--- cover-image: https://raw.githubusercontent.com/GTIF-Austria/public-assets/refs/heads/main/assets/thumbnails/klien_data/Deep%20Geothermal%20Energy.png

domain: Energy Transition tags: KLIEN,renewable energy,energy potential,energy technology,deep geothermal energy provider: AIT Center for Energy ​

Deep Geothermal Energy Potential – Study on Renewable Energy Potentials ​

Background ​

Deep geothermal energy comprises applications at depths of 300 meters and greater, where temperatures ranging from above 30°C to well over 100°C can be exploited. Deep geothermal energy has a long history in Austria and offers substantial potential, particularly for the provision of heat that is independent of diurnal and seasonal fluctuations. Through the utilization of natural thermal water resources and innovative technologies such as petrothermal (enhanced geothermal) systems, deep geothermal energy has gained increasing attention in recent years.

The potential of deep geothermal energy in Austria is considerable. Particularly promising is the integration of geothermal systems into industrial applications and district heating networks, where deep geothermal energy can provide a reliable and sustainable heat source [1].

In Austria, deep geothermal energy is almost exclusively developed as hydro-geothermal energy, i.e. through the use of natural thermal water reservoirs. Hydro-geothermal applications have been in use for nearly 50 years. The development of deep geothermal energy in Austria benefits from a long tradition and a solid foundation of geoscientific exploration data, particularly derived from more than 80 years of hydrocarbon exploration activities.

Methodology ​

The technically exploitable potential of deep geothermal energy in Austria is primarily associated with specific geological regions. Among the most significant are the Vienna Basin, the Molasse Basin in Upper Austria and Salzburg, the Styrian Basin, the Molasse Basin and Helvetic units in Vorarlberg, as well as the eastern margin of the Molasse Zone in Lower Austria.

However, Austria currently lacks a comprehensive nationwide characterization of the deep subsurface (> 300 m below ground level) that would be required for a robust assessment of deep geothermal utilization. Prior to the 3D seismic campaign conducted by Wien Energie and OMV for the development of deep geothermal energy for Vienna’s district heating network, available data largely consisted of borehole and seismic datasets originating from the hydrocarbon industry. These data are restricted to favourable areas of hydrocarbon exploration, resulting in considerable regional variability in data density across federal states, and are generally not publicly accessible. As a consequence, the potential of deep geothermal energy in many parts of Austria can currently only be estimated.

Results ​

As part of the project, an updated mapping of Austria’s hydrothermal reservoirs was carried out. The newly created map (Figure 1) shows geological formations with proven thermal‑water occurrences, for which at least one confirmed drilling was required as a criterion. These hydrothermal reservoirs are defined by a temperature threshold of more than 40°C and currently represent the main focus of deep‑geothermal utilization in Austria.

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Figure 1: Overview of hydrothermal reservoirs >40°C (blue areas), potential occurrences of thermal waters (light blue), and areas where isolated occurrences of thermal water are possible (green) in Austria. ​

Blue areas mark confirmed hydrothermal resources, while additional prospective zones (“Hoffnungsgebiete”) were identified based on geological potential, independent of existing or planned heat offtake infrastructure. Geosphere Austria also prepared detailed descriptions for each reservoir.

The map incorporates both existing well data and newly re evaluated regions:

• Light green areas show potential thermal water occurrence and possible expansion zones for future geothermal use.

• Dark green areas, mainly in alpine regions, indicate locations where thermal water may be present but where geological data are too limited for a full assessment.

Although the mapping provides a comprehensive overview of known and potential hydrothermal systems, a robust quantification of technical or realizable potentials for 2030 or 2040 was not possible due to insufficient subsurface data. Reliable assessments would require additional exploration wells, improved geophysical datasets, and advanced subsurface modelling. Thus, the updated map forms an essential foundation while clearly highlighting the need for further investigations.

Assessment of Results (Expert Judgement) ​

Because deep subsurface data in Austria remain sparse and partly inaccessible, realizable deep geothermal potentials cannot yet be calculated. Expert estimations therefore serve as the primary basis.

In the R&I Roadmap for Geothermal Energy [2], the following overview of geothermal potentials and proposed expansion targets was published.

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Figure 2 Current scope of application, identified resources, and geothermal expansion targets for 2030 and 2050 as proposed by the Austrian Geothermal Association (GTÖ). ​

Earlier studies (including GeoEnergie2050, GeoTiefEXPLORE, Transenergy) estimate Austria’s total hydrothermal potential at 400–1,200 MWth, while recent work in the central Vienna Basin indicates a sustainable technical potential of >1,000 MWth at a reinjection temperature of 70°C.

Current installed capacity stands at 104 MWth across ten heating plants, producing about 350 GWhth annually. By 2030, an additional 100 MWth could be developed (up to 1,5 TWh/year). By 2040, capacities may nearly triple, especially within district heating systems in major urban areas such as Vienna and Graz.

Estimated levelized costs of heat (LCOH) for deep geothermal systems range from 20–60 €/MWh.

In the Vienna Basin, the first deep geothermal wells (approx. 3,000 m depth) are now supplying the Vienna district heating network, with initial capacity sufficient for 20,000 households and long term goals of 200 MWth and heat supply for 200,000 households. A third geothermal power plant recently began operation in Fürstenfeld, and several expansions or new projects are underway in Upper Austria, Salzburg, and the southern Vienna Basin.

High temperature aquifer storage (HT ATES) offers new potential for seasonal storage and greater system flexibility, supporting decarbonization in heating networks and industrial processes.

Assessment and Outlook ​

While current deep‑geothermal use in Austria focuses on hydrothermal systems, this does not limit future development. Additional geothermal potential may exist outside mapped hydrothermal zones. Alternative technologies—such as deep borehole heat exchangers, closed‑loop systems, or petrothermal approaches with hydraulic stimulation—enable location‑independent geothermal use even without natural thermal‑water resources.

High‑temperature deep‑geothermal systems could play a major role in supplying district‑heating networks and industrial processes up to 120°C, or up to 200°C when combined with high‑temperature heat pumps. This would allow fossil‑free heating of entire urban districts.

Near‑surface geothermal systems complement this by serving anergy networks and decentralized supply concepts, offering modular heating and cooling solutions for residential and commercial areas.

References ​

[1] E. Haslinger und G. Götzl, „FTI-Roadmap Geothermie,“ Bundesministerium für Klimaschutz, Umwelt, Energie, Mobilität, Innovation und Technologie (BMK), Wien, 2022.

[2] Bundesministerium für Klimaschutz, Umwelt, Energie, Mobilität, Innovation und Technologie (BMK), „FTI-Roadmap Geothermie - Vision und FTI-politische Fragestellungen,“ BMK, Wien, 2022.

About ​

The underlying study, “Renewable Energy Potentials in Austria for 2030 and 2040,” was conducted on behalf of the Austrian Climate and Energy Fund and was financed with appropriations from the former Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK). It was carried out under the leadership of AIT Austrian Institute of Technology GmbH (AIT), together with the Environment Agency Austria (UBA), Vienna University of Technology (TU Wien), AEE – Institute for Sustainable Technologies (AEE INTEC), and Energiewerkstatt.

AIT acts as provider for this service.

EOX complements with its IT expertise, acting as host and front-end expert.

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