Flying Wind Turbines
- Ruairi Glynn
- On February 9, 2006
In the course of my research into making lighter-than-air interactive architecture I keep finding remarkable new applications for Dirigible technology. See the Space Lift and the Flying Radio Towers so while it may not be specifically interactive architecture, I thought I’d share these fascinating new approaches to sustainable power generation.
Wind turbines are constantly getting taller because everyone knows the higher you get off the ground, the better the wind speeds. But building big towers is expensive, especially if you want one 15,000 feet tall. So why not ditch the tower and make the windmill fly?
Several people are trying to do that. They’ve been written about before by others, but we’ve yet to tackle them, so here’s a little round-up of the three most notable projects: Sky Windpower, Laddermill, and Magenn. Each is a bit sketchy, but deserves to be given a shot. It seems obvious that once someone creates a workable system, it will become a huge winner, because of the sheer amount of power available up high: 1% of the jetstream’s wind power could supply all US electrical demand. Also, one of the main complaints about wind power is its intermittency–the wind doesn’t blow all the time, and so (according to Sky Windpower), most wind farms are only operating at their peak capacity 19-35% of the time. The wind is much steadier at altitude, so you get even more advantage over ground-based wind power. A final advantage is ad-hoc generation: devices with a reasonably simple tether-system do not have to be permanently installed in one place, they could be trucked out to any location that needed them.
Sky Windpower is the furthest along, with functional prototypes tested in the field. According to their figures, one flying windmill rated at 240kW with rotor diameters of 35 feet could generate power for less than two cents per kilowatt hour–that would make them the cheapest power source in the world. The flying windmills would initially get in position under their own power, using their motors to drive the propeller blades and helicopter upwards until they reached altitude. Then the motors would turn off and become generators as wind pushes the propeller blades, and the whirligig would float instead of fall because when tethered, the lift generated by the wind would overcome the craft’s weight as it also generates power.
Magenn is a more modest design, which makes it more feasible. The inventor is Fred Ferguson, a Canadian engineer specializing in airships. He envisions a range of devices from the household scale. Magenn’s design is radically different from other windmills on the market–it would not use propeller blades. Instead, it would be a helium blimp, with Savonius-style scoops causing it to rotate around motors at the attachment-points to its tether. The blimp-like design has several advantages: its Savonius scoop design lets it operate in winds as low as 2 mph; it is safer in a crash, because it would fall slowly and be mostly made of flexible material; it is safer for airplanes, because it sits below legally usable airspace; it is safer for birds, because the moving parts are visible and travel with the wind. The critic’s valid point is that the devices are currently vaporware, with not even a working prototype built yet. Despite this, Magenn has a distribution partner lined up, once they do get into production. It looks like the power-blimps would be mechanically simple and easy to build, so I would give them good odds of pulling it off by the end of the year, as promised. But it will no doubt take a few years before their invention is optimized and debugged.
Laddermill was a research project at TU Delft in the Netherlands. They imagined a series of kites strung together by cables into a loop hundreds of meters–possibly even a few kilometers–high. The kites would be computer-controlled to change their attitude and generate more lift from the wind on one side of the loop than the other. This would cause the entire loop to rotate, and its rotation would push a generator down on the ground to create electricity.
It sounds ludicrous, but the folks at TU Delft are smart, and we need to seriously investigate more out-of-the-box approaches. In some ways, this design is simpler than Magenn or Sky Windpower because it does not have to have the power-generation equipment aloft, and does not require a power-carrying tether, just a mechanical one. The elimination of power-generation hardware from the flying parts of the device also means that it should be safer, because the bits that can crash are small and light. I havent been able to find any information however on its development in the last 2 years so I’m unsure if its still being investigated.
Concept Videos & Images of Laddermill
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