4 ms·

> 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+bat

by mayama 1mo ago

> 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.

bryanlarsen 1mo ago
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.
- DennisP 1mo ago
  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.
  - ViewTrick1002 1mo ago
    The problem is that the economics of a ”firming”/”peaking” nuclear reactor is absolutely stupid due to essentially being only fixed costs. It is already stupidly expensive when running at 100% 24/7. Now try running it only when renewables and storage doesn’t deliver.
    - Animats 1mo ago
      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.
      - sfn42 1mo ago
        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.
        ViewTrick1002 1mo ago
        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.
- testing22321 1mo ago
  They have 36-38 reactors under construction today [1]. I think that’s a bit more than just keeping the wheels turning [1] https://www.eia.gov/todayinenergy/detail.php?id=67746 https://www.eia.gov/todayinenergy/detail.php?id=67746
  - dalyons 1mo ago
    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
    - testing22321 1mo ago
      Agree. They’re building a massive amount of nuclear. They’re building a monumental amount of solar+wind.
  - bryanlarsen 1mo ago
    Which works out to about 4 per year. And most of them are under 1GW.
    - testing22321 1mo ago
      And almost exactly half of all reactors under construction in the entire world.
    - SECProto 1mo ago
      > And most of them are under 1GW 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. [1] https://en.wikipedia.org/wiki/Nuclear_power_in_China#Future_projects https://en.wikipedia.org/wiki/Nuclear_power_in_China#Future_...
    - modo_mario 1mo ago
      That's far more than 4 per year? Their speed when building them has been pretty damn good.
- melling 1mo ago
  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
- seanmcdirmid 1mo ago
  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.
elcritch 1mo ago
If solar+battery were cheaper wouldn't the new AI data centers be opting to pay to build that rather than nuclear or LPG options?
- teamonkey 1mo ago
  They are cheaper, that’s why in most of the world, datacentres are being built where there’s copious solar or wind power. The problem is that they need full power 24/365.
  - fpoling 1mo ago
    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.
- Procrastes 1mo ago
  Some of the data centers in Texas are at least partly being built to turn surplus natural gas into cash.[1][2] 1. https://energynow.com/2026/03/us-natgas-prices-at-waha-hub-in-texas-remain-negative-for-record-25th-day/ https://energynow.com/2026/03/us-natgas-prices-at-waha-hub-i... 2. https://www.rbccm.com/en/insights/2026/05/natural-gas-powers-the-data-center-boom https://www.rbccm.com/en/insights/2026/05/natural-gas-powers...
- to11mtm 1mo ago
  Nuclear, FBOW, has one big advantage. 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.
- 1mo ago
stymaar 1mo ago
> 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".
- will5421 1mo ago
  Won’t geothermal cool the Earth’s core?
  - Procrastes 1mo ago
    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. 1. https://en.wikipedia.org/wiki/Siberian_Traps https://en.wikipedia.org/wiki/Siberian_Traps
  - marshray 1mo ago
    Not the core measurably, but my understanding is that it can very slowly cool the volume of earth immediately around the heat extraction site. I have full faith in modern engineers' ability to account for these effects in the plant designs.
  - MachineMan 1mo ago
    It could prevent volcanoes from erupting perhaps.
  - Ekaros 1mo ago
    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.
  - stymaar 1mo ago
chickenbig 1mo ago
> 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 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.
- ViewTrick1002 1mo ago
  Not sure what relevancy a 2019 paper has today? 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.
  - chickenbig 1mo ago
    > Not sure what relevancy a 2019 paper has today? 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?
    - ViewTrick1002 1mo ago
      We have vastly moved the scientific frontier of modeling our energy systems since 2019. All those analyses find that renewable grids are far cheaper than if involving new built nuclear power. Here are two modern papers on the subject: https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/GenCost_2025-26_Final_Report_20260715.pdf https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/Ge... https://www.sciencedirect.com/science/article/pii/S0360544226009837 https://www.sciencedirect.com/science/article/pii/S036054422... 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.

by mayama 1mo ago

bryanlarsen 1mo ago

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.

DennisP 1mo ago
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.
- ViewTrick1002 1mo ago
  The problem is that the economics of a ”firming”/”peaking” nuclear reactor is absolutely stupid due to essentially being only fixed costs. It is already stupidly expensive when running at 100% 24/7. Now try running it only when renewables and storage doesn’t deliver.
  - Animats 1mo ago
    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.
    - sfn42 1mo ago
      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.
      - ViewTrick1002 1mo ago
        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.
testing22321 1mo ago
They have 36-38 reactors under construction today [1]. I think that’s a bit more than just keeping the wheels turning [1] https://www.eia.gov/todayinenergy/detail.php?id=67746 https://www.eia.gov/todayinenergy/detail.php?id=67746
- dalyons 1mo ago
  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
  - testing22321 1mo ago
    Agree. They’re building a massive amount of nuclear. They’re building a monumental amount of solar+wind.
- bryanlarsen 1mo ago
  Which works out to about 4 per year. And most of them are under 1GW.
  - testing22321 1mo ago
    And almost exactly half of all reactors under construction in the entire world.
  - SECProto 1mo ago
    > And most of them are under 1GW 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. [1] https://en.wikipedia.org/wiki/Nuclear_power_in_China#Future_projects https://en.wikipedia.org/wiki/Nuclear_power_in_China#Future_...
  - modo_mario 1mo ago
    That's far more than 4 per year? Their speed when building them has been pretty damn good.
melling 1mo ago
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
seanmcdirmid 1mo ago
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.

elcritch 1mo ago

If solar+battery were cheaper wouldn't the new AI data centers be opting to pay to build that rather than nuclear or LPG options?

teamonkey 1mo ago
They are cheaper, that’s why in most of the world, datacentres are being built where there’s copious solar or wind power. The problem is that they need full power 24/365.
- fpoling 1mo ago
  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.
Procrastes 1mo ago
Some of the data centers in Texas are at least partly being built to turn surplus natural gas into cash.[1][2] 1. https://energynow.com/2026/03/us-natgas-prices-at-waha-hub-in-texas-remain-negative-for-record-25th-day/ https://energynow.com/2026/03/us-natgas-prices-at-waha-hub-i... 2. https://www.rbccm.com/en/insights/2026/05/natural-gas-powers-the-data-center-boom https://www.rbccm.com/en/insights/2026/05/natural-gas-powers...
to11mtm 1mo ago
Nuclear, FBOW, has one big advantage. 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.
1mo ago

stymaar 1mo ago

> 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".

will5421 1mo ago
Won’t geothermal cool the Earth’s core?
- Procrastes 1mo ago
  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. 1. https://en.wikipedia.org/wiki/Siberian_Traps https://en.wikipedia.org/wiki/Siberian_Traps
- marshray 1mo ago
  Not the core measurably, but my understanding is that it can very slowly cool the volume of earth immediately around the heat extraction site. I have full faith in modern engineers' ability to account for these effects in the plant designs.
- MachineMan 1mo ago
  It could prevent volcanoes from erupting perhaps.
- Ekaros 1mo ago
  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.
- stymaar 1mo ago

chickenbig 1mo ago

> 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 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.

ViewTrick1002 1mo ago
Not sure what relevancy a 2019 paper has today? 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.
- chickenbig 1mo ago
  > Not sure what relevancy a 2019 paper has today? 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?
  - ViewTrick1002 1mo ago
    We have vastly moved the scientific frontier of modeling our energy systems since 2019. All those analyses find that renewable grids are far cheaper than if involving new built nuclear power. Here are two modern papers on the subject: https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/GenCost_2025-26_Final_Report_20260715.pdf https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/Ge... https://www.sciencedirect.com/science/article/pii/S0360544226009837 https://www.sciencedirect.com/science/article/pii/S036054422... 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.