The Isle of Lewis is the largest of the Scottish Outer Hebrides, sitting in the North Atlantic off the west coast of the Scottish mainland. It is the first landfall after thousands of miles of ocean for a continuous stream of Atlantic weather systems, so as you might imagine it is a place in which there is no shortage of wind.
It is thus the perfect situation for a wind power startup, and in the aptly-named Windswept and Interesting Ltd it has one that is pushing the boundaries. Their speciality is the generation of power from spinning kites, arrays of kites that transmit power to a ground-based generator through the rotation of their lines, and because they release their designs as open source they are of extra interest to us.
Of course, if you are a seasoned reader you’ll now be complaining that we’ve covered this story before when they had an entry in the 2014 Hackaday Prize, so what’s new? The answer is that the 2014 story was a much earlier iteration than their current multi-level kite array, and that they have now reached the point of bringing their products to market. You can buy one of their prototypes right now, and there is a soon-to-be-launched crowdfunding campaign for their latest model. It’s not exactly cheap, but this first product is the result of 5 years of product development, and it is pretty obvious that more is on the way. For any open hardware startup to stay afloat that long is an impressive achievement, to do so in a field in which you are not surrounded by a huge supporting industry in the way for example electronics startups are is nothing short of amazing.
If you would like to have a go at building one of their spinning kites, you can do so with full instructions released under a Creative Commons licence, but for non kite builders their website is a fascinating read in its own right. Their YouTube channel in particular has a wealth of videos of previous tests as well as design iterations, and is one on which many readers will linger for a while. Below the break we’ve put one of their most recent, a montage showing the kite evolution over the years.
Our 2014 story complete with bicycle frame wheel support can be found here, but this isn’t the first similar kite we’ve covered. We showed you a circular aerofoil kite earlier this year, as well as a Swiss research project in the field.
I don’t see this scaling very well. Imagine a 100′ diameter version: the blades would need to be something a lot more substantial and massive, and it uses a steel cable to transmit the power, and then you have the problem of what happens when it comes crashing down. The other alternative – having the sky littered with thousands of these – is even less attractive.
That’s it. These types of aerial generating platforms would need to meet the same technical standards as commercial aviation, including inspection and maintenance schedules which would increase costs substantially.
This is not ment to scale big in size, but in numbers. The only problem I see here is lack of wind, what happens if the kite is down, and the maintenance of all the moving parts in bad weather conditions, maybe offshore?
Soft kites scale really well. They work in tension. Also use dyneema (R) line 8xstronger than steel and floats
Sure, there was speed, but was there any torque?
I imagine it would just twist the cables as soon as you put a real load on it.
There are 2 critical ratios to balance for torsion transfer, the cylinder ratio and tensile torsion ratio..
e.g. the stack will FAIL if you have a long distance between small rings (cylinder ratio part) and loads of torsion with low line tension (tensile torsion ratio part)
The stack will work ACE using a short distance between wide rings to transmit little torsion using lots of line tension.
Neither of these states would be optimal.
I couldn’t see any notes on the applications of these kites; are they intending them to be serious contenders/alternatives to large scale commercial generators?
I got the feeling they were meant for small scale applications, small holdings maybe, campers even. I’m not expecting a skyline full of these anytime soon supplying power to the nation (though, I’d argue, that would look darn cool compared to pretty much any other option :))
Love the ‘directions’ on their website (really demonstrating the size of the island)
He has a video of this kite running over 100w (some 100x100x100 challenge where it needs to be 100w for 100 minutes at 100ft) so it looks pretty good, just have to see how well these things scale.
I like the idea how will it get better unless we try, every thing starts small when did y’all ever bild something new and it worked 100% perfectly and had no compromise I can’t think of one invention are creation but if we keep working at it it could be the next big thing. electric light who needs it we have candels they can break and cut are shock and kill you there dangerously
This is a splendid machine, but speaking as a Scot, wind power can’t be the answer to everything. Here for the last eight days there has been not a breath of wind, but it has been freezing cold for seven of those days – conditions in which demand for electricity is high but wind turbines sit idle.
Freezing cold you say, then build a Thermoelectric generator, about 30 feet under the ground the temperature is close to constant all year round.
With a thermal conductivity of around 1.5 W/m K for silica, you’re gonna saturate the grounds heat capacity rather quickly.
Here in Germany they’re are currently testing several storage methods for excess wind power:
Power to Gas (/ Gas to Power; Hydrogen generation)
Stationary flow cell storage (in contrast to cars: size and weight doesn’t matter, which is a big advantage)
Thermal storage for daily fluctuations (Heating of an insulated stone reservoir to 600C and recycling the heat energy with a steam turbine (currently under construction by Siemens)).
We’ll see which storage method will succeed…
It’s not just the lack of wind on occasion. Sometimes there’s far too much.
As a local fisherman in Port Ellen said to me when I inquired as to the fate of the wind turbine which had been constructed nearby with a great fanfare and funding from some idiot in Brussels.
“Och, it just blew away one night last winter.”
Even the massive concrete base is now gone. Washed away in another winter storm a couple of years later.
Yep, too much power is the killer in all wind turbines. Tower devices have a HUGE bending moment to overcome. and weight to lift. Kites are aligned with tension. Cubic mass scaling means a 2x height tower = 8x mass. So the EROEI (Energy Return on Energy Invested) becomes dreadful. Power available with wind varies with cube of wind speed. High altitude = high speed. “Soft” kites have really good feathering, loose leach, depower and even furling modes available to designers. And the centripetal acceleration isn’t going to tear them apart unlike heavy blades. I’m still coming down for storms and lulls (Or cheap & easy service time as I see it. can’t do that on a tower) Kite service life is expected to be over a year, but replacements are cheap so Levelised Cost of Energy is low. Kites work in tides too… see minesto
More COAL
Wat? Santa says you’re getting half of Pennsylvania in your stocking as it is. ;-)
Only half?
What is this guy Santa? some sort of Communist?
Make Scotland great again! Wait a minute, it already IS great!
How long would that last before it started to fall apart 6 months?
Six months is what I would think too, falling apart from wear over the winter and falling apart from UV damage over the summer. However, if I needed a small wind generator, I would choose this design because the bloody three bladed propellers on the end of a stick are boring, boring, boring – I’d die from sheer boredom with those.
Yeah, while I agree they are boring and slightly annoying, you can decrease the boredom by watching videos on your fully charged tablet, while you neighbours get more annoyed by your free electricity, right up until the wind stops, then it excelles in it’s capacity to bore and annoy all at the same time.
Ever heard of a battery and overhead?
Hi, Rod from windswept and Interesting, Thanks for the article… wow cool.
Yeah the videos show the kite takes a kicking when testing turns into learning.
It has been a hard slog, but so worth it.
This all stems from an interest in the science of Airborne Wind Energy Systems. It’s an actual thing. Loads of boffins, nerds, geeks, and all round good dudes way smarter than me are into it and I recommend it.
Only suitable for explorers and my PhD student in the current form.The last model was running over 300W. The next model is going to be a lot simpler to rig and is expected to sit ~500W.
These are small models, on very short stacks. 3 x 3 kite rings.
Soft kite network architecture is all about scale-ability. I’ve been messing with kite lattice patterns and testing the behaviour of networks of soft lifting kites. They can be the biggest things we’ve ever built, No question.
I’ve been looking into the dynamics of the tensile torsion transfer. There are 2 critical ratios to balance, the cylinder ratio and tensile torsion ratio..
e.g. the stack will FAIL if you have a long distance between small rings (cylinder part) and loads of torsion with low line tension (tensile torsion part)
The stack will work ACE if a short distance between wide rings is used to transmit little torsion using lots of line tension.
Neither of these states would be optimal.
This all stems from an interest in the science of Airborne Wind Energy Systems. It’s an actual thing. Loads of boffins, nerds, geeks, and all round good dudes way smarter than me are into it and I recommend it.
Only suitable for explorers and my PhD student in the current form.The last model was running over 300W. The next model is going to be a lot simpler to rig and is expected to sit ~500W.
These are small models, on very short stacks. 3 x 3 kite rings.
Soft kite network architecture is all about scale-ability. I’ve been messing with kite lattice patterns and testing the behaviour of networks of soft lifting kites. They can be the biggest things we’ve ever built, No question.
I’ve been looking into the dynamics of the tensile torsion transfer. There are 2 critical ratios to balance, the cylinder ratio and tensile torsion ratio..
e.g. the stack will FAIL if you have a long distance between small rings (cylinder part) and loads of torsion with low line tension (tensile torsion part)
The stack will work ACE if a short distance between wide rings is used to transmit little torsion using lots of line tension.
Neither of these states would be optimal.
Uhh woops. must learn keyboard 101