Electricity Across Oceans: Is HVDC the Future?

Published 2023-07-11
How can we connect power grids across long distances or across seas and oceans? The answer is high voltage direct current, or HVDC, interconnectors.

In this video, I’m going to explain how these differ to regular AC, alternating current transmission, the recent technology advances that are causing HVDC interconnectors to start popping up all over the place, and what challenges remain to be solved if we are going to connect places as far flung as Europe and North America.

00:00 Intro
01:08 Why do we want to connect different grids?
01:35 The classic question of AC vs DC
02:29 Types of Transmission Line Losses - Resistive, Inductive and Capacitive
04:19 The Different Layers of an HVDC Cable
05:20 HVDC Projects around the globe
05:25 ElecLink
06:23 North Sea Link
07:13 Basslink Interconnector and Marinus Link
09:15 Sun Cable
09:38 Xlinks
10:20 Technological challenges for these projects
12:15 The other, bigger challenge - Politics
13:12 Outro

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The Engineering with Rosie team is:
Rosemary Barnes: presenter, producer, writer
Kevin Irman: research, calculations, assistant editor
Javi Diez: editor www.linkedin.com/in/javierdiezsuarez/?locale=en_US
Cowritten with John Bone

All Comments (21)
  • @Electroblud
    Hey, high voltage test systems engineer here. This is an awesome explanation video! I love the representation of HVDC you are doing here. Economic reasons and technological feasibility have a great balance here. You said the cables have a high capacitance due to their proximity to the ground or water. 4:10 While this is technically not wrong, the reason for the high capacitance is their outer, grounded sheath! These cables are under ridiculously extreme electrical stresses compared to open air transmission lines. Their insulation is quite high tech, but the sheath is a key feature. It homogenises the electric field inside the insulation, greatly reducing stress. Also, it keeps the electric field inside the cable, so the outside is (nearly) field-free. Very important as to not disrupt all kinds of stuff going on outside the cable.
  • @hmw-ms3tx
    Where I live (Manitoba, Canada) we have three HVDC transmission lines in operation. Most of our power is from hydro and the vast majority of it is produced in the northern part of our province on the Nelson River. Most of that power gets consumed in the southern part of the province and back in the early 1970's two HVDC lines were run north/south. These were known as Bipole 1 and Bipole 2. These two line were run side by side in the same right of way and in the 1990's a tornado knocked both of them down. In the early 2000's it became necessary to run a third line and for security reasons (both weather and terrorist) it was decided this third line should be run down a different route. This is were the story veers from engineering to politics. The best technical route (i.e. shortest) was down the east side of the province. However, the government of the day decreed that it would run down the west side of the province. No amount of reason would sway them and the engineers in the project remained quiet for fear of losing their jobs. The retired engineers from the original Bipole projects had nothing to worry about and there was a constant barrage of reason and logic aimed at the government in the opinion section of the newspapers of the day. They christened it the "Western Manitoba Heater" and pointed out that the extra 200 MW of line losses over the east side route would consume all of the power of the most recently completed dam. None of it worked and Bipole 3 was built on the west side for considerably more money than the east side route and will now lose an extra 200 MW in perpetuity. It's no wonder you see so few engineers in politics.
  • @treecrusher
    We also have an HVDC across the ditch in NZ connecting hydro in the South Island to the population centres in the North Island.
  • @bigutubefan2738
    The map showing your Trans Atlantic 'sub sea' cable route, omits the Republic of Ireland, through which your cable must go, if it doesn't take a huge detour.
  • @kjlovescoffee
    Wouldn't it make more sense to connect the UK to Faroe, Faroe to Iceland, Iceland to Greenland, and Greenland to Canada? That avoids many of the problems associated with super long cables, as well as avoiding some of the deeper seas. For example, From St. Ives in the UK to St. Johns in Canada (the shortest possible stretch), the cable would be over 3,000km long and have to be over 4.7km deep in some areas - most of it 3km or more. By comparison, from Thurso in Scotland to Kirkjubomururin in Faroe (415km, depths mostly in low 100s, with the middle dropping to 1km), Eioi in Faroe to Faskruosfrorour in Iceland (450km, depths mostly below 500m), Isafjorour in Iceland to Kulusuk in Greenland (640km, depths mostly below 600m), and Narasarmijit in Greenland to West Bay in Canada (1000km, of which around 800km drops to 3.5km but avoids the mountain range down the middle of the Atlantic. Add around another 800km between Kulusuk and Narasarmijit around the coast because it doesn't look like Greenland have an electricity grid, and I don't foresee anyone building HVDC across the landmass. This seems a lot more achievable, not to mention cheaper, than trying to lay a cable straight from the UK to Canada, and adds the benefit of Faroe's hydro and Iceland's geothermal along the way. Both, as well as Greenland, could probably turn themselves in to major energy players, with landscapes highly suited for hydro and pumped hydro. Well, in the summer, at least!
  • @Mladjasmilic
    Electrical engineer here: Only benefit of AC is cheap and efficient change of voltage inside transformer. Now, with modern DC-DC converters, they are almost as efficient. Benefits are: Grid does not have to be in synch any more, as all is DC, so whole world can be connected. Power routing is easy, as you need to have a little adjustment to direct flow of power, by boosting voltage a little on power line. Efficient home solar instalation, as you would not need to convert it from DC to AC for appliance use and just use 240V solar battery (or central tap 120-0-120 in split phase system). Most device in home can run on DC power supplies: Any swtich mode power supply (chargers, PC power supplies) Stoves and other resistive heaters (like boilers) Most LED and all incadesent lights Devices that can be adapted: Any device with universal motor (vacuum cleaner, blender), but you would need to give up speed control or change the circuit Inverter air conditioners and fridged Devices that would not work on DC and need am inverter to work: Anything with old iron core transformer Anything with an induction motor (fans, pumps) Anything with a dimmer circuit (ligjts, vacuum cleaners) Clocks dependent on grid frequency
  • @NickCohn
    Always wondered why DC was being used for these long links while most long distant lines are AC. Thanks for the explanation!❤😊
  • @bigboy9983
    600 million for eleclink? That’s how much the feasibility study would cost in Australia
  • @barryhamm3414
    Sadly I have but one thumbs-up to give your excellent video
  • @keithwhite2986
    I had not realised my physics was so rusty, thanks for the refresh 😃
  • @jylfarm1964
    Since 1992, Hydro-Quebec already operate a 1500 km of DC line. They are looking to get many more of them online soon. The current line is transiting about $1M in electricity, every day. Regarding politic, it already a problem for Hydro-Quebec (Canada). The state of Vermont (USA) is dependent on HQ. Furthermore, The state of Massachusetts (USA) often consider that it will be imprudent to get more electricity from Quebec. New-York city is also VERY Reliant on HQ. HQ already supply some electricity to Ontario (Canada). All in all, if HQ were to shut down the delivery of electricity to New England, the NERC NPCC regions will likely crash. That the reason HQ looks at Europe. HQ is 94% Hydro. It does want to develop the WIND resource too. So, with Europe, what HQ will like to do is become the"BATTERY" where it does purchase electricity cheaply on the European market... and resell some when the sun is not shining or the wind not winding enough. HQ has an impressive amount of dispatchable electricity with Hydro.
  • @nas4apps
    For years now, Norway and The Netherlands are connected as well ... North Sea. The Dutch also have an energy platform island in the North Sea, this allows connections with sea based wind farms (windmills connect to the platform, operational already!). The platform provides an opportunity to connect with the UK grid. Another Danish - Dutch platform will be built for more Dutch and Danish wind farms and to connect Danish and Dutch grids. Sea based connection platforms can be the interconnection nodes in cross sea networks.
  • @CryptoKrill
    Fantastic video, plenty of information which is easy to understand and no in video ads. I'm going to show my daughter your videos as she's in high school right now and i've shown her engineering videos for a few years now and she's quite keen on becoming one and I think you'll be a real positive influence on her :)
  • @paulcummings55
    Excellent video with a good explanation of DC vs AC line transmission for this non-engineer- thanks!
  • @jimparr01Utube
    Yes, geopolitical insecurities are likely to become more and more important issues to factor into undersea HVDC. While battery storage (from pumped hydro to various cell chemistries) is seemingly more expensive, I believe the cost/kWHr storage will abruptly fall year by year in the next half decade as newer and more cost-effective stationary storage plants come on line around the globe. Furthermore, it is MUCH easier to use such storage to smooth peak-demand on grids locally. And last but not least, the massive and enthusiastic trend for home owners to go solar and also contribute to virtual power plants has been proven in the UK to remove massive stresses from ageing and (currently - no pun intended) inadequate electrical grid structures. B.T.W. Seriously clear explanations in this one Rosie. Thank you.
  • @blubberblubb
    Love the new production setup. I hope this upgrade doesn't cost a fortune, sure seems professional and very enjoyable to watch!
  • @elijahparker1789
    This was an awesome video! I remember my Power Engineering professor talking about this stuff a year ago. It seemed like such a cool idea, but I never even thought of its potential to unlock renewable energy. So cool that this is happening!
  • @johnchapman1903
    Very nice summary Rosie. In my view, you've got the level of detail exactly right.
  • @mikemellor759
    Fascinating insight into the financials behind HDVC - thank you. 🙏