In Germany the heat demand distribution and operational geothermal production show limited spatial overlap and this is related to the geology in the subsurface. Most of the geothermal energy projects are located in the sedimentary areas of the Molasse Basin, the Upper Rhine Graben and the North German Basin. All these areas have in common that a thermal blanketing effect of young shallow sediments with high porosity keep the heat trapped beneath the insulating porous layer. The North German Basin has an additional heat controlling element - the mobilized Zechstein salt. Salt is thermally twice as conductive as clastic sediments and acts as a chimney for heat transport. The third controlling factor is the basal heat input that depends on the depth to the thermal LAB and the thickness of the upper crystalline crust producing ragiogenic heat, thus adding up to a half to the heat budget in the basins. Finally, the coupled transport of heat and fluid and the composition of the moving fluids add a last layer of complexity in defining geothermal sweet spots. As the fluids can move fast, they can take along their heat/cold, but also may transport solved material that can precipitate and destroy permeability if the PT-regime of the solution changes. The meanwhile increasing resolution of data and structural models of the subsurface open new opposrtunities to simulate heat transport considering the heterogenous physical property distribution as well as physical processes , thus enabling predictions far beyond the interpolation of a few temperatures measurements.

The Global Heat Flow Database (GHFDB) is fostered and maintained by the International Heat Flow Commission (IHFC) for nearly 60 years. During these decades, the technological database concepts and storing capabilities evolved, allowing to add entries in the heat-flow database and underlying scientific methods according to the state of the art and database technology. In 2019, a collaborative database revision process started to provide a quality-assured and authenticated database. The community-driven approach, called the Global Heat Flow Data Assessment Project, started with a discussion of a new database structure to substitute the former database structure from 1976. It was designed to scrutinize and reassess the stored heat flow data according to the new structure. In parallel, the DFG-funded World Heat Flow Database project is developing a modern research data infrastructure for the new global compilation of heat flow data. It will offer comprehensive information on heat-flow related data, publications, projects, and researchers. It is designed to reflect the criteria of FAIR and OPEN data policy and to support the interoperability with other geoscientific data services

Deep geothermal energy (DGE) may play a crucial role in the future energy production considering its base load capacity and ubiquitous availability. The EU Interreg North-West Europe (NWE) funded project DGE-ROLLOUT aims to promote the hydrothermal potential of Lower Carboniferous carbonate rocks, which is investigated following a multi-disciplinary geoscientific approach.

Besides the Geological Survey of North Rhine-Westphalia as lead partner, project partners include the national geological surveys of Belgium, France and the Netherlands, as well as industry partners (DMT GmbH & Co. KG; Energie Beheer Nederland B.V.; RWE Power AG) and research institutions (Fraunhofer Institution for Energy Infrastructures and Geothermal Systems; Technical University Darmstadt; Flemish Institute for Technological Research). Sub- and associated partners include the national geological surveys of Great Britain and Ireland and the European Geothermal Energy Council, amongst others.

DGE-ROLLOUT comprises three administrative, one investment and three implementation work packages (WP T1-T3): T1 provides a reconciled knowledge baseline for the DGE market development in NWE, including a transnationally harmonised depth and thickness map of the Lower Carboniferous. T2 fills information gaps through the acquisition of 2D seismic surveys, drillings, reprocessing vintage seismic data, and developing 3D subsurface models. T3 increases the efficiency of existing geothermal systems, implementing new or improved production techniques regarding reservoir behaviour, cascading systems and thermal energy storage.

As DGE-ROLLOUT comes to an end in October 2023, we are keen on presenting our final results and evaluating the extent to which we succeeded in promoting the DGE potential of Lower Carboniferous carbonate rocks in NWE.

Characterizing the subsurface structural and stratigraphic configuration is critical to address current global environmental challenges such as green energy transition and underground storage. Northern Bavaria, as our case study, is mainly covered by Permo-Mesozoic sedimentary units. Local and regional thickness changes are mainly attributed to the partly exposed structural complexity. To the east, the exposed crystalline rocks consist mainly of metamorphic rocks of Variscan affinity and late to post- orogenic intrusions. The presence and extent of granitic intrusions as a source of heat production and the estimation of the depth to the base of Permo-Mesozoic sedimentary cover are the main objectives of this study.

In this study, we integrate the information from wells and exposed basement geology with reprocessed DEKORP seismic reflection, recently acquired 230 km 2D seismic reflection, Bouguer gravity anomaly and magnetic data to improve our understanding of the structural and stratigraphic configuration of the subsurface in northern Bavaria. Our first results confirm the presence of a granitic body (Hassfurt Granite) as the main source of thermal anomaly observed in northern Bavaria. We also show Permian (Rotliegend) grabens and half grabens storing 1-1.5 km thick sedimentary units. Rotliegend units are covered by relatively tabular Mesozoic cover. In structural point of view, we show that some of the Permian basin bounding normal faults are reactivated as reverse faults during the Cretaceous inversion event. Our observations and models contribute to reservoir characterization (buried fault zones and associated brittle deformation) and reduce exploration and potential future development risks.