The coastal plain of Rio Grande do Sul state, in Brazil, is highly vulnerable to expected changes in sea level, while having an increasing population and consequently increasing water demands. Adequate management is essential to restrain contamination, depletion and salinization of the region’s aquifers considering current and future challenges, but geologic knowledge is essential to guide groundwater sustainable practices. To contribute to this discussion, this work integrated existing geological data from the northern coast of Rio Grande do Sul state to create a three-dimensional representation of the main hydrostratigraphical units of the region and its relation to the basement rocks, expanding the current knowledge of the coastal aquifer system. A review of existing data was carried out, consisting of 307 borehole logs from 13 municipalities inside the area of interest, as well as 19 vertical electrical soundings and 37 logs from oil and coal exploratory drillings, that resulted in 315 input points for the model. This work builds up on the conceptual model previously developed for the area, that defined four hydrostratigraphical units for the region, and was able to constrain the geometries of the main aquifers (unit 1 and 3) and aquitards (unit 2 and 4) and their relation to the basement rocks, showing them to be more heterogeneous in thicknesses and extent than previously thought. In addition, this work was able to model what could be a fifth hydrostratigraphical unit, that strongly differs from the other four and could be an indication of the alluvial fans previously described in the literature.

Space and water heating for residential and commercial buildings amount to a third of the European Union’s total final energy consumption. Approximately 75% of the primary energy is still produced by burning fossil fuels, leading to high greenhouse gas emissions in the heating sector. Therefore, policymakers increasingly strive to trigger investments in sustainable and low-emission heating systems. This study forms part of the “Roll-out of Deep Geothermal Energy in North-West-Europe”-project and aims at quantifying the spatial heat demand distribution in the Interreg North-West-Europe region. An open-source geographic information system and selected Python packages for advanced geospatial processing, analysis, and visualization are utilized to constrain the maps. These were combined, streamlined, and optimized within the open-source Python package PyHeatDemand. Based on national and regional heat demand input data, three maps are developed to better constrain heat demand at a high spatial resolution of 100 m × 100 m (=1 ha) for the residential and commercial sectors, and for both together (in total). The developed methodology can not only be applied to transnational heat demand mapping but also on various scales ranging from city district level to states and countries. In addition, the workflow is highly flexible working with raster data, vector data, and tabular data. The results reveal a total heat demand of the Interreg North-West-Europe region of around 1700 TWh. The spatial distribution of the heat demand follows specific patterns, where heat demand peaks are usually in metropolitan regions like for the city of Paris (1400 MWh/ha), the city of Brussels (1300 MWh/ha), the London metropolitan area (520 MWh/ha), and the Rhine-Ruhr region (500 MWh/ha). The developed maps are compared with two international projects, Hotmaps and Heat Roadmap Europe’s Pan European Thermal Atlas. The average total heat demand difference from values obtained in this study to Hotmaps and Heat Roadmap Europe is 24 MWh/ha and 84 MWh/ha, respectively. Assuming the implementation of real consumption data, an enhancement in spatial predictability is expected. The heat demand maps are therefore predestined to provide a conceptual first overview for decision-makers and market investors. The developed methods will further allow for anticipated mandatory municipal heat demand analyses.

The provision of climate-neutral, sustainable, and independent heat sources is an essential part of the ongoing transformation of heating systems in Germany. The city of Minden, located at the junction of the river Weser and the Middleland Canal, with its strong industrial sector, faces a massive transition of how heat and energy will be provided for industrial processes as well as heating in the commercial and residential sectors. In our study, we evaluate the structural requirements for the exploitation and utilization of deep geothermal energy from regional Mesozoic rocks, which are known to source thermal springs in the greater Minden area, and geothermal projects in other parts of the North German Basin. The compilation of geological data, seismic data, and rock properties from wells is used to construct a regional structural model as well as temperature distributions based on depth uncertainties of the respective stratigraphic units. Our investigations indicate several stratigraphic units ranging from the Middle Jurassic, Keuper, and Muschelkalk to the Middle Bunter at depths greater than 4100 m below mean sea level with suitable temperatures greater than 150 ^∘C. Seismic data reveal the presence of faults, which may act as a conduit for thermal waters in the northern part of Minden. Our study also provides a basis for further geothermal exploration and exploitation south of Minden, where an operating geothermal system has already been established in the city of Osnabrück and further north, where the potential reservoirs are located at greater depths as shown by hydrocarbon exploration data. First estimations of the geothermal power output for two selected reservoir horizons yield up to 11.3 and 14.3 MW (10 % probability to yield these or higher values), respectively. We conclude that the subsurface of the inverted part of the Lower Saxony Basin principally fulfills the requirements (formation temperatures) for deep geothermal production not only for residential and commercial use but also for industrial processes. However, future detailed reservoir analyses and thermo-hydraulic investigations on a regional scale require additional exploration work like newly acquired seismic surveys and deep exploration wells.

Vintage seismic lines from the area of the city of Aachen from the early 1980s were reprocessed and interpreted in order to characterize the deeper subsurface for its geothermal energy potential. In focus are Lower Carboniferous and Middle to Upper Devonian carbonates as possible karstification is assumed due to the occurrence of thermal springs in the region. Further, extensional NW-SE striking faults of the Tertiary Lower Rhine Graben Rift may provide opportunities for geothermal field development.The Paleozoic units northwest of the Variscan Rhenish Massif range from Lower Devonian to Upper Carboniferous. Upper Devonian to Upper Carboniferous strata was thrusted onto folded Upper Carboniferous rocks of the foreland molasse basin (e.g. Wurm Syncline) during the Variscan orogeny. As a result, a complex tectonized belt with (at least) three major NE-SW striking thrusts developed, which are cropping out in the region of the city of Aachen. Later, during Upper Cretaceous and Cenozoic times, the region experienced SW-directed rifting and block faulting orthogonal to the Variscan strike as well as inversion movements. Along two of these Paleozoic thrusts, the Aachen Thermal Springs are arising from the subsurface with a temperature of up to 72°C assuming pathways for thermal water from karstified rocks in the deeper subsurface of the Inde Synclinorium. In addition, the strata is exposed along the margins of the Inde Synclinorium or was encountered in wells such as the RWTH-1 well located in the Wurm Syncline or Frenzer Staffel 1 in the Inde Syncline. While the stratigraphy of the geological units is well known from outcrops, their facies distribution and related lithology in the subsurface and within the different fault blocks of the thrust system remains fairly unknown. This was shown from the drilling of the well RWTH-1 in 2004 where the Kohlenkalk (platform carbonates) and the Massenkalk (reef carbonates) were expected but not encountered despite cropping out 10 kilometers to the southwest.For this investigation, two roughly NW-SE trending seismic lines (~70 km long) were interpreted. The lines were acquired perpendicular to the strike of the Variscan structural elements. The seismic data imaging is challenging due to highly consolidated rocks and very high impedances, partly steep inclination of bedding planes due to thrusting and back-thrusting, low angle faulting (thrust planes), and possible 3D effects where migration is difficult. However, based on the new processing, surface geology correlation, integration of well data, and back-stripping check-ups, we were able to map the key thrust outlines at depths and lithology targets based on their characteristic reflectivity pattern. The most prominent feature on the seismic data is a sharp reflection, which dips approx. south from a very shallow level (~1.000 m) below 6.000 m. The feature was also evident on vintage DEKORP-data and is interpreted as the seismic expression of the Aachen Thrust. Current models can thus be validated or adapted based on our sweet spot maps including the deeper tectonic fabric of the region and regional distribution of carbonate sequences with possible insights on karstification to de-risk future geothermal developments in the area.