The Vertical Gas Corridor is approaching a commercial test in 2026/27, when utilisation and northbound flows will show whether gas entering Southeast Europe from the south can become a regular, cost-effective supply route. The outcome will depend on whether capacity can be booked and used under competitive, workable cross-border terms.
Gas from LNG terminals or pipelines in Greece is envisaged to move north through Bulgaria and Romania, then toward Moldova, Ukraine, Hungary and the Western Balkans. Serbia and North Macedonia joining the corridor broadens its addressable market, while new interconnectors can add demand for gas arriving from Greece.
A strategic route does not by itself create a functioning trading corridor. Commercial users need available capacity products, harmonised balancing rules and predictable tariffs, as well as price spreads between origin and destination markets wide enough to cover transport costs. The Energy Community has pushed common gas rules across EU and Energy Community jurisdictions and stressed the need to turn existing infrastructure into functioning supply routes.
Traders will assess performance through booked capacity, actual flows and tariff changes, including whether gas moves against historical direction, rather than through infrastructure inaugurations. Persistent south-to-north flows would indicate that Southeast Europe is developing into a functioning gas market instead of remaining a collection of emergency diversification projects. Sustained use, competitive tariffs and reliable capacity products will determine whether the route lowers procurement costs.
Q1 2027 should provide a clearer indication of whether southern supplies can displace higher-cost alternatives during winter peaks, after Q4 2026 tests rule harmonisation and utilisation. Congestion or incompatible network rules could maintain local price premiums despite available technical pipeline capacity; if capacity is physically available but commercially constrained, regional basis premiums could widen sharply.
