Natural draught cooling towers are inevitable for the economic generation of electricity under environmental aspects: In any thermal power plant heated stearn drives a turbogenerator, which produces the electric energy. In order to create an effective heat sink behind the turbine, the stearn is condensed and recyc­ led into the boiler. This requires a large amount of cooling water which is heated by running through the condensor. Even in the most efficient fossil fuel thermal (nuclear) power plants, only about 40 (30)% of the generated heat is turned in­ to electric energy. The rest of heat of 60 (70)% is discharged into the environment through the smokestack and the cooling wa­ ter circuit. To avoid thermal pollution of natural water resources the heated cooling water should be recooled artificially in a cooling sys­ tem and reused. Among all technical solutions natural draught cooling towers are effective, economic and widely spread cor­ rective measures. In large power plants only natural draught cooling towers are able to recover the immense quantities of water required for cooling. Thus only these engineering struc­ tures are able to balance environmental factors, economic in­ vestment and operating costs of the power station with the de­ mands of a reliable electric energy supply.