Geothermal Country Update Report for Slovenia, 2020-2022

Abstract

The most geothermally exploited region in Slovenia, the Mura-Zala basin, is in northeastern part and belongs to the Pannonian Basin. No significant progress with new deep drillings was achieved there in geothermal development in direct heat use of thermal water during the last three years. However, better utilization schemes at several localities with introduction of heat exchangers and heat pumps of bigger rated power for improved geothermal heat use are in place. Most users there, tap thermal water from the Mid- to Late Miocene (Pannonian-Pontian) sand aquifer with temperatures of 36 to 66 °C. No other new direct heat user from thermal water has appeared in the country. The installed capacity and annual energy use of 29 thermal water users amounted to 58.3 MWth and 551.9 TJ in 2022, with almost no influence of Covid pandemic period. Greater progress is achieved in shallow geothermal energy use with the ground-source heat pump (GSHP) technology, where some 16,135 GSHP units (predominantly of 12 kW rated power) are operational with capacity of 260.1 MWth, which used 1294.7 TJ/yr of heat from the shallow underground (Dec. 2022). The total numbers for all applications of geothermal direct heat uses are 318.4 MWth and 1846.6 TJ/yr, respectively. It is expected the trend of energetic renovation of older buildings (including apartment blocks in cities) will continue more intensively in future, also with installation of the GSHP units, as one of the obligations to reach the renewable energy targets set by the EU directives. Faster development in use of deep geothermal is expected in 2022-2024 as two projects, supported by EEA Grants, have started: INFO-GEOTHERMAL - Supporting Efficient Cascade Use of Geothermal Energy by Unlocking Official and Public Information and Si-Geo-Electricity - Pilot geothermal power plant on an existing gas well Pg-8. We also foresee new research in cooling capabilities of geothermal within a CRP project GeoCOOL FOOD - Cold food storage using shallow geothermal energy.