[credit_guy]

I find liquefied Hydrogen to make more sense. In case of conflict (like now), undersea cables can be sabotaged with plausible deniability. The Royal Navy can protect a tanker en route from Morocco to UK, or a convoy of such tankers, there were two times in the not so distant history when it had to do just that. But how do you protect a continuous line of a few thousand km?

Separately, if at some random point in the future the relations between the UK and Morocco go south, it’s much easier to change suppliers if you use tankers. The EU is investing massively in Hydrogen, so the Worldwide Hydrogen market will be quite mature in 10 to 20 years.

Even from Morocco’s point of view, the same calculus applies. If the UK sanctions Morocco, and refuses to take delivery of electricity, how do you find an alternate buyer if the transmission line is in place? With Hydrogen tankers, you simply start selling to China or someone else, or you put the Hydrogen in some medium-long term storage. This gives you more leeway to negotiate whatever diplomatic situation you found yourself in.

[kibwen]

Rather, the thing that makes the most sense is for countries to rely exclusively on local power generation, and completely eliminate their reliance on other countries for energy. There is no infrastructure more fundamental than energy, because energy underlies all other infrastructure. Swapping out oil or coal or gas for liquefied hydrogen (or enormous intercontinental power lines) just trades one poor situation for another. Don't rely on any energy that you couldn't immediately switch over to providing yourself, even if it means paying an eye-watering premium.

[kaibee]

> But how do you protect a continuous line of a few thousand km?

Cameras/sensors, and fast response time. You could put a sensor package every couple km. Given the amount of power this installation delivers, it wouldn't exactly break the bank.

[credit_guy]

The bottom of the ocean is a very dark place. Sun light does not penetrate beyond a dpeth of 200 meters. Your cameras need to have lights, and very powerful ones, but they won’t reach beyond, say 500 meters. So you will need many thousands of cameras and probably hundreds of autonomous submersible drones to be on station at all times. This does not come cheap. Leaving aside the fact that it may render the project uneconomical, after a few years of nothing happening, there will be lots of cost cutting pressures. Even without cost cutting, at depth things fail. You will have zones with no suveillance coverage. The problem with such a system is that 99% coverage is about as good as 0% coverage.