Romanian natural gas transmission system operator Transgaz has successfully completed the Danube River undercrossing, a critical section of the Tuzla-Podisor gas pipeline. The tunnel stretches 1,813 meters and reaches a maximum depth of 67 meters beneath the riverbed, making it one of Europe’s most ambitious horizontal directional drilling (HDD) projects.
During construction, engineers encountered unexpected geological challenges, including zones of dolomitization, which required on-the-spot adjustments to drilling methods. To handle the immense forces involved, the project employed two 400-ton HDD platforms—a pioneering approach at this level of complexity. This twin-rig setup allowed for better distribution of pulling and boring forces and improved operational control. An emergency pipe pusher mechanism was also in place to counteract excessive friction, ensuring the 40-inch pipeline could be installed without interruption.
Beyond its technical achievements, the undercrossing supports Romania’s goal to become a regional energy hub. Since the project’s launch less than three years ago, the Tuzla-Podisor pipeline route has attracted major investments. Approximately 500 million euros of its estimated cost are part of a broader 9.1 billion euro National Gas Transmission System development plan. Recognized as an EU Project of Common Interest, the initiative secured 85 million euros from the Modernization Fund, with the remaining funds to be obtained through competitive financing.
This milestone highlights Transgaz’s strategic commitment to advanced infrastructure and long-term energy security. Building on this success, the company plans further upgrades to the national transmission network, strengthening both domestic supply resilience and Romania’s role in the gas market of southeastern Europe.
