Bladeless Wind Turbines: Progress Or Quixotic?

The collapse of the Tacoma Narrows Bridge in 1940 provides a textbook example for physics students about the dangers of overestimating the force of oscillation and aeroelastic flutter.However, not everyone has taken it as a lesson in what to avoid, but rather how to capture the dangerous phenomena and put it to good use.

Vortex Bladeless, a start-up company based in Spain, has introduced a new type of wind turbine built around the idea of oscillation including a distinct feature: no blades. The bladeless turbine, invented by Daniel Yanez, generates energy not from a basic "windmill" design, but by oscillating to and fro as wind swirls around its cylindrical top. This is essentially using the principles of vorticity to harness the power of the wind, ironic in that prevention of vorticity has been the lesson most engineers have taken from the fate of the first Tacoma Bridge.

"This is a very good way to transmit energy from a fluid to a structure,” Yanez explains. Not to mention save money. The design has no excess gears or bearings needed to hold things in place, and does not come in fractured pieces that do not fit a standard storage transportation unit (unlike blades, which demand more customization for delivery the bigger each model gets). The cylinder poles in Yanez's design would also take up less space, cost half the amount of standard wind turbines to manufacture, make less noise, and crucial for the environmental lobby, be of minimal risk to birds' flight paths.

Of course there are downsides; being more lightweight taking up less area of wind to harness means less conversion energy. Wind turbines usually have a rate of 90 percent kinetic energy conversion, while Yanez believes his model will amount to somewhere around 70 percent (it also bears reminding Yanez and his partners have only built one miniature prototype right now). Also, there are those who question the idea of an oscillating pole being silent, especially at the size it will have to be in order to produce anything worth investment. “The oscillating frequencies that shake the cylinder will make noise,” says Sheila Widnall, an aeronautics and astronautics professor at MIT. “It will sound like a freight train coming through your wind farm.”

Vortex has already received about $1 million in venture capital to work with; it hopes to receive $5 million more to help build a larger version of its current prototypes. While Yanez and his compatriots agree there is a long way to go, if they have hit upon a model of wind turbine that can be improved and developed for more efficiency of space and integration into densely populated areas, they may have just invented the next generation of wind infrastructure.

Donal Thoms-Cappello is a freelance writer for Rotor Clip Company (www.rotorclip.com).