The pipeline will - depending on the route that will be built – stretch between 147 and 175 kilometers through Danish waters. Construction activities will include pipe laying and seabed intervention works.
The installation is expected to be sequential, with one pipeline installed at a time. The individual pipe joints will be delivered to the pipelay vessel, where they will be assembled into a continuous pipeline and lowered to the seabed.
Both pipelines will be constructed in specific sections for subsequent interconnection. This may include abandonment and recovery operations, which involve leaving the pipeline along its route and retrieving it later if weather conditions make positioning difficult or cause too much movement within the system. The average lay rate is expected to be around 3 kilometers per day, depending on weather conditions, water depth and pipe wall thickness.
The offshore installation of the pipelines in some areas requires additional stabilization and/or protection against hydrodynamic loading, which can be achieved by either trenching the pipeline into the seabed or using rock placement.
A maximum of 4 kilometers of post-lay trenching is anticipated for each of the pipelines if the south-eastern route is built, and of 14.5 kilometers if the north-western route is built.
The proposed Nord Stream 2 routes cross existing power and communication cables as well as the existing Nord Stream twin pipeline in Danish waters. The north-western route crosses six active cables, while the south-eastern route crosses two active cables. Rock placement will be carried out where the new pipeline crosses the existing Nord Stream pipeline to provide support for separation between the two systems. As with the successfully completed Nord Stream project, the plan is to develop solutions for each cable crossing. These will typically consist of concrete mattresses that are agreed upon by the cable owners. The crossing with the Nord Stream pipeline will be designed according to normal industry practice.