The Potential of Deep Geothermal Energy in Tyrol—Based on a Pre-feasibility Study

Abstract

The economic use of deep geothermal energy is fundamentally controlled by the factors of rock permeability, temperature gradient, and depth. The carbonates of the Northern Limestone Alps are considered possible hydrothermal deep aquifers in Tyrol. This is the so-called main dolomite and Wetterstein limestone. For an initial assessment of the geothermal potential, information from the deep Kramsach Th1 borehole was used. With a temperature gradient of approx. 1.8 °C/100 m, which could be derived from the Kramsach Th1 borehole, temperatures of 65 °C at depths of approx. 3000 m and 100 °C at a depth of 5000 m occur in the Inn Valley expect. In addition, it is noted that further in the northwest of the Limestone Alps, at the deep boreholes Vorderriß 1 and Hindelang 1, higher temperature gradients of 2.2 °C/100 m and 2.6 °C/100 m were observed, respectively. Successful thermal water development at these depths requires that hydraulically well-permeable rocks are present. To clarify this question, extensive investigations of the reservoir rocks through exploration drilling are still required. Deep geothermal energy can lead to associated seismicity. In order to quickly detect associated seismicity and to be able to react in a timely manner, seismic monitoring is required during drilling activities and during operation of the systems, whereby the accompanying seismic monitoring must be able to distinguish between natural and induced seismicity.