[dramatic music]
There's the O2 superstructure.
We've got a whole length
here of just over 72 meters
which is actually by the
same size as a 747 jumbo jet.
The reason that we need such a big hull is
that we're generating a lot of power.
So we need to actually have
buoyancy to counteract the load
that is coming from the rotors.
So each rotor is imparting
about the same thrust
as a jumbo jet engines taking off.
[suspenseful music]
A global industrial revolution is underway.
Yes, we have a technological challenge
for our environment, for the
wellbeing of the population
and planet, for civilization.
Driven by passionate dedicated individuals
intent on shaping a new world.
I do it because I look at
my kids and I honestly,
I'm convinced that this is the way.
A cleaner world.
There is a way forward
other than burning fossil fuels
out of our funnels.
A greener world.
This wind farm is producing
more hours of power
into the grid than all wind farms in the UK
and probably in the world.
What we've done in the past
is not going to solve these challenges.
We need to find new ways.
And I think the only way to do that
is to bravely step forward
and implement technology.
Together they are pushing engineering
to its limits
to create extraordinary machines
that can protect our planet for the future.
[soft music]
[upbeat music]
Anyone who has spent time by the coast
will have witnessed the
raw power of the ocean.
As tides rise and fall twice a day,
vast amounts of water
swirl around the earth.
This is a huge energy source
that's currently largely untapped.
Half a billion tons of seawater an hour
go through these gaps.
Those are titanic forces.
An estimated 3000 gigawatts are available
to be harvested globally.
Enough to power a
third of the earth's homes.
Yet compared to wind and solar,
the technology needed
to harness tidal power
is still in its infancy.
And the challenges of operating
in these environments are enormous.
The ocean can be
cruel at the best of times,
and then you'd move that water at 10 knots,
which is like 100 knot wind.
So you can imagine that's a very,
very, very aggressive environment
for these machines survive in.
Yet there are teams of engineers
around the world determined
to take on that challenge
to help the planet.
Their goal is to build
machines that are tough enough
to not only survive these
conditions, but thrive in them.
The wind has been harnessed,
solar's been harnessed,
we're trying to bring a
new industry to the world.
Although these turbines
are destined to be submerged below the sea,
the vast energy they're designed to harness
owes its existence to a
phenomenon high above our heads,
the movement of celestial
bodies through space.
[upbeat music]
[dramatic music]
The moon is closer to the earth surface
than it is to the center of the planet.
That means it's gravity
pulls slightly harder
on the ocean nearest to it
than on the rest of the earth,
creating a bulge of water.
The moon's gravity also acts
more strongly on the center
of the earth than on the furthest ocean
creating another bulge.
These two swells of
water appear as high tides
at the coast.
As the earth spins,
both of them move
around the planets surface
so that most places
experienced two high tides a day
and two low tides.
Twice a month when the
earth, moon and sun align,
their gravity is combined
and you get even bigger
tides called springs tides.
The rise and fall of the
earth seas and oceans
represents a vast amount of energy.
People have harnessed that
power since time immemorial.
And a handful of tide
mills still make flour today.
A tide mill has been here for 850 years.
Grain would be grown here,
collated at this mill and then processed
and then it could be easily shipped away.
Dan Tarrant-Willis knows the rhythm
of the tides as well as anyone.
The tide affects my life in a beautiful way
because I kind of live by the tide.
So I know I'm working if it's low tide,
if it's not low tide, I'm not.
[dramatic music]
Behind the building is a millpond.
When the tide comes in
and the water level rises,
the pond fills.
It has a one way valve in it
so as the water rises
it fills the millpond,
that fills up to the height of the tide.
We then wait until
low tide and at low tide,
we empty the water that we've captured
at high tide underneath our wheel.
The wheel is connected to a shaft,
which turns a set of millstones.
That turns at about 50 RPM,
which is perfect for
turning wheat into flour.
There are two low tides
in each 24 hour period.
I basically only got two
hours a day that I can mill.
During the industrial revolution,
tide power gave way to
coal driven steam power,
which was available on demand.
After that, tidal technology
almost disappeared
with a notable exception.
In 1966 a tidal barrage
was built across the mouth
of the La Rance River in
France that still operates today.
As the tide rises and falls water pours
through 24 turbines
generating enough electricity
to power the nearby city of Rennes.
But the structure was
very expensive to build
and it damaged the estuaries ecosystem,
Interest in tidal energy reached a low ebb.
[dramatic music]
Yet recently,
engineers are starting
to look to the ocean again.
The climate crisis has given fresh impetus
to finding clean energy sources
to replace coal and
gas fired power stations.
And tidal energy has a crucial advantage
over wind and solar power.
The greatest thing about
the ocean is its dependability.
We know that the tide comes in and out.
We have tidal charts going
back hundreds of years.
That's always going to be
that set amount of energy
that time of day in the tide.
And we can rely on that.
That's the biggest
upside of what we try to do
with marine energy.
[upbeat music]
Drew Blaxland of SIMEC Atlantis
has been working for
decades towards a new way
to capture the tides power.
Now it's being put to the test.
June 2016, the AR1500 tidal
turbine is being assembled
at a research center in Northern England.
This is a very exciting moment
for myself and everyone in the team.
This is the world's first
commercially viable tidal turbine
for the world's largest tidal
energy array in the world.
It's designed to generate power
in the open ocean.
[dramatic music]
The machine looks like a wind turbine
that sits on the seabed,
It's driven by tidal currents.
These are created by water flowing
towards parts of the sea
where the tide is rising.
When the tide changes, the
turbine rotates to catch the flow
in the other direction.
The current drives the
rotor around turning a shaft,
which goes inside a waterproof
casing called a nacelle.
There, a generator produces electricity,
which flows back to shore
through an undersea cable
where it connects to the grid.
Each unit is designed to
generate enough electricity
to power 650 homes day in, day out.
It's much simpler and cheaper
to build than a tidal barrage
and should have less
impact on the environment.
The greatest thing about what we do is
the turbines turn up
off the back of a ship,
lots of activity.
It's beautiful, pristine environment.
And after we leave,
it's still a beautiful,
pristine environment.
You don't know where there
and there's now power being generated.
But before disappearing beneath the waves,
the turbine must first prove itself on land
without its blades.
The team connect the shaft to a test rig
to simulate the extreme dynamic loads
it will experience under the sea.
Over the course of six weeks,
the powerful test rig drives
the shaft with the same force
as it will experience
under the full tidal flow.
But as well as turning the shaft around
the test rig can apply
hundreds of tons of force
pushing it back and bending it to the side
just like the turbulent ocean.
Despite the punishing loads,
the powertrain bearings and control systems
all work perfectly.
It's an absolutely huge milestone for us
and the feeling is absolutely excellent.
It's the kind of thing that
you spend your whole career
building up for is these moments
when you can say that all that hard work
was really worth it.
The turbines ultimate destination
lies off the Northern coast of Scotland,
where the tides are legendary.
[upbeat music]
Orkney, a remote wind swept archipelago.
The raw power of the ocean
around the islands is breathtaking.
For 15 years, Neil Kermode
has run a Marine test site
for wave and tidal energy devices here.
There's a huge amount
of tidal energy in the waters
just around Orkney.
It's estimated it's something like 20%
of Europe's tidal energy
are here in the waters
around these islands
Traveling around the islands
can take much longer at
certain times of day than others,
depending on which
direction you're heading.
Well, it appears that we're pairing along
at a brisk eight knots or
about 10 miles an hour.
But actually, if you look at the side,
you can see we're not moving at all
because the boat is having
to work against the tide.
Although the vessel is moving rapidly
through the water,
the water itself is flowing
at roughly the same speed
in the opposite direction.
Despite its appearance,
the water is moving faster
than most whitewater rapids.
The reason the flow here is so fast is
because of Orkney's unique position.
Orkney has got two
bodies of water around it.
It's got the North Atlantic
and it's got the North Sea,
and the North Sea at the moment is higher
than the North Atlantic.
So the water is running downhill
towards the North Atlantic.
And six hours later, it all turns
round and goes back again.
[dramatic music]
As the water pours
from one sea to the other,
it's forced into narrow
channels between the islands,
making it speed up even more.
When the tide changes, the
current slow down and stop,
before starting to flow back.
Half a billion tons of seawater an hour
go through these gaps.
Those are titanic forces.
These powerful currents
are known as tidal streams
and they're a huge potential
source of clean power.
We're standing effectively
on a river of energy,
that's roaring past us.
It's driven by the position
of the moon and the sun
and that's never ending.
So if we can tap into the currents
and the energy that's in this water,
that gives us a, frankly, an
inexhaustible power supply.
Experts estimate tidal streams in places
like Orkney could one day meet a fifth
of the world's electricity demands.
The stretch of water with
the most potential here
is the channel between the
islands and mainland Scotland.
The Pentland Firth.
Here, the water flows so fast
it's been called the Saudi
Arabia of tidal stream energy.
There's enough power to generate
a vast 4.2 gigawatts of electricity,
more than the world's biggest wind farm
and solar farm combined.
The flow in the Pentland Firth is fantastic
for tidal turbines.
You have the North
Sea and the North Atlantic
and the tidal exchange between the two,
you get tides up to 10, 11 miles per hour
which is great for tidal generation.
It's 100, 120 feet deep, 30, 40 meters.
You really couldn't ask
for a better place to do tidal
and reasonably close to shore as well.
SIMEC Atlantis will
deploy four turbines here
at first with plans to
scale it up to an array
of hundreds of machines in the future.
The first AR1500 turbine has arrived.
And it's three 30 foot
long blades are assembled
into the rotor, spanning an
area the size of a tennis court.
The bigger your rotor is,
the more power you're able to generate,
the more yield you can
take for any given megawatt.
With the blades on,
the machine stands 78 feet tall.
It's four to five stories high,
it's 150 ton plus the foundation,
it's 1300 ton of steel.
It's a big beast.
The huge structure must be transferred
to a ship to sail out
into the Pentland Firth,
one of the world's most
challenging locations.
The tide is roaring
along for most of the day,
a good 20 out of 24 hours.
Up to 10 miles an hour,
depending on the site.
And you've got to get in there
in the four one hour maximum
hour periods to do your work.
So you've got to find ways
of designing your equipment
and everything you do for
that little tiny period of time.
It's almost military precision.
You need to go into it almost
like you're planning a battle
and you go out, jump out of your trench,
do your thing and then
scurry back in your trench
for the next four hours
and have another crack.
A high precision operation like this
needs a sophisticated
dynamic positioning vessel.
It uses satellite technology
to remain stationary
despite the currents,
but the water here flows so fast
that the operation must still be completed
in the short window of slack tide,
when the current slows down
before it changes direction.
So what we've actually done
is we've installed cameras
in the bottom of our turbine.
You've also got an ROV,
a remote operated vehicle,
which is a robot effectively
that can watch the
turbine as it comes down.
Imagine that as the top of a foundation,
big pole, 2.5 meters diameter
sticking out of the seabed
and you're aiming for that and
that's the female connection.
The bottom of the turbine,
this is now coming down
from the top, is the male connection.
The tide has now turned
and the water's starting to flow.
It's already pushing
the turbine out of line.
In a few minutes, the
current will be too fast
for the vessel.
But if they abort, it
means a six hour delay.
Time is money, every day we're off shore
with large vessel assets
costing 50,000 a day plus.
So time is absolute critical offshore.
The team have one last chance
to make the connection.
The next trick is
you don't even have to get it that close.
You have to get it within tolerance.
And we have special
features on our stabbing system
that allow it to turn on its
own as it comes together.
And that's basically like a bayonet fitting
that brings it together.
Once it's together, that's it.
There is no extra fasting.
There's no clamps.
It's 150 tons, about 90 ton underwater
because you lose weight
as you go underwater
and it sits there just on gravity.
Three more turbines are also taken out
and installed in the Pentland Firth,
a project called MeyGen
that can power 2600 homes
with green electricity.
So at the MeyGen site we
have four 1.5 megawatt turbines.
That's reasonably small
in comparison to wind,
but it's the start of tidal arrays.
As well as installing the turbines quickly,
the same system can also
be used to retrieve them
for maintenance.
But they still need
expensive equipment to do it.
So if the turbines need many repairs,
the mounting costs could be prohibitive.
On the West Coast of Scotland,
a different tidal device is being developed
to avoid that risk.
Connel on the shores of Loch Etive.
[uplifting music]
During spring tides
conditions here draw kayakers
from around the world to
brave the famous tidal race
called the Falls of Lora.
Evidence of the plentiful
tidal energy available.
The water flows up into Loch Etive
and then it comes out in a great rush
past the Falls of Lora.
And it's almost like a horizontal waterfall
where it really rushes through there
at a huge rate of knots.
Jason Hayman
is CEO of Sustainable Marine Energy.
Another tidal stream
startup based in Scotland.
His vision has been influenced
by seabed mounted turbines
he's worked with before
We were installing a
first-generation device
on the seabed.
And so we looked at that
and we said, "That's great,
we can see the potential for this
but it has to be far simpler
and far more cost-effective."
And that's when I decided
to look at other ideas.
And that's why we
started Sustainable Marine.
[dramatic music]
In 2017 Jason's team assembled a new device
to harness the power of
tidal flows at the Falls of Lora.
But he decided to try a different approach.
His plan was to build
and test a floating platform
with tidal turbines that
can be lowered beneath it.
We thought by having a floating platform,
then we can make it more
like a conventional ship
and we can take a little boat
and we can go there whenever we want.
And if we need to change a fuse,
if we need to try a new blade,
if we need to try
anything new, we can do it
and it's it's easy
The platform is held in
place by mooring lines
while four relatively small rotors
are lowered down into the water.
As the tidal stream flows past,
the turbines generate
When the tide turns,
the platform is carried
around by the current
so it can produce electricity
on the rising and falling tides.
We have producing electric current
with the turbine submerged under the water
and this is then
transferred to the container
for power conversion and
then be fed into the grid.
This is the next generation of tidal power.
Unlike sea bed mounted turbines,
floating platforms are not hidden from view
beneath the waves.
So they do have an impact on the landscape,
but being at the surface
does have other benefits.
The water flows faster at the surface
because at the bottom of the ocean,
you have the seabed
and the water moving along
next to the seabed encounters friction.
It has to get past all the crevices
and rocks and everything.
Therefore you want the
turbines positioned as high
in the water column as you can get them
to get the maximum amount of
energy out of the water column.
With a faster flow of water,
even small rotors can
generate powerful forces.
So the team needs to check
whether the mooring lines can hold firm.
The thrust force that's
generated by one of our turbines
is the same as a Eurofighter Typhoon
when it's on full afterburner.
[jet roaring]
So if you imagine with our platform,
that's like saying, let's
take a brace of Eurofighters
and try and put them on a leash
and then hit the afterburners.
So that's how big the challenge is.
The trial in Scotland has proved
that the mooring lines and platform
can withstand the colossal forces
and generate electricity reliably.
But to be used more widely,
the team also need to
check how their technology
affects wildlife.
It's all very well going
and deploying something
into the natural environment and saying,
"Hey, this is gonna help us
avoid greenhouse gas emissions,"
but what impact is it gonna have
on the local environment?
And we need to understand that to ensure
that we don't create a situation
where we create unintended consequences.
Researchers are monitoring the behavior
of marine animals around the platform
and investigating what
effect the turbines could have.
Tidal turbines are mechanical structures.
They make noise.
There's often concerns about
the amount of noise they make,
that is too much, that it
pollutes the environment.
However, we've got other
concerns about tidal turbines
that they might be a
risk for marine mammals
and other large animals swimming
around in the water column
and the risk is that they
might bump into the turbines.
So it's important that the noise
that the turbines are making is loud enough
for the animals to hear it,
at a distance it's far enough
away for them to move away,
but not so far that they
avoid the whole area
where the turbines are
and the environment they're going through.
So there's a kind of sweet spot
between being too loud
and causing disturbance
and being too quiet and
then having a collision risk.
So we've had seals and
porpoises and even whales
come past the platform
and we've had no signs of any interaction
and they just seem to cruise on by.
The seals actually seem to
like to play behind the platform
somewhat in the wake.
And now what we're
really trying to understand
is how fish interact around the platform
and how they avoid the turbines.
After successful test campaigns,
the team intended to scale up the device.
As head of research and development,
Penny Jeffcoate worked
with the engineering team
to create the new blueprint.
One of the things that we learned
from having a four turbine platform
was that the platform
and the mooring system
go perfectly fine with all
the thrusts and other loads
that we were putting through the system.
So it meant that we felt confident
that we could design something
that could accommodate
more turbines and more power
and more thrust and more load.
Before building the new larger platform
at full scale, they had
to be sure the design
could withstand the extreme
conditions it would face.
[upbeat music]
The FloWave testing
tank in Edinburgh, Scotland
is the only place in the world
that can reproduce any sea state.
With a circular shape,
it can create every possible combination
of waves, currents and depth.
This means that we can
completely accurately replicate
what we would have in the real size,
but at tank conditions.
So it means that we can have
flow coming in one direction,
waves coming in another direction
and test this at different depths
to see how these different
phenomena interact.
In 2018 Penny's team built a scale model
of the new design.
The six rotor platform is destined
for the Bay of Fundy in Canada,
a location with notorious conditions.
It has the highest
tidal range in the world.
So you've got a 16 meter tidal range.
So the flow speeds that
we experience at the site
are between five and six meters per second.
So for the mariners out there,
that's more like 10 to 12 knots.
So incredibly fast moving water.
As well as dealing with the rapid flow
and constantly changing water depth,
the platform must be
ready for the worst weather
that nature could throw at it.
We try and capture as many
different combined conditions
between flow and waves that we can do,
and this might be quite benign.
And then we also try to
do right up to the extremes.
So imagining a big storm coming through,
a big hurricane coming through,
massive waves coming through the site.
How does the platform
cope when it's confronted
with these monster waves coming through?
As the tank test began,
the paddles created miniature
versions of storm waves.
Under water pumps began driving the flow
rapidly across the tank.
There is a certain feeling
when you're in a tank
and you hear all of the pumps ramping up
and it's brilliant
because it just builds up
that sense of excitement
and anticipation in you.
When we're trying to
replicate the Bay of Fundy
where we have these really extreme tides,
it's actually pushing the
tank right up to the extremes
of what it can cope with as well.
But as the pumps reached full speed
something was not right.
Sometimes things don't
go quite as you're expecting.
And this happened quite unexpectedly
that we had a mooring suddenly break on us
as we were operating at the fastest flow.
The team rushed to
find out what went wrong.
And the answer was soon clear.
It was not through engineering or design.
It was completely through
me putting the models
together slightly wrong.
So I apologize for that to the team.
But it was a really
interesting thing to learn from
because we saw exactly, well,
what happened to the platform?
Where did it go?
How did it move in the tank?
And naturally, even though
we lost one mooring line,
the platform worked
perfectly fine, it coped.
Once the mooring line was fixed,
the waves and currents were ramped up again
And this time everything went to plan.
We were throwing the
fastest flow, the highest waves
and it was just performing
exactly as we expected.
So it was a real sense of
such relief and excitement
and just real proud of our engineering team
for having designed
such a brilliant product
that did exactly what
we were expecting it to do
and did exactly how the
numerical models predicted.
And we had great confidence
that, yes, we can build this.
We can put it in the sea
and it's gonna do exactly
what we need it to do.
On the East Coast of Canada,
the Bay of Fundy in
Nova Scotia is the ultimate
tidal testing ground.
The full-size platform is
being assembled on the banks.
On the 1st of February, 2021,
it's finally ready to be launched.
All they need now is
for the tide to come in
and raise the water level high enough.
Behind me you can see
PLAT-I 6.40, our tidal platform.
And in a few hours it's gonna
be traveling down this slip,
it'll achieve high tide at
about one o'clock today.
We have beautiful wind
conditions today, very low wind.
So very, very exciting day.
This is a culmination of many years
of research and developments.
And can't wait to see
our platform in the water.
At high tide, the platform is maneuvered
down the slipway and into the bay.
[upbeat music]
It will be more than a
passage with one of the fastest
flowing tidal streams in the world.
At full flood, four times more water
moves through the Bay of Fundy
than all the world's rivers combined.
Because it's so much energy,
it's a very, very challenging site.
It's the Mount Everest of tidal sites,
and there have been some attempts
to deploy technology there before,
but unfortunately nothing's
actually managed to work
for a prolonged period of time.
If it survives the ultimate test,
this still relatively small platform
could one day provide electricity
to remote islands and coastal communities.
[uplifting music]
But another company back in
Scotland think bigger is better.
At a construction yard in Dundee,
the world's biggest tidal
turbine is taking shape.
The Orbital O2.
Making larger turbines
means you need fewer of them
to generate the same amount of power.
That means fewer cables,
anchors and mooring lines.
And less infrastructure
means cheaper electricity.
But CEO Andrew Scott
knows that building bigger
also has its challenges.
So there's the O2 superstructure.
We've got a whole length
here of just over 72 meters
which is actually about the
same size as a 747 jumbo jet.
The reason that we need such a big hull
is that we're generating a lot of power.
So we need to actually have
buoyancy to counteract the load
that is coming from the rotors.
So each rotor is imparting
about the same thrust
as a jumbo jet engines taking off.
Each of two rotors on the O2
will be 65 feet across.
Together, they trace out a total area
bigger than a basketball court.
As the rotors turn, as well
as generating electricity,
they'll create a powerful torque
pushing the front of the
machine under water.
The buoyancy of a long tube full of air
counteracts the turning force,
keeping the nose above water,
but in doing so it causes the structure
to flex in the middle.
The rotors exert
tremendous forces on the hull
and the hull has to react all this force.
And during this process,
the hull bends like a banana
Engineer William Annal has responsibility
for the turbines superstructure.
He knows they need to
reduce the bending motion
as much as possible.
So you can see here that
we have to use very large pins,
really thick bits of steel
in order to resist the forces
that are being exerted on the structure.
Now, the reason that we do this
is to bring the stress levels right down.
Some of the better plate that we have here
around the about 70 millimeters thick.
Even the hull has shell thickness
of up to 40 millimeters thick in places.
Now, if you compare
this to a commercial vessel
or a military vessel
like an aircraft carrier,
you'll find shell thickness
around eight millimeters.
[dramatic music]
When the hull was being fabricated,
shaping and welding
such thick pieces of metal
into precise tubes was extremely demanding.
The hull structure has to be manufactured
with a lot of precision.
In order to resist the forces of the tide,
it has to have good uniform shape.
The tolerances that we're working to
are around about two
millimeters, over 3.8 meters.
So that's really high precision stuff.
This takes a lot of experience
because there's so many factors involved.
It's a bit of a dark art.
The design of the O2 is much
to Orbital's previous turbine, the SR 2000.
The SR 2000 was a tremendous machine.
It was a two megawatt tidal turbine,
two rows extracting energy from the tide,
weighed about 505 tons
and is absolutely enormous.
Like the O2, it has a long superstructure
with two legs to hold the
nacelles and rotors under water.
In 2016, the SR 2000 was unveiled
at the Harland and Wolff shipyard
in Belfast, Northern Ireland.
Before launch, the team
ceremonially blessed the vessel
with mugs of local scotch.
[uplifting music]
It was a lot more effort
making their SR 2000
than what we anticipated.
A lot of 12, 15 hour days.
So it took a lot out of us.
And for me personally, when
the machine was launched
there was a sense of relief.
And then there was a
quiet sense of satisfaction
for everything that we'd achieved.
When it was launched,
it was the largest tidal
turbine in the world.
The floating SR 2000
was towed north to Orkney
where it was moored in one of the world's
fastest flowing tidal streams.
Over the course of a two year long trial,
the turbine survived
waves over four meters high
and broke the record
for the most tidal energy
generated by a single turbine,
three gigawatt hours
in its first year alone.
This provided the 20,000
inhabitants of the islands
with up to a quarter of their electricity.
We made a lot of world records.
We made a lot of world firsts as well.
We had a very successful testing period
generating significant amounts of energy
from a tidal turbine.
And that hadn't been done before.
But although the SR 2000 performed well,
the team soon became
aware of a major drawback.
[suspenseful music]
The two legs holding the
rotors were designed to tuck up
underneath the body, making
it easier to tow to harbor,
but that meant the rotors and nacelles
would always be below the surface
and therefore hard to reach.
It was flawed, by having the nacelles
always under the water for the SR 2000
meant that inevitably either
through needing to access
for servicing or repair,
we were gonna be faced with a question
of having to get access,
and that would have to
be done either by lifting
the entire turbine out of the water
or put it into a dry dock.
Both of those scenarios
require a lot of downtime
and a lot of costs.
The team couldn't afford
to take that risk again.
Even something like a blown fuse
could take the turbine
out of action for weeks.
Andrew was determined to find a way
to make all the vital components
on their next turbine more accessible.
We knew that we had a challenge
around low cost maintenance and servicing
of the entire turbine,
including the nacelles.
So that was something
that we put as a priority
for the redesign of the O2.
One approach would be to change
the position of the legs so the blades
and the nacelles could
be lifted all the way
to the surface rather than being tucked up
underneath the hull.
But that would mean the
turbine could no longer
be put in a compact configuration
that could easily be towed and docked.
Then Andrew realized that if the nacelles
and rotors were accessible in situ,
that wouldn't matter
as it would never need to
be taken to harbor for repairs.
It gave us a bit of an hallelujah moment
in terms of how we operate these turbines.
And what that really
allows us to do is make sure
that the turbine spends most
of its life generating power,
which is what it's meant to do.
In July, 2020,
the mechanism for the O2 legs was tested
for the first time.
Lifting them right up to the surface
requires new, more powerful hydraulics.
The untested technology
must now prove that it works.
Today, we're just tasting the
hydraulic retraction system.
It's a huge amount of weight, 100 plus tons
it has to lift up to the surface.
So it takes a huge
amount of power to do that.
power, just to lift the legs.
The upper parts of the legs
have been attached to the body
ready to test the mechanism.
All that's left is to lower them down
to their working position
and then try to lift them back up.
We don't like excitement,
we test them to be well-planned.
I like a boring test.
[suspenseful music]
Okay. I'm gonna take the legs down.
The legs are fully
deployed with no surprises.
Next comes the 100 ton lift.
On the water, this will
raise all the vital components
up to the surface where
they can be easily accessed.
Success.
By January 2021, then nacelles are ready
to be attached to the legs.
Inside are many of the
vital mechanical components
including the gearbox,
generator and pitch control units.
The final components are the rotors.
Although tidal blades operate
along the same principles
as those on wind turbines,
working underwater makes a huge difference.
As a comparison this
wind turbine has a power
of about 11 kilowatts
and blade length of about six meters.
So to do the same with the tidal flow,
we'd only need blades of
about half a meter inland.
The difference is due
to the density of water.
Sea water is more than
The energy density in the tidal stream
allows us to generate a lot more power
for a given swept area.
Finlay Wallace is the lead
blade designer at Orbital.
The blade he's creating
for the O2 will be roughly
twice the length of
this small wind turbines,
but should capture 100 times more power.
[upbeat music]
The rotors are being
made in Gosport, England.
The team are using layers of carbon fiber,
a material that once treated,
will have the right strength and stiffness
to reinforce the structural
core of the blades.
The forces involved on the tidal blade
are orders of magnitude higher
than an equivalent wind turbine blade.
So standing up to the marine environment
is a real difference for me.
To form the core of the blades,
the carbon fiber must
be infused with the resin
and then heated.
We're actually standing
inside an oven at the moment,
looking at the main structure
of the O2 2000 blades.
There'll be four of these
produced, two for each rotor set
and they'll do the majority of the work
of transmitting the blade loads
from the tidal flow into
the turbine structure.
While the core of the
blade should be strong,
the exterior must be perfectly shaped
to interact with water and generate power.
I spent a lot of time fine
tuning the external shape
of the blade to present the smoothest path
for the water to flow over.
The water flowing past the blades
is what allows us to generate electricity
from the water itself.
[upbeat music]
The computer controlled cutter can exactly
recreate the hydrodynamic
curves of Finlay's digital design.
But the automated process leaves
unwanted ridges on the surface.
These are smoothed out by hand
to produce a perfectly polished edge.
Being able to kind of
stand in front of the molds
and see that it's kind of gone to plan.
As far as that's concerned,
it's been very rewarding.
In February 2021, the
blades arrive in Dundee
ready to be painted and attached.
Once in place, Orbital
will test the giant turbine
back in Orkney.
When they connect to the grid,
it should generate more power
than any other tidal stream turbine.
After that, they have big plans.
The long term goal is to
produce lots of machines
so that we can have farms of tidal turbines
in various sites around the
UK and around the world.
[uplifting music]
[upbeat music]
In the future, arrays
of tidal stream turbines
could generate huge amounts
of power for local communities
and national grids.
Yet despite the clear
promise of the technology,
some experts question
whether tidal stream power
could ever become as
widespread as wind or solar.
Surveys suggest the number of places
with fast enough currents is limited.
In the vast majority of coastal locations,
the water simply doesn't flow fast enough
for seabed mounted or floating turbines.
[upbeat music]
However, a company on
the West Coast of Sweden
is trying an approach that
could work in more places
with a design that's
fundamentally different
from other tidal stream turbines.
Rather than being fixed in place,
this turbine is designed to move/
CEO Martin Edlund
believes this is the secret
to extracting more power
from slower currents.
The Minesto technology is unique
compared to hundreds
of other tidal solution
that exists today.
So what we do is that
we basically fly an airplane
under water tethered to the sea bed.
This technology can be used
in all continents and all
oceans around the globe
and that's a huge advantage.
The Deep Green 100 prototype
has wings like a plane
but it moves more like an underwater kite.
[dramatic music]
On a day with slow winds,
there's a trick that
allows you to still fly a kite.
The wind speeds today
is really near to nothing,
about one, two meters per second,
but flying the kite in a figure eight,
allow us to get more energy out of it.
When there's not much wind
a stationary kite can't stay aloft
as there's not enough
power in the air to lift it.
The only way to fly a
kite in these conditions
is to keep it constantly moving
faster than the wind itself.
That way it collects and combines the power
of the wind over a much larger area
keeping it in the air
Our turbine is like a normal kite,
but instead of power by
wind, it's powered by water.
That's exactly how a kite behaves on water
in this figure eight behavior.
Minesto's subsea kite
is designed to be tethered
to the sea floor and to move continuously
through the water in a figure of eight
flying much faster than
the water is flowing itself.
The rotor on the front is pushed round
generating electricity,
which flows down the
tether and back to shore.
By harvesting the
power of the flowing water
over a large area, it can
extract many times more power
than if it were fixed in
place like other turbines.
At the workshop, the gearbox, generator
and the rudder module are being tested.
The team are checking that the systems
are correctly calibrated
so it can maneuver reliably under water.
We're doing some fine tuning
of the most important section
of the kite that's actually doing the work,
just a rudder module,
rudder elevator module.
So we have the rudder here that controls
the steering of the kite
And then we have the elevators
which is basically the throttle,
The rudder module is entirely responsible
for the kite's trajectory under water.
If it doesn't move as intended,
the kite could crash into the sea floor
or tie itself up in knots.
Maybe one degree of
difference has a huge impact
on the performance of the system
so we really need to nail this
so we get the most out of the system.
The rudder and elevators are connected
to an onboard control module.
Once the team has chosen
how they want the kite to behave,
it flies automatically.
This is what we call
the kite control module.
That's where the magic happens.
We create system code clearly,
and then we program
it into this control unit.
And then we just tell the kite to run.
And it will then automatically
adjust its actuators
within given parameter that we've set.
It could be kite speed,
depth, and so forth.
And within those boundaries,
the kite's making its own decisions
and is really good at it.
To make the right decisions,
the kite has a gyro unit and sensors.
These tell the control module what depth,
speed and orientation it has at all times
so that it can respond appropriately.
The team need to check all the sensors
are working as intended.
If you imagine you have your smartphone,
where you can flip the screen
and you can roll ba*ls in
games and those kind of,
it's more or less the same thing.
We set the kite into motion and we can see
that rudder module reacts
the way we want it to.
So we're happy.
Minesto have been testing underwater kites
for 10 years around the coasts
of Northern Ireland and Wales.
During that time they've
developed their seabed
tethering technology and
devised the most efficient systems
for transporting the power back to shore.
All this while improving the technology
that flies their kites through the water,
leading to the development of
the high performance DG100.
We needed the robust systems to fine tune
and work with control system,
get all the functionality in place.
But what we're doing now
is that we are aiming higher
and we're moving towards
real performance outputs
of what we're doing.
I think it's fair to say that
this version we have now
is more a formula one
car than a robust safe Volvo
that we've been working with before.
Minesto chose the Faroe Islands
in the North Atlantic to trial the DG100.
Here the tidal currents are much slower
than in Orkney or Canada.
But Minesto calculated they
could still supply 100 kilowatts
of electricity to the grid,
enough to continuously
power over a thousand TVs.
The flows in most locations
are not high enough
for what we may label
conventional tidal turbines.
For us, this campaign is the
key campaign to really prove
the high performing energy
conversion that we're claiming
which makes it then
sort of the absolute most
important testing campaign
that we've had in Minesto.
First, the team had to
build the infrastructure
to affix the kite to the sea floor
and bring the power on shore.
Once that was in place,
the kite was towed out to sea.
But during tow testing, the team realized
that there was a problem
with the electrical connection.
The system had detected
a leak which had to be fixed.
You can imagine, I
mean, we were all excited
about this controlled system team in place.
Everyone really wants
to see this thing flying.
And then there is some
minor insignificant part
of a component that
sets us back again in this.
That's sort of the nature
of pushing the boundaries
of technology and driving innovation
After three weeks and a lot of late nights,
the kite was back in the water.
Towards the end of November,
we had really good tidal conditions,
good weather conditions and we said
that it's about time now
to get everything right
and hook this machine
up to the grid and fly it.
And we knew that we were
very, very close to success.
The tether was attached to the sea floor
and in the control room,
everything was finally ready.
The team were raring to go.
The kite sank deep into the
murky depths and out of sight.
Finally, the test could begin.
[suspenseful music]
We started running it in
continuous operations mode
with some safety belts on,
not letting it lose completely.
The target was 100 kilowatts of power.
We knew that the tidal
conditions were really good
so it was tempting also to
have a go at really optimizing
and driving the electricity production
to the peak levels of the system.
So we actually run the system
beyond the 100 kilowatts it's rated for.
[team cheering]
To everyone's excitement,
the kite reached 101 kilowatts.
Then continued rising up to 117.
[team cheering and laughing]
The atmosphere in the control room
went from a really tense
and concentrated environment
into really relief and joy
and people being really, really happy
and proud about what we've achieved.
Minesto's prototype
only generates a fraction
of what larger turbines can produce,
but they plan to build a
machine 10 times more powerful
which would thrust
them into the big league.
Around the world there are thousands
of potential installation sites.
All continents, and all
oceans have an abundance
of kinetic energy of
the kind that we can use.
And we talk about a capacity long-term
that will be in the range
of what nuclear is providing
to earth today.
So it's not just sort of a
niche technology in that sense.
It's something that will play a global role
in contributing to getting us
where we need to be as humans.
If Minesto successfully
scale up their kites,
this technology could hold
huge potential for the future.
[gentle music]
In the meantime, others are rapidly proving
that tidal stream energy
could make a big splash
even sooner with full-scale
turbines ready to go.
Atlantis have started
deploying their turbines
around the world.
We are busily planning
our first project in France.
We've just sent a turbine to Japan.
It's the first of its kind in Japan.
And we also designed and help install
the first 500 kilowatt turbine
in China earlier this year.
You've got so much
potential around the world
for the deployment of this,
we're never gonna be short of customers
Sustainable Marine are busy conquering
the Bay of Fundy in Canada.
If their platform works
there, it'll work anywhere.
I think where our technology
can really make a difference
is in these remote islands
and coastal communities
where perhaps they don't
have the best solar resource,
perhaps they don't have
the best wind resource
but we can give them a renewable
and predictable source of power.
And Orbital are putting finishing touches
to the biggest and most
powerful tidal stream turbine
the world has ever seen.
The challenge of climate change
doesn't need just one solution.
It needs lots and lots
of different solutions.
So we really want to
exploit this pioneering,
enabling a bit of technology
that we've developed here
to see it used as widely as possible
around the world to generate
clean sustainable power.
A new golden age of ocean power
could be around the corner.
energy was really pushed out
by fossil fuels because they were cheaper,
but we've now seen the problems
we're having with fossil fuels
and the impact it's having on the planet.
So I really see that tidal
energy is on his way back.
And frankly, I think tidal energy
is going to get his revenge
for being pushed out.
When it comes to energy,
could the tide finally be turning?
[uplifting music]
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01x04 - Tidal
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An engineering revolution is underway. Driven by dedicated individuals who are building extraordinary machines that will change our lives.
An engineering revolution is underway. Driven by dedicated individuals who are building extraordinary machines that will change our lives.