Windstalks

[Patrick Degan]

Not sure if this system will work as promised, but I just find the concept of it fascinating:

Noise from wind turbine blades, inadvertent bat and bird kills and even the way wind turbines look have made installing them anything but a breeze. New York design firm Atelier DNA has an alternative concept that ditches blades in favor of stalks. Resembling thin cattails, the Windstalks generate electricity when the wind sets them waving. The designers came up with the idea for the planned city Masdar, a 2.3-square-mile, automobile-free area being built outside of Abu Dhabi. Atelier DNA’s “Windstalk” project came in second in the Land Art Generator competition a contest sponsored by Madsar to identify the best work of art that generates renewable energy from a pool of international submissions.

The proposed design calls for 1,203 “stalks,” each 180-feet high with concrete bases that are between about 33- and 66-feet wide. The carbon-fiber stalks, reinforced with resin, are about a foot wide at the base tapering to about 2 inches at the top. Each stalk will contain alternating layers of electrodes and ceramic discs made from piezoelectric material, which generates a current when put under pressure. In the case of the stalks, the discs will compress as they sway in the wind, creating a charge.

“The idea came from trying to find kinetic models in nature that could be tapped to produce energy,” explained Atelier DNA founding partner Darío Núñez-Ameni.

In the proposal for Masdar, the Windstalk wind farm spans 280,000 square feet. Based on rough estimates, said Núñez-Ameni the output would be comparable to that of a conventional wind farm covering the same area.



“Our system is very efficient in that there is no friction loss associated with more mechanical systems such as conventional wind turbines,” he said.

Each base is slightly different, and is sloped so that rain will funnel into the areas between the concrete to help plants grow wild. These bases form a sort of public park space and serve a technological purpose. Each one contains a torque generator that converts the kinetic energy from the stalk into energy using shock absorber cylinders similar to the kind being developed by Cambridge, Massachusetts-based Levant Power .

Wind isn’t constant, though, so Núñez-Ameni says two large chambers below the whole site will work like a battery to store energy. The idea is based on existing hydroelectric pumped storage systems. Water in the upper chamber will flow through turbines to the lower chamber, releasing stored energy until the wind starts up again.

The top of each tall stalk has an LED lamp that glows when the wind is blowing -- more intensely during strong winds and not all when the air is still. The firm anticipates that the stalks will behave naturally, vibrating and fluttering in the air.

“Windstalk is completely silent, and the image associated with them is something we're already used to seeing in a field of wheat or reeds in a marsh. Our hope is that people living close to them will like to walk through the field -- especially at night -- under their own, private sky of swarming stars,” said Núñez-Ameni.

After completion, a Windstalk should be able to produce as much electricity as a single wind turbine, with the advantage that output could be increased with a denser array of stalks. Density is not possible with conventional turbines, which need to be spaced about three times the rotor's diameter in order to avoid air turbulence. But Windstalks work on chaos and turbulence so they can be installed much closer together, said Núñez-Ameni.

Núñez-Ameni also reports that the firm is currently working on taking the Windstalk idea underwater. Called Wavestalk, the whole system would be inverted to harness energy from the flow of ocean currents and waves. The firm’s long-term goal is to build a large system in the United States, either on land or in the water.

[madd0ct0r]

that's a hell of a lot of carbon fibre to equal one turbine. pretty though.

The wave stalks could be intresting - there's more energy there I think.

[Starglider]

That would be immensely expensive, quite inefficient (the reason why piezo generators aren't in wider use) and completely uneconomic. Cool design though.

[Eleas]

That would be immensely expensive, quite inefficient (the reason why piezo generators aren't in wider use)

Each one contains a torque generator that converts the kinetic energy from the stalk into energy using shock absorber cylinders similar to the kind being developed by Cambridge, Massachusetts-based Levant Power .

The Levant-type shock absorber has nothing to do with piezoelectricity.

[Eleas]

Ghetto edit: This sounded like criticism of Starglider's point, but he's right; the article does mention piezo. Odd. If you have piezoelectric materials already, why the emphasis on shock absorbers? To siphon the bled-off energy that the piezo doesn't handle?

[Starglider]

If you have piezoelectric materials already, why the emphasis on shock absorbers? To siphon the bled-off energy that the piezo doesn't handle?

According to the article, the stalks contain piezoelectric discs, while the bases have pistons driving hydralic motors that in turn drive generators. I admit that I just assumed from the render that the piezo discs would be caputring most of the energy, since they show much more bending than tilting. That said the hydralic system is going to be pretty inefficient as well compared to a normal smoothly rotating directly geared generator, plus unlike solid-state piezo generators all the hydralic articulating bases will require regular maintenance. The power output from this thing would be bursty as hell, much worse than even the dubious capacity factor of conventional wind power. You can smooth that with energy storage but that just piles expense upon expense. The whole thing reads like a Popular Science puff piece rather than an engineering proposal; the 'there will be no friction' line is a blatant lie given that the base joints / hydralic cylinders / piping / hydralic motors / generator bearings will certainly experience friction.

[Ziggy Stardust]

Yeah, this looks like horseshit to me. Starglider already covered most of it, but I am also extremely dubious of the claim (assuming that everything else were to work as advertised) that it would be "completely silent." I mean, over a thousand 180-foot structures bending and vibrating with the wind? It is going to get noisy in the middle of all that. Also, how would all of this stand up to a major storm? With unpredictable, varying wind patterns, would some of these start hitting each other?

[Napoleon the Clown]

They'd do that or just snap outright. Carbon fiber is strong but not invulnerable. And from what I understand, extremely flammable.

And yeah, that's a ton of carbon fiber. Which isn't exactly cheap. Somehow I don't see this panning out.

[Simon_Jester]

Has this been tested at all, or are these guys proposing a totally pie-in-the-sky project?

[Korvan]

Not sure this will stop bird deaths, unless the waving stalks scare off the birds. Flying through that would be like sassing off to 1000 nuns all armed with rulers.