Croatia signs €35 million grant to drill geothermal wells in four cities

Overview

Updated 1 hour ago

Four Croatian cities could start heating homes from underground hot water by 2030. The government signed a €35 million grant on October 9 to drill injection wells at Velika Gorica, Osijek, Vinkovci, and Zaprešić, where test wells drilled in 2025 already confirmed usable heat.

Each site pairs an existing production well with a new injection well to form a closed loop: hot water rises, gives up its heat, and returns to the reservoir. Geothermal runs around the clock, unlike wind and solar, which suits district heating networks that need steady supply. The European Regional Development Fund covers €30 million of the cost.

Why it matters

Four Croatian cities could replace natural gas heating with domestic, always-available underground heat, cutting import dependence and exposure to energy price swings.

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Key Indicators

€35.29M

Signed grant agreement value

Of which €30 million comes from the European Regional Development Fund.

€86M+

Total two-phase investment

Adds €50.8 million in earlier National Recovery and Resilience Plan funding.

Cities with confirmed geothermal resources

Velika Gorica, Osijek, Vinkovci, and Zaprešić all passed exploration drilling.

100°C+

Water temperature at Osijek well

Well Osijek GT-1 confirmed water above 100°C and roughly 5 MW of thermal capacity.

1,700

Households Vinkovci plans to heat

The district system would also cover schools and public institutions.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Ante Šušnjar

Croatian Minister of Economy

Co-signed the grant agreement for the government

Marijan Krpan

President of the Management Board, Croatian Hydrocarbon Agency (AZU)

Leading the drilling program's next phase

Andrej Plenković

Prime Minister of Croatia

Attended the signing ceremony

Ivan Radić

Mayor of Osijek

Signed agreement for the city's injection well

Josip Romić

Mayor of Vinkovci

Signed agreement for the city's injection well

Organizations Involved

Croatian Hydrocarbon Agency (AZU)

Government Agency

Managing the drilling program

State agency that licenses and manages hydrocarbon and geothermal exploration in Croatia.

Ministry of Economy

Government Ministry

Administering the grant

Croatian ministry that ran the geothermal grant call and co-signed the funding agreement.

SAFU (Central Agency for Financing and Contracting of EU Programs and Projects)

Government Agency

Managing EU fund disbursement

State body that administers EU funding and co-signed the agreement.

HEP-Toplinarstvo

State Utility

Planned operator of district heating connections

State-owned district heating company set to link Osijek's geothermal source into the city network.

Timeline

2025 2030

7 events Latest: 3 days ago

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2030
Target year for geothermal heating
Upcoming Milestone

Government target for the four cities to begin using geothermal energy for heating.
2030
2028
Drilling of injection wells planned to begin
Upcoming Construction

AZU president Marijan Krpan says construction should start roughly two years before the 2030 target.
2028
October 2026
Grant agreement signed in Zagreb
Latest Funding

Government signs €35.29 million grant for four injection wells at the National and University Library, with €30 million from the EU.
3 days ago
August 2026
Ministry approves geothermal financing
Funding

The Ministry of Economy issues its decision to finance the four injection wells.
August 31st, 2026
June 2026
Ministry publishes geothermal grant call
Funding

The Ministry of Economy opens the call for funding to drill the four injection wells.
June 2026
2025
Osijek exploration well confirms usable heat
Exploration

Well Osijek GT-1 confirms water above 100°C and roughly 5 MW of thermal capacity at about 2 km depth.
2025
Exploration drilling runs across four sites
Exploration

The Croatian Hydrocarbon Agency drills exploration wells at Velika Gorica, Osijek, Vinkovci, and Zaprešić, confirming resources at all four.
2025

Scenarios

First city connects geothermal heat by 2030

Likely Resolves by End of 2030

Discussed by: Croatian government (Ministry of Economy, AZU) and Jutarnji list reporting

The agreement moves the four sites from confirmed resources to working doublets. If tenders run on schedule, drilling begins around 2028 and the first district heating connections follow by 2030. Osijek, where HEP-Toplinarstvo already plans grid integration, is the most advanced candidate.

Geothermal program expands to seven cities

Possible Resolves by Q2 2028

Discussed by: Ministry of Economy public statements

The Ministry has flagged geothermal potential at Karlovac, Virovitica, Križevci, Bjelovar, and Lipik, with the last three closest to realization. A public call through the Modernization Fund, worth roughly €26 million, is being prepared for them under a new law simplifying exploration permits.

Drilling slips past the 2028 start

Uncertain Resolves by End of 2028

Discussed by: No named analyst — program execution risk

The Croatian Hydrocarbon Agency had not announced the drilling tender as of the signing. Delays in procurement, permitting under the new georesources law, or funding shortfalls could push construction past the planned 2028 start and the 2030 heating target.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

1930–1970s

Reykjavik geothermal district heating (1930s–1970s)

Reykjavik began piping hot spring water into buildings in 1930, starting with a school and a pool. Over the following decades the city expanded the network, and by the 1970s it heated most of its buildings using geothermal energy instead of imported coal and oil.

Then

The city displaced coal and oil for heating within a generation.

Now

Reykjavik became the standard example of a whole city converting to geothermal, with geothermal heating now covering the vast majority of building needs.

Why this matters now

Croatia's four-city program follows the same municipal pattern, though on a smaller scale and with a faster public-funding path.

1969 onward

Melun l'Almont, France (1969)

France's first geothermal district heating plant opened in Melun in 1969, tapping the Dogger aquifer beneath the Paris Basin. It demonstrated that continental European heating networks could run on deep geothermal water.

Then

The Paris Basin saw dozens of similar geothermal heating projects in following decades.

Now

It proved the technical model of production-injection well pairs that Croatia is now adopting.

Why this matters now

France's Dogger layer and Croatia's Pannonian Basin share the same basic engineering: paired wells circulating hot water through a closed loop.

2020s

Szeged, Hungary (2020s)

Hungary's second city built one of Europe's largest geothermal district heating projects with EU backing, using wells in the same Pannonian Basin that holds Croatia's resources.

Then

Szeged expanded geothermal supply across multiple phases of its district network.

Now

It showed that Pannonian Basin geology can sustain commercial-scale municipal heating.

Why this matters now

Hungary's success in the same basin underpins expectations that Croatia's wells will perform; it is the regional precedent closest to home.