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TalkativeVoyeur t1_ixq1g5n wrote

Reply to comment by RandomBitFry in European Space Agency to probe solar power from space. by Marciu73

Yeah, but solar panels and launches are getting cheap enough that it's not that much of an issue anymore. The big question now it's on the transmission and how well that works out. I really want to see this happening, it could be revolutionary

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Viper_63 t1_ixul7ib wrote

>that it's not that much of an issue anymore.

It actually still is a big issue though. And solar panels getting cheaper favors decentralised installation on the ground, if anything.

Unless you want to sent a literal death ray in to orbit you still need about as much space on the ground for the receiving array as you would with regular solar installations - only with all the added downsides of doing things "in space":

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

>A space-based solar power system might sound very cool and futuristic, and it may seem at first blush an obvious answer to intermittency, but this comes at a big cost. Among the possibly unanticipated challenges:

>* The gain over the a good location on the ground is only a factor of 3 (2.4× in summer, 4.2× in winter at 35° latitude).

  • It’s almost as hard to get energy back to the ground as it is to get the equipment into space in the first place.
  • The microwave link faces problems with transmission through the atmosphere, and also flirts with roasting ducks on the wing.
  • Diffraction of the downlink beam, together with energy density limits, means that very large areas of the ground still need to be dedicated to energy collection.

>Traditional solar photovoltaics in good locations can accomplish much the same for much reduced cost, and with only a few times more land than the microwave link approach would demand. The installations will be serviceable and will last longer. Batteries seem an easier way to cover storage shortcomings than launching stuff to space. I did not even address solar thermal schemes in this post, which competes well with photovoltaics and can very naturally build in storage capability.

>I am left puzzled as to why we would want to take a harder, more expensive road to solar power. I think it is just not intuitive to most how difficult and expensive space is. And perhaps they think it’s very futuristic and cool to push our power generation out to space: it fits the preferred narrative about where we’re going. I don’t know—I’m just guessing.

>Astronomers frequently face this issue: should we build a telescope/observatory on the ground, or launch something into space? The prevailing wisdom is that if the science can be accomplished on the ground, then by golly you’d best do it that way. You’ll have the result sooner, at less expense, and with a greater chance of success.

I am not certain this would even have realistic use cases for military applications, outside of actual space-based weapon systems (the afromentioned death ray).

The math simply doesn't add up, even if you assume unrealistic optimal conditions. Looking at the involved companies it's quite clear that these are bascially hand-outs to the industry.

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TalkativeVoyeur t1_ixuygy2 wrote

Yeah, im not sure it makes that much sense anymo. What I meant is that is a lot more technically feasible, even if impractical. I guess it's gonna be tested and then never used again. Btw, very good writeup!

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DynamicResonater t1_ixwiz6m wrote

  • A spaced based system could supply uninterrupted power with greater generation efficiency and could be built out much larger than its terrestrial counterpart.
  • Several plants in orbit could be networked for power sharing optimization while using the same transmission infrastructure.
  • Another facet is that a single power plant with orbital adjustments could be used across/between continents thus eliminating much terrestrial distribution infrastructure.

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Viper_63 t1_ixwvxre wrote

None of these address the inherent problems the technology has and which the aricle brings up, and it also directly contradicts the claim that you "could built them out much larger". You still need receiving arrays on the ground which have to be of comparable size to the solar parks you're aiming to replace.

Arguing generation efficiency is pointless, as the ratio is pretty much fixed and improving efficiency further will impact both space and terrestial arrays. The point is transmission and conversion efficiency, which is where the technology fails, because of the massive losses.

"Networking plants in orbit" will only exacerbate transmission losses and does not change the inherent limitations placed upon receiving arrays.

I don't even know what the last point is supposed to mean. Are you under the impression that we currently share power the same way we "share" internet connections? That Africa's powergrid is connected to the Americas'?

You can not feasibly eliminate any existing infrastructure with this. Ground based grids will always be more efficient than "beaming" anything. Geostationary orbit is 35000 km up.

Putting things "in space" doesn't magically solve problems, regardless of how cool it sounds. In this case it has more downsides and creates more problems than it actually "solves", not to mention making critical infrastructure exemely hard to maintain or replace. If anything it might make more sense to simply reflect sunlight. That way you at least don't end up with a completly useless groundstation if something on your space array breaks down.

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