Flying windfarms

[Spin Echo]

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Reach for the sky: Could flying wind farms help beat global warming?

Wind energy far greater at high altitude

FEG (Flying Electric Generator) would hover at 15,000 feet

LONDON, England (CNN) -- James Bond would be lost without them -- those madcap gadgets merging two technologies that help him beat the bad guys and save the planet. The underwater watch with a built-in Geiger counter, for example; or the car that doubles as a submarine; or the exploding bagpipes and missile-launching wheelchair.

Now a U.S. company has taken a leaf out of 007's book and developed a similarly unlikely "combination" technology.

The "villain" in this case is not a psychotic, cat-stroking megalomaniac, but something both more prosaic and, potentially, more threatening -- global warming: in particular, how to meet the world's energy needs without swamping the planet with clouds of atmosphere-clogging pollutants.

And the madcap gadget that might just provide a solution? A helicopter that doubles as a wind turbine. Or, to give it its technical name, a FEG (Flying Electric Generator).

The brainchild of Australian engineering specialist Professor Bryan Roberts, the FEG is being developed by San Diego-based company SkyWindPower.

Code-cracker turned turbine enthusiast

The latter is headed by David Shepard, who started his career cracking Japanese military ciphers during World War Two, and went on to create the Farrington B numeric font that appears on credit cards around the world.

Shepard has long been convinced of the need for a new global energy source to reduce reliance on carbon-emitting fossil fuels.

For the last two decades his attention has focused on the electricity-generating potential of high-altitude winds, and when he learnt of Professor Roberts' prototype "gyromill" -- a flying wind turbine that the Australian had been developing since 1979 -- he decided it offered the best model for realizing that potential.

The two men started working together in 2002, and the FEG is the result.

High-altitude winds

The guiding principle of the FEG is that wind speed and constancy are far greater at high altitude than they are on the ground, especially in the two major jet streams - the Sub-Tropical Jet and the Polar Front Jet - that exist in each hemisphere (at around 30 degrees and 60 degrees latitude respectively).

A turbine at great height, so the theory goes, can generate far more power than a similar turbine at or near ground level. It has been estimated that capturing just one percent of the available energy of these high altitude winds would meet the electricity needs of the entire planet.

"The winds a few miles above the mid latitudes of the Northern and Southern Hemispheres are far stronger and more persistent than the winds just above us," Shepard told CNN.

"This results in potentially being able to generate electricity for over eighty percent of the time, as opposed to thirty percent of the time at ground-based wind turbine sites.

"The largest ground-based wind turbines currently produce about five megawatts each. We expect typical FEGs to produce about 20 megawatts each."

Helicopter technology

But how do we get a working turbine up to the necessary height -- at least 15,000 ft (4600 meters) above the earth's surface? That's where helicopter technology comes in.

Taking the form of a giant H-shaped frame, the prototype FEG has four huge blades at the four points of the H, each blade 10.7 meters (35 feet) in diameter. These act like the rotors of a helicopter, lifting the FEG to the required height.

Once in place, the blades not only keep the FEG air-born, providing lift like the surface area of a kite, but also act as turbines, turning dynamos within the platform that generate electricity, which is transmitted back to earth through a vast aluminum tethering cable.

An in-built GPS (Global Positioning System) uses satellite technology to ensure that the FEG always remains in the same place, both vertically and horizontally.

According to Shepard, development is already at an advanced stage.

"Professor Roberts demonstrated a FEG in Australia at an altitude of sixty feet over a decade ago," he told CNN.

U.S. demonstration in three years

"We expect to make a demonstration in the U.S. less than three years from now at high altitude in normal high altitude winds. In four years I would expect this sort of technology to be in active use."

As with ground-based wind farms, Shepard envisages whole "sky-farms" of FEGs hovering above the earth in restricted airspace.

Forty-three such FEG "arrays" -- each comprising 600 FEGs -- would, he estimates, generate sufficient electricity to power the whole of the U.S.

"Our calculations show that by reserving less than one four-hundredth of U.S. air space, located at relatively remote locations not on airway routes, all of America's electrical energy needs could be met," he says.

"That is considerably less airspace than is already restricted for other purposes, primarily military."

Not only would the FEGs provide clean energy -- the feedback from environmental groups, according to Shepard, has been overwhelmingly positive -- but at less cost than conventional electricity generation.

While each FEG would cost an estimated $2,260,000 to build, maintain and support, arrays of FEGS would, in the long term, prove extremely cost effective, generating electricity at about 2 cents per kilowatt hour, as opposed to the 3-5 cents of conventional generating methods.

There are risks, of course. Even in restricted airspace there is the possibility of collision with aircraft that unwittingly -- or illegally -- stray into that airspace.

Likewise, despite numerous design features aimed at ensuring the stability of the air-born FEG, the possibility of the structure malfunctioning and plummeting to earth cannot be excluded.

Crashes "inevitable"

"Inevitably crashes will occur," the SkyWindPower Web site acknowledges, "Just as airplane crashes occur.

"Statistically, however, FEGs should be just as reliable as commercial airliners, whose safety records are incredibly good.

"And FEGs don't take off or land at airports teeming with people in and around them."

Shepard and Roberts are not the only people to have considered harnessing the power of high-altitude winds.

Magenn Power, a Canadian company, have been developing a helium-filled, medium altitude wind generator, while in the Netherlands Laddermill has been exploring similar ground using kite technology.

SkyWindPower's FEG, however, is at the forefront of the field, with the U.S. government showing considerable interest in the prototype helicopter-cum-wind-turbine.

Whether it will provide a definitive solution to the world's ever-increasing energy needs remains to be seen.

With the effects of global warming and climate change becoming increasingly acute, however, a technology that might once have been dismissed as no more than a James Bond fantasy now looks as if it could have a serious role to play.

They might not be quite as sexy as your average Bond adventure, but flying wind turbines could end up generating a lot more heat than 007 and Pussy Galore ever did.

Sweet. I'm looking forward to the working demonstration.

[Andrew_Fireborn]

When I read that, I thought "Blimps with turbines"... Wonder exactly how these work. The Blimp I thought, because they're virtually neutrally bouyant, they'd stay up through that principle, allowing all power to be tethered back down to the ground...

Wonder how much power they take to start up. Obviously they generate enough in air to stay up and send a good amount back down. I guess they could conceivably be run and kept aloft purely by wind... but that screams 'no contengency plan.'

"Inevitably crashes will occur," the SkyWindPower Web site acknowledges, "Just as airplane crashes occur.

"Statistically, however, FEGs should be just as reliable as commercial airliners, whose safety records are incredibly good.

Honestly, it would have a better one. Since they can likely afford to take them offline for required maintenance. A large number of airline crashes are because they won't take planes out of service for necessary upgrades, (in some exceptionally bad cases, even required maintenance...) instead writing off the lives and vehicles lost as a store might write of shop lifting losses...

And people wonder why I hate to fly on commercial lines. (Ok, acrophobia, an splitting earaches cause by landing are also factors...)

[Sikon]

Tapping the relatively great power of the jet stream is an interesting idea.

Obtainable generation from wind power per unit area goes up exponentially with wind speed to the third power, for a given air density:

The mass of air flowing through a given area per unit time is linearly proportional to wind speed, while its kinetic energy per unit mass is proportional to velocity squared, making its total power per unit area be proportional to velocity cubed.

Of course, there's a fair amount of inefficiency for any rotor capturing wind power, but that doesn't matter for the general trend of obtainable power scaling with V^3.

That extreme sensitivity to wind velocity can cause trouble sometimes with wind generation. As a random example, if a turbine is rated for 1 MW power generation at 10 m/s wind speed, the obtainable power drops to 1% as much if wind speed drops to 2 m/s at a given time. Overall, the typical capacity factor of regular (ground-based) wind generation is around 30%, with the turbines obtaining around 30% of rated power on average when placed at relatively good locations.

However, this idea benefits a lot from the third power scaling of wind power with velocity, and it could have a much higher capacity factor as they imply in the article. Although jet stream velocity varies somewhat, the jet stream is fairly reliable.

And it is very powerful compared to ordinary, lower altitude winds.

As a random example, even after adjusting for around 40% the density of ground level air, when there is air in a jet stream going 50 m/s (110 mph), that corresponds to 15 times the power per unit area of low altitude wind going 15 m/s or 400 times the power per unit area of low altitude wind going 5 m/s.

Of course, a flying wind array is going to tend to cost more than a ground windmill to construct relative to its size, but the size required for a given amount of power would be so vastly less. The net effect might be better economics than ground wind generation, perhaps. Although most new businesses fail for a variety of reasons, this does have much potential.

[Sea Skimmer]

Wonder how much power they take to start up. Obviously they generate enough in air to stay up and send a good amount back down. I guess they could conceivably be run and kept aloft purely by wind... but that screams 'no contengency plan.'

It should be possible, in the event of a sudden loss of wind velocity, to send power back up the 15,000ft extension cord, and use that to run the generator as a motor. I think they’d pretty much have to have that capability anyway, to provide a means by which the turbine initially achieves its operating altitude.

Ideally we could build these things in parallel with a new web of nuclear plants (not to mention the US’s desperate need of an improved grid of high tension power lines) , which would provided the voltage to even out the output of all the wind turbines. But unfortunately its extremely likely that practical issues of safety and airspace, not to mention people thinking the idea just doesn’t ‘look right’ are going to keep it from becoming a reality.

[Knife]

Saw some thing the other day on Discovery about this, they also had the idea of doing something simular but off the coast and under water to use the tides.

[CaptainChewbacca]

Saw some thing the other day on Discovery about this, they also had the idea of doing something simular but off the coast and under water to use the tides.

They're already using tidal generators in parts of New York City, they show great promise.

[Knife]

Saw some thing the other day on Discovery about this, they also had the idea of doing something simular but off the coast and under water to use the tides.

They're already using tidal generators in parts of New York City, they show great promise.

Hmm you'd think the coasts would be awash in such things. Hell even amonst most rivers. I was up on Oregon a couple months ago, driving along the Columbia river with the Dallies power plant. That river is so fucking long and of good size, can't see why there wouldn't be a couple more power plants using it to power Oregon and Washington.

[CaptainChewbacca]

Saw some thing the other day on Discovery about this, they also had the idea of doing something simular but off the coast and under water to use the tides.

They're already using tidal generators in parts of New York City, they show great promise.

Hmm you'd think the coasts would be awash in such things. Hell even amonst most rivers. I was up on Oregon a couple months ago, driving along the Columbia river with the Dallies power plant. That river is so fucking long and of good size, can't see why there wouldn't be a couple more power plants using it to power Oregon and Washington.

The best places are deep rivers with strong tides, and the Hudson is perfect for that sort of thing. Coastlines aren't ideal for the kind of device I saw.

[salm]

The best places are deep rivers with strong tides, and the Hudson is perfect for that sort of thing. Coastlines aren't ideal for the kind of device I saw.

These tidal generators have been around since the 60s IIRC. And the Brits just created an offshore variant of theses things.

[Colonel Olrik]

The best places are deep rivers with strong tides, and the Hudson is perfect for that sort of thing. Coastlines aren't ideal for the kind of device I saw.

These tidal generators have been around since the 60s IIRC. And the Brits just created an offshore variant of theses things.

If you mean what I think you do those are not tidal generators, they're wave energy generators. As long as the part of the ocean where they lie is agitated enough, they're viable. A commercial farm (I think the first and until now only in Europe) is now generating energy off the coast of Portugal (the Atlantic coast is great for this).

[salm]

The best places are deep rivers with strong tides, and the Hudson is perfect for that sort of thing. Coastlines aren't ideal for the kind of device I saw.

These tidal generators have been around since the 60s IIRC. And the Brits just created an offshore variant of theses things.

If you mean what I think you do those are not tidal generators, they're wave energy generators. As long as the part of the ocean where they lie is agitated enough, they're viable. A commercial farm (I think the first and until now only in Europe) is now generating energy off the coast of Portugal (the Atlantic coast is great for this).

No, i´m talking about real tidal power plants. The first one built was in France in the 60s.

Here´s a Link.

The offshore tidal power plant i´m talking about is in Britain:

Link

They use the tidal forces as opposed to the wave energy generators which use the up and down movement caused by the waves if i understand correctly.

[Colonel Olrik]

Thanks, salm. I hadn't seen those before.

[LMSx]

Like Andrew_Fireborn, I was thinking Zeppelin/Blimp type things, but that's probably due to my exposure to videogames with air ships in them.

Both technologies, high-altitude wind farms and underwater generators sound really interesting. I hope something comes from this real quickly.

[Gil Hamilton]

I know that Florida is looking to heavily invest in underwater wave generators, due to the fact that they've got vast amounts of coastline and of all the energy that Florida consumes, which is alot, most of it comes from hydrocarbons not produced locally.