Prof D Chandrasekharam

Saudi Arabia’s percapita consumption of fresh water (domestic and agricultural sectors)is about 960 m3/y. Since the country receives scanty rainfall, the aquifers are notadequately recharged and the water demand is supported by fresh water generatedthrough desalination process. Saudi Arabia uses energy intensive conventional desalinationprocess while the world uses reverse osmosis process. The conventional desalinationmethods consume 12 x 109 kWh to generate 1 m3of fresh water.Thus this process emits large amount of CO2. The cost to generate 20,000 m3/day offresh water through vacuum membrane technique, is about US$ 0.53/m3 while the cost togenerate similar volume of through using conventional energy source is US$ 1.22/m3. The CO2 related temperature effect that is currently experiencedin Saudi Arabia has direct impact on the agriculturalproduction, especially with respect to wheat production. If the CO2 emission trendcontinues at the current rate, then the wheat production will drastically be reduced. In addition to the climate, water stress condition that forcedthe government to change the wheat production policy will increase food security threatto the country. In addition, trace element concentrations in agricultural soils irrigatedwith treated sewage water has increased considerably relative the concentration of suchelements in soils irrigated with normal groundwater and desalinated water. This built upof trace elements concentration in soils in certain parts of the country is deteriorating thesoil fertility and thereby reducing the crop production. Thus for domestic and agricultural sectors need, desalinated water can be used and subsidy on the cost of desalinated water can be removed once the desalination process lines using geothermal energy source stabilizes. The current cost of desalinated water, processedthrough conventional energy source, in Saudi Arabia with subsidy is 0.03 US$/m3 whichis far less than the average cost of US$ 6/m3. This cost is much higher compared to thecost projected using geothermal energy source. Once fresh water is available at affordable cost ( with same cost without subsidy) and with abundantfossil fuel reserves, the Saudi Arabia can have strong control over energy and foodsecurity and help other gulf countries and countries surrounding the Red Sea to improvetheir fresh water demand.