The technical development of geothermal resources takes place in three project phases. The aim of the exploration phase is to map the geothermal conditions in the subsurface using geophysical methods and to define suitable drilling targets. In the drilling phase the suspected geothermal resource will be tapped, whereby the yield of the well can only be evaluated after the drilling phase. The production phase represents the final step and makes the geothermal heat usable either as district heating, electricity or cooling. Several years can pass from exploration to drilling to production.