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DESALINATION

By Edouard Perard

Agriculture consumes the most fresh of Arab Emirates, and the United States. The most any other sector. Globally, agriculture is respon- active private firms in the market sible for an average of 70 percent of include Doosan, General Electric, Hyflux, Suez, consumption; in some countries, that figure and Veolia Environment. jumps to 80 to 90 percent. Given the forecasted During the last several years, important techno- global increase, the agriculture sector logical improvements have significantly lowered will have to produce 70 percent more by requirements—the primary operating 2050, according to estimates from the Bonn cost. In the early , desalination con- 2011 Conference: The Water, Energy and Food sumed more than 20 kilowatt hours of electricity Security Nexus. This will stress water per cubic meter. Currently, desalination plants even further. Governments worldwide, facing a consume between 3.0 and 4.5 kilowatt hours of possible water crisis in arid regions, are search- electricity. At this rate, the cost of desalinating ing for options to ensure a reliable water per cubic meter ranges between $0.75 and for agriculture, and desalination is one of those $1.25 for , according to the Interna- options. tional Desalination Association. Desalination for is a well-estab- Wider use of salt water for would lished technology. The International Desalina- free freshwater for other uses and increase food tion Association counts more than 10,000 security for people living in dry coastal areas. desalination plants around the world, 99 percent As Wired reported in 2010, a British company of which are small scale projects. Many of these has developed a low-cost irrigation system that projects are implemented under public-private allows saline and , which contains partnerships (PPPs), but most are established more than freshwater, to be used for as engineering, procurement and construction growing crops. The Dutyion Root Hydration projects. Most plants are located in Algeria, System uses a network of underground pipes to China, , , Spain, United deliver water directly to a ’s roots. Water

36 | IFC.ORG/HANDSHAKE IRRIGATION for AGRICULTURE

then diffuses through the walls of the polymer While the experience with desalination for pipe because of differences in moisture levels, agriculture has so far been limited to some which act as filters and leave contaminates projects in , Spain, and high-income behind. Almost any water source can be used— Middle Eastern countries, several projects even industrial wastewater—without the need are currently under consideration in low- and for secondary purification. middle-income countries. In Morocco, for As always, environmental costs also need to be example, the government is planning a PPP to taken into consideration, especially air pollu- build a new desalination plant in the Chtouka tion and gas emissions for large region to provide water for high-value crops. desalination plants. There may also be damage (IFC is the project advisor.) In Chile, a private to marine due to the pumping of seawater firm has proposed to develop a 2,000 ha unoc- into the plant and discharge of residual salts and cupied government-owned agricultural , . combined with a desalination plant, under a PPP in Llanos de Caldera. The land would be rented At its current price level, desalinated water is still to farmers, who would then pay for desalinated not economically viable for most agricultural water to be used in irrigation. use, considering the tremendous amount of water necessary for food production (1,300 and Though desalination for agriculture is still at an 3,400 liters of water required for one kg of wheat early development stage, technological improve- and rice, respectively). However, desalinated ments leading to lower-cost solutions may make water has become more affordable for high value it a more viable option to ensure a reliable water crops such as fruit and citrus products, which supply for agriculture. For the foreseeable future, are less water-intensive (13 and 50 liters of however, desalination will remain limited to water required for one tomato and one orange, high-value crops. respectively). Photo © Lisa F. Young/istockphoto

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