Balancing nuclear and renewable energy

April 25, 2018 by Cathy Milostan, Argonne National Laboratory
Power plants that balance nuclear and renewable energy could increase revenues from electricity markets and reduce variable operating and maintenance costs, according to Argonne scientists. Credit: Vaclav Volrab and 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 generated in a more flexible manner, the researchers say, the plants could lower electricity costs for consumers, enable the use of more , improve the economics of nuclear and help reduce greenhouse gas emissions.

The team explored technical constraints on flexible operations at 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 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."

Explore further: Nuclear generation in April at lowest monthly level since April 2014, says EIA

More information: J.D. Jenkins et al, The benefits of nuclear flexibility in power system operations with renewable energy, Applied Energy (2018). DOI: 10.1016/j.apenergy.2018.03.002

R. Ponciroli et al. Profitability Evaluation of Load-Following Nuclear Units with Physics-Induced Operational Constraints, Nuclear Technology (2017). DOI: 10.1080/00295450.2017.1388668

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4.1 / 5 (10) Apr 25, 2018
Unlike coal and gas that need to be "greenwashed" by intermittent renewables, carbon-free nuclear power is the most ecologically friendly per unit of energy produced as it causes little or no impact on natural landscapes, wildlife habitats, birds and bats and other endangered species.
In practice, fossil-addicted parasites (useless placebos) like wind and solar are completely unnecessary except to please the Eco-nuts and to make the electricity bills costlier, e.g. Germany, Denmark, South Australia, California, Minnesota, etc.
3.4 / 5 (5) Apr 25, 2018
Throttleable nuclear was not thought of when I went to engineering school at Sac State (now California State University at Sacramento), graduating in 1976. Then we had five nuclear plants providing the base load, with the variable load balancing provided by our hydroelectric dam systems from the California Water Project. Nearest to me was Rancho Seco, a giant brought down by the Soviets and ChiComs in alliance with Iranian dissidents who incited useful fools in our 'hippeee movement. Most of the hippees were really draft dodgers who would have latched on to any plan to not be in the army and have to fight....or...maybe ...get.......wooonded!..or worse.
Rancho Seco had a nice swimming lake, one of my favorites. AS yet, this 10 year air force vet does not glow in the dark at the ripe young age of 72.

Many other factors brought down our nuke plants, one being tendancy to push materials science to the hairy edgy of failures in for example, turbine blade design.
3 / 5 (4) Apr 25, 2018
There still is a niche for solar photovoltaic panel plants. These were not even thought of when I went to engineering school. Then, solar collectors were heavy, delicate with lots of glass panel and lead solder and copper pipe and plating, all painted black. These were for rooftop use, and required complex electrohydro control systems and toxic antifreeze solutions to safeguard against freezing in cold conditions.

Now....photoelectric panels come in 200 watt sizes and are light and easy to maintain. All one has to do is ...'dust' them. Feather dusters do nicely. Will install them on my ranch and get rid of $500/mo. electric 'gouge'. This gouge is penalty we Cali residents pay for listening to the damn hippies and their commie agent agitators. As a student I personally witnessed them constantly in the background of 'student demonstrations'. These stooges of enemy agents destroyed California's energy independence...IN and out of court when they returned as lawyers.
4 / 5 (4) Apr 26, 2018
You've drunk the kool-aid.

The reason you're being gouged is regulatory capture. The California Public Utilities Commission is staffed entirely by past and future lobbyists and executives of Pacific Gas & Electric. And some from SoCal Edison. They rubber-stamp every rate increase the utilities want.

In addition, the laws guarantee the utilities at least 10% profit (after all expenses, no matter how excessive and wasteful) on every investment (no matter how foolish or duplicative). Not break-even, 10% profit, free and clear.

So they keep building power plants that no one needs, putting other companies out of business. They keep tripling the rates for standby power and transmission that they charge everyone who uses none of their energy, to put privately-owned co-gen plants out of business. (Not an exaggeration, I work in this sector, they did it to my institution. PG&E is charging us as much for no power as they would if we took all the power from them.)
4 / 5 (4) Apr 26, 2018
As for nuclear, the second-to-last plant in CA got closed down a couple years ago, not because of the hippies, but because of rank incompetence and mismanagement by the utility company. They overhauled the plant so badly it had to be decommissioned. The cost of the overhaul and decommissioning was in the billions; fixing it would have cost twice as much.

The utility got to pass all of those costs on to the ratepayers. Their shareholders lost not one red cent.

Similarly, when PG&E blew up a neighborhood in San Bruno ten years ago, they said they would start investing in gas pipeline safety. So they got a huge increase in their rates to pay for that. Never mind that they had already been charging a fee for pipeline safety for decades. Isn't that fraud, and wouldn't killing people by negligence be manslaughter? No one was prosecuted. Then, on top of all that, the CPUC let them add the clean-up and settlement costs (over $1 billion) to the rates, too.
4 / 5 (4) Apr 26, 2018
You and I and everyone we know are the victims of corporate corruption of public commissions and legislative processes. Incompetence and greed and fraud caused the demise of your beloved nuclear power plants. No hippies or the lawyers they turned into had any real impact on any of it.

But you've swallowed the propaganda, living behind the smokescreen of their public relations machinery. Congratulations.
2.3 / 5 (3) Apr 26, 2018
"...the researchers say, the plants could lower electricity costs for consumers,..."

Made me laugh outloud!

Yep, just what we all need. More centralized, militarized security ridden, self-selected elite domination of energy production.
3 / 5 (2) Apr 26, 2018
I don't see why it would be difficult to run a nuclear plant at less than 100%. If you're generating steam that goes to turbines, then all you need to do is have multiple turbines.

Say you have 5 turbines, and you want to run at 80% capacity. Spin down one turbine, blow off that steam (i.e., do not adjust the nuclear reactor, keep producing all the steam), and run the other 4 turbines at full capacity.

What is the problem? Is it that they designed all the plants with one giant turbine?
5 / 5 (2) Apr 26, 2018
Not only it's difficult but it may be also very dangerous: this is just the regime which launched the Chernobyl reactor into a stratosphere

What set Chernobyl up was when they cut the generators off from the grid to run the reactor in a fault mode, and then it failed to fail safe.

Most nuclear powerplants are designed to throttle safely and quickly. The reason they don't is because they get more money by selling regardless of the selling price, since there is practically no fuel costs. Even if the price is less than the average cost of operation, it's still cuts losses to keep the turbines running than not selling anything.

The idea that nuclear powerplants could make more money by being more flexible is dependent on the fact that by letting more renewables on the grid, they will increase the swing in prices, so the nuclear operators get paid more to patch the gaps.
5 / 5 (3) Apr 27, 2018
If conditions are right, power can be changed at a rate of 6 to 10 MW/second and even this rate is not limited by the core but by the balance of the plant. Some fancy reactors in use today can run at %60-%100 but they still take hours to adjust to a new throttle setting.

The reactors are designed to allow for load following typically in the range of 50-100% capacity. It's been a design requirement for many generations of powerplants.

It doesn't take a fancy resign, nor does it take hours to settle down. Going below 50% output, things slow down because of the residual delayed decay that keeps the heat output up. You can go from 100% to 50% heat output in minutes, from 50% to 10% in hours, and from 10% to 1% in days.
not rated yet Apr 27, 2018
how does throttle effect efficiency? I thought a reactor need to run at highest temperature for max efficiency...
3.3 / 5 (3) Apr 27, 2018
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

This says it all.

Currently the cost of power from nuclear power plants is quadrupel (!) that of solar and double that of wind (and 1.5 times that of coal) per kWh. I doubt that flexible nuclear can compete on any level. The only thing it might be able to do is lower the cost of the most costly electricity source (i.e. nuclear itself)...but that's like lowering pollution by investing in slightly cleaner ICE cars when electric cars are readily available.
5 / 5 (2) Apr 27, 2018
"Non-baseload Operation in Nuclear Power Plants: Load Following and Frequency Control Modes of Flexible Operation"
3.7 / 5 (3) Apr 27, 2018
Currently the cost ... is quadrupel (!) that of solar and double that of wind...
Interesting that "cheaper" wind/solar are making the electricity bills costlier everywhere.
"...the energy in the wind is of low quality. Turning it into high quality, reliable energy for the consumer is still very expensive indeed." - Apr 2018
"One big reason seems to be their inherently unreliable nature, which requires expensive additions to the electrical grid in the form of natural gas plants, hydro-electric dams, batteries, or some other form of stand-by power."
3.7 / 5 (3) Apr 27, 2018
Currently the cost ... is quadrupel (!) that of solar and double that of wind...
Wind/solar is "too cheap to meter" making electricity "too expensive to meter", e.g. Germany, Denmark, South Australia, California, Minnesota, etc
" shows that wind energy in Ontario is 207% more expensive than nuclear while solar is 666% more"
"Minnesota is blowing billions on wind power ... the result is HIGHER electricity rates and dubious CO2 reductions"
"If Solar And Wind Are So Cheap, Why Are They Making Electricity So Expensive?"
not rated yet Apr 27, 2018
Spin down one turbine, blow off that steam

Ouch... Steam (and whole the electricity generator in more figurative sense) are important coolers of reactor and dissipators of its permanent energy flux. You just cannot blow off the steam in a secondary circuit without risk of blowing the steam in a primary circuit, ...

I don't think you understood me. Steam trains use boilers and they blow off extra steam when needed without blowing up.

Keep all the cooling water on the reactor, keep the steam pressure up, don't change that end of the system at all (caveat below).

You have multiple steam valves on the other end, each going to a turbine. For the turbine you don't want running, divert that steam away from the blades. Same steam path and pressure, just no electricity generated.

Voila, turbine is not running, steam pressure is unchanged in the system, reactor is unaffected.

Caveat: if you want to drop more than 10-20%, adjust the reactor power.
not rated yet Apr 27, 2018
As you all noted, the nuclear fuel cost is very low. It doesn't matter if you burn up more of it to produce steam you are not using. At least, it has very little effect on the ultimate cost of the electricity produced. But the water/steam is crucial to cooling and safety, so pour it on.

To be extra clear, I'm specifically saying NOT to throttle or adjust the reactor end of things. That's not needed to reduce electricity output, and it is inefficient and potentially unsafe.

And you should not adjust the cooling systems or steam production. That takes time and is unsafe.

The thing that is both safe and instantaneous is what you do with the steam at the output valve. You can just throw it away, if you don't need electricity at that moment. No safety or operational impact.

Put 100 small turbines at the output, and you can adjust your electricity generation to your heart's content, and you have much more failure tolerance. Costs more? Not much, when the plant costs billions.
Da Schneib
1 / 5 (1) Apr 27, 2018
@dnat, I agree with your evaluation. The time when the extra steam is released from the outer loop (the non-radioactive loop) and not used to generate electricity is electrical system buffer time for the reduction of the nuclear reaction, which is not instant, particularly not in terms of heat which is retained in the core and must be released somehow to prevent reactor damage. Once the nuclear reactor reduction has taken effect and the heat dissipated it is no longer an issue and the steam can be turned off at the unneeded turbine(s).
5 / 5 (2) Apr 28, 2018
You cannot throttle Nuclear
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

This whole article is about eliminating nuclear power "enable the use of more renewable energy" by subtle manipulation of discussing throttling, it is disguising the real agenda of eliminating nuclear in favour of renewables. Because you cannot throttle nuclear, the objective is clear; eliminate nuclear!
3.7 / 5 (3) Apr 28, 2018
"enable the use of more renewable energy"
Intermittent renewables are just to provide "greenwashing" for fossil-fueled backup plants, specifically flexible gas-fired plants, in order to eliminate carbon-free nuclear energy(the only scalable way to stop Climate Change).
Eliminate fossil fuels, and wind and solar die.

"No sun? ☀️ No wind? No problem, natural gas has it covered. See why #natgas is a great partner for renewable power sources."
"Shell says renewables won't replace oil any time soon"
"Shell says fossil fuels are here to stay as renewable electricity not powerful enough for industry"
3 / 5 (2) Apr 28, 2018
Been a lot of lying about nuclear plant expense, or should it be said 'dis-information' or the latest gibberish...'fake news' ala ignoramus liar n thief in cheeep! Small costs can be killers in utility cost estimation given competition and focus on quarterly bottom lines. 800 pound gorilla in the room then becomes the legal burden and political burden of fighting entrenched nuclear opponents...hippies and commie dupes that grew up, went to work ahead of patriots that actually fought for this country and proceeded to beat us from the inside, where they remain. I know there are trolls on here that will do their job for Uncle Vlad and vote 'one' and do it often. Russians only close reactors when they blow up. Sell the oil to the suckers while they work on breeder cycles that make mockery of so called limited nuke fuel supply. Do not even mention thorium cycle that produces little rad and is cheaper yet. Look at India for common sense. They not dumb. They makin' mo' reactors
4 / 5 (1) Apr 28, 2018
We in this nation have over 150,000 square miles of 'deserts' in the United States. We have much more land that is 'not desert' but not in much demand either. The point is part of a question an electrician answered as to how much area it would take for a solar farm operating at 100% Effic. to supply our total electrical demand. The electrico said: about 1000 square miles. Given that panels struggle at the fringe of tech to make 42% Eff, it is better to nick that up a factor of four for a factor of safety that we engineers like in order to be comfortable. That author's comic book thinking assumed the whole plant in one place which in the land of terrorist targets that we are now is insanity on the hoof. Perspective... 30 miles in a square shape is 900 mi^2!...less than a Michigan 'township'! So just four or five townships. Best is small areas that together equal this area but distributed all over the nation. Churchill's unsinkable armada of power. Just dust them!
2 / 5 (1) Apr 28, 2018
We can build this equivalent four townships' area worth (see previous above post) of power in less than a few years in thousands of small distributed solar farms of 300 acres (average Michigan corn farm) or so, with a couple of acres of battery backed storage buildings. Sun charge the batteries by day and batteries provide all the power at regulated voltage thru large inverter systems fo provide continuity of power at all times, cloudy at night, peak power, low lite, or not! The trick will be to have enough batteries. If lead, that can be recycled when they wear out. If NiMH, then pay attention to temperature and load. None of this is beyond what we can do. For vehicle fuel, use hydrogen for fuel cells. New nanostructured fuel cells being 'discovered' all the time. Pick One! Or many so not single sourced for anything. Same for panels. Go around obstructionists with national defense orders to stop snail darters from impoverishing Americans. We GOT da grid NOW! USE it!!
1 / 5 (1) Apr 29, 2018
Our petro/scientific establishment does not like cold fusion, inasmuch as ordinary people may be able to make it. One of the leading proponents was a 'shunned' scientist named Rusi Talyarkin who proposed a path called sono-fusion to possiblly gain what was once called 'muon catalyzed fusion. Tha trick is a material with strong enough elasticity. Mercury is an example although a noxious poison in the body.....{as a kid we actually kept bottlles of the stuff to rub into quarters, and dentists mixed it with silver for silver amalgams for dental fillings. Many oldsters still have mouths full of the stuff in their teeth---how did we EVER survive, eh?}
Anyway mercury would be used to compress fusion 'hohlraums' (pellets) by being held in a spherical vessel in the center surrounded by mercury and many transducers outside bombarding it with ultra ultra sound. Rusi was run out of science and threatened with jail if he persisted in promoting his invention. UNFAIR!!
1 / 5 (1) Apr 29, 2018
According to the world's oldest surviving liiterature, the Rig-Vedas, the ancient spacecraft of the Ancients, the Vimana, used mercury in its propulsion systems. NO one knows really how truly OLD the Vedas actually are! Some say over 10,000 years which would put the ancient Hindu and Gujarati close to the oldest. Some records say the real oldest civilization was called Aratta and was in what is now Ukraine and in Roman times, Dacia. Largest Pyramid in the world there play acting as a mountain for millenia. Scientists are finding pools of mercury under pyramids in both China AND in South America that have up to now been claimed as 'Chinese' or Inca or Mayan or Olmec when really terrifically older. Probably find mercury under all the pyramids if one looks. No mercury exists as native liquid metal. Maybe the so called Annunaki used it for their ships as aids to sonofusion whose research is now almost illegal.
3 / 5 (2) May 04, 2018
Unlike intermittent renewables, carbon-free nuclear power plants have really decarbonized the grids.
"Nuclear Energy Is a Fast and Inexpensive Way to Improve the World" - Dec 2017
"Nuclear Energy Is the Fastest and Lowest-Cost Clean Energy Solution"
"Reducing the costs of nuclear energy in three steps" - April 30, 2018
3 / 5 (2) May 06, 2018
The specimen in question is 1 gram (0.04 ounces) of plutonium-239.
Very similar to Plutonium-239, in terms of radioactivity and chemical toxicity, Protactinium-231 (Pa-231) is far much more abundant in nature as Radium.
In a single eruption, volcanoes release hundreds of tons of radioactive materials: protactinium-231(equivalent to plutonium-239 in terms of toxicity), radium-226, uranium-235/234/238, thorium, potassium-40, rubidium-87, etc.
not rated yet May 07, 2018
Filling in the intermittency left by solar and wind means running the backup intermittently. Being technically capable of this is not the same as being commercially viable doing so; high revenues from shorter, intermittent periods are needed. The competition in this is not wind or solar directly but other kinds of load levelling, ie hydro, batteries, demand management. Innovation continues and no-one can know how the last stages of transition to near zero emissions will be achieved - or how much it will cost. Getting on with the early stages is our job. Even if those make "disruptions" they also create the incentives for fixing the final stages.

Nuclear will always have high levels of nuclear specific oversight and regulation (and related costs) that requires strong, sustained government support - but I think that can't happen whilst denial and anti-environmentalism are deeply embedded within mainstream politics and threaded through nuclear advocacy.
1 / 5 (1) May 09, 2018
Unlike coal and gas that need to be "greenwashed" by intermittent renewables, carbon-free nuclear power is the most ecologically friendly per unit of energy produced as it causes little or no impact on natural landscapes, wildlife habitats, birds and bats and other endangered species.
"We Don't Need Solar And Wind To Save The Climate -- And It's A Good Thing, Too" - May 8, 2018
"According to Bloomberg New Energy Finance (BNEF), public and private actors spent $1.1 trillion on solar and over $900 billion on wind between 2007 and 2016." with no meaningful CO₂ reduction.
"... Germany has deployed some of the most solar and wind in the world, its emissions have been flat for a decade while its electricity has become the second most expensive in Europe."

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