uh, how does this work again?

From the article:
"A kite generates power by pulling on a string attached to generators on the ground. When it has reached its maximum height, it is reeled back down to repeat the process."

So we let wind pull the kite upward running a generator creating electricity. Then we real the kite back in, against the wind, using electricity. Doesn't this just cancel itself out?

My old boss posed an interesting question about green energy. How will harvesting these natural resources impact the world in unforeseen ways? After all of these years its clear how cutting too many trees and burning fossil fuels has impacted the world - what issues will emerge from our new 'better' ambitions? For instance plants depend on wind to strengthen their trunks (blowing in the wind tears tissue which grows back stronger, similar to how our muscles strengthen). If we harvest too much wind will we have weak trees so they blow over in small storms?

I'm a big fan of green initiatives and fully support them but I'd like to hear what people think about the future impacts of harvesting natural resources that are currently dedicated to other purposes in the world.

Cool. This certainly looks like it saves on material costs compared to turbines. How far apart do the kites need to be spaced? I don't know if the 10kW output is because this is just an early version or because of a systemic problem, but since turbines can be several megawatts each, I wonder about efficient use of land.

Also, I know that at higher altitudes the wind is steadier, but surely even there it isn't always windy. Is it? What holds the kite up when the wind speed falls too low? How often would that be a problem? I like the idea. I'm just curious these questions are answered.

Good question Chris. Unfortunatley only time can tell. No one could ever guess all of the future impact. They say a butterfly flapping it's wings can affect the weather on the other side of the world. The same must be true for reducing the strength of the wind. It could change weather patterns and even climate. Our very existance changes our world, good or bad. Idealy we will change it for the better, but if we change it for the worse mother nature will take out her furry on us and the human race will exentually go extinct. Life, however, will go on.

Is this a picture of an existing rig or just a Photoshop? Kite-based wind energy will be huge. But I'd like to see real demo units and results data.

christopher,

There is no problem harvesting "too much" wind because you can't run out and wind turbines do not block wind, they redirect a VERY small amount to the generators. Even those that cover acres of land will not affect windspeed. The Great Wall of China represents the pinacle of this, if a wall that large doesn't affect windspeed (outside a very localized area, i.e. right next to the wall) nothing will.

The image shown here is a photoshop - check out the linked guardian article for video of the actual experiment.

It will be interesting to see how well this can be executed. It seems non-trivial to generate power from a wind source that is unsuitable for turbines.

10kw is probably not enough for 10 american households - your hairdryer or microwave may consume more than 1kw. Even conservative estimates I have seen usually put american household average power consumption at 1.2kw at a minimum.

------author replies --------
OK, good point - perhaps I should have said "European households"

That's not a real rig, it's just a Photoshop mockup. The kites in it are kiteboarding/kitesurfing kites, and wouldn't be suitable for what they're doing. In their video they're also using a kiteboarding kite, though a different style.

... or one American home.

@Dallas

The kites don't need to be pulled downward against the wind by -- the kite shape and angle into the wind can be modified with much less energy expended through control lines, which would allow the kite to dive down rather than be pulled down.

If the operator knows the kites well and can read the wind correctly - the downward dive can return some energy into a climbing maneuver.

The great thing about kite-based wind turbines is the sheer number of different ways they can created.

Here's a floating wind turbine from Magenn.

Here's a giant ground based turbine pulled around by kites from Kitegen.

Here's a tethered helicopter-like "kite" wind turbine from SkyWindPower.

Here's a wind dam created by flying a giant sail between mountains. It works by funneling the wind to a turbine.

And this last one isn't a kite, but who wouldn't be interested in hearing about a design for a one gigawatt maglev wind turbine?

The great thing about kite-based wind turbines is the sheer number of different ways they can created.

Here's a floating wind turbine from Magenn.

Here's a giant ground based turbine pulled around by kites from Kitegen.

Here's a tethered helicopter-like "kite" wind turbine from SkyWindPower.

Here's a wind dam created by flying a giant sail between mountains. It works by funneling the wind to a turbine.

And this last one isn't a kite, but who wouldn't be interested in hearing about a design for a one gigawatt maglev wind turbine?

Hmm, I can't get the comment to post with live links, so I'm going to remove them and try. Just cut and paste into your browser to go to the articles.

The great thing about kite-based wind turbines is the sheer number of different ways they can created.

Here's a floating wind turbine from Magenn.
www.magenn.com

Here's a giant ground based turbine pulled around by kites from Kitegen.
www.kitegen.com

Here's a tethered helicopter-like "kite" wind turbine from SkyWindPower.
skywindpower.com

Here's a wind dam created by flying a giant sail between mountains. It works by funneling the wind to a turbine.
ecotality.com/life/2007/11/08/wind-dam-looks-like-a-giant-spider-web-may-actually-be-built

And this last one isn't a kite, but who wouldn't be interested in hearing about a design for a one gigawatt maglev wind turbine?
www.treehugger.com/files/2007/07/colossal_magnet.php

@JSDreyer: The Maglev windturbine is most likely a plot to get money from naive investors. The aerodynamic design is primitive. Friction losses in standard wind turbines are already small, so no big advantage can be gained by the maglev principle.

Jet stream winds, eh? That would be an interesting system to see in operation, with the 15-20km cable rising into the sky. Seems like you'd need to use some very light, but high strength cable.