Cogeneration applied to very high efficiency thermal seawater desalination plants

aweelah A2 is the first independent water and power project in Abu Dhabi under the government privatization policy. In esponse to the Abu Dhabi Water and Electricity Authority (ADWEA) request for proposals, CMS Energy prepared and ubmitted their offer in April 1998. Following clarifications, the Power and Water Purchase Agreement was signed on 3 ctober 1998. CMS appointed Mott MacDonald as their technical advisers for the tender and project phases. The Taweelah 2 plant will comprise a 720 MW combined cycle power plant and 50 migd MSF desalination plant. Three Siemens type 94.3a gas turbine generators with exhaust heat recovery boilers will supply steam to two back pressure steam turbine enerators. Exhaust steam will be taken to four Hanjung 12.5 migd single deck cross tube MSF distillers, equal in capacity to he largest units ever built. Carbon dioxide gas recovered from the distiller air ejectors will be used for remineralizing the istillate. Seawater will be drawn from an existing intake channel serving the complete complex. The boilers are designed for a igh level of supplementary firing to meet the wide variations in electrical load on the Abu Dhabi grid, with full water output. onstruction of the US $750 million project, located between the existing Taweelah A1 and B stations, began in April 1999. irst power production is scheduled in May 2000, first water production in May 2001 and completion in August 2001. The lant will be owned and operated by Emirates CMS Power, jointly owned by CMS and ADWEA. This paper describes the esalination and power plant and outlines the power and water purchase aspects of the project. The high thermal efficiency of he combined cycle and MSF plant minimizes fuel consumption, heat rejection and atmospheric emissions, making this one of he best plants in the region from an environmental standpoint.