Alternative Energy

Alternative Energy

Alternative energy news, and information about renewable energy technologies.

May 20

Harnessing High Winds With Giant Kites

Posted in Energy Inventions | Future Technology | Wind Power

Giant Kite People are trying various sources to produce alternative energy. We have often witnessed children flying kites. But very few of us have given a thought to generate energy from kites. Scientists from Delft University of Technology in the Netherlands produced energy from the wind by flying a 10-sq metre kite that is attached to a generator. It generated 10 kilowatts of power. This energy was enough to meet the power needs of 10 family houses. Scientists are now aiming for a 50kW version of their invention. They have named it Laddermill. Their ultimate aim is to go for a version of multiple kites. They will be able to produce 100 megawatts of power that could meet up the energy requirements of 100,000 homes. In order to generate power the kite pulls a string attached to the generators on the ground. Upon reaching their maximum height, they are reeled back down to repeat the process.


Wubbo Ockels, who is the professor of sustainable engineering and also a former astronaut, is leading the Laddermill project. “We need to use all the energy supplies that are offered to us by nature, we need diversity and kites are … intriguing and fascinating.” He explained that kites are a cheap way to reap the vast amount of energy available in the wind at a kilometer or more above the ground. It should be noted that winds carry hundreds of times more energy beyond one km or more above the ground than on the ground.

Google.org, which is the philanthropic wing of the California-based web-search company, agrees with Wubbo Ockels. Google.org spent $10m (about £5m) last year on a US kite company called Makani. Google.org has committed itself to invest and encourage the organization’s Renewable Energy Cheaper than Coal program.

Both of the above organizations are aspiring to avail the high-altitude wind. Tapping wind at considerable height is beneficial in many ways. First, it is the energy source that is more abundant than ground level wind. Wind at high altitude is dependable too. Speed of the wind at considerable height is more assured than ground-level wind which normal turbines depend on. Ken Caldeira, who is a climate scientist at Stanford University’s Carnegie Institution, has projected that the total energy contained in wind is 100 times the amount needed by everyone on the planet and most of it is available a higher altitude.

As we know, the blades of average windmills are situated about 80 meters from the ground. At that height normally the wind speed is five meters per second. But if we go higher say at 800 meters, wind speed is seven meters per second. More speed means more energy. Till now we don’t have a technique to place wind turbines at the height of 800 meters to generate more energy. But we can easily use kites at that height.

European countries such as UK, the Netherlands, Ireland and Denmark have another advantage too. They fall in the high stream jet area that is ideal for flying kites. Allister Furey of the University of Sussex is involved in developing computer control mechanisms that suggest ways to maximize the power generated from kites. Allister Furey said about the advantages of the kite energy, “Pretty much anywhere in the UK you could run a kite plant economically, but you couldn’t run a wind turbine economically.”

Furey’s computer models have established that flying kites in a figure 8 pattern means the air flowing over them travels even faster than the surrounding wind velocity. When a kite is reeled in, it falls out of the sky like a glider, without the need for much power. This way the kites can generate maximum power. He is considering applying the same prototype on multiple kites that behave like a yo-yo; when one kites comes down, another goes up. Ockels estimates that kites could generate power at less than 4p per kilowatt-hour, which is comparable to coal power and less than half the cost of electricity from wind turbines.

Furey explained further, “The first systems will be community scale that could power a large farm and sell some electricity back to the grid. Once the technical issues have been sorted out, you can scale them up to the level of a coal-fired plant. All you have to do is multiply the number of kites and you can have a farm as big as you want.”

Kitegen, an Italian company, has quite ambitious plan come regarding energy generated from flying kites. They are developing a theoretical paradigm for a system that could produce a gigawatt of energy. A normal coal-fired power plant produces that amount of energy. They think that flying 12 sets of lines with four 500-sq metre kites on each will be sufficient to achieve the target.

Nick Rau, an energy campaigner at Friends of the Earth, shared his views, “We could easily supply our electricity demand from offshore, even with other demands on sea such as shipping, fishing and defense radar. These new [kite] technologies allow us to go further offshore and avoid other problems. We have an abundance of renewable energy and there are a lot of visionary technologies coming along so that, in future, the sky’s the limit.”

  • Robin Seller

    Such creative minds! You need to devise some sort of coil spring that pulls it back down to a certain point to get that yo-yo effect for perpetual motion. How awesome!

  • Bman

    This sounds cool, but how much energy is required to pull it back down? This seems somewhat counter productive to repeatedly use energy to generate energy.

    What about utilize balloon technology? Mount a light wind turbine to a balloon connected to fiber optic cable and leave it aloft for long periods. Maybe a solar cell could be mounted to the top of the balloon too, generating a small amount of solar energy to power a little gas mechanism that periodically added gas to the balloon over time.

    Is this crazy?

  • Arun

    This sounds “The” great idea! So, my question is; why is it not possible to implement kitegen in Urban areas like Cities. Since cities are already heating up and there temperature is above 40 c and due to heating within built spaces, air tend to be lighter and moves up creating supportive place for Kites to fly in the sky. Can we augment kitgen on individual houses??? would be creative stuff as well!
    cheers
    Arun

  • Sarfraz Ahmad

    Quite a breakthrough….! I wish best of luck.

    As said Mr.Robin… Perpetual motion effect can help a lot. a step further you can also use the thin film Solar at the outer surface of the kite.

    Hope to see these kite flying higher in the sky.

  • http://www.jameswestwood.me Jimmy

    My reaction to this is exactly the same as Bman. Surely the amount of energy needed to reel the kite in is equal (or higher) than that generated by allowing it to fly skyward.

    Isn’t this the same as say, attaching generators on wheels that role down hills only to push them back up the hill to restart the process?

    Counterproductive?

    I must be missing something. Can anybody enlighten us?

  • matt peffly

    The idea is to steer them down. You apply a small amount of force to the guild strings to change the kites flight pattern. So you are not pulling them down, you are steering them down. Think of a para-glider, there are large strong lines that attach the glider to you and very small lines that you use to change the shape it’s shape and steer.

  • Kris Taylor

    I am just wondering how high of winds these kites can operate at. For example, I am looking for a wind technology for an area that can have winds up to 28 m/s. Would this technology be appropriate for an area such as this?

  • Dan Fann

    The Kite works like a gliding parachute all you had to do is have a servo pull some string to change the shape of the kite so it doesn’t create lift and as it dives down you reel it in. A little energy is used but not nearly as much as is created.

  • Jezreel Magbanua

    Airplanes and birds are in great danger. Some means of communication is needed here. I think the balloon idea is also good, just put some means of lowering it down with minimal power requirement. I hope this technology can be applied to the Philippines. We have a lot of mountains here.

  • Mike Maybury

    As a believer in non-violent defence, I wonder whether the idea could also act as a defence against hostile planes. In the UK, in the second world war, barrage balloons were raised around towns and other targets. Their wires provided a deterrent against planes.

    The lines from kites, I understand, would also move laterally and would be even more of a deterrent.

  • Euroflycars

    As a believer in the civilian society’s self-defense capacity — based on myriads of personal aircraft taking possession of the hitherto exclusively militarily controlled airspace — I have no doubt that the idea would act as an obstacle to such massively popularized individual aeromobility, i.e. to the transfer of individual highway road traffic into the global airspace as an indispensable prerequisite for the advent of the global village and world peace.

  • Euroflycars

    @Bman

    Since a balloon is floating in the air, there is no wind whatsoever around it.

    But you may be kidding us…

    Anyway, the biggest problem of a kite dedicated to this use is it’s tether line fixing it to the ground — unless all aircraft would be equipped with automatic radar detectors coupled to the autopilot in order to avoid the lines automatically.

    Yet this high-wind-harnessing kite technology is, alas, likely to benefit from government subsides for the sole purpose of building up still another obstacle against General Aviation…

  • Carlsongs

    I like this idea. But I am wondering how much energy it takes to reel the kite back? Also would you need a human to fly the kite? Why not use a balloon and attach wind turbines to it and a solar film on top


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