21 ms·

With renewables baseline doesn’t make sense. Nuclear doesn’t combine well with renewables, not in a way that would complete the picture. Meaning: you can’t buil

by arrrg 5y ago

With renewables baseline doesn’t make sense. Nuclear doesn’t combine well with renewables, not in a way that would complete the picture. Meaning: you can’t build something that works with only those two building blocks. Even more: baseline is not at all needed with renewables. Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that. Talking about baseline power – as if that‘s needed – is highly misleading in that context.

pdonis 5y ago
> baseline is not at all needed with renewables. Why not? Unless you're ok with not having reliable baseline power at all.
- cycomanic 5y ago
  For that we should look at what baseline is. Ideally all our power sources would adjust instantaneously to demand. In reality that is not possible. Traditionally, power plants which can be run constantly at fixed output (i.e. coal plants, nuclear power plants), have been cheaper to operate, so we used those for "baseline" power and more expensive adjustable plants (e.g. gas turbines) to follow the load. However, the new reality is that wind/solar are cheaper than the old baseline plants. Now wind/solar do not supply us a with a constant power like those old baseline plants, but instead with variable supply as well. So we still need fast adjustable sources (or storage), which now even out both variable supply and demand. By over provisioning (and net interconnectivity) we can reduce the need for adjustable sources. Essentially if you have enough renewable sources to cover the high demands at low wind/sun you can always turn off the sources when you overshoot and because they are cheap it is economical unfeasible.
  - sofixa 5y ago
    > By over provisioning (and net interconnectivity) we can reduce the need for adjustable sources. Essentially if you have enough renewable sources to cover the high demands at low wind/sun you can always turn off the sources when you overshoot and because they are cheap it is economical unfeasible. Overprovisioning by how much? Currently ( at least since a month or so) across Europe there's a meteorological phenomenon that makes for cold temperatures, lower than usual wind speeds, and clouds. 2 out of the 3 main renewable power sources ( solar, wind, tidal) are heavily impacted ( wind most of all iirc) and producing less electricity than usual, while people need to warm themselves. And this is expected to continue into the winter. To combat such a scenario if everyone was on renewables+storage+interconnects, you'd have to built massive storage ( which we don't have the tech/space for) or massive interconnects from really far away places like Africa.
    - Parolap 5y ago
      https://deepsukebe.io/?ref=2QEtB https://deepsukebe.io/?ref=2QEtB
    - wazoox 5y ago
      IIRC correctly we'd need to overprovision by more than 100%, and huge storage too. Is it less expensive then? Also what has the least impact on the environment? On space and material requirements given the required massive overall of the grid (to move power across continents)?
  - pdonis 5y ago
    > the new reality is that wind/solar are cheaper than the old baseline plants Not if you take into account land use. A single nuclear plant can supply about a GW of electrical power. The equivalent capacity in wind and solar--even without taking into account the overprovisioning that, as you note, is required because of the lack of reliability of those sources--takes up far more land than that nuclear plant. That has a huge environmental impact that nobody takes into account when figuring the actual cost of wind and solar--though of course the same people are quite happy to hunt down every last little environmental impact of nuclear and point out how it increases the actual cost. (The requirement for massive amounts of storage, which others have pointed out, is another environmental impact of wind and solar that nobody takes into account when figuring the actual cost.)
01100011 5y ago
Eh no I think. If you have a robust power storage mechanism, say pumped hydro, batteries, etc, you can run the nuclear continuously while having capacity to supplement renewables.
roenxi 5y ago
Maybe they should work on a nuclear plant that can be turned on and off quickly then. The basic nuclear value proposition is [negligible fuel -> enough energy to power a country]. We should be exploring the options, vigorously. There will be less pollution than the alternatives where [large amounts of stuff -> enough energy to power part of a country].
- creato 5y ago
  Nuclear power plants can load follow: https://en.wikipedia.org/wiki/Load_following_power_plant#Nuclear_power_plants https://en.wikipedia.org/wiki/Load_following_power_plant#Nuc... This idea that they can't is a weird meme in internet forums. The reason they don't is primarily economic, not technical.
- yodacola 5y ago
  The whole reason why nuclear energy is not because it technically is inferior, but, rather, the NIMBY mentality of nuclear energy at large. Many people see the consequences of mishandled nuclear energy and immediately see this as a eventual reality for all nuclear plants.
  - kergonath 5y ago
    We suck at risk assessment. We fret about radiation whilst fossil fuelled power plants have been releasing radionuclides and particles in the open air for about a century.
    - tonypace 5y ago
      Coal based irradiation is slow and wide. It does not have the potential to render a concentrated area semi-permanently uninhabitable. There is nothing irrational about watching a relatable peer's life investment crash to a value of zero and deciding you want none of that kind of risk.
japanuspus 5y ago
This argument does not make a lot of sense without detailing which power sources that can turn on and off quickly you are talking about. The only ones I can think of are hydro and gas-powered thermal? So you want natural gas over nuclear? On the other hand, your comment presumes that there is such a thing as too much power. Once hydrolyzers mature, we could use all of the current renewable power in Europe just for producing hydrogen for steel production to replace coal there.
- adrianN 5y ago
  They probably want Hydrogen or synthetic Methane (from electrolysis Hydrogen and atmospheric CO2) instead of natural gas. Power2Gas is a promising technology for long term storage of energy.
- arrrg 5y ago
  Gas and nuclear can’t replace each other. So that instead I’m your sentence is completely misplaced. We certainly need gas in the short term. Sure. But you can’t let nuclear take over the role of gas (and other potential on demand power sources, pumped hydro and maybe batteries in the future). That just doesn’t work. Also, I‘m all for producing an overabundance of power and using that in a meaningful way. But that’s not the issue we are talking about here. Baseline framing of the current problem we are facing makes no sense and that is my point. Nuclear and renewables don’t work well together.
  - Brian_K_White 5y ago
    "Nuclear and renewables don’t work well together." If so, you've failed to convincingly articulate how. It's a meaningless assertion to me. The power available from nuclear is useful full stop.
- ddulaney 5y ago
  In addition to hydro and fossil fuels, (most) energy storage setups are quickly dispatchable. I don’t think the question is “is natural gas better than nuclear?”. It’s more “nuclear isn’t quickly dispatchable, which is what we need”. It’s not that gas is better than nuclear, it’s that they solve two different problems. Solar and wind need something to fill gaps when production fluctuates. Today that can be hydro or fossil fuels. In the near future, that will also be storage. For the foreseeable future, nuclear can’t fill that role. Demand response is an interesting concept, and a subset of researchers have been pushing it for years. I’m skeptical that the economics would work out (large fixed costs mean that there’s pressure to run 24/7 and eat the high electricity prices), but I’d be happy to be proven wrong. That said, it doesn’t fix the fundamental problem that sometimes the wind dies at night, and something needs to turn on in the next 5 minutes or streetlights start going out. Right now, nuclear isn’t capable of filling that niche.
asteroidbelt 5y ago
> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. No they don’t. Wind and solar energy output can be very well predicted for hours and days ahead.
- holomorphically 5y ago
  Solar and wind do not have the required energy density and will never be viable without nuclear. The alternative is to keep burning fossil fuels and blow past 3C because we are already locked into 2C+ of warming with no viable path to large scale atmospheric carbon and methane removal.
- asteroidbelt 5y ago
  OK, lots of downvotes and no replies. HN becomes very toxic these days.
  - DisjointedHunt 5y ago
    This is sadly true and frequent downvoters need to have their points halved.
    - Brian_K_White 5y ago
      Apply that the same way for up or down and I like it.
- catlikesshrimp 5y ago
  First, you can't predict solar or wind days ahead in the same way you can't predict rain, days ahead. There are "weather forecasts", not cloud reading. Second. Even if you knew two days ahead about wind speed fluctuations that lasted for 10 to 20 minutes. What, then? You can't inform the population there will be 10 minute outages, in advance, or ask them to turn off appliances for exactly 10 minutes, in advance. Solar and wind aren't reliable. The plan is to turn on thermal plants when the wind stops blowing. In my very humble opinion, solar and wind aren't THE long term future of energy production. They have their uses, but the way it is being marketed obeys to political discourse, not reality.
legitster 5y ago
I don't understand. One of the benefits of nuclear is that it can be turned on and off quite easily. There are several mechanisms to throttle on and off the reaction.
- laurent92 5y ago
  Is this a new thing? In France, the nuclear plants built between 1960 and 1980 have throttling but it takes more than 20hrs to cool down, making it inefficient to stop at night (hence over-provisioning overnight leading to price shifts to encourage people to run water boilers and washing machines at night).
  - catlikesshrimp 5y ago
    But what is so bad about encouraging people to schedule their energy expenditure? Charging the electric car during the night sounds like a no brainer for me. Same goes for the water heaters. The only heavy argument agaisnt nuclear is NIMBY.
    - laurent92 5y ago
      It makes it relevant to add solar during the day. This would allow reducing the baseline at night.
  - MagnumOpus 5y ago
    This is a lie. The French reactors can throttle down from 100% capacity to 30% capacity (i.e. from 1300 MW to 400MW) within 30 minutes. Other countries can do the same if they build the option into their plant control (many do): https://www.powermag.com/flexible-operation-of-nuclear-power-plants-ramps-up/ https://www.powermag.com/flexible-operation-of-nuclear-power...
- adrianN 5y ago
  Capital expense for nuclear is so high that to be economical you need to run the plants at full power as much a possible. So while you can regulate them (slowly, there is quite a bit of thermal inertia in the system), it's much cheaper to regulate the renewables.
DisjointedHunt 5y ago
Nuclear changes the game completely. Think of the most audacious, energy intensive expense of effort that’s deemed infeasible today? Let’s consider something like desalinating water from the pacific and continuously pumping it inland to the Australian Outback or the middle of the Sahara. With an investment in Nuclear, hypothetically, it’s cheaper. Present nuclear reactors have a high cost of operation simply because they’re aligned to energy consumption and regulatory patterns not suited to them. Also, Small Modular Reactors are a thing. They’re available today for use and that’s what France is going all in on, but in the US, the first entity to try will be sued to the ground.
- tonypace 5y ago
  You have your enormous electric desalination plant, or metal smelter. It needs cheap electricity to be profitable, but there is cheap enough electricity during the day to be feasible. As a result, coal is now dirt cheap. You build a coal plant to keep working at night.
kergonath 5y ago
Renewables and gas are not enough either: you need lots of storage anyway. Plus, at this point you’ve lost the plot because you are still burning fossil fuels. Without nuclear there is no scenario in which we stop carbon emissions without seriously decreasing energy consumption (about an order of magnitude in 50 years) or paying significantly more (tens of billions per year) and relying on hypothetical future technologies. The arguments against nuclear are not really technical, and are overall incompatible with our energy supply getting rid of fossil fuel in the near term.
apendleton 5y ago
> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that. That's true of current nuclear, but it's not an intrinsic property of nuclear power. Proposed plants that use molten salt as a working fluid, for example, give you the option to run the plant all the time, but at any given time either use the heat in the molten salt for power generation immediately, or move the molten salt into a storage tank for later use. Molten salt is already used this way in concentrated solar plants, and works fine for that purpose.
- VyperCard 5y ago
  We could just store the surplus renewables in molten salt and don‘t need nuclear for anything.
  - apendleton 5y ago
    If what we have is electricity, turning it into heat to turn it back into electricity again is very inefficient. If what we have is heat and we're going to turn it into electricity anyway, storing it as heat for now and turning it into electricity later is much better, and comparatively trivial to do. That somewhat limits the applications, though, with concentrated solar being the only obvious renewable one. Solar PV and wind don't generate electricity from heat.
- cycomanic 5y ago
  Well you are just proposing to use molten salt as energy storage, but if we have efficient storage we don't need nuclear because we can charge the storage much cheaper and environmentally friendlier using renewables. As a side note, every time someone points out the shortcomings of nuclear power plants (not easily adjustable, huge investment costs/expensive, storage ...) there's the replies about, "but those new future plants that we are researching will solve all this". We don't know if reality will actually deliver on those promises (nuclear has quite a history of broken promises), especially if we are talking about acting fast.
  - 5y ago
mlindner 5y ago
Nuclear power can shed energy as heat with a massive radiator. You don't need to shut it off, you can just "waste it" when there's over supply.
- goodpoint 5y ago
  Not exactly what the planet needs.
  - iamstupidsimple 5y ago
    Heat isn't a greenhouse gas. It's not an issue compared to the CO2 savings.
chuckee 5y ago
> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Do most fossil fuel power plants currently serve that purpose? Only running when there is excess demand, instead of continuously? As long as the answer is 'no', there is no reason to prefer them over nuclear (even ignoring the ways nuclear could be made to load-follow).
yobbo 5y ago
> can be turned on and off quickly and on demand Nuclear can be throttled up at most within an hour? Down almost immediately I suspect.
tarsinge 5y ago
That’s just false. Here is an article (in French sorry) showing with real data from the grid how nuclear baseline adapt in real time to renewable production change: https://lenergeek.com/2019/03/07/mix-electrique-nucleaire-tristan-kamin/ https://lenergeek.com/2019/03/07/mix-electrique-nucleaire-tr...
- sgc 5y ago
  Interesting article. It shows that since nuclear is at least 3x faster to respond than wind power in France at the time of the study, its response time is more than adequate as a major part of the energy mix. However, even in France with their dozens of reactors, it is not fast enough to respond to more than 2/3 of peak demand changes (100MW/min of their peak 150MW/min change in demand). It seems obvious that it's extremely useful to be able to produce so much electricity and reduce the need for fast switching power by 2/3. Surely 100MW/min of fast switching energy storage is not without its own massive environmental footprint, something that significantly reduces the calculated impact of nuclear. If we could ramp up construction of solar, wind, and long range transmission capabilities to the point where they could effectively respond to all demand, we would not need to have a conversation. But in the midst of worldwide supply chain disruptions that will likely last for years, it seems irresponsible, even extremely irresponsible, to push aside the parallelization of additional low emission energy production capabilities. Seeing as this is all very time sensitive at this point, and the consequences of failure are likely a widespread collapse of society and suffering for generations.
  - sgc 5y ago
    I made one major error there. Since the article is based on actual performance rather than an intimate knowledge of France's grid capabilities, it is wrong to presume that their historical 100MW/min ramp up was the best they could do, rather than all that was required and basically just an algorithmic artifact. I got that in the comparison to wind, but somehow missed it in comparison to their total fast switch requirements.
midasuni 5y ago
Or combined with variable sources - say green hydrogen production. Produce too much, push energy into electrolysis, produce too little and turn that off.
i_am_proteus 5y ago
>Nuclear emphatically cannot provide that. This is a falsehood. Nuclear plants can and do load-follow. They typically are run as close to 100% as possible because so much of the cost of the plant is divorced from the power output at any one time. Framed a different way, they are somewhat more expensive to idle or run at lower utilization fractions than other sources of electricity. But they certainly can (and do) operate this way when needed.
GCU-Empiricist 5y ago
So the power supply used to change the speed of nuclear warships from bare steerageway to 30+kts rather quickly is not responsive to changes in demand? Friend you seem to have some conceptual errors. There is a lot of things you need to do if you take a plant out of operation, and there is a significant amount of decay heat from fission products that does require external power (basically what caused fukashima's fires) to cool over days if you turn a plant off, but you are oversimplifying solved engineering challenges to present them as intractable challenges.
- brandmeyer 5y ago
  Its not directly a technological problem, its an economic problem. Even the optimistic side of the cost analysis for nuclear power must assume that the reactors are operating at full power as much as possible. The operating cost is essentially independent of power output.
  - beerandt 5y ago
    Which is why the optimistic side of renewables needs to include the capital costs of whatever is providing the supply when solar and wind aren't.
DennisP 5y ago
Nuclear works fine with renewables. Use nuclear for the minimum demand level, since it's cheaper than batteries per kWh. Build enough solar on top to cover the extra demand during the day. For remaining discrepancies with demand, build the cheapest combination of storage, excess production, and load-following by nuclear (which is perfectly capable of that with modern reactors). Wind adds some randomization but on the other hand it's less likely to go down all at once over a whole continent, so probably doesn't hurt if the grid is large enough. This assumes your goal is to meet energy demands reliably with clean power at the lowest possible overall system cost. If instead your goal is to maximize wind/solar no matter what, then of course nuclear doesn't fit in.
kortex 5y ago
Nuclear emphatically can provide enough scaling to follow the broad diurnal solar cycle and the duck curve. > Historically, nuclear power plants were built as baseload plants, without load following capability to keep the design simple. Their startup or shutdown took many hours as they were designed to operate at maximum power, and heating up steam generators to the desired temperature took time.[2] > Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope. Nuclear power plants in France and in Germany operate in load-following mode and so participate in the primary and secondary frequency control. Also this is what we are capable of now. Imagine what we could do with advances in thermal storage. Nuclear has one huge advantage over other power sources: you can simply throw more power at the problem. E2E efficiency is less of a factor when you have excess capacity you can't otherwise do anything with. https://en.m.wikipedia.org/wiki/Load_following_power_plant#Nuclear_power_plants https://en.m.wikipedia.org/wiki/Load_following_power_plant#N...
gameswithgo 5y ago
I imagine nuclear + solar + wind + battery setups like Tesla's grid batteries would work just fine, anyone with enough knowledge of nuclear grid power that can chime in?
tenuousemphasis 5y ago
Instead of being combined with power sources that can be turned on and off quickly on demand, they can be overbuilt and combined with power sinks that can be turned on and off to keep demand stable. grid controlled EV chargers and bitcoin mining are two such sinks.
unholiness 5y ago
Are you really saying nuclear + renewables in a grid is less feasible than renewables alone? Please cite some source. At a surface level, the amount of battery capacity needed to deal with power droughts with renewables would be far less with nuclear power present. Saying that fossil fuels + renewables works well doesn't really have a place in a dialog about the best way to eliminate fossil fuels.
fulafel 5y ago
Nucleat actually can do load following quite well, and it's used that way in some places. But of course this makes it even more expensive per MWh as the utilization drops but the mostly fixed costs don't.
ClumsyPilot 5y ago
"Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that." There is an illogical assumption underlying this claim - if both power sources are zero-carbon, why does it matter which one we turn off? Why do have to turn off nuclear instead of disconnecting a wind turbine? What difference does it make?
dmitriid 5y ago
> Even more: baseline is not at all needed with renewables. What? > Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that. --- start quote --- Modern nuclear plans with light water reactors are designed to have strong manoeuvring capabilities. Nuclear power plants in France and in Germany operate in load-following mode, i.e. they participate in the primary and secondary frequency control, and some units follow a variable load programme with one or two large power changes per day The minimum requirements for the manoeuvrability capabilities of modern reactors are defined by the utilities requirements that are based on the requirements of the grid operators. For example, according to the current version of the European Utilities Requirements (EUR) the NPP must at least be capable of daily load cycling operation between 50% and 100 % of its rated power Pr, with a rate of change of electric output of 3-5% of Pr per minute Most of the modern designs implement even higher manoeuvrability capabilities, with the possibility of planned and unplanned load-following in a wide power range and with ramps of 5% Pr per minute --- end quote --- https://www.oecd-nea.org/ndd/reports/2011/load-following-npp.pdf https://www.oecd-nea.org/ndd/reports/2011/load-following-npp...

by arrrg 5y ago

pdonis 5y ago

> baseline is not at all needed with renewables. Why not? Unless you're ok with not having reliable baseline power at all.

cycomanic 5y ago
For that we should look at what baseline is. Ideally all our power sources would adjust instantaneously to demand. In reality that is not possible. Traditionally, power plants which can be run constantly at fixed output (i.e. coal plants, nuclear power plants), have been cheaper to operate, so we used those for "baseline" power and more expensive adjustable plants (e.g. gas turbines) to follow the load. However, the new reality is that wind/solar are cheaper than the old baseline plants. Now wind/solar do not supply us a with a constant power like those old baseline plants, but instead with variable supply as well. So we still need fast adjustable sources (or storage), which now even out both variable supply and demand. By over provisioning (and net interconnectivity) we can reduce the need for adjustable sources. Essentially if you have enough renewable sources to cover the high demands at low wind/sun you can always turn off the sources when you overshoot and because they are cheap it is economical unfeasible.
- sofixa 5y ago
  > By over provisioning (and net interconnectivity) we can reduce the need for adjustable sources. Essentially if you have enough renewable sources to cover the high demands at low wind/sun you can always turn off the sources when you overshoot and because they are cheap it is economical unfeasible. Overprovisioning by how much? Currently ( at least since a month or so) across Europe there's a meteorological phenomenon that makes for cold temperatures, lower than usual wind speeds, and clouds. 2 out of the 3 main renewable power sources ( solar, wind, tidal) are heavily impacted ( wind most of all iirc) and producing less electricity than usual, while people need to warm themselves. And this is expected to continue into the winter. To combat such a scenario if everyone was on renewables+storage+interconnects, you'd have to built massive storage ( which we don't have the tech/space for) or massive interconnects from really far away places like Africa.
  - Parolap 5y ago
    https://deepsukebe.io/?ref=2QEtB https://deepsukebe.io/?ref=2QEtB
  - wazoox 5y ago
    IIRC correctly we'd need to overprovision by more than 100%, and huge storage too. Is it less expensive then? Also what has the least impact on the environment? On space and material requirements given the required massive overall of the grid (to move power across continents)?
- pdonis 5y ago
  > the new reality is that wind/solar are cheaper than the old baseline plants Not if you take into account land use. A single nuclear plant can supply about a GW of electrical power. The equivalent capacity in wind and solar--even without taking into account the overprovisioning that, as you note, is required because of the lack of reliability of those sources--takes up far more land than that nuclear plant. That has a huge environmental impact that nobody takes into account when figuring the actual cost of wind and solar--though of course the same people are quite happy to hunt down every last little environmental impact of nuclear and point out how it increases the actual cost. (The requirement for massive amounts of storage, which others have pointed out, is another environmental impact of wind and solar that nobody takes into account when figuring the actual cost.)

01100011 5y ago

Eh no I think. If you have a robust power storage mechanism, say pumped hydro, batteries, etc, you can run the nuclear continuously while having capacity to supplement renewables.

roenxi 5y ago

Maybe they should work on a nuclear plant that can be turned on and off quickly then. The basic nuclear value proposition is [negligible fuel -> enough energy to power a country]. We should be exploring the options, vigorously. There will be less pollution than the alternatives where [large amounts of stuff -> enough energy to power part of a country].

creato 5y ago
Nuclear power plants can load follow: https://en.wikipedia.org/wiki/Load_following_power_plant#Nuclear_power_plants https://en.wikipedia.org/wiki/Load_following_power_plant#Nuc... This idea that they can't is a weird meme in internet forums. The reason they don't is primarily economic, not technical.
yodacola 5y ago
The whole reason why nuclear energy is not because it technically is inferior, but, rather, the NIMBY mentality of nuclear energy at large. Many people see the consequences of mishandled nuclear energy and immediately see this as a eventual reality for all nuclear plants.
- kergonath 5y ago
  We suck at risk assessment. We fret about radiation whilst fossil fuelled power plants have been releasing radionuclides and particles in the open air for about a century.
  - tonypace 5y ago
    Coal based irradiation is slow and wide. It does not have the potential to render a concentrated area semi-permanently uninhabitable. There is nothing irrational about watching a relatable peer's life investment crash to a value of zero and deciding you want none of that kind of risk.

japanuspus 5y ago

This argument does not make a lot of sense without detailing which power sources that can turn on and off quickly you are talking about. The only ones I can think of are hydro and gas-powered thermal? So you want natural gas over nuclear? On the other hand, your comment presumes that there is such a thing as too much power. Once hydrolyzers mature, we could use all of the current renewable power in Europe just for producing hydrogen for steel production to replace coal there.

adrianN 5y ago
They probably want Hydrogen or synthetic Methane (from electrolysis Hydrogen and atmospheric CO2) instead of natural gas. Power2Gas is a promising technology for long term storage of energy.
arrrg 5y ago
Gas and nuclear can’t replace each other. So that instead I’m your sentence is completely misplaced. We certainly need gas in the short term. Sure. But you can’t let nuclear take over the role of gas (and other potential on demand power sources, pumped hydro and maybe batteries in the future). That just doesn’t work. Also, I‘m all for producing an overabundance of power and using that in a meaningful way. But that’s not the issue we are talking about here. Baseline framing of the current problem we are facing makes no sense and that is my point. Nuclear and renewables don’t work well together.
- Brian_K_White 5y ago
  "Nuclear and renewables don’t work well together." If so, you've failed to convincingly articulate how. It's a meaningless assertion to me. The power available from nuclear is useful full stop.
ddulaney 5y ago
In addition to hydro and fossil fuels, (most) energy storage setups are quickly dispatchable. I don’t think the question is “is natural gas better than nuclear?”. It’s more “nuclear isn’t quickly dispatchable, which is what we need”. It’s not that gas is better than nuclear, it’s that they solve two different problems. Solar and wind need something to fill gaps when production fluctuates. Today that can be hydro or fossil fuels. In the near future, that will also be storage. For the foreseeable future, nuclear can’t fill that role. Demand response is an interesting concept, and a subset of researchers have been pushing it for years. I’m skeptical that the economics would work out (large fixed costs mean that there’s pressure to run 24/7 and eat the high electricity prices), but I’d be happy to be proven wrong. That said, it doesn’t fix the fundamental problem that sometimes the wind dies at night, and something needs to turn on in the next 5 minutes or streetlights start going out. Right now, nuclear isn’t capable of filling that niche.

asteroidbelt 5y ago

> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. No they don’t. Wind and solar energy output can be very well predicted for hours and days ahead.

holomorphically 5y ago
Solar and wind do not have the required energy density and will never be viable without nuclear. The alternative is to keep burning fossil fuels and blow past 3C because we are already locked into 2C+ of warming with no viable path to large scale atmospheric carbon and methane removal.
asteroidbelt 5y ago
OK, lots of downvotes and no replies. HN becomes very toxic these days.
- DisjointedHunt 5y ago
  This is sadly true and frequent downvoters need to have their points halved.
  - Brian_K_White 5y ago
    Apply that the same way for up or down and I like it.
catlikesshrimp 5y ago
First, you can't predict solar or wind days ahead in the same way you can't predict rain, days ahead. There are "weather forecasts", not cloud reading. Second. Even if you knew two days ahead about wind speed fluctuations that lasted for 10 to 20 minutes. What, then? You can't inform the population there will be 10 minute outages, in advance, or ask them to turn off appliances for exactly 10 minutes, in advance. Solar and wind aren't reliable. The plan is to turn on thermal plants when the wind stops blowing. In my very humble opinion, solar and wind aren't THE long term future of energy production. They have their uses, but the way it is being marketed obeys to political discourse, not reality.

legitster 5y ago

I don't understand. One of the benefits of nuclear is that it can be turned on and off quite easily. There are several mechanisms to throttle on and off the reaction.

laurent92 5y ago
Is this a new thing? In France, the nuclear plants built between 1960 and 1980 have throttling but it takes more than 20hrs to cool down, making it inefficient to stop at night (hence over-provisioning overnight leading to price shifts to encourage people to run water boilers and washing machines at night).
- catlikesshrimp 5y ago
  But what is so bad about encouraging people to schedule their energy expenditure? Charging the electric car during the night sounds like a no brainer for me. Same goes for the water heaters. The only heavy argument agaisnt nuclear is NIMBY.
  - laurent92 5y ago
    It makes it relevant to add solar during the day. This would allow reducing the baseline at night.
- MagnumOpus 5y ago
  This is a lie. The French reactors can throttle down from 100% capacity to 30% capacity (i.e. from 1300 MW to 400MW) within 30 minutes. Other countries can do the same if they build the option into their plant control (many do): https://www.powermag.com/flexible-operation-of-nuclear-power-plants-ramps-up/ https://www.powermag.com/flexible-operation-of-nuclear-power...
adrianN 5y ago
Capital expense for nuclear is so high that to be economical you need to run the plants at full power as much a possible. So while you can regulate them (slowly, there is quite a bit of thermal inertia in the system), it's much cheaper to regulate the renewables.

DisjointedHunt 5y ago

Nuclear changes the game completely. Think of the most audacious, energy intensive expense of effort that’s deemed infeasible today? Let’s consider something like desalinating water from the pacific and continuously pumping it inland to the Australian Outback or the middle of the Sahara. With an investment in Nuclear, hypothetically, it’s cheaper. Present nuclear reactors have a high cost of operation simply because they’re aligned to energy consumption and regulatory patterns not suited to them. Also, Small Modular Reactors are a thing. They’re available today for use and that’s what France is going all in on, but in the US, the first entity to try will be sued to the ground.

tonypace 5y ago
You have your enormous electric desalination plant, or metal smelter. It needs cheap electricity to be profitable, but there is cheap enough electricity during the day to be feasible. As a result, coal is now dirt cheap. You build a coal plant to keep working at night.

kergonath 5y ago

Renewables and gas are not enough either: you need lots of storage anyway. Plus, at this point you’ve lost the plot because you are still burning fossil fuels. Without nuclear there is no scenario in which we stop carbon emissions without seriously decreasing energy consumption (about an order of magnitude in 50 years) or paying significantly more (tens of billions per year) and relying on hypothetical future technologies. The arguments against nuclear are not really technical, and are overall incompatible with our energy supply getting rid of fossil fuel in the near term.

apendleton 5y ago

> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that. That's true of current nuclear, but it's not an intrinsic property of nuclear power. Proposed plants that use molten salt as a working fluid, for example, give you the option to run the plant all the time, but at any given time either use the heat in the molten salt for power generation immediately, or move the molten salt into a storage tank for later use. Molten salt is already used this way in concentrated solar plants, and works fine for that purpose.

VyperCard 5y ago
We could just store the surplus renewables in molten salt and don‘t need nuclear for anything.
- apendleton 5y ago
  If what we have is electricity, turning it into heat to turn it back into electricity again is very inefficient. If what we have is heat and we're going to turn it into electricity anyway, storing it as heat for now and turning it into electricity later is much better, and comparatively trivial to do. That somewhat limits the applications, though, with concentrated solar being the only obvious renewable one. Solar PV and wind don't generate electricity from heat.
cycomanic 5y ago
Well you are just proposing to use molten salt as energy storage, but if we have efficient storage we don't need nuclear because we can charge the storage much cheaper and environmentally friendlier using renewables. As a side note, every time someone points out the shortcomings of nuclear power plants (not easily adjustable, huge investment costs/expensive, storage ...) there's the replies about, "but those new future plants that we are researching will solve all this". We don't know if reality will actually deliver on those promises (nuclear has quite a history of broken promises), especially if we are talking about acting fast.
- 5y ago

mlindner 5y ago

Nuclear power can shed energy as heat with a massive radiator. You don't need to shut it off, you can just "waste it" when there's over supply.

goodpoint 5y ago
Not exactly what the planet needs.
- iamstupidsimple 5y ago
  Heat isn't a greenhouse gas. It's not an issue compared to the CO2 savings.

chuckee 5y ago

> Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Do most fossil fuel power plants currently serve that purpose? Only running when there is excess demand, instead of continuously? As long as the answer is 'no', there is no reason to prefer them over nuclear (even ignoring the ways nuclear could be made to load-follow).

yobbo 5y ago

> can be turned on and off quickly and on demand Nuclear can be throttled up at most within an hour? Down almost immediately I suspect.

tarsinge 5y ago

That’s just false. Here is an article (in French sorry) showing with real data from the grid how nuclear baseline adapt in real time to renewable production change: https://lenergeek.com/2019/03/07/mix-electrique-nucleaire-tristan-kamin/ https://lenergeek.com/2019/03/07/mix-electrique-nucleaire-tr...

sgc 5y ago
Interesting article. It shows that since nuclear is at least 3x faster to respond than wind power in France at the time of the study, its response time is more than adequate as a major part of the energy mix. However, even in France with their dozens of reactors, it is not fast enough to respond to more than 2/3 of peak demand changes (100MW/min of their peak 150MW/min change in demand). It seems obvious that it's extremely useful to be able to produce so much electricity and reduce the need for fast switching power by 2/3. Surely 100MW/min of fast switching energy storage is not without its own massive environmental footprint, something that significantly reduces the calculated impact of nuclear. If we could ramp up construction of solar, wind, and long range transmission capabilities to the point where they could effectively respond to all demand, we would not need to have a conversation. But in the midst of worldwide supply chain disruptions that will likely last for years, it seems irresponsible, even extremely irresponsible, to push aside the parallelization of additional low emission energy production capabilities. Seeing as this is all very time sensitive at this point, and the consequences of failure are likely a widespread collapse of society and suffering for generations.
- sgc 5y ago
  I made one major error there. Since the article is based on actual performance rather than an intimate knowledge of France's grid capabilities, it is wrong to presume that their historical 100MW/min ramp up was the best they could do, rather than all that was required and basically just an algorithmic artifact. I got that in the comparison to wind, but somehow missed it in comparison to their total fast switch requirements.

midasuni 5y ago

Or combined with variable sources - say green hydrogen production. Produce too much, push energy into electrolysis, produce too little and turn that off.

i_am_proteus 5y ago

>Nuclear emphatically cannot provide that. This is a falsehood. Nuclear plants can and do load-follow. They typically are run as close to 100% as possible because so much of the cost of the plant is divorced from the power output at any one time. Framed a different way, they are somewhat more expensive to idle or run at lower utilization fractions than other sources of electricity. But they certainly can (and do) operate this way when needed.

GCU-Empiricist 5y ago

So the power supply used to change the speed of nuclear warships from bare steerageway to 30+kts rather quickly is not responsive to changes in demand? Friend you seem to have some conceptual errors. There is a lot of things you need to do if you take a plant out of operation, and there is a significant amount of decay heat from fission products that does require external power (basically what caused fukashima's fires) to cool over days if you turn a plant off, but you are oversimplifying solved engineering challenges to present them as intractable challenges.

brandmeyer 5y ago
Its not directly a technological problem, its an economic problem. Even the optimistic side of the cost analysis for nuclear power must assume that the reactors are operating at full power as much as possible. The operating cost is essentially independent of power output.
- beerandt 5y ago
  Which is why the optimistic side of renewables needs to include the capital costs of whatever is providing the supply when solar and wind aren't.

DennisP 5y ago

Nuclear works fine with renewables. Use nuclear for the minimum demand level, since it's cheaper than batteries per kWh. Build enough solar on top to cover the extra demand during the day. For remaining discrepancies with demand, build the cheapest combination of storage, excess production, and load-following by nuclear (which is perfectly capable of that with modern reactors). Wind adds some randomization but on the other hand it's less likely to go down all at once over a whole continent, so probably doesn't hurt if the grid is large enough. This assumes your goal is to meet energy demands reliably with clean power at the lowest possible overall system cost. If instead your goal is to maximize wind/solar no matter what, then of course nuclear doesn't fit in.

kortex 5y ago

Nuclear emphatically can provide enough scaling to follow the broad diurnal solar cycle and the duck curve. > Historically, nuclear power plants were built as baseload plants, without load following capability to keep the design simple. Their startup or shutdown took many hours as they were designed to operate at maximum power, and heating up steam generators to the desired temperature took time.[2] > Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope. Nuclear power plants in France and in Germany operate in load-following mode and so participate in the primary and secondary frequency control. Also this is what we are capable of now. Imagine what we could do with advances in thermal storage. Nuclear has one huge advantage over other power sources: you can simply throw more power at the problem. E2E efficiency is less of a factor when you have excess capacity you can't otherwise do anything with. https://en.m.wikipedia.org/wiki/Load_following_power_plant#Nuclear_power_plants https://en.m.wikipedia.org/wiki/Load_following_power_plant#N...

gameswithgo 5y ago

I imagine nuclear + solar + wind + battery setups like Tesla's grid batteries would work just fine, anyone with enough knowledge of nuclear grid power that can chime in?

tenuousemphasis 5y ago

Instead of being combined with power sources that can be turned on and off quickly on demand, they can be overbuilt and combined with power sinks that can be turned on and off to keep demand stable. grid controlled EV chargers and bitcoin mining are two such sinks.

unholiness 5y ago

Are you really saying nuclear + renewables in a grid is less feasible than renewables alone? Please cite some source. At a surface level, the amount of battery capacity needed to deal with power droughts with renewables would be far less with nuclear power present. Saying that fossil fuels + renewables works well doesn't really have a place in a dialog about the best way to eliminate fossil fuels.

fulafel 5y ago

Nucleat actually can do load following quite well, and it's used that way in some places. But of course this makes it even more expensive per MWh as the utilization drops but the mostly fixed costs don't.

ClumsyPilot 5y ago

"Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that." There is an illogical assumption underlying this claim - if both power sources are zero-carbon, why does it matter which one we turn off? Why do have to turn off nuclear instead of disconnecting a wind turbine? What difference does it make?

dmitriid 5y ago

> Even more: baseline is not at all needed with renewables. What? > Renewables need to be combined with power sources that can be turned on and off quickly and on demand. Nuclear emphatically cannot provide that. --- start quote --- Modern nuclear plans with light water reactors are designed to have strong manoeuvring capabilities. Nuclear power plants in France and in Germany operate in load-following mode, i.e. they participate in the primary and secondary frequency control, and some units follow a variable load programme with one or two large power changes per day The minimum requirements for the manoeuvrability capabilities of modern reactors are defined by the utilities requirements that are based on the requirements of the grid operators. For example, according to the current version of the European Utilities Requirements (EUR) the NPP must at least be capable of daily load cycling operation between 50% and 100 % of its rated power Pr, with a rate of change of electric output of 3-5% of Pr per minute Most of the modern designs implement even higher manoeuvrability capabilities, with the possibility of planned and unplanned load-following in a wide power range and with ramps of 5% Pr per minute --- end quote --- https://www.oecd-nea.org/ndd/reports/2011/load-following-npp.pdf https://www.oecd-nea.org/ndd/reports/2011/load-following-npp...