Finite element simulation of permeable fault influence on a medium deep borehole thermal energy storage system

Abstract Solutions for seasonal energy storage systems are essential the reliable use of fluctuating renewable sources. As part research project SKEWS, a medium deep borehole thermal system with depth 750 m is under construction at Campus Lichtwiese in Darmstadt, Germany, to demonstrate this innovative technology. Prior design geological context surroundings location was investigated using archive drilling data and groundwater measurements. The geologic survey suggests assumption that uppermost intended domain crosscut by normal fault, which displaces Permian rocks east Darmstadt against granodioritic Odenwald crystalline complex. A 3D finite-element numerical model implemented estimate effect potentially higher hydraulic conductivity fault zone on planned system. For purpose, operation over time span 30 years simulated different parametrizations zone. simulations reveal limited but visible heat removal from region increasing flow However, section affected minor compared total This only constitutes impairment efficiency approximately 3%. In total, amount extracted varies between 320.2 GWh 326.2 models. These findings can be helpful planning assessment future fractured faulted settings providing about potential impact faults or large fractures crosscutting