[dietlbomb]

I see stories promoting kite energy harvesting every couple years. They never address (one of) the primary obstacles to a functional unit: transmitting the energy to the ground. They usually hand wave the problem by saying there will be a conductive tether, but they don't mention the challenge in designing a tether that is strong enough to hold the kite, while also conductive enough to transfer power, while light enough for the kite to stay airborne. The usual solution for ground based power transmission it to use a high voltage, but that requires significant insulation separating the conductors, usually air. Other materials tend to fail under high voltage. So they will be limited in maximum voltage, and be forced to have a larger diameter conductor. It would be too heavy and won't fly. Tldr; this is probably a scam.

[Grustaf]

A scam? That's one elaborate scam! I mean you have some 40 organisations around the world working on kite energy, including Google X and several leading universities. It's almost like it would be more impressive if it actually were a scam. But it's not of course.

As to the tether, people are of course aware of the requirements it needs to fulfil, you can even find calculations about it online. Making it strong enough and still light is not a problem, the challenge is really in combining a structural tether with a conducting cable. It is a challenge, true, but it's far from impossible and there are several possible designs.

Makani's 600 kW prototype: https://www.youtube.com/watch?v=An8vtD1FDqs

[Houshalter]

Bad ideas often get funding and support from prestigious seeming institutions. Look at the stupid waterseer thing: https://www.youtube.com/watch?v=LVsqIjAeeXw

[timthorn]

The electricity can be generated on the ground, so you only need to have low-power links in the tether for controlling the kite dynamics.

[bigohms]

That is not what the illustrations show in this model. Electricity is generated at the node of each wing and transmitted down link.

[timthorn]

Indeed, and both models are in development by different groups. I was responding to dietlbomb's comment that kite power proponents "never address" the problem of power transmission in the tether.