My name is Andy Snell, I'm the chief technology officer at RIDLID. Our mission is energy for sustainable civilizations, so we're all deeply troubled in this room about the fact that we really don't have a line of sight with sustainable civilizations. Really, our goal is to move that direction. The picture is there with our team of a roughly 4 square meter FlyGen kind of a system

that is targeted for our first customer in the U.S. military whose been funding our efforts so far. Taking some of that learning, thinking about scaling up as we've been talking about what a FlyGen system looks like as it gets larger.

A little bit more of a technical approach to this, but really what I'm going to talk about is what is the right scale for an airborne wind energy system, particularly a FlyGen system. So to start out with, since we're talking about scaling, thinking about human beings, like what does a human being look like? If I'm a length scale of one, what is a quarter scale human being?

Anybody guess? How old? It's a newborn. Half scale? Anybody have a guess? Anybody break? Yeah, two and a half year old. So we don't think about length scale in the way that, wow, two and a half year old is a half scale.

So we've talked about going, I'm going to go double my scale. That's a really, really big deal. NBA players, a one and a quarter scale. And then Robert Wadlow, who's next to his normal sized father, is the end of the road for human beings. One and a half, just over one and a half. He died at a young age, scaling in my view.

So human beings only exist in a fairly narrow range, and the question that we wanted to address is, as we think forward, how do we address this challenge? Are there limits to scaling, also in airborne wind energy? Or do things scale up nicely? So we kind of went back to first principles a little bit.

Sorry about the pounds. You can see the humans don't actually scale a square cube. They're about 2.4. I'm not exactly sure why. But a square cube is sort of the rule in nature, I think.

Our outline of this study, we're really trying to make a sensitivity analysis, going back to sort of first principles. How does the system scale versus the fitness parameters we'll talk about in a moment. As I mentioned, we're just flicking a flag in systems. We didn't consider launch land, although that's definitely a consideration. What we used is an internally developed tool called OZOP,

which is a lump parameter tool that produces output like this. It's just sort of a random data point for an optimized cycle. You can see power going out in the green. That's the good stuff. The red stuff, the bad stuff. We've got to put a little bit of power in in this particular cycle to make the upswing.

And that's that one. I'm sorry, I'm flying an up loop there. So just real first principles. What does this look like as things get bigger? System fitness. We've done lots of detailed models about LCOE, but in this particular context, what we're going to try to do is keep it really, really simple and say we're looking for specific energy,

watt hours per kilogram of the flying system, which we're defining as a plane plus tether. So it's a premise. It's an assumption. If a system uses more material to produce less energy, it's probably not a good thing. The subject is some assumptions. The way the flying system in a tether is a reasonable proxy

for your generation cost. The capital cost is just that part of the system. And then the whole series of things, logistics, installation, O&M, NRE, are not sensitive to scale, which are variously not true, but at least it's a starting point. And then you've got externalities, such as wildlife interactions,

ocean use that are also not sensitive to scale. So if you make those kind of basic assumptions, then you can say, I want to get the most watt hours out of the least kilograms. Sensible starting point. So some basic assumptions. We call our length scale one,

something we know the most about. So our four meter squared system weighs about 60 kilograms. A lot of technical assumptions there, which I don't want to read to you, but are certainly there if there are any questions later. Some basic assumptions on the tether. The power system is a fly pen system, so we're looking at voltage ranges there,

a tether length, which we did optimize, but you can, it just takes time. Just pick sort of a nominal number there. And in a tether model, we're actually scaling the way we think it needs to be scaled, although it wouldn't hold us out as complete experts in tether design. That's what we're doing.

We're not scaling that square cube, for example. We're scaling that the way it looks like it needs to scale to get power up and down. As far as the power system, there's some details there. Just trying to document sort of at a lower level where all this stuff comes from. So scaling.

I don't know if anybody's familiar with this great flight diagram. It's actually updated a little bit with some folks that are working on some sail planes out of this paper that I found. Effectively, interestingly, from NATS to 747s, the square cube scaling, which is the main line there, is how the world works. It's difficult to, it's interesting, quite interesting to see

that that line just goes up into the right. And if you were looking, you know, the best possible case would really be what I guess you could call square-square scaling, where your mass would go with area. That would show up as a vertical line on this chart, and it's a little bit difficult to see, but there aren't really any vertical lines

or very limited vertical lines in nature. It makes sense. Square cube is probably your starting point assumption for how things are going to scale, if you don't know anything else. We did, however, look at three mass scaling factors. Square cube is the first one, and then something intermediate.

And then just as a lower bound, really, if they scale square-square, so they scale the mass of the flying vehicle scale to area. And something I wanted to just drop into just a little bit, and I don't understand these very well, but this was sort of the red line

down in the lower left of that box and all these cluster of lines which all represent snowflakes. Those are worse than square cube. So I don't understand that. If somebody else does, let me know. But I just thought it was useful to point out to the group, square cube isn't necessarily the worst case, and it's a really big assumption.

Basic assumptions are calculation methodology. We looked at a very specific wind environment with a viable K-value of two, fairly good wind regime, 90 meters per second at 90 meters, and a wind shear exponent of 0.11. I think we're very much feeling like the offshore environment

is where these things come from. We'll want to live eventually, so that's sort of a good offshore site, I think. Maybe not great, but certainly achievable. When we talk about power, we're certainly talking about net cycle electrical power, taking into account everything. So there's all kinds of powers.

We try not to say power. It's too generic. But in terms of this discussion, net power output is actual useful energy down the tether. So all the calculations that we did take into account the viable distribution, the actual energy that will be output out of the system.

So this is kind of the graph here. Starting at the left, our scale of one, as I mentioned, is our four meter squared system. And what we see is the top line is what we call it square squared. That would be where the flight vehicle is scaling.

Linearly in mass with area. And you see it gets a little bit better going from that four meters squared out to, let's say, two, it looks like. So that would be 16 meters squared. So there's still fairly small systems relative to some of the targets that we've discussed today. And then it starts tailing off.

And this is taking into account really everything in terms of the scale three has access to the wind at three times altitude. But it's still not performing better. Square cubed fairly rapidly, just down to the right.

These mass effects are ideal for kites, which we all know. These are difficult effects to model. Our OSOT system is pretty good. It really made an effort to try to optimize everything. But you can see that watt hours per kilogram, if we believe that's the fitness factory, we're there right now, maybe,

right at scale that I showed at the beginning. And we're doing nothing but getting worse by making things bigger. If you believe square cubed is where we're going. So that's sort of a sobering thing, right? So you've got to find reasons to go bigger that don't involve the system

to go outside the system. So you kind of revisit some of those assumptions that costs are not sensitive to scale. It seems a bit counterintuitive to say that a 1600 kilowatt system is the right size. But maybe it is, and that's something that we've spent a lot of time thinking about.

One other thing I would note, that bottom line there, onshore wind, it's about 30 kilowatt hours per kilogram. So we're talking not quite two orders of magnitude difference from that to sort of an optimal system in our analysis.

So it's a big difference. And that is to say that even a square key scaling fly pen system at a scale of three, which is kind of a little shy of a 600 scale, is still a lot better than a wind turbine, just on that metric, it's a lot better.

So this is one of these things that we've talked about in a very simple chart, but if we look at the rated power of the smallest saleable unit of a technology, and we include solar. Solar is right now, say, $45 a megawatt hour.

They're putting 0.2 kilowatt modules in. That's how they're doing this, right? Just do a thousand of them, and at the same time, at least they can do it effectively. As effectively as a wind system, it's a two megawatt, right? So that's put a thousand in, pick up a thousand things, pull a thousand things in, wire a thousand things in,

and they can do that as cost-effectively, probably more cost-effectively as time goes on, than wind energy, right, that exists today. So if 100 kilowatts is a system that we usually would think about in the air, when wind energy is saying, well, that couldn't possibly be the right scale,

because wind, you know, gotta be three megawatts. If you're offshore, it's, you know, we're headed to 10, 12 megawatts. I'm just not sure if that's the best assumption. I don't know if there are, there are definitely challenges with having a smaller system, but there are also nice things coming up on my time here.

So, this is really an ugly slide, I apologize, but I just wanted to go through assumptions that you would make. Capital cost of the APG and tether can be approximated by weight. That feels like, I won't call it a no-brainer, but if you gotta put more stuff in, you gotta buy more stuff, you gotta hand more stuff,

ship more stuff, you ought to use the least amount of truth you can in your flying system. So, that feels right. If we get back to the things that I've later read, that might invalidate some of these things, or more studies really needed. The ground station anchoring interconnects, we're talking about offshore systems,

are certainly an area where you can make an argument that a larger scale is going to be better. I don't know that that's an ironclad argument, but I would say that with the difficulty associated with scaling these systems up, that might be an area that people would look into a little bit closer and challenge that assumption, is it possible to make an airborne wind energy system at sort of a medium scale and still make it cost-effective,

because it looks like that maybe where these things want to live, at least for a flying system. So, summary, generally we see very little improvements associated with scaling, even in what we consider to be sort of small scale, so we have a wind energy world,

and on this bit, this parameter gets worse as we get bigger. Lots of assumptions. I'll leave it at that, because I'm getting a sense that I'm at the end of my time. I'm happy to answer any questions.