All language subtitles for How.Cities.Work.Series.1.1of5.Power.Games.1080p.HDTV.x264.AAC.MVGroup.org

(exciting music)

This time, we reveal how cities

are kept supplied with electricity.

Power goes out here, there's no show. (chuckles)

From the world's most advanced

solar power station...

For me this is the chance of a lifetime

to really make a difference.

It is the first of its kind.

We fly with the unsung heroes

who risk everything to keep power flowing.

I am an experienced helicopter pilot

and I think, why am I doing this?

This is unbelievable.

And uncover how tunnels

deep beneath Britain's capital

will keep the city alive.

What we're doing here is rewiring the whole of London.

(dramatic music)

Half the world's population

live in urban areas,

and the number is rising every second.

Each day is a race against time

to house, feed, water, and move

more than 3.5 billion people.

It's an impossible daily challenge.

The slightest glitch can bring a city to its knees,

and every 24 hours, it has to be done all over again.

This is the story of how cities work.

(light tense music)

Las Vegas.

This neon oasis in the heart of the Nevada desert

needs over 5,000 megawatts of electricity every day

to power the hotels, casinos, and light shows

that have made it famous.

The most impressive show in town

can be found on Freemont Street.

(exciting rock music)

Towering 30 meters above a pedestrian mall

is one of the largest LED screens in the world.

It spans four city blocks in Downtown Vegas,

and is one of the most spectacular shows in the city.

People are always attracted to bright lights.

Whether it's here, Times Square, the Strip,

people love going where the lights are.

A staggering 12.5 million individual

LED lights are carefully synchronized

to create a unique visual extravaganza.

(energetic rock music)

Every night, Freemont Street consumes enough energy

to power nearly 300 homes.

It doesn't come cheap.

The annual electricity bill

is close to half a million dollars.

Well, the Freemont Street experience

uses a lot of power.

Just from all the lights and LEDs,

and from the canopy itself, from the casino lights,

to the stages, and even here in the control room.

I mean, if the power goes out here,

there's no show. (laughs)

Electricity powers the life support systems

that keep our cities running.

Lights,

trains,

communications,

even hospitals rely on this invisible force.

Without it, our cities stop working and lives are at risk.

(exciting music)

In New York, the system is near breaking point.

Every day, the city consumes more electricity

than the entire country of Greece,

and every kilowatt is piped here

along a network of high voltage power lines.

But some stretches are over 40 years old

and in need of urgent repair.

If they fail, the whole system can collapse.

7:30 a.m.

It's Vinny Cartier's job to keep the power flowing.

Vinny isn't an engineer.

He's a helicopter pilot.

A lot of people think we're crazy,

but I love the guys that I fly with,

and I love the mission, and I love the challenge.

(light music)

Vinny is part of an elite team

who risk their lives to maintain

the high voltage power lines from the air.

The network runs over miles of countryside,

much of it inaccessible to a road crew,

so while Vinny does the flying,

Ryan Hill is tasked with carrying out vital repairs.

We have 1200 miles of conductor

and over 5,000 structures in our system,

so it'd be tough to get that by foot,

so if you do it by air, you'll get it done pretty quick.

Many cities around the world

are forced to turn off high voltage lines

to carry out vital repairs,

but New York's need to keep affordable power flowing

all the time is so great that Vinny and Ryan

have to work with half a million volts

surging through the cables.

One wrong move could spell disaster for them both.

You would think you would shut the power off

to maintain the lines, but it's very critical

to keep that energy flowing to the customer.

Each power line consists of multiple wires

that must be kept apart.

If two lines touch, the whole system could trip

and cause a blackout in the city.

Simple metal spacer bars separate the lines,

but some are old and could fail at any time.

Ryan and Vinny must replace them before it's too late.

These have probably been up there since the '70s.

If we let the spacers deteriorate and not maintain them

they'll eventually break off,

and then you'll have all the lines smacking each other,

and you wanna avoid that.

This is what's up there now.

Existing spacer.

And you'll have the two conductors running through here,

and as you see, this one's pretty old,

but they need to be replaced now,

so we're gonna go up there with the helicopter,

we're gonna install the new ones here,

so we're gonna take these four bolts off the old one,

we're gonna add these on it, put the new one on,

these'll be up there for a good 50 years now.

To get the job done,

the team needs perfect weather conditions.

We need calm winds, no gusts,

or else the machine will not be happy.

All right, so the weather's looking good right now,

but after about 10 o'clock it's gonna pick up a little bit

so we really need to get this done now,

so let's go do it.

With the wind forecast to pick up

in two hours time, the clock is ticking.

But before Vinny and Ryan can get to work,

they need to modify the helicopter.

This platform allows Ryan to get within touching distance

of the power line,

but hanging out so far on one side

will destabilize the helicopter,

so the crew add counter weights

to keep it precisely balanced.

You feel comfortable sitting on it?

Absolutely.

As long as you're flying it.

With their lives on the line,

there's no room for error.

Vinny has last minute checks to do.

Looking at everything three times.

Looking at every harness, every latch,

every bolt, every weld.

All the components on the helicopter,

no matter how many times you do it,

you go up on your flight, you can't get complacent,

and you always need to be thinking,

what have I thought of

or what haven't I not thought of,

and make sure everything is where it should be

and everything's in place.

There's no second chances.

Helicopter ready, it's time to get suited up.

These aren't your regular flight suits.

To prevent electrocution, Ryan and Vinny

must wear protective overalls that have steel thread

woven into the fabric.

These suits here, part Nomax and part steel.

They have little steel strands woven into them.

In theory, this thread conducts electricity

more efficiently than flesh and bone,

so when Ryan touches the cable,

power flows around him, not through him.

(intense music)

This is definitely not a beginner's job.

There have been inexperienced guys

that have wanted this job,

and I don't think they understand the risks of it.

I am an experienced helicopter pilot,

and I question myself some days

thinking, why am I doing this?

This is unbelievable.

(intense music continues)

All right, we got a timer ticking.

All gauges in the green, lights are all out.

All right, let's lift. You good?

Nice and clear on the tail.

(dramatic music)

How you doing out there, you all set?

Yes, sir.

How do you feel buddy?
Good.

Nice and loose, come on.

It's now 9:00 a.m.

Getting to the job site will take 45 minutes.

Ryan and Vinny will have to work fast

to complete the spacer change

before the weather closes in.

If the wind begins to gust,

it will make an already dangerous task deadly.

Teamwork is crucial.

Biggest key up there is communication.

Constantly talking to Vinny.

Any movement that I make in that aircraft,

Vinny will feel, and it'll affect the helicopter.

There's very small margin for error.

We work very closely together.

I need to be able to understand what he's doing.

And if I'm not aware beforehand, it becomes a surprise,

and surprises aren't good.

All right, you all set?

Yes, sir. Bring her in.

Before he can get started,

Ryan must electrically bond the helicopter

to the power line using a special wand

known as a hot stick.

Bonding on is one of the most dangerous stages

of the flight.

It's a rush, you know?

When you first realize what you're about to do,

you're about to bond onto 500,000 volts.

(electricity zapping)

You see the arc to the wand,

that makes me part of the circuit.

All right, we are bonded.

You don't feel it.

Once in a while when you're working on a wire,

you might get a little nip in the hand,

but it's not uncomfortable.

Electricity's going around you,

around the helicopter.

It's a rush.

Once attached,

electricity flows around the helicopter,

keeping Vinny and Ryan safe.

I trust Vinny with my life up there 100%.

Lift me a little bit.

Coming in, coming in.

See what this bad boy's got.

Ryan now faces a race against time.

(intense music)

With strong winds forecast, every moment spent

connected to the 500,000 volt cables

spells danger for the crew.

Ryan must work fast to replace the aging spacer bar

holding the lines apart before the weather

grounds the chopper.

Gonna zip this one down.

I'll get you a little bit higher.

I'm gonna give it a little yank.

Yup, fine. I'm ready for it.

While Ryan gets to work,

it's down to pilot Vinny to keep the helicopter

in a stable hover, centimeters from the live power line.

Wait, I'm gonna get you in the air a little more.

There you go.

Watch it above your head.

Yup.

One thing you really need to do

is keep calm and relaxed and on top of your game.

An unexpected gust of wind

could be devastating.

Wind is everything with this helicopter.

Definitely not any gusts, unexpected gusts

will make you climb or descend.

If the chopper touches anything else,

a tree or another power line,

Vinny and Ryan could be instantly electrocuted.

It takes every ounce of concentration to complete the move.

Hovering the helicopter next to the lines

is definitely some of the most challenging flying

you can do.

The inputs on the controls are thoughts.

There's not actual pressures, and definitely no movements.

You wanna go higher, just think it,

and you're starting to go higher.

With this helicopter, it's extremely responsive,

and it's very powerful, very maneuverable.

The new spacer doesn't quite fit,

and Ryan doesn't have the tools he needs to adjust it.

Yeah, we'll have to break off, man.

All right.

To keep weight down,

Ryan only has the bare essentials on board.

A hammer isn't part of his toolkit.

You wanna grab a hammer?

Hell, we'll get one.

The ground support crew has one,

but it will take too long for Vinny

to get permission to land.

To retrieve the hammer, he must carefully hover

a few feet above the ground

while it's transferred on board.

(electricity zapping)

See what we can do here.

I'm gonna give it some whacks, all right?

All right, I understand you're whacking it.

With the right tools, the job is soon done,

just as the wind starts to build.

Ready?

Take me away.

All right, taking you away.

Ryan and Vinny's daily battle

on the front line is crucial.

Without them, the system would break down.

Let's get out of here, pal.

And behind them, an army is at work

generating the power that flows down the line.

(exciting music)

Around the world, approximately two-thirds

of all electricity is produced by burning fossil fuels.

But that's beginning to change.

In the future, up to a fifth of global energy requirements

could be met by environmentally-friendly biomass.

Organic matter, such as wood or straw,

that is used as a fuel.

40 kilometers from London, Tilbury Power Station

used to burn coal, but in 2011 it was converted

to burn wooden pellets made from compacted sawdust.

It's now one of the largest biomass power stations

in the world, and a vital piece

of London's power infrastructure.

Dave Dyson is the station's engineering manager.

Tilbury produces about 800 megawatts

of renewable power.

That's a significant part of what London requires,

about enough to support 1.5 million homes.

It's 8:00 a.m.,

and Tilbury Power Station has a problem.

One of its three huge boilers has sprung a leak.

Every minute the boiler is out of action

threatens London's power supply.

Dave is under pressure to fix the tiny leak,

and get the massive furnace back on line.

The boilers, as you can see, are huge.

They're 15 stories high, 20 meters by 20 meters.

They turn 1,000 tons of water into steam every hour,

and the whole thing's a huge fireball.

To generate electricity,

pellets are burned in the middle of the boiler.

The heat produced turns water in the boiler tubes

into high pressure steam.

This steam spins a turbine that rotates a rod

covered with magnets.

The magnets are surrounded by a spool of copper wire,

and as it rotates, a magnetic field is created.

This causes electrons to flow, producing electricity.

A broken boiler means no steam and no electricity.

The engineering team has found the source of the leak,

now they need to repair it.

An experienced boiler engineer knows the sound

of a boiler, just by walking down the boiler

he can tell if there's a leak and where it is.

He knows the sound of it, he walks around it every day,

and he can detect a leak, determine where it is

just by the sound.

The boilers are the heart of the power station.

When they're working, temperatures inside

reach 1100 degrees.

A tough environment for the metal pipe.

There's approximately 240 miles of pipe

within the boiler, so it's not surprising

that we get the odd failure now and again.

(tool whirring)

The pressure is on Martin and his team

to cut out the burst section of pipe

and insert a new piece.

The most common kind of failure

in conventional power stations like Tilbury,

is a boiler tube failure.

These tubes operate in very severe hostile conditions.

So if they're not in the best condition,

they won't survive.

We're constantly trying to engineer

new ways of preventing damage,

of monitoring the boiler conditions

in a more effective way, to minimize the failures,

but with 240 miles, it's still pretty difficult

to do that every day of the week, every week of the year.

400 kilometers of piping

to keep in perfect working order

is an extraordinary task.

Until this section of it is fixed,

Tilbury is unable to deliver its full quota

of electricity to London.

The power station supplies London with electricity

via the National Grid, a network of power lines

stretching right across the country.

The grid is designed to cope with an occasional

burst boiler pipe, but if other stations

have a problem at the same time,

London could face a blackout.

It's vital Tilbury's other two generators keep working,

and for that, they need fuel.

These are the pellets that we burn in the power station.

This kilogram of pellets here

produces about two kilowatt hours of electricity.

That's enough to provide 90 cups of tea,

charge your mobile phone for the best part of a year,

or to power the average sized TV for about 16 hours.

Scale this up to meet the needs

of almost 1.5 million homes,

and Tilbury has to burn a staggering amount of pellets.

Ross Philips is part of the team responsible

for keeping supplies flowing.

Trying to explain to people the appetite

Tilbury has for wood pellets is difficult.

The sheer scale, the number of pellets we use

is mind boggling.

Ross depends on shipments

from all over the world.

In the long term, it may be difficult to source

the vast amounts of fuel Tilbury needs

from sustainable sources.

The general size of ship that we get in Tilbury

holds anywhere between 20,000 and 45,000 tons.

And that all lasts Tilbury no more than four, five days.

This vessel is en route

from Georgia in the USA.

It's carrying 6,200 tons of pellets,

enough to supply Tilbury for just 16 hours.

We currently burn around 450 tons of biomass every hour

when we're generating.

Over a year, that's enough to fill

Wembley Stadium four times over.

To unload, pellets are simply sucked out of the hold

by a machine that operates

just like a giant vacuum cleaner.

It's a never-ending cycle.

The problem is that you can't store pellets outside.

If they get wet, they become unusable.

Therefore, pellets are moved straight from the ship

into the station.

This supply and demand system

has a major drawback.

If the flow of pellets is interrupted,

the station could run out of fuel in just six hours,

creating a hole in the National Grid

that other stations would be forced to fill.

It's Marcus Nikola's job to monitor the pellets

as they travel along almost a kilometer of conveyor belts

into the power station.

The wood pellets are as dry as a tinderbox.

Fire is an ever-present danger.

There is a potential fire risk

from all the moving parts from our bearings and our rollers,

so everything has to be monitored

to ensure that there is no fire risk.

At Marcus' disposal are 76 CCTV cameras,

smoke detectors, and infrared cameras.

But he isn't just reliant on technology.

Basically, we always have an outside man

because as you walk around, you hear things,

you can see things.

We have all this state of the art technology,

but there's no substitute for a person out

walking the actual line.

And right now,

Marcus is in need of his outside man.

A conveyor belt has stopped, halting the flow

of pellets into the power station.

Conveyor 18, we've got a Hewitt trip.

Just investigate for me, over.

So we've had one of our conveyors go down,

conveyor 18 has had a trip on it.

That means now we've got no path at all

to the bunker house, so right now we can't move

any pellets from the ship to the station.

Ross must get the conveyor working quickly.

Without it, the power station will run out of pellets

in just four hours.

If we can't generate, less power will be available

for London to use.

The network of conveyor belts

contains several thousand moving parts,

but Ross is quick to spot the problem.

It looks like there's been a pellet spillage.

I can't see any obvious obstructions.

There's any number of things that could cause

a spillage like this, a foreign object,

or a piece of tram coming off the boat

could cause a blockage, which could then cause a spillage.

John, I've reset the Hewitt trip here,

could you confirm that it's available now, please?

Yeah, 18 conveyor now available.

Sorted out.

Production resumes,

but hours into the afternoon shift,

Marcus Nicola calls on Ross for a second time.

Conveyor 18 is down again,

and the problem appears to be far more serious.

I found the problem on conveyor 18.

One of the return rollers is broken.

You can see a little bit of the debris here

on the ground.

And it's come loose, it's come detached

from the attachment on the side, here.

Until the broken roller is fixed,

Tilbury will have to rely on just a single conveyor belt.

As a result, this belt will probably be out of action

for a good four, five hours,

which means we're down to just the one belt now.

But with that one belt we can keep going.

It does mean we're slightly more vulnerable.

As long as we don't get another problem with the other belt,

we're all right for now.

But it's cutting it close.

Despite only one conveyor belt working,

fuel supply resumes.

Inside the broken boiler, engineers have removed

the burst section of pipe.

It was probably original tubing

from when the boiler was built.

It's overheated quite quickly

and has just become too soft to take the pressure,

and it's burst, and you can see

with the effect we've got here.

Before they can repair the boiler,

Martin needs to inspect the remaining pipe.

This is a pipe camera.

It lets me look up small ball pipework.

Making sure that we've cleared all the damage.

I can see that that end's clear.

So is that, so we've cleared all the damage

from the tube.

Its replacement is seven millimeters thick,

strong enough to withstand the ferocious heat

inside the boiler.

You could make them thicker,

and make them stronger in some respects,

but that would simply make the heat transfer poorer

and possibly introduce fatigue failures

because they'd flex less easily.

It's finding the right size of material,

the right material itself to operate

in the conditions in which it's been asked to.

The weld has to be perfect.

The slightest fault will quickly lead to another leak.

Hi Ty, it's Martin,

just to let you know we finished welding in the boiler,

give us an hour to clear it down and it's all yours.

Job done.

But it will take another four hours

for the boiler to produce enough steam

to spin the generators and produce electricity.

Biofuel powering London is just

one technological breakthrough in the battle

to keep electricity flowing.

Electronic billboards, data storage,

even mobile phones are all pushing up demand

for electricity in our cities.

Now, an army of engineers is trying to wean these cities

off electricity produced from fossil fuels.

They are looking for new ways to generate clean power

using unlimited natural resources.

In parts of the world with clear skies,

that means power from the sun.

(intense music)

In the Nevada desert, technical director Brian Painter

and his team face the biggest challenge of their careers.

It's technology that was developed

by literally rocket scientists in the middle '80s

and this is the first commercial venture

for this technology.

They are building a groundbreaking

solar thermal power plant,

and it must be finished in less than six months.

Crescent Dunes Solar Thermal Power Plant

doesn't use conventional solar panels.

Here, over 10,000 mirrors called heliostats

are being built around a 195 meter tower.

The heliostats will focus the sun's rays

onto a special receiver at the top of the tower.

This concentrated solar energy will be used

to create steam that will produce electricity.

When you're driving through the heliostat field

it's just like driving through a big mechanical forest.

It's steel, it's computer controlled systems,

and it's glass.

So far, just 1400 of the 10,000 heliostats

have been installed.

Eventually, they will cover

over five square kilometers of desert.

The project requires so many

that a temporary factory has been built onsite.

It churns out 80 heliostats per day,

thanks to manufacturing processes

lifted straight from an automotive plant.

Every one is designed for a specific spot

on the desert floor.

Getting them all to work together

creates a mammoth headache for Tim Connor.

We have to go through this initialization

and calibration for each individual heliostat,

all 10,348, before they can be operated

as a collector field.

Each heliostat consists of 35 mirrors

or facets, every one of which must be perfectly positioned

to focus the sun's rays on the top of the tower.

Each heliostat has a focal length,

and each individual facet is slightly curved

based on the distance it is from the tower

and the receiver.

What I'm doing here is running the heliostat

through the range of motion for the elevation,

and we take it from the plus 90 to the minus 10 position.

Some of the heliostats are more than

half a kilometer from the receiver.

What you see now is since the concentrated energy

from the single heliostat,

you can imagine the intensity, the thermal intensity

on a receiver with 10,348 heliostats

focused all at one time.

The amount of energy with all the heliostats

pointed at the receiver would melt aluminum

in a matter of seconds.

Once the sun's rays hit the target,

the precise position is recorded,

and the calibration is complete.

What happens once the sun's rays hit the top of the receiver

makes this power station unique.

The sun's energy is used to heat molten salt

to over 530 degrees Celsius.

The salt that we're using the system

is not your regular ordinary table salt.

It's only found in a couple places in the world,

and its value is in its density

and the ability to store energy.

Salt is heated by the focused power

of the sun.

It is then piped into a storage tank

where it retains heat for up to 10 hours.

When power is needed,

the molten salt is pumped to a generator

where it boils water, producing steam.

This steam spins a turbine, generating electricity.

As the salt cools, it is pumped back

to the top of the receiver to be heated again.

Right now we're standing in the middle

of the hot salt tank.

It's a very large tank, 140 feet diameter,

40 feet tall, it'll hold 70 million pounds of salt

that is 1050 degrees Fahrenheit.

The tank acts like a giant battery,

storing the sun's energy until needed.

Crucially for a power station fueled by the sun,

this means it can produce electricity

long after the sun has set,

and even when the sky is cloudy

it can generate electricity reliably,

day in and day out.

We can actually collect the energy during the day,

and then we can operate whenever we want.

So essentially electricity collection

and electricity generation are two separate processes,

so the utility here in Nevada

is looking first to generate reliable electricity

well into the evening hours, 12:00 noon to 12:00 midnight.

Today, a key piece

of the steam generating plant

is being lifted into place.

The drum weighs in at 95 tons,

making the lift a difficult and potentially dangerous task.

To withstand high pressure steam,

the drum is made of five centimeter thick steel plate.

If it falls, it will destroy the structure it sits on,

and set Brian and the team back by several months.

What's that?

Right now we're raking up a steam drum.

This is pretty well the last heavy lift

we have on the site.

We're gonna set it up on top of the steel structure

on top there.

We don't want anybody hurt.

We don't want any equipment damaged,

and so there's a lot goes into this lift.

A lot of planning and preparation,

to make this lift happen.

Installing the drum is an important milestone.

This vessel right here, it's the last part

of the process of making steam.

The steam travels through the piping from here

to the steam turbine.

Another piece of this complex jigsaw puzzle

is lowered safely into place,

bringing Crescent Dune Solar Thermal Facility

a step closer to producing the electricity

Las Vegas can't live without.

When the switch finally goes on

it will be a tremendous rush for everybody.

I mean, we've been building for years

to have this technology really take hold,

and to see the facility come together is great,

but once we turn that switch on,

it'll be fabulous.

When complete, the plant will provide

110 megawatts of power, enough for 75,000 homes.

It might not rival the 1.4 million homes

powered by London's biomass burner,

but in theory, this technology could supply

all the electricity Las Vegas needs.

When you're looking into the future,

cities like Las Vegas and Los Angeles

are gonna be utilizing a tremendous amount

of solar energy for their power needs,

and this project can help meet those future requirements.

(light music)

But not everywhere

gets as much sun as Las Vegas.

All over the world, new ways of generating power

are being developed using local resources.

In many places, that means wind power.

There are now 225,000 turbines

spinning in 79 countries,

and more are being built every year.

18 of them are at Middlemore Farm at Northumberland.

The turbines here will soon produce enough electricity

to power 27,000 homes.

It's a tiny number set against Tilbury's 1.4 million,

but by 2020, over 15% of London's electricity

could come from the wind.

We chose this site because it's windy,

and we'll make lots of energy out of it.

And it's also quite close to the grid

so we can export the electricity to it.

The power produced here

will be exported to the National Grid

that supplies London with electricity.

We started at the end of January

and we've got about 14 turbines up at the moment,

just building the 14th one,

and we expect to finish it in about two or three weeks.

To meet this deadline,

the construction team need calm weather,

and this can be hard to come by on a wind farm.

It's a paradox of the industry

that the places where you actually want to operate

the wind turbines, because they're windy,

then that gives you a problem in construction,

because when it's too windy we can't actually build.

The crane can't lift.

Each turbine arrives on site

in seven pieces.

The heaviest weighs 77 tons.

Lifting pieces this big 80 meters in the air

is a task that requires one of the largest cranes

in the UK.

But even it can't lift in windy conditions.

With so much at stake, site manager Dave Whittaker's

first job is to check the weather.

Well, looking at the forecast today,

we've got some very high winds coming.

It's forecast to get a lot worse,

so what we usually do is

go down to the crane and see what the crane reading is.

If the wind speed is too high on the crane

the team can't lift the turbine.

The final call falls to crane driver, Seamus Camidy.

If the wind catches that, it has a pendulum effect,

and it can either turn around or start swinging,

and if it starts swinging,

there's nothing gonna stop it, you know?

I'm getting 16 or 17 meters pushing into the crane

so it's not safe at the minute.

Okay, just safety reasons.

We'll just call it then, today.

Yeah.

It's a serious blow to the schedule.

Finishing in three weeks time will be impossible

if the bad weather continues.

Next morning, the wind has taken a break.

Dave and his team need to make up lost time.

This looks good, mate.

And weather for today,

let's just get it done.

The plan is to lift the second

of three tower sections, and stand it on the first.

If we get our perfect wind conditions in

we get enough preparation work done beforehand,

the actual lifting procedures,

we can erect the turbine in one day.

Conditions may not be perfect,

but they are good enough for the lift to go ahead.

(soft tense music)

Slowly, the 24-meter long section is lowered into place,

and bolted down from the inside.

The wind is beginning to pick up.

The team can't risk another lift.

With two sections complete,

the structure can be safely left for another day.

It's extremely windy today,

and it's above our legal limits and it's dangerous,

so we don't take any chances.

With further progress

dependent on good weather, the team's chances

of hitting their deadline diminish by the day.

When we have wind days it is really frustrating

because we're here to build a wind farm,

and due to the wind, we're set back a day with the lift,

and that puts pressure on the guys

so it does get really frustrating,

but that's part and parcel of building wind farms.

While wind stops play at Middlemore,

engineers at another new wind farm

are making the most of good weather.

Bradwell-on-Sea's 10 turbines

will generate enough power for up to 12,000 homes.

Today, turbine number nine is due to be completed.

Lifting this piece is technically difficult

and needs two cranes to work together.

The larger crane has to lift the 76 ton section

from horizontal to vertical,

and then raise it 28 meters in the air.

To prevent the bottom of the tower getting damaged,

the second, smaller crane,

has to lift the base of the tower

clear of the ground at the same time.

Once in place, the tower sections are under

massive side-on pressure from the wind.

They have to be joined together by 84 bolts,

each 3.5 centimeters thick.

We're just getting at the top section on.

Once that gets on, then it'll take the guys

maybe half an hour, 40 minutes,

to get the bolts in and stuff.

Next up is the nacelle.

This 69-ton capsule sits at the top of the turbine

and houses a generator and gearbox.

Just like at Middlemore, as engineers prepare to lift,

the wind begins to pick up.

Yeah well we started this morning,

we were here for eight o'clock like we were getting to be

two three meters per second

and at the minute there it was gone up

to maybe seven meters per second, eight meters per second.

Having put the third tower section on,

the team must lift the nacelle today.

Its weight will stabilize three sections of tower

and make it safe to leave overnight.

We have to get the nacelle on top of the third section,

otherwise your tower will start to oscillate

you know, if it's left and the wind speeds pick up.

The nacelle is the size of a bus.

If the wind swings it into the crane,

both will be destroyed.

The team daren't risk lifting the turbine blades.

That job will have to wait for the morning.

We've got the nacelle up as you can see yourself,

we've got it up this evening there.

The wind was starting to pick up, but we got it up.

(light uptempo music)

At a just completed turbine

on the other side of the farm,

project manager Adam Potter is in need of some wind.

And the final process for commissioning

is to actually see whether it generates electricity,

and the best way to do that is simply by turning it on.

The UK's newest wind turbine

slowly comes to life.

And now we can see that the turbine

is generating electricity,

the numbers are gradually increasing,

eventually it will reach over 2,000 kilowatts,

and that's enough to power 1200 homes.

Wind power looks set to play

an important role in securing London's supply of energy,

but it can't entirely replace the need

for electricity produced from fossil fuels.

You couldn't just have wind farms in isolation

because when there is no wind,

you need to have other sources of power.

The key to it is that when it is windy

then you're reducing the amount of power

that you need to generate from other sources,

such as fossil fuels.

Across the world, electricity use

will increase 85% by 2040.

Many of the networks that carry this power

into our cities are near breaking point.

Radical solutions are needed to keep the power flowing.

London's population is expected to increase

by one million in less than 10 years.

With more and more power flowing into the capital

from power stations all across the UK,

the National Grid faces the biggest challenge

of its 50 year history,

and to secure London's electricity supply,

engineers are battling to dig 32 kilometers

of tunnels beneath the capital and rewire the city.

Garreth Burden and Richard Spencer

are overseeing a crucial part of the project.

The increase in demand and the aging network

essentially means what we're doing here

is rewiring the whole of London.

(uptempo music)

The existing network

runs under the city's roads.

Digging it up and replacing old cables

would bring the city to a standstill.

The solution, build an underground electrical superhighway

to carry upgraded power lines into the heart of the city.

This is the most ambitious and significant project

that the National Grid's undertaken

probably since they built the original network.

The grand plan is to dig 32 kilometers

of tunnels, connecting substations across the city.

But beneath London lies an existing subterranean network

of vital infrastructure.

Tunnels water of deep, deep water tunnels,

you obviously have the London underground network,

you have some network rail tunnels

as well as other deep infrastructure,

such as cross rail.

It's like spaghetti junction for tunnels,

London, in some regards.

The miners can't afford to get it wrong.

Accidentally tunneling into a busy underground line

would be a major disaster.

Two teams of miners are working around the clock.

Each 12-hour shift begins with an underground journey

deep beneath the city.

(exciting music)

(brakes squealing)

We're currently 30 meters under the ground

where we're sitting right now.

We've journeyed for approximately 10 minutes

and we're 1500 meters in.

To dig this tunnel, engineers are using

100 meter long tunnel boring machine, or TBM,

nicknamed Evelyn.

At the front of the TBM,

a cutter head armed with chisel-shaped teeth

slowly rotates.

As the machine advances forward,

the cutter head slices through soft London clay,

which falls into waiting wagons.

To prevent a deadly collapse of the clay,

rings of concrete tube are fitted

to create a secure tunnel wall.

Engineers like Joseph Gibbons can't afford

to make mistakes.

One of them plates come down there,

there's 900 kilos, nearly a ton weight,

like it's a lot of weight.

You have no hope against it if it comes down.

Like there's no room for mistakes.

Each complete ring extends the tunnel

by 1.2 meters.

Completing as many rings as possible every shift

drives life underground.

Takes us roughly five to six minutes

to be able to excavate a big enough proportion of ground

to build the next ring, so we've got an excavation

and build cycle around 15 minutes approximately.

We aim to build as many as four rings in one hour,

and carry that through a 12-hour period,

so we can get anywhere between 30 and 40 rings

if we're really working flat out.

The record is 48 meters of new tunnel.

For this to happen, the entire system,

including cranes and trains that bring material

in and out of the tunnel, has to run like clockwork.

The minute logistics falls down,

your tunnel falls down and you lose production

for the day or for the time that's happening.

Effectively, it's a giant logistics project,

and you can see trying to balance

productivity of the machine whilst also getting

materials in and out of the machine to service it.

Every link of this production chain

must succeed.

Right now, a brand new section of tunnel has been excavated,

leaving the train that services the boring machine

short of its final destination.

If the rail track doesn't keep up,

this critical cycle would grind to a halt.

If we don't do the railway track,

then we can't feed the TBM with the concrete rings

that we need to progress, so the guys here,

we need to feed the machine all the way

so this railway track's a crucial part of that.

But constantly building extra meters

of rail track is tough.

The track must be stable and secure,

or there'll be a risk of derailment.

So now Dominic's gonna bolt down these sleepers

to ensure the security of the rail

and the right spaces, et cetera.

(intense music)
(tool whirring)

So far, Evelyn is 8.5 kilometers

into her 20 kilometer journey,

and is currently 30 meters below Wimbledon

in south London.

It's vital the tunnel follows the carefully mapped route,

weaving its way around existing cables and tunnels.

On this specific job, we've come within five meters

of the London underground Bakerloo line,

so above us was the London Bakerloo line.

If you stood in the tunnel, you could hear those vibrations

and those trains passing by.

And whilst Evelyn bores her own path

through underground London,

the excess clay mounts up at an astonishing rate.

The material that we're excavating in here,

the London clay, that's governed

a lot of the process for the entire job,

so this allows us to use the particular tunnel machine

that was specified for this job.

The only thing we may come across

is the old clay stone from compaction

over the millions of years that it's been laying there.

So this is coming straight from the base,

taken directly out of this skip.

The train will journey approximately 10 times

in and out of the tunnel in one day,

helping to take full skips of clay up to ground level.

(uptempo music)

People take power for granted, really.

We're here delivering the systematic infrastructure

that can allow that to happen at the flick of a button.

After a grueling shift

in hot, cramped conditions,

the team has laid 30 rings, or 36 meters of new tunnel.

We're all happy that the shift are going home now safely,

but it doesn't stop for long,

after about 10 minutes the next shift

will be in there for the night shift,

and then the whole process will be repeated again.

Projects like this will ensure power

continues to flow into our cities,

allowing engineers the world over

to keep the lights switched on.

(exciting music)
(crowd cheering)

It's 10:00 p.m. in Las Vegas,

and on Freemont Street, this means showtime.

The world's largest LED screen consumes over 9,000 kilowatts

of electricity every night.

It's all operated from this control room.

From here, a complex network of fiber optic cables

transmit signals to each LED light.

The video is played back by eight media players.

Each player plays a section of the canopy,

because the canopy is separated into eight sections,

but once it's all together and it plays in sync

it looks like one seamless video.

(exciting music)

It's Chris Bell's job to ensure

all 12.5 million LED lights are working.

All right, so right now on the video screen

it looks like two LED circuit boards have gone out.

It's gonna require me going into my lift,

going up to them, and replacing both of them.

(energetic rock music)

It's close to midnight,

and Chris' work is just beginning.

(energetic music continues)

The reason why we do the maintenance

at 2:00 in the morning on the video screen

is because we can't see it during the day.

As light comes through, the screen,

and actually washes it out.

Every one of the half a million circuit boards

must be kept in perfect order.

And now that those circuit boards

have been replaced for the next show,

the public is gonna see a perfect screen.

(light music)

Cities the world over

rely on highly skilled engineers, crane operators,

even pilots, to keep the power flowing.

Without this hidden army of workers

toiling around the clock,

transport networks, communication systems,

lights, even hospitals will all shut down.

(helicopter whirring)

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