Deep geothermal resources in the Pan-European Atlas of Sustainable GeoEnergy Capacities (GSEU project): The Play-based Exploration Pyramid concept

ABSTRACT: This work introduces version 1.0 of the Pan-EU Atlas of Sustainable GeoEnergy Capacities (SGC), delivered by the GSEU (Geological Service for Europe) project. It details the methodology evolving from the Play-Based Exploration Pyramid (PBEP) concept into a practical approach for sharing harmonized knowledge about deep geothermal energy potential across Europe. This Atlas aims to deliver a standardized and generalized understanding of geothermal resources, emphasizing the potential in the framework of the Europe’s sustainable energy transition. The PBEP concept of the PanEU Atlas of SGC follows a multiscale geothermal exploration approach that systematically narrows focus from a geosystem to local scale, organizing technical and scientific data from broad, low-knowledge areas to highly detailed high-knowledge regions or local targets. It aims to ensure a refined understanding of geothermal plays, improving the identification of potential areas across Europe, spanning four levels (Level 0 to Level 3) and incorporating further refined knowledge in the assessment of geothermal resource. Levels 0 and 1 GIS datasets were published along spring 2025 in the European Geological Data Infrastructure (EGDI) as version 1.0 of the Atlas. Information available includes public data from boreholes and thermal springs (Level 0), which forms the basis for Level 1 - a harmonized map highlighting favourable prospecting areas for deep-origin geothermal resources, classified according to Geothermal Play Types (GPTs). This is accompanied by a catalogue of factsheets for each delineated GPTs across EU (~ 400 in total), summarizing the generalized findings along with a report on description and metadata. This scale-dependent process will continue in version 2 of the Atlas, with Level 2 focusing on identified potential geothermal reservoirs using 1D lumped stochastic estimations for geothermal resources and medium to high heat storage potential into deep aquifers. Finally, Level 3 will provide detailed local-scale evaluations of specific targets, compiling already existing maps and models containing spatial-distributed reservoir assessed information in 2D and/or 3D.