Home : Case Studies : Vattenfall Europe Transmission GmbH / Primo Marine BV

Vattenfall Europe Transmission GmbH / Primo Marine BV

Pipeline Crossing Design

Pipeline - Cable Crossing

Project Overview ´╗┐

This conceptual design / feasibility study focused on the marine crossing of AC power cables with a dual gas pipeline system in the Baltic Sea near the German Coast. A planned total of sixteen [16] AC cable systems will cross (or be crossed by) two large diameter gas pipelines in the vicinity of the mouth of the Greifswalder Bodder, close to the German coast.

Two [2] crossing locations were identified by the Client and the study assumed that eight [8] cables were to be installed at each of these crossing locations.

Two [2] separate installation sequences were studied, the first involving some of the cables being installed before the pipelines and the second involving all cables being installed after the pipelines.

The most significant feature of the crossing design was the combined effects of the large physical pipeline size [approximately 1.5m outer diameter], the relatively shallow water depth at the crossing locations [between 8 and 14m water depth], and the requirement of both the Client and the pipeline company to have 1.5m cover to the top of their respective cables and pipelines.

The combined effect resulted in a crossing design which is not considered to be conventional.

The Client used the final report as support for their crossing agreement discussions with the pipeline company.

imgnews

Scope of Services

Consub acted as a subcontractor to Primo-Marine BV in the performance of the conceptual design / feasibility study.

A total of six [6] separate designs were evaluated, three [3] for the scenario where some of the cables are being installed before the pipelines and three [3] for the scenario where all cables are being installed after the pipelines.

The evaluation  considered technical feasibility, environmental impact, the high-level risks and the cost impact associated with each of the crossing designs.