Kitegen High Altitude Wind Power - Very Clever Idea IMO

MitchJi

MitchJi

10 MW
Joined
Jun 2, 2008
Messages
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Location
Marin County California
Hi,

Very Clever Idea. Seems like a perfect compliment to Solar Thermal.

Main disadvantage appears to be that it requires a no fly zone but:
http://www.kitegen.com/en/technology/details/
To help visualizing the existing unexploited potential, just consider that the flight prohibited area over a nuclear power plant can easily get to contain 1 GW of wind power, equal to the power of the plant itself.
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From their FAQ:
http://www.kitegen.com/en/technology/faq/
What is the cost of the energy produced by a Kite Gen power plant?
A 100 MW Carousel power plant is estimated to deliver energy for less than 0.03 Euro per kWh, which is cheaper than fossil fuel-based generation. Even lower costs are to be expected from bigger and more powerful plants. In the Stem configuration the foreseen cost is around 0.05 € per kWh

How does wind power change with altitude?
As altitude increases, average wind speed increases (and remember that wind power grows with the cube of wind speed) and air density decreases. Wind power decreases linearly with air density, but even at 1000 m air density is reduced by only about 10%. Wind power therefore always tends to grow from ground up to approx. 10,000 m of altitude.

The following video shows how the Stem generator works:
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[youtube]Zl_tqnsN_Tc[/youtube]

Two Styles (Stem/Stem Offshore and Carousel [they are working on Carousel Offshore ]):
http://www.kitegen.com/en/products/stem/
Kite Gen Stem
In the “Stem” configuration the wings pull the cables that, through a pulley system, activate the alternators on ground, that produce electricity. When cables are entirely unwound, the wing is guided to a position where it loses its wind resistance and the cables are wound in. Energy consumption of the winding phase is a minor fraction of the energy generated during the unwinding phase...

In 2006 Kite Gen Research has built a first prototype, codename KSU1, tested at an altitude of 800m with the authorization of ENAC and ENAV (Italian Civil Aviation Authorities)...

eyond the verification of the theoretical data, the KSU has produced energy, thanks to the unwind/rewind cycle: 5kW average and 30kW peak, with a ground of 4.5 m/s.

Stem configuration has been producing today and functioning of the first generator, near Asti – a place where wind conditions are considered to be definitely inadequate to traditional wind generators – is foreseen for the end of 2009.
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http://www.kitegen.com/en/products/kite-gen-stem-off-shore/
Kite Gen Stem Off-shore
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http://www.kitegen.com/en/products/kite-gen-carousel/
Kite Gen Carousel
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carousel.jpg

The configuration combines a series of Kite Gen generators, considered as a “base” module, where the tension in the cables is maintained constant and their length changes only to grant the wings control, in order to obtain the optimal trajectories for energy generation.

As the power kites circle in the air, at an altitude of 800 – 1000m, the vertical rotating axis of the structure activates large scale alternators, that have been geared down to receive the force exerted on them. At its full capacity the flight of the entire power kites array is guided, so as to turn the carousel at the desired speed, with a capacity factor estimated at 5,000 hours per year.

Maximum reachable size is under study, but first evaluations shows that 1,000 MW (1GW) can be exceeded, without significant structural risks, with a diameter of approximately 1,600m.
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Looks cool. The airspace used up would be a problem in a city of course, where air traffic is all closer to the ground to land and take off. It wouldn't bother jets any at cruising altitude, and in some places there is already some big areas where flight is prohibited anyway. NM is a good example, with the White Sands Test Facilty that covers a huge section of the state. So out here in the sticks we wouldn't have much problem with avoiding the airspace any more than we do now with military airspace or things like the thethered radar blimps all along the border.

There'd still be the ol bird issue though, and they might have trouble avoiding the kite lines more than they currently do with fan blades. So some sensitive areas might need avoiding, such as right next to a major flyway or refuge.
 
Hi,

Until I watched the video (from about 0:20 to about 1:30) I wasn't sure how it works.
 
This would be a good add-on for cargo ships equipped with kites. If it could dampen the loads placed on the structural components by the odd strong gusts you could increase kite size without increasing the max stress seen by the thing. Not to mention the electricity for the ship.
 
Hi,

vanilla ice said:
This would be a good add-on for cargo ships equipped with kites.
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You mean in addition the Kites used to propel the ship?:
http://www.treehugger.com/files/2008/03/beluga-skysails-cargo-ship-kites.php
beluga-skysails-kites-002.jpg

At the end of January, we wrote about the Beluga Skysails, a commercial cargo ship that was testing the use of giant kites as auxiliary power - a kind of hybrid wind/fossil-fuels system.

We're pleased to learn that the Beluga Skysails trip was successful: The ship set sail (literally) to Venezuela from Germany on January 22nd and reached the Norwegian port of Mo-I-Rana on March 13th after traveling a total of 11,952 nautical miles. "In even moderate winds, the first flights of an initial 160-square-meter towing kite propulsion system from the Hamburg-based manufacturer SkySails demonstrated how this innovative auxiliary propulsion system was able to substitute for 20% of the engine’s power." After the pilot phase, the towing kite will be replaced by one that is twice the size, providing twice as much energy and saving twice the fuel (which could mean $2000/day)...
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I think this is similar to the kites for ships, but adapted for generation. It comes from the kitesurfing kites which fly a figure 8 pattern to increase the pull, similar to how a regular windsurfer can pump the sail. This produces a pull and let off on the kite rope, that could be used to turn a crank or in some other way, convert to rotation for a generator.

The kites are incredibly powerfull. Ive seen some guys learning how get dragged 1/4 mile across the beach when they screw up with a very small training kite.

Another good approach may be captive balloons like the radar ones on the border, but with generators on them. As a balloonist, I'm well aware that upper wind is much stronger than ground wind. This is why we only fly in the early morning, when those stronger winds are higher than we fly.
 
Well what I meant was the generator base portion would be a good add on for the ship kites. Light winds would push the ship without drawing the line out. Strong gusts would pull the line out without increasing the max pull force experienced by the line/kite/ship beyond the average wind force, and in this way dampen the forces on the whole apparatus. So with the dampening, at least in my mind, you would be able get a higher average force for the ship by having a larger kite area for a given construction method/materials. Plus maybe you could have a small electric pod prop, or simply take the alternator load off the engines.

Maybe not though... They probably have a sophisticated dampening system on those ship kites already.
 
Hi,

Video Here
The first stage increases the relative flow speed entering a turbine. When the tide hits the wing it creates a lift force, since the kite is mounted to the ocean bed with a tether and is controlled by a rudder, the kite can be taken in the desired trajectory, here in an eight formed path. The method increases the flow velocity into the turbine by 10 times, compared to the actual stream velocity.
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deep_green.jpg


http://cleantechnica.com/2009/10/23/underwater-kite-harnesses-ocean-energy/
Underwater Kite Harnesses Ocean Energy

A completely new concept of underwater wave energy using a simple 7 ton kite turbine design has been developed by Minesto; which is a spinoff from the Swedish military and aircraft design firm Saab. The Deep Green underwater turbine captures the power of the ocean just like a kite in wind.

The system could generate 18 terawatthours of energy annually, enough to provide nearly 4 million British households with reliably green electricity every year. UK households now use about a third of what average US households use in energy.

Originally Saab was working on a kite design for a wind turbine, but found that the concept would actually work better in water, which is 832 times more dense than air.

The kite twirls in a repeating figure eight pattern that increases the ocean velocity ten-fold. The first stage increases the relative flow speed entering a turbine. When the tide hits the wing it turns down, which creates a lift force. The kite is mounted to the ocean bed with a tether and is controlled by a rudder to gently nudge it in the desired trajectory.

According to Minesto’s website, each megawatt-worth of kite(s) would weigh 14 tons, so it would seem that each 7 ton kite is a 500 KW unit. According to CEO Anders Jansson’s estimate, these could probably produce power for somewhere between $0.09 cents and $0.20 cents per kwh.

Certainly because these are such extremely simple-tech structures they would be cost effective - costing less in materials per power produced, and costing less in transporting them to the site, in installing them and even in ongoing maintenance costs.

Almost half the potential in Europe is in British waters, with the ocean moving an average of 1 to 2 metres per second between 60 and 120 metres below the surface.

The Carbon Trust based in the UK gave early development support. Minesto’s Deep Green is now funded in part by the UK and Swedish governments, and has nearly $3 million in additional capital from parent company Saab Group, Midroc New Technology, Verdane Capital and Encubator.

With these kinds of serious investors, and such a simple and cost effective design, this could be what gets wave power to the world.
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I wonder how they manage to get a durable electric conductor that can last many years submerged in salt water, with barnacles growing on it etc.

The resistance of the cable/conductor under water might be a massive problem.

Also, whales and big fish might not be able to avoid the cables and/or the generator.

The accumulation of massive amounts of plastic bags on the cables could also pose a problem.

The whole thing is a brilliant idea, both in air and in water.

Starting the kite might well be the hardest part; and avoiding of any crash landings or landings on it's nose when the wind stops or the tide turns.

Even if it crashes just once a year under water, it might be too expensive to repair/refloat.

Lot's of interesting challenges there!

How long will it take before the moon falls down if we become proficient at extracting tidal energy?
 
Mr. Mik said:
I wonder how they manage to get a durable electric conductor that can last many years submerged in salt water, with barnacles growing on it etc.
The resistance of the cable/conductor under water might be a massive problem.
Click to expand...
Blimp generation has similar issues: long conductors, high voltage wires in the air, etc. The kite design is better than LTA, since the generation is done at the ground.
 
Everything seems to lead back to solar heat energy,
for all the tides' power and winds, unreliable, a great deal of the world
is constantly warmed by forever predictable solar heat.

And it seems liable that using that heat, translated into water (high latent heat)
and then drawing the energy out of the water (say, a covered pool of sorts, kid/idiot safe)
would provide plenty of efficiency and such to drive, say, a large-ish stirling engine,
and gain higher power outputs, even, than solar power panels, which only work when the sun shines.

And a solar water system at least contains the energy (buffers it, as do secondary batteries.)

Wind kites and tidal force kites might not work well here in the Miami area, but tell you what:
the low-tech solar water heater system, thermosyphon, that our 1937 Almeria Ave. house had atop its flat roof portion,
was not that big, and provided forty or more years worth of totally free hot water for showering a family even of five,
hot showers for almost as long as you like, and rarely was the "booster" electric element needed. Just big storage (buffer) tank,
and a good deal of copper pipe (they used then), some two by four foot, by six inch deep black-insided collector boxes,
and...

The brick courtyard pavement here is brown. In mid summer the surface temperature reaches 160F.
It stays hot for a long time. Have heard that our solar energy per square yard in summer is on the order of over one horsepower.

Solar is viable, perhaps, for much small, domestic power production. The newer Stirlings work well with hot water, more efficiently than
solar panels, I think. Have an empty swimming pool. Could be converted by next owner (covered over) to be a huge reservoir for house-powering energy,

also good for great lobster boiling sessions.
 
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