9 ms·

It's not that easy, and the 2025 blackout good evidence of that. Renewables need a grid that's engineered for them and that require significative investments. W

by samuel 6mo ago

It's not that easy, and the 2025 blackout good evidence of that. Renewables need a grid that's engineered for them and that require significative investments. Without them, closing power plants (of any kind) is, IMO, nonsensical. Ironically, Spain has plenty of Uranium, but there is an environmental law that doesn't allow its mining. https://alpoma.medium.com/uranium-in-spain-8ef975763257 https://alpoma.medium.com/uranium-in-spain-8ef975763257 This country is crazy.

tfourb 6mo ago
But doesn't nuclear power present a complication when designing a power grid for renewable energy? It is basically very expensive caseload energy that needs permanent demand, when the entire proposition of a renewable-focused grid is that you manage a non-certain production with dynamic demand (via batteries and price-sensitive usage).
- modo_mario 6mo ago
  Nuclear production doesn't react in seconds but it doesn't need permanent demand as far as I know? What makes you think that?
  - Krssst 6mo ago
    For reference: nuclear power plants can do load following: https://en.wikipedia.org/wiki/Load-following_power_plant#Nuclear_power_plants https://en.wikipedia.org/wiki/Load-following_power_plant#Nuc... It's more cost efficient to keep them running all the time since most of the cost of nuclear is building the power plant, but power output can be adjusted if needed.
  - tfourb 6mo ago
    A nuclear reactor can load-follow (increase or decrease their output) by up to 5% of their rated capacity per minute in normal operation: https://snetp.eu/wp-content/uploads/2020/05/SNETP-Factsheet-7-Load-following-capabilities-of-nuclear-power-plants.pdf https://snetp.eu/wp-content/uploads/2020/05/SNETP-Factsheet-... For power plants, this is glacial. A power grid has to balanced perfectly on a sub-second level. Also, you can only do this down to about 50% of rated capacity. Below that you have to switch it off completely. If you combine this with renewable generation, it all falls apart. A cloud passing over a large PV installation will drop generation much faster than nuclear plants will ever be able to follow (by increasing generation). So if you want to have a substantial share of renewable generation (which, remember, is the cheap stuff), you can't have more than a token nuclear capacity, because you need to invest the money you might want to spend on nuclear on battery and hydro storage. The other aspect is the economics of nuclear itself. Nuclear power plants are the most capital intensive generation capacity you can build. Even when driving them at the maximum of their rated capacity, the have a levelized cost of electricity several times that of PV and Wind per kwh. Requiring routine load following for nuclear would basically guarantee that no one ever builds a nuclear reactor again. There are reasons to build new nuclear, but it's not cheap/reliable power generation. You build it to have access to a nuclear industrial base, as well as the research and professional community to run a military nuclear program. Or you actually succeed in creating a Small Modular Reactor, which might be suitable for niche applications (i.e. power isolated communities in extreme remote locations). Or you are simply fascinated by the technology and want to invest a ton of money on the off chance that it will produce some unforeseen technological breakthrough (though arguably you'd do better with investing in nuclear fusion from my limited understanding of the research).
    - robocat 6mo ago
      > If you combine this with renewable generation, it all falls apart Rubbish. Only true if the renewable generation is poorly integrated. Solar plus batteries can provide synthetic inertia if the incentives/regulations are correctly designed. Australia has been adding oodles of solar, and they have been doing it surprisingly well. Nuclear can load follow, within limitations: https://news.ycombinator.com/item?id=36254716 https://news.ycombinator.com/item?id=36254716
      - tfourb 6mo ago
        > Solar plus batteries can provide synthetic inertia if the incentives/regulations are correctly designed. Yes, but why build nuclear at all, if you are already building PV + batteries? Nuclear is much more expensive than that combination. And if you add nuclear capacity on a level that actually matters (i.e. 30%+ of peak load), you run into real integration problems. As I've written elsewhere, a toke nuclear program can make sense if you want to keep the industrial base, institutional knowledge and expertise around, i.e. to guarantee independent access to nuclear weapons. But it is ludicrous to make nuclear a cornerstone of your energy policy. Not even China is expanding its share of nuclear in total energy generation. They keep it around as a strategic asset, but a subsidized one. For countries like Denmark and Spain I'd be pulling my hair out if my government would start throwing money into the money pit that is nuclear power (and it is inevitably is government money, because no nuclear power plant has ever been built without government subsidies and/or price guarantees). > Nuclear can load follow, within limitations Yes, but it makes zero economic sense to do so. Nuclear is multiple times more expensive per kwh than PV + batteries, even if you run it at max capacity continuously. If you require nuclear to load follow on a regular basis, not a single reactor will ever be built again.
        robocat 6mo ago
        > Yes, but why build nuclear at all I wasn't suggesting that. Why did you assume that and then argue against something I didn't say?
    - modo_mario 6mo ago
kuerbel 6mo ago
No it's not. Nuclear plants are not compatible with climate change. Spain and it's rivers will be too warm to cool them down: https://www.euronews.com/2025/07/02/france-and-switzerland-shut-down-nuclear-power-plants-amid-scorching-heatwave https://www.euronews.com/2025/07/02/france-and-switzerland-s...
- Ekaros 6mo ago
  Well only to certain point. When the rivers will naturally be too hot. You can start making them even hotter and it does not matter anymore.
- surfaceofthesun 6mo ago
  That may require retrofitting the plants to use open loop cooling instead of closed loop. That would increase water consumption.
yayachiken 6mo ago
> It's not that easy, and the 2025 blackout good evidence of that. Renewables need a grid that's engineered for them and that require significative investments. The outage in spain had multiple complex causes. While the grid had a rather routine instability/oscillation on-going during time of the incident, the actual point-of-no-return was completely non-technical: Prices crossed into the negatives, which caused generation to drop by hundreds of megawatts and load to increase likewise within a minute (!) because the price acted as a non-technical synchronized drop-off signal for the grid. In grids where the price action is not forwarded directly to the generators and consumers there would be no incentive to suddenly drop off decentralized generation. So for example in Germany a black-out would not happen like this. You can download the full ENTSO-E report here: https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/#Publications_&_Documents https://www.entsoe.eu/publications/blackout/28-april-2025-ib... (See page 10 for a broad incident timeline) Unfortunately, to have an informed opinion, you pretty much have to read all these pages, because the situation is just so complex. Otherwise, you just fall for agenda pushing from all sides.
- phatfish 6mo ago
  Yup, its interesting that a community supposedly of "engineers" are happy to claim expert knowledge of domains in which they have no experience.
  - yayachiken 6mo ago
    That being said, I was apparently also under the impression of outdated or just plain wrong information. While the report I listed mentions the sudden loss of decentralized generation as starting point of the blackout, and also specifically mentions small-scale rooftop PV, it says that the cause for that sudden synchronized drop-off is actually unknown.
    - robocat 6mo ago
      You can't get an "informed opinion" by reading crap like that report. The Spanish systems have systematic design failures for stability and electricity market design. Working out the political failures that led to the design failures is much harder. Consultancies like https://www.nera.com/capabilities/power--utilities--and-renewables-.html https://www.nera.com/capabilities/power--utilities--and-rene... specialize in advising about electricity networks and market design. Only those working closely in that profession have any knowledge of the underlying causes. Most everyone else (including this comment) is different levels of ignorance and cluelessness. Edit E.g. Crap quote from the report "but no significant oscillations with amplitudes above 20 mHz". The rest of it is about that level from what I could tell.
ViewTrick1002 6mo ago
Please tell me how renewables cause a lack of reactive power. Which was the source of the Iberian blackout. All reasonable grids already force renewables to handle reactive power if they want to connect, like they do for all electricity generation. It is a trivial expense, but still an expense so no one does it unless forced.
- adrian_b 6mo ago
  In another thread that comments the report it was said that most inverters used in Spain for the renewable energy sources do not implement a control policy to generate an adequate reactive power to compensate the phase fluctuations of the grid, like a synchronous electromechanical generator would do. The inverters only disconnected from the grid when the frequency went outside the permitted range. Ensuring that the inverters produce compensating reactive power would have been easy to do, but it was not done simply because there were no regulations that requested this. Obviously, as a consequence of the report, this is likely to change.
  - ViewTrick1002 6mo ago
    Yeah, been trivial forever. In the US it became a requirement for new all utility scale non-synchronous generators a decade ago. And then a bunch of statewide rules for rooftop solar as well. https://www.ferc.gov/news-events/news/ferc-moves-implement-fast-act-provisions-critical-infrastructure-information https://www.ferc.gov/news-events/news/ferc-moves-implement-f...

by samuel 6mo ago

tfourb 6mo ago

But doesn't nuclear power present a complication when designing a power grid for renewable energy? It is basically very expensive caseload energy that needs permanent demand, when the entire proposition of a renewable-focused grid is that you manage a non-certain production with dynamic demand (via batteries and price-sensitive usage).

modo_mario 6mo ago
Nuclear production doesn't react in seconds but it doesn't need permanent demand as far as I know? What makes you think that?
- Krssst 6mo ago
  For reference: nuclear power plants can do load following: https://en.wikipedia.org/wiki/Load-following_power_plant#Nuclear_power_plants https://en.wikipedia.org/wiki/Load-following_power_plant#Nuc... It's more cost efficient to keep them running all the time since most of the cost of nuclear is building the power plant, but power output can be adjusted if needed.
- tfourb 6mo ago
  A nuclear reactor can load-follow (increase or decrease their output) by up to 5% of their rated capacity per minute in normal operation: https://snetp.eu/wp-content/uploads/2020/05/SNETP-Factsheet-7-Load-following-capabilities-of-nuclear-power-plants.pdf https://snetp.eu/wp-content/uploads/2020/05/SNETP-Factsheet-... For power plants, this is glacial. A power grid has to balanced perfectly on a sub-second level. Also, you can only do this down to about 50% of rated capacity. Below that you have to switch it off completely. If you combine this with renewable generation, it all falls apart. A cloud passing over a large PV installation will drop generation much faster than nuclear plants will ever be able to follow (by increasing generation). So if you want to have a substantial share of renewable generation (which, remember, is the cheap stuff), you can't have more than a token nuclear capacity, because you need to invest the money you might want to spend on nuclear on battery and hydro storage. The other aspect is the economics of nuclear itself. Nuclear power plants are the most capital intensive generation capacity you can build. Even when driving them at the maximum of their rated capacity, the have a levelized cost of electricity several times that of PV and Wind per kwh. Requiring routine load following for nuclear would basically guarantee that no one ever builds a nuclear reactor again. There are reasons to build new nuclear, but it's not cheap/reliable power generation. You build it to have access to a nuclear industrial base, as well as the research and professional community to run a military nuclear program. Or you actually succeed in creating a Small Modular Reactor, which might be suitable for niche applications (i.e. power isolated communities in extreme remote locations). Or you are simply fascinated by the technology and want to invest a ton of money on the off chance that it will produce some unforeseen technological breakthrough (though arguably you'd do better with investing in nuclear fusion from my limited understanding of the research).
  - robocat 6mo ago
    > If you combine this with renewable generation, it all falls apart Rubbish. Only true if the renewable generation is poorly integrated. Solar plus batteries can provide synthetic inertia if the incentives/regulations are correctly designed. Australia has been adding oodles of solar, and they have been doing it surprisingly well. Nuclear can load follow, within limitations: https://news.ycombinator.com/item?id=36254716 https://news.ycombinator.com/item?id=36254716
    - tfourb 6mo ago
      > Solar plus batteries can provide synthetic inertia if the incentives/regulations are correctly designed. Yes, but why build nuclear at all, if you are already building PV + batteries? Nuclear is much more expensive than that combination. And if you add nuclear capacity on a level that actually matters (i.e. 30%+ of peak load), you run into real integration problems. As I've written elsewhere, a toke nuclear program can make sense if you want to keep the industrial base, institutional knowledge and expertise around, i.e. to guarantee independent access to nuclear weapons. But it is ludicrous to make nuclear a cornerstone of your energy policy. Not even China is expanding its share of nuclear in total energy generation. They keep it around as a strategic asset, but a subsidized one. For countries like Denmark and Spain I'd be pulling my hair out if my government would start throwing money into the money pit that is nuclear power (and it is inevitably is government money, because no nuclear power plant has ever been built without government subsidies and/or price guarantees). > Nuclear can load follow, within limitations Yes, but it makes zero economic sense to do so. Nuclear is multiple times more expensive per kwh than PV + batteries, even if you run it at max capacity continuously. If you require nuclear to load follow on a regular basis, not a single reactor will ever be built again.
      - robocat 6mo ago
        > Yes, but why build nuclear at all I wasn't suggesting that. Why did you assume that and then argue against something I didn't say?
  - modo_mario 6mo ago

kuerbel 6mo ago

No it's not. Nuclear plants are not compatible with climate change. Spain and it's rivers will be too warm to cool them down: https://www.euronews.com/2025/07/02/france-and-switzerland-shut-down-nuclear-power-plants-amid-scorching-heatwave https://www.euronews.com/2025/07/02/france-and-switzerland-s...

Ekaros 6mo ago
Well only to certain point. When the rivers will naturally be too hot. You can start making them even hotter and it does not matter anymore.
surfaceofthesun 6mo ago
That may require retrofitting the plants to use open loop cooling instead of closed loop. That would increase water consumption.

yayachiken 6mo ago

> It's not that easy, and the 2025 blackout good evidence of that. Renewables need a grid that's engineered for them and that require significative investments. The outage in spain had multiple complex causes. While the grid had a rather routine instability/oscillation on-going during time of the incident, the actual point-of-no-return was completely non-technical: Prices crossed into the negatives, which caused generation to drop by hundreds of megawatts and load to increase likewise within a minute (!) because the price acted as a non-technical synchronized drop-off signal for the grid. In grids where the price action is not forwarded directly to the generators and consumers there would be no incentive to suddenly drop off decentralized generation. So for example in Germany a black-out would not happen like this. You can download the full ENTSO-E report here: https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/#Publications_&_Documents https://www.entsoe.eu/publications/blackout/28-april-2025-ib... (See page 10 for a broad incident timeline) Unfortunately, to have an informed opinion, you pretty much have to read all these pages, because the situation is just so complex. Otherwise, you just fall for agenda pushing from all sides.

phatfish 6mo ago
Yup, its interesting that a community supposedly of "engineers" are happy to claim expert knowledge of domains in which they have no experience.
- yayachiken 6mo ago
  That being said, I was apparently also under the impression of outdated or just plain wrong information. While the report I listed mentions the sudden loss of decentralized generation as starting point of the blackout, and also specifically mentions small-scale rooftop PV, it says that the cause for that sudden synchronized drop-off is actually unknown.
  - robocat 6mo ago
    You can't get an "informed opinion" by reading crap like that report. The Spanish systems have systematic design failures for stability and electricity market design. Working out the political failures that led to the design failures is much harder. Consultancies like https://www.nera.com/capabilities/power--utilities--and-renewables-.html https://www.nera.com/capabilities/power--utilities--and-rene... specialize in advising about electricity networks and market design. Only those working closely in that profession have any knowledge of the underlying causes. Most everyone else (including this comment) is different levels of ignorance and cluelessness. Edit E.g. Crap quote from the report "but no significant oscillations with amplitudes above 20 mHz". The rest of it is about that level from what I could tell.

ViewTrick1002 6mo ago

Please tell me how renewables cause a lack of reactive power. Which was the source of the Iberian blackout. All reasonable grids already force renewables to handle reactive power if they want to connect, like they do for all electricity generation. It is a trivial expense, but still an expense so no one does it unless forced.

adrian_b 6mo ago
In another thread that comments the report it was said that most inverters used in Spain for the renewable energy sources do not implement a control policy to generate an adequate reactive power to compensate the phase fluctuations of the grid, like a synchronous electromechanical generator would do. The inverters only disconnected from the grid when the frequency went outside the permitted range. Ensuring that the inverters produce compensating reactive power would have been easy to do, but it was not done simply because there were no regulations that requested this. Obviously, as a consequence of the report, this is likely to change.
- ViewTrick1002 6mo ago
  Yeah, been trivial forever. In the US it became a requirement for new all utility scale non-synchronous generators a decade ago. And then a bunch of statewide rules for rooftop solar as well. https://www.ferc.gov/news-events/news/ferc-moves-implement-fast-act-provisions-critical-infrastructure-information https://www.ferc.gov/news-events/news/ferc-moves-implement-f...