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There's really no point in flying solar cells, they don't work any better than down on Earth, and they shade what's under just the same. It's quite pointless, if you ask me. If you're going to fly something, use the flying aspect of it to generate power. What a let-down.

IMHO the way of using flying-anything for power has been demonstrated by Makani Power. I somehow trust Makani's engineering a tad better. They've been a bit more open about their engineering process, and they have some pretty damn good talent. Oh, and their areal power density (per are of flying "stuff") is at least order of magnitude better than an ideal 100% efficient solar cell would be. So, meh. Big meh.

No. You are wrong and stupid. Please do some research.

Makani’s Airborne Wind Turbine (AWT) can create inexpensive energy, in more locations than traditional wind turbines, because it flies where the wind is stronger and more consistent.

The Makani AWT can transform wind power:

* Produces power at up to half the cost of traditional wind turbines
* Accesses the stronger and more consistent winds at altitude
* 90% less material than a conventional turbine, it is less expensive to build and install
* Opens up large new areas of wind resource, including the vast resources offshore above deep water
* Allows for deployment outside of visually or environmentally sensitive locations

The Makani AWT is a practical solution:

* Requires no more space than conventional turbines
* Capable of handling large, sudden shifts in wind speed and direction
* Redundant, fault tolerant design
* Lightning hardened

If you actually went right to the source, you wouldn't be repeating tired old silliness. For your edification: in a standard wind turbine, the outermost part of the propeller blade is generating most of the energy. The rest is essentially dead weight. Makani's approach cuts the weight by roughly an order of magnitude. They can also operate in slower winds, and they can operate higher when the wind is faster and more stable. Never mind that their tethered airplane automatically copes with wind gusts - the tail realigns the wing to face the apparent wind. Standard turbines need to use relatively slow and bulky high-torque servos to adjust the blade pitch. Such an adjustment's time constant is an order of magnitude longer than what you get in Makani's approach.

Look at the space and structure required. Now consider the fragility and lack of stability as compared to a standard wind turbine in the same spot.

How could anyone seriously consider this idea to be better than a standard wind turbine?

Oh! By the way, the company's co-founder died unexpectedly 7 months ago.

Not that Google cares about this tiny bit of money, but this is wasted money, to be sure.

Asked and answered.

Ok, here is the actual answer to your question. Sorry about the other posts.

Well, a few clicks confirms that suspicion. No word on weight, but I think the scale of the thing says it all, really.

Sounds like the wing itself is modeled after a turbine blade, so the wind is simultaneously holding it up and causing it to generate power. From the pictures, the thing looks pretty small (not much longer than the truck in the same pic) and it's presumably really light, depending on what materials they're using to construct them. My guess is carbon fiber, but I'm no engineer.

Wind turbines that operate well above the ground most emphatically ARE being built, and I'm surprised this fact hasn't more thoroughly penetrated the slashdot consciousness given how "sexy" this tech is. I have biases because I work in this field and have met most of the major players, but IMHO the two companies that are marching most rapidly towards utility scale aerial wind power are Makani power and Ampyx power:

http://www.makanipower.com/
http://www.ampyxpower.com/

In particular, Makani power's 30kW Wing 7b (same as wing 7a but with more aerodynamic turbine cowlings) is hitting their predicted power curve perfectly, and they're already working on their next wing. Ampyx is also using (way more efficient) rigid wings, but they do their power generation on the ground, which has a bunch of advantages and disadvantages. I'm not sure which design will ultimately be more efficient/practical (and this may depend on scale), but at the rate they're going it will certainly be hard to beat Makani to market. Also, for better or worse, national differences in the way airspace is regulated may play an accidental role in preventing the industry from rapidly standardizing on one design. Currently the FAA is (tentatively) regulating Makani's turbines as structures, and the govt. in the Netherlands is (tentatively) regulating Ampyx's turbines as aircraft. Note that there are a bunch of other start-ups working on AWE as well; the above two are just the ones I consider most promising for utility scale power.

There are several startups working on exploiting high-altitude wind energy. The basic idea is to have something flying in the air, instead of building very large towers. Two of the more advanced companies are:

Makani Power (Bay Area): They build a small plane that is tethered to the ground. It flies circles in the sky, the propellers are the generators.
http://www.makanipower.com/

Enerkite (Germany): They launch a kite into the air, also tethered to the ground. A generator attached to the cable generates energy most of the time while the cable is unrolling. From time to time, energy generation is stopped and the kite is pulled in.
http://www.enerkite.de/

It is yet to see which concept will win (leightweight kite: + easy and cheap, generator on the ground; - hard to launch, no direct flight control, generation stops in regular intervals; airplane: + much better flight control; generators can be used to launch and land; - much more complex, heavier).

Cringely (I know, I know) had a lot to say about these guys and Google's $10M investment in them a few weeks ago.

It's all about high-altitude kites!

Pete Lynn works for Makani, and had a series of posts to Google Groups in 2003 that explained the concept. There's also an old web page of his that's only available on the Internet Archive.

That's the interesting part about Google's initiative -- they're looking to solve this problem on the (relative) cheap, in years and with millions instead of decades and billions.

Makani power are planning to generate electricity using high altitude kites - at a cost competitive with coal power.

There's very little information about them for now but they did get a $10M investment from Google. Here is what Cringely dug up about them from old Usenet posts of one of the team members.