Energean and INA greenlight €71m Irena gas field project in Croatia with first gas by 2027

How will the Irena gas field tie-back project strengthen domestic gas supply in the Adriatic region?

Energean plc (LSE: ENOG, TASE: ENOG) and its joint venture partner INA – Industrija Nafte d.d. have formally approved the Final Investment Decision (FID) for the development of the Irena gas field, located offshore Croatia. The shallow-water field will be developed via a single platform tie-back to existing infrastructure at the nearby Izabela field, with first gas expected in the first half of 2027.

This €71 million project marks a notable strategic step for both Energean and INA as they seek to expand upstream gas production in the northern Adriatic basin. Energean holds a 70% working interest in the Irena development and will contribute approximately €50 million of the total capex. The remaining 30% is held by INA, Croatia’s national oil and gas company.

The Irena field is part of the Izabela concession, operated by Edina d.o.o., a 50:50 joint venture entity co-owned by Energean and INA. According to the companies, the project’s P50 gas reserves stand at 30.5 billion cubic feet (Bcf) gross, equivalent to 5.4 million barrels of oil equivalent (mmboe). The development will target gross peak production of 8 to 10 million standard cubic feet per day (mmscfd), or approximately 1,400–1,700 barrels of oil equivalent per day (boe/d).

What does this project signal about the future of energy security in Croatia and regional gas independence?

This FID follows a string of regional upstream investments designed to mitigate Europe’s energy supply risk in the aftermath of geopolitical disruptions, including the reduced flow of Russian gas since early 2022. Croatian officials have increasingly prioritized domestic resource development as a pillar of long-term energy policy.

Josip Bubnić, operating director for exploration and production at INA, framed the decision as a crucial step in supporting Croatia’s energy sovereignty. He noted that the Irena project was aligned with INA’s broader strategy of reinforcing domestic oil and gas production while preserving Croatia’s regional leadership in upstream operations.

For Energean, the Irena project also aligns with its broader Mediterranean gas portfolio strategy, which has included expansions in Israel, Egypt, and now Croatia. Francesco Federici, country manager for Energean in Croatia, characterized the investment as both strategic and collaborative, highlighting the long-standing joint venture with INA as a key success factor.

The gas from Irena will be sold under a long-term Gas Sales Agreement between Energean and INA, ensuring predictable offtake and revenue generation once production begins. The project’s technical profile—a tie-back to existing facilities in 45-meter water depth—also reduces development risk and capex intensity compared to greenfield projects.

Why are shallow-water tie-backs gaining investor interest in Europe’s smaller gas basins?

Analysts note that smaller-scale, shallow-water tie-back projects like Irena are becoming more attractive in regions where infrastructure already exists, particularly in the Adriatic and North Sea. These developments provide quicker paybacks, lower breakeven costs, and lower ESG risks than deepwater or unconventional alternatives.

From an institutional sentiment perspective, investors have viewed Energean’s recent portfolio moves—especially those focused on gas monetization in proximity to European markets—as consistent with energy security themes that remain top-of-mind in 2025. Several equity analysts covering Energean have previously pointed to Croatian developments as “low-risk and infrastructure-advantaged,” although specific investment firm names were not disclosed in the release.

Moreover, the decision to proceed with the Irena development amid an era of increasingly stringent ESG scrutiny underscores the shifting definition of energy transition investments. While not a renewable project, Irena’s gas production is framed by both companies as a cleaner-burning bridge fuel that supports grid stability and domestic industrial demand.

What are the financial and production expectations for the Irena gas field over the medium term?

With an estimated peak output of up to 10 mmscfd gross, Irena will be a modest contributor to Croatia’s national gas supply but a strategically important one. The entire output will be processed via existing infrastructure at the Izabela field, further reinforcing the cost-effective nature of the tie-back model.

Energean’s net entitlement gas will be marketed under its long-term agreement with INA, locking in offtake well ahead of production. This setup allows Energean to de-risk revenue streams and preserve its capital-light business model in the region. The field’s economics benefit further from minimal offshore logistical complexity due to its shallow-water location and established subsea connections.

INA, for its part, continues to deepen its upstream investments after years of limited domestic project announcements. The Irena greenlight complements other initiatives aimed at halting Croatia’s rising reliance on imported LNG, especially in light of terminal constraints and the need to secure baseload fuel for industry and heating.

How does the Irena development fit into Energean’s and INA’s broader regional strategies?

For Energean, which has pursued an ambitious strategy of Mediterranean gas monetization, the Irena FID reinforces its image as a disciplined operator capable of unlocking value from secondary fields and legacy infrastructure. The company’s strategy continues to blend high-impact exploration in the eastern Mediterranean with tactical monetization of smaller fields like Katakolo in Greece and now Irena in Croatia.

Meanwhile, INA appears to be doubling down on Adriatic resource development. The Irena approval adds momentum to INA’s stated goal of energy independence and regional supply leadership, though questions remain around the pace of domestic permitting and licensing.

At the macro level, this development reflects a growing shift in southern and eastern Europe’s energy strategy—one where national governments, under increasing pressure to secure reliable and affordable fuel sources, are turning to pragmatic partnerships with private and semi-public operators to unlock domestic gas potential. Rather than relying solely on costly LNG import infrastructure or banking on long-horizon hydrogen initiatives that remain commercially untested, countries like Croatia are prioritizing fast-cycle, infrastructure-linked gas projects that offer measurable security-of-supply benefits.

The Irena gas field, with its modest capex, shallow-water setting, and tie-back design, fits squarely within this evolving framework. By advancing Irena, Energean and INA are embracing a practical, low-risk approach to energy development that aligns with both near-term supply imperatives and mid-term transition goals. The strategy underscores a broader European trend toward “energy resilience through infrastructure reuse”—where speed, existing networks, and regional collaboration increasingly outweigh speculative bets on emerging technologies.