Two of the three discussed Vertical Gas Corridor routes position the IGB pipeline as core infrastructure, offering direct access to TAP and future LNG supplies from Alexandroupolis

More than 34.5 million MWh of natural gas have been transported through the Greece–Bulgaria interconnector (IGB pipeline) since the start of its commercial operations at the end of 2022. Operated by ICGB, the pipeline continues to play a vital role in strengthening energy security and diversification in Bulgaria and the broader region, with over 45 registered network users and stable market interest.

The interconnector currently supplies over 40% of Bulgaria’s domestic consumption during winter months, and more than 60% during summer, while also enabling virtual reverse flow deliveries to Greece.

Since the start of operations, approximately 2 million MWh have been transported in the reverse direction, showcasing the interconnector’s operational flexibility. ICGB is fully prepared to offer commercial reverse flow from Bulgaria to Greece at the Komotini interconnection point (IP ICGB-DESFA) as soon as the corresponding entry capacity becomes available on the Greek side. Close cooperation with the Greek transmission system operator is ongoing to enable this opportunity and further enhance regional gas market flexibility. ICGB operates two key gas metering stations – one double in Komotini in the interconnection points with TAP and DESFA and one in Stara Zagora in the interconnection point with Bulgatransgaz - and serves as the trusted party responsible for measuring gas flows on behalf of the adjacent transmission system operators.

Beyond these volumes, ICGB serves as a strategic partner and driving force within the Vertical Gas Corridor (VGC) - a key European initiative aimed at enabling diversified, non-Russian gas flows across Central and Southeastern Europe. Since 2016, ICGB has been at the heart of this vision, offering a modern, EU-supported interconnection between Greece and Bulgaria that enables access to supplies from the Caspian region via the Southern Gas Corridor. The IGB pipeline is directly connected to the Trans Adriatic Pipeline (TAP), is strategically located near the Alexandroupolis FSRU, and physically links the Southern and Vertical Gas Corridors. Its significance for both national and regional energy systems will be amplified by an expansion to 5 bcm/y, unlocking greater supply volumes and boosting reverse flow capabilities across EU member states and partners.

“The IGB pipeline is a strategic European asset,” said Teodora Georgieva, Executive Officer at ICGB. “As one of the original supporters of the Vertical Gas Corridor, we remain firmly committed to its founding objectives: long-term diversification, flexibility, and energy solidarity.” According to her, in late 2022, just weeks after the launch of commercial operations, ICGB became the first regional transmission operator to enable reverse flows through the Trans-Balkan pipeline, successfully delivering gas to Moldova and Ukraine at a time of need. This marked a turning point for regional coordination and underscored IGB’s critical role in supporting vulnerable energy systems.

“Supporting Ukraine and Moldova’s access to secure, diversified energy remains a core priority,” added George Satlas, Executive Officer at ICGB. “We’ve consistently advocated for the inclusion of their transmission system operators in the Vertical Gas Corridor and stand ready to contribute further with smart, EU-compliant solutions.”

As the Vertical Gas Corridor continues to evolve as a strategic European initiative, it is important to recognize the availability of three discussed route configurations. 2 out of the 3 involve the IGB pipeline as core infrastructure, bringing strategic benefits - direct access to the Southern Gas Corridor via TAP and respectively to LNG supplies from the Alexandroupolis terminal once fully operational. These routes offer strong potential for enhancing long-term energy security and regional supply flexibility.