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billdietrich1 t1_ixpt295 wrote

Fusion probably won't be economically viable by the time we get it.

"Big" (thermal) fusion will be similar to today's fission plants, as far as I can tell, minus the fuel costs. Still a big complicated reactor, actually MORE complicated than a fission reactor. Tons of electronics and high-power electrical and electromagnets and maybe superconductors to control and confine and heat a plasma, or drive lasers to ignite pellets. You get a thermal flux (neutrons) to drive a big steam plant that drives a generator. So lots of high pressures and temperatures to control, lots of pumps and turbines and other moving parts. Still some radiation, not sure how it compares to a fission plant (some say more for fusion, some say less). No need for a sturdy containment vessel. Still a terrorist target, still need security.

Fuel cost is about 30% of operating cost [not LCOE, I don't know how that translates; some say fuel is more like 10%] of today's fission reactors. Subtract that, so I estimate cost of energy from fusion will be 70% of today's fission cost. Renewables PLUS storage are going to pass below that level soon, maybe in the next 5 years. [Edit: maybe I'm wrong about fuel for fusion, see https://thequadreport.com/is-tritium-the-roadblock-to-fusion-energy/ ]

And "big" fusion really isn't "limitless" power, either. All of the stuff around the actual reaction (vessel, controls, coolant loop, steam plant, grid) is limited in various ways. They cost money, require maintenance, impose limits, and scale in certain ways. You can't just have any size you want, for same cost or linear cost increase.

A flagship project, ITER, isn't going to start real fusion experiments until 2035, and the machine planned after ITER is the one that will produce electricity in an experimental situation, not yet commercial. So you might be looking at 2070 for commercial "big" fusion ? ITER is not the only game in town, but ...

Now, if we get a breakthrough and someone invents "small" fusion, somehow generating electricity directly from some simple device, no huge control infrastructure, no tokamak or lasers, no steam plant and spinning generator, etc, that would be a different story.

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Jobambo t1_ixqmngu wrote

Thanks for this comment. Too many people are still thinking fusion = free, easy, limitless energy for all.

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brettins t1_ixvbwx7 wrote

I'd be interested to know the rest of the operating costs for fission. As far as I know a fusion reactor breaking down is harmless and will just stop. I expect a lot of the operating costs of a fission reactor is related to safety and preventing meltdowns, which won't be a concern with fission.

I don't have actual numbers mind you, just speculating.

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billdietrich1 t1_ixvgds6 wrote

> As far as I know a fusion reactor breaking down is harmless and will just stop.

Well, in both fusion and fission there are a lot of "breakdowns" that can be far from harmless. You're dealing with high-pressure high-temperature steam, a big generator with high electrical currents, etc. In addition, fusion may have high voltages or currents in the confinement magnets and controls. These are not radioactive meltdowns or releases, but they're serious if something fails.

> rest of the operating costs for fission

Well, again, for fission and fusion both there are systems and moving parts that need to be maintained, replaced, etc.

> I expect a lot of the operating costs of a fission reactor is related to safety and preventing meltdowns

I wouldn't assume that. And the controls of a fusion reactor are likely to be MORE complex than the controls of a fission reactor. The other plant controls (steam, cooling, generator, transmission, etc) should be the same for both.

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Staerebu t1_ixx79xu wrote

Fusion made great sense in 2010 and before that, when solar PV had an LCOE of like $350 per MWh.

Less so now when we're hitting $40MWh, other than specific applications

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