Croatia reconnects Zabok–Lučko and Kozarac–Sisak pipelines after coordinated four-day shutdown

Croatia’s gas transmission network has taken a step toward greater resilience after two major pipeline sections were successfully integrated following a carefully managed four-day outage. The reconnection of the newly built Zabok–Lučko and Kozarac–Sisak lines matters for system flexibility because it strengthens how gas can be routed across key parts of the national grid—while demonstrating the ability to execute complex tie-ins without extending service disruption.

Two pipeline sections brought into the national grid

The Zabok–Lučko section was connected at the Lučko gas hub, while the Kozarac–Sisak line was tied into the existing Zagreb East–Kutina pipeline near the Kozarac node. Croatia’s system operator Plinacro oversaw the operation, with works carried out by Monter and other contractors. All activities were finalized within the planned 96-hour interruption window.

Shutdown procedures used nitrogen before recommissioning

During the shutdown, extensive safety and environmental procedures were implemented. Natural gas was first evacuated from the system in accordance with strict methane emission regulations, after which nitrogen was introduced to create safe working conditions. Once connections were completed, the system was gradually recommissioned: nitrogen was replaced by natural gas and pressure was restored to normal operating levels.

Coordinated work limited additional interruptions

Carrying out tie-in works simultaneously at two separate locations required complex coordination, but it also helped avoid additional service interruptions. During maintenance, gas inflows from the LNG terminal on Krk were temporarily halted, while the southern part of the network depended entirely on domestic production from the northern Adriatic. Nearly 90 kilometers of pipeline were isolated from service during the period.

Despite the scale and operational complexity, the project concluded without unexpected disruptions, reinforcing Croatia’s ability to integrate new infrastructure while maintaining continuity through planned network adjustments.