholesalers, retailers, restaurants, and value-added manufacturers of salsas and juices; sales of drinking water to the government, tanker-truck operators, breweries, and to bottling plants; export sales of premium brand 500 ml water bottles; sales of sport drinks; and sales of greenhouse tours and bottled water to cruise-ship tourists.