Kirigami-inspired solar panels
The ancient art is inspiring the design of solar cells so they can change shape to catch the sun
As a new self-consumption solution, this technology uses vibrating masts that can be installed almost anywhere.
The world's largest wind turbine is expected to start operating in 2026. It will generate 16 MW, enough to power 20,000 homes, and have 387-feet blades while standing 866 feet tall, almost shoulder to shoulder with the French Eiffel Tower. It's a sign of the potential of offshore wind energy, which is exploring revolutionary designs like this pyramidal turbine we talked about recently. As far as this type of green power is concerned, wind turbines based on blades have unbeatable efficiency. However, these structures are bulky and not very functional in urban spaces, especially for self-consumption. How can this be solved?
One of the ways to achieve more compact wind turbines would be to opt for vertical axis turbines, i.e., turbines that rotate on themselves. However, there are more radical solutions, such as dispensing with any rotating element. A Spanish company has resorted to a concept called aeroelastic resonance to create masts without blades that generate electricity through vibration.
By way of a brief explanation, when air passes through a circular structure, vortices are created along its path, and when their frequency matches the resonance frequency of the structure, the latter begins to absorb energy. This is technically known as vortex shredding.
The new bladeless wind turbines consist of a fixed vertical cylinder on an elastic rod attached to the ground. The cylinder oscillates in a specific wind speed range and then transforms the mechanical energy into electricity utilizing an alternator. Technically, it is not a turbine, as there is no rotating element.
Everyday materials such as fiberglass or carbon fiber are used, which facilitates their construction. The fact that there are no rotating parts reduces maintenance and component wear.
Every material with the ability to vibrate has a particular resonance frequency. This means that a standard fiberglass mast only resonates when the wind blows with a certain intensity. However, the distinctive feature of these new wind turbines is that they use a patented mechanism with magnets that modify the stiffness of the cylinder depending on its oscillation amplitude and the degree of core flexing. The stronger the wind, the greater the amplitude of oscillation. The inventors of the technology call it a "tuning system."
The prototype they have developed has been named Tacoma -in honor of the mythical bridge that went into resonance and jumped into the air- and has a height of about three meters, a weight of fifteen kilos, and an electrical generation capacity of 100 watts. They are also studying the creation of smaller models of sixty centimeters in height that would be used to charge sensors in remote areas.
The main model, on the other hand, is designed for installation on urban rooftops, as it is very quiet and can operate in turbulent winds. In addition, it does not require a specific orientation to generate energy, and unlike wind turbines with blades, several units can be installed next to each other without interfering with each other.
The company has so far carried out several installations in universities and town halls in the province of Ávila, but a commercial model is yet to reach the market. By the end of 2022, they will test the feasibility of a wind turbine between nine and ten meters high. Who knows if, combined with solar farms on rooftops and solar glass, they will become an ally for greener and more sustainable cities.
Innovation in the wind energy sector is not only limited to new designs or anchoring technologies in the case of floating offshore wind power but is also aimed at improving the functionalities of existing wind turbines. One of the most exciting avenues of research in recent times is the addition of solar panels to windmill masts.
Thanks to this initiative, carried out at the Breña wind farm in Albacete, the wind turbines have electricity to supply the turbine's internal systems, even without wind. In addition, flexible and fully recyclable organic solar panels have been used, reinforcing the project's sustainability.
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