Croatia’s Rijeka oil refinery has entered the final stage of a large-scale modernization, with construction of the main facilities now complete and extensive testing underway ahead of a planned launch in the first quarter of 2026. The upgrade includes the completion of the heavy residue processing unit and supporting infrastructure, such as a newly built port area, all undergoing comprehensive technical and safety checks before the refinery can receive its operating permit and transition to full commercial operation.
With a total investment approaching €700 million, this project is the largest single investment in INA’s history. More than half of the construction was carried out by domestic contractors, highlighting its importance for both the local industrial sector and the national energy system.
Beyond the heavy residue processing unit, the modernization included upgrades to existing refinery units, construction of new silos, a closed coke transport system, and a high-capacity substation—the largest of its kind in Croatia—designed to supply electricity to the newly built facilities. According to INA, these upgrades form a comprehensive technological transformation, positioning Rijeka as one of the most advanced refinery complexes in the region. The current testing phase involves system trials and safety verifications to ensure that all installations meet regulatory and operational standards before production ramps up.
The project was carried out while the refinery continued uninterrupted operations, marking its longest continuous operating period in 15 years. During this period, record processing volumes were achieved, domestic supply was maintained, and conditions were created for stronger long-term energy security.
Once the heavy residue processing unit becomes operational, INA expects diesel output to increase by up to 30%, alongside higher production of other high-value petroleum products. This expansion will strengthen Croatia’s fuel balance and improve the profitability of INA’s refining business.
INA plans to prioritize stable supply for Croatia and neighboring markets, including Bosnia and Herzegovina, Montenegro, and Slovenia. The upgraded refinery is expected to significantly reduce fuel imports, particularly diesel, which is critical during peak demand in the tourist season. Another strategic advantage is the elimination of vacuum gas oil imports, previously sourced mainly from Russia, allowing the refinery to rely more on its own processing capabilities, increasing resilience and reducing exposure to external supply risks.
