Bulgaria to lift Vertical Corridor transit capacity from July as Romanian gas eyes 5bcm

Bulgaria to lift Vertical Corridor transit capacity from July as Romanian gas eyes 5bcm Sofia's capacity expansion and looser quality rules open a southern route for non-Russian gas, but Balkan-Ukraine auctions are still drawing zero bids. Bulgaria will begin raising gas transit capacity on the Vertical Corridor from July, the route that carries non-Russian gas north from Greek LNG terminals through Bulgaria and Romania toward Ukraine. Traders told Montel that Bulgaria could import at least 5bcm of gas from Romania next year once Transgaz lifts capacity to 5bcm, with Sofia treating that supply as a priority¹. The Balkans have spent three years trying to engineer a way around Russian pipeline gas, and a working southern route is the physical proof it can be done. Romania's domestic production already covers more than 90% of its own consumption, which leaves spare network space to move volumes onward rather than just backfill at home³. The capacity build is being paired with a rule change that gets less attention but may matter more. Bulgaria and Romania are both relaxing the gas-quality specifications for molecules entering their transmission systems, a step traders said would make it easier to push regasified LNG through the Vertical Corridor². Cargoes landed at Greek terminals carry different calorific and composition profiles than pipeline gas, and tight specs have historically blocked them at the border². Romania is the supply story underneath the transit story. The country's 100bcm Neptune Deep project in the Black Sea, plus joint exploration, would strengthen regional output and give the corridor something to carry, the same traders said¹. Neptune Deep is years from full ramp, so the near-term 5bcm figure leans on existing Romanian production and redirected flows rather than new gas¹. The bullish read is straightforward. More capacity, looser specs, and rising Romanian volumes should deepen liquidity on a route that barely existed as a commercial artery two years ago¹. Greece becomes the entry point for LNG, Bulgaria the transit spine, and Ukraine the demand sink². Yet the demand signal does not match the infrastructure optimism. The most recent monthly auction for gas from the Balkans to Ukraine drew no bids on the RBP platform on Wednesday (2026-04-22), with the Ukrainian and partner TSOs failing to sell capacity that earlier months had cleared⁴. Traders blamed volatility in regional gas prices tied to the conflict, which made committing to forward transit unattractive⁴. Those auctions are the cleanest live read on whether the corridor is being used, not just built. The TSOs offered 23.7 GWh/day for May delivery on Route 1 and 36.9 GWh/day on both Route 2 and Route 3, and none of it moved⁴. Capacity on paper is not the same as gas in the pipe. There is also a limit worth naming. Romania aside, most Balkan states produce little of their own gas and depend on imports, so the corridor's value rests on cargoes arriving at Greek terminals and on Romanian volumes actually being released for export rather than held at home³. Watch three things from July. First, whether Transgaz confirms the capacity steps on schedule and at what tariff¹. Second, whether the next Balkan-Ukraine auctions clear or draw another round of zero bids⁴. Third, whether the relaxed quality rules translate into measurable LNG send-out through Greece, the test of whether specs were the binding constraint all along².