Andrej Lapanje

The state of exploitation of geothermal energy and some interesting achievements in geothermal research and development in the world

The article presents the latest status of geothermal energy use worldwide and the comparison with the previous period, both in electricity generation as well as in the various categories of direct use. Electricity production takes place in 26 countries and has at the end of 2014 reached 73,700 GWh from geothermal power plants with nearly 12.8 GW of installed power. This is still only 0.31 % of the total electricity produced in the world and it will be interesting to monitor the future share of geothermal energy in doing so. In the last 5-year period the development was particularly rapid in countries where it was slower in the past and, however, with favorable geological (tectonic) conditions (Iceland, Kenya, New Zealand, Turkey, etc.). Direct use of geothermal energy covers a significant number of countries, today there are 82, although some of them are such where it takes place almost solely by geothermal (ground-source) heat pumps (GHP) on shallow subsurface energy (Finland). Installed capacity in the direct use is 70,885 MWt and geothermal energy used, including the GHP, is 592,638 TJ/year (end of 2014). Within the used energy the share of GHP dominates with 55.2 %, followed by the bathing and swimming pools complexes incl. balneology by 20.2 %, space heating by 15.0 % (the majority of it is district heating), heating of greenhouses and soil with 4.9 %, etc. The second part presents some interesting technological and scientific innovations in exploration and exploitation of geothermal energy. GEOLOGIJA 59/1, 99-114, Ljubljana 2016 http://dx.doi.org/10.5474/geologija.2016.007

Borehole MET-1/04 near Metlika, between the External and Internal Dinarides (SE Slovenia)

Raziskovalno-kaptažna vrtina MET-1/04 pri Božakovem, vzhodno od Metlike v Beli Krajini, je globoka 841 m. Namen vrtanja je bil zajeti geotermalno vodo, ki bi bila uporabljena v turisticne namene. Obmocje vrtine leži na prehodu zunajnih Dinaridov, ki so v splosnem zgrajeni iz mezozojskih plitvomorskih karbonatnih kamnin, v Notarnje Dinaride. Za slednje so znacilne predvsem globljemorske klasticne kamnine, ravno tako mezozojske starosti. Strukturna znacilnost obmocja je niz dinarsko usmerjenih narivov, ob katerih so Notarnji Dinaridi narinjeni na Zunanje. Sama vrtina je locirana v zgornjekredni flisni skladovnici, ki je odložena transgresijsko na zgornjejurske apnence. Flisno skladovnico do globine 182, 5 m sastevljajo breca, konglomerat ter kalkarenit in lapor. Navzdol do globine 275 m sledijo spodnjekredni apnenci, ki pripadajo ali velikim olistolitnim blokom v bazi flisa ali pa tektonskemu bloku v narivni luski. Do dna vrtine na 841 m nastopaju grebenski apneci zgornjejurske starosti. Zgornji del apnecev pripada zgornjemu malmu, spodnji del pa je mogoce že spodnjemalmske starosti. V vrtini sta bili ugotovljeni dve vodonosni coni in sicer v intervalu od 92.5 do 184 m ter v intervalu od 220 do 355 m.