Sunk into the Danish North Sea in just 5 months, 72 steel towers each weighing up to 1,500 tons are waiting for the turbines that carry the offshore wind industry’s most ambitious recycling bet yet

The North Sea floor off Denmark’s Jutland coast has swallowed a great deal of steel over the centuries.

Most of it was not placed gently.

But between April and September 2025, a single heavy lift vessel lowered 72 enormous steel cylinders into the seabed with unusual precision, one after another, working through summer swells and autumn squalls.

Denmark has a population of roughly six million people, meaning a single wind farm will supply power to a community the size of Copenhagen and Aarhus combined.

Each cylinder was roughly as tall as a ten story building.

Each one weighed as much as a fully loaded freight train.

And when the last one settled into the sand, the construction team had done something even seasoned offshore engineers had not expected: finished early.

The question now is what those 72 waiting pillars will eventually carry, and what that cargo means for the wider wind industry.

A harbor town with its eye on the horizon

The Port of Esbjerg, on Denmark’s windswept west coast, has spent decades in the business of offshore energy.

First it was oil and gas platforms rolling out on barges into the North Sea.

Now turbine towers and nacelles queue on its quays, destined for an offshore wind farm called Thor, roughly 20 kilometers off the Jutland shoreline.

The port’s crane operators and logistics crews know the rhythm of these jobs.

They also know that Thor is not a routine project.

When turbine installation begins in 2026, Esbjerg will be the staging base for what will become, at 1,080 megawatts, the largest offshore wind farm ever built in Danish waters.

That distinction is easy to say and harder to picture until you stand beside the foundations already waiting offshore.

What 1,500 tons looks like going down

The vessel responsible for planting Thor’s foundations was Jan De Nul’s Les Alizés, a purpose built ship for work that most cranes on land could not attempt.

Over five months, all 72 monopile foundations were successfully installed, each around 100 meters in length.

At that size, a single foundation displaces more metal than a small naval destroyer.

Lowering one into the seabed requires the vessel to jack itself up on legs above the waves, hold itself perfectly still, and drive the pile home with a hydraulic hammer that can be heard kilometers away.

The porpoises and harbor seals that feed in those waters were given their own protection zone around every active hammer site.

Steel that tries to leave a lighter mark

Thor has been engineered with an unusual degree of awareness about what large scale offshore construction actually costs the planet.

It will be the first offshore wind farm in the world to use 36 turbine steel towers manufactured with a lower carbon footprint.

Steel production is one of the most carbon intensive industrial processes on Earth, and an offshore wind farm consumes an extraordinary tonnage of it.

Half of the turbines will also be equipped with recyclable rotor blades.

Wind blade recycling has been one of the industry’s most awkward unsolved problems for years, with old fiberglass rotors typically heading to landfill or incineration.

Thor represents the largest deployment yet of blades engineered from the outset to be recovered and remade.

What the sea floor is holding

The project takes its name from the Norse god of thunder and storms, which feels apt for a structure planted in one of the world’s busiest stretches of open water.

According to RWE’s release, when it reaches full operation in 2027, Thor will produce enough electricity to supply the equivalent of more than one million Danish households.

Denmark has a population of roughly six million people, meaning a single wind farm will supply power to a community the size of Copenhagen and Aarhus combined.

Operations and maintenance will be run from a new service building at the Port of Thorsminde, a small harbor town on the Jutland coast expected to create 50 to 60 local jobs.

For a community built around fishing and coastal trade, those are jobs with a generational significance that no lease payment can fully capture.

The wait, and what comes next

To protect the monopiles until turbine towers are mounted in 2026, innovative reusable hard covers have been installed on each foundation.

Such covers are usually disposed of after use because they are made to fit a specific project.

The covers used at Thor are reusable, reducing waste and increasing circularity.

It is a small detail, but it rhymes with the larger ambition: nothing wasted that does not need to be.

Turbine installation is scheduled to begin from Esbjerg in spring 2026, with 72 Siemens Gamesa machines destined for the waiting foundations.

Recyclable blade technology is still maturing, and the supply chain needed to recover and reprocess those rotors does not yet exist at the scale the industry will eventually require.

Thor proves the blades can be built.

Whether the recycling infrastructure follows is the next test, one the entire supply chain will be watching.

For now, 72 steel columns stand in the Danish North Sea, holding their ground against the same storms that gave this farm its name, waiting for the blades that might finally close the loop.