The pipeline has been laid in sections between the two landfalls at an ambitious rate. Orchestrating this process has involved a fleet of state-of-the-art vessels supported by a tightly managed logistics plan and extensive survey works.
Varying seabed topography required preparatory works before pipelaying could begin. This included rock placement at dedicated locations along the route to support the pipeline where the seabed is uneven, for example. In the shallow waters near the Russian and German landfalls, dredging and backfilling were used to bury the pipeline in the seabed to stabilise it against water and sand movements. Crossing installations were also placed where the pipeline intersects with existing infrastructure such as telecommunications and power cables, or other gas pipelines.
Because the Baltic Sea was used as a dumping ground for munitions after the World Wars, the route was optimised to avoid unexploded ordnance (UXO) wherever possible. This prevented any impact to construction, operation or valuable cultural heritage. Munitions still found in the route corridor were cleared using extensive mitigation methods to minimise environmental impacts, though use of dynamically positioned pipelay vessels that don’t employ anchors reduced the need for clearance in many cases.
Exclusion zones were also established around cultural heritage objects for their protection during construction.
Installation of the pipeline was carried out by multiple high-tech vessels working around-the-clock along various route sections. Pipe deliveries from strategically located logistics hubs supported these floating factories, where pipes were welded together and installed on the seabed at a rate of up to 3 kilometres per day.
Following pipelay, surveys have determined where additional support, stabilisation or protection is needed with post-lay rock placement and ploughing. Now that the pipeline is complete, it will undergo further testing and be independently verified and certified before commissioning.
