Az-Zour North Independent Water and Power Project, Kuwait
Phase one of the Az-Zour North Independent Water and Power Project (IWPP) is located at Az-Zour, approximately 100km south of Kuwait City. The desalination plant comprises a multiple-effect distillation (MED) unit capable of producing 107 million imperial gallons per day (MIGD) (405,000m³/d) of drinking water, which is equivalent to 20% of Kuwait's installed water treatment capacity.
Construction of a desalination plant and a gas-fired 1,500MW combined-cycle power plant was completed in November 2016.
The treated water and the power produced from the complex are supplied to the country's national power and water grid operator Kuwait Ministry of Electricity and Water (MEW) under a 40-year long-term Energy Conversion and Water Purchase Agreement (ECWPA).
Main contractors and project background
The Northern Water Plant (NWP) is an A$94m (approximately $100m) water recycling facility constructed in northern Geelong, Victoria, Australia.
The desalination and power project forms part of the overall IWPP being developed by ENGIE (previously known as GDF Suez) (17.5%), Sumitomo (17.5%), Abdullah Hamad Al-Sager and Brothers (5%), and Kuwaiti Government entities (60%). The overall project aims at generating 4,800MW of electricity and approximately 280MIGD of desalinated water, and is being carried out in five phases.
The engineering, procurement and construction (EPC) contractor for the desalination plant is Veolia subsidiary Sidem, while Hyundai Heavy Industries (HHI) is the EPC contractor for the power plant. The contractors were awarded $1.4bn worth of contracts for the first phase of the IWPP in December 2013. The investment for the desalination plant is estimated at €320m ($434m approximately).
ENGIE and Sumitomo undertake operations and maintenance works at the plant on a 50:50 basis.
Construction of Az-Zour North desalination plant
The MED process implemented for the treatment of seawater at Az-Zour North is popular for its ability to adapt to fluctuations in water demand.
The feed water for the desalination plant is sourced from the Persian Gulf and is conveyed for distribution via a new intake system constructed for desalination and cooling purposes. A connecting structure to the existing discharge system will be built simultaneously.
Both the intake and discharge systems are shared facilities for all the phases developed at the Az-Zour North site. The power required for running the facility is supplied from the Az-Zour North power plant.
The distillate water is re-carbonated before it is delivered to a water distribution complex (WDC) reservoir through four new pipelines to be constructed by MEW. A new 400kV substation was constructed by the developer to discharge the generated power.
Multiple-effect distillation technology
The MED technology involves multiple stages where feed water is heated by steam in tubes. Each subsequent stage is maintained at a lower temperature. The steam condenses into distillate (fresh water) inside the tubes and flows into the tubes of the next stage, heating and evaporating more water.
Seawater is continuously fed on the top of horizontal tubes, in each stage decreasing the pressure to consecutively lower the temperature required to bring the water to boil. The water drips from tube to tube until it is collected in the final stage.
The MED process operates at a low temperature (between 60°C and 70°C) using the thermal output of the power plant to heat and evaporate the seawater to avoid corrosion.
In the last stage, the produced steam condenses on a distillate condenser, which is cooled by seawater. A portion of the seawater from the outlet of this condenser is further used to repeat the process, while the remaining water is discharged into the sea.
Brine and distillate are collected in individual stages, until the last stage where they are separated by centrifugal pumps.
The technology consumes three times less power than other thermal processes and also requires minimal pre-treatment compared to reverse osmosis.
Contractors and financiers
Nippon Steel & Sumikin Stainless was awarded a contract from MEW to supply 4,300t of ASTM S32304 and S31803 grade duplex stainless-steel plates for the integrated power and desalination plant. Technical advisory services for the project were provided by Lahmeyer International.
The total cost of the IWPP, including the cost of construction, is estimated to be approximately $1.8bn. Japan Bank for International Cooperation (JBIC) co-financed $1.43bn of the project cost along with other international commercial banks. Other lenders include National Bank of Kuwait (NBK), Nippon Export and Investment Insurance, Bank of Tokyo-Mitsubishi, Sumitomo Mitsui Banking Corporation and Standard Chartered Bank.
The remaining amount was invested by the Kuwaiti Government (60%), Sumitomo (17.5%) and ENGIE (17.5%).