Why Kite Turbines
Channel: Windswept and Interesting Limited
Date: 2022-10-14

We're often asked to explain what goes on at Windswept and interesting Ltd
Well now you know
We make Kite Turbines
And this is the video all about why.

Script
Why make Kite Turbines?
We need to harvest wind energy in the most efficient way possible.

This requires sleek blades, to continuously sweep fast across the oncoming wind. 

That sounds like a wind turbine . . . But wind turbines have problems with efficiency as they scale. 
First let’s look at the structure. It’s a solid cantilever tower, on a massive reinforced concrete base. Basically – these turbines become much heavier and more wobbly as they grow. This weight gain happens faster than the power increases. The structures become less efficient as they grow because they use more material per power output.

As for the blade. Only the tip of a wind turbine blade is moving fast. The tip of a wind turbine is its most aerodynamically efficient part. The rest of the huge structure mostly exists just to push the blade tip into wind at height.

But wind turbines need to scale so that they can harvest the stronger more reliable winds at higher altitude to generate more power per land area used. 

Kite turbines are a new way to enable scaling and efficiency. Kite Turbines use less material, to fly continuously fast, through large areas, in stronger winds at high altitude, for more power output. 

The Kite Turbine is made of a network of kites. The structure of the kite network is kept in tension by the pressure of the wind. When structures work in tension they can use materials more efficiently because the materials align with the forces.

Kite Turbines operate like wind turbines. The kite blades fly a similar path to wind turbine blade tips. The spinning Kite turbine rotor converts wind energy to torque. The torque is transmitted along a shaft of tensile tethers, to turn a generator, and make electricity at ground level. 

Keeping the generator at ground level, and holding onto the rotor from ground level avoids needing to use a huge steel tower, and concrete foundation. The ground station has an anchor which screws into the ground. This significantly reduces the size of equipment needed to install a turbine. So you don’t even need a road to bring equipment to site.

The Kite Turbine rotor has a hollow axis, it has no blade roots, the blades don’t connect to a rigid hub. This means the blades fly more efficiently at large radius and avoid flying slowly in the centre. The shape of the rotor is maintained by aerodynamic and centripetal forces from auto-gyration as well as using a lightweight connecting ring for launch and flight stability.

The kite turbine rotors can be stacked upwards and concentrically. The large radius also means the number of blades can be increased efficiently. This modular method of scaling the designs maintains blade sizes appropriate for the most probable wind. This keeps the whole network structure very lightweight. 

If we made the kite sizes too large, they would require unrealistically high winds and they would be inefficient and difficult to fly. But by networking ideal size blades we can scale a kite turbine deployment of hundreds of blades, potentially to huge sizes. 

This same pattern of structures growing and then changing to tension based designs happened in bridges and stadiums.
Tensioned designs align materials with forces to make very efficient structures.



Lightweight construction has the benefit of being cheaper, but more importantly having less embodied carbon, so Kite Turbines are cleaner and cost less to build. 
They are also easy to transport, deploy, take down, service at ground level and redeploy.

So far, we have only tested small systems, but our models and test results show that Kite Turbines should be able to take advantage of the better wind resource at high altitudes. At only 500m above ground, the wind over mainland Europe is as powerful as North Sea wind at 100m. 

We flew 70 prototype variations on only a household budget. And yet we achieved an astonishing - over 800W of electrical power output per kg airborne. 

We still have a lot of scope for improvement. 
We’re now working on automated deployment and more stable generation controls to enhance safety and reliability. We also intend to perform further study of offshore suitability. 

This next phase needs funding,  so we have now partnered with Shell GameChanger, HIE and Shetland Islands Council – you can join in too - get in touch if you have a hefty clean energy research budget
Or
You can build one of our old models using the guides on Hackaday 
Or 
Just be in touch, chat, share like etc.

Thanks

This is why we are developing Kite Turbines.

Find out more at our website https://windswept.energy

Extra video clips in video from 
https://youtu.be/t3alWwOsF3I
https://youtu.be/xNIxttcDhks
https://youtu.be/lKFi8IhVvRg
https://youtu.be/rHkWMQMECZ0
https://youtu.be/E9OGeiAu1g4
https://youtu.be/_anVJoFUCtk
https://youtu.be/oOZD77P0gSI
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