The recommendations summarise the state of the art. Their aim is the proper exploitation of the ground for geothermal purposes without adversely affecting the ground or the groundwater on the one hand and the operation of the system and nearby buildings on the other. The recommendations should be used during consulting, design, installation and operation in order to achieve optimum and sustainable use of the ground at a specific location. Authorities responsible for supervising and approving projects can use the recommendations as a guide when taking decisions and making stipulations. The Geothermal Energy Study Group was set up in Bochum in 2004 and became the joint DGGV/DGGT study group in 2007. Some 20 specialists from universities, authorities and engineering consultants are active in the group and meet two or three times a year.