Analysis of drilling cuttings during
drilling work.

Copyright: GFZ Potsdam/Erbas

Modern exploration methods facilitate more effective search for sources of geothermal energy.

Worldwide, geothermal energy continues to grow as a source of electric power. The world leader in geothermal energy is Iceland. In the past years the northern European island doubled geothermal electric power supply alone to more than 500 MW annually. Not only in Iceland but also in central Europe, dynamic development has become evident. In Germany more than 100 MW of heat is produced from geothermal sources. At the closing conference of the EU project I-GET (Integrated Geophysical Exploration Technologies for deep fractured geothermal systems) in Potsdam, Germany, new methods were introduced for better exploration of such geothermal sources.

“The goal is to find geophysical methods for exploring potential geothermal sites that can then be developed in a targeted way. This can reduce the risk of expensive erroneous drillings,” suggests Ernst Huenges, head of Geothermal Research at GeoForschungsZentrum (GFZ). Alone in the region Travale in Italy, a European team of scientists localized geothermal sources with a potential of 1000 wind power plants. “The new methods are important decision supports for selecting the location of future geothermal projects,” the researcher emphasizes. The researchers explore specifically in regions that contain large amounts of hot water. “Large amounts of water require a different exploration approach than energetically comparable quantities of oil or gas,” states Huenges.

A rough resource map has already been prepared for all of Europe. “However, if we go into detail, there are many gaps,” stresses the scientist. This means new exploration methods for nearly every project. The new approaches were tested at four European geothermal sites with different geological and thermodynamic conditions: high-temperature storage sites were studied in Travale, Italy, (metamorphous stone) and in Hengill, Iceland, (volcanic stone); two storage sites with medium temperature in deep sedimentary stones are Groß-Schönebeck, Germany, and Skierniewice, Poland. “The method is based on the measurement of seismic speed and electrical conductivity underground, which enables conclusions concerning the stone’s physical characteristics in the depth,” explains the researcher.

For each project, a precise local 3D seismic exploration needs to be conducted to enable imaging of the substrata. “Given very careful preparations, a drilling should produce large amounts of hot water,” ventures Huenges. The range of application domains for geothermal energy is vast. Electricity can be generated from hot water, heating can be provided for regional heating systems, and even an industrial site that requires refrigeration can be connected.

“Reliable geothermal technologies are in demand worldwide. Even geothermally explored nations such as Indonesia and New Zealand are interested in the I-GET results,” says Huenges. GFZ is continuing its research and development in geothermal energy and is currently building an international center for geothermal research that will conduct large application-oriented projects at national and international levels.

Source: Pressetext.at