State of the Art of the Geothermal Resources in Croatia in the Year 2004

Abstract

In general, there are two different regions in the Republic of Croatia both in geological and geothermal respect. The Dinaric area occupies the southeastern part of the country with predominantly Mesozoic carbonate rocks characterized by the temperature gradients ranging from 0.01 to 0.03?C/m. The northeast part of the country lies mostly in the area known as the Panon. It is dominated by clastic sedimentary rocks of Quaternary and Tertiary age that overly the crystalline bedrock and, occasionally, the Mesozoic sedimentary rocks. The temperature gradient in the latter area ranges from 0.03 to 0.07?C/m with considerable geothermal energy potential.
Altogether there are 28 reservoirs in Croatia. Only 18 of them have been utilized, although the percentage of usage of their available power is still very small. Installed capacities have a thermal power of 113 MWt, with annual energy production of 680 TJ/yr. Improvement of such a condition can be significant for the future economic development of certain regions in Croatia. Increase of direct geothermal energy usage in the past five years was about 20%, while the plans for construction of a geothermal electric power plant are postponed to year 2010.