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Comment by londons_explore | Hacker News Reader

I believe big cables will the the future... +-3 million volts and 30,000 amps DC makes a pair of cables each 2 feet thick which can deliver enough power for the whole of the UK, and then take that power from the equator to the north pole while losing only 5%.

The cable itself is expensive to make and hard to install, but I believe we will put cablemaking equipment onto a ship, and sail it at 1mph all the way from the equator to northern europe, with other ships bringing shipments of copper, steel, and polymers to keep it going.

The cable will be fed by lower voltage feeders, and voltage conversion done by stacked MOSFETS (600V MOSFETS, 5000 of them stacked, and all encased in polymer - at these voltages, air isn't a good enough insulator unless you have absolutely huge buildings.) Each stack can add or remove 300 megawatts of power from the cable - so you need a couple per powerstation or city

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This sounds like an in pipe(/cable) dream... First, you need that pair of cables for the UK (assuming your math and physics work out). Then you need at least 10 times that for the rest of Europe. Then we have all those cables in the water, in different places at the coasts of sea bound countries. We need to then split all of it up and transport it inland into all those countries.

Even if the first part is even feasible, that second part is another world of hurt. Oh, and the part before the first part, where we fill Africa with solar to provide the world with electricity for 12-ish hours a day. The geopolitics of this all are going to be pretty much impossible to figure out and that's before any actual engineering can even begin to be done.

Undersea power cables are already very much a thing, and energy transport across the grid is also very much a thing; Europe already has it (https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta...). You're describing normal, already implemented stuff with a sense of incredulity I'm not sure I understand.

At completely different scales than providing an entire country's energy needs through two cables. The UK currently has more than 2000 power stations providing balanced electricity throughout the country. The international transport is also for balancing, not for providing an entire country's energy needs from another country.

You can't just connect 20 cable's from Africa to the European grid and expect it to work, that's not how the grid works. And I'm truly surprised that many people on HN seem to think it would.

Source: I work in utilities and one of my current focus area's is creating software to help expand the net to cope with the addition of new renewable sources and EV charging stations. And even that is posing a massive challenge on a relatively small and local scale. I couldn't imagine the impact of this fantasy of just plugging in some cables from Africa somewhere.

Edit: This incident is an example of how sensitive all this stuff is:

https://www.bloomberg.com/news/articles/2021-01-27/green-shi...

Distributed power generation made sense when everyone used coal power plants - it was cheaper to ship trains full of coal than the power.

But if you want a carbon-free grid, then you can't ship the light or the wind. You either massively overbuild generation and throw most of the power away, build huge amounts of very expensive storage, or you ship the power.

Currently the world is headed towards overbuilding, but thats only because typically private companies build power generation, whereas power transport is mostly in the realm of governments, and governments are slower to act on market forces (and often aren't great at capital efficiency).

The end result will clearly be a mixture of all 3, but we're going to see a lot more power movement in the next 50 years than we saw in the last 50 years.

All of that is correct, but I don't see how it's relevant to my argument that plugging a couple of cables into Europe is not a feasible solution and would take massive amounts of work in geopolitics, let alone the engineering to adapt the grid to make it possible.

And would be a heck of a terrorist target anywhere along its length.

Good point, an important part of the resilience of the grid is the fact that there are hardly any significant points of failure.

That's interesting. Not knowing much about electricity read somewhere that it goes ~500km max and was wondering how are they going to get it from Africa to Europe.

It ran into financial troubles, but https://en.wikipedia.org/wiki/Australia-Asia_Power_Link was to be 2,800 miles long.

The Morocco-UK cable mentioned in the article would be 2,400; "transmission losses for such a long cable will be relatively high at 13%". https://en.wikipedia.org/wiki/Xlinks_Morocco-UK_Power_Projec...

Hmm- finacial in the sense that at least one large investor went "Nope".

The underlying actual issue was the cable path .. not so much the length but the trip across a lively and still active earthquake | volcano | fault ridden region ( that spawned the Krakatoa eruption and others ).

The engineering, repeater stations, need for a "backup" cable (that was just as likely to break) etc just didn't add up.

The Singapore | Australia cable project may rise again - but for now exporting Australian sunlight is going forward via ammonia shipments.

Yes; the point is that mere cable length doesn't seem to be an inherently unsolvable physics problem.

The 500km max number was before people considered using voltages over ~400kV. Those higher voltages are now more feasible due to solid state power conversion and better insulators.

Also, 500km was a good economic number, because typically if you need to move power more than 500km, then it is better to build generation at the other end and ship the coal/oil there.

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