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Comment by jibes21 | Hacker News Reader

Can someone explain how this makes sense economically, isn't it really expensive and lossy to transport electricity such a long distance?

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There is a price difference between the place you buy the electricity and the place you sell it. That pays for the debt that funded construction. As long as that price difference is high enough it makes financial sense.

You double the voltage and halve the resistance. With longer cables you can invest more in more expensive stuff at the ends to deal with the high voltage.

Resistance stays the same, loss due to resistance goes down. I’m not sure it halves either, it might be better than halving but I’m not sure myself.

Edit: Basic power loss formula is P=I^2R, so yes power loss is divided by 4 for a 2x increase in voltage assuming the target power delivered is held constant.

Usually the resistance does not stay the same, because it is preferred to use a thinner cable, to reduce its cost.

At a given power, double voltage means half current. If the resistance is kept the same, that means 4 times lower losses. If the resistance is doubled by using a thinner cable, that still results in two times lower losses.

Yeah I agree, I was just pointing out that a wire won’t change resistance due to voltage going up. Of course notwithstanding the wire heating up or something.

Thank you for the correction.

Sun shines for free once the initial infra is set up. Using HVDC at 1100 kV you could transfer up to 65% of the original power which doesn’t sound terrible.

yeah - dumb question from me as well. won't a lot of power be lost during transmission ?

What material would they use for the cables at those vast distances to make the numbers work ?

Obligatory jwz post on the topic: https://www.jwz.org/blog/2002/11/engineering-pornography/

22 years old and about three phase AC power on copper cables rather than HVDC power on aluminium cable.

But, sure, worth it for the HN=referrer porn JWZ throws up, I guess?

HVDC has reasonable losses over very long distances and solar is extremely cheap. I believe aluminum is used for these cables.

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