In cogeneration power/water production using the multi-stage flash (MSF) desalination process, the MSF is energy intensive . The value and the cost of the thermal energy supplied to the MSF process depends on the method of supplying this energy. Steam can be supplied directly from fuel operated auxiliary boilers (FOABs) or from waste heat recovery boilers (WHRBs) associated with gas turbine power generation. In the case study plant, both FOABs and WHRBs are used. The use of FOABs to produce relatively low-pressure and temperature steam to drive the MSF process is, thermodynamically, wasteful. The thermal energy supplied to operate an MSF unit is in the form of relatively low-pressure steam to the brine heater (heat input section). The saturation temperature of this steam should be only few degrees above the top brine temperature (TBT). The TBT temperature depends on the method applied for treatment of seawater [14, 15].