Testing confirms >200 °C geothermal resource at Zagocha well in Croatia
Well testing at the Zagocha geothermal power project in Croatia (source: Enna Geo)
Carlo Cariaga
20 Aug 2025
Enna Geo is progressing with their geothermal power projects in Croatia, with well testing completed in Zagocha and drilling initiated in Babina Greda.
Enna Geo, a subsidiary of the Energia Naturalis (ENNA Group), has announced that testing has been completed on the Podravska Slatina GT-6beta (PSGT-6beta) geothermal well, which was drilled to a depth of 4582 meters. A maximum temperature of 211 °C was measured at the bottom of the well, and the well discharges at 180 °C at the surface.
Drilling of the PSGT-6beta started in August 2024 and was completed in March 2025. An initial production test was done, followed by additional rigless testing. This involved the collection of downhole samples of the geothermal fluid, as well as taking several downhole and surface flow measurements.
“Two downhole samples of geothermal water were collected under dynamic conditions, along with several surface samples of water and gas, which have been sent for detailed analysis to several internationally recognised geothermal laboratories (New Zealand, France, Turkey and Croatia),” explained Boris Vidos, Project Manager of GTE Zagocha.
The production well will provide the basis for the planned GTE Zagocha geothermal power plant located in Cadavica, near Slatina. With the geothermal potential now better characterized, the ENNA Geo team will begin concrete discussions with suppliers of equipment for the power plant.
Other Croatian geothermal projects in the pipeline
Enna Geo also announced the start of drilling of the exploratory well Babina Greda GT-1 (BaGGT-1) in the Babina Greda 2 geothermal exploration field. Drilling is expected to take 110 days, and temperatures of 170 °C and flowrates of up to 110 L/s are expected.
The Babina Greda geothermal field is being developed through project company Geo Power Babina Greda. The ENNA Group took over the project in 2022.
Roadblocks remain for geothermal in Croatia
In a previously published piece, Ivana Meašic, the Director of Enna Geo, discussed the challenges that the company is facing in pushing forward geothermal power projects in Croatia. This includes the lack of a public call for the allocation of a market premium for geothermal power. The company argues that market premiums have been used by other countries, such as Germany and Italy, to encourage investment in geothermal power projects.
According to ENNA Geo, all the required documentation for tendering of market premiums for the GTE Zagocha have been in place since November 2023. The lack of market premiums have delayed project implementation.
Source: ENNA
