But solar isn't built like nuclear. Solar involves parallel exploration of device designs at very small scale, installed with massive redundancy and resilience. Many billions of PV cells have been manufactured. The real cost decline driver is manufacturing automation. Nuclear, even SMRs, have orders of magnitude coarser granularity.

If you want "hot rocks", it's probably much cheaper to just resistively heat them with cheap solar (you don't even need inverters). This could store energy over many months and, pushed to its cost reduction limits this promises to be the final nail in the coffin for any dreams of a nuclear revival.

https://news.ycombinator.com/item?id=45012942

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southernplaces7 3 days ago | parent | next [-]

>But solar isn't built like nuclear. Solar involves parallel exploration of device designs at very small scale, installed with massive redundancy and resilience. The real cost decline driver is manufacturing automation. Nuclear, even SMRs, have orders of magnitude coarser granularity.

Because the level of permitted development without being crushed by onerous regulatory burdens has been absurdly hamstrung on nuclear. All of the issues you add as "but" cases are things that many different innovations in a fluid market for research could have refined. The same has been done for many complex technologies over the decades, yet for nuclear there's always some excuse like the ones you mention. The comment you replied to is right. We're talking about something that since decades ago could have been improved enormously, and hasn't been thanks to a multitude of stupidities.

The United States Navy trusts extremely compact reactors (designed and working despite the DoD's notoriously lax financial and schedule stringency with defense contractors) to power its absolute most important, costly, defense-crucial war machines, and regularly docks them right inside the country's (and world's) largest urban areas, but somehow there's just no way to make nuclear power for civilian use more compact, cheaper and effective?

	▲	pfdietz 3 days ago \| parent [-]
		The regulatory burden argument doesn't explain why renewables are trouncing new nuclear in China. I view it as a universal excuse nuclear fans trot out to explain away inconvenient realities. They also never explain how the regulatory burden would be reduced in a way that doesn't compromise safety. And regulated safety is the price the nuclear industry pays for liability limits.

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mikestorrent 3 days ago | parent | prev | next [-]

> Solar involves parallel exploration of device designs at very small scale, installed with massive redundancy and resilience.

I am imagining a field of shipping-container sized units, each of which is a small modular reactor. Probably with solar panels on top ;) Still a few orders of magnitude different, but the idea here is that each unit is small enough that it can be manufactured, so that nuclear plant bring-ups don't take 30 years. Most of the cost is because of the tremendous generational effort involved in just a single project; what does it take to reduce the cost of the plants themselves to the point where they can really shine, economically?

The goal is to have reliable base load power generation so that we don't have to deal with the massive complexity and carbon footprint of battery plants all over the place to deal with peaky generation technologies like solar. I don't believe that that is a solved problem: using tremendous amounts of rare earth materials for limited-lifespan installations that don't even produce energy is possibly not the best use of our resources, considering it's almost all fossil fuel going into those logistics operations anyway, right? EROEI for a battery plant is going to be hard to achieve.

	▲	pfdietz 3 days ago \| parent \| next [-]
		NPPs that small are a nonstarter, due to loss of economies of scale. Even SMRs are creeping up in size now to try to recapture the economies of traditional gigawatt power plants.
	▲	aledalgrande 3 days ago \| parent \| prev [-]
		Your shipping container mention reminded me of The Box, a book that explains how shipping was so erratic, risky, slow, unreliable and incredibly expensive before the standardization into containers. Containers literally changed the world economy. I think you are onto something. But this requires upfront investment, which alas, politicians are not for.

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deepnotderp 3 days ago | parent | prev [-]

Thermal storage has very poor discharge rates unfortunately (usually slower than a day), as well as surprisingly high cost once you factor in inefficiencies and turbine cost

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pfdietz 3 days ago | parent [-]

As was repeatedly explained in that other thread, thermal storage of the kind described there is inherently a long term storage technology, and this drives the design to minimize capex, not maximize round trip efficiency. The focus on efficiency is fundamentally misplaced there, as it becomes orders of magnitude less important compared to diurnal storage (which batteries appear to be well on their way to dominating.)

Long term storage and diurnal storage are complementary technologies, sort of like the different levels of cache and main memory in a computer memory hierarchy. Combining them appropriately reduces cost vs. using just one of them.

Anyway, the technology as described would produce heat at 600 C for as little as $3/GJ, which nuclear would have a hard time competing with.

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deepnotderp 3 days ago | parent [-]

$3/GJ is $108/MWH which any large scale fission buildout would easily beat for thermal energy costs

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pfdietz 3 days ago | parent [-]

You misplaced a decimal point. A MWH is 3.6 GJ, so it's $10.8/MWH.

$3/GJ is about the current Henry Hub price for natural gas, and as you should know cheap natural gas like this is what killed the "nuclear renaissance" in the US.

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deepnotderp 3 days ago | parent [-]

Oh my bad, you’re right

Re: Nat gas, agreed, it’s not solar though, storage is much more expensive

Thermal energy still needs to drive a turbine to generate electricity

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pfdietz 2 days ago | parent [-]

Sure. 600 C is about the temperature of steam in a coal fired power plant, so one of the use cases here is to take an old coal plant and replace the heat source. It's much higher temperature than the steam in a LWR, so the turbine can be smaller and cheaper. Also, no steam generator is needed as in a PWR.

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deepnotderp 2 days ago | parent [-]

Yes but one of the reasons that coal is being replaced by gas is because of the capex of the steam turbine

	▲	pfdietz 2 days ago \| parent [-]
		Yes? That doesn't mean the capex of a steam turbine for this application would be unaffordable, or that this wouldn't have superior economics to nuclear (which also has a steam turbine, and a more expensive one).