Construction of Slovenia’s new M6 DN400 gas pipeline between Ajdovščina and Sežana has been completed ahead of schedule, marking a key milestone in the modernization of the country’s gas transmission infrastructure.
The project was carried out in one of the most technically challenging regions in southwestern Slovenia, where construction teams had to operate across steep terrain and difficult geological conditions.
Following the completion of construction works, the pipeline has successfully undergone pressure testing and drying procedures, and is now fully prepared for commissioning and initial gas injection.
A key long-term feature of the infrastructure is its readiness for hydrogen transport. Once the required certifications and regulatory approvals are obtained, the pipeline will be capable of transporting pure hydrogen, aligning the project with Slovenia’s broader energy transition strategy.
The construction process included several complex engineering operations, including calibration works along pipeline sections, pressure testing over a continuous 8.5-kilometer stretch, and installation works on slopes reaching inclinations of up to 65 degrees, where cable transport systems were used.
In addition, crews completed the laying of a 500-meter section on terrain with a steep 45-degree gradient, highlighting the demanding nature of the project environment.
The challenging conditions underscored the technical expertise of the local contractor Monter, which carried out the installation works. The company relied on specialized engineering solutions to complete the project safely and ahead of schedule despite the difficult terrain and operational constraints.
