> Even if its cheaper to build small reactor vessels, MANY of the other costs become more expensive in larger numbers.
There is no way SMR could beat solar+battery power cost even now. With sodium and other batteries projected to reduce storage cost, it is even more unlikely that SMR could be price competitive in future grids. SMR is the only way that dying western nuclear industry could attempt to deal with ballooning compliance and finance costs and hope for revival. China or India doesn't have this compliance cost and still build conventional nuclear.
Even for the SMR usecase that got funding recently, mega datacenter electricity, there is new geothermal power companies getting funding and are transitioning from pilot projects to production. Some are using tech that is already being used in oil fracking industry for decades, so new geothermal tech scaling up has far less roadblocks technology and compliance wise. So other than military and mobile civil applications like nuclear icebreaker, I don't see the chance of SMR succeeding anywhere else.
To a first approximation, China does not build nuclear power. Nuclear's share of power production in China is 4% and dropping. It seems to me that the main reason China keeps building a relatively tiny amount of nuclear is strategic. Reasons like ensuring they never forget how and ensuring they always have buildable designs so that if something changed they could ramp up the program. And probably even more likely: nuclear expertise is important to the country's military.
But coal is still 49%. The whole point of nuclear in a carbon-free, mostly-renewable grid is to avoid needing enormous amounts of storage and overproduction. That's a need that doesn't come up when you're still half fossil.
If you want to decarbonize as fast as possible, it makes sense to focus on rolling out wind/solar/battery as fast as possible for now, but keep developing nuclear technology to cover the last bit where it starts getting especially expensive to replace fossil with renewables without losing reliable power. That's exactly what China appears to be doing. They're not just building a few reactors, they're also the world leaders in developing various GenIV designs, like molten salt reactors.
The most cost efficient new-build grid is 90-98% solar/wind/battery depending on your locales insolation & wind coverage. (Source Ember Energy) The remaining 2-10% is nat gas, if you have a piped source, or coal if you don't.
But 98% renewable doesn't mean you can hit 100% by adding 2% more of something else, it means your something else has to supply ~100% of the power 2% of the time.
If China is aiming for that cost-optimal 90-98% renewables, that means they need to build a lot of coal.
It would also be better if you ate only vegetables and drove an ultralight (ebike) good luck. I personally like being able to turn on my lights 100% of the time
It's not about lights, it's about electricity always being available.
And well, always having power available (for domestic, but also for expensive production facilities that looses money while idle) using renewables is a lot more expensive than generating most of your power with renewables
Solar battery is not by any stretch of any possible definition the cheapest generation to deploy. Not even close. We do a disservice to the entire conversation saying easily falsifiable things like that. At 90% penetration solar + battery has a LFSCOE somewhere around $800/mwh depending on the study. Natural gas is something like 30-60. Solar panels are cheap. Building the required transmission and storage to service those panels is far more expensive than the panels themselves.
Increased renewable generation is an important goal, but we need to let the facts guide the path, not the other way around.
A) I am an electrical engineer who makes a living designing control systems for renewable generation. I know more about most of this than just about anyone in this conversation.
B) the post I am replying to is specifically calling for a 98% solar grid.
You replied to: "The most cost efficient new-build grid is 90-98% solar/wind/battery depending on your locales insolation & wind coverage. (Source Ember Energy)"
There's a big difference between "letting the facts guide the path" and tilting at strawmen built out of straw nobody else even brought into the discussion.
If you'd like to make the point that "cost of panels" can be misleading when supporting components and interconnects begin to take up the lion's share of costs then that sounds like a noble thing to remind folk of, but ideally not as a segway into shilling more fracking which includes untold environmental costs as externalities.
That's a fundamental problem with nuclear plants. Their classic "baseload" niche is gone. Like the intermittent sources, wind and solar, they need storage to hold what they overproduce during peak periods.
This is also true of geothermal, which, like nuclear, is almost all fixed capital cost.
It's only a problem because of capitalism. Every plant needs to independently make money, so nobody wants to be the ones spinning down because that's their profit margin dwindling.
But society would be better off with excess generation. So we either need a system where some are incentivized to spin down, perhaps by being paid a consistent amount regardless or something like that, or we need publicly owned power generation that doesn't care about profit.
This argument assumes we must build nuclear power.
The problem is that electricity is fundamentally priced on the margin. Now that we are moving beyond a purely centralized design.
Think about a homeowner or factory with their own renewables and storage.
They fundamentally operate on marginal price by choosing when they use their own system and when they buy from the grid.
If you add state owned reliable power to this mix they will cherry-pick. Their own cheap electricity when it delivers and the states subsidized reliable electricity when it doesn’t.
We can try add all manner of markets, fixed connection costs and what not to this but all it does is introduce strange arbitrage possibilities in the market.
Which is why we have settled on net energy markets and then the lowest possible amount of ancillary markets to shore up any gaps which would cause problems for the larger society.
We have needed to build nuclear power since the day it was invented. The amount of fossil fueled power generation is indisputable proof of that.
The only way we don't need nuclear power is if we have some other way of producing the energy we need without dooming the planet, and obviously we do not as we're still burning billions of tons of coal every year. Not to mention gas.
We could have made power generation fully fossil free many decades ago if we actually took climate change seriously. It would have been fine. Sure fossil fuels may have been cheaper, but if you include the damage they're already causing and will cause in the future you could multiply the cost of nuclear by orders of magnitude and it would still come out on top. Plus higher investment would lead to faster improvement in the technology, mass production of components and lower cost etc.
I agree that renewable with storage is cheaper of you price in destruction of habitable zones of the planet. Most people don't, and the dollar cost of the storage is a problem over fossil.
The coal argument about China doesn't hold water when you look at what they're actually building. Around 80% of their new power sources are renewable, and 10 to 15% is coal. They're aggressively focusing primarily on building renewable -- so to say that their coal is 49% is either misleading or entirely missing the point.
This assumes that the renewables built are actually contributing to the economy, which we don‘t actually know for sure. In fact there was an article stating that they discard a lot of the energy produced because the grid cannot deliver. [1]
> China, the world's top producer of solar power, rejected 360 terawatt-hours (TWh) of clean power from January to June, up 49% from the same period a year earlier, according to a report this month by Global Energy Monitor (GEM) and the Center for Research on Energy and Clean Air (CREA).
which is great, but as i understand it will still lead to an overall decline in share of nuclear power. The scale of their power production is unfathomable
No, almost every one is above 1GW - divide the net capacity by the number under construction to see the power [1]. They appear to be almost all CAP1400 (1.4GW), Hualong One (1.0GW), or CAP1000 (1.0GW). I see a single Linglong 1 (100MW) under construction. Proposed are all above 1GW.
You need to look at where those nuclear plants are being built, in the east, and where the new energy is out west that makes it appear that nuclear is falling behind. Having power generation that doesn’t need to be transported via UHV lines is useful, it also acts as a nice baseline that keeps the grid stable.
China is building more new nuclear power than the rest of the world combined. They’ll soon produce as much renewable electricity as the United States produces electricity
> There is no way SMR could beat solar+battery power cost even now.
Not a particular fan of this paper, but it does illustrate a point ... https://ieeexplore.ieee.org/document/8867359 showed that for the UK to go 100% solar it would need an energy capacity of 1/3 of the total grid energy demand over the year. Figure 6 A shows the big trend of 6 1/2 months of discharge and 5 1/2 months of charge (i.e. cycle perhaps once a year). Seasonal variations do matter.
It also seems like they are constraining the system to have no overproduction.
It’s like assuming that a fossil based system has all its producers generating the expected capacity factor and then smoothing out the season and daily demand changes with storage. Due to the difference between summer and winter demand such a fossil system would also need to have months of storage to compensate.
Which of course is absolute stupidity. When you can just overbuild production capacity and leave a far simpler problem to solve.
The underlying demand and production has not changed so much since then. The requirements for storage still exist, and strongly depend on when the power is delivered as well as needed.
> a fossil system would also need to have months of storage
Coal and gas also get produced in the winter at a relatively constant rate. Plus we know how to handle piles of coal, caverns full of gas, tanks full of LNG, and linepack for shorter duration gas storage.
> you can just overbuild production capacity and leave a far simpler problem to solve
Sure, you then have an economic problem. The effective capacity factor of the intermittents get driven down. How are they going to be paid for, if much of the time the market is saturated?
I find it telling that you call it an ”economic problem” and ”intermittents”. It seems like you have an axe to grind, but not much backing your standpoint anymore. So you’ve fallen to using derogatory.
Those same fossil fuels have the same economic ”crowding” out problem when cheaper sources in the same class delivers.
A single cycle gas turbine would love to get paid running at 100% all year around. It doesn’t because CCGT plants with higher efficiency undercut it.
Just like what happens in renewables. They start crowding out each other. Storage steps in and solves the peaks. More renewables come online until they ”crowd each other out” and around we go.
That’s called being a market. Which you nuke fans seems deathly afraid of given the economics of new built nuclear power.
It is interesting to see how large-scale nuclear is handled.
120% and 60% increase in cost for FOAK and NOAK (Table 2-1), plus no learning rate for nuclear construction beyond that (Table C.2).
Interest rates during construction unfairly penalise nuclear as "GenCost uses the simplest way which is to increase the capital cost by the assumed discount rate raised to the power of the construction time" (page 97)." This results in ~20% increase in capital costs against other simple scenarios like equal construction costs across each year.
30 year plant lifetime, rather than say 60 years. That results in ~10% increase in capital costs.
> Those same fossil fuels have the same economic ”crowding” out problem when cheaper sources in the same class delivers.
That line of reasoning only works if there is something to make one plant more expensive to produce electricity than another. For natural gas the cost of fuel is far greater than the CAPEX. For intermittents only the variable OPEX can distinguish between generators, which is mostly for wind and I guess most severely for offshore wind. Cannibalisation is the big problem for intermittents. The notion of succession doesn't work for them.
Now you’re desperately trying to rationalize new built nuclear power.
GenCost has an amazing FAQ section you evidently either ignored, or did not peruse.
For example here they discuss economic life vs operational life, when you live in reality rather than grasping for straws:
> Why is the economic life used in LCOE calculations instead of the fulloperational life?
> The LCOE calculation converts all upfront and ongoing costs to annual costs which is then divided
by annual production. The capital cost component of a technology is converted to an annual
repayment to the debt and equity providers. The annual repayment amount is determined using
the economic life and the weighted average cost of capital. The economic life is shorter than the
asset life for some technologies such as coal, nuclear and hydro. Some stakeholders have queried
why this is so.
> Debt and equity providers require a shorter payback period than the total asset life for some
technologies to avoid the risk that part of the equipment might fail or might need new investment
(sometimes called refurbishment or extension costs) to keep operating safely and reliably. To
determine the economic life, debt and equity providers might look to the warranties provided
with the equipment. They might also look at the typical timing of refurbishments or life extensions
for that technology. The economic life is an input provided by the engineering firm that AEMO
commissions each year as an input to GenCost.
> Some stakeholders suggested that coal and nuclear could access special financing arrangements to
move the economic life closer to the asset life. However, our preference is not to introduce special
arrangements for technologies where there is limited Australian evidence. A common approach to
the LCOE calculation is important to maintain comparability. The 2024-25 report does explore the impact of longer capital recovery periods in Section 2. It finds there is no significant benefit from
the longer operational life of nuclear relative to shorter-lived technologies whose costs have been
falling over time.
Even looking at China and South Korea they see essentially zero learning effects across plants after the FOAK build. Small ones at the same plant.
Crying about FOAK vs NOAK is not even close to solving the absolutely stupidly large subsidies new built nuclear power needs.
Again with the loaded terms. Sad. The market is limited until for example Jevons paradox expands it. Which will never happen with new built nuclear power due to how expensive the electricity is, that leads to energy poverty for generations instead. But I digress.
Look at Texas or California. About all new renewable projects in those markets are coupled with storage.
What you call cannabilisation, and try to paint like the end of the world, is simply the market working. Now pure renewable projects aren’t enough, instead you need to sell the electricity when the consumers demand it.
In just a year or two storage has massively smoothed out the price swings in Texas.
But again, that would require curiosity rather than desperately trying to poke holes the study already answered.
2.2 * 1.25 * 1.1 = 3.025x LCOE for the first nuclear power station.
1.6 * 1.25 * 1.1 = 2.2x LCOE for the second plant.
1.0 * 1.25 * 1.1 = 1.375x LCOE for remaining plant.
Wind/solar is heavily dependent on the required storage (which depends on matching supply and demand), additional transmission and backup generation prices.
Finding the price tipping points is the point of the exercise. When you catch someone's fingers on the scales you realise what the game is.
>For example here they discuss economic life vs operational life, when you live in reality rather than grasping for straws:
It's essentially just saying the market can't think long term enough leading to drastic differences in your calculations. But hence it's typically governments pushing these projects forward.
>The market is limited until for example Jevons paradox expands it. Which will never happen with new built nuclear power due to how expensive the electricity is
But it did happen for nuclear power in the past.
Now you see essentially the opposite.
>Why are you so afraid of renewables and storage?
I'm not. I think it's a great set of technologies. But I think if one tries to get to 100% everywhere one's going to stub their toes on the scenarios where it's not all roses.
Why? Because the storage part is hard at scale in a lot of places and the intermitency more pronounced.
In Texas and Cali are incredibly sunny places in the south of the US.
Silicon valley where it's already an issue gets 3 times as much sunshine hours during winter as let's say berlin and those hours are far less usefull.
>Crying about FOAK vs NOAK is not even close to solving the absolutely stupidly large subsidies new built nuclear power needs.
Is this not intentionally sidestepping the ludicrous amount of subsidies that have been handed out to renewables in aggregate?
Berlin would need to overproduce insane amounts in summer to handle it's winters.
The flip side is that what you are saying is that nuclear power will be commercially viable into the 2100s. And betting the house on that. While knowing that the electricity they provide is expensive enough to lead to energy poverty for generations.
That seems absolutely insane.
Jevons Paradox did not happen for nuclear power. What happened was crazy cost overruns, cancellations and the industry collapsing into its current state.
Who cares if we get to 95%, 97, 99% or 100% carbon neutral electricity when we still need to decarbonize agriculture, aviation, chemicals, industry, construction and so on?
Don't let perfect be the enemy of good enough. Transition that final firming to whatever carbon neutral sources we land on when their emissions matter in the late 2030s and 2040s.
We need to optimize decarbonization per dollar spent with the shortest time to market.
You do realize that renewable subsidies are being phased out all over the world? They aren't needed anymore. Complaining about "equality" because your desired solution didn't deliver in time is a kindergarten level argument.
We've spent the past 70 years subsidizing nuclear power. It just never delivered on its promise.
The relevant question is: Where does Germany spend the next €100 billion today to avoid the most emissions?
And that is certainly not new built nuclear power.
>While knowing that the electricity they provide is expensive enough to lead to energy poverty for generations.
What are you on about?
>Jevons Paradox did not happen for nuclear power. What happened was crazy cost overruns, cancellations and the industry collapsing into its current state.
And the opposite happened in the past whilst europe was building bunch more of them.
>Who cares if we get 95%, 97, 99% or 100% when we still need to decarbonize agriculture, aviation, chemicals, industry, construction and so on?
Funny you say that when some of those are significantly harder. Are you going to turn on steel plants only in summer? Do you think that might have some effect?
>You do realize that renewable subsidies are being phased out all over the world? They aren't needed anymore. Complaining about "equality" because your desired solution didn't deliver in time is a kindergarten level argument.
You should tell my government and the neighbouring governments.
>We've spent the past 70 years subsidizing nuclear power. It just never delivered on its promise.
It did exactly that?
>The relevant question is: Where does Germany spend the next €100 billion today to avoid the most emissions?
it has spent €700 billion to $1 trillion on the energywende (a metric which doesn't properly include a lot of private investment) and ends as one of the worst emitters in europe whilst deindustrialising due to high energy prices.
They jerk eachother off about how high their renewables share of the economy is every summer and then import and fire up the browncoal and gasplants again troughout the other seasons. When that solar panel is producing a 10th of it's average summer output (already below the capacity everyone loves to roll with for articles) in winter there's only one big winner possible.
People like to point out how france's electricity production is subsidised when they come out looking good even when the gov intentionally puts a stick in it's wheels by essentially forcing it to subsidise pricing to competition.
> You do realize that renewable subsidies are being phased out all over the world?
CfD is going strong in the UK; it seems about the only way of deploying it, given the revenue uncertainty associated with market saturation/cannibalisation.
Of course, other subsidies exist. Feed in tariffs. Transmission charges. Capacity and ancillary service payments to provide services that solar/wind do not.
This tells me you are not serious. The easiest nuclear reactors to restart, as per that same nuclear lobby group, were those in the north.
Northern Germany is already overproducing electricity, leading to curtailment of renewables.
What problem are you solving with even more overproduction in the north leading to re-dispatch?
> CfD is going strong in the UK; it seems about the only way of deploying it, given the revenue uncertainty associated with market saturation/cannibalisation.
I love you now are trying to smear off-shore wind costs on everything. Of course not lookign at solar, storage or on-shore wind.
Lets lookat those. In Germany, which still do CFD bids for solar, even though a ton get built on pure market value, the CFD bids today are below the market price for the capture-rate of their electricity.
The CFDs are also structured to not pay out when electricity is zero or negative. They trade money for a tiny bit of certainty. That is how far we've come.
> Of course, other subsidies exist. Feed in tariffs. Transmission charges. Capacity and ancillary service payments to provide services that solar/wind do not.
Who pays when half the French nuclear fleet is offline? Who pays when the majority of the eastern european nuclear fleet is offline? Who pays for the N+1 requirements coming from nuclear power being enormous single points of failures leading to large reserves being necessary?
People like you love to complain about these things, but you can never formulate a solution where nuclear power is required to pay for the problem large single points of failures cause in the grid.
> Northern Germany is already overproducing electricity, leading to curtailment of renewables.
Overproducing some of the time. And pulling electricity from Sweden and Norway at other times.
> I love you now are trying to smear off-shore wind costs on everything.
Why is Denmark running the CfD auction if everything is so rosy for onshore wind and solar (plus batteries)?
> the CFD bids today are below the market price for the capture-rate of their electricity.
OK, they are betting on the future value of the electricity they produce being lower than today.
> The CFDs are also structured to not pay out when electricity is zero
So existing generators with older CfDs have priority over new generators with CfDs? Interesting.
> Who pays when half the French nuclear fleet is offline?
Why were they offline?
> Who pays for the N+1 requirements coming from nuclear power being enormous single points of failures leading to large reserves being necessary?
So the 1.X GW of standby is bad, but the whole-system sized standby required for intermittents is fine? Also let's not confuse the capacity factor of nuclear (including scheduled maintenance) with the odds of nuclear being offline unexpectedly.
> you can never formulate a solution where nuclear power is required to pay for the problem large single points of failures cause in the grid.
Wait, is this where I am meant to talk about SMRs? Or nuclear peaker power stations?
Namely, It's very easy to 'design to load' where you don't need to worry about the next shipment of Coal, or an extended weather event causing excessive cloud cover and depleting your reserves.
Heck, even as far as compared to LPG, you don't have to worry as much about disruptions or possible cost shifts around LPG supply.
Yes, I'm possibly tongue-in-cheek handwaving specific types of 'weather events' here and potential impacts, i.e. Tsunamis... OTOH it's a lot easier in current gen designs to make something that would have minimal risk for something, say, in the middle of nowhere Texas.
To be specific, solar with 4hr storage is price competitive with grid right now. Storage becomes expensive after that at 8hrs even with projected sodium or lithium prices. For a datacenter usage they probably need couple of days storage at 50hrs like the planned google datacenter. Only alternate chemistry batteries that could be scaled up easily like flow, iron air, zinc etc. could be competitive for multi day storage, though most of these are still at experimental or pilot stages.
> Google’s new Minnesota data center comes with the world’s largest battery—and won’t raise electric bills
> The tech giant says it will fund enough new wind, solar, and long-duration storage to cover the project’s power demand and avoid shifting costs to ratepayers.
It works better on a geographically spread-out grid, and the data centers are running into the same limit that renewable plants are, which is that the grid is struggling to keep up (in large part, in many places, due to a history of underinvestment).
Data centers with good load balancing between regions do not need exactly the same power 24/365 so the latest solar-wind-storage is already cheaper in theory. But it would take few years before production of sodium and other batteries will scale up and the mean time a turbine powered by natural gas wins.
> there is new geothermal power companies getting funding and are transitioning from pilot projects to production.
If geothermal works economically (outside of volcanic zones where it already does) then it's game over for any other power source except existing dams though because it solves all problems at once.
That'd be a great thing for humanity but I don't think it's worth stopping pursuing alternatives already, because it's still a big "if".
I'm not a geologist, but for comparison, the Siberian Traps[1] erupted for 2 million years, and there have been other large events on that scale. Any heat we release will be insignificant in comparison.
Technically it would, but the same way an individual ant's breath contribute to global warming.
Note that the thermal energy contained in the inner earth isn't a fixed amount: the earth constantly generates new heat from friction and radioactivity, and that new heat is radiated away in space at night, alone the heat captured from the sun during the day. So technically geothermal will increase the efficiency of this heat transfer a tiny bit, but it's really a negligible amount. (In reality the ant's contribution to global warming is probably orders of magnitude than the phenomenon we're talking about here).
Nope. It is very far away from core. Core is very big. And energy is already flowing outwards. So just using it really have not any significant impact.
Real issue is that it is not actually usable everywhere. Again Earth is big and going deep in some places is very hard.
I said the same thing about waiting for 24hrs before being able to use adb to install apps. About 24hrs being not a big blocker and that it was good for security. It's all about boiling the frog slowly, 24hrs is the start and then they'll add more restrictions once users accept that. Ultimately goog would like to have the system as much locked down as apple or even more.
> How do you clean forests? The debris is part of the forest, not all areas of a forest are easily accessible or feasible to transport debis out of there.
Cleaning is huge financial burden and has questionable outcome. Only extreme solution I can think of is fireblocks if situation gets worse which could worsen climate change by clearing trees. Divide forest in to grids, building roads wide enough to fire from spreading. Fill roads up with gravel or concrete to stop fires from spreading. Climate activists would never allow such plan to be implemented.
> You answered it yourself: it's not possible to get rid of the excess CO2. Think about conservation of energy: we extracted energy by burning stuff and producing CO2.
You can use pyrolysis to reduce usage of energy. Instead of building ethanol using corn etc, some fast growing crop can be converted to biochar using pyrolysis. And stored indefinitely underground or somewhere. Of course this isn't profitable and probably will run in to climate activists roadblocks.
There are so many proposals for improving errors, even half implemented ones that are dropped. I even stopped checking pros and cons after a few. As ultimately everything got rejected and the message is that you have to live with verbose checking with llms now.
Play Attestation is a Google hosted database of build keys/hashes for known Android builds. Android-side of this attestation is an API which calculates and returns those hashes to the app.
There's nothing preventing the app from verifying the build itself against its own database. So they can allowlist GrapheneOS builds if they want - but of course that means that all other ROMs are still banned.
Regarding Indian private space sector, In addition to skyroot solid rocket, following are noteworthy
Agnikul is planning to launch semi-cryo kerosene rocket pretty soon. Their engine is 3d printed and use electric pump fed 25kN small engine. Planning to launch 4 clustered engines as first stage and already did suborbital test, with some parachute splash down reusability claims.
Astrobase is recent entrant. With decent funding and former ISRO scientists as core team, developing 800kN FFCS methalox engine. FFCS is called holy grail of liquid engines. They have acquired largest metal 3d engine and planning VTVL 1st stage reusability
Also, Pixxel, Skyroot, and Agnikul are targeting orbital data center launches this year for defense applications (which is what the entire ODC story is about). The US NRO already uses India's Pixxel [0] along with Finland's ICEYE (which is now co-manufacturing synthetic aperture sats in India with Agnikul [1]) for hyperspectral scanning.
Edit: can't reply
> But.. why?
Missile Defense and C4ISR [2]. Seconds matter, so most of the newer generation of missile defense systems are experimenting with how to offload compute at the edge to reduce C2 latency.
Most orbital sat startups in the US, China, and India are partially backed by military and intel oriented funds (eg. Starcloud and IQT/In-Q-Tel).
This borders on science fiction. 88,000-and 1-million satellite clusters (as claimed in your link) are hard to take seriously, especially with the possibility of Kessler Syndrome. Also:
1. How do you cool your chips? Vacuum is a thermal insulator, so radiators are required to remove heat. nVidia (or even ASICs) require much and specialised cooling.
2. How does one radiation harden a H100?
3. I'm also seeing where TCO for these are 78x their terrestrial equivalents [0]. Is that financial sustainable?
And there still remain issues with power supply, regulations, and bandwidth. This feels more like a thought experiment rather than an actual serious engineering or business case.
The projections are questionable, but this is something the US and China are experimenting with as well.
1 and 2 are still open questions, but these are not aimed to be commercial grade DCs - this is basically edge compute (think a handful of racks). 3 is not a problem for defense usecases. (EDIT: Discussion here seems to point out that data OP is using might be flawed [1]).
Ignoring the fact that just about every orbital data center startup in the US is funded by IQT and China's CMF has been doing something similar is bad from a defense perspective.
Based on dealflow, these aren't being targeted for consumer usecases in the short-term and whoever has been saying that is misleading.
> especially with the possibility of Kessler Syndrome...
India, Russia, China, and the US don't care about Kessler Syndrome - they have already launched and deployed ASATs. This also comes after India and China had a near collision in 2024 that was treated as an offensive action [0].
Cost is the critical constraint for defense programs. Yes, militaries spend a shit-ton of money, but that's usually in a penny wise and pound foolish way. A dollar spent on your project is a dollar that's not spent on the innumerable things generals think are critical to their future wars like boondoggles, missiles, planes, ships, missile defense systems, etc.
The exception is if you're one of those rare projects. A starlink type constellation or launch capabilities certainly could be, but it's hard to imagine generals getting excited about compute in space just for the sake of it.
This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser.
Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist.
Same as with Musk's California Vacuum Tunnel (which diverted attention from passenger rail). And his Neuralink. In the 1980s, it was nuclear pumped space-based lasers and Soviet particle beam weapons.
All of the above can be debunked with 2 years undergrad physics and a Casio calculator. Yet they were still taken seriously by high-level politicians and business, some of whom were deeply connected with the military-industrial complex.
People have shrugging of questions like 1 and 2, only for 3 to hit them very hard. But we will see if they can launch 600 of these satellites as they claim.
Carnot's theorem and refridgeration cycles rear their head. Your heat pump still needs power to pump heat uphill., negating any savings from a smaller radiator. And what happens when you shrink a radiator? It becomes a high temperature radiator, meaning the GPU must operate outside its operational tmperature of about 70 degrees C. So small radiator = big pump + extra solar panels and batteries + dead GPU
Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
Yes, that was your response. It was a terrible and obviously invalid response, as I explained.
You never explained why the GPU temperature had to increase. Could you explain that now? The GPU would be on the cold side of the heat pump, not the hot side.
> Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
We ignore that issue, because we were debunking a bad argument about "the laws of physics". The laws of physics say nothing about budgets or complexity.
I can’t imagine how inefficient a country would be if they tamped down all their magical thinking. FFCS, SMILE, and EUVL are all magical thinking if you ask me. Some of the craziest things humans have ever conceived of.
Full-flow staged combustion is a rather logical - and not even particularly useful, we're talking about small percentage points - extension of staged flow combustion, and staged combustion is a rather obvious change to open-cycle schema - and I'm hyperbolizing just a little bit here.
Yes, it brings effects, and it's a cool technology. But saying that at least idea - or results - are fundamentally changing rocket engines... I think that's a stretch.
There’s nothing logical about trying to make non-oxidizing metal that can handle thousands of degrees of temperature, hundreds of bars of pressure, and a nearly pure-oxygen environment? The US essentially made fun of the Soviets for even trying. If you think it’s logical, you don’t understand the tech at all. It’s a borderline miracle, let alone simply “logical”.
Literal rocket scientists spent decades and careers saying it was a waste of time, and random people with zero expertise try to downplay it. I’ll never understand being THIS cocky is a subject one has clearly never touched.
Soviets were world leaders in liquid fuel rocket engines. They used oxygen-rich preburners in e.g very successful line of engines starting with RD-170. It was possible decades ago. And no downplaying.
It doesn't have to be modern to be a miracle. The steam engine is one, too! I think this is still true of FFCS rockets, but maybe we're just wondering at different things in this world :)
> 1. How do you cool your chips? Vacuum is a thermal insulator, so radiators are required to remove heat.
This is space 101 and honestly, at this point, I consider bringing this up as disqualifying from giving criticism on the topic.
> nVidia (or even ASICs) require much and specialised cooling.
Whatever. They generate N kW of heat, you need to shed N kW of heat, and you need to fit that within your budget. End of worry.
Pro tip: if you can slice your problem so that individual satellite needs to shed less than M kW of heat, where M corresponds to how much heat some existing, deployed satellite platform handles, you can just do your initial design around that satellite platform, replacing the "business payload" with yours.
This is e.g. how the unfairly criticized recent "satellite swarm TPUs" paper from Google handled it. Everyone who brought up cooling revealed themselves as not having read the first page and not having thought about it seriously for more than 30 seconds.
> 2. How does one radiation harden a H100?
See that paper for some ideas and considerations, as this is part of what they focused on, after solving cooling by sizing the per-satellite payload power needs to Starlink.
Yeah, there's no solution for heat dissolution at this time.
You can run a few cpus in space, you are a few seconds closer to the data to figure out something basic, but you cant do that much calculation. If you do much cpu intensive stuff, you just get hot quickly and you can't dissipate the heat. I'm sure new ways to cool down will be developed, but there's not even any experimental techniques, right?
ISS collects ~250 kW solar power. All of that needs eventually to be dissipated - the energy removed by communication radiowaves is small. ISS routinely handles this thermal question for decades.
There is nothing magical with cooling in space. Just a different environment - a rather well studied already, we send satellites to space for some 70 years almost. Saying there is no solution is incorrect - we have options, we have numbers, we can point to concrete questions and answers.
(1) seems to be the big question to me. Surely it would be much cheaper to simply stick a data centre up in the mountains somewhere, low enough to be fairly easy to reach but high enough to be nice and chilly?
You need your chip to not completely fail. Latch-up can destroy things. A complete failure of a SERDES may dramatically reduce the utility of the whole system.
It is in fact possible to have the Kessler syndrome in LEO, the debris doesn't just immediately fall out of the sky so in practice you just need to put more satellites into a specific orbit to reach the critical density where one satellite breaking leads to a runaway chain reaction.
Can’t two solid object with equal kinetic energy collide in such a way that most of the energy goes into one of them, giving it a velocity that boosts its orbit while the other one has lower velocity and de-orbits?
Or one object explode into two fragments, equal and opposite relative velocity, again pushing the one half into a higher orbit and de-orbiting the other half?
(Honest question, math major, never took orbital mechanics or played KSP much).
> Can’t two solid object with equal kinetic energy collide in such a way that most of the energy goes into one of them, giving it a velocity that boosts its orbit while the other one has lower velocity and de-orbits?
Sure, you can. Imagine shooting a bullet into a tungsten cube. The cube will go into a higher orbit, and the bullet will bounce back (and maybe de-orbit).
But the kicker here is that for this to work, the bullet has to be in a _higher_ orbit than the cube initially. So the end result is still fewer objects in higher orbits.
Another option is momentum transfer via elastic deformation - you shoot a bullet into a 45-degree facet of that tungsten cube, and the bullet then ricochets into a higher orbit. It ultimately works by momentarily storing the energy of the projectile as a plastic deformation of the facet. So it can't accelerate more than a few small fragments.
Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute?
- ed, disclosure: You seem to have edited your response whilst I was typing mine, adding in valuable links. Thanks!
> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute?
In the real world, "physics" is not necessarily the gating factor. There is a major concern about the environmental footprint of terrestrial data centers, to the point where major U.S. states are enacting moratoriums: https://www.governor.ny.gov/news/first-statewide-moratorium-.... These legal and social roadblocks must be accounted for in analyzing the viability of orbital data centers.
If the "physics" tells you that your satellite cannot radiate heat away from your nVidia GPU cluster because each H100 needs 1.1 meter square of radiator, then opinions do not matter. The same applies to power supply and bandwidth.
> Another way to think about it: An SSPP spacecraft with a 60-meter-by-60-meter surface area made using today’s space PV-cell technology would cost $36 million and weigh nearly 9,000 pounds, or almost as much as a Ford F-450 truck. With the ultra-lightweight PV-cell technology Atwater envisions, it would cost just $450,000 and weigh about 300 pounds, or about as much as an IKEA three-seat sofa
That’s megawatt-level solar power under 5 tons using today’s leading edge technology. Starship super heavy can launch 100 tons into LEO.
As to bandwidth, Starlink V3 backhaul capacity is 1 terabit. Microwave radio frequencies have an insane amount of bandwidth.
The Caltech Concept is just that — a concept. No prototype, no tests, no manufacturing, no results. When they achieve this order of magnitude improvement on a prototype scale, that's when we should take them seriously.
ISS today generates and radiates away about 120 KW of energy with its old tech 3250 sq m of panels panels and it's current radiators. That's what 3 H100 racks need
There may be an economic challenge - which seems to be the sort of problem mass manufacturing can solve very well.
There may be a compute model & latency problem, how do you organize model training when racks are much further apart than in traditional data centres (although speed of light is 50% faster in vacuum than glass fibre). But that's algorithms.
Relative to everything else in orbit, powering a rack of compute and some comms per satellite seems not really to be a physics problem.
The cost of replacement is exorbitant for commercial usecases, but is acceptable for defense usecases.
The issue is too many people are looking at the commercial usecase while ignoring the defense usecase that is what is actually driving the conversation and dealflow in this segment.
First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller. More power would be required (and the radiator would have to radiate this energy too) but the radiator could become much smaller.
The other problem is assuming the radiator is intercepting sunlight. But it can be shaded by reflective films or kept edge-on to the Sun.
> Ok, there are at least two bad assumptions there.
> First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller.
Carnot's theorem and refridgeration cycles rear their head. Your heat pump still needs power to pump heat uphill., negating any savings from a smaller radiator. And what happens when you shrink a radiator? It becomes a high temperature radiator, meaning the GPU must operate outside its operational tmperature of about 70 degrees C. So small radiator = big pump + extra solar panels and batteries + dead GPU
Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
>Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
Almost every satellite needs attitude control, so this isn't something out of the ordinary. I'm not sure solar tracking mechanisms really fall into the "expensive" or "complex" categories in 2026.
It's not just space, it's mass. A solar panel can be made very low in mass. The physical limit comes from the absorption of light in a thin layer of semiconductor. For CdTe, this would be about 1 micron. PV in space could be gossamer thin sheets of thin film semiconductors, with tremendous power/mass.
> Carnot's theorem and refridgeration cycles rear their head. Your heat pump still needs power to pump heat uphill., negating any savings from a smaller radiator. And what happens when you shrink a radiator? It becomes a high temperature radiator, meaning the GPU must operate outside its operational tmperature of about 70 degrees C.
Sorry, that's all nonsense. Yes, the extra power needs to be radiated. But the advantage of operating at high temperature is so extreme that the more effective radiation will overwhelm that unless the heat pump is extraordinarily inefficient. If the heat pump would be perfect, operating at the Carnot limit, then if it doubled the absolute radiator temperature it would double the amount of energy to be radiated, but the area of the radiator would decrease by a factor of (2^4)/(2) = 8.
As for the second point, no, this does not require the GPU to operate at higher temperature. What made you conclude it would?
> Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
I don't need to; I'm just debunking a bad argument. What you are doing there is called "moving the goalposts". But satellites normally have means of orienting PV toward the Sun. So, maybe have the radiator perpendicular to those? Those claiming the idea violates the laws of physics and using solar absoption on the radiator as part of the argument need to show no such scheme can work, even in principle.
Could you please stop breaking the site guidelines? Your account has been posting flamebait lately, and here you crossed into personal attack. Not cool. You can make your substantive points without any of that.
When someone else is wrong (or you feel they are), two options that work are to continue to respectfully provide correct information, or to stop replying. Getting into denunciation, spats, etc. is not a good option.
The numbers are easy to run, and the added power consumption is no joke. It’s even worse if your heat pump fails to achieve Carnot efficiency. Never mind that heat pumps can be heavy and may be completely destroyed by even a tiny micrometeoroid strike.
Yes, it needs more solar power. But solar panels should be much lighter than radiators, potentially vastly lighter. Even if Carnot efficiency is not approached there is plenty of room for improvement in the size of the radiators.
The other neat thing is that in space, the background temperatures are a lot lower than Earth due to lack of atmosphere, and available potentially more often than 1/2 the day cycle depending how high you're prepared to orbit.
If I understand correctly, NY is concerned about the power and water consumption.
1. How do they get power in space? (solar) Do the same on earth at 1/100 the cost (or build 50x the number of solar to account for atmospheric loss and you will still come out ahead)
2. How do they get water in space (they don't). Whatever they do in space to not need water, do the same on earth!
3. People don't like living near datacenters - put them in remote areas hundreds of miles away from people, after all space datacenters won't have employees . Again, at 1/100 or 1/1000 the cost.
The point is that while power and water is scarce in space, the NY state has no jurisdiction there. It might literally be easier to build data center in space than it is to overcome social and political pressure in NY.
It's extremely unlikely that companies will find no locations that let them build zero power zero water data centers. And bulk AI stuff isn't latency sensitive either so the acceptable build radius is huge.
Most locations that could provide guaranteed power for western companies with stable governments are also full of NIMBY or NGO who could easily blockade those datacenters. Then you'll have to run to offgrid locations where you have to build 24hr battery for solar with closed loop cooling. Is 24hr battery+solar on earth cheaper than LEO satellites in constant sun without batteries? That's the question that would make or break satellite datacenters, as political climate against AI datacenters is increasingly getting bad with increasing electricity prices.
Exactly. This whole thing is not about being able to build whatever they can afford, it’s about being in a (stupid) race to build it as fast as possible.
> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute?
Don't worry, most of the people online didn't get the memo on this.
One of the major selling points of orbital compute is power supply - more specifically, it turns out that, compared to beaming power from space, it's projected to be cheaper to move compute upwell instead - atmosphere losses for beamed power are just too big. Of course this doesn't matter if you can get cheap, clean power from elsewhere (e.g. nuclear).
This is in general data center case. Here, GP says the motivation is reducing C2 RTT, which makes sense for military applications.
The unit economic tradeoffs aren't quite that straightforward (beamed power is lossy enough to require more panels[1], but solar cells and satellite structures have longer useful lives than inference chips so over longer time periods you likely end up launching more stuff into space with disposable datacentres anyway[2], particularly given the datacentres also need bigger radiators. Other issues which favour power being beamed to the ground are not exposing those expensive chips to radiation, and being able to replace them on cycles dictated by inference chip innovation or end-of-life rather than fixed cycles depending on a satellite propellant budget...
The other comparison point is of course plain old terrestrial power sources, including energy storage in the mix if it relies heavily on solar power without a sufficiently global grid. Not having to launch into space buys a lot of power.
C2 RTT times and edge computation of large datasets collected in space make much more sense since unit economics aren't the driving factor, but are unlikely to need datacentres on the same scale as inference compute for the general population (another reason why this use case makes more sense)
[1]but I think the underrated problem with beamed power isn't just the low maturity of the technology, but that as soon as you start talking about sending power to earth via RF or laser you're going to encounter political opposition that makes objections to terrestrial datacentres seem tame....
[2]chips can in theory be replaced on orbit, but the "million satellite" filings are disposable. Replenishing propellant for a few large power stations, potentially on longer cycles, is a simpler task.
> but solar cells and satellite structures have longer useful lives than inference chips
The limiting factor on the lifetime of any satellite is fuel. Especially for large structures that are influenced a lot by atmospheric drag and solar wind.
Sure, but periodically refilling a propellant tank for a few large SBSP structure on-orbit involves less complexity than replacing racks of inference chips distributed across constellations of satellites as proposed by current filings. Which is why the latter structures are designed to be disposable and the former not.
SPSP proposals tend to operate in higher orbits than ODC proposals too, as they're less affected by latency and radiation, so their station-keeping requirements are less propellant-intensive.
Non-exclusive use of farmland or wasteland (or even - at least until maintenance complexity is considered - offshore) isn't a major barrier; we have many many miles of wires and pylons crossing farmland for regular terrestrial grids already. A rectenna looks more like a mesh than a set of panels: the idea is that the visible light spectrum passes through and the target microwave frequencies don't, so unlike a photovoltaic solar farm the land underneath is fine for farming. Nominally the land is safe to be occupied or passed through by humans too, although they might take some convincing. It becomes a problem when people start trying to get the rectennae banned...
Never. As the post you apparently quoted without reading said, we're talking about a rectenna composed of pylons and wires structured as a mesh that doesn't interrupt farming and can theoretically be offshore, not panels here
Space based solar power has much bigger challenges in gaining acceptance, proving the physics works in real world conditions and delivering on its promises than the theoretical possibility that there is absolutely no unoccupied region of land or sea
We could. The usual stumbling block is how to ship fissile material upwell without the risk of a launch failure spreading highly radioactive material over several countries.
> What's the power loss from beaming down power?
I think it's about 10% from atmosphere alone, but you have to add losses from other components in the system, including light -> current -> RF and RF -> current legs, and I've seen estimates ranging from 15% to 40% efficiency end to end; this random article includes breakdown with estimates, that multiplies down to 37.5% efficiency end-to-end.
Also to spell out another non-obvious aspect of beamed power, it turns out that it's not the efficiency that's the limiting factor per se, but land - you can improve efficiency by building larger rectennas, but it gets very expensive very quickly once you consider paying for land under them.
Everybody keeps talking about cheap, clean power. But where I live the price of power has gone up dramatically in recent years. Free power (well, marginally free, anyway) is a major plus.
In France, where we have relatively cheap and clean energy, they plan to build GW DCs with GWs setups of diesel backup generators. When these will run, the pollution will be staggering.
My concern is more in the realms of cooling. I know there's the potential for lots of 'free' energy up there, but how do you then ensure your space-based array of GPU farms bleed all of the resultant heat?
This is like "how do you ensure you can bring back home all the groceries you bought" kind of problem. Space 101. We know how much heat we can bleed off, how, and how fast, and this gives us bounds on how much power we can use, and that is the starting point - you design everything around that.
From a Defense perspective, it's acceptable if multiple ODC fails and you have to re-launch another one. This is why these are being treated as part of a mesh. These aren't supposed to be a commercial DC and are intended to be a mesh of multiple racks in orbit.
The fact that the US, China, Russia, and India have already deployed ASATs means a Kessler effect if a question of when and not if.
It's funny, people here said the same thing about Starlink. "Sure, it's technically possible, but you could only lose money by doing something like that. There's just no market for it."
At 1GW scale, I'd agree. But if you need around 40-50 racks to do image processing and alerting, that's largely a solved problem.
The whole thesis around ODCs is to basically mass deploy a bunch of replaceable racks en masse and consistently, such that any geospatial intel can be processed at the edge.
One fun fact that I coincidentally happen to know is Agnikul's office is actually very nice/fancy. They've got like an Aperture Science (or portal) theme going on, with white panelling and recessed sci fi style lights.
Oh, and everyone gets a white herman miller chair (or a very good clone).
India has developed ASAT, which is arguably more complicated that ICBM, agni series, they developed. India routinely understates ranges and appear non threatening. Agni5 and 6 are genuine ICBM, and with little tuning could reach anywhere in the world. India's bureaucracy and MEA is beset with gandhian mindset who try to avoid confrontations and minimise belligerence, opposite of PRC wolf warriors I guess.
> India's bureaucracy and MEA is beset with gandhian mindset who try to avoid confrontations and minimise belligerence, opposite of PRC wolf warriors I guess.
It isn't because of some purported Gandhian mindset. It's becuase India is in a pacing conflict with China and Pakistan, whereas China is in one with the US and historically the USSR. Assuming the Chagos Archipelago dispute gets resolved in the next decade (India and France backs it's return to Mauritius because Mauritius' police and military leadership are under direct Indian control [0] but the US prefers Chagos remaining under British control because we are closer aligned), India has no need to explicitly publicize ICBM capabilities that extend beyond China or Turkiye.
Additionally, publicly stating India has ICBM capabilities makes it harder to land transnational mining deals [1] because then discussions with Australia, Brazil, Canada, etc adopt a nuclear proliferation dimension as well as placing a target on India's private sector because of SpaceTech and DefenseTech's dual use implications.
I presume they're thinking any potential adversaries have functioning intelligence agencies, so something as public as a launch is sufficient. No need to come out and explicitly state it.
If I, some rando on the internet, can theorize "that sure looks like it could be turned into a storable icbm that could deliver a nuke to hawaii or Tierra del Fuego or anywhere else on the globe" can make that guess, then any other major world power is likely far ahead of me in analysis.
Also well known that having the institutional knowledge and technical capability to build or adapt something in a fairly short time frame is almost as good as having the thing ready to go.
> I presume they're thinking any potential adversaries have functioning intelligence agencies, so something as public as a launch is sufficient. No need to come out and explicitly state it.
> Also well known that having the institutional knowledge and technical capability to build or adapt something in a fairly short time frame is almost as good as having the thing ready to go.
This is similar to how Japan doesn't have nuclear weapons.
Not just about PoS device. During early credit/debit card days, lot of stores would pass on merchandise fees directly to customers, giving discount in case of cash transactions, some stores still charge extra. This is not allowed in west as credit cards require same price as cash transactions, and most users perceive credit card rewards as something positive as one would lose out on this rewards when using cash. In India perception is that one would be making loss* if using credit cards. UPI with no fees as of now, is perceived as equal to cash by most people not dealing with black money.
There is no way SMR could beat solar+battery power cost even now. With sodium and other batteries projected to reduce storage cost, it is even more unlikely that SMR could be price competitive in future grids. SMR is the only way that dying western nuclear industry could attempt to deal with ballooning compliance and finance costs and hope for revival. China or India doesn't have this compliance cost and still build conventional nuclear.
Even for the SMR usecase that got funding recently, mega datacenter electricity, there is new geothermal power companies getting funding and are transitioning from pilot projects to production. Some are using tech that is already being used in oil fracking industry for decades, so new geothermal tech scaling up has far less roadblocks technology and compliance wise. So other than military and mobile civil applications like nuclear icebreaker, I don't see the chance of SMR succeeding anywhere else.