Coupled surface to deep Earth processes: Perspectives from TOPO-EUROPE with an emphasis on climate- and energy-related societal challenges

Understanding the interactions between surface and deep Earth processes is important for research in many diverse scientific areas including climate, environment, energy, georesources and biosphere. The TOPO-EUROPE initiative of the International Lithosphere Program serves as a pan-European platform for integrated surface and deep Earth sciences, synergizing observational studies of the Earth structure and fluxes on all spatial and temporal scales with modelling of Earth processes. This review provides a survey of scientific developments in our quantitative understanding of coupled surface-deep Earth processes achieved through TOPO-EUROPE. The most notable innovations include (1) a process-based understanding of the connection of upper mantle dynamics and absolute plate motion frames; (2) integrated models for sediment source-to-sink dynamics, demonstrating the importance of mass transfer from mountains to basins and from basin to basin; (3) demonstration of the key role of polyphase evolution of sedimentary basins, the impact of pre-rift and pre-orogenic structures, and the evolution of subsequent lithosphere and landscape dynamics; (4) improved conceptual understanding of the temporal evolution from back-arc extension to tectonic inversion and onset of subduction; (5) models to explain the integrated strength of Europe's lithosphere; (6) concepts governing the interplay between thermal upper mantle processes and stress-induced intraplate deformation; (7) constraints on the record of vertical motions from high-resolution data sets obtained from geo-thermochronology for Europe's topographic evolution; (8) recognition and quantifications of the forcing by erosional and/or glacial-interglacial surface mass transfer on the regional magmatism, with major implications for our understanding of the carbon cycle on geological timescales and the emerging field of biogeodynamics; and (9) the transfer of insights obtained on the coupling of deep Earth and surface processes to the domain of geothermal energy exploration. Concerning the future research agenda of TOPO-EUROPE, we also discuss the rich potential for further advances, multidisciplinary research and community building across many scientific frontiers, including research on the biosphere, climate and energy. These will focus on obtaining a better insight into the initiation and evolution of subduction systems, the role of mantle plumes in continental rifting and (super)continent break-up, and the deformation and tectonic reactivation of cratons; the interaction between geodynamic, surface and climate processes, such as interactions between glaciation, sea level change and deep Earth processes; the sensitivity, tipping points, and spatio-temporal evolution of the interactions between climate and tectonics as well as the role of rock melting and outgassing in affecting such interactions; the emerging field of biogeodynamics, that is the impact of coupled deep Earth – surface processes on the evolution of life on Earth; and tightening the connection between societal challenges regarding renewable georesources, climate change, natural geohazards, and novel process-understanding of the Earth system

Assessing the prospective resource base for enhanced geothermal systems in Europe

In this study the resource base for EGS (enhanced geothermal systems) in Europe was quantified and economically constrained, applying a discounted cash-flow model to different techno-economic scenarios for future EGS in 2020, 2030, and 2050. Temperature is a critical parameter that controls the amount of thermal energy available in the subsurface. Therefore, the first step in assessing the European resource base for EGS is the construction of a subsurface temperature model of onshore Europe. Subsurface temperatures were computed to a depth of 10km below ground level for a regular 3-D hexahedral grid with a horizontal resolution of 10km and a vertical resolution of 250m. Vertical conductive heat transport was considered as the main heat transfer mechanism. Surface temperature and basal heat flow were used as boundary conditions for the top and bottom of the model, respectively. If publicly available, the most recent and comprehensive regional temperature models, based on data from wells, were incorporated. With the modeled subsurface temperatures and future technical and economic scenarios, the technical potential and minimum levelized cost of energy (LCOE) were calculated for each grid cell of the temperature model. Calculations for a typical EGS scenario yield costs of EUR 215MWh−1 in 2020, EUR 127MWh−1 in 2030, and EUR 70 MWh−1 in 2050. Cutoff values of EUR 200MWh−1 in 2020, EUR 150MWh−1 in 2030, and EUR 100MWh−1 in 2050 are imposed to the calculated LCOE values in each grid cell to limit the technical potential, resulting in an economic potential for Europe of 19 GWe in 2020, 22 GWe in 2030, and 522 GWe in 2050. The results of our approach do not only provide an indication of prospective areas for future EGS in Europe, but also show a more realistic cost determined and depth-dependent distribution of the technical potential by applying different well cost models for 2020, 2030, and 2050

Production-Induced Subsidence at the Los Humeros Geothermal Field Inferred from PS-InSAR

Surface deformation due to fluid extraction can be detected by satellite-based geodetic sensors, providing important insights on subsurface geomechanical properties. In this study, we use Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to measure ground deformation due to fluid extraction at the Los Humeros Geothermal Field (Puebla, Mexico). Our main goal is to reveal the pressure distribution in the reservoir and to identify reservoir compartmentalization, which can be important aspects for optimizing the production of the field. The result of the PS-InSAR (Persistent Scatterer by Synthetic Aperture Radar Interferometry) analysis shows that the subsidence at the LHGF was up to 8 mm/year between April 2003 and March 2007, which is small relative to the produced volume of 5×106 m3/year. The subsidence pattern indicates that the geothermal field is controlled by sealing faults separating the reservoir into several blocks. To assess if this is the case, we relate surface movements with volume changes in the reservoir through analytical solutions for different types of nuclei of strain. We constrain our models with the movements of the PS points as target observations. Our models imply small volume changes in the reservoir, and the different nuclei of strain solutions differ only slightly. These findings suggest that the pressure within the reservoir is well supported and that reservoir recharge is taking place.</p

Production-induced subsidence at the los humeros geothermal field inferred from PS-InSAR

Surface deformation due to fluid extraction can be detected by satellite-based geodetic sensors, providing important insights on subsurface geomechanical properties. In this study, we use Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to measure ground deformation due to fluid extraction at the Los Humeros Geothermal Field (Puebla, Mexico). Our main goal is to reveal the pressure distribution in the reservoir and to identify reservoir compartmentalization, which can be important aspects for optimizing the production of the field. The result of the PS-InSAR (Persistent Scatterer by Synthetic Aperture Radar Interferometry) analysis shows that the subsidence at the LHGF was up to 8 mm/year between April 2003 and March 2007, which is small relative to the produced volume of 5×106 m3/year. The subsidence pattern indicates that the geothermal field is controlled by sealing faults separating the reservoir into several blocks. To assess if this is the case, we relate surface movements with volume changes in the reservoir through analytical solutions for different types of nuclei of strain. We constrain our models with the movements of the PS points as target observations. Our models imply small volume changes in the reservoir, and the different nuclei of strain solutions differ only slightly. These findings suggest that the pressure within the reservoir is well supported and that reservoir recharge is taking place

Scenarios for geothermal energy deployment in Europe

The use of geothermal energy in Europe is expected to grow rapidly over the next decades, since this energy resource is generally abundant, ubiquitous, versatile, low-carbon, and non-intermittent. We have expanded and adapted the integrated assessment model TIAM-ECN to more adequately reflect geothermal energy potentials and to better represent the various sectors in which geothermal energy could possibly be used. With the updated version of TIAM-ECN, we quantify how large the share of geothermal energy in Europe could grow until 2050, and analyze how this expansion could be stimulated by climate policy and technological progress. We investigate geothermal energy’s two main applications: power and heat production. For the former, we project an increase to around 100–210 TWh/yr in 2050, depending on assumptions regarding climate ambition and cost reductions for enhanced geothermal resource systems. For the latter, with applications in residential, commercial, industrial, and agricultural sectors, we anticipate under the same assumptions a rise to about 880–1050 TWh/yr in 2050. We estimate that by the middle of the century geothermal energy plants could contribute approximately 4–7% to European electricity generation. We foresee a European geothermal energy investment market (supply plus demand side) possibly worth about 160–210 billion US$/yr by mid-century

Scenarios for geothermal energy deployment in Europe

The use of geothermal energy in Europe is expected to grow rapidly over the next decades, since this energy resource is generally abundant, ubiquitous, versatile, low-carbon, and non-intermittent. We have expanded and adapted the integrated assessment model TIAM-ECN to more adequately reflect geothermal energy potentials and to better represent the various sectors in which geothermal energy could possibly be used. With the updated version of TIAM-ECN, we quantify how large the share of geothermal energy in Europe could grow until 2050, and analyze how this expansion could be stimulated by climate policy and technological progress. We investigate geothermal energy’s two main applications: power and heat production. For the former, we project an increase to around 100–210 TWh/yr in 2050, depending on assumptions regarding climate ambition and cost reductions for enhanced geothermal resource systems. For the latter, with applications in residential, commercial, industrial, and agricultural sectors, we anticipate under the same assumptions a rise to about 880–1050 TWh/yr in 2050. We estimate that by the middle of the century geothermal energy plants could contribute approximately 4–7% to European electricity generation. We foresee a European geothermal energy investment market (supply plus demand side) possibly worth about 160–210 billion US$/yr by mid-century

Production-induced subsidence at the los humeros geothermal field inferred from PS-InSAR

Surface deformation due to fluid extraction can be detected by satellite-based geodetic sensors, providing important insights on subsurface geomechanical properties. In this study, we use Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to measure ground deformation due to fluid extraction at the Los Humeros Geothermal Field (Puebla, Mexico). Our main goal is to reveal the pressure distribution in the reservoir and to identify reservoir compartmentalization, which can be important aspects for optimizing the production of the field. The result of the PS-InSAR (Persistent Scatterer by Synthetic Aperture Radar Interferometry) analysis shows that the subsidence at the LHGF was up to 8 mm/year between April 2003 and March 2007, which is small relative to the produced volume of 5×106 m3/year. The subsidence pattern indicates that the geothermal field is controlled by sealing faults separating the reservoir into several blocks. To assess if this is the case, we relate surface movements with volume changes in the reservoir through analytical solutions for different types of nuclei of strain. We constrain our models with the movements of the PS points as target observations. Our models imply small volume changes in the reservoir, and the different nuclei of strain solutions differ only slightly. These findings suggest that the pressure within the reservoir is well supported and that reservoir recharge is taking place

Production-Induced Subsidence at the Los Humeros Geothermal Field Inferred from PS-InSAR

Surface deformation due to fluid extraction can be detected by satellite-based geodetic sensors, providing important insights on subsurface geomechanical properties. In this study, we use Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to measure ground deformation due to fluid extraction at the Los Humeros Geothermal Field (Puebla, Mexico). Our main goal is to reveal the pressure distribution in the reservoir and to identify reservoir compartmentalization, which can be important aspects for optimizing the production of the field. The result of the PS-InSAR (Persistent Scatterer by Synthetic Aperture Radar Interferometry) analysis shows that the subsidence at the LHGF was up to 8 mm/year between April 2003 and March 2007, which is small relative to the produced volume of 5×106 m3/year. The subsidence pattern indicates that the geothermal field is controlled by sealing faults separating the reservoir into several blocks. To assess if this is the case, we relate surface movements with volume changes in the reservoir through analytical solutions for different types of nuclei of strain. We constrain our models with the movements of the PS points as target observations. Our models imply small volume changes in the reservoir, and the different nuclei of strain solutions differ only slightly. These findings suggest that the pressure within the reservoir is well supported and that reservoir recharge is taking place.Mathematical Geodesy and Positionin

Subsurface temperature model of the Hungarian part of the Pannonian Basin

Hungary is one of the most suitable countries in Europe for geothermal development, as a result of large amounts of Miocene extension and associated thermal attenuation of the lithosphere. For geothermal exploration, it is crucial to have an insight into the subsurface temperature distribution.A new thermal model of Hungary is presented extending from the surface down to the lithosphere-asthenosphere boundary (LAB) based on a new stochastic thermal modeling workflow. The model solves the heat equation in steady-state, assuming conduction as the main heat transfer mechanism. At the top and the base, we adopt a constant surface temperature and basal heat flow condition. For the calibration of the model, temperature measurements were collected from the Geothermal Database of Hungary. The model is built up in a layered structure, where each layer has its own thermal properties. The prior thermal properties and basal condition of the model are updated through the ensemble smoother with multiple data assimilation technique.The prior model shows a misfit with the observed temperatures, which is explained fundamentally by transient thermal effects and non-conductive heat transfer. Other misfits can be attributed to a-priori assumptions on thermal properties, boundary conditions, and uncertainty in the model geometry. The updated models considerably improve the prior model, showing a better fit with measured records. The updated models are capable to reproduce the thermal effect of lithospheric extension and the sedimentary infill of the Pannonian Basin. Results indicate that the hottest areas below 3. km are linked to the basement highs surrounded by deep sub-basins of the Great Hungarian Plain. Our models provide an indication on the potential sites for future EGS in Hungary and can serve as an input for geothermal resource assessment

Subsurface temperature model of the Hungarian part of the Pannonian Basin

Hungary is one of the most suitable countries in Europe for geothermal development, as a result of large amounts of Miocene extension and associated thermal attenuation of the lithosphere. For geothermal exploration, it is crucial to have an insight into the subsurface temperature distribution.A new thermal model of Hungary is presented extending from the surface down to the lithosphere-asthenosphere boundary (LAB) based on a new stochastic thermal modeling workflow. The model solves the heat equation in steady-state, assuming conduction as the main heat transfer mechanism. At the top and the base, we adopt a constant surface temperature and basal heat flow condition. For the calibration of the model, temperature measurements were collected from the Geothermal Database of Hungary. The model is built up in a layered structure, where each layer has its own thermal properties. The prior thermal properties and basal condition of the model are updated through the ensemble smoother with multiple data assimilation technique.The prior model shows a misfit with the observed temperatures, which is explained fundamentally by transient thermal effects and non-conductive heat transfer. Other misfits can be attributed to a-priori assumptions on thermal properties, boundary conditions, and uncertainty in the model geometry. The updated models considerably improve the prior model, showing a better fit with measured records. The updated models are capable to reproduce the thermal effect of lithospheric extension and the sedimentary infill of the Pannonian Basin. Results indicate that the hottest areas below 3. km are linked to the basement highs surrounded by deep sub-basins of the Great Hungarian Plain. Our models provide an indication on the potential sites for future EGS in Hungary and can serve as an input for geothermal resource assessment