Vertical wind turbines
THE IDEA BEHIND THE Vortex-Bladeless-TECHNOLOGY //
Vortex Bladeless is a technology start-up. We are developing an environmentally friendly wind generator that does not require rotor blades or rotation . It is a new technology designed for modular on-site power generation and off-grid low consumption systems, specifically designed to work with other Vortex devices or regular solar panels.
Our vortex wind turbine is not a turbine as it does not rotate. It is based on the phenomenon based aeroelastic resonance , from the wind to the emission of energy harnessing of Karman 's vortex it , a process called vortex shedding or vortex street . In this way, the device oscillates with a silent motion, allowing it to be placed perfectly anywhere, without lubricants or disturbing animals.
All the physical principles of current wind machines are also applied to Vortex, it's just a different and innovative way to harness energy from wind.
CURRENT STATUS 2020
After deciding to focus on the end-user market with small devices to simplify manufacturing, testing and optimisation, we have launched a first and modest series of Vortex Nano devices with a height of 85 cm into industrial production. Although they are still assembled by hand, the vast majority of the parts of this equipment have been prototyped using industrial chain processes (moulding, filament winding, poltrusion, etc.) to the ones we worked with before.
This, along with major advances in our generator + magnetic-aeroelastic tuning system (which converts motion into electrical energy and maintains synchronisation with the frequency of vortices in different wind ranges), has allowed us to arrive at these small Vortex Nano devices that we can begin to proudly show off. These devices are not yet products, they are not yet fully certified and have a long optimisation path ahead of them, like any other innovative technology that has just entered the market.
For the time being, around 100 units will be manufactured by the beginning of 2021 and will be distributed worldwide, mainly in Europe, especially in Spain. The recipients are not yet end users, but NGOs, universities, independent laboratories, municipalities, nature parks and partner companies around the world. The aim is to obtain measurements, study their behaviour in different locations and types of installations, and generate metrics to improve the devices and understand their long-term behaviour according to the variables of the environment.
The next logical step would be to increase the sample size and put these small wind turbines in the hands of end users. To this end, a second and perhaps even third public beta campaign of 1,000 to 10,000 units is planned, where anyone can request a Vortex Nano unit to test it, give us feedback on it and become part of the Vortex Bladeless project as a beta tester. If these actions are taken, it will be done after the current campaign of 100 units is over, after collecting data and making necessary changes to the designs. No date has been set yet.
Will the Vortex Nano become a commercial product? What is the market and applications for this device?
The Vortex Nano is too small to be a wind turbine. More than small wind turbines, we could be talking about nanowind (hence the name), and therefore the maximum energy it can produce per hour is small compared to the smallest existing commercial wind turbines. And yet there are millions of potential applications for such a device, and this is because the technology is radically different from other wind technologies on the market, resulting in features and benefits that may be preferable when selecting a wind energy source .
Obviously, a large market for such devices is currently dominated by low-power photovoltaics, especially off-grid. And yet, it is very rare to see small wind turbines next to low-power solar, as they require constant maintenance and their performance at low wind speeds leaves much to be desired. All this makes traditional small wind or nanowind devices unprofitable and sometimes unfeasible for many applications.
Of course, one should not think of installing a single Vortex device, just as one should not think of installing a single solar panel. Since these devices only require a distance in open space around them equal to half the height (r=h/2) for proper operation, they can be placed very, very close together compared to conventional wind turbines rows, arrays or grids of them, with only a fraction of the space that would be needed for the same number of regular turbines of similar size.
Similarly, we don't know if Vortex Nano will ever become a commercial product in use, or remain in a corporate and government infrastructure application, or remain in our initial beta test. We also want and hope to give our close community the opportunity to have one in their homes and test it in the near future.
On the other hand, we haven't forgotten about Vortex Tacoma! We still have our sights set on our 2.75m high unit, which we hope to finish developing with everything we learn from this beta test of the little ones. It is clear that we will need a lot of help to bring larger units to the factory or to be able to produce a larger number of smaller units! Especially from industry partners who want to join us on this hardware adventure. Do not hesitate to write to us here !
THE BLADELESS TURBINES
Vortex Bladeless Biography & Current Phase
Vortex is a vertical, slim and cylindrical wind generator. It consists of a fixed part to which the device is attached to a basement, and a flexible part that acts as a boom interacting freely with the fluid in a swinging motion.
It could be divided into two parts; mast and base . Oddly enough, one of the most difficult parts is to industrialise the manufacture of the mast while maintaining its characteristics. At the moment, some methods are feasible, but we are still testing alternatives to optimise it.
Because of its brilliant design, it has no gears or moving parts in contact, so it doesn't need oils or lubricants. Operating the device couldn't be easier, almost plug-and-go , it requires hardly any maintenance and running costs . All these features make it perfect for distributed energy.
The alternator converts mechanical energy into electricity. It counts with neodymium magnets and its stator is inside the handset of the device.
When converting mechanical energy into electrical energy, the alternator dampens the induced oscillatory motion and at the same time is able to change the natural oscillation frequency of the bladeless turbine structure, thus increasing the lock-in range while maintaining the resonance frequency at higher wind speeds, we call this tuning system . Unlike conventional wind turbines, this phenomenon is able to change the apparent elasticity constant of the structure, which depends on the vibration amplitude, so that it increases with increasing wind speed.
Despite its simplicity, 6 families of registered patents protect the design and technology worldwide. For more information, visit our technology page .
OUR STORY OF BECOMING A TECH STARTUP //
As with any project of this kind, the first steps for entrepreneurs are hard. A tech startup is even more complicated, as you need to develop before manufacturing and produce efficiently before selling. Of course with passed certification, no mistakes from industrialisation processes, proper quality control and post-buy services.
There are still many things to do and many goals to achieve before Vortex Bladeless becomes a full-fledged member of the wind industry. In this article, our coCEO Raul recalls the steps that got us here .
With our own funds, the project started in 2010 in Deutecno , our first tech startup, where we developed electronic noses. When the idea of the Vortex was born, we built a modest wind tunnel and started testing. Our proof of concept was a simple water bottle attached to a stick that oscillated by the force of the wind. We found proof that there was energy conversion there that could be harnessed.
Vortex Tech StartupWe soon realised all the funding we would need to get this idea off the ground. Deutecno Noses was sold and a few months later we built a more sophisticated technological demonstration that impressed the judges of the Repsol Foundation's Entrepreneurs Fund. At the beginning of 2014, thanks to CDTI's Neotec funds and a group of business angels who are still with us, the technology startup Vortex Bladeless SL was founded and the Technology principles were validated at an early stage in the laboratory and in real environment tests.
To start real development and provide computing resources, simulation software, machines and tools, and materials for the first prototypes, the company decided in early 2015 to launch a successful crowdfunding campaign for research purposes, which attracted the interest of global media .
To capture the imagination of the scientific community and new strategic partner, in 2015 Vortex goes to Boston, USA, to present our idea to MIT and let the project become known worldwide, becoming trending topic in the field of renewable energy for months.
On the other hand, NGOs and other environmental organisations such as Birdlife have shown great interest in this solution and have also offered their cooperation, as Vortex may have less impact on nature and fauna if larger devices are built in the future.
In June 2016, the European Union Commission ( EASME ) included the Vortex project in its Horizon 2020 programme . Since then, we have been working restlessly to optimise the technology. The goals projected in 2015 were perhaps too ambitious for a start-up, so we decided that Vortex Tacoma would be the largest device currently under development.
In 2017 and 2018, our special collaboration with the Barcelona Supercomputing Center ( BSC ) , the company Altair , the Microgravity Institute of the Universidad Politécnica of Madrid and many other technology centres was key to our success in the various milestones we faced; being able to juxtapose computational and experimental results at a high level before reaching a working product.
In 2019, we started to look at the certification and industrialisation processes of manufacturing, while evolving and optimising to bring out a Minimum Viable Product as quickly as possible. In 2020, this will pay off and we will finally install pilots in public places for more extensive field testing. Interesting times ahead!
The future of wind power technology?
If solar power is the king of renewables, wind power is undoubtedly the queen. Vortex wind generators are more similar to solar panels than normal wind turbines in terms of functions and cost efficiency over time. We have been working very hard for years. It has not been easy to find out the best ingredients and the best way to prepare this particular recipe, although we are very close to our goal and dream .
The team at Vortex is working restlessly to optimise the final steps and get homologation for sale. For the milestone of efficient assembly of bladeless turbines here in Spain, we are looking for industrial partners in Europe who can supply materials and manufactured parts.
In the meantime, the company is looking to launch a beta testing campaign where participants can purchase one of the world's first Vortex wind generators, the Vortex Nano , from the factory, a small but fully functional tech demonstration that can power a USB device like a wind-powered powerbank. Of course, feedback is collected to improve our final product, Vortex Tacoma, as quickly as possible.
You can keep up to date with Vortex developments in our newsletter and social channels! Thank you very much.
// Basics of the idea
Vortex Bladeless is a resonant wind generator with vortex-induced vibration. It uses wind energy from a vorticity phenomenon called vortex shedding. Basically, the bladeless technology consists of a cylinder attached vertically with an elastic rod. The cylinder oscillates on a wind field, which then generates electricity through a light machine system. In other words, it is a wind turbine that is not actually a turbine.
Vortex wind generators are becoming more like solar panels than normal wind turbines in terms of functions and cost efficiency over time.
``Project funded by the Horizon 2020 Research and Innovation of the European Union``.
STRUCTURE & GEOMETRY
The outer cylinder is designed to be largely rigid and able to vibrate, and remains anchored to the lower rod. The top of the cylinder is not constrained and has the maximum amplitude of vibration. The structure is made of resins reinforced with carbon and/or glass fibre, materials used in conventional wind turbine rotor blades.
The top of the rod supports the mast and the bottom is firmly anchored to the ground. It is made of carbon fibre reinforced polymer , which offers great fatigue resistance and has minimal energy loss when oscillating.
Of course, the design of such a wind turbine is very different from a conventional wind turbine. Instead of a tower, nacelle and blades, our device has only a mast made of lightweight materials above a base. This reduces the use of raw materials and the need for deeper foundations .
Vortex turbine design
Our bladeless wind turbine captures energy from the wind through a resonance phenomenon created by an aerodynamic effect called vortex shedding. In fluid mechanics , as the wind passes through a blunt body, the flow is altered , creating a cyclic pattern of vortices. Once the frequency of these forces is close enough to the structural frequency of the body, the body begins to oscillate and resonates with the wind. This is also known as vortex-induced vibration (VIV).
How it works
Retrieved from: Duke University
Vortex technology, fluid dynamics
This VIV phenomenon is often avoided in civil engineering, aviation and architecture. On the contrary, Vortex turbines maximise these aerodynamic instabilities and wind turbulence and capture this energy.
Vortex's mast geometry has been specifically designed to achieve maximum performance at the average observed wind speeds. It is able to adapt very quickly to changes in wind direction and turbulent air flows often observed in urban environments.
The disturbance of the downstream wind flow is the reason why normal turbines have to be installed far away from each other. This has no effect on bladeless wind turbines, any restriction due to the " wake effect " is avoided. In addition, we expect vortex units to work better together and give feedback to each other when they have the right amount of free space around them, estimated at half the total height of the unit. In normal wind turbines, this free space is usually five times the total height of the unit.
``Designed specifically for the consumer market and distributed energy grids``
THE VORTEX ALTERNATOR
Currently, Vortex generates electricity through an alternator system , consisting of coils and magnets adapted to vortex dynamics, without gears, shafts or rotating parts. Our Vortex generator is currently considered a "small wind turbine".
Alternators are a well-known technology, although the way Vortex uses them is innovative and patented. This design allows for reduced maintenance and eliminates the need for lubrication.
Wind generator design
A. Fixed part of the stator
B. Mobile part of the alternator
C. Support of the stator
The frequency of vortex shedding is proportional to the speed of the wind flow, but each structure has its own natural frequency of vibration. To match wind frequencies with the natural frequency of a device, you should change, among other things, the body mass (the more mass, the less natural frequency) and the stiffness (the more stiffness, higher frequencies). Therefore, you need complex mechanisms to vary the natural frequency of this device.
To avoid this, the Vortex design instead uses a magnetic confinement system with permanent magnets that increase the apparent stiffness of the system according to their degree of flexion. The degree of flexion increases as the wind strength increases. We call this a "tuning system".
As a result, Vortex's patented self-synchronisation system allows effortless detection of a wider range of wind speeds with a switch-on point in about 3 m/s (starting speed). It can automatically vary the stiffness and "synchronise" with the incoming wind speed to stay in resonance without mechanical or manual intervention. In this way, the lock-in range of the aerogenerator increases .
// Von Karman Vortex Effect
The vortex street effect or vortex shedding effect was first described and mathematically formalised in 1911 by Theodore von Kármán, the genius of aviation. This effect is produced by lateral forces of the wind on an object immersed in a laminar flow. The wind flow creates a cyclic vortex pattern that can become an engineering challenge for slender structures such as towers, masts and chimneys. One such example is the collapse of the Tacoma Narrow bridge in 1940, USA.
How it works
``Vortex successfully adjusts its natural frequency to resonate with the frequencies of the wind within a wide range of wind speeds``.
UNDERSTANDING THE OSCILLATION
The idea behind the vortex wind turbine is that the same forces can be used to generate energy. When the wind vortices match the natural frequency of the structure of the device, it begins to resonate and thus oscillate, allowing the bladeless wind turbine to use the energy from this motion as a regular generator.
You will find many examples of the vortex shedding effect in everyday life. Based on this principle and taking into account some other physical phenomena such as Betz's law , finite body aerodynamics, turbulence regions, wind gradients, etc., the Vortex team has created many computer models that shed light on the right geometry and parameters to develop and improve the efficiency of the Vortex design.
Although 2D simulations are very interesting to us, VIV is a 3D phenomenon. Interactions between vortices along the device have been described by other authors. Since we are dealing with a new technology, we need to create new models and confirm their validity. These 3D simulations are based on the Reynolds number , an important dimensionless quantity in fluid mechanics that is used to predict flow patterns in different flow situations
Large computational resources are needed. We are working hard with Altair simulation software to find the best way to achieve optimal results with an affordable amount of computational resources and time. We also collaborate with the Barcelona Supercomputing Center and use their computational and expert resources.
Vortex oscillation principle
MATERIALS & SERVICE LIFE
Current wind turbine technology has to accommodate very different load levels at variable wind speeds, which places high mechanical demands on transmission components such as gears, bearings, bushings or brakes. The many moving parts are subject to constant wear, which leads to high maintenance costs.
In bladeless wind turbines, mechanical elements that can wear out due to friction are completely eliminated. The main materials used in the manufacture of vortex turbines are carbon fibre polymers, plastics, steel, neodymium and copper. The operating limits of these materials are far from Vortex's operating standards.
Vortex Tacoma (2.75m) - Under development, not yet available!
Stress & Fatigue
Of course, this wind turbine is not immune to fatigue and stress forces. Fatigue is defined by the weakening of a material by repeatedly applied loads or forces. The rod of the vortex turbine suffers continuous bending and material failure may eventually occur. The first products were developed with this issue in mind.
The carbon fibre rod was developed for a maximum vibration amplitude of 2.7º. This implies a very low material deformation . Computerised and mathematical analyses carried out on the component most affected by this fatigue phenomenon lead us to believe that the vortex aerogenerator will have a long service life.
One of the main advantages of vortex turbines is the low cost associated with them. We have estimated that the cost of electricity (LCOE) of vortex turbines will be lower, allowing a faster return on investment. In any case, more research needs to be done on this topic to be able to say with certainty.
Stepped cost energy
This makes this technology very competitive not only with generations of alternative or renewable energy, but even with conventional technologies. You can read a study on the economics of bladeless turbines here .
These cost reductions result from clever design and use of raw materials. Nacelle, support mechanisms and rotor blades, which are usually costly components in conventional wind generators, are not required.
Thanks to the very low weight and centre of gravity close to the ground, anchoring or foundation requirements have been significantly reduced compared to conventional turbines, making installation easier.
``Vortex is linked to NGOs, universities and top tech research centres worldwide``.
In wind energy conversion, electricity generation is proportional to the area swept by the wind turbine. Vortex currently sweeps up to 30% of the working area of a conventional 3-blade-based wind turbine of the same height.
As a result, we can generally say that vortex wind power is less energy efficient than normal horizontal axis wind turbines. On the other hand, a smaller swept area allows more bladeless turbines to be installed in the same area, thus balancing energy efficiency with space efficiency in a more cost-effective way.
The estimated rated power of Vortex Tacoma (2.75 m) is 100 W after industrialisation.
Vortex Bladeless Technology
NO BRAKES REQUIRED
INSTALLED POWER DENSITY
ANY SPEED POWER
QUIET CLEAN ENERGY
In urban environments, wind currents are usually very turbulent, this is a problem for normal wind turbines. In addition, the wake of conventional wind turbines is problematic when several wind turbines are installed together in one location.
On the other hand, conventional wind turbines need an orientation system to counter the incoming wind flow. Vortex wind generators no longer need it due to its circular cross-section.
The VIV effect is based on fluid turbulence. Consequently, this bladeless wind generator adapts very quickly to changes in wind direction and intensity, regardless of turbulence. A fully developed laminar wind flow is not required for effective operation of a vortex turbine.
Vortex Bladeless is mainly a solution for decentralised power generation. It is perfect to be placed near a house or above the roof. It can operate off-grid and as part of a hybrid solar plus wind generation system.
Its simple design and light weight allow for very efficient use of raw materials. No complex manufacturing process is required to build a bladeless wind turbine, although current methods of industrialising production must be significantly different. The absence of lubricants makes the disposal of this waste unnecessary.
The total weight of a Vortex Tacoma is estimated to be less than 15 kg after industrialisation. Unlike normal rotating wind power, we expect Vortex technology to be completely silent when properly calibrated and anchored. In addition, the interference of the Vortex Bladeless design with radio signals is negligible.
Although small wind turbines are not normally a significant problem for local wildlife, the impact of bladeless wind power on bird populations is expected to be much less. Vortex's design allows for oscillating motion in bladeless turbines that is tiny and less aggressive than conventional wind turbines, so wildlife is not disturbed and birds and bats can easily avoid them as they fly.
The NGO Birdlife is working with us to measure these impacts. Wind energy and birds can share the same wind!
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ONE OF THE FIRST VORTEX TACOMA TURBINES IN THE TEST PHASE ©VORTEX BLADELESS
2020 was the year of success for wind power. Especially due to the increased construction of wind farms in China, more wind turbines were connected to the grid worldwide in 2020 than ever before. A startup from Spain now wants to bring an alternative to classic wind turbines to the market as soon as possible. The start-up Vortex Bladeless is working on a wind turbine that will generate energy from wind power without the characteristic rotor blades of wind turbines. Instead, the energy is to be generated purely by the oscillations of the machine, by weighing it backwards and forwards in the wind, and the resulting vibrations.
The start-up has already been working on its model for several years and has also received funding under the EU's Horizon 2020 funding programme. However, the model is not yet ready to compete with classic wind turbines. After the first pilots of the 2.75-metre-high Vortex Tacoma were set up for a field test in 2020, the Vortex Nano turbines, a mini wind turbine, are to start operation in a pilot phase in 2021.
Vibration generates energy
Externally, it is somewhat reminiscent of wind turbines, where the "head" with the rotor blades has been forgotten and so only the foot is in agriculture. The way it works is reminiscent of little figures that stand on the car's dashboard and move along with the car's movement. The principle of energy generation is based on vibrations. An elastic rod is attached to the rigid base in the form of a cylinder. When this moves, electricity is generated by a generator. The aerodynamic effect of vortex-induced oscillation is exploited. This should enable the start-up's wind turbines to generate maximum wind energy even when the wind blows only moderately.
Energy efficiency is lower than with wind turbines
According to Vortex Bladeless, their wind turbines have several advantages over traditional wind turbines. For example, less raw materials are needed in their construction and they are supposed to be much lighter, so that they need a less deep foundation for a firm stand. This should also reduce the costs of construction and the investment in such a rotor-less wind turbine should pay off more quickly. The wingless wind turbines are also supposed to be quieter and less dangerous for birds and bats. However, as the start-up also admits, the energy efficiency of their turbine is lower than that of a conventional wind turbine. But this should be eradicated by the possibility of erecting more of their narrow turbines on the same area.
The Vortex Nano turbine is expected to provide new insights for further research ©Vortex Bladeless
THE VORTEX NANO PLANT IS EXPECTED TO BRING NEW INSIGHTS FOR FURTHER RESEARCH ©VORTEX BLADELESS
Pilot phase with 100 mini plants planned
However, the Vortex Bladeless systems are not yet available on the market. A production of 100 mini wind turbines is now planned for 2021. The Vortex nano-turbines are only 85 centimetres high and are now to provide information on necessary further developments. The energy efficiency of the nano-plants is rather low, as the start-up admits. They are to be sent to universities, nature parks or other public institutions around the world, but primarily in Spain and Europe, in order to gain knowledge about their use in practice. These findings will then be used to continue work on the Vortex Tacoma. In an interview with the Guardian, the founder of the start-up stated that in the future he also wants to build large installations with a height of 140 metres. With these, it should then be possible to generate energy of up to one megawatt.
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Rotorless wind turbines: chic but useless?
The Spanish start-up Vortex Bladeless is developing a new type of wind turbine that does without rotor blades. The concept sounds interesting, but experts see several weak points.
MIT Technology Review
Spanish start-up Vortex Bladeless is developing a new kind of wind turbine that doesn't require rotor blades. The concept sounds interesting, but experts see several weaknesses.
Larger, more efficient turbine designs are delivering ever higher power, so wind power has become a serious energy source in recent decades. In 2014, the industry saw record global investment of $99.5 billion, but gradually the growth of turbines may be reaching its limits.
Transport alone is increasingly difficult due to the size of the components: individual rotor blades and tower segments often need special trucks and straight, wide roads. In addition, today's wind turbines are already incredibly top-heavy. The generators and gearboxes on platforms 100 metres up can weigh more than 100 tonnes. As the length and weight of propellers increases, so do the material costs for wider and sturdier towers, as well as the cost of component maintenance, which partly eats away at the efficiency benefits of larger turbines.
Time and again, the renewable energy industry has tried to solve these problems - but so far without success. The latest proposal, however, amounts to radically different wind turbines: a cylinder without a rotor at all, which is caused to oscillate or vibrate by the wind.
The concept comes from the Spanish start-up Vortex Bladeless. Its turbines make use of so-called vorticity, i.e. the vortex dynamics in wind and fluids. When wind hits one of the cylindrical turbines, vortices are created, especially on its lee side. This causes the cylinder to oscillate, and this kinetic energy is converted into electricity by a linear generator similar to those used to harness wave energy.
David Yáñez, one of the company's founders, came across this concept in his student days when he was studying the collapse of the Tacoma Narrows Bridge in Washington. The bridge collapsed in 1940 due to strong vibrations triggered by crosswinds - a textbook example of engineering failure. Yáñez actually saw a lesson in it: "It's a very good way to transfer energy from a fluid to a solid."
In Vortex's lightweight cylinder design, there are no gears or bearings. Yáñez says it should be able to generate electricity 40 per cent cheaper than conventional wind turbines. The company has so far raised $1 million in capital from private investors and the government and is seeking another $5 million. Yáñez says a 4-kilowatt system will be launched in 2016, followed by a much larger 1 megawatt system around 2018.
This sounds promising, but as with any radical new idea in the energy sector, there are plenty of sceptics about rotorless turbines.
"In a conventional wind turbine with rotors, the blades sweep a large area," says Martin Hansen, a wind power expert at the Technical University of Denmark. "With Vortex, you have nothing but a rod."
Oscillating cylinders can not only capture less wind energy, but also turn only a smaller proportion of it into electricity, Hansen adds. Conventional wind turbines typically convert 80 to 90 per cent of the kinetic energy of their spinning rotors into electricity. The conversion efficiency of Vortex's custom-built linear generator will be 70 per cent, according to Yáñez.
That only a smaller area is covered with vibrating turbines and that the conversion efficiency is lower, Yáñez acknowledges. However, lower manufacturing and maintenance costs would outweigh these disadvantages.
However, if the company builds taller turbines to take advantage of the higher wind speeds at higher altitudes, it will run into other problems arising from the physics of fluid mechanics. When air or fluids flow past small-diameter cylinders at low speeds, they do so in a smooth, constant motion. With wider cylinders and higher wind speeds, however, the flow becomes turbulent and produces chaotic eddies. This causes the oscillation frequency of the cylinder to vary, making it difficult to optimise electricity production.
"With very slender cylinders and very low speeds, you get singing telephone wires - a perfectly clean frequency or tone," explains Sheila Widnall, professor of aeronautics and astronautics at MIT. "On the other hand, if the cylinder is very big and the wind is very strong, you get a range of different frequencies. You can't get as much energy then because the oscillation is fundamentally turbulent."
Widnall also questions Vortex's claim that its turbines are almost silent. "The oscillation frequencies that move the cylinder will make noise," she says. "It will sound like a goods train going through the wind farm."
Oscillating cylinders are just one of many new technologies aimed at generating more wind power with less effort. Makani Power, for example, is developing "energy kites" - connected to a ground station, they fly large circles in the air similar to the tip of a conventional rotor blade and produce electricity from wind with small turbines on board. Makami was acquired in 2013 by Google X, Google's semi-secret research unit. Its head Astro Teller said this March that the first tests with a 600-kilowatt kite would soon begin.
Correction: A previous version of the text incorrectly referred to a "rotorless wind turbine". This is of course misleading. We have now corrected the headline as well as the text with the term "wind turbines". We have also corrected the wording "wind and other fluids" - this actually refers to "fluid", an expression from fluid mechanics. It is used for gases and liquids.
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Wind turbines are becoming increasingly important for electricity supply, yet citizens in many places vehemently oppose new wind farms. Vertical wind turbines like those from Vortex Bladeless could become an alternative. They generate electricity without rotors from vibrational energy.
Why classic wind turbines are unpopular
In a survey by the Fachagentur Windenergie an Land, 79 percent of respondents said wind energy use was important. However, many do not want the turbines on their own doorstep. Time and again, the start of construction for new wind farms is delayed, sometimes for years, by complaints from local residents. The wind turbines are too loud, dangerous for birds and destroy the landscape, they say again and again.
How vertical wind turbines work
The wind turbines of the Spanish start-up Vortex Bladeless can compensate for some of these disadvantages. At first glance, they are not recognisable as wind turbines: they have no rotors and thus look more like columns. At three metres high, they are also much smaller than classic wind turbines.
How do such wind turbines generate electricity? The turbines are firmly anchored in the ground. The wind sets the upper part in motion, based on the aerodynamic effect of vortex-induced oscillation. This oscillation energy generates electricity via a generator.
Cheaper electricity, but less power
The idea came to David Yáñez, one of the founders of Vortex Bladeless, when he was studying the collapse of the Tacoma-Narrows Bridge in Washington. The suspension bridge collapsed in 1940 because strong winds had caused it to vibrate so much that its cables broke.
This vibration energy is also used by the rotorless wind turbines that Yáñez is developing today. The advantage of the turbines is that they do not need gears and therefore require less maintenance and are more durable. This should also make the electricity generated cheaper. Vortex Bladeless estimates that the electricity from the vertical wind turbines can be 40 per cent cheaper than that from conventional wind turbines.
Moreover, the turbines are supposed to deliver their maximum energy even when there is only moderate wind. Unlike conventional wind turbines, they do not pose a danger to birds, nor do they generate noise or the so-called cast shadow from the rotors, about which residents repeatedly complain.
The disadvantage of the small turbines is that they generate less electricity than the huge wind turbines, some of which are well over 100 metres tall. But on the other hand, they could be placed anywhere where there is no space for large turbines - in the city, for example. There they could become part of a decentralised power supply. In the countryside, they can be connected to form small wind farms.
Vortex Bladeless quotes a price of 300 euros for a small wind turbine. It delivers 100 watts, which is about 20,000 times less electricity than a classic wind turbine. In the future, however, the Spanish start-up wants to develop larger systems that generate up to one megawatt of power. Vortex Bladeless has been working on the idea for several years and has received funding from the EU's Horizon 2020 programme.
The first test phase is underway
The idea is still in the test phase. In 2021, Vortex Bladeless will produce a small series of 100 copies of the Vortex Nano, a small unit only 85 centimetres high. They will go to NGOs, universities, municipalities, research laboratories, nature parks and partner companies, where they will be tested and thus provide important data for the further development of the idea. In the next step, end consumers are also to be included in the tests.
Whether these vertical wind turbines will become a noteworthy contribution to the energy transition will therefore only become clear later. For the Norwegian energy company Equinor, Vortex Bladeless is in any case one of the ten most interesting start-ups in the energy sector.