Freiburg (dpa/lsw) - Earthquakes in Basel or near Strasbourg triggered by drilling have damaged the reputation of the technology - but the State Office for Geology, Raw Materials and Mining is convinced that deep geothermal energy on the Upper Rhine can be safely extracted. "We are convinced that the resistance will disappear when the first geothermal plants are in operation and running smoothly on the Upper Rhine," said a spokeswoman for the regional council of Freiburg, where the state office is located.
The geothermal project in Vendenheim near Strasbourg, which has been stopped in the meantime, is not comparable to the projects on the German side. In Alsace, two years ago, drills were drilled directly into the bedrock, water was pressed in at high pressure and earthquakes were triggered. At the end of 2006, drilling into the bedrock triggered an earthquake with a magnitude of 3.4 in Basel.
The Freiburg authority points out that before approving drilling on the Baden side of the Rhine, the state office ensures as part of the approval process that restrictive drilling planning and execution prevent noticeable earthquakes. In order to obtain approval for drilling and testing, companies would have to produce a thorough investigation of the rock conditions and possible seismic activity. "The seismic activation of tectonic faults must be ruled out."
An example of functioning deep geothermal energy is the Riehen heating network. The Swiss community near Basel has been supplied with climate-friendly geothermal heat since 1994.
