Comment by sightbroke
5 days ago
At the risk of coming off as a nay-sayer, let's say engineering hurtles related to fusion power generation is overcome. How is the presumably high upfront capital costs going to compare with the ROI?
That is, it would seem likely that fusion power would be costly to build. It would also seem apparent that if it were to fulfil its promise then the power it generates is sold at or less than the current amount. That would then seem to imply a lengthily time to make a return on the initial investment. Or am I missing something else with this equation?
> return on the initial investment.
It's not only initial investment. Half of the fusion fuel is tritium, which is one of the most expensive substances on Earth (a google search finds that the price of tritium is about $30k per gram [1]). For comparison, fission reactors need enriched uranium, and that costs only about $4000 per kilogram [2]. People have the idea that fusion produces many times more energy than fission, probably because fusion bombs have a higher yield than fission bombs. This is not true. The most typical fusion reaction involves one deuterium and one tritium and yields 17.5 MeV from a total or 5 nucleons. A fission reaction involves one neutron and one atom of U-235 and yields 190 MeV from 236 nucleons. So fusion yields about 4.3 times more energy per nucleon. That's respectable, but in the popular imagination fusion yields 100 or 1000 times more energy than fission, so the fuel cost can be neglected. Nothing could be further from the truth.
[1] https://www.google.com/search?q=tritium+price
[2] https://www.uxc.com/p/tools/FuelCalculator.aspx
The myth of unbounded / free energy from fusion comes from being able to use any old hydrogen atoms, rather than the much rarer deuterium and tritium.
Perhaps one day we'll get there, but I worry that the current advancements using the rarer isotopes will end up proving to be a dead end on that road, much like so many attempts at GAI. In the short term I suspect we'd have better odds with getting thorium reactors to be economical.
Deuterium is not rare at all. There's enough in your morning shower to provide all your energy needs for a year.
https://dothemath.ucsd.edu/2012/01/nuclear-fusion/
Tritium is rare but lithium isn't, and we can make tritium from lithium using the neutrons from fusion. (We also get tritium from fission plants, which is how we'd build the first fusion reactors.)
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No, it comes from foolishly thinking that the cost of fuel will dominate cost of energy. That doesn't require fusion of protons; deuterium and lithium are cheap.
I don't know much about this but I assume that the tritium will be created somehow while fussion is done [1]
[1] https://en.m.wikipedia.org/wiki/Deuterium%E2%80%93tritium_fu...
Agreed. I think fusion power would be great, but the sales pitch of 'limitless free power' just isn't true. The thought experiment I use is this: Let's imagine coal is magically free in every way. How does my power bill change? The answer is "barely at all" because the cost of utility electric power is mostly in distribution. We pay around 30c/kWh while the wholesale energy price is more like 2c/kWh.
It'll still make a difference in large scale energy intensive stuff, like desalination, aluminium refining, etc. but the average punter is going to save a lot more by installing solar panels.
We'll never know until (or if it ever comes) but there's reason to believe Fusion could be >50% cheaper than Fission.
That would still be more expensive than Solar and Wind (by 100% or more) - but I am skeptical in the same time frame those sources will be able to take over baseload generation.
It's really comparing apples to oranges.
Plus, it's a very hypothetical future. Anything could happen between now and then.
What is your exact scenario for cheap fusion?
Because IMO the only approach that is even capable of delivering here is the Helion one (=> direct conversion). And that design is incredibly far from ready, the whole approach is completely unproven and their roadmap is mainly wishful self-delusion (from what we can tell by evaluating past milestones, like "first 50MW reactor finished by 2021"-- there is no 50MW reactor even now).
From my PoV, ITER-style tokamaks are the most conservative/certain design, and also the furthest along by far. That would imply:
=> Cryogenics for the magnets
=> big hightemperature vacuumchamber for plasma
=> all the thermal/turbogenerator infrastructure needed in conventional plants
=> super high neutron radiation flux (this is a problem)
I just don't see where you save anything. This is basically just a fission reactor, only a magnitude more complicated and demanding. I absolutely don't see how it could ever get significantly cheaper than conventional nuclear powerplants.
Fission reactor has to be big and has to deal with storage of a lot of nuclear waste and must implement a lot of expensive measures to stop runaway reaction in case of unexpected events.
Fusion has none of this. Assuming Q >> 1 will be demonstrated in a design that can be commercialized the next biggest problem is dealing with high-energy neurons on a scale never experienced before with potential much faster degradation of materials than anticipated leading to prohibiting operational costs.
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Helion's promised dates were conditioned on funding, which they didn't actually get for several years. Adjusting for when they did get funding, they're pretty much on track.
Even if fusion is an expensive power source, it may still be desirable in areas which aren’t well suited to wind or solar.
If we figure it out, it might end up being cheaper than fission eventually.
Compared to fission? It's still quite unclear that fusion will provide improvements over fission.
Without any of the meltdown concerns a fusion powerplant is a lot simpler to actually build than a fission plant. It has a small fraction of the security, reliability, regulatory, etc concerns (not none, just way way less). Unless it's so marginal that it's barely producing electricity I'd be pretty surprised to find out we had Q>1 fusion and yet it couldn't out compete fission anywhere fission is practical.
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People won't be afraid of fusion, fusion plants can't be used to make bombs, fusion plants could maybe explode, but they won't poison the nearby land (or the whole planet) for decades-eons.
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There is a certain amount of "who cares about the cost" when it comes to fusion power. Nations will want to build them to lower or eliminate reliance on foreign energy, to address climate change concerns, and as a backup for renewables, and for other non-economic reasons. Many things that governments will want to fund that have nothing to do with directly "how much does the electricity cost?" or "when can we expect a return on investment?"
And the first generation will be expensive. That's how all new technology is.
The non-national-state investors care about the cost and roi.
And they’ll be subsidized such that they have a positive ROI
There's definitely an existential question around if fusion will ever be able to beat renewables plus batteries, but who knows with our energy demands ever increasing at some point renewables may hit a breaking point in land cost.
I'm generally pro-publicly funded research. There is not any direct ROI on say the LHC, but it does fund advanced manufacturing and engineering work that might enable other more practical industrial applications. The ROI might be a century away.
> At the risk of coming off as a nay-sayer, let's say engineering hurtles related to fusion power generation is overcome. How is the presumably high upfront capital costs going to compare with the ROI?
Does money even matter once fusion is attainable?
I'm not sure if you're being serious, but I'm going to assume you are. Let's say energy costs 1/10th it does today. That's far cheaper than I see anybody predicting fusion will be, but I think renewables will get there. How much does cheap energy change in the economy? What is bottlenecked by expensive energy at the moment? It turns out that matter, people, people's wants, still have a huge impact.
Make all energy free. What does that change? It lowers operating costs for many things, but up front capital costs are still there. Land still matters. Food still matters.
Money will still matter. Allocation of time, of resources, all that still matters a lot. Energy is big for the economy, but if its free we shift our focus to other matters of logistics.
If energy was truly free, it would revolutionize the economy and would fundamentally change how money matters.