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Comment by raverbashing | Hacker News Reader

Because power losses will be absurd (unless you manage to find a room-temperature superconductor)

Pretty simple math, if you cable has 1 Ohm/km then the distance between the Northeastern most point in Canada to Ireland is around 3000 km (or 3x10E6m)

So suppose you have this very long extension cord, plug it on Canada (100V there to help the math) and plug a lamp on Ireland (an old incandescent 100W bulb, because it dims)

Your lamp is going to have 100 Ohms. Current is going to be 100V/(6100 ohms) = 16mA, making your lamp glow with 1.6W

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Let me quote Ramez Naam here:

Transmission costs money, but less than many believe. The cost of high voltage DC (HVDC) transmission lines is roughly 1 cents per kwh for 500 miles, or 1.5 cents per kwh for 1,000 miles transmitted. Over 1,000 miles, an HVDC line may lose 5% or so of the electricity it transmits.

I don't consider 5% per 1000 miles an "absurd" amount.

Yes, losses are lower with a higher voltage (which for HVDC are around 100kV/1MV - in orders of magnitude)

However doing it on terrain is much easier than doing it under the ocean

Why easier. You just drop it on the floor. You don't need land right s or towers to build.

Isolating 100kV is not trivial

That's why we need big towers

When you can't use towers (on land) you have all kinds of special isolation techniques

And couldn't we up the voltage even higher for vey long distances?

You don't need a room temperature superconductor. High temperature superconductors can be economically refrigerated today. The problem overland is encapsulation - under the sea this goes away since the environment is much more stable (and colder).

Fixing a 3000 km long refrigerator at depth of 4 km will be an interesting challenge.

Cables are generally raised to the surface to repair.

Anyway, it's only 50 miles from Russia to Alasca making this a relatively simple connection. Hawaii would be hard to justify unless it's really cheap.

However grid storage is generally fairly cheap. Just going east to west across Eurasia also gives very good solar coverage.

Yes, but adding refrigeration to a cable will make it firstly about thousand times more likely to need a repair, and when repairing, rather a lot less bendable and more fragile, thus making it also more difficult to repair.

There are also -- of course -- a lot of political problems with the idea of a a global electric grid. Like, what happens to your electrical system in case of an international crisis. Russia has used its gas supplies for political pressure in Europe, and other nations may do the same with electricity.

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