Large scale industrial use of ozone is based on the dielectric barrier discharge principle. Intense research work over recent years has contributed to an understanding of the barrier discharge and has directly influenced the performance of today's ozone generators. At present, the trend is to reach higher and higher ozone concentrations. Apart from the economical benefit of diminishing the oxygen consumption, recent developments of process design in water and wastewater treatment show clearly the advantages of using high ozone concentrations. TRAILIGAZ has intensified its research efforts in order to cope with these new and more stringent requirements. The parameters limiting the obtainable ozone concentration have been and steadily reviewed under the aspect of simultaneously increasing the energy efficiency and thus reducing the electrical power consumption. This report includes a survey of the developments and important improvements in technology by ozone generation from the 60's to the 90's. The state-of-the-art in today's (and tomorrow's) ozone generation technology is presented. Special importance is placed on the use of oxygen. The result of the efforts, a new high-technology, high efficiency ozonizer, with its advanced features is presented. It permits the use of high ozone concentrations to become far more attractive and it will surely stimulate further developments in process technology. This work has also led to improvements in air fed generators and comparisons with conventional technology are presented.