Culzean floating wind turbine reaches North Sea field after tow-out from Norway

The floating wind turbine built to power TotalEnergies' (now NEO NEXT+ Energy) Culzean gas platform in the UK Central North Sea has arrived on site, after being towed out from Wergeland Base in Gulen, Norway, late last week.

The unit left the industrial port near Mongstad on Friday, following roughly two years of engineering, fabrication and assembly work led by Archer Wind, the floating wind arm of Norwegian oilfield services group Archer. Once hooked up, the single Vestas 3 MW turbine is expected to supply around 20% of the Culzean platform's power needs, cutting emissions and reducing reliance on the gas turbines that currently run the facility.

"This is a huge project for us," said Charlotte Berge, executive vice president of renewables in Archer, speaking shortly before the tow-out. 

It's been a fantastic showcase for what Archer can deliver as an EPC contractor, but also for the expertise we already have in Norway from decades in the oil and gas industry — and how that translates into building new industry.

A bolted, not welded, foundation

The floater is built on a design from Ocergy, in which Archer Wind holds a minority stake. Unlike most floating substructures, which are welded together, the Culzean unit is assembled from prefabricated sections bolted together using large compact flanges — what the project partners say is the world's first bolted floating wind structure.

"From the outside it looks like a single welded pipe, but it's actually been built up from large, mirrored flange connections, with the nut and bolt on the inside of the pipe," explained Kolbjørn Kirkebo, the product manager of the Archer Wind project. 

That, together with the shallow draught, means the whole thing can be assembled in relatively sheltered, moderate-depth water — you don't need the deep fjords that spar-type designs usually rely on.

Stability at sea is managed through a compressed-air trim system built into the floater's three columns. As the turbine yaws with the wind, the system pumps air into and out of the columns to keep the structure within a tight tilt tolerance, allowing it to produce power while sitting close to upright.

Built in Norway, powered by a fourth-generation floating wind base

Assembly took place at Wergeland Base, part of Wergeland Group, which has spent 70 years developing the Gulen industrial harbour into one of Norway's key sites for large-scale marine construction, including previous floating wind projects such as Hywind Tampen.

Culzean is a hugely important project for offshore wind and for Norwegian industry.

That's the words of Margunn Bjørnestad, CEO of Wergeland Group. "It's a strong demonstration that Norwegian and British sectors can work together to deliver new energy and support the transition. It also shows the value of the competence we already have from the oil and gas industry — logistics, heavy lifts, and the collaboration needed to keep a complex project on schedule, safely."

Bjørnestad said Culzean is the fourth floating wind project assembled at the base, with lessons from each project feeding into the next. 

We're very proud of the team. This shows Norwegian industry can do this — and that the potential here is real.

At peak, more than 100 people worked on the assembly at Wergeland, running around-the-clock shifts since the turn of the year to meet the schedule. Archer said the project was completed without any lost-time injuries.

Part of a wider scientific programme

Beyond proving the floating foundation itself, the Culzean pilot carries an extensive monitoring and research programme, with sensors tracking everything from structural loads to environmental effects on birds and fish in the area. Several French universities are involved in analysing the data, which the project partners expect to generate a body of published research on floating wind's interaction with the marine environment.

The project is one of 13 schemes awarded seabed rights under Crown Estate Scotland's Innovation and Targeted Oil and Gas (INTOG) leasing round in 2023, and is the first of those to be installed. It is now operated by NEO NEXT+ Energy, the independent UK producer formed in March 2026 through the merger of NEO Energy, Repsol UK and TotalEnergies' UK upstream business.

Project partners on the assembly and integration phase included Global Maritime, Navitas Renewables, Sarens and Archer Vertikal, alongside control-system supplier Origo Solutions of Kristiansand and monitoring-system provider IKM.

You can't overstate the importance of running pilots like this before scaling up.

That's Berge's main message. "You learn an enormous amount — about the technology, but also about cost efficiency — and that's exactly what will make the next projects succeed."