Geothermal energy: Renewable energy from terrestrial heat
Some of the geothermal heat energy rises to the earth's surface from the earth's core at temperatures of up to 7,000 degrees Celsius. However, the energy flow generated by the constant decay of natural radioactive elements in the earth's mantle and crust is far greater.
Geothermal power plants harness this thermal energy for human use by pumping hot thermal water to the earth's surface, sometimes from depths of several thousand metres ("deep geothermal energy"). In the above-ground part of the plant, the water runs through a heat exchanger. The energy transferred is used to generate electricity or to supply district heating. The thermal water is then channelled back underground. At lower temperatures, electricity generation becomes uneconomical and the energy is "only" utilised as heat.
Tasks of GRS
GRS carries out research into the safety and availability of geothermal plants. GRS researchers utilise their knowledge and experience from fields such as plant safety or radiation and environmental protection. In particular, the experience gained from repository safety research relating to physical and chemical processes and interactions in the deep underground (e.g. saline solutions, high temperatures, material behaviour) is highly relevant in connection with geothermal projects.
To date, we have carried out the following work:
- Using an interdisciplinary systems analysis, our researchers in the Geo-Sys project have investigated various plant conditions and their potential impact on protected goods - for example, humans, animals, plants and water.
- In the Geo-Dat project, a thermodynamic database was created that can be used to calculate complex geochemical processes in deep geothermal layers.
- In the ANEMONA project, GRS experts have researched how the monitoring of geothermal plants can be optimised and have also developed specific technical methods for this.
- Naturally occurring radionuclides can accumulate or be deposited in special technical processes such as geothermal energy (NORM/ TNORM). GRS develops radioecological models that can be used to calculate the distribution of these radionuclides. We assess the landfilling and utilisation of NORM residues, clarify transport issues, and help to determine the radiation exposure at workplaces with increased natural radioactivity.