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Comment by hunglee2 | Hacker News Reader

Great post.

There is third option with excess solar energy production - send it elsewhere.

This is partly what China is doing with solar - concurrent with massive solar installation there is also extensive ultra-high-voltage electricity transmission lines being laid out, to load balance excess production in the sunny but sparsely populated N and W, with the excess consumption in the heavily populated S and E.

Australia, Morocco, Spain I think are also getting into this game, though in these cases for energy export

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In countries that span time zones (aka lines of longitude) the grid likely already provides for "lengthening" the solar day.

For example in the US solar power from the west coast could easily supplement east coast evening demand. Ditto east coast supplementing west coast mornings.

Yes, this means investment in Trans-continental grids, but that makes sense in countries that are hot and wide.

The word "easily" is doing a lot of heavy lifting there. Major expansions to the US grid won't be cheap, done quickly or easy to protect against terrorism. Getting agreement from all the stakeholders seems to sometimes be an issue - even the relatively small proposed Tres Amigas SuperStation has dragged on for many years and now looks like it won't happen.

agreed - any continental scale country (USA, Canada, Brazil, Russia, India, China, Australia - will have the a diversity of natural resources to become energy self sufficient. US especially for solar, but needs infrastructure build out - can't rely on private sector for energy

?? Sending it elsewhere is connecting it to the grid and basically arguing the opposite of the article.

We probably need superconductors for that.

Hydroelectric plants along the La Grande river in northern Quebec run a substantial part of New York and Boston. The power is transferred across about a thousand miles. Transmission loss is about 10%. Ten percent would be intolerable for fossil fuel generation but a quite acceptable cost in that context, given the generation is so cheap.

No, you don't need superconductors. HVDC works fine, and minimises transmission losses to an acceptable level for long distance transfer of power.

For reference:

  HVDC transmission losses are quoted at 3.5% per 1,000 km (620 mi), about 50% less than
  AC (6.7%) lines at the same voltage.

https://en.wikipedia.org/wiki/High-voltage_direct_current#Co...

No, just a very high voltage grid since P=I^2*R and with very high voltages I (current) decreases proportionately and therefore exponentially in resistive power loss.

there's the skin effect though https://en.wikipedia.org/wiki/Skin_effect

so high voltage DC is a better option

Need, no, but it would be awesome.

In fact with enough excess energy we could afford to generate enough liquid nitrogen at scale to have superconducting lines to improve efficiency.

The problem with the current crop of REBCO superconductors is not the cryogenics but the actual ceramic material being brittle. You can't make a wire or a cable, you can only operate with stiff, thin, fragile bars. On top of that. it's not cheap, $100-200 per meter of typical 200kA power band. I suppose copper is like an order of magnitude cheaper just for the cable, ignoring the whole liquid nitrogen piping.

The critical field in high temp superconductors is also much lower, which limits the current you can put through it.

Meh.

Probably not in China, since the math with respect to losses works out. The distance from, say, a sunny place like Lanzhou to Shanghai, or even to Guangzhou, is relatively close.

But of course, exporting from Australia to the rest of the world will be problematic. Not sure how that will work? My impression, however, was that they were only trying to get the energy to Singapore? Which should work. It is 3 times longer than what the Chinese are trying to do, and underwater. But again, theoretically, it should work.

Isn't Australia basically a giant pile of bauxite? They could use solar to make aluminum locally and transport that.

This is already in planning [1] for a few years, and recently progressed further [2].

[1]: https://imgur.com/YMMaM6E [2]: https://apnews.com/article/australia-singapore-solar-sun-cab...

Australia could make their land more productive with desalinization. Expensive energy is the main reason it isn’t done (what to do with the waste brine is the other bit).

Australia will export solar via undersea cables to close neighbours and via hydrogen to more distant locations

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