The quoted "1 TW of photovoltaic cells per year, globally" is the peak output, not the average output. They're only about 20% higher peak output in space… well, if you can keep them cool at least.
The 1TW is the rated peak power output. It's essentially the same in space. The thing that changes is the average fraction of this sustained over time (due to day/night/seasons/atmosphere, or the lack of all of the above).
It's still the same 1TW theoretical peak in space, it's just that you can actually use close to that full capacity all the time, whereas on earth you'd need to over-provision substantially and add storage, so 1TW of panels can only drive perhaps a few hundred GW of average load.
The dominant factor is "balance of system" aka soft costs, which are well over 50%.[0]
Orbit gets you the advantage of 1/5th the PV and no large daily smoothing battery, but also no on-site installation cost, no grid interconnect fees, no custom engineering drawings, no environmental permitting fees, no grid of concrete footers, no heavy steel frames to resist wind and snow loads. The "on-site installation" is just the panels unfolding, and during launch they're compact so the support structure can be relatively lightweight.
When you cost building the datacenter alone, it's cheaper on earth. When you cost building the solar + batteries + datacenter, it (can be) cheaper in space, if you build it right and have cheap orbital launch.
Yeah, soft costs like permitting and inspections are supposedly the main reason US residential solar costs $3/watt while Australian residential solar costs $1/watt. It was definitely the worst and least efficient part of our solar install, everything else was pretty straightforward. Also, running a pretty sizable array at our house, the seasonal variation is huge, and seasonal battery storage isn’t really a thing.
Besides making PV much more consistent, the main thing this seems to avoid is just the red tape around developing at huge scale, and basically being totally sovereign, which seems like it might be more important as tensions around this stuff ramp up. There’s clearly a backlash brewing against terrestrial data centers driving up utility bills, at least on the East Coast of the US.
The more I think about it, the more this seems like maybe not a terrible idea.
Realizing the impracticality of it (and that such approaches often collapse under the infeasibility of it) ... wouldn't it be better to... say... cover the Sahara in solar panels instead? That's gotta be cheaper than shipping them into space.
I think this is all ridiculous, to be clear, but re: this problem couldn't the radiators in theory be oriented so that they vent in opposite directions and cancel out any thrust that would be generated?
Satellites can adjust attitude so that the panels are always normal to the incident rays for maximum energy capture. And no weather/dust.
You also don't usually use the same exact kind of panels as terrestrial solar farms. Since you are going to space, you spend the extra money to get the highest possible efficiency in terms of W/kg. Terrestrial usually optimizes for W/$ nameplate capacity LCOE, which also includes installation and other costs.
For one or a few-off expensive satellites that are intended to last 10-20 years, then yes. But in this case the satellites will be more disposable and the game plan is to launch tons of them at the lowest cost per satellite and let the sheer numbers take care of reliability concerns.
It is similar to the biological tradeoff of having a few offspring and investing heavily in their safety and growth vs having thousands off offspring and investing nothing in their safety and growth.
Solar modules you can buy for your house usually have quoted power ratings at "max STC" or Standard Testing Conditions, which are based on insolation on Earth's surface.
> And then there’s that pesky night time and those annoying seasons.
The two options there are cluttering up the dawn dusk polar orbit more or going to high earth orbit so that you stay out of the shadow of the earth... and geostationary orbits are also in rather high demand.
I grew up on a rural farm in California with a dial-up connection that significantly hampered my ability to participate in the internet as a teenager. I got Starlink installed at my parents' house about five years ago, and it's resulted in me being able to spend considerably more time at home.
Even with their cheapest home plan, we're getting like 100 Mbps down and maybe 20 to 50 up. So it's just not true at all that you would have connections that are a megabit or two per second.
That's not what I'm suggesting. The post says "deep space". If you're going to try to harvest even a tiny percentage of the sun's energy, you're not doing that in Earth's orbit. The comparison is a webcam feed from Mars.
That's pretty much a solved problem. We've had geostationary constellations for TV broadcast at hundreds of megabytes for decades now, and lasers for sat-to-sat comms seems to be making decent progress as well.
> it is possible to put 500 to 1000 TW/year of AI satellites into deep space, meaningfully ascend the Kardashev scale and harness a non-trivial percentage of the Sun’s power
and, of course and inter-satellite comms and earth base station links to get the data up and down. Starlink is one thing at just above LEO a few hundred km and 20km apart, but spreading these around 10s of thousands of km and thosands of km apart is another thing
The intractable problem is heat dissipation. There is to little matter in space to absorb excess heat. You'd need thermal fins bigger than the solar cells. The satellite's mass would be dominated by the solar panels and heat fins such that maybe 1% of the mass would be usable compute. It would be 1000x easier to leave them on the moon and dissipate into the ground and 100000x easier to just keep making them on earth.
The quoted "1 TW of photovoltaic cells per year, globally" is the peak output, not the average output. They're only about 20% higher peak output in space… well, if you can keep them cool at least.
But there are no clouds in space and with the right orbit they are always facing the sun
You know how people sometimes dismiss PV by saying "what happens at night or in cloudy weather?"?
Well, what happens over the course of a year of night and clouds is that 1 TW-peak becomes an average of about 110 to 160 GW.
We're making ~1 TW-peak per year of PV right now.
The 1TW is the rated peak power output. It's essentially the same in space. The thing that changes is the average fraction of this sustained over time (due to day/night/seasons/atmosphere, or the lack of all of the above).
It's still the same 1TW theoretical peak in space, it's just that you can actually use close to that full capacity all the time, whereas on earth you'd need to over-provision substantially and add storage, so 1TW of panels can only drive perhaps a few hundred GW of average load.
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It is more than 5x less expensive to get surface area on earth’s surface.
The dominant factor is "balance of system" aka soft costs, which are well over 50%.[0]
Orbit gets you the advantage of 1/5th the PV and no large daily smoothing battery, but also no on-site installation cost, no grid interconnect fees, no custom engineering drawings, no environmental permitting fees, no grid of concrete footers, no heavy steel frames to resist wind and snow loads. The "on-site installation" is just the panels unfolding, and during launch they're compact so the support structure can be relatively lightweight.
When you cost building the datacenter alone, it's cheaper on earth. When you cost building the solar + batteries + datacenter, it (can be) cheaper in space, if you build it right and have cheap orbital launch.
[0] https://en.wikipedia.org/wiki/Balance_of_system
Funny, I would have included transportation as part of the installation cost. You didn't mention that one.
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Yeah, soft costs like permitting and inspections are supposedly the main reason US residential solar costs $3/watt while Australian residential solar costs $1/watt. It was definitely the worst and least efficient part of our solar install, everything else was pretty straightforward. Also, running a pretty sizable array at our house, the seasonal variation is huge, and seasonal battery storage isn’t really a thing.
Besides making PV much more consistent, the main thing this seems to avoid is just the red tape around developing at huge scale, and basically being totally sovereign, which seems like it might be more important as tensions around this stuff ramp up. There’s clearly a backlash brewing against terrestrial data centers driving up utility bills, at least on the East Coast of the US.
The more I think about it, the more this seems like maybe not a terrible idea.
No maintenance either
Right now it is.
However, the amount of available land is fixed and the demand for its use is growing. Solar isn't the only buyer in this real estate market.
We have so much excess land with no real use for it that our government actually pays farmers to grow corn on it to burn in cars.
Availability of land for solar production isn't remotely a real problem in the near term.
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Realizing the impracticality of it (and that such approaches often collapse under the infeasibility of it) ... wouldn't it be better to... say... cover the Sahara in solar panels instead? That's gotta be cheaper than shipping them into space.
https://inhabitat.com/worlds-largest-solar-project-sahara-de...
https://www.theguardian.com/business/2009/nov/01/solar-power...
(and a retrospective from 2023 - https://www.ecomena.org/desertec/ )
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the demand is pretty much fake and AI isn't actually making money, just gobbling investors money
Solar can always just go on the roof...
Fortunately there are no downsides to launching solar cells into space that would offset those gains.
Does that include all the required radiators to vent heat?
and of course, the continuous opposite boost needed to prevent the heat vent from knocking them out of orbit.
I think this is all ridiculous, to be clear, but re: this problem couldn't the radiators in theory be oriented so that they vent in opposite directions and cancel out any thrust that would be generated?
Now do waste heat.
Solar cells have exactly the same power rating on earth as in space surely? What would change is their capacity factor and so energy generation.
Satellites can adjust attitude so that the panels are always normal to the incident rays for maximum energy capture. And no weather/dust.
You also don't usually use the same exact kind of panels as terrestrial solar farms. Since you are going to space, you spend the extra money to get the highest possible efficiency in terms of W/kg. Terrestrial usually optimizes for W/$ nameplate capacity LCOE, which also includes installation and other costs.
For one or a few-off expensive satellites that are intended to last 10-20 years, then yes. But in this case the satellites will be more disposable and the game plan is to launch tons of them at the lowest cost per satellite and let the sheer numbers take care of reliability concerns.
It is similar to the biological tradeoff of having a few offspring and investing heavily in their safety and growth vs having thousands off offspring and investing nothing in their safety and growth.
The atmosphere is in the way, and they get pretty dirty on earth. Also it doesn't rain or get cloudy in space
Sure but like, just use even more solar panels? You can probably buy a lot of them for the cost of a satellite.
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And in geostationary, the planet hardly ever gets in the way. They get full sun 99.5% of the year.
even at 10% (say putting it on some northen pile of snow) it is still cheaper to put it on earth than launch it
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I'm all for efficiency, but I would think a hailstorm of space junk hits a lot harder than one of ice out on the farm.
Except it doesn't melt like regular hail so when further storms come up you could end being hit by the same hail more than once :\
Solar modules you can buy for your house usually have quoted power ratings at "max STC" or Standard Testing Conditions, which are based on insolation on Earth's surface.
https://wiki.pvmet.org/index.php?title=Standard_Test_Conditi...
So, a "400W panel" is rated to produce 400W at standard testing conditions.
I'm not sure how relevant that is to the numbers being thrown around in this thread, but thought I'd provide context.
Atmospheric derating brings insolation from about 1.367KW/m2 to about 1.0.
And then there’s that pesky night time and those annoying seasons.
It’s still not even remotely reasonable, but it’s definitely much higher in space.
> And then there’s that pesky night time and those annoying seasons.
The two options there are cluttering up the dawn dusk polar orbit more or going to high earth orbit so that you stay out of the shadow of the earth... and geostationary orbits are also in rather high demand.
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And how much of that power would be spent on high speed communications with Earth that aren't, you know, a megabit or two per second
I grew up on a rural farm in California with a dial-up connection that significantly hampered my ability to participate in the internet as a teenager. I got Starlink installed at my parents' house about five years ago, and it's resulted in me being able to spend considerably more time at home.
Even with their cheapest home plan, we're getting like 100 Mbps down and maybe 20 to 50 up. So it's just not true at all that you would have connections that are a megabit or two per second.
That's not what I'm suggesting. The post says "deep space". If you're going to try to harvest even a tiny percentage of the sun's energy, you're not doing that in Earth's orbit. The comparison is a webcam feed from Mars.
That's pretty much a solved problem. We've had geostationary constellations for TV broadcast at hundreds of megabytes for decades now, and lasers for sat-to-sat comms seems to be making decent progress as well.
> it is possible to put 500 to 1000 TW/year of AI satellites into deep space, meaningfully ascend the Kardashev scale and harness a non-trivial percentage of the Sun’s power
Which satellites are operating from "deep space"?
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and, of course and inter-satellite comms and earth base station links to get the data up and down. Starlink is one thing at just above LEO a few hundred km and 20km apart, but spreading these around 10s of thousands of km and thosands of km apart is another thing
The intractable problem is heat dissipation. There is to little matter in space to absorb excess heat. You'd need thermal fins bigger than the solar cells. The satellite's mass would be dominated by the solar panels and heat fins such that maybe 1% of the mass would be usable compute. It would be 1000x easier to leave them on the moon and dissipate into the ground and 100000x easier to just keep making them on earth.