This is an undersea cable. You’ve probably heard of them as they’re
used to transmit most of our internet traffic.
But this one doesn’t bring you your precious data — it’s even more important than that.
These cables share energy between countries and this one, stretching from the UK
all the way to Denmark, is going to be the longest ever constructed.
Yes, this does involve construction — and a lot of it.
Several have already been built and there are more planned all over Europe, a place
which could soon become home to the world’s first super grid.
That’s a system where green energy is circulated all over a continent,
depending on where and when it’s needed and you’re about to see why it makes a load of sense.
Renewable energy may be the way forward for our planet, but it has a bit of a problem.
What happens when the sun isn’t shining, the wind isn’t blowing,
or if there’s a sudden spike in demand?
Where do we get that extra energy from, especially when we’ve done away with fossil fuels?
And what about countries that aren’t able to install gigawatts of solar power,
build wind turbines all over the place or construct massive hydroelectric dams?
The answer could very well be these — interconnectors.
They’re high-voltage cables that allow two or more countries to link their electricity systems.
Instead of everyone hoarding their own energy, interconnected countries can share power between
them, make money from any excess and help ensure there’s always enough to go round.
There's a value for power in one country and a value for power in the other,
which is historically set either by the patterns of demand — what you're
using the power for — or the patterns of generation and how you're making the power.
Tom Edwards is an Energy Modeller at Cornwall Insight,
which provides research and analysis on energy markets.
So, for example, France sits in the heart of the European
energy landscape and because it's got lots of nuclear power, which is very cheap to operate
but expensive to build, they have a surplus of power, and they like to send that across to other
markets because those are the markets that are generally burning gas or coal.
Unlike a gas pipe, which only flows in one direction, interconnectors are a two-way street,
and can distribute energy generated using completely different methods.
Take the North Sea Link — it’s a new 720km cable between the UK and Norway
with a 1,450MW capacity. That’s enough to power around 1.4 million homes.
Since construction finished back in October 2021 the UK has direct access
to power originating from Nordic hydro plants.
In return, if the Norwegians want to inject some more carbon-free juice into their grid,
they’ve got energy from Britain’s vast offshore wind network in reserve.
Right now, it’s the world’s largest subsea interconnector, but not for much longer.
Work is underway on a 765km hook-up between the UK and Denmark called the Viking Link.
Fear not, my fellow Brits,
the Danes aren’t gearing up to send more rampaging Norsemen to our shores.
At least we don’t think they are.
This time they’ll be shipping over something more
favourable — clean energy that again mostly comes from wind.
Now, we’re only a few hundred miles apart,
but the UK and Denmark don’t often experience high winds at the same time.
So, if the wind dies down in the UK,
there’s a good chance the turbines are still turning across the North Sea, and vice versa.
Denmark has been trading wind power with The Netherlands like this
since 2019, when the COBRAcable was completed.
All of this increases the chance there will be some kind of renewable energy on tap,
whether it’s generated at home or abroad, and the idea will only grow as
more connections are made between countries with different weather and power systems.
In the future when we've got hopefully lots of low-carbon
generation, which should be cheap to operate but expensive to build,
it’ll all be very reliant on what the weather patterns are across the continent.
It's going to be really important to have an interconnected system in that way,
partly because we're going to be more reliant on these variable energy sources.
Already, more than a dozen interconnectors
have been fully commissioned or are under construction around the North Sea alone.
The idea is energy becomes more affordable for everyone and we
could all do with our bills coming down right about now.
Interconnectors give access to a wider pool of energy sources, meaning more competition and,
in theory, lower prices.
But hang on a minute, how does this all work? How is it possible
to transmit so much power over such a vast distance using just cables?
Well, these cables are a bit more robust than the ones we use to charge our phones
and the things they connect to are a little more complex too.
In the case of other long undersea connections like
the new 623km NordLink between Norway and Germany,
two converter stations were built at either end, which are hooked up to the countries’ power grids.
To send electricity through the cable, it has to be converted from AC to DC
power - that’s to try and keep any energy loss during transmission to a minimum.
When it reaches the station at the other end it’s converted back to AC
power and is ready to enter the grid.
On NordLink, special vessels were used to lay the cable, which weighs up to 70kg per metre
and consists of two parallel strands — for the positive and negative poles.
Because it had to be buried at depths of up to two metres,
a jetting sledge — that’s like an underwater plough
pulled along by the boat — was used to dig a trench and bury the cable at the same time.
When they reached the shore, a combination of offshore platforms and microtunnels brought
the cable onto land before it was pulled through and connected to the stations.
Many of Europe’s interconnector projects are built like this but not all of them,
and the reason is pretty obvious when you look at this map.
Most of the continent’s neighbouring countries aren’t separated by water so
if they want to link up their energy networks, boats aren’t that useful.
You might think making overland connections is a lot simpler,
and it often is, involving little more than transmission lines.
It's historically easier to connect countries across a land border.
There are reasonably good connections between Germany-France, Germany-Poland.
There's constraints across those as well, so it's not like they're perfectly connected.
Doesn’t mean it’s always easy, though.
That small matter of the Pyrenees between Spain and France meant the
two countries had to dig over 60km of tunnels - but the new
interconnector doubled the amount of electricity they can exchange.
Not only has it meant a greater flow of renewable energy between the two countries;
it has also helped ensure there’s enough power to run high-speed trains on the Spanish side.
The benefits to all this seem pretty clear, but are there any downsides?
Are these connections completely reliable and what happens if something goes wrong?
One incident in September 2021 involving the link between France and the UK
proved this type of infrastructure isn’t entirely bulletproof — or should I say fireproof.
A blaze at the IFA converter station
in Kent forced it to shut down and it could take two years to fully restore.
It led to energy supplies becoming a lot tighter than expected ahead of the winter
and a rise in bills.
Every large piece of infrastructure is prone to risk.
The key thing about interconnectors is they’re so big they’re actually a
risk to the stability of the system when they fall over.
The North-South link to Norway is now the biggest single generator
or point at which power can enter the system.
What's the single biggest thing that can go wrong? Well, it's now this really big
interconnector that's bigger than even the biggest nuclear power station that we have on the system.
In a future where more connections are in place though,
outages like this should be easier to address. Because if you lose one
source of incoming power, there would be more to fall back on.
And that’s exactly where things are going — particularly in and around the EU.
In 2019, there were 82 connections between the EU
and ten neighbouring countries, spanning 22 borders.
But it’s just the start. The EU wants to achieve 15% interconnection by 2030.
By that point each country will have the infrastructure to export at least
15% of the electricity it produces via these links.
Eventually this could lead to what’s been dubbed the European SuperGrid — where every country is
fully interconnected not just to themselves, but also places like North Africa and Turkey.
No pressure to make sure we all get along.
Now, there are other projects worldwide that are set to break new records, like Sun Cable’s
plan to connect Australia and Singapore and EuroAfrica, linking Greece, Cyprus and Egypt.
But for overall scale, Europe’s energy strategy will take some beating
and is likely to prove that in the future we’re better off connected.
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