The present invention provides a configuration of a multi-stage flash desalination system including a thermal vapor compressor and a condensate flash tank, which allows to extract a vapor from the condensate before it is returned to the power plant and to compress this vapor and use it as part of the heating steam in the brine heater, which reduces the required amount of steam supply from the power plant, while the condensate returned to the power plant at a reduced temperature allows to utilize low grade heat of exhaust gases of a steam generator to re-heat the condensate, which results in a reduced energy consumption allocated to the multi-stage flash desalination plant and an improvement of the energy efficiency of the power plant.