Four out of four: all geothermal sites in Croatia show significant potential

Within the project titled Preparation and Exploration of Geothermal Potential in the Context of Centralized Heating, significant geothermal potential has been confirmed near Zaprešić. It is the fourth out of the four sites, following success in Velika Gorica, Osijek, and Vinkovci.

The Croatian Hydrocarbon Agency (AZU) has conducted and concluded exploration activities at all planned locations, achieving a 100% success rate and maximum project effectiveness, said President of the Management Board Marijan Krpan. It is proof of the agency’s full operational capacity, he added. Separately, think tank Ember’s new study outlined solid geothermal potential in the country.

“All results so far show that the Croatian Hydrocarbon Agency possesses the expertise, technical capacity and reliable approach to implement complex exploration works and assess underground potential. Four positive wells out of four explored locations are proof that Croatia not only has wealth beneath its feet but also experts who know how to find it. The agency has confirmed in the field that it can effectively lead strategic national projects that guarantee energy independence and security in the future. We believe that we will apply our knowledge and experience in Kazakhstan as well, as a proven partner, ready for international expansion,” noted Krpan.

Temperature near Zaprešić exceeds 95 degrees

Research in Zaprešić, near the border with Slovenia, confirmed the existence of a geothermal reservoir, developed primarily in dolomites at depths greater than 1,600 meters, with excellent properties and temperatures exceeding 95 degrees Celsius. It is a location for which there was the least geophysical and borehole data.

Exploration in the Zaprešić area, in Zagreb county, included two-dimensional (2D) seismic measurements, magnetotelluric measurements and the drilling and testing of an exploratory geothermal well.

“Just two months ago, we were in the same spot to announce the start of work on a project of exceptional importance for our citizens and economy. I am pleased that today we can confirm positive results, creating the prerequisites for a step toward sustainable and long-term solutions for our community,” Mayor of Zaprešić Željko Turk stated.

Historic results for national energy independence

Research at key locations in the Pannonian region has achieved historic results for the country’s energy independence, according to the Croatian Hydrocarbon Agency. Just last June, a reservoir temperature higher than 100 degrees was established at a site on the territory of the City of Velika Gorica. Analyses confirmed the source could meet nearly 60% of the needs of a local heating system. The investment exceeded EUR 11 million.

Next, a reservoir temperature also exceeding 100 degrees Celsius was confirmed near Osijek in August, with a capacity estimated at nearly 5 MW. The endeavor, worth over EUR 8 million, positioned Osijek as a green leader with great potential for agricultural and economic development, the new announcement reads.

Only one geothermal power plant was built in Croatia, but it has been inactive for years

Another positive result was achieved in Vinkovci late last year. At a depth of 2,700 meters, a record 131 degrees were measured, representing exceptional commercial potential for district heating and industrial applications.

The project Preparation and Exploration of Geothermal Potential in the Context of Centralized Heating is funded from the National Recovery and Resilience Plan (NRRP or NPOO), totaling EUR 50.8 million. Exploration and drilling works were carried out by Crosco, a member of INA Group.

While geothermal projects are gaining momentum, Croatia currently has no active geothermal power plants. Specifically, the Velika 1 plant in Ciglena near Bjelovar has been offline for three years due to an ownership dispute.