Opinion: Could more commercial crops be irrigated with desalinated water?
By Chilean Union Association of Irrigation and Drainage (Agryd) president Luis Gurovich
Humanity is facing a milestone unparalleled in the history of civilization: for the first time human ingenuity has managed to make seawater available as a source for irrigating agricultural crops and the production of food.
Technological developments over the last five years mean desalinated seawater can be obtained at a compatible cost for the profitability of some specialty crops.
This accelerating trend in the reduction of desalinization costs, thanks to the discovery of new membranes coming from carbon and silicon in thick nanometric layers, such as graphene, promises to cut the current cost of desalinization - which today is US$0.43 per cubic meter - by 100 times.
Of this cost, just US$0.22 corresponds to the electricity required for the inverse osmosis process and the rest is distributed amongst costs for replacing filter membranes, operational costs and the amortization of capital invested in the desalinization plant. Five years ago, the cost was US$0.78 per cubic meter.
This means cultivation could take place on large extensions of completely desert-like soils, which today are unproductive due to a lack of water. This would lead to the production of food that a growing global population requires.
The use of desalinated seawater is economically profitable today when the process is done in large-scale plants that are capable of producing 400,000 cubic meters per day, under three additional conditions:
- That you use energy produced during times of the day with less electricity consumption.
- That the desalinated water is used firstly for the urban population, to later be purified adequately with the aim of meeting standards for irrigation water quality.
- That the efficiency of irrigation water use in agricultural crops is practically 100%, like what is achieved today by modern high-tech, high-precision localized irrigation systems.
The double use of water (first urban and then agricultural) makes the cost of production profitable for this new source of water resources.
Some countries are seriously lacking fresh water and are already using desalinated seawater for crop production, amongst them Israel, Spain, Qatar, India, Egypt, Australia, the United States and the United Arab Emirates.
Obviously, in some of these countries, the cost of producing and distributing desalinated water receives some kind of temporary government support; that's why a large amount of frontier research resources are invested to discover and scientifically evaluate new filtering materials, new photovoltaic systems for solar power and new developments in high-precision, pressurized and efficient irrigation.
The costs of fruit production have been increasing exponentially in recent years, and on a global scale. However, adding a cost of US$3,000 per hectare under a concept of high quality irrigation and with full security of supply is no longer a utopia for the fruit industry.
This vision could be developed in areas that today are unproductive, bringing together optimal agronomic and environmental qualities for the development and production of fruit orchards with species and varieties that are highly profitable.
Related story: Seawater greenhouses turning the tide of desertification