The "Windcatcher": Bigger Than The Eiffel Tower And Can Power 80,000 Homes, Say Developers


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

The Windcatcher

The Windcatcher is bigger than the Eiffel tower, and it might be the future of renewable energy. Image credit: Wind Catching Systems AS

Look, unless humanity manages to get its act together on the climate crisis, the future is looking to be one of war, displaced peoples, and deep poverty divides. The good news is, there are a bunch of people out there coming up with some really ingenious solutions that are changing the way we use energy in the modern world and making a cleaner future a real possibility.

And one environment-saving innovation that we may be seeing in the near future is perhaps the most striking yet: the Windcatcher. The brainchild of self-taught inventor Asbjørn Nes, the Windcatcher is a huge offshore “sail” that might be set to radically change wind power generation.


And when we say “huge”, we mean “bigger than the Eiffel tower”:

Ooft. Image credit: Wind Catching Systems AS

The Innovation

Although it’s not the only design available, one particular kind of turbine has dominated the wind power industry: the Horizontal Axis Wind Turbine. You know which one this is – it’s a tall pole supporting vast blades that rotate, giving the impression of a kind of space-age windmill. And while this is evidently an effective design, particularly on land, Nes, along with fellow entrepreneurs Arthur Kordt and Ole Heggheim, wanted to know whether this millennia-old technology was really the best or most efficient way to generate power in the 21st century.

“It was trying to be creative, doing something else,” Ronny Karlsen, CFO of Wind Catching Systems AS, told IFLS. “How can you change what’s currently being done – that’s the definition of innovation.”


The Windcatcher would be a vast offshore structure, Karlsen explained, where even conventional wind farms have seen incredible success. But instead of simply reproducing the designs that already populate the oceans, the founders of Wind Catching Systems drew instead on their backgrounds in the maritime and oil and gas industries.

“The technology of having a floating structure offshore is well known, especially in the oil and gas industry,” said Karlsen. “You have floating oil rigs that are [fixed] to the sea bed and stationary.”

“The turbines that we have in our system [are] off the shelf,” he continued. “They are produced by many of the turbine producers. But the innovative [part] is the design – how you put this all together into one system that is different from everything else out there currently in the market.”

The Problems With Current Wind Farms


The world has never been more invested in renewable energy. But while none of them match fossil fuels in terms of damage to the environment, every new development seems to come with its own problems: solar power can be intermittent, hydroelectric dams can harm local wildlife, and geothermal power can be expensive and hard to access.

The same is true of wind power. Although wind provided the world with more than five percent of the world’s energy in 2019 – a figure that looks set to increase with recent policy changes across the world – the renewable power source nevertheless has its detractors.

One problem with offshore wind farms is maintenance costs – operation and maintenance can typically account for 25–30 percent of a wind farm’s total lifecycle cost. In this regard, the Windcatcher has an advantage, according to Karlsen.

“Currently with offshore wind, you … need a lot of specialized vessels with cranes to reach the turbines,” he explained to IFLS. “What we’re going to do is to build an elevator system … so that you can actually do all the maintenance and repairs without having these specialized offshore vessels available. That reduces our operating cost.”


Another concern for renewable energy going forward is how to maximize potential output. Although significant strides have been made in this direction for wind power, Karlsen explained to IFLS that there are still some hurdles to overcome.

“With conventional turbines – when the wind speed reaches 12 meters per second (m/s) they will start pitching the blades,” he explained. “The electricity will still be produced, but it will not increase above 12 m/s wind … they do this to not have the blades spin around too fast.”

In contrast, the blades in the Windcatcher can spin much faster – up to 17 or 18m/s. That’s in part because the individual rotors are much smaller, explained Karlsen. And not only does this mean that the Windcatcher should be able to generate more power in higher winds, it also circumvents a big problem in conventional offshore wind farms: the wake effect.

“The wake … is a function of how large your rotor is,” Karlsen told IFLS, “and we actually do think that the wake effect of our units will be lower due to smaller rotors.”


But that’s not all, he explained.

“There's also something called the multirotor effect: the tests … show that having combining several small rotors close to each other, in sum they produce more power than if you have each one standing individually,” Karlsen told IFLS. “It’s because of the turbulence they create for each other – [it] actually increases the production.”

“There’s a lot of … science here,” he said.

One wind catching unit produces enough electricity for 80,000 European households, according to the inventors. Image credit: Wind Catching Systems AS

Mitigating the Risk


One aspect of wind power – or any renewable energy source for that matter – that is always a concern is its potential impact on local biodiversity. The evidence for the effect of offshore wind farms on marine life is mixed and complex, but it is certainly true that they can have a less-than-positive impact on birdlife (albeit nowhere near as bad as fossil fuel power stations).

“This is something we are taking very seriously,” Karlsen told IFLS. “We are evaluating bird radar – looking at systems they use at airports, where they have airguns – this is something we are actually working on including in the design.”

Among the bird-saving techniques the structure will use, Karlsen explained, are black blades to increase visibility – a strategy that has been shown to be dramatically successful in conventional wind farms. But the company hopes that their design should intrinsically be safer for birds than current turbines, for one gigantic, Eiffel-tower-sized reason.

“What we’ve been told – and it needs to be verified – is that since this is almost like a wall of turbines, a bird wouldn’t … fly straight through it. It would be very visible,” Karlsen said. “One of the problems you have with … conventional rotors is that it seems like they’re spinning around slowly, but they’re not. They’re spinning around really fast, so the bird thinks oh I can fly through here, I see nothing – and then suddenly a blade comes around.”


“We hope that this thing is more visible to birds, and they’d think twice of flying through it,” he added. “It’s something many people asked us, and that we're taking seriously … we’re looking at all options, and if anyone has good suggestions, we’re always willing to talk.” 

When Will We See Them?

Although the designs are impressive, we won’t be seeing the Windcatcher in our oceans just yet, Karlsen told IFLS. At the moment, the company, in collaboration with engineers at Politecnico di Milano, is focusing on developing and proving the technology behind the invention.

“There’s a long timeline on these projects,” he said. “We are qualifying the technology … we’re doing those tests as we speak, and we expect to get the results in the autumn. That’s … the next technical milestone.”


If all goes to plan, Karlsen explained, the Windcatcher should be ready for construction sometime next year – and we might see the colossal structure in the ocean by 2023 or 2024.

“We want to talk to anyone who develops wind farms,” Karlsen told IFLS. “Developing a wind farm is a massive project run by the big energy companies of the world, and we hope that they will evaluate our technology and see the potential in it.”

“What we’re trying to do is to find an environmentally friendly and cheap solution of generating renewable energy,” he added. “That’s our goal.”

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