Geothermal Energy Use, Country Update for Slovakia
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European Geothermal Congress 2019 Den Haag, The Netherlands, 11-14 June 2019 Geothermal Energy Use, Country Update for Slovakia Branislav Fričovský1, Radovan Černák1, Daniel Marcin1, Veronika Blanárová2, Katarína Benková1, Ondrej Pelech3, Marián Fendek4 1 Dept. of Hydrogeology and Geothermal Energy, Dionýz Štúr State institute of Geology, Mlynská dolina 1, 817 04 Bratislava, Slovakia 2 Directorate of Geology and Natural Resources, Ministry of Environment of the Slovak Republic, Bukurešťská 4, 811 04 Bratislava, Slovakia 3 Dept. of Geology of older geological units, Dionýz Štúr State institute of Geology, Mlynská dolina 1, 817 04 Bratislava, Slovakia 4 Hydrofen s.r.o., Jasovská 7, 851 07 Bratislava, Slovakia [email protected] Keywords: geothermal energy, direct use, resources and reserves, legislation, Slovakia. 1. INTRODUCTION ABSTRACT Although plans, strategies and legislative actions were Slovakia is a part of the Western Carpathians realm, an adopted, the Slovak Republic is still the fossil-fuels orogeny controlling geothermic activity of the territory oriented economy with roughly 19 % share of RES on through geological development, geodynamics and a primary energy mix. A proportion of geothermal deep geological structure. Because of any recent energy on heat production reaches app. 2 % only. volcanic activities, the entire territory of the country is of a moderate geothermic activity, with mean A systematic research and utilization of geothermal geothermal gradient of app. 30 °C.km-1 and 82.1 resources has been launched in 70’s, responding to mW.m-2. Low to moderate enthalpy (up to 150 °C) global concerns in fuels economics. However, a single-phase, geothermal waters have been successfully tradition in use of geothermal energy dates far beyond sampled of low, to moderate-low thermodynamic Medievals, owing to dozens thermal springs. quality. Recently, geothermal waters have been identified in This explains exclusively direct use of geothermal 204 wells across the Slovakia, associated amongst 27 resources in Slovakia. Since a systematic research, geothermal water bodies (GWBs) or prospective areas prospection and development in geothermal energy has (GPAs)- as reported in previous updates. Transition been launched, in total 6,233 MWt have been assessed towards GWBs meets calls of the Water Framework as probable and 406 MWt as proven wells 227 wells, Directive No. 2000/60/EC of the EU Parliament and the including those producing geothermal waters for Council. Still, the coverage counts app. 30 % of the curative purposes in dedicated spas. territory of the Slovak Republic. According to carried regional hydrogeothermal assessments, the reserves Recently, the reporting database is under a complete may count 6,233 MWt as probable, with another up to reconstruction. Summarizing data provided a total 406 MWt proven already. No regional / national scale number of 115 active wells at 76 localities. A nameplate booking has been conducted yet. Following global capacity of online wells is 228 MWt. Data collected trends, heat pump installations and use of shallow from private operators’ reports to the Water Research geothermal energy potential grow rapidly in the Institute yield a yearly production of 1,628 TJ and 452 country, with real capacity data inaccessible. GWh,t in 2017. This does not include energy and installed capacity of large-scale heat pumps and small 2. GEOLOGY AND REGIONAL GEOTHERMICS GSHP and BHHE, because of missing relative data. 2.1 Review on regional geology Recreation prevails in utilization of geothermal energy Slovakia is part of the Western Carpathians; the thrust- in Slovakia, with 60 wells serving 37 localities. Four belt formed through the Variscan – Alpine orogeny district heating systems operate now. Since 2016, two (Jurewicz, 2005) in the northern branch of the European more geothermal wells in Poľný Kesov and Veľký Alpine mountain chain (Schmid et al., 2008, Plašienka, Meder have been commissioned. No official projects 2018), comprising north-vergent crystalline thick- are in process of licensing, considering geothermal skinned and sedimentary thin-skinned nappe superunits power production in the country. (Prokešová et al., 2012). In the present picture, the Western Carpathians are divided into the Internal and 1 Fričovský et al. External (Mišík, 1997). The Internal Western structures at footslopes of Neogene volcanic Carpathians (IWC) representing complex thick-skinned mountains: open to semi-open type; petrogenic basement and cover nappes formed during the Jurassic type of chemistry; natural recharge at slopes of and Cretaceous collision. The External Western volcanic systems; reservoirs in Neogene Carpathians (EWC) consisting of thin-skinned nappes volcanoclastics and sedimentary formations, were deformed during the Neogene. The prevailing primary reservoirs most probably in Mesozoic volume of the EWC is formed by the Carpathian Flysch carbonates; fault-plane and lateral-leakage Belt, composed largely of syn-orogenic mass transport systems; (e.g. Central Slovakian Neovolcanites) deposits, and the Pieniny Klippen Belt a complex shear zone and the dividing line between the EWC and IWC. structures associated with Neogene sedimentary The IWC south of the Pieniny Klippen Belt are basins: open to close, petrogenic to mixed characterized by the Miocene basin and range structure chemistry; natural leakage (if any) at regional of the Core mountains Belt, related to the evolution of peripheries; stratified-reservoirs and basin- the Pannonian basin. On the south-east, the Vepor and constriction types; reservoirs in Neogene Gemer Belts represent remnants of the Variscan (early siliciclastics or Mesozoic carbonates; e.g. (CDDP, Paleozoic) crystalline basement overridden by Meliata- Rimava Basin, Lúčenec Basin) Hallstatt ocean derived Mesozoic nappes (Meliaticum and Silicicum), often characterized by thick Triassic Outline of geothermic activity in the Western carbonate sequences. Other characteristic feature of the Carpathians follows: add 1: different structure and Western Carpathians is the Central Carpathian depths of neotectonic block with a manifest in overall Paleogene Basin transgressively overlying IWC nappes crustal thickness; add 2: non-uniform mantle in the central and eastern Slovakia (e.g. Podtatranská propagation; add 3: spatial distribution of Neogene – kotlina basin). The Miocene–Quaternary sediments of Quaternary volcanism; add 4: local and regional the Pannonian basin system reach particularly high hydrogeological conditions; add 5: course and depth- thickness in the Vienna, Danube and East Slovak seating of major crustal fault systems (Fendek et al., basins. The Miocene extension was accompanied by 1999; Franko – Melioris, 1999). substantial volcanism (Neovolcanites) mostly of The surface heat flow density varies 50-120 mW.m-2 (, Miocene–Pliocene age found in central and eastern with a mean of 82.1 ± 20 mW.m-2 (Bodiš et al., 2017). Slovakia. Highest geothermic activity is repeatedly documented within Eastern Slovakian Neogene Basin (90-130 2.2 Regional hydrogeothermics, origin and mW.m-2) and Central depression of the Danube Basin chemistry of geothermal waters (> 90 mW.m-2), decreasing slightly within tertiary Owing to geodynamic evolution and deep geological intramountain depressions (40-70 mW.m-2), whilst structure, geothermal resources associate with regional minima (30-50 mW.m-2) are recorded from the conduction-dominated orogenic belt / foreland basin Outer Flysch zone (Marcin et al., 2014; Majcin et al., play types (Moeck, 2014). The Beša-Čičarovce 2017). structure appears an exception, assuming the magmatic intrusion type (Moeck – Beardsmore, 2014). However, 2.3 Geothermal waters, origin and quality this system has not been subjected to a regional Single-phase, low to moderate-low exergetic quality hydrogeothermal evaluation yet. (SExI = 0.05-0.145) geothermal waters were Apparently, several sub-types or concepts may be successfully proven in wells (Fričovský et al. 2018a,b), recognized for hydrogeothermal structures, not yet with temperatures through screened reservoir depths officially catalogued: (tens to 3,600 m) of 20-150 °C (Černák et al., 2014). Geothermal models (regional or local) do, however, structures associated with intramountain assume extending of a reservoir dry-rock temperatures depressions: usually hydrogeologically open, with at 4,000-6,000 m up to 180-240 °C (Fričovský et al., petrogenic type of chemistry; natural recharge at 2019; Majcin et al., 2017). hydrogeological massifs at periphery; reservoirs in Mid Triassic; basin-constriction, fault-plane, The geothermal waters are principially of marinogenic lateral-leakage and bedrock-high systems (e.g. (originally seawater, or degraded), petrogenic Liptov Basin, Levoča Basin –S,W part) (originally meteoric with various degree of vertical circulation) and mixed origin with complex chemistry structures associated with embayments of Neogene (Bodiš et al., 2018). Thus, the TDS extends widely, sedimentary basins: typically open to closed; between 0.4-90 g.l-1 (Marcin et al., 2014). petrogenic to mixed type of chemistry; natural recharge at hydrogeological massifs at periphery or 3. LEGISLATION CONTROLS ON GEOTHER- through lateral inflow; reservoirs in Mid Triassic MAL ENERGY RESEARCH, DEVELOPMENT, carbonates, Paleogene detritic carboates and USE AND PROMOTION IN SLOVAKIA conglomerates, Neogene sands and sandstones; A situation and status of RES share on PEM takes stratified-reservoirs, lateral-leakage,