Gradient Distribution and Geothermal Resources of Croatia
northern part of the Republic of Croatia, in geological terms a part of the Panonian
sedimentary basin, having an average temperature gradient of 0.049░C/m and vertical
conductive heat flow of 76 mW/m2 (JeliŠ et al., 1995), can be considered a large
geothermal energy accumulator.
The great majority of wells
drilled for oil or natural gas, being positive or dry in terms of hydrocarbons,
penetrated aquifers that, belonging to such a warm environment, could be considered
geothermal reservoirs. Nevertheless, taking into account technological and economic
criteria, only those producing water with temperatures above 65░C were classified
as geothermal wells.
Comparison of the total geothermal energy
that could be produced using conventional heat exchange systems with the total
primary energy production in Croatia of 198.4 PJ/yr (according to Vuk et al.,
1998), shows that an appropriate utilization of geothermal resources would ensure
their contribution of 6.7%. Comparison of the same figure with the total primary
energy supply, 348.0 PJ/yr, means the potential provides 3.8% coverage of the
energy needs of the country. In the case of heat pumps, which means we consider
geothermal water outlet temperature down to 25░C, the contribution of geothermal
to the total primary energy production and the total primary energy supply would
increase to 9.2% and 5.3%, respectively.
>> Geothermal Energy Potential and Utilization in the Republic of Croatia