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Comment by hannob | Hacker News Reader

It is actually quite simple to convince industry: An industrial facility will do that if the incentives are aligned that it makes them more money.

The interesting thing is: The really challenging part of electricity storage isn't that much. Usually wind+solar complement each other fine. It depends on the location, but the challenge is usually something like 2-4 weeks in the winter when there's little sun and little wind.

I.e. an industrial facility would only need to shut down in a very limited timeframe to have a huge effect on grid stability.

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It is quite funny that in Germany every energy hungry industry is looking since the last decade to produce flexible enough to benefit from negative and cheap electricity prices during certain periods. Examples I know of first hand are graphite kathodes and electrodes (the process can be stopped for hours as long as temperature doesn't drip under a certain threshold) and paper. Continuous chemical manufacturing is having a harder time so, but they are looking into ways to store process heat for later use and generating needed heat for storage. Nothing came from that at on of previous employers so.

Funny is that these same companies, already now making a small fortune from these initiatives, are complaining about electricity prices and base load stability.

One of the best complementary sources to renewables are, besides existing nuclear plants, modern gas turbines.

How is nuclear a good complementary source to renewables? You complement renewables with a source of flexibility, not another source of inflexibility.

Stop spreading that myth. Nuclear isn't that inflexible, load following is possible and frequently done over here.

"Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope." from https://en.m.wikipedia.org/wiki/Load_following_power_plant

There are some differences between BWRs and PWRs, but the figures are not hugely different.

Of course nuclear is inflexible. It's entire economic case is built on operating at very high capacity factor. That reactors can TECHNICALLY operate at lower capacity factor is irrelevant -- the cost of doing so is prohibitive.

Economically, partnering renewables and nuclear doesn't work well. Nuclear does a very poor job covering for renewables intermittency, and renewables crowd out nuclear during the times they're churning out the power.

That is untrue as well. Inflexibility isn't the problem, the cost profile is. Yes, nobody likes running nuclear at half power, because fuel costs are minute compared to the building cost of the plant (Btw that is exactly analogous to the cost profile of renewables: almost all cost is in the building). So as long as you can regulate some pumped hydro plants that, shed some load, etc, you may save some money. Why don't we do load following with renewables, like e.g. shutting off some wind turbines? Same reason as for nuclear, plus some government regulations.

And in general, renewables do need a flexible supplement. So what would you suggest? More pumped hydro is impossible to build due to environmental regs, NIMBY and geography. Coal and lignite isn't flexible at all, and it is coal. Gas is extremely expensive to run, so expensive that there are gas peaker plants on idle for years in Germany. Also, they are burning gas. Bio gas is not available in sufficient capacity. Battery storage might be an option 30 years from now when enough old EV batteries are available on the cheap. But that will prevent recycling them into new EV batteries and need even more resources like lithium and cobalt. So the alternatives to nuclear like coal and gas are worse, and only still in use because they don't pay fair a price on their carbon emissions.

No, it's not untrue. If you optimize a CO2-free grid for minimum cost, you will find that the solutions don't usually involve both renewables (particularly wind) and nuclear. Either nuclear is so expensive it goes to zero, or its so cheap it dominates. There's little synergy between renewables and nuclear.

This also happens in unplanned grids where market forces are being allowed to operate. Renewables, if they are cheaper per kWh than nuclear, drive down the price sufficiently often that nuclear struggles (and with production subsidies, they can drive prices negative, but never mind that). Today, even existing nuclear plants are struggling to make an operating profit in the US.

> And in general, renewables do need a flexible supplement. So what would you suggest?

For the moment, this would be natural gas. If you object to the CO2 from this, consider that to compete against NG CC for BASELOAD in the US, new nuclear would need a CO2 tax of $300/ton or more (see below for quote and link). For new nuclear to compete against NG to cover renewable intermittency, the CO2 tax would have to be much higher, perhaps $1000/ton or more, depending on the fraction of time the NG generators are needed. This is a ludicrously high CO2 tax, and shows how far out of contention new nuclear plants would be.

In the future, this last resort generation could be replaced with something like hydrogen (either produced from NG by SMR with CO2 capture, or from renewable energy by electrolysis.) And it would still be cheaper than new nuclear.

> Gas is extremely expensive to run,

No. Quote from Physics Today (Crane was the president of Exelon):

https://physicstoday.scitation.org/doi/10.1063/PT.3.4088

“The cost of new nuclear is prohibitive for us to be investing in,” says Crane. Exelon considered building two new reactors in Texas in 2005, he says, when gas prices were $8/MMBtu and were projected to rise to $13/MMBtu. At that price, the project would have been viable with a CO2 tax of $25 per ton. “We’re sitting here trading 2019 gas at $2.90 per MMBtu,” he says; for new nuclear power to be competitive at that price, a CO2 tax “would be $300–$400.” Exelon currently is placing its bets instead on advances in energy storage and carbon sequestration technologies.

(Since then, Exelon has announced they want to spin off all their nuclear generating assets.)

> More pumped hydro is impossible to build due to environmental regs, NIMBY and geography.

More pumped hydro ON EXISTING RIVERS is geographically constrained, but off-river PHES much less so. It has vast potential in most parts of the world, especially when coupled with long distance transmission.

Nuclear would need to get cheaper than current nuclear methods.

How to get rid of excess complexity in regulations while still retaining good safety... I have some ideas.

Even with zero regulations, nuclear would still have a cost problem. Just the steam turbine part of a nuclear power plant is more expensive than renewables. Coal is uncompetitive for the same reason.

When I see "less regulation!" talk, I want to ask "so, you're going to do away with the expensive parts, like the containment building?"

If new nuclear is going to ever be plausible, it has to be some fundamentally new (like reactors with molten salts) that don't need massive containment buildings that can safely contain large volumes of steam in accidents. Such reactors will not be commercially viable soon.

The containment isn't the most expensive part, the pressure vessel is. Single forged part of some magic stainless steel alloy able to withstand 300bar at 500K and high neutron flux costing a billion or more. Gen4 reactor designs try to do without that by having the actual core non-pressurized, e.g. in molten-salt reactors or pebble-bed reactors. The other idea is making a loss-of-coolant-accident harmless, thereby getting rid of the necessity to have too many redundant ultra-expensive cooling systems (current EPRs are at quadruple-redundant...). The problem with regulation there is that those novel designs are currently still regulated based upon the aforementioned PWR/BWR reactor designs (so your coolant system has to have X amount of redundancy, the reactor vessel must withstand Y amount of pressure, ...), forcing unnecessary cost that isn't necessary because the possible accidents and conditions are completely different.

> The containment isn't the most expensive part, the pressure vessel is.

I was referring to the expense introduced due to regulations. Or are you saying that one could make a much cheaper pressure vessel without those pesky regulators?

Gen IV reactors have the property that they aren't available now, and won't be available and matured anytime soon. Many also have aggressive operating profiles that will stress materials. No one is going to want to buy a MSR only to discover corrosion limits its lifespan to 20 years. So, getting them to a state that customers would be comfortable with will take a long time.

Gen4 reactors are an active area of research, but it isn't like there are none. Some concepts go back decades, as do prototypes like THTR-300 that actually produced power for a few years.

That stress will limit the lifetime of a reactor is true for any reactor. Any BWR or PWR has a maximum lifetime set by the pressure vessel, because that is the one single component you can neither fix nor exchange. As soon as mechanical stress, neutron embrittlement and temperature gradients have done a certain amount of damage, the plant is finished. But even for currently operating reactors, we are still exploring how long that will take exactly, by regularly checking the materials in the running reactors, because no one ran a prototype for 40 or 60 years. And you cannot compare with other models of reactors, because they are usually very different in operating parameters, materials and design.

We currently do not know what a few decades of operation will do to a MSR vessel, but the point is that trying it out has been hindered for a long time by regulations that are not fit for that type of reactor. So you arrive at a costly chicken and egg problem, where a regulator asks for a proof (ideally a proof by pointing at a working prototype with a few decades of maturity) just to allow you building a prototype.

THTR-300 is an example why there's a large gap between concept and commercially proven reactor design. The THTR-300 was a huge disappointment, with major, showstopping design flaws. The Gen IV concepts being bandied about now will have to go through a long, drawn out process of technical maturation before any large scale deployment can occur.

The companies doing serious work on molten salt right now, are mostly in Canada because of regulatory structure. They had to develop their project with very limited funds and totally uninterested governments (until recently in Canada).

Yes they are not available now but they could be available in this decade and by the 2040 you can build 100s if you really actually put some resources behind it.

These designs are infinity easier to scale then what France did.

Of course that kind of planning is not really how the US does things but at least they could seriously get behind a few prove of concept projects. Currently its not even possible to get a non PWR reactor regulated at all.

2040 is 19 years away. In the last 19 years PV module cost per W (adjusted for inflation) declined by a factor of 25.

I think the potential for cost reduction in nuclear is far bigger.

There is no inherent reason why a small reactor couldn't be mass produced. In a perfect world you would have a factory spitting out finished nuclear reactor every day.

Transport it to a site, drop it into a concrete hole, connect the salt loop and plug in the refiling pipe.

It really shouldn't need much operation other then planning how much to refuel.

We have gotten used to thinking of nuclear reactors as these civil engineering projects with large costume one of designs, but there is no inherent reason why you can't produce them at comparable to speeds other items of that size are built. Really once you have the material qualified a nuclear reactor is in some ways simple then a rocket engine or an airplane.

The problem in days world is that you need to get threw regulation (in the US factually not possible, and requires complex engagement with every countries regulatory scheme) and then you need enough costumers that you can actually invest in the assembly line.

No, you're putting words in my mouth.

Safety could be actually improved by doing more efficient regulation.

This is not a great way to look at it. Modern nuclear wouldn't use the kind of steam turbines that are currently used. It would either use the same turbines gas plants. Some concepts use even more modern turbines but those are not commercially proven.

However if there was serious commitment to nuclear, these things would be sensible to develop also.

Your overall point is well taken, nuclear is better when running at full capacity, even if I would argue that with a modern reactor with less operational cost this would be less of an issue.

That however is exactly why many nuclear plants in planning today will actually heat up molten salt and use that to drive the turbine. So there is basically a built in flexible heat battery.

The idea of most modern approaches is actually to have more generation power then the reactor actually provides, and have a heat battery containing in between. This makes sense as you have to have a salt loop anyways, so adding a larger tank isn't really a big extra cost.

Additionally it means that the nuclear build of your project is actually a smaller % of the cost with everything outside of the nuclear boundary being pretty standard salt loops and turbines. So you might build a 500MW nuclear plant with 1.5GW turbines plus a big tank full of salt. All the turbines and the salt tank have essentially nothing to do with nuclear or nuclear regulation.

However if we had started to seriously consider this in the 60s/70s/80s, establishing wind and solar would never even have made any sense outside of some niches. You build nuclear plants that can load follow without issue and accept the capacity problem. Clever engineers and business people would have soon realized that the salt loop can double as a heat battery.

The problem is simply that all these issues were not seriously considered in the past. Basically the Navy wanted PWR for submarines, because those got so much development the largest contractors and the government picked it up for civilian power. Once all the large nuclear companies had bought in to that, they no longer want lots of research on other types of reactors, so not even the nuclear industry advocated for such projects. Combine that with the general turning against nuclear and you basically get massive stagnation.

Unfortunately all the Molten Salt based nuclear work was done in Tennessee, a place that was not very relevant politically. There is even a famous call where Nixon basically says, moves all that potential money to projects in California.

> Just the steam turbine part of a nuclear power plant is more expensive than renewable

If you are building a new nuclear plant to target the Rankine steam cycle at a lousy ~140°C inside an enourmous concrete bomb, you are doing it wrong.

The cool kids are targeting the Brayton cycle at ~700°C and atmospheric pressure.

https://en.wikipedia.org/wiki/TMSR-LF1

The overall goal is to reduce CO2 emissions as much as possible. That alone favors nuclear (existing plants, not new ones) over coal and oil. That gives you stable base load without any CO2 issues. supplement that with as uch renewables as possible and flexible gas plants for ad-hoc peak demand. Phase out nuclea once renewables can provide that power (storage solutions and so on).

Wind and solar were already a lot cheaper than Hickley C a couple of years ago, so that question is not about costs.

I think the comment you are replying to is suggesting go full wind and solar rather than building further nuclear (with gas peakers until we sort out storage as you suggest - but that's the same with both renewable and nuclear). You could say build nuclear in the meantime, but nuclear takes a long time to build, so it will likely to quicker to build the renewable solution. In which case there is no meantime.

I don't think anyone (on this thread) is suggesting that we phase out already built nuclear capacity before it's planned lifetime.

Terrapower is using molten salt instead of water: they can produce 150% output for five hours. Unfortunately they only just started building a demonstration plant.

If you have a high-capacity, constantly running power source, you can subtract that power from the demand curve, up to the minimum power demand.

That means the winter renewable production troughs on dark, windless days become more shallow. Since the requirement on installed wind and solar capacity is driven by how many Watt-hours you need to overproduce so that they can be stored for sunless, windless days, that ends up drastically reducing how many solar panels and wind turbines you need.

You can test this in the model.energy simulator that you linked by simply subtracting a value from "constant electricity demand". I just did that using realistic values for Germany - reducing the constant electricity demand by 20GW from 66 to 46 GW (roughly the peak capacity of nuclear plants in their heyday) leads to a reduction of peak renewable capacity from 537 to 358 GW, basically exactly a factor of 1.5.

You'll still need a flexible source of course to get rid of the oscillations over the minimum demand.

If you look at the solutions at model.energy as you vary cost assumptions, the solutions go from 0% nuclear to 100% nuclear in a step-like manner. It's almost never the case that the two get mixed. There would be some mix in a variable demand scenario if (for example) some of the demand varied along with insolation. But in the baseload case, it's like Highlander.

Not sure if you're referring to a different simulator since model.energy doesn't seem to allow modeling nuclear?

But, qualitatively, it sounds like the step-like behavior you describe simply reflects whether LCOE(nuclear) > LCOE(renewable+storage)?

That wouldn't tell the whole story though, since you might still want to keep the number of nuclear plants low, or you might simply be thinking about whether to keep operating existing plants, rather than building new ones.

You can turn on nuclear (look under the advanced assumption setting; it's called "Dispatchable technology 2" for some reason.)

And yes, this modeling site is about designing an energy system from scratch, not operating existing plants.

this toy model use constant load, ignore grid cost, inertia needs, multi year weather pattern on renewable production other most sophisticated model can disagree with your observations

The grid can only handle so much energy instability. So in that sense stable sources such as nuclear can be complements to unstable sources.

Are you talking about short term frequency stability on the grid? This was provided by large rotating mass of conventional generators, but today that stability can be provided far better by batteries. The Hornsdale Power Reserve in Australia (that thing Elon Musk has built) made a killing off FCAS, which doesn't require more than a fraction of an hour of battery capacity.

https://en.wikipedia.org/wiki/Hornsdale_Power_Reserve

You are mixing up frequency control and inertia, Hornsdate brings FCAS but no inertia, it would need grid forming inverter.

Hornsdale is testing a synthetic inertia mode that will supply half the inertia needed by SA.

https://hornsdalepowerreserve.com.au/learn/

The weather is fairly predictable these days. Nuclear is inflexible, but it's human-controlled inflexible, so you can run it at complementary times to reduce the amount of flexibility needed.

1) corty addresses the inflexibility myth

2) there are always going to be Capex-dominated industries running full-bore 24/7 that need base power with the same power gen profile. Nuclear is perfect for this.

You exactly want to complement renewables with inflexible. You want 100% of your "DC component" of your load profile handled by base load power plants, and maximizing the utilization of power storage by variables.

You repeat the canard that baseload demand requires baseload supply (from individual power plants with high capacity factor). This is nonsense -- the grid allows baseload supply to be synthesized from intermittent and dispatchable sources. The consumer doesn't care where the energy is coming from.

Even consumers that have their own baseload requirements and are not on the grid don't necessarily want baseload sources. An example is mines in Australia, which are installing batteries to work with solar and combustion turbines (for the latter, they allow the turbines to run at full load for a while, then turn off, which is more efficient than operating at partial load.)

Why do you think so many crypto miner companies are moving to Texas? They want to be paid by ERCOT to not draw power during peak times.

Yes, ERCOT will actually pay them money, if they’re not drawing power.

Chinese crypto miner companies are moving here, and taking over old aluminum smelting operations, kitting them out with tens of thousands of crypto miner computers, and then getting paid for not turning them on.

That's... an impressive twist on Proof of Work. Threat of Work?

Have you ever run such a business?

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