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.

GIS viewer for Hotlime results

HotLime’s results of mapping and characterization, estimation, comparison and prospect ranking of hydrothermal resources in deep carbonate are compiled in two principal synopses:
The results of mapping and characterization of the geothermal reservoirs after finalizing WP2 by the end of 2019, are summarized and compared in the HotLime Midterm Summary Report.
Based on these findings, play and prospect evaluation (WP3) has been implemented and deep carbonate play development strategies and impact (WP4) have been deduced, summarized in map sets on each of the eleven HotLime Case Study areas and supplemented by the hyperlinked knowledge base featuring cross-sections, reports, factsheets and the comprehensive LOD concepts vocabulary, the HotLime Geothermal Atlas. All maps therein and more spatial representations of the geothermal base assessment are also available as georeferenced, combinable and downloadable map layers in the GIS viewer for Hotlime results, retrievable also via the EGDI Metadata Catalogue.

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Work packages
WP1Coordination and Management
WP2Characterization and Mapping
WP3Play and Prospect Evaluation
WP4Deep Carbonate Play Development
WP5Knowledge Transfer
WP6Project-Project Interface
WP7IP 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 nameParticipant Legal NameCountryPerson Months
LfU (Project Lead)Bayerisches Landesamt für UmweltGermany44.0
GSIDepartment of Communications, Climate Action and Environment (GSI)Ireland38.0
TNONederlandse Organisatie voor Toegepast-Natuurwetenschappelijk OnderzoekThe Netherlands19.25
VITOVlaams Instituut voor Technologisch Onderzoek acting as a third party of Vlaams Planbureau voor Omgeving (VLO)Belgium10.0
GBAGeologische BundesanstaltAustria6.75
LGRBRegierungspräsidium FreiburgGermany36.0
ISPRAIstituto Superiore per la Protezione e la Ricerca AmbientaleItaly21.5
GeoZSGeološki zavod SlovenijeSlovenia7.2
RER-SGSSServizio Geologico, Sismico e dei Suoli della Regione Emilia RomagnaItaly11.0
HGI-CGSHrvatski geološki institut – Croatian Geological SurveyCroatia20.0
OPMOffice of the Prime MinisterMalta4.0
ARPAPAgenzia Regionale per la Protezione Ambientale del PiemonteItaly11.0
GEOINFORMState Research and Development Enterprise State Information Geological Fund of UkraineUkraine1.22
CGSČeská geologická službaCzech Republic4.0
RURegione Umbria – Servizio GeologicoItaly2.7
ICGCInstitut Cartogràfic i Geològic de CatalunyaSpain13.86

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

Geothermal project Icking, one ca. 4,500 m TDV doublet for 30 MWe power generation.

Cirka 3,000 m TVD triple doublet project München Süd for 50 MWt district heating.