Balancing nuclear and renewable energy

Solar panels now are on the property of the closed Rancho Seco Nuclear Generating Station, near Sacramento, CA. Feb. 2009 Image: Wikipedia

By Cathy Milostan, Argonne National Laboratory

Nuclear power plants typically run either at full capacity or not at all. Yet the plants have the technical ability to adjust to the changing demand for power and thus better accommodate sources of renewable energy such as wind or solar power.

Researchers from the U.S. Department of Energy’s (DOE) Argonne National Laboratory and the Massachusetts Institute of Technology recently explored the benefits of doing just that. If nuclear plants generated power in a more flexible manner, the researchers say, the plants could lower electricity costs for consumers, enable the use of more renewable energy, improve the economics of nuclear energy and help reduce greenhouse gas emissions.

The new study “gives us tools to further explore potential benefits of flexible nuclear operations to work in tandem with greater shares of variable sources of renewable power generation …” — Jesse Jenkins, graduate researcher at the MIT Energy Initiative

The team explored technical constraints on flexible operations at nuclear power plants and introduced a new way to model how those challenges affect how power systems operate. “Flexible nuclear power operations are a ‘win-win-win,’ lowering power system operating costs, increasing revenues for nuclear plant owners and significantly reducing curtailment of renewable energy,” wrote the team in an Applied Energy article published online on April 24.

Audun Botterud, a principal energy systems engineer in Argonne’s Energy Systems division, is encouraged by how, for the first time, “this research evaluates and demonstrates the potential value of flexible nuclear operations in a realistic power system in the United States challenged by high variability in renewable-energy generation.”

The study helps to dispel long-held views that nuclear power plants must operate in “baseload” mode, producing power at maximum rated capacity whenever they are online. Nuclear plants can even respond dynamically to hourly electricity market prices and second-to-second frequency regulation needs, the team found. Power systems that include renewable energy must be more flexible to balance supply and demand at all times. Nuclear operators in France, Germany and other countries are familiar with this approach, but less so in the United States.

The researchers developed a mathematical representation of the physics-induced operational constraints arising from nuclear reactor dynamics and the fuel irradiation cycle in the Applied Energy article and a companion paper, published in Nuclear Technology. The interdisciplinary team then combined the new approach with power system simulation models to evaluate the overall cost of electricity generation, market prices and resulting revenues for power plants, assuming different levels of nuclear flexibility.

“Nuclear power plants are governed by a different set of principles compared to other generators, and our approach enables the representation of these relationships in the analysis of power systems and electricity markets,” said Francesco Ganda, the principal investigator of the project and a principal nuclear engineer in Argonne’s Nuclear Science and Engineering division.

By being flexible, plant operators can lower overall operating costs in the power system. For example, operators could generate less nuclear power whenever renewable energy is widely available. Nuclear plants could then exploit their spare capacity to sell valuable “operating reserves,” or the ability to quickly change power output to help grid operators rebalance supply and demand when unexpected events occur, such as power plant failures or errors in demand forecasts.

This flexibility could increase the profitability of nuclear plants by increasing revenues from electricity markets and reducing variable operating and maintenance costs. Overall, nuclear plant flexibility can also help integrate more wind and solar resources and reduce production of fossil fuel-fired energy and related carbon dioxide emissions.

Jesse Jenkins, graduate researcher at the MIT Energy Initiative, notes how the researchers’ modeling approach and study “gives us tools to further explore potential benefits of flexible nuclear operations to work in tandem with greater shares of variable sources of renewable power generation on the pathway towards low-carbon electricity supply.”



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NW sage

Nukes CAN be designed to operate with greater flexibility than current baseload designs BUT, there may be serious safety concerns (higher percentage of radioactive waste, poorer yield, etc) as well as the steam side efficiency where the turbine/generator runs more efficiently at a particular ‘sweet spot’
The safety studies and engineering is NOT trivial. And the increased costs must be known.
[I worked as an engineer at the Trojan Nuclear Plant until it was closed in 1993]

Leo Smith

The French throttle their nukes all the time.
The issues associated with doing it are well known and documented.
Of course economically and operationally the less one does it the better, and that means removing all unnecessary demand fluctuations from the grid by dismantling every now redundant wind and solar farm connected to it.
Storage is good however: examination pf electricity demand in most countries shows repeating diurnal fluctuations that can be met by a minimal amount of pumped storage or hydro dispatch.
Annual demand patterns can be met by scheduling refuelling and statutory maintenance towards the midsummer periods when demand is lowest (in temperate regions anyway).
However one should not add to the problem of load fluctuation by adding intermittent renewables.


That they can do it is not proof that it can be done efficiently or economically.


Your comments are all excellent, as is NW sage’s. One additional point to bear in mind regarding the French fleet, though, is that France took a Westinghouse PWR design and modified it somewhat for the extra wear and tear associated with load following. It takes so much more the just reactor design to accomplish this.
Consider the reactor coolant pumps, to take just one easy example. RCP’s in a baseload plant are designed to be turned on and run continuously at full power for 18 months at a time. This means that stresses associated with start-up only need to be engineered for a discrete number of cycles. (40 year design life divided by 18 month refueling cycle times some factor, like 2.5 or 5 or whatever…still a discrete number.) A system with load-following needs will have to take into account an unknown number of ramp ups and ramp downs, so will have to be designed to be significantly more robust than the baseload version. (Off the top of my head, I’m thinking probably primarily the stator/rotor package on the motor, maybe mechanical seals and motor bearings and the pump bearing…not sure about all of those, though.)
Anyway, I’m way too far down the rabbit hole here in these details, but my main point is, you’re spending extra time and resources and money and etc in order to get LESS out of the same system. When you’re doing it so you can bring in costly and inefficient power sources like renewables…well, it’s an unbounded absurdity!
I feel stupider now just having read this article!!!


Thanks Leo — good info. In the utility I worked for, the one nuke plant (Cook) was base-load all the time simply for economics, but that was many yrs ago….


The way “load following” is done in France is by anticipating, not following: a power profile a entered and the reactor is piloted to have the anti reactivity needed at a given time; rapid changes of reactivity can only be made with control bars, but partially inserted bar cause uneven use of the solid fuel, so water composition is altered to change anti reactivity in the whole reactor.


“[I worked as an engineer at the Trojan Nuclear Plant until it was closed in 1993]”
IOW, you’re utterly out of touch on the latest advances.

F. Leghorn

Really? I am not a nuclear engineer but I have a pretty good grasp of the latest technology. I suspect he knows much more than you or I.

Coach Springer

Not exactly an enlightened rebuttal. He knows, by an order of magnitude, more about why plants are operating the way they do than some cheerleader for “the latest advances.” The article has a lot on operating differently, but does not have anything significant on the subject of “the latest advances” – none of which would apply to domestic reactors built decades ago.


Wally, there’s hardly been a new nuke plant in a very long time. There have been advances in controls, but the coal plant I worked for changed over to modern digital PID controls not because of poor performance, but because of lack of replacement parts for the old pneumatic controls.


The cost of running a nuclear plant is almost independent of the amount of power that it generates.
Perhaps Sage or Retired Kit can provide actual numbers.
Reducing power output just means that you have to charge more for the power you do produce in order to cover costs. And that’s before you talk about any generation inefficiencies caused by not operating the plant in the manner in which it was designed to be operated.


Also, most reactors run at lower temperature to produce less power, so frequent power variations cause more thermal wear.

Leo Smith

balancing nuclear power with renewables is abut as sensible as putting sails on a nuclear submarine, and a moments reflection will reveal the truth of this statement and the sheer hypocrisy and doublethink that underlies this proposition.
Nuclear power is effectively zero carbon. Once you have built it – and that costs a lot – it costs very little to run. Uranium is cheap and you don’t need much of it.
Why would you throttle it back to make way for wind or solar?
You have added expensive renewables.
You have added instability and need to do more dispatch than is needful to meet demand. You have to meet not only demand fluctuations but renewable intermittency.
In short your costs are at least doubled, and there is no benefit whatsoever in terms of reduced carbon emissions. In fact carbon emissions associated with the manufacture of windmills and solar panels are increased.
To summarise:
There is nothing a fleet of dispatchable nuclear power plants cannot do that cannot be done worse and more expensively and with higher carbon emissions and more adverse environmental impact by adding intermittent renewable energy
Once you build nuclear, there is no reason whatsoever apart from naked rent seeking profit and virtue signalling to ever build a single solar panel or windmill ever again.
That this is being seriously suggested shows how far down the ‘renewables at any cost, not because they solve a problem, but because we will look stupid admitting the don’t work’ trail we have gone.
Ad it proves absolutely that renewables are not, and never have been, deployed to actually reduce carbon emissions.

michael hart

Agreed, Leo. I was trying to figure out the rationale behind “more nuclear means we can use more wind and solar”, and it was making my brain hurt.
Also, why would anyone want to run a power station at, say, 80% capacity if they could also sell 100% of what they can produce? Double brain hurt.

Randy Bork

As far as I’m concerned it doesn’t do MIT’s reputation any favors to have its name anywhere near this idiocy.

Joe Civis

I too was experiencing the “double brain hurt” on this.

Tom Halla

Yeah. Why bother messing around with “renewables”, which actually means unreliables? If one has the baseload nuclear, the wind and solar are just rent-seeking virtue signalling.

michael hart

It only makes sense in a crazy universe where electricity retailers are legally mandated to buy power from the unreliable sources, but not from nuclear or fossil fuels.
Unfortunately, I find that I do actually live in such a universe.

Leo Smith

precisely: And this is exactly why I voted the leave the European Union.The corruption inherent in framing alleged environmental legislation in terms of a renewable obligation instead of carbon emission reduction shows they never cared about solving the (nonexistent?) problem – merely generating a new profitable industry to strip money from consumers and put it in the pockets of corporates and bought politicians.
The depth of corruption and immoral cynicism inherent in their actions beggars belief. They have utterly failed to implement their side of the social contract – looking after the people whose work supports their affluence

michael hart

I voted the same way for similar reasons. Too long to derail this thread with, but successive UK governments have been no less green crazy than the EU itself. There is work to be done at home even if domestic politicians can no longer blame Brussels when the UK electorate get a bit ‘uppity’ about something they don’t like.

Perfect summation, Leo!

Perfect summation, Leo!
I agree.

NPPs (nuclear power plants) run most efficiently when running with a smoothed output, not a jagged one. I get the impression moderates, like Jessie Jenkins, care more for decarbonization, and keeping everyone in the Big Tent happy. Consensus. Now where have I heard that word before? So JJ is an ‘all-of-the-above’ guy, as will be most of the moderate Dems. Pro-WWS (wind, water, solar) and pro-nuke. Of course, NPPs can be ramped up and down. How well depends on the design. Ramping down means turning fission off. Yet you’re still, basically, using the same staff, plant, and amount of fuel. So your costs stay the same. Another example of WWS parasitic behaviour. You’ll not see a cost-benefit analysis argument here; unless it’s obvious – like comparing NPPs to giant electric batteries!

Leo Smith

Costs INCREASE slightly with dispatch. The extra wear and tear and the shortened life if the fuel rods are not compensated by the less fuel burned.
But this was all worked out years ago when nuclear was popular: Britain built Dinorwig – a pumped storage system – to cover short term demand peaks.
In general power and voltage stability is maintained in the very short term by the rotational inertia of all the turbines, then hydro and pumped storage act as very fast – less than a minute – sources of dispatchable power. Gas is the next best with stations being able to come up from cold in less than an hour and are extremely flexible.
Coal and nuclear tend to like to be mostly on, or off. Nevertheless Britain’s nuclear plant is often run below nameplate capacity to deal with maintenance issues – clogged coolant intakes or boiler safety issues.
What is undeniable is that intermittent renewable energy increase the problems of managing the grid.
It has no rotational inertia, and any response to simulate such has to be done in software that drives the inverters.
Its minimum capability – that is the peak to mean ratio – is so high and in the case of wind so unpredictable long term., that unless dramatic overcapacity is specified – which pushes costs through the roof – it cannot handle ‘times of low wind and no sun’. Ergo it CANNOT be operated alone, it always has to be in conjunction with a dispatchable energy STORE.
Optimally that is hydro – pumped or normal. Less optimally gas works OK. Coal and nuclear? disastrous, and in the case of nuclear completely pointless.
And yet this is the solution that lies behind the UKs energy policy. We are committed to Paris, and we are committed to an EU ‘renewable obligation’. We know that wont keep the lights on, so we will build nuclear baseload and balancing.
A political solution only.

Julian Flood

What he said.
It’s an indication of how muddled the debate has become that I read the OP without engaging commonsense, and I am someone who understands how daft the commitment to wind and solar is.
When will this madness end? And when it does, will anyone be held accountable?


Agree with this apart from the tag “renewable”. That is an inappropriate use of the word. The best description is run-whenever-you-like generation or a single word intermittents.
Using a term to describe run-whenever-you-like generators as “renewable” is highly misleading. You will have people believing that these monstrosities can somehow be replicated using the energy they produce – they cannot.

Shawn Marshall

Thanks for making the obviously sane statement that if you have the nukes all the other contraptions are capitally redundant – window dressing.


“There is nothing a fleet of dispatchable nuclear power plants cannot do that cannot be done worse and more expensively and with higher carbon emissions and more adverse environmental impact by adding intermittent renewable energy.”
Thank you, Leo.
Sorry, long time reader, first time posting a comment. I figured it was time, as I actually experienced a physical sigh of relief reading Leo’s post.

well, well
that is an interesting name ,
what in heaven’s name does it stand for?

Actually saw an ad in an early 50’s Life or Look magazine that proclaimed “Atomic power will make electricity to cheap to meter”
The biggest problem I have with nuclear power is;
Chernobyl- operator error
Three mile island- equipment failure
Japan- natural disaster
?????????- terriorism
All of the above are permanent.

Leo Smith

Chernobyl 50 dead. Long term biological effects seem minimal.
Three mile island No one died. No long term effects
Fukushima No one died. No long term effects.
In the case of 3MI and Fukushima the secondary containment did exactly what it was supposed to – contained a core meltdown with remarkably little radioactive release – well below any danger to life.
The bigger problem at Fukushima was caused by political restraints placed on nuclear power. With no clear political route towards spent fuel reprocessing and long term disposal, very large quantities of spent fuel rods were stored in more or less open ponds on site.
These represent a far greater hazard than the melted cores in the damaged reactors.
Terrorism is irrelevant. Nuclear power stations are not very dangerous even if loaded with ISIS people.
As far as build up of useful nuclear materials go, that is solved by making the reactors not produce anything useful for bombs, but useful for making more reactor fuel…
And anyway today’s terrorists cant even produce a chemical bomb reliably.
All of these are soluble problems.
Dealing with deliberately instilled irrational fear of nuclear power is the hard problem.

The potential for collapse of a flawed, safety-critical structural system is a shortcoming of nuclear power as a consequence could be massive carnage. It is argued that periodic nondestructive testing of these systems is effective in mitigating the damage but this argument is logically flawed.

“Terry Oldberg April 25, 2018 at 7:10 pm
The potential for collapse of a flawed…”

Bafflegab nonsense.

Agreed. Great book for the layman to understand how safe nuclear power is & the background to the present Malthusian madness & Darwinian daftness of present Western policies is Merchants of Despair, by Robert Zubrin, a PhD nuclear engineer with 9 patents to his name or pending.
His Case for Mars book is great also.
John Doran.


Indeed Leo. much of what you say could be achieved by use of modular molten salt reactors.
Operating at atmospheric pressure, with salts solidifying on failure, with process self regulation and stability and cost effective modular construction these are intrinsically safe and consume spent fuel rather than generating weapons grade material.
Why, on earth we are not investing in the development of of these is beyond comprehension.


Your comment reflects a complete lack of understanding of both the nature of the “safety-critical structural system” (more correctly called Safety Related) and the effectiveness of the “periodic nondestructive testing” (more correctly known as nondestructive examination, or NDE).


The potential for collapse is non-existent.
All you need to do is inspect it every few years.

Over 50 years of safe running, and John D. Smith is fearful?
Nothing, absolutely nothing, is permanent.
Leo’s already answered, but adding to the answers:
• Chernobyl: based on an outdated design, before they started building it. Russia’s rationale? It was cheap.
• Three mile Island: From the NRC;
“A combination of equipment malfunctions, design-related problems and worker errors led to TMI-2’s partial meltdown and very small off-site releases of radioactivity.”
Japan’s Fukushima;
“On March 11, 2011, a 9.0-magnitude earthquake struck Japan and was followed by a 45-foot tsunami, resulting in extensive damage to the nuclear power reactors at the Fukushima Dai-ichi facility.”
Lessons learned from both Three Mile Island and Fukushima have been incorporated into all existing USA nuclear reactors.
One does wonder why you fail to mention American military’s nuclear reactors that have been in operation since 1954. Currently, America employes 71 nuclear powered submarines, and 11 nuclear powered aircraft carriers in active duty.
N.B. “Since the first nuclear-powered submarine (USS Nautilus), the United States Navy has logged over 6,200 “reactor years” with no radiological accidents.”
Charcoal fires regularly kill people.
Wood fires regularly kill people.
Coal mining and fires kill people.
Natural gas has killed people,
Solar concentration facilities destroy wildlife,
Wind turbines destroy immense amounts of wildlife.
Yet, the safest, by far, energy generation source you have problems with. Problem(s) that appear to be entirely personal and nothing whatsoever to do with nuclear power or reality.

Plus, at Fukushima the main problem was poor siting of the backup generators to power the pumps. That is what led to the failure. If TEPCO had only remembered what was written on the plaques in the hills behind the reactor, then Fukushima would have only been a close call, not a major disaster.

Nigel S

Rolls Royce plans to commercialise military reactors. It seems a good idea.

Nigel S

This is a better link, sorry. The menu on the previous one takes you there too.

“Nigel S April 26, 2018 at 2:02 am
This is a better link, sorry. The menu on the previous one takes you there too.

I certainly wouldn’t bet against any engine Rolls Royce designs/manufactures.
Implementation, however… I keep having this image of Homer Simpson driving home with a piece of fuel rod stuck in his back hair.
Odds are, that R&R will design out any possibility of cretin access to nuclear material.


“Gold” has a great point about the Japanese location for the backup equipment.
After the levees failed during Katrina, my home town had classic examples of poor planning. Several hospitals lost backup power because generators were at ground level. Even homes that were on short piers and had no water in the living room lost their HVAC’s which were on concrete slabs. GASP! Nowadays you see HVAC units up on raised platforms to avoid water damage even with power still available.

“Gums April 26, 2018 at 7:19 am
“Gold” has a great point about the Japanese location for the backup equipment.
After the levees failed during Katrina, my home town had classic examples of poor planning. Several hospitals lost backup power because generators were at ground level. Even homes that were on short piers and had no water in the living room lost their HVAC’s which were on concrete slabs. GASP! Nowadays you see HVAC units up on raised platforms to avoid water damage even with power still available.

Aye, Gums!
I have some friends who were working at one of Tulane’s hospital buildings.
• Their first shock was that “maintenance” only kept a couple of gallons of diesel fuel on hand for the generators.
• Their second shock was when the levees failed and water covered the ground floor generator; eliminating any need for more fuel.
Then again, they were near parking garages that likely contained diesel cars; so it was drowning the generator that shut down the facility.
My old home was in Lakeview section flooded by the Bucktown canal levee failure.
The family that owned that house bulldozed it, which was a shame. I loved that house.

Hocus Locus

Actually saw an ad in an early 50’s Life or Look magazine that proclaimed “Atomic power will make electricity to cheap to meter”

The Lewis Strauss quote was taken up by Rod Adams in this interesting essay back in 2005 and then a followup essay in 2011… he was contacted by Strauss’ great-grandson who claims that Strauss had been referring to fusion not fission when he said that. In the time since fission has generated an awful lot of power, and practical fusion is only slightly less theoretical than it was then.
Over time Rod has chronicled the silly and naive attempts by the nuclear industry to be loved by environmentalists for its carbon neutrality. He has suggested — in approximate too-polite words — that grid stability and economy would be better served to never throttle nuclear plants back from full power or retire unless there is a compelling reason, and let the irreliable (my word) sources throttle back instead. Which would lay bare the scam of favoring unreliable sources over reliable ones.
I took no prisoners in my May 2016 Energy letter to then-candidate Trump and even took fusion to task for leading us on so.
Fission with liquid fuels is the answer, the one true path to survival of modern civilization. On either side we have wind/solar misleading as to its usefulness, and on the other fusion misleading on its likely unsustainably high cost of implementation. You need to ask, even if fusion containment is achieved, what is a plant likely to cost? Kirk Sorensen stated the problem with fusion (despite its promise) in one of his brilliant lectures. “Fusion is hard.”


“Fission with liquid fuels is the answer”
What was the question?


Others have dealt with the technology, let me address your claim of permanent.
There never was a need for an exclusion zone around TMI. People are already being allowed back into the exclusion zones around both CHernobyl and Fukushima. They could start living in both if the politicians would let them.

The head post photo is interesting. A field of solar panels next to the nuclear plant to keep the greenies/shareholders happy I imagine.
I would think that many green environmentalists/journalists/politicians have absolutely no idea just how many 10s of acres would be needed to be covered in solar panels to equal the output from this one nuclear plant…and then you would still need the nuke sitting there to take over at night or when the clouds show up (as they do).


Not to mention the utter destruction of the soil and it’s occupants underneath these carpet-like solar arrays.

This idea makes no sense at all.
But the mere thought of nuclear power enabling wind mills might just make Roger Sowell’s head explode…

dodgy geezer

…Nuclear power plants typically run either at full capacity or not at all….
Er… probably true for the 500 or so reactors which provide Base Load power for grids. Because of the low fuel cost, generating reactors are typically used for base power, and so they are designed to be most efficient in this mode.
However, NOT true for the 150 or so reactors which power boats – typically submarines. They need to be able to rapidly vary their power – so they are designed to do that.
There is no inherent reason why nuclear reactors can’t be throttleable – it’s just an issue of design…


Pretty much anything is doable, if you are willing to throw enough money at it.


“enable the use of more renewable energy”. Why even bother loading asynchronous, intermittent, costly energy sources into a stable grid? The best solution is a combination of nuclear, coal and gas based base load and load following plants.

Hocus Locus

Breeder reactors are “renewable” in the practical sense of the word, in that IF the fuel source is sufficiently abundant (like Thorium/U233) we can declare it practically unbounded. Leaving the pedantic definition in the gutter where it belongs.
I believe there is no possible balance between nuclear energy and so-called renewables at this point, survival of modern civilization is too dear. Weather-intermittent sources were a scam from the beginning. I propose a three step process,
1. Push solar/wind utility resources off a cliff. Defund and destroy. Let ’em rust.
2. While preserving nuclear and using fossil, get liquid fuel breeders online.
3. Revisit our ‘wind and solar’ HOBBY in the future with the grand surplus of energy.
Items 1&2 timeline next 15 years. Item 3, maybe never. There’s plenty more useful things to do. Human kind needs an energy source that lives in hardened buildings and puts out energy all the time. We’ve been scammed, people.


Breeder reactors died an appropriate death 40 years ago. The ONLY thing breeding addresses is fuel cost. Uranium is not rare nor expensive. Fuel cost is less than 20% of the cost of operating a nuclear reactor for electricity generation.
“It’s dead, Jim.”

Leo Smith

They died in the same way disc brakes and independent suspension died in the 1920s. They were better, but no one wanted to pay the price for ‘better’
They will revive when fuel costs rise.
All reactors breed to some extent.
There are 7 fast neutron breeders currently operating or operable, in Russia, China, India and Japan.
There are 16 designs being developed for when they are needed.
Currently is cheaper to burn new uranium. However when costs of reprocessing are taken into account it may not be in future.

Ian Macdonald

An utterly stupid response to a non-problem. It is far easier just to stop the turbines when there is too much renewable energy.
Let us not forget that Chernobyl was caused by reducing the output of a reactor running on old fuel The inherent danger is that the control rods may have to be withdrawn a long way to get it to restart, and the result may be a power excursion when it does. If the rods can’t be got back in quickly enough.. cue one 100-ton concrete lid flying in the air.


Thorium msr scalable, won’t melt down and don’t produce weapons grade byproducts

the plants have the technical ability to adjust to the changing demand for power and thus better accommodate sources of renewable energy such as wind or solar power“.
I think that needs a correction. Try: “the plants have the technical ability to adjust to the changing demand for power, so they could be far more effective than sources of renewable energy such as wind or solar power“.
If the powers that be (NPI) were sensible, they would simply remove any regulations or subsidies that favoured any power sources over others, and let the market sort it out – while customers reaped the benefits.

Leo Smith

The whole purpose of green legislation is to ensure that customers do not reap the benefits.
Just the moralising elites.
Surely you know this.
PS I am not joking.

Gene Walker

Why use expensive and unreliable “renewable” sources if nuclear steam turbine which provides the cleanest, most efficient, stable and least expensive power source is available?

It is certainly an inditement of the insane path that government has gone down in accepting the baseless CAGW / Global Warming meme, that anyone is even talking about balancing nuclear power with renewables. Renewables are as useful as a hole in the head, as when they don’t deliver, which is at least half the time, something else that could have been doing the job cheaper, has to step in. I liked Leo Smith’s comparison of putting sails on a nuclear submarine as it is totally accurate as a comparison.
Nuclear power is still suffering under the population’s sure belief that it will make them all glow in the dark.
Nuclear is expensive because of its safeguard requirements but is a lot more rational than irrelevant ‘renewables’. How about some high-efficiency coal plants, gas plants and other possibilities. Just don’t burden the poor with costly ‘renewables’ that intermittently drain their bank balances.

Some observations from an engineer that has been in the power business for many years.
Absolutely you can cycle nuclear units up and down. But is it economical is the question. Several things happen when you cycle a unit:
Overall efficiency decreases because at lower loads the turbine becomes less efficient. Also the pumps supplying reduced amounts of water typically are less efficient at lower load. Other equipment in the plant suffers from the same fate.
The life of the equipment is shortened. As loads cycle up and down the equipment expands and contracts in response to temperature differentials encountered when cycling the unit. This means that you are shortening the life of a very big capital investment and that is the reason that it is typically not done.
Many combined cycle units using natural gas that were originally designed to run during peak loads and then ramp down when the load reduces are not operating as base load due to the drop in natural gas prices. Those units are having difficulties because they were not designed to operate in that manner. Their equipment is not as robust since that were designed to run a lot less that base loaded nuclear and coal fired units.
In this strange era we are in a lot of the coal fired power plants that were originally designed to operate as base load are now being cycled. This has been hell on those units. A coal fired plant has so much more equipment needed to operate as compared to any other source of power they were designed a base load. Just cycling all the air quality control equipment on a coal fired power plant takes a lot of effort and creativity by the plant operators.
I will echo the thoughts of some above – Why replace dependable, cost effective, carbon neutral (if you consider that an issue), high capacity factor and reliable sources of power with expensive, unreliable, low capacity factor power sources. It may sound good but is it good for stable power generation in the world.
Someone mentioned above the installation of solar panels next to a nuclear plant to look green. Where I live in Pennsylvania a once peaking combined cycle power plant now operates almost 24/7. The plant owners
recently erected a huge natural gas storage tank near the plant so that fuel could be stored and then supplied to the plant in the event of natural gas shortage. They can also buy the natural gas on the spot market and store it in that tank. It was quite a tank to see erected. At the same time the erected solar panels in the field around the tank. The solar panels are easily visible from the main highway. So the owners are looking green.
One question that I have always pondered about solar panel power generating stations is what dictates the number of panels at the site or the surface area. At the site above there are maybe 5 acres covered with the panels. Ground level installation as opposed on roofs etc. panels. There must be 50 or more acres around this same area that are owned by the power company with very similar terrain and sunlight exposure as the 5 acres where the panels are installed. Why not the entire 55 acres if it is economical to generate power with the panels. To me it seems like that every square inch of area should be utilized to produce that great solar power.

are not operating above should be are NOW operating

I am not in favor of nuclear because of safety and other factors, i.e. waste, installation cost, etc
In terms of this proposal, if I understand it correctly, there would even be a lot more cooling to have to take place to stop the reaction on poor demand. Now here in South Africa we have the Koeberg nuclear station at maximum capacity and all the regular fish in the ocean around the station died because of the heat produced by the plant, i.e. I presume this heat comes from the cooling water from the plant.
now, to those believing that AGW is true, would more nuclear plants not produce a lot more GH gas, i.e. warm water = > water vapor?
Anyway, I also tried solar here on my own roof to run the office but I must say that I had nothing but trouble from it. Because there is some industry nearby, the solar panels get dirty quickly. So, you have to go on the roof to clean. I also had to replace batteries once. I had problems now with a broken regulator which has resulted in broken batteries, again. I think I am going to give up on it. It is just not worth it?
The solar geyser does work well, here, I am happy to report, but that works completely differently. It works like an inverted radiator.
I suspect the problem with the wind mills is also with the storage of the power (in batteries???)
I noticed in Belgium a plan to use the wind mills to pump water up to a lake or reservoir and here you can then flow the water down the river on demand for hydro electricity. That sounds like a good idea to me?

dodgy geezer

…I noticed in Belgium a plan to use the wind mills to pump water up to a lake or reservoir and here you can then flow the water down the river on demand for hydro electricity. That sounds like a good idea to me?…
Belgium, like its neighbour The Netherlands, is flat. That’s why they are called ‘The Low Couintries’. It has relatively few natural lakes, and none of any great size.

I think the idea was to create such a reservoir and the hydro plant that goes with it in the sea bed just off the coast of Belgium. I will check if I can find something on the internet.
The principle might work better for us [in Africa/ USA] where we have a lot of hydro and you would use the wind down stream pumping the water back up again. Sort of like, perpetual energy from the same water!
One might have to check if there is enough wind down there…

Leo Smith

I really would like more than just an assertion by someone who clearly believes all the negative propaganda about nuclear, that Koeberg killed all the fish…
I read with dismay how the renewable lobby is organising itself to pull the wool over South African eyes, and have succeeded in stopping Eskom’s plans for a new reactor. The scene is set for ‘state capture’ of energy and unreliable nonsense being foisted on the public as the New Green Clothes of the Eco-Emperor.
As far as waste heat goes, simple maths and research will show that an estimated 150,000 TWh per year (wiki) of energy, all of which ends up as heat, is consumed by the human race. Less than 2% is ‘renewable’.
That equates to about 17 TW average.
spread out over the 510million sq km of the earth,
I make that 0.03W/sq m excess heat.[Please people do the same sum and tell me I got it right?]
Compared with the 4W/sq m that the IPCC adduces to CO2…
In short our direct effect on actual climate (as opposed to urban weather stations) is two orders of magnitude less than that supposed to be due to carbon dioxide.
To put that into context: total solar irradiance – TSI is…at least …[wiki]

“The most probable value of TSI representative of solar minimum is 1360.8 ± 0.5 W/m2, lower than the earlier accepted value of 1365.4 ± 1.3 W/m2, established in the 1990s. The new value came from SORCE/TIM and radiometric laboratory tests.”

So in the context of 1360 watts per square meter, even the IPCC can’t do much better than 4W/sq m for CO2 effects and direct heating effect of burning fossil and nuclear fuel is 0.03W/sq m


Nuclear is by far the safest form of power generation.
There is no waste storage problem, there is a political problem. Nuclear waste can be reprocessed, and in many countries is being reprocessed. It’s the politicians who are preventing that problem from being solved.
Installation costs are so high because the environmentalists and other luddites keep throwing up legal obstacles that drive up construction costs.

Leo, & Mark &
they bury the nuclear waste from Koeberg here somewhere in the desert halfway between Cape Town and Kimberley.
On my approach to visit the site I was met by numerous stay away signs warning me of the danger of nuclear radiation. I suppose that was to give me the feeling that all is ‘OK’ with the nuclear waste and all that?


henryp, you aren’t big on actually reading what other people say.
The only reason why they bury the waste is because the politicians won’t permit reprocessing.
Once they reprocess, there is nothing left that needs burying.


Coal and natural gas power plants also have cooling ponds.

with gas you only have to cut off the fuel?
gas is best
[at the moment]

Leo Smith

No, You have cooling towers like as not


The amount of cooling that a nuclear plant needs goes down rapidly as soon as you shut down the reaction.
Regardless, so what if turning off a fossil fuel plant means you don’t need any more cooling. You also aren’t getting any power.

You are missing two important limits to pump storage.
The first, the most important is the old real estate rule of “Location, Location,Location.”
There are very, very few locations where the huge areas required for the upper and lower lakes (lower could be a river – but then are you going to pump the river backwards to refill the storage lake?), room and geology for the dam(s) required, reliable water supplies NOT already committed to other uses and other users.
Best are the large man-made (money,money, money) storage reservoirs below the Falls above the niagara river. The water from Lake Eire flows downhill from Lake Eire through huge tunnels to the man-made lakes above the power plants, then refills those lakes which can drain through the same power plant as is using the Niagara river water during the night when the falls are “turned off” and near-100% diverted for power generation for NYC and environs.
But there are few Lake Eire-Niagara Falls combinations worldwide. And those man-made reservoirs caused HUGE disruptions and protests about one part of one end flooding an Indian burial ground. Can’t do them any more.
But, other problems abound. Biggest is energy conversion efficiency. Your goal, remember, is to take grid electric power at 450,000 volts when it is generated at lower need times – store it – and get grid electric power back at 450,000 volts when you want it. (When electric power is needed at higher rates.)
Pump efficiencies are 70-80%, turbine efficiencies are a little higher at 95-85%. Motor efficiencies at very high voltages are pretty good – 0.85 is typical. Transformer efficiency to go from a motor’s 4180 or 6000 volts to and from the grid’s 450,000 volts are very good: 96-98% of the original energy is converted to the other voltage. Water flow resistance is 4-6% add another losses. Convertable, dual-way turbine-pumps are lower efficiency than pure water pumps or pure hydropower turbines because their blades have to be both pump and turbine – they can’t be optimized for only pumping or only generating power.
But all of these losses are two-way.
Grid voltage -to transformer- to motor voltage. (and all control and auxilairy needs like lube oil pumps and filters, etc.)
Motor voltage-to rotation energy
Rotation energy to pump vane energy
Pump vane to water pressure at low elevation
High pressure static water (at low elevation) – minus flow losses – to potential energy at high elevation.
Evaporative losses while waiting. (Not large, but you need to include them as well.)
Static water at high elevation to flowing water ( with frictional losses again) at low elevation at higher pressure
High pressure water to turbine vanes rotation
Turbine vane rotation to generator rotor rotation
Generator rotation to generator electrical voltage
Generator voltage to transformer to grid voltage.

Leo Smith

To summarise: Dinorwig in the UK achieves 75% turn-round efficiency…that is fairly typical for pumped storage.

that is some explanation
sorry, it is a bit above my head, I am not an engineer.
‘(lower could be a river – but then are you going to pump the river backwards to refill the storage lake?), ‘
but yes, that was my idea, in places where river flow is not so great, or going down due to drought, is to use the wind to pump the water downstream back to refill the storage lake.

I worked at nuclear plants on Lake Michigan and our cooling water discharge attracted fish — large Salmon and other varieties typical of the area. Popular fishing areas.

Yes. I am sure warmer water will attract more types of fish. But same rule apparently does not apply to salt water….


The proposal is to have a mix of nuclear and solar/wind. And because the solar/wind is intermittent, you throttle the nuclear up and down to compensate. Also since at times the solar/wind will be zero, you need enough nuclear to carry the full load.
So, you spend the money to build, operate and maintain enough nuclear to carry the full load AND you also spend the money to build, operate and maintain some level of solar/wind. And somehow this is economical? Really? Next thing you will try and convince me that it is cheaper to buy both an internal combustion car AND an electric car when I only need one vehicle.

Leo Smith

Ah, that has happened already.
You have an electric car for going to London in, where the damned things are tax and congestion charge free, and a diesel to go anywhere else, because it has the range and convenience.
As a low mileage pensioner, a major component of my travel cost is car TAX. This tax is there irrespective of whether or not the vehicle turns a wheel in anger, as is the insurance. It would make sense for me to use an electric car for 95% of my journeys BUT I would still need a diesel car to do any distances.
Unfortunately the extra tax and insurance means I run the diesel car only.

Leo Smith

Not just dodgy, utterly insane. The cost of pumped storage plus renewables is way higher than nuclear.
And the ecological footprint is massive..


Pump-storage has been around for a long time, mostly to avoid having to throttle-back nuclear plants when demand is low. Like all storage systems it adds cost and the variability of renewables means that several days of power have to be stored; rather than the few hours required to smooth out demand.
The Belgian proposal seems particularly daft because:
1. The height difference between the high and low reservoirs will be small and so a large volume will have to be transferred to store a significant amount of energy.
2. The water being pumped is sea water, full of salt (a corrosive) and assorted other things including sea-life. So it will be mincing fish to go with the birds minced to generate the power.

Good points.
I still think using wind to pump water to a higher reservoir from where hydro electricity can be produced on demand, is a good idea?


It can work, whether it would ever be economical is another question.


This idea was ditched years ago – way too expensive.

but it seems the original idea is possible: use wind to pump the water to high and use the [extra] water for hydro energy

Leo Smith

When I went round the precursor to Dinorwig in the 60s, they explained that having a pumped storage station saved one nuclear power station having to be built .
Specifically the UK shows a winter demand peak at around 6pm when everybody gets home, turns on the lights puts a kettle on and switches on the telly to watch their favourite soap opera, and then cooks ‘tea’.
This is several GW over the daily norm.
At the time contemplating an ‘all nuclear ‘ generation strategy the engineers calculated that if they could supply 3GW of short term capacity to cover that peak, they could save the cost of two nuclear power stations.
In the evənt gas was discovered in the North sea, and capital intensive plant like nuclear became infeasible due to massive inflation and high interest rates.
CCGT is cheap to build – far cheaper than nuclear – and was reasonably efficient to ramp up once a day to cover peak demand.
In the UK coal is no longer economic to mine, gas is now running out and until the controversy around fracking is resolved, likely to stay that way, so we are again contemplating nuclear, as quietly as possible.


Finally, a perfect solution. Build thorium reactors, make them “variable” with renewables (other than hydro), then set renewables to zero, then recycle the renewable installations back into thorium reactors. And save hundreds of thousands of birds, bats and make the countryside green again.


“Thorium reactor” is nonsense. It’s not fissile.
[? .mod]


“Thorium reactor” is nonsense. It’s not fissile.

Usually, the term refers to the fuel around the core (thorium) which – over a period of time and neutron bombardment and subsequent radioactive – transforms to fertile U233, which then absorbs neutrons and splits up into radioactive energy, additional neutrons and kinetic energy and high-speed daughter products. The thorium itself is merely a target (and thus a “future fuel”) for the initial neutrons from prior fission activity.

Leo Smith

It is fertile though.
The fissile part is U232 formed by bombarding the thorium with neutrons from the U232 fission.
It may need a plutonium or uranium 235 ‘starter’ but once running it is self sustaining.


Not so, Mr. Cook.
The U.S. found at Savannah River and Shippingport that thorium targets did undergo some transformation to U-233, but NONE of it participated in subsequent fission.
U-233 was obtained by separations of the thorium targets OUTSIDE the reactor. None of that U-233 was ever used anywhere.
Long term – hundreds of years out – breeding thorium to replace uranium may make sense. It doesn’t now.
MSRs could change that, as, theoretically, a U-233 atom in the slurry should behave as other uranium atom. MSRs bring a host of other problems, though, and their use is not certain to happen.


Mr. mod, “thorium reactor” is fanboy marketing talk. We have uranium or plutonium fission reactors. The idea is to breed thorium into uranium to participate in the nuclear reaction. Calling them “thorium reactors” is nonsense.


No, Mr. Smith. The objective is to get U-233 from thorium.
U-232 is an ultra nasty gamma emitter. Savannah River got about 8 grams of it while making 610 kilos of U-233 from thorium.
By creation of U-232 in MSRs is an unknown. Potentially, it could poison the whole damn thing.

Leo Smith

@gamecock. I beg your pardon – you are completely right
The fertile Thorium 232 absorbs a neutron to become FISSILE Uranium 233, which is what sustains the chain reaction and creates more neutrons..
Or the U233 may absorb more neutrons to become U235…again perfectly fissile. Or that itself may transmute with more neutrons into plutonium 239 and upwards.
The point about a fast neutron breeder is that you are taking relatively useless long lived radioisotopes and turning them into good reactor fuel.
U238 and T232 are both fertile and are both long lived radioactive elements. Breeding gets rid of them. The greens ought to be overjoyed at the nuclear power industry removing ‘dangerous natural radiation’ from the earth and turning it into ‘green energy’

Coach Springer

I have a family member in that industry. No question the industry has bought into zero carbon and renewables due to one of their characteristics and political expediency. Co-existing with renewables is like co-existing with a parasite that will either kill you or render you a slave in need of life support. All for zero carbon that would not naturally be anything more than a tertiary consideration of a utility.
I am quite sure that nuke operators have looked at these strategies for co-existing themselves. They are aware of how France ( and Japan and Germany used to) operates. They are desperate for economic viability. They are ready to throw natural gas and coal under the bus to do it, while knowing that the politically viable renewables are the ones killing them. That ultimately makes them an enemy of plentiful, cheap and reliable power.

Jeff Id

It’s easy to balance working technology successfully with non-working technology.
100% working 0% non-working
Power fluctuation problem solved.

Bruce Cobb

Nuclear energy as backup for renewables? What are they smoking? That is some weapons-grade Stupid right there. When you invest $billions in a power plant, you want it working as much as possible to help recoup that investment.

This seems to be highly exaggerated. Nuclear plants need to operate at a high capacity as their per unit prices are almost linear with capacity, due to the fact that the fuel in a nuclear plant is such a small cost component – typicallty 3/4th of a cent per kWhr. You cannot destaff a nuclear plant while it is operating, regardless of its current output, therefore the cost savings by reducing output would appear to be minimal. Accepting renewable energy in preference to nuclear power, reduces the nuclear capacity and can reduce the income for a nuclear plant to such an extent that it loses money, something which has occurred frequently in the past. It may be true that a nuclear plant can physically be operated as a variable generator, but the economics says they cannot be operated in that fashion. BUT, all this refers to conventional nuclear reactors, and I argue that conventional reactors are shortly being replaced by the MUCH cheaper and inherently safe
small moduar molten salt reactors, which CAN operate as load followers (vary their ouput quickly) .


Any type of power plant can respond dynamically.
Whether they can do so efficiently and economically is an entirely different question.


Where in reality is it wise to use TWO very expensive power sources when ONE will do. Only a fool does that.

I want to connect my hamster wheel to a battery, and figure out how much power I can use intermittently from my regular power company to complement my little hamster’s input into the whole system, so that I can use the same amount of power, but split between my furry little friend and my mean ol’ fossil-fuel guzzling beast.


Of course making nuclear better, safer and adaptable to changing demand will make absolutely no difference to the greenies. They hate nuclear energy as much as they hate fossil fuels and will fight nuclear power every step of the way. It is the clearest demonstration of the gross hypocrisy going. Remember Yucca Flats storage? It may still be in litigation. I quit tracking it all when some left coast judge it was before ruled that the government had to come up with signs that lasted more than the half life of the waste stored there.


Greenies in particular and leftists in general hate anything that they don’t understand.
Which is pretty much everything.


Sadly they believe they know it all and the rest of us are the ignorant ones. I once qualified legally as an expert on several subjects. Yet regularly I had environmentalists and technocrats tell me I was not just wrong but flat wrong, lying and trying to spread propaganda paid for by someone they never defined. When I produced journal articles, data, etc they just got very angry.

I suspect nuclear flexibility is not going to be as easy as this author is anticipating. I think nuclear and renewables are in conflict and nuclear is the better choice. A while back, I ran into his disturbing piece:

A Germany nuclear plant was damaged because its operators increased and decreased its output to respond to energy grid fluctuations. The incident supports the theory that nuclear and renewable energy generation are incompatible. EURACTIV’s partner Der Tagesspiegel reports.


The real question that articles like this never ask nor answer is “Why would you force a large generator that operates at a 97% capacity factor to vary its output to “generation-follow” a source with a 20% capacity factor?”
If you use nuclear generation, whatever do you need wind or solar for?

Joel Snider

Truth, I’d be all for nuclear energy. The marching brooms won’t ever let it happen.

Gary Pearse

Oh no! Don’t design it 8n to new nuke.


April 26, 2018 at 5:30 am
“Why, on earth we are not investing in the development of of these is beyond comprehension.”
Because it’s a bad idea, in spite of what the book you read told you.

Retired Kit P

Let me explain these studies. There is a welfare system for our national labs and university systems. We need to keep them busy when there is no cold war work to do. So do not worry too much about it
All US commercial and naval LWR are designed to load follow (change power output). It is an operational necessity even if we rarely use it. It is part of safety analysis models. We validate models during startup testing. It is no big deal.
If fact all steam plants can load follow. That how we do it if hydro is not can not be used.

Leo Smith

Even at the level of simply dumping excess heat into a vast pond of water, nuclear can be throttled back.
But e.g. smelting aluminium with the surplus is also a good plan.

Retired Kit P

In the US, FERC now requires new large power plants to keep running even if there is a loss of transmission capability. This way power can be restored faster when the transmission problem is resolved.
None of the plants I worked at had a large enough steam dump capacity to handle a complete loss of offsite power.
The EPR is designed with 100% steam dump capability followed by a controlled down power to house loads. This a much less severe thermal transient than a scram to hot standby.
I did the calculation for the US design (60 hz). Since the US grid is much more stable than Europe, we have 35 million less transients associated with maintaining grid voltage and frequency.


And BTW, there is no such thing as “renewables”.
It’s spelled “weather dependent production unit”.


I truly wish that well reasoned sites like this one would stop giving credence to the “,believers” by using the term “renewable energy” . There is no such thing. For instance: How does humanity “renew” the wind? The Sun?


Here is how consumption tracking is followed (instant, hour, day, week, etc.) at the production level, with nuclear and hydro operating mostly, in France. Text is in French but all the different settings and actions on how to pilot nuclear reactors, plants, and the whole network is described:
In 2 words: nuclear has enough built-in flexibility to sustain any kind of network demand at any time-scale provided the nuclear plants are rather homogeneously located.

My Senior Reactor Operator training is 60 years old, so I’m more than a little rusty; however, one problem with cycling reactors is when you reduce power, fission products that we used to call “poisons” built up in the reactor. The isotope that has the biggest affect when power is reduced is Xe-135. ( As soon as the reactor power is reduced or the reactor is tripped, Xe-135 increases for about 15 hours. When you want to increase power again, there has to be sufficient reactivity in the reactor to burn out the Xe-135 and achieve/maintain criticality or the desired power level. If the reactor cannot be immediately restarted after a trip, it takes about 30 hours for the Xe-135 to decay sufficiently to enable restart. If the power is being varied, each increase has to use some of the reactor power to “burn out” the Xe-135. Anyway, there’s a built-in nuclear inertia with reactors that complicates using them for load following. ‘Never read anything on how this might affect plant efficiency.

Chester Energy and Policy

Thanks for this review of the study. Nuclear and renewable can, and should, work together to provide the best carbon-neutral energy sources for the country and the world. While the industries are often siloed, hopefully this can signal the beginning of them working together, both technologically and in terms of the politicking that (unfortunately) is needed for real change in the energy space. Obviously a carbon tax would benefit both industries, and their collective power might be enough to take on the fossil industries of the world.

DC Cowboy

The problem is that, when viewed from a cost/benefit analysis, nuclear alone can accomplish that goal. Solar is no more than a ‘niche’ need filler.