The Vertical Gas Corridor is being developed from a short-term response to disrupted Russian supplies into a broader infrastructure and market-integration project linking southern Europe with Ukraine and central European gas hubs. Transmission system operators from nine countries are now involved in the initiative. Greece, Bulgaria, Romania, Moldova and Ukraine have been joined by Serbia, North Macedonia, Hungary and Slovakia.
At a meeting in Athens, the operators agreed to set up a working group focused on the technical, regulatory and operational requirements for integrating the Serbian and North Macedonian networks. The work is aimed at more than reserving cross-border capacity. It also covers alignment of operating rules, nomination procedures, tariffs and gas-quality standards across systems built around different supply routes.
From LNG-linked routing to broader market integration
The corridor was initially promoted as an alternative route for transporting gas northwards from Greek LNG terminals after Russian transit through Ukraine was reduced. It is now being positioned as a permanent part of southeast Europe’s gas architecture. The project is described as providing access to LNG, Azeri gas and potentially other non-Russian supplies.
Greece has become the principal southern entry point for the corridor. Its export capacity increased from approximately 1 billion cubic metres in 2021 to around 9 billion cubic metres. The expansion is supported by LNG infrastructure and improvements to neighbouring transmission systems.
Additional capacity is expected when the Greece–North Macedonia interconnector enters operation, currently scheduled for the end of 2027. This timing links the next phase of southern entry capability with network integration plans in the western Balkans.
Western Balkan participation and cross-border operating alignment
Serbia’s involvement is intended to strengthen the corridor’s western Balkan dimension. Serbia is described as occupying a central position between Bulgaria, Hungary and former Yugoslav markets. However, its gas system has historically been oriented towards Russian supply delivered via the Balkan Stream route.
Connecting Serbia more effectively with Greece would provide additional supply optionality. The source notes that any commercial benefit will depend on competitive transmission tariffs and firm capacity availability across multiple borders.
Timeline for capacity products and formal incorporation
The next practical milestone is an auction of three-month transmission products in August 2026. Following that auction, the nine operators are expected to sign a memorandum in September to formally incorporate Serbia and North Macedonia into the initiative.
The corridor’s growing relevance is linked to European Union efforts to end remaining Russian gas imports by autumn 2027. Poland and Slovakia have also expressed interest in closer participation through the Central and South Eastern Europe Energy Connectivity framework.
Infrastructure development alone is not presented as sufficient for commercially viable flows. The route crosses multiple tariff zones, and accumulated transmission charges can make LNG delivered through Greece more expensive than alternatives arriving from central Europe. Long-term value is therefore described as depending on coordinated capacity products, tariff reform and enough contracted demand to support continuous rather than occasional gas movements.
