Geothermal power plants convert the thermal energy of the Earth into electricity. This is truly worthwhile in those areas where the upper layers of the Earth have a temperature of more than 100°C, such as Iceland or several parts of Italy. Hot steam at a temperature of over 150°C can be used directly to drive the turbines. Other processes that use the heat of the Earth at a depth of several kilometres are still in the trial stage. In these processes, water is pressed at a high pressure in hot rocky layers, where it heats up in artificially created cracks. From there, it is pumped again to the Earth’s surface by means of a second drill. This heat can be used directly for heating or for generating electricity.
