The continuous fluid production essential for an economic energy provision can strongly be affected by corrosion. In order to realise both, reliable geothermal plant design and its operation, all potentially occurring corrosion processes must be understood comprehensively. For this purpose various investigations on material and fluid characterization are carried out. Previous projects already investigated preventive, active and passive methods of corrosion protection for common, high-strength C-steels, nickel base and titanium base alloys under the specific constraints of geothermal plants. Ongoing research is now transferring the results of these previous works from laboratory scale to in-situ scale and to industrial application, respectively. The geothermal site at Groß Schönebeck can be used by the GFZ for in-situ research experiments. Additional laboratory experiments allow investigating the effect of fluid composition on corrosion of different materials.