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Imagine a future where you look out the window and,
instead of smoke from a power plant,
you see multi-colored power balloons or kites
bobbing along above the countryside.
This is the bright, clean, wind-powered future of green energy
that some engineers are envisioning.
Not for sci-fi reasons,
but because it gets around a lot of the practical limitations of wind power.
The idea of putting wind turbines on kites or blimps is called airborne wind energy.
In this episode,
we’ll talk about why it’s cool
and why some people are blown away that it’s already being prototyped –
but also the challenges we’ll need to fix.
So if we’re going to talk about hypothetical airborne wind power,
it’d be good to start by talking about conventional wind energy.
Both since it shares a lot of the same tech,
and so that we can understand what problems airborne power might solve.
Conventional wind power works by putting a turbine in the way of some wind.
The wind pushes against the turbine’s blades,
causing them to spin, which in turn, spins an electrical generator.
And, technically speaking,
you could do this with any turbine, not just with the big fellas out there.
You could stick one onto the roof of your house or something.
There are even mini-turbines designed
to be placed near highways to collect wind from passing cars.
But how much power you get out of a wind turbine depends
on how big it is and how strong the wind is.
To get enough power to actually power a house or city,
we need to either build a lot of them,
build them bigger, or capture speedier winds.
This is where those big wind turbines come in.
Newly-built wind turbines are about 100 meters tall on land
and about 150 meters tall offshore,
which allows them to get to the more consistent winds
that occur higher above the ground.
But building these big things
comes with one big disadvantage:
their, well, big-ness.
Big turbines are expensive to build,
and use literal tonnes of carbon-intensive steel and concrete.
And as you can imagine,
it’s not exactly a breeze to install one of these things.
Furthermore, while taller turbines are able to get at stronger winds,
there are even better winds still beyond their reach.
Ironically, the turbines are both too big and not big enough.
But, okay, okay,
here’s where we get to talk about airborne energy
and why it could be clever.
Because, you don’t have to build an expensive, cumbersome tower
if you don’t have an expensive, cumbersome tower.
There are ultimately two basic versions of airborne wind energy.
The first is relatively straightforward.
You just ditch the tower and put the turbines
on a blimp, glider, or kite.
A set of cables could be used to reel it in or out,
with at least one cable also being used to send electricity down
from the turbines to the ground.
The second version also uses a kite or aircraft on a tether,
but doesn’t put the turbine on the aircraft.
Instead,
we rely on the pull on the cable for the oomph.
In this case, we leave the turbine on the ground,
and the kite’s pull on the cable spins the turbine and generates energy.
We could then angle the kite to drift back in,
reeling in the cable until we were ready for it to pull again.
It’d end up working kind of like a rowing machine at a gym.
Ditching the big metal stalk means that airborne wind energy systems
would require far less concrete and steel,
which are energy-intensive,
and could get to those higher, stronger winds.
The process of manufacturing, transporting, and installing airborne turbines
would be easier as well.
One company says that their prototype that has a capacity of 100kW –
enough to power a couple dozen homes –
and can set up by two people in 20 minutes.
It could be especially good in places
where traditional wind energy can’t go,
like steep terrain –
picture flying these off the edge of cliffs.
Or they could be used in remote locations
where it just doesn’t make sense to try to transport huge conventional turbines.
When folks have run the numbers,
it’s been predicted that it has the potential to produce
about the same magnitude of power as conventional wind,
while being cheaper and less impactful on the environment.
So okay, that all sounds good, right?
Airborne wind is probably not going to replace our whole grid,
but it could be a new tool in our arsenal,
one that could expand our ability to produce green electricity
and maybe even make it cheaper.
Now’s the part where we explain why we don’t have these already.
A lot of what we’d need, we more or less know how to make it.
We can make kites and balloons.
The trick is that in order for this to really work in the way we want it to,
you need these things to work
reliably, safely, and, in many cases, autonomously.
You’ve heard of self-driving cars?
These would be self-flying kites.
But that’s a challenge.
We’ll need computer systems that can understand and adapt
to changing wind directions,
and be able to know when to just ride out a random gust,
or hunker down from a storm.
Maybe the most challenging thing will be launching and landing,
when the kites or blimps go up or come down.
And if these aircraft are part of a whole wind farm, each individual aircraft
will need to be in sync with the ones next to it
so that each one doesn’t cause too much turbulence for its neighbors.
Add to that the need for
redundancy and risk-management,
and things get pretty tricky.
There’s also some stuff that we should probably research some more
before going ahead and installing everything,
even if the technology is technically ready to go.
One thing is that we need more research on potential impacts on birds and bats.
A study from Norway suggested the impact on birds is low,
and a theoretical model suggested
it would only cause about as many problems as conventional wind.
That danger isn’t negligible.
But it’s also not a leading cause of death for those animals.
And there are ways to make either kind of wind safer for flying animals,
like adding lights or paints to steer them away,
or being thoughtful about where to build new wind farms.
We still need more data, though.
Another thing is figuring out if people who live nearby
will be comfortable with this stuff in their backyards,
which…
I dunno, if they have cool designs on them.
I think it’d be neat to look at.
We also need to know how best to operate airborne wind safely
near other infrastructure,
and what kinds of landscapes they’d be most effective in
compared to conventional turbines.
Today, a number of prototypes or proof-of-concept projects
are being tested or developed.
Airborne wind energy systems haven’t yet gotten
to the point where they’re ready for the market,
but there are pilot projects and pre-orders.
So in the near future,
that image of looking out a window,
seeing a bunch of kites,
and knowing they’re to thank for your electricity?
That could totally be a thing.
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