The final testing of the VGGT-1 exploratory geothermal well in Velika Gorica has confirmed a reservoir exceeding 100°C—potentially transforming the city’s central heating landscape.
According to Croatia’s Hydrocarbon Agency, energy from the well could cover approximately 60% of Velika Gorica’s district heating needs, contingent on the construction of an additional reinjection well to secure long-term operational stability.
This development positions Velika Gorica as a strategic case study in Croatia’s evolving geothermal strategy. Unlike intermittent renewables like solar and wind, geothermal heat provides baseload thermal energy with minimal exposure to external market or meteorological volatility. The VGGT-1 site, operated by CROSCO (a subsidiary of the INA Group), presents a rare confluence of high-enough subsurface temperatures and proximity to an urban center, making it a cost-efficient alternative to fossil-based heat.
Investment in this single well has already surpassed €11 million, drawing from Croatia’s National Recovery and Resilience Plan (NPOO). Within that broader framework, €50.8 million has been allocated to upgrade heating systems and promote renewable thermal solutions nationwide. Yet despite its promise, Velika Gorica’s project will only succeed if supported by system-level changes—including thermal grid upgrades and strong reinjection infrastructure to preserve reservoir pressure and heat sustainability over time.
The Agency’s claim that the geothermal source could meet 60% of demand lacks publicly disclosed modeling details, but aligns with baseline calculations from comparable low-enthalpy European projects. Cities like Munich and Paris, for example, have already tapped into geothermal aquifers ranging from 80°C to 110°C, covering between 20% and 70% of urban heat loads under similar district heating conditions.
The potential extends beyond urban heating. The project could open new fronts in agricultural applications—particularly greenhouse heating—where stable low-cost heat enhances crop productivity and reduces dependence on volatile energy inputs. However, such diversification requires additional infrastructure planning, including secondary heat distribution networks and clear governance for resource allocation.
Speaking for the Hydrocarbon Agency, President Marijan Krpan emphasized the significance of geothermal energy as a “practically applicable” local resource with national relevance. His remarks highlight a strategic pivot in Croatia’s energy planning: leveraging endogenous renewable resources not merely for grid decarbonization, but also for regional economic resilience.
Ongoing exploration activities in other cities—including Osijek, Vinkovci, and Zaprešić—are part of a broader campaign to map and quantify Croatia’s geothermal potential. Still, with most domestic heating systems historically built around natural gas or fuel oil, the transition to geothermal will require addressing legacy infrastructure limitations and regulatory inertia.
If Velika Gorica becomes a proof of concept, it could reframe how mid-sized European cities approach thermal decarbonization—grounding climate targets in accessible subsurface energy instead of long-distance grid dependence. The challenge will be to move from exploratory promise to systemic integration, ensuring that resource abundance translates into public benefit without sacrificing environmental safeguards or long-term reservoir health.
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