Exploration drilling for geothermal resources begins in Zaprešic, Croatia

Drilling rig operations at Zaprešic, Croatia (source: City of Zaprešic)

Carlo Cariaga 8 Dec 2025

Drilling of a geothermal research well in the city of Zaprešic in Croatia has officially started, following news of the permit being granted to the Croatian Hydrocarbon Agency (AZU) a few months ago. The drilling operations will target a depth of about 2700 meters, where temperature and flow measurements will be made to evaluate the viability of utilizing the potential geothermal resources.

Zaprešic is the last of four sites that had been identified by the AZU for geothermal research drilling based on prior studies and surveys. Positive findings had already been confirmed in Velika Gorica, Osijek, and Vinkovci. The results of the research drilling in Zaprešic is expected by around February 2026.

The geothermal research drilling projects are being done under the “Preparation and exploration of geothermal potential in the context of centralized heating” initiative. It is being implemented by the AZU with funding of EUR 50.8 million from the National Recovery and Resilience Plan (NRRP). About EUR 10.5 million of this funding has been allocated to Zaprešic.

Mayor Željko Turk pointed out that geothermal development  will help facilitate planned projects in the city, including a swimming pool and Fale?njak entrepreneurial zone.

“We have conducted detailed measurements and analyses at locations with geothermal potential, which have given us a good initial picture, but we can only obtain reliable data by going deeper. The expertise of our team has been confirmed at the previous three locations where the wells have yielded positive results, and we are applying the same approach in Zapreši?. Upon completion of the testing, we will have clear information about the actual geothermal potential of this area,” said Martina Tuschl, Director of the Geothermal Energy Sector of the AZU at the inauguration event.

“This is an important moment for Zaprešic. A project has begun that opens up the possibility of using our own source of clean energy and creating a modern, safe heating system. We believe in a positive outcome and look forward to the results that will show that our city can make a step forward towards a sustainable and long-term profitable solution for citizens, as well as the economy,” added Mayor Željko Turk.

Source: City of Zaprešic