Allseas setting the stage for pipelaying at EU’s landmark CO2 transport and storage project

An Allseas vessel has commenced offshore works for the first offshore carbon capture and storage (CCS) project in the Netherlands with an unexploded ordnance (UXO) survey along the pipeline route, seen as one of several important pre-lay activities before pipeline installation.

Allseas’ purpose-built offshore construction vessel (OCV) Oceanic has been put to work for a special UXO survey along the 20-kilometer pipeline route for the Porthos (Port of Rotterdam CO2 Transport Hub and Offshore Storage) project, after which the pipelay vessel Lorelay will install the 16-inch pipeline.

According to the company, it is fortunate that the hi-tech imaging and sonar spread, capable of visualising objects up to four metres below the seabed, detected no explosives.

Porthos, the first large-scale CO2 transport and storage project to be realised 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.

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

Allseas is the main offshore contractor for Porthos, in charge of the installation, burial and commissioning of the 16-inch 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.

Lorelay will commence pipelay in late April with a pull-in to the compressor station, before setting off in the direction of the P18-A platform, while Oceanic will provide construction support.

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.

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.