The twin pipeline runs through a 510-kilometre stretch of the Swedish EEZ. Several sections will require preparation prior to pipelaying.
Before construction can start, some preparatory activities need to be carried out. Planned for the third quarter of 2018, these include rock placement and the installation of concrete mattresses. Rock material needs to be placed at precisely defined locations along the route to support the pipeline where the seabed is uneven, for example. Concrete mattresses will be installed to protect existing infrastructure such as power and telecommunications cables, in addition to existing pipelines.
Pipelaying in the Swedish EEZ will be performed with a dynamically-positioned pipelay vessel. Some rock placement and trenching will also be required once the pipelines have been laid on the seabed. A plough will be used to entrench approximately 20 kilometres per pipeline into the seabed along three sections of the southern part of the Swedish route.
During rock placement and mattress installation, safety zones of 500 metres will be required around the construction areas, resulting in temporary navigational restrictions. The safety zone around the pipelay vessel will be one nautical mile (1.85 kilometres). All safety measures within the Swedish EEZ have been set up in cooperation with the competent authorities, including the Swedish Maritime Administration. The responsible national authorities will oversee preparatory and construction activities and ensure that they are carried out according to the permit’s provisions. Nord Stream 2’s contractors will report on their planned and executed activities to the authorities on a regular basis. Independent contractors will monitor the potential environmental impacts of the construction activities in accordance with the environmental monitoring programme set up together with the competent authorities, including the Swedish Environmental Protection Agency.