The North Sea off Jutland’s west coast is flat, cold and grey in September.
Fourteen miles out, an installation vessel called Brave Tern is doing something that should not look possible from the deck.
It is raising a steel turbine assembly to a height that leaves the finished machine standing nearly 486 feet above the waterline.
Then it sails back to port, reloads, and comes out again.
Half of the 72 turbines at Denmark’s largest offshore wind farm are now standing. So what does it actually take to stand one up in open water?
How you stand a turbine up in open water
Every turbine at the Thor offshore wind farm is rated at up to 15 megawatts and stands around 486 feet above sea level. The rotor blades run 377 feet long each. Put the tip of one blade at a goalpost and the other end reaches past the end zone, across the running track and well into the parking lot beyond.
The vessel doing the lifting is a jack up ship. Its legs lower to the seabed and then push the hull clear of the water, turning a ship into a fixed platform that neither rolls nor heaves while the crane works. That stability is the whole mechanism.
A crane hook hanging from a floating hull moves with the swell, and the bolt flange at the top of a foundation offers no tolerance for a tower section that is swinging. Lift the hull out of the water and the crane works from something closer to a pier than a boat.
What the installation vessel actually does
Installation runs depart from the Port of Esbjerg, with Brave Tern able to transport and install three turbine sets per cycle. The wind farm site sits roughly 14 miles off Thorsminde, further up the Jutland coast, so each cycle means a loadout in port, a passage to the field, a run of lifts, then the trip back for more steel.
Each turbine arrives at the site in sections: tower, nacelle and blades. The crew builds the machine upward in a sequence of crane picks. Then the vessel jacks back down, moves to the next foundation and repeats the whole routine.
Every reposition costs hours. That is why Brave Tern carries sets in batches of three rather than one at a time, and why the pace of the campaign is measured in cycles rather than in individual lifts.
The foundations waiting on the seabed
The steel monopile foundations went into the seabed the year before the turbine vessel arrived. Each monopile runs around 330 feet long and weighs up to 1,500 metric tons, and they were installed by a heavy lift vessel working out of Eemshaven in the Netherlands, five at a time.
Thor skipped the arrangement most offshore projects use. Instead of a monopile topped by an overlapping transition piece, extended single piles were driven directly, and the secondary steel, boat landings, access platforms and internal cassettes, was fitted offshore afterward from the Danish Port of Thyborøn. Reusable hard covers capped the open pile tops through winter, protecting them until the towers arrived.
That sequencing matters for the tower bolt pattern. The landing flange is part of the driven pile itself, so pile verticality has to be right the first time. There is no collar later to correct a lean before a tower goes up nearly 500 feet.
What the numbers say and where they come from
The operator’s own installation update confirms that 36 of the 72 turbines were in place at the halfway milestone announced in July 2026, with the remaining 36 scheduled by the end of the year. The total rated capacity of the completed farm is 1,080 megawatts, which makes it Denmark’s largest offshore wind farm. Once fully operational, it is expected to supply the equivalent of more than one million Danish households.
Trade coverage of the earlier foundation campaign records that all 72 foundations were in and fully equipped by November 2025, with the last monopile set that September. For context on how that compares with earlier Danish work, one vessel handled the full set of foundation tubes for a previous farm, and the covers capping their open tops were designed to be taken off and used again.
Sustainability features are built into the hardware, not bolted on afterward. Thirty-six of the towers use steel manufactured with a lower carbon footprint, and 40 of the turbines carry 120 recyclable rotor blades between them. For a sense of how the industry handles hardware already retired, blades pulled off a 250 megawatt Kansas wind farm are being cut into transmission poles instead of buried.
The operator put it plainly in its July update: the project is on track to deliver first power to Danish homes before the end of the year.
What winter means for the schedule
The North Sea does not stay workable indefinitely. Jacking down and lifting a rotor several hundred feet in the air both have wind and wave limits, and those limits are met more often as autumn turns to winter, so the campaign is paced by weather rather than by the calendar.
The operator expects the remaining machines to be installed by the end of 2026, with testing and commissioning running into spring 2027 and full commercial operation targeted that year. Power is already flowing: the first turbines fed the Danish grid in March 2026, months before the halfway mark was reached.
Either way, the bulk of the lifting is done. Thirty-six machines are already standing in the North Sea, and the vessel is loaded for the next run out.
