After the size and the location of the productive zone of the geothermal reservoir are identified by a profound reservoir exploration, the system is developed by drilling at least two wells into the production horizon. Hot water or steam is extracted from the production well (red) via the well head into the power plant. Depending from the type of the resource (whether it is steam or hydrothermal controlled) energy from the hot source is transferred to either a turbine (direct use) or a secondary expansion fluid (binary cycle) to drive the turbine. After turbine excess energy can be extracted in an additional heat exchanging process. Now, the cooled geothermal fluid returns by the injection well (blue) into the reservoir, where it will be reheated in times. There must be an adequate distance from the production to the injection well to avoid a hydraulic bypass.