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I wonder if it could ever make sense to have ultra-high voltage or superconductive power transmission lines wrapping around the planet so that we could take advantage of the fact that it's always daytime somewhere to forgo much grid-scale storage and instead just get electricity from wherever it's daylight. Aside from the geopolitical/national security issues, I wonder if such a thing is feasible or it's ultimately going to be more efficient to store energy than transmit it half-way around the world.

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Originally I always fantasized about such tech but the technology required to develop this super conductor then produce it in the volumes needed, just think of all the communication cables that have been laid just seems insurmountable.

I think the best bet is finding more storage alternatives that can be replicated on a large scale and don't require any rare earth elements and localized enough to not worry abut shifting political alliances

You don't need magic superconductors for this; just high-voltage DC. The geopolitical problem remains, though.

Electricity transmission would be a foundational part of an orbital ring around Earth. And around a dynamo like Uranus, it could be used to generate electricity too.

This (long) video about orbital rings brings such things to mind. https://www.youtube.com/watch?v=LMbI6sk-62E

Buckminster Fuller thought of that long ago. http://www.geni.org/globalenergy/library/newsletters/1995/bu...

Circumference of the earth 40,000km Power loss .5-1.1% for 160km

If we assume 200km has 1% power loss then 20,000km is around 63% power loss.

He said super conductor. So no losses. Jus the cooling costs but we could insulate it really well.

High voltage dc might be another option to minimize losses.

> High voltage dc

I thought that was proven over a hundred years ago to not be an efficient way to carry electricity over long distances.. did something change recently?

Low voltage DC was bad. It had to be low voltage because there were only motor-generator, expensive and inefficient transformers for DC. Today, all conversions can be done in solid-state electronics. DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation.

> DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation.

Ok, what's a situation involving long distance transmission where DC-AC or DC-DC is best?

Wikipedia has a nice list[1] of existing and upcoming projects where transmission engineers judged HVDC to be the best solution. [1] https://en.wikipedia.org/wiki/List_of_HVDC_projects

DC-AC and DC-DC are just conversions - conversions used to be the problem with DC for distribution. For HVDC in an AC net you need AC-DC (not much of a problem) and DC-AC (more difficult, solved with only minor losses today).

The advantages of DC transmission are flexibility (can have power flow either way between any unsynchronized AC nets) and lower transmission losses per distance. The details are all on Wikipedia.

According to Wikipedia HVDC lines are <3% per 1000km[1]. So that leads to ~46% loss for 20000km.

If they could get it down to 1% per 1000 km, then it's only ~18% (for some value of only).

[1]: https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad...

Why use wires when we could possibly concentrate and beam the light across the ponds?

Curious how this would work from a practical standpoint? Could planes fly through it? How high off the ground would the light be beamed? Could a boat pass through it's path?

I know absolutely nothing about this area so just generally curious!

You can power planes with lasers. You could power rockets too.

1) You can't beam round a curved surface and the atmosphere isn't refractive enough in the visible spectrum (only works for shortwave radio)

2) The death ray is an environmental and safety hazard

3) Atmospheric attenuation would probably be more than electrical attenuation at that distance

I know HN is not for humor, but i really got a laugh out of “the death ray is an environmental and safety hazard”, listed with such seriousness.

Thankyou - that was entirely deliberate, you can only get humour past the HN voting system if either it's totally deadpan or you explain the joke in the same comment.

Satellite with a mirror at the apex?

wouldn't the energy efficiency be low? effectively: light source -> PV panels, focus etc are bound to be difficult (long distance so parallel rays, any tiny deviation... well schlieren photography) and then there's diffuse scattering

there's a big caveat: the pacific ocean

Is it possible to make floating Solar panels?

Anything is possible. We could power the entire US if we put a large collection of panels in the desert. Surprised there aren't self cleaning panels yet (maybe there are) :).

Yes, but why? You've got all the maintenance headaches of wave power with none of the benefit.

It might be useful for above-ground water reservoirs. They sometimes float balls on their surface to reduce evaporation in hot environments (especially ones with a breeze). If you could do the same with large arrays of floating solar panels, you could reduce evaporation and get energy out of it at the same time.

Distance from Americas to Eurasia by sea is under 55 miles. https://en.wikipedia.org/wiki/Bering_Strait

The longest undersea power line is 580km by comparison, so that' not a huge issue.

A straight path from the Mojave to the Gobi desert is 9000 km directly through the Bering Strait.

Why not just beam it from space?

It's expensive to launch stuff, and it's difficult to get power down from orbit without frying birds or creating a weapon.

>without frying birds or creating a weapon.

The weapons part would probably be bonus for some..

With a large enough collector, you don't fry birds.

https://dothemath.ucsd.edu/2012/03/space-based-solar-power/

The recommended transmission strength would be 230 W/m² in the center of the beam. This is about a quarter the strength of full sunlight, and is thought to be a safe level through which aircraft and birds can fly.

At this level, our 3.6 km diameter collecting area would generate about 40 GWh of energy in a day, at an assumed reception/conversion efficiency of 70%. By comparison, a flat array of 15%-efficient PV panels occupying the same area in the Mojave Desert would generate about a fourth as much energy averaged over the year

Does the 30% lost efficiency bleed into the environment as heat energy? While it's not as damaging as greenhouse gases, we should try to avoid adding more heat to our environment if possible. Especially when considering planetary-scale space power production and transmission.

I remember reading about a way to radiate heat energy from AC units directly to space.

"The panels do this by emitting heat at infrared wavelengths between 8 and 13 micrometers. To these waves, the Earth’s atmosphere is transparent. What’s more, the panels reflect nearly all the sunlight falling on them." [1]

Perhaps the same general concept could be used to transmit energy from space to earth while lowering interaction with the atmosphere.

[1] https://spectrum.ieee.org/energywise/green-tech/solar/effici...

You can probably balance things out a bit.

I don't think that "30% efficiency/loss" is the best way to think about this. Instead, think of it as "extra amount of sunlight reaching Earth" (and subtract the extra amount of radiation, which would probably be a second-order effect). If you've a 100m mirror illuminating the night-side of the planet, you'll need a k \* 100m size mirror shading the day-side part... And you'll probably need to calibrate this depending on the region you illuminate/shade as different parts of the Earth reflect/absorb different amounts of sunlight ("efficiency loss" I guess).

All in all, a very interesting problem indeed! I can't wait until humanity can "afford" such large-scale geo-engineering.

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