Mapping and Assessment of Geothermal Plays in Deep Carbonate Rocks – Cross-domain Implications and Impacts (Hotlime)


Hydrothermal systems in deep carbonate bedrock are among the most promising low-enthalpy geothermal plays across Europe. Apart from a few areas where viability of hydrothermal heat and power generation has been proved, most deep carbonate bedrock has received relatively little attention, because such rocks are perceived as ‘tight’. Exploration and development of the deep subsurface is an acknowledged high-risk investment, particularly in low-enthalpy systems, where tapping suitable temperatures for geothermal energy commonly requires drilling to depths of more than 3 km. In order to de-risk these challenging geothermal plays, it is crucial to improve our understanding of geological conditions that determine the distribution and technical recoverability of their potential resources. The efficacy of carbonate-bedrock geothermal plays is crucially dependent on groundwater yield controlled by fracture conduits and karstification. This project will identify the generic structural controls in deep carbonate formations, through a comparison of geological situations and their structural inventory, as well as collation of deep borehole data and their petro- and hydro-physical characteristics. A consistent assessment and the sharing of knowledge – bringing all partners to a common high level – will result in uniformly applicable best practice workflows for estimation, comparison and prospectranking of hydrothermal resources in deep carbonate bedrock. Applied in specific target areas by means of 2D or 3D mapping and characterization, these spatial assessments will help in de-risking the setup or maturation of regional plays, will reveal possible cross-domain implications, and will support sustainable subsurface management.

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Through this viewer the results of the Hotlime project will be made accessible when they will be available through the project. The current view is not showing results of the project but is only here to give an idea about and where the results will appear and on which technology (the EGDI)

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Project website

Further details about the project will be available later.

Work packages

WP1: Coordination and Management
WP2: Characterization and Mapping
WP3: Play and Prospect Evaluation
WP4: Deep Carbonate Play Development
WP5: Knowledge Transfer
WP6: Project-Project Interface
WP7: IP Interface

Budget and partners

The total budget of HotLime is 1,658,728.23 € of which the participants contribute 1,166,086.52 € and the EC contributes 492,641.71 €.

The participants and their contributions in terms of Person Months are:


Partner short name Participant Legal Name Country Person Months
LfU (Project Lead) Bayerisches Landesamt für Umwelt Germany 44.0
GSI Department of Communications, Climate Action and Environment (GSI) Ireland 38.0
TNO Nederlandse Organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek The Netherlands 19.25
VITO Vlaams Instituut voor Technologisch Onderzoek acting as a third party of Vlaams Planbureau voor Omgeving (VLO) Belgium 10.0
GBA Geologische Bundesanstalt Austria 6.75
LGRB Regierungspräsidium Freiburg Germany 36.0
ISPRA Istituto Superiore per la Protezione e la Ricerca Ambientale Italy 21.5
GeoZS Geološki zavod Slovenije Slovenia 7.2
RER-SGSS Servizio Geologico, Sismico e dei Suoli della Regione Emilia Romagna Italy 11.0
HGI-CGS Hrvatski geološki institut – Croatian Geological Survey Croatia 20.0
OPM Office of the Prime Minister Malta 4.0
ARPAP Agenzia Regionale per la Protezione Ambientale del Piemonte Italy 11.0
GEOINFORM State Research and Development Enterprise State Information Geological Fund of Ukraine Ukraine 1.22
CGS Česká geologická služba Czech Republic 4.0
RU Regione Umbria – Servizio Geologico Italy 2.7
ICGC Institut Cartogràfic i Geològic de Catalunya Spain 13.86


The HotLime partners and stakeholder visiting hot lime E&P drillings in southern Bavaria on occasion of the September 17-19, 2018 WP2 workshop in Augsburg.
Left: Geothermal project Icking, one ca. 4,500 m TDV doublet for 30 MWe power generation.
Below: Ca. 3,000 m TVD triple doublet project München Süd for 50 MWt district heating. 

Picture credit: HotLime, G.W. Diepolder (LfU)