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Comment by svalorzen | Hacker News Reader

There's something I never understood though. Technically there's always a side of the Earth that is under the Sun, so why can't countries make some sort of equal-sharing energy agreement to avoid needing batteries, if not at all at least hugely decreas the need for them? So that when it's night on one side of the Earth, everything just runs off the surplus on the other side?

Is it just too hard to move electricity so far away?

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Yes, it's very difficult to move electricity far distances. I believe it has to do with the natural resistance of copper. While its quite low, it's not zero and it adds up over hundreds of miles of copper. IANAE so anyone feel free to correct me on that

It doesn't seem feasible without low cost superconducting power lines.

For context, the average transmission loss between generator and consumption in the US is ~11%. This is generally over relatively short distances when compared to actual transmission.

In the short term, transmission lines are congested during peak hours so we often can't pipe enough power to high demand markets.

Look up High Voltage DC. Answer - It is hard - but not insurmountable. Technology and financing is readily available. It's lack of will, vision and integrating policies across national boundaries that's the problem.

“Let’s Build a Global Power Grid - IEEE Spectrum”

http://spectrum.ieee.org/energy/the-smarter-grid/lets-build-...

So you are saying run a power line across the ocean, so the US can power Europe and Vice Versa?

Maintaining fiber optic cables can be hard across the ocean. How about a power line that has a diameter of 50 feet? I can't even imagine the engineering of that.

Info on losses here: https://en.wikipedia.org/wiki/Electric_power_transmission#Lo...

No idea on the math for what % of power we would lose across the ocean.

Seems local batteries would win out..

The article says that a 100-mile 765kV transmission line loses 1.5% to 0.5%. Let's be optimistic and assume we can get closer to the latter and deliver 99.5% of original power over 100 miles. NYC-LON is 3,466 miles on the shortest possible path. Let's call it 3,500 miles. Over that distance, we'd deliver 99.5% ^ (3,500 / 100) = 83% of our original power.

The circumference of the earth at the equator is 24,901 miles. Halfway around the world, we'd deliver 29% of original power.

at that scale, thousands of miles, and enough power to drive a continent, maybe superconducting cables are worth it.

Local kinetic storage like pumped hydro have an efficiency advantage over batteries (at least with current tech)

I think you are forgetting that the earth is big. Running power lines big enough to power half of the planet thousands of miles across the ocean will be very difficult.

Transmission losses over large distances are high. And long distance transmission infrastructure is expensive. High Voltage DC (HVDC) is very expensive.

The holy grail in transmission is high temperature super conductors. We're not there yet.

If you think HVDC is expensive, I'm not sure why you think HTSC's would be better.

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