Will fusion provide >2% of US electrical power before 2050?

IMHO, if fusion ever gets commercialized it'll be first and primarily as a neutron source for high-burnup fission reactors and breeders. Each 24MeV D-T fusion releases a very high-energy neutron that can trigger a 200MeV fission. If you're doing fusion alone, those valuable neutrons mostly go to waste.

predicts NO

@JonathanRay To elaborate on this, what’s a better use of a neutron:

Try to get deuterium to absorb it (extremely low cross section) so you get tritium which is difficult to fuse for 24mev to get your 1 neutron back. Maybe you can just barely break even on neutron economy here using expensive beryllium’s n-2n reactions if everything is perfectly designed to conserve neutrons.
get any of a zillion fertile heavy isotopes to absorb it (large cross sections) to get a fissile isotope which is relatively easy to fission for ~200mev and get 2-4 neutrons back

I doubt fusion alone will ever be an economically competitive utility scale electricity source

@JonathanRay you're absolutely spot-on with this -- even if we solve the tremendous technical challenge of Q>1 engineering breakeven, the enormous capex + opex of a fusion plant and fusion fuel makes economic breakeven seem very unlikely. I would be shocked if by 2050, commercial fusion power hit the ~20 c/kWh needed to compete with even gas peaker plants, let alone ~10 c/kWh baseload nuclear fission or <2 c/kWh peak solar/wind. Technological advancements can make a lot of previously unimaginable things possible, but at the end of the day fusion won't make a dent on the grid if it's not profitable to do so.

The saying has been "fusion is 30 years away" for 50 years, but I think we've reached "fusion is only 20 years away". As an optimist, I take that to mean a 20% chance of actually getting there within 30 years.

Interesting question, thanks for asking! The main thing I knew about Helion is that Sam Altman invested, but I'm wondering if there's a way to more specifically profit off your belief that they are the next Theranos, especially through Manifold. Baseline, you could ask questions like "Will Helion hit X target by Y date." More interesting might be some index that tracks Helion's eg number of positive press mentions or valuation/size of next round? And then ideally find a Helion believer to take the other side of the trade.

Starting very low because D-D requires much higher temperature than D-T and we can't even break even with D-T yet and T/He3 fuels are prohibitively expensive until you solve D-D fusion. The number of neutrons produced from fusion will be nowhere near enough to breed as much T from Lithium as it consumes. Maybe excess neutrons from fission plants can will be used to produce enough T for a few reactors, but fusion is probably never going to provide a large fraction of grid power. I want Helion to succeed but based on my understanding of the physics I'm 98% confident that they're the next Theranos. They claim they'll be able to break even with D-D but nobody else has even solved D-T yet, and that's orders of magnitude easier.

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