Originally published 2021-06-29.
Image: Wind Catching Systems AS
The Windcatcher is a floating offshore wind design from the Norwegian company Wind Catching Systems. Instead of one giant turbine on a tall tower, it places dozens of small turbines in a huge square frame that floats at sea, rising higher than the Eiffel Tower. When the concept was unveiled in 2021, its developers said a single unit could supply enough electricity for about 80,000 European homes.
Is it real? Partly. The design exists on paper and in models, and in 2024 it received an approval in principle from the classification body DNV for a first 40 MW unit, which means the engineering was judged feasible enough to move to the next stage. As of the latest reporting we found, no full-size Windcatcher has been built at sea, and the 2023–2024 launch dates mentioned in 2021 were not met. This guide explains how the idea works, what the claims rest on, and what still needs to be proven.
Who is behind the Windcatcher
Wind Catching Systems AS was founded by Asbjørn Nes, a self-taught inventor, together with Arthur Kordt and Ole Heggheim. The company's pitch draws heavily on Norway's offshore oil and gas experience, where floating platforms anchored to the seabed have operated for decades in harsh North Sea conditions.
Speaking to IFLScience in 2021, the company's finance chief Ronny Karlsen described the origin of the idea simply: "It was trying to be creative, doing something else." His point was that the individual parts are familiar. The floating hull borrows from oil platforms, and the turbines are standard products bought from existing manufacturers. The new part is how they are combined into one structure.
How a wall of small turbines works
A conventional offshore wind turbine has three long blades on a single hub, and the industry has spent two decades making those blades ever longer. By 2021 the biggest machines were rated around 15 MW, with rotors over 200 metres across, and they have kept growing since.
The Windcatcher takes the opposite approach. Its frame holds a grid of many small rotors, each rated around 1 MW, stacked side by side and on top of one another. The whole frame, taller than the 330-metre Eiffel Tower in the published renderings, sits on a semi-submersible floating base moored in deep water, the same broad principle used by floating wind farms such as Equinor's Hywind projects.
Floating foundations matter because most of the world's strongest offshore winds blow over water too deep for turbines fixed to the seabed. Hywind Scotland, which started in 2017 with five floating turbines, showed that the approach can work commercially; the Windcatcher tries to fit far more generating capacity onto a single floating base.
The claimed advantages
Easier maintenance
Repairing a large offshore turbine usually means hiring specialised ships with heavy cranes, which are expensive and depend on calm weather. The Windcatcher frame includes a built-in lift so technicians can reach each small turbine from the structure itself and swap parts without a crane vessel. Karlsen told IFLScience that this was intended to cut operating costs, which make up a large part of the lifetime cost of offshore wind.
More output in strong wind
Big turbines reach their full rated power at a wind speed of roughly 12 metres per second. Above that, their control systems pitch the blades to limit the load, so output stays flat even as the wind strengthens. The company argued that its smaller rotors could keep working efficiently up to about 17 to 18 metres per second, capturing more energy in stormy conditions.
The multirotor effect
The developers also pointed to the multirotor effect, the idea that rotors placed close together can produce slightly more in total than the same rotors standing alone, because of the way air flows around and between them. Research on multirotor systems, including tests on a four-rotor demonstrator built by Vestas in Denmark, has reported small gains of this kind, on the order of a few percent. That is a real effect, but much smaller than headlines about "revolutionary" output can suggest.
Checking the 80,000 homes claim
Figures like "powers 80,000 homes" are estimates, not measurements, and they depend on several assumptions. A unit's rated capacity tells you its maximum output; actual annual energy depends on the capacity factor, which is the share of that maximum it produces on average over a year once calm spells, storms and maintenance are counted. Modern offshore wind often achieves 40 to 50 percent.
The other assumption is how much a home uses. Average household electricity use varies widely across Europe, and a home in Norway, where electric heating is common, uses far more than one in southern Europe. Change either number and the headline number of homes changes too.
A fair reading is that the 80,000-home figure was the company's own projection for a full-size unit under favourable assumptions. It is plausible in scale for a structure of over 100 MW in a windy location, but it will only become a record of performance once a unit operates for a full year.
Where the project stands
In 2021 Karlsen suggested that a Windcatcher could be in the water by 2023 or 2024. That did not happen. Instead, in mid-2024 the company announced that DNV had issued an Approval in Principle for a first 40 MW unit, described as the first of four planned for a wind farm, with later units potentially reaching around 126 MW each.
An approval in principle is a meaningful step, but it is an early one. It indicates that an independent reviewer found no fundamental barriers in the design. It is not a construction permit, a financing decision or proof of how the system will cope with years of waves, salt and fatigue. Many promising offshore concepts have stalled between this stage and a working prototype.
Common myths about giant wind designs
"Bigger always means better." Tall structures reach stronger winds, but the real test is cost per unit of energy over decades, including maintenance and insurance.
"Small turbines are less efficient than big ones." Individually, large rotors usually are more efficient. The Windcatcher's case rests on combining many small ones and simplifying maintenance, not on each small rotor beating a giant one.
"One structure can replace a whole wind farm." Even optimistic numbers put a single unit at the scale of a small wind farm. Meeting national climate targets still requires many gigawatts from many projects.
The Windcatcher is best seen as an interesting engineering bet: a way to borrow oil-industry know-how and off-the-shelf parts to make floating wind cheaper to run. Whether it lives up to the promise will be clear only when one is built and its output data are published.
Sources: Image credit Wind Catching Systems AS. IFLScience: The Windcatcher (June 2021); Olhar Digital: DNV approval in principle for a 40 MW Windcatcher (July 2024).
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