Traders Back Greek Gas Route

The July gas auctions in south-eastern Europe produced something Brussels energy policy often lacks: a market signal backed by actual money. Traders booked around 46% of available export capacity at Sidirokastro, the main Greece-Bulgaria gas crossing, with some reservations running as far as 2040/41 (Serbia Energy, News247).

That matters because Sidirokastro is one of the gates into the Vertical Gas Corridor, the chain of pipelines meant to carry liquefied natural gas from Greek import terminals up through the Balkans and into Central Europe. For the first time, the route has produced a serious commercial commitment. Whether it can make sense all the way across the map is the harder question.

Every border is a toll booth

The corridor sounds simpler than it is. LNG tankers arrive at Revithoussa, near Athens, or at Alexandroupolis in northern Greece. The cargo is turned back into gas and fed into the Greek network. From there it crosses into Bulgaria through two border points, then moves on through Romanian pipelines, in part reversing infrastructure that once brought Russian gas south, towards Hungary, Slovakia, Moldova and Ukraine (Powergame, DW România).

Europe's gas system is not a motorway where a shipper pays once and keeps driving. At each national border, traders have to reserve entry and exit capacity, pay the transmission tariff, and comply with balancing rules, meaning the daily requirement to match gas entering the system with gas leaving it. The route works only if capacity is lined up across every section. Miss one border, and the chain breaks.

The July bookings happened because tariffs came down. After cuts on the Romanian leg, the cost of moving gas from Greece to Ukraine fell from €9.39 per megawatt-hour to roughly €5.85 (Euro2day). That was enough to bring traders into the auction.

Greek terminals are filling up

The Greek end of the system is already busier. In the first half of 2026, Revithoussa processed 18.61 TWh of gas, while Alexandroupolis handled 3.46 TWh, more than three times its volume a year earlier (Iefimerida). At the latest Alexandroupolis capacity auction, all available capacity was sold, with buyers paying above the reserve price because access was limited (BankingNews).

Greece gets transit fees, terminal income and a stronger hand in regional supply politics. Bulgaria gets another route around its awkward fixed-fee arrangement with Turkey's Botaş for LNG access, a contract whose critics said only 10-20% of the capacity was actually being used (Fakti).

The competition the corridor has to beat

Romania sits in the middle of the corridor, which makes it both indispensable and potentially inconvenient. It carries transit gas today. But its Neptun Deep field in the Black Sea, with estimated resources of around 100 billion cubic metres, could begin producing around 2027 (HotNews). If Romanian gas reaches Central European buyers at scale, some of them may have less need for LNG routed up from Greece.

Russian gas has not vanished from the system either. ACER, the EU agency for energy regulators, says it still accounted for about 12% of EU consumption in January-May 2026, with pipeline imports up 7% and LNG imports up 11% year on year (InvestEnergy). For countries such as Slovakia, where energy-intensive industry depends on affordable gas, the test is whether LNG arriving through Greece can beat the remaining Russian-linked contracts on price (Energie-portal).

The wider market is pushing in the same direction. The EU needs LNG imports roughly 13% above 2025 levels to refill storage to 90% before winter (Euronews). Moldova's state energy company, Energocom, has already booked capacity at the Romania-Moldova border, which shows the route is live for at least one small buyer (Moldova1).

The July auctions show traders will use the Vertical Gas Corridor when the price is right. It reduces dependence on a single supplier in a region that knows exactly what Russian leverage feels like. But there is still no public record showing capacity booked at the same time across every border from Greece to the final destination. In gas, as in politics, the route is only as reliable as the weakest crossing.