Precision Operation

In January 2025, AF Offshore Decom signed a contract with Allseas for the disposal of TAQA UK’s Eider Alpha platform topside. The structure was lifted in a single operation by Allseas’ heavy-lift vessel, Pioneering Spirit, before being transported to the AF Environmental Base in Vats, Norway, for dismantling and disposal. On the weekend of 18-19 October 2025, Pioneering Spirit arrived in Vatsfjorden where the topside was transferred to Allseas’ purpose-built cargo barge, Iron Lady, and subsequently skidded onto the quay at the AF Environmental Base. The topside will be processed for dismantling and recycling, with a target of at least 97% materials recovery.

“Projects like the removal of TAQA UK’s Eider Alpha platform highlight the strength of our single-lift removal technology, while AF’s expertise ensures the topsides are safely and responsibly recycled – reflecting our shared commitment to sustainable North Sea decommissioning,” says Jeroen van der Sman, Project Manager at Allseas.

“This was our first operation for Allseas, and the collaboration has been excellent throughout the entire process,” says Sigrid Ramuz Bomann-Larsen, Project Director at AF Offshore Decom.

Christer Korsvold, Project Manager at the AF Environmental Base in Vats, led the engineering and fabrication of the bespoke load-in system for the quay.

“Although the base has previously received larger structures, such as the FPSO Curlew, this is the first time a platform topside of this scale has been loaded in a single operation,” says Sigrid.

Once the design was finalised, the system was fabricated and assembled into a complete load-in arrangement. Material selection and load distribution were carefully engineered to ensure optimal performance.

“The challenge was that the platform is designed to stand upright, with significant weight concentrated over a relatively small footprint. Any unevenness in the load-in system could have caused structural failure. We had to work within extremely tight tolerances,” says Elias Lillebostad, Engineering Manager at AF Offshore Decom.

The load-in system consisted of a 200-metre-long, custom-built skid track, levelled with millimetre precision. Across a 10-metre span, the maximum allowable height deviation was ±5 mm.

The operation was meticulously planned using digital models and site-specific survey requirements, followed by physical verification on location.

“The operations team at the AF Environmental Base in Vats contributed invaluable experience from previous projects. Their input on practical execution was crucial,” says Lillebostad, who developed the solution together with Tommy Wang and Eivind Reppen. Several newly graduated and recently hired engineers also participated to gain hands-on experience.

Due to the platform’s weight, load distribution was a critical factor. Norconsult was engaged to verify calculations and assess the structural impact on the quay.

“The quay piles are inherently strong, and we wanted to leverage that. By designing a tailored load distribution system, we were able to optimise force dispersion,” says Lillebostad.

TAQA UK’s Eider Alpha platform was in production from 1988 to 2018 and most recently served as a utility platform supporting TAQA UK’s North Cormorant platform in the UK sector of the North Sea. Following the removal of Eider’s topside, it will now be safely dismantled, and sorted for, recovery, recycling and disposal.

AF Offshore Decom sends the recovered metal to a recycling partner whose process emits 85% less CO₂ than conventional ore-based production due to the use of hydropower as a cleaner energy source for the electric arc furnace. This equates to a reduction of 1.9 tonnes of CO₂ per tonne of recycled metal, which is used in products such as reinforcement steel for new buildings. Marine growth will be composted and turned into topsoil, while hazardous waste is safely treated and disposed of in line with regulations, site permits, and industry best practice.