- Welcome to "Engineering with Rosie",
today's video is going to be about wave energy,
and so I brought my camera with me into the surf.
Surfing is something that I really love to do,
love to take the energy provided by nature
and turn it into a really fun activity.
And of course you can also use
this same power to generate electricity.
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Any surfer or anybody who's ever been dumped by a wave
in the ocean, knows all too well that massive amount
of power that is present in the ocean.
So it seems like such a great opportunity to add
to our sources of renewable generation,
to be able to make more green electricity.
And I feel like we've been hearing
about wave energy projects for decades now,
but we still haven't really seen it gone mainstream
in the same way that wind and solar have,
over that same period.
And I wanted to investigate a bit more
about what are the engineering reasons for this?
What are the technology challenges
that have proved so difficult to solve,
that is the reason for why we haven't
yet begun to harvest a large amount of the power available
from waves for renewable energy generation?
And also I'm interested, are they on the brink,
are these problems about to be solved,
are we gonna see a massive increase
in wave energy any time soon?
Will this be a big part of our transition
to a renewable, green future?
Come with me while I find out,
and I will catch a few waves along the way,
well, I hope I will anyway.
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Okay, so the first thing we need to talk about
is probably what is wave energy.
So, every wave starts off as a ripple.
You can see the water surface today,
it's a little bit stirred up,
there's not a lot of wind, but just the light wind,
the turbulent air over the top of the water,
stirs up little ripples.
And then wind pushes on one of these raised ripples,
it can build into a bigger ripple,
and then over time, if the wind is pushing
in that same direction, it will build bigger and bigger,
until eventually it becomes a wave.
And the cool thing about ocean waves,
like any other kind of wave,
the water itself isn't traveling
in the direction of the wave,
it's just energy traveling through the water.
So it's like the same thing as my voice
is energy traveling through the air to the camera,
not actual air particles traveling
from my throat into the camera.
That's really great for surfing because it means
that you can have quite big waves on a day like today,
when there's not much wind around,
and that's really, really nice conditions to surf.
But it makes it a little bit challenging
for wave energy engineers, because there isn't a lot
of water moving in the direction of the wave,
which means you can't use that flow to directly turn a turbine
the same way that hydroelectricity is generated.
So they have to come up with an indirect way
to use this motion, to generate electricity.
There's a few ways that they can do that,
actually there's a tonne, like 10, 50, 100,
I don't know how many,
but there's so many different wave technologies out there.
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So the waves here today actually were formed
probably thousands of kilometers away,
and the motion of the water,
it's not in the direction of the wave,
each water particle actually travels in a rotational motion,
and wave energy engineers are usually looking
at three different components from that
to try and extract energy.
There's an up-down motion called a heaving,
and you can see this when the waves pass,
unless the surfer's actually catching a wave,
you're just gonna bob up and down with the wave
in the same position, just like this one passing now.
There's also a forward-back motion, called surging,
and then a rotational motion, called pitching.
So wave energy engineers are trying to use one or more
of these three types of motion to generate electricity.
So that's not as easy as in hydroelectricity,
where the water just directly falls on a turbine
and then pushes it around, which turns a generator.
So wave energy can't really directly turn a generator,
so wave energy engineers have to come up
with a different way to generate electricity.
They can use one of those three motions to drive a pump,
which will compress a fluid, like hydraulic fluid or air,
and then they use that compressed fluid to drive
a turbine around, and that's connected
to a generator which generates electricity.
That's one aspect of wave energy
that makes wave energy engineers jobs harder,
that they have to translate one
of these linear or rotational,
that they have to translate the heaving, or the surging,
or the pitching, into a way to generate electricity.
So usually they'll end up having to add
some extra components which adds complexity,
and cost, and can decrease reliability.
A lot of the wave energy companies that have come and gone
have had problems with reliability,
even for just like really simple components,
like a off-the-shelf cable that failed
or bearings that failed.
But with a small company, they don't have a lot of cash
behind them to recover from those sorts of things.
And then they also struggle because to repair these systems,
you need to get into the ocean to repair them.
Then of course, probably the most obvious challenge
that wave energy engineers face is trying to get
these complicated devices to last a long time in the ocean.
The ocean is such a hostile environment,
there's salt water, which can cause corrosion,
there's seaweed that clogs things up,
animals might build their homes in unfortunate places.
And of course, installation and maintenance mean you gotta
get people out to the site, and then probably get underwater
to repair components.
So that adds a lot of costs.
It's not all difficulties,
there's a lot of opportunities too,
and that's why there's still a lot of companies
that are sure that they're going to get
their technology to work, and become an economic way
to generate renewable energy in the future.
Most of the world is covered in ocean
and there's waves all through that,
it's a variable source,
but it's not nearly as variable as solar,
where it's dark every night, and often there's clouds.
It's also not as variable as wind.
So you can reduce variability in the system
if you add in wave energy into your mix.
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All right, so that pretty much exhausts everything
that I know about wave energy.
And I still don't feel like I've really figured out
the answer to why wave energy hasn't taken off yet.
Yeah, okay, so there's a linear motion
that needs to be translated to a rotational motion,
but that hasn't stopped piston engines from being
the main way to power a car for the last 100 years.
Wave energy devices are more complicated
than wind or hydro, or other ways
where you can directly turn a turbine,
but, you know, a jet engine is really complicated,
but it doesn't mean that people
have been flying around in hot air balloons,
which are a lot more simple.
So neither of these reasons really,
really gives us a good enough explanation
for why wave energy hasn't taken off yet,
and it definitely doesn't prove that it's never going to.
What I'm gonna do next is talk
to some experts in the industry,
and find out what are the technical challenges
that they have solved already in the past,
what are the big ones left to solve,
and whether they think that wave energy
is going to become mainstream in the near future.
So keep an eye out for future videos,
where I'll be looking into specific wave energy devices
with experts from the field.
People, look out for those videos in the future.
And in the meantime, please like and subscribe,
and if there's any topics you didn't understand
then make sure you leave a comment for me
and I will reply to those.
And I also love it when people leave suggestions
for new video ideas,
so please leave those in the comments too,
and I'll see you next time.
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