From 2025 to 2026, the Croatian Hydrocarbon Agency (AZU) undertook a campaign to drill one exploratory geothermal well each at four sites, with local company Crosco as the drilling contractor. The results were remarkable, with commercially exploitable geothermal resources discovered at each of the four sites – Velika Gorica, Osijek, Vinkovci, and Zapresic.
As AZU CEO Marijan Krpan remarks, the 100% success rate validates that not only does Croatia have good geothermal resources, but it also has the expertise and technical capacities to locate and develop these resources. He also confirmed that there are now plans to continue the campaign in three more sites, specifically in Sisak, Karlovac, and Vukovar.
The Croatian Electric Power Company (HEP), the national power company of Croatia, has expressed interest in contributing to the development of these geothermal resources. Dražen Lovric, Director of Strategy and Development at HEP, commented that the corporation already provides heating services and invests in infrastructure in all four cities. The mayors of Vinkovci and Zapresic, as well as the Deputy Mayor of Osijek, stated that they are interested in a joint investment with HEP.
“We are given the opportunity to completely decarbonize heating in the four mentioned cities. When we talk, for example, about Velika Gorica and the exploratory well that confirmed the source of geothermal energy in that city, we can think about connecting Velika Gorica and Zagreb to a single, geothermal heating source,” said Lovric.
Although the exploratory wells have already provided valuable insight on the characteristics of geothermal resources in the cities, there is still plenty of work needed before these resources can be utilized. The first priority would be to drill reinjection wells to complement all of the wells that have already been drilled. An energy center will then have to be built, and infrastructure to connect it with the existing heating systems have to be constructed. According to AZU, about EUR 30 million will be needed just to prepare and drill the injection wells.
