It's always better to generate electricity on the ground than attempt to beam it to the ground from space. The efficiency loss of beamed power is huge.
The efficiency loss of nighttime is approximately 100% if we’re talking about solar energy. At least at a most basic level, it’s not totally absurd to stick some kind of power beaming contraption in space where it is mostly not shadowed by the Earth and beam power to a ground station.
Any process for beaming power from *outside Earth's shadow* to a point on the ground within the shadow (i.e. local night), necessarily can also send power from somewhere else on the ground that is in sun, even though the planet is in the way (ground->space->ground).
I wouldn't be too surprised by beamed power being used on Mars, because that planet has global dust storms during which nowhere on the surface is getting much light, but it doesn't make as much sense here: because of the atmospheric window, you either use 0.4µm-to-10µm-wavelengths or 10cm-to-10m-wavelengths* with not much in between, µm means lasers and the mere possibility you may have included lasers powerful enough to be useful means everyone else will demand something similar to the IEA nuclear inspection program or will put similar lasers on the ground and shoot them upward to destroy those satellites, while cm-wavelengths means each ground station is a *contiguous* roughly 10km diameter oval.
Given the expensive part of large-scale PV has shifted from the PV itself to the support structures they're on, the ground station ends up about the same cost as a same-sized PV installation, and because that's just the ground station this remains true even if all the space-side components are zero cost. Normal ground-based PV also has the advantage that it doesn't need to be contiguous.
It is also possible to use a purely-ground-based method to transfer power from the other side of the world; a cable thick enough that the resistance is only 1 Ω the long way around is already within the industrial capacity of China, but the same geopolitical issues that would make people hostile to foreign beamed power satellites also makes such a cable a non-starter for non-technical reasons.
I concur it’s not necessarily totally absurd — but when you consider that such contraptions require large — very large! — receiving arrays to be built on the ground, it’s hard to avoid concluding that building gigantic photovoltaic arrays in, say Arizona (for the US) along with batteries for overnight buffering and transmission lines would still be massively more efficient.
Is that more or less absurd than making deals with our neighbours to share their electricity? Build some solar farms around the planet and then distribute it over wire.
I honestly don't know the answer. I know there's some efficiency loss running over long wires too but I don't know what's more realistic.
We have these things called batteries, you charge them during the day, and drain them at night.
A solar+battery setup is already cheaper than a new gas plant. Beaming power from space is absolutely asinine, quite frankly. The losses are absurd, the sun already does it 24/7, and we know how to make wires and batteries to shuffle the sun's power around however we need to. Why on earth would we involve satellites?
amluto|27 days ago
ben_w|25 days ago
I wouldn't be too surprised by beamed power being used on Mars, because that planet has global dust storms during which nowhere on the surface is getting much light, but it doesn't make as much sense here: because of the atmospheric window, you either use 0.4µm-to-10µm-wavelengths or 10cm-to-10m-wavelengths* with not much in between, µm means lasers and the mere possibility you may have included lasers powerful enough to be useful means everyone else will demand something similar to the IEA nuclear inspection program or will put similar lasers on the ground and shoot them upward to destroy those satellites, while cm-wavelengths means each ground station is a *contiguous* roughly 10km diameter oval.
Given the expensive part of large-scale PV has shifted from the PV itself to the support structures they're on, the ground station ends up about the same cost as a same-sized PV installation, and because that's just the ground station this remains true even if all the space-side components are zero cost. Normal ground-based PV also has the advantage that it doesn't need to be contiguous.
It is also possible to use a purely-ground-based method to transfer power from the other side of the world; a cable thick enough that the resistance is only 1 Ω the long way around is already within the industrial capacity of China, but the same geopolitical issues that would make people hostile to foreign beamed power satellites also makes such a cable a non-starter for non-technical reasons.
* https://en.wikipedia.org/wiki/File:Atmospheric_electromagnet...
aaronharnly|26 days ago
hdjrudni|27 days ago
I honestly don't know the answer. I know there's some efficiency loss running over long wires too but I don't know what's more realistic.
unknown|26 days ago
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queenkjuul|26 days ago
A solar+battery setup is already cheaper than a new gas plant. Beaming power from space is absolutely asinine, quite frankly. The losses are absurd, the sun already does it 24/7, and we know how to make wires and batteries to shuffle the sun's power around however we need to. Why on earth would we involve satellites?