Energy Efficiency Is a High Priority Among GCC Desalination Plants

Desalinated seawater is the primary source of water supply in the Gulf Cooperation Council (GCC), where freshwater is scarce, oil is plentiful and desalination using thermal distillation has been a reliable method of choice. Table 1 details current installed desalination capacities in the GCC countries, according to International Desalination Association (IDA) and Frost & Sullivan analysis. By 2025, another 15 million cubic meters per day (m³/d) will be added in desalination capacities in the GCC. Most of these additions will be seen in the Kingdom of Saudi Arabia (KSA), the UAE, Kuwait and Qatar.

Pumping Technologies

Desalination is a growing segment among the GCC countries as dwindling freshwater supplies and rapidly increasing population are leading to an unquenchable rise in freshwater demand. As the demand for freshwater grows, the size of desalination plants can be expected to increase, resulting in demand for pumps with higher pumping capacity. Distillation and reverse osmosis (RO) are the two major techniques used in the Middle East for desalination. Desalination pumps are required to operate in harsh conditions and handle abrasive and saline seawater. These pumps must withstand corrosion and optimize power consumption to reach efficiency goals. The choice of pumps depends on the desalination process and the application. Distillation pumps include seawater intake pumps, high-pressure pumps, recirculating pumps, brine pumps and potable water pumps. The pump types include radial pumps, volute pumps and vertical mixed flow pumps, among others. The distillation process generally requires large centrifugal pumps, which are characterized by low NPSH. RO pumps include seawater intake pumps, filtered water pumps, high-pressure pumps, booster pumps and potable water pumps. The pump types include both centrifugal and end suction pumps, multistage pumps and vertical mixed flow pumps, among others. Because the RO process requires water to be pumped at higher pressures, multistage pumps are required to generate the high head and discharge levels. Seawater intake pumps generally handle capacities more than 25,000 m³/hour, while process booster pumps may handle capacities in excess of 1,000 m³/hour. End users in the desalination segment are also looking at energy-efficient pumps. The energy consumption of a typical RO desalination plant is about 5 kilowatts per hour (kWh) per cubic meter. Energy-efficient pumps in desalination are a priority for end users looking to minimize the process's high energy consumption. Among the pump manufacturers who supply to desalination plants, major companies include Flowserve, Sulzer, KSB, Weir and Torishima. These companies have created a niche for themselves in catering to the specific requirements in the desalination sector in the Middle East.

Sustainable Developments

Energy is the single largest operational expense in production and supply of desalinated water. The cost of energy to produce a unit of desalinated water can be as high as 50 percent. According to the Centre for Strategic and International Studies, desalination accounts for between 10 to 25 percent of the energy consumption in the GCC. The KSA and the UAE spend US$3 billion on desalination every year. RO technology has gained much loyalty during the last decade among end users. The next step, according to many experts, is the incorporation of renewable energy into existing RO processes. The trend toward renewable energy will potentially reduce fossil fuel use and limit greenhouse gas emissions. Solar energy holds great potential in the desalination market. Challenges still remain, as the two solar technologies—solar photovoltaic and concentrated solar power—work best inland as opposed to on the coast. Overcoming technical and economic challenges of solar desalination will be the key to wider adoption and funding for research facilities. GCC countries have allocated approximately US$100 billion toward implementing sustainable water technology projects. As regional economies look to reduce dependence on fossil fuel and explore renewable energy sources, primarily solar, it is certain that desalination powered by renewable energy will be the way forward.