Allseas lays 20-kilometer pipeline for EU’s first large-scale CO2 transport and storage project

July 23, 2025, by Nadja Skopljak

Allseas’ Lorelay has completed offshore pipelaying for the Port of Rotterdam CO2 Transport Hub and Offshore Storage (Porthos) project, the first offshore carbon capture and storage (CCS) project in the Netherlands.

This first large-scale CO2 transport and storage project to be realized in the EU is designed to transport CO2 captured from industry through the Port of Rotterdam to depleted gas fields in the North Sea, approximately 20 kilometers off the coast, where it will be permanently stored at a depth of more than 3 kilometers beneath the seabed.

Allseas is the main offshore contractor, in charge of the installation, burial and commissioning of the 20-kilometer pipeline, connecting the future compressor station, located at the Maasvlakte, with the TAQA-owned P18-A platform offshore. The offshore pipeline is provided with a plastic insulation coating to retain the heat in the pipe and a concrete weight coating for stability on the seabed.

The company’s purpose-built offshore construction vessel (OCV) Oceanic was in charge of a special unexploded ordnance (UXO) survey along the pipeline route, after which Lorelay started installing the 16-inch pipeline.

Due to a technical issue with onboard tensioning equipment, the pipelaying vessel paused the work on May 7 to go to port for inspection, repair, and full system testing. After all systems were cleared and put into operation, pipeline installation restarted on July 11.

With the pipe now laid, trenching is on schedule, where the pipeline will be buried to ensure long-term protection and reliability.

The final investment decision (FID) for Porthos was reached in October 2023.

MAN Energy Solutions is to deliver three integrally geared compressor trains, and KCI is in charge of engineering the modification of the P18-A platform, transforming the facility into a platform for permanent offshore CO2 storage. Expro will supply tubular running services (TRS).

Developed by a joint venture of EBN, Gasunie, and the Port of Rotterdam Authority, Porthos is expected to enable the Rotterdam port industry to emit about 10% less CO2 and contribute to CO2 reductions of around 17% for the industry in 2030.