Characteristics of geothermal
potential, current utilization and its
future (challenges) in Slovenia
Andrej Lapanje, Nina Rman, Dušan Rajver
Geological
Survey of
Slovenia
RENEXPO, Budapest, 6 May 2011
LECTURE CONTENT
 GEOTHERMAL SYSTEMS IN SLOVENIA
 GEOTHERMAL ENERGY POTENTIAL IN SLOVENIA
 GEOTHERMAL ENERGY USE IN SLOVENIA
 GEOTHERMAL ENERGY USE IN THE NE SLOVENIA
 PRESENT AND FUTURE OF GEOTHERMAL UTILIZATION IN
SLOVENIA
GEOTHERMAL SYSTEMS IN SLOVENIA
 Existence is dependant on geology, while their utilization
on economic conditions
 Potential for geothermal heat pumps utilization is not
estimated in a wider scale but utilization is applied
 In Slovenia mostly low-temperature aquifers in warm
spring, sedimentary basin and basement of
sedimentary basin systems exists
 Middle and high-temperature aquifers in sedimentary
basins and the basement are only presumed to exist
GEOTHERMAL SYSTEMS IN SLOVENIA
Various systems → different water properties → different use
and problems
SURFACE HEAT-FLOW DENSITY (mW/m2)
Thinner solid crust in the NE Slovenia –
higher than normal heat flow (>65 mW/m2)
EXPECTED TEMPERATURE AT 1 KM DEPTH
EXPECTED TEMPERATURE AT 3 KM DEPTH
Geothermal energy – POTENTIAL FOR ELECTRICITY

Indications on possible high temperature reservoirs in NE
Slovenia
→ yet to be proven
Geothermal energy – POTENTIAL FOR ELECTRICITY

Potential high temperature reservoirs:
- aquifer depth, thickness and boundaries
- water yield, wellhead and reservoir pressure and
temperature
- water chemistry
- produced energy
- reinjection

-
Mg-6
temperature 202°C at 3739 m
no hydraulic tests were performed

Possible deeper drilling in existent boreholes for evaluation
of the geothermal potential

Nearest demonstration geothermal electricity plants:
Altheim (1 MWe), Bad Blumau (0.2 MWe)
GEOTHERMAL UTILIZATION IN SLOVENIA
 Direct use
 Thermal water is in usage at 30 locations
 Capacity: 66.8 MWt (in 2010)
 Energy: 774.6 TJ (in 2010)
 > 4400 geothermal heat pumps (GHP)
- open groundwater system (W)
- closed system (H and V)
- groundwater temperature 4-20°C
 Capacity: 49.9 MWt (May 2010)
 Energy: 244 TJ (May 2010)
 Total capacity in Slovenia (June 2010): 117 MWt
 Total energy use in Slovenia (June 2010): 1019 TJ
LOCATIONS AND TYPES OF DIRECT USE IN SLOVENIA
EXAMPLES OF DIRECT USE IN SLOVENIA
Moravske Toplice –
Health resourt
Pirniče - Meditation
Dobrovnik – Orchids greenhouse
Murska Sobota –
District heating
Lendava – De-icing
Benedikt – Space heating
SHARE (%) OF GTE CAPACITY IN SLOVENIA BY FIELD (June 2010)
GTE DIRECT USE INSTALLED CAPACITY (June 2010)
GTE DIRECT USE ANNUAL ENERGY USE (June 2010)
GEOTHERMAL ENERGY USE IN NE SLOVENIA
IDENTIFIED UTILIZATION PROBLEMS IN NE SLOVENIA







Degassing of methane, CO2, H2S
Scaling
High organic matter content
Changes in chemical composition
Water-level and yields decrease, interference
Sand-clogging
Pump cavitation
IDENTIFIED UTILIZATION PROBLEMS IN NE SLOVENIA
PROJECT ADDRESSING THE GEOTHERMAL IN NE SLOVENIA
http://www.t-jam.eu
Conceptual models:
• Geological
• Hydrogeochemical
• Geothermal
•Hydrogeological
PROJECT ADDRESSING THE GEOTHERMAL IN NE SLOVENIA
http://akvamarin.geo-zs.si/t-jam_boreholes/
http://www.t-jam.eu
PROJECT ADDRESSING THE GEOTHERMAL IN NE SLOVENIA
http://transenergy-eu.geologie.ac.at/
http://akvamarin.geo-zs.si/users/
PRESENT AND FUTURE OF GEOTHERMAL IN SLOVENIA
 Geothermal energy utilization rises, especially GHP
 Strong interest in geothermal energy in the NE Slovenia
 Thermal water production rises with no reinjection applied
 Cascade use, operational and waste water monitoring are
mostly poorly applied
 Utilization problems are becoming more evident
 Geothermal electricity is questionable in Slovenia
 Investors wanted for inactive wells exploitation (Janežovci,
Mislinjska Dobrava, Turnišče, Dobrovnik, Izola…)
 Investors wanted for drilling new wells (Goriška Brda,
Zasavje, Besnica, Petišovci…)
 No national evidence on installed GHP
 No national monitoring system for deep geothermal systems
 Only rare concessions granted, no control or deadlines
Future challenges

Geologists & Drillers :
- current exploitation:
- designing unified operational and national monitoring for
sustainable production of thermal water
- dealing with aquifer changes: pressure drops, temperature
and chemistry changes, interference, aquifer response to
reinjection
- developing, modeling and testing doublet systems:
reinjection into sand and loose sandstone reservoirs
- new research:
- developing new low and high temperature geothermal sites
- exploring indicated potential high temperature deep
geothermal aquifers
- exploring EGS potential in Slovenia
- identifying potential areas for GHP’s installation, elaborating
expert basis, and estimating influence of its increasing
installation on hydrogeological conditions in shallow aquifers
Future challenges

Users & Investors:
- applying technological optimization at operating geothermal
sites: higher efficiency of heat extraction, cascade use,
prevention of scaling and degassing
- installing hybrid systems and cogeneration
- installing GHP’s in larger infrastructure objects according to
European Energy Performance of Buildings Directive (EPBD)
- implementing operational monitoring on active wells
- developing new geothermal sites

Authorities:
- enhancing national-wide geothermal and structural research by
national and regional plans (financing & conducting research)
- enhancing GHP’s and other direct use geothermal installations
by subsidies and expert support
- regulating new installations of water-water GHP’s
- issuing research and water permits and control their
implementation
- designing, maintaining and interpreting national monitoring
- interpreting and controlling operational monitoring
THANK YOU!
AFP-1/95
photo: Geoprojekt