Hacker News: pfdietz

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sun, 18 Oct 2026 02:08:49 +0000

> if by "now" you mean schedules proposed by all those fusion startups

No, I mean the impossible economics of their schemes. For example, the ARC reactor is about 40x the volume and mass of a fission reactor of the same thermal power output. It cannot possibly be competitive as a source of heat with a fission reactor. And fission is not competitive with renewables. So fusion is doubly cursed economically.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sun, 18 Oct 2026 02:05:12 +0000

Why do people keep repeating this ridiculous argument?

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 23:25:59 +0000

This is what you wrote upthread:

> All western civilization is built on 24/24 7/7 available energy (from direct use of petroleum or electricity).

Petroleum != electricity. You were talking about more than just electrical power. No goal post shifting!

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:43:26 +0000

Yes, it is possible. You need to penalize fossil fuels with CO2 charges, but that's needed to get a nuclear powered economy too.

Your argument about Germany is obviously BS, basically "it didn't happen yet therefore it can't happen". Solutions must apparently leap fully implemented into the world or else they are impossible, by your logic. Do you apply the same logic to nuclear, since no country gets the majority of its energy from nuclear (not even France)?

Storage can be dispatched, you know (and it's not just batteries.)

New comment by pfdietz in "Dam removals are bringing fish back across the northeastern United States"

pfdietz — Sat, 17 Oct 2026 22:40:36 +0000

Many of these small dams are also safety hazards because of the very hazardous horizontal vortex they create as water flows over them. Swimmers are caught in this and drown.

New comment by pfdietz in "Dam removals are bringing fish back across the northeastern United States"

pfdietz — Sat, 17 Oct 2026 22:38:38 +0000

They fill up with sediment and emit large amounts of methane from decaying organic matter.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:31:19 +0000

You're reading from the playbook of bad nuclear bro arguments.

The implication you're trying to draw there is a non sequitur. That situation doesn't contradict what I said. Moreover, France is going to be dragged kicking and screaming into the renewable age because they can't afford to subsidize nuclear builds enough to make a nuclear approach work.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:25:25 +0000

I don't think nuclear steam turbines use superalloy. Why should they? The temperature is not that high.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:23:36 +0000

I'm sick of people who make your completely bad faith argument, pretending storage doesn't exist or can't scale.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:22:33 +0000

> one should expect to see basically just the minimum amount of it to maintain grid stability / heavy industry

That minimum amount is none.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:21:49 +0000

A civilization that uses storage to level that intermittency. It's perfectly possible to power industrial world civilization using only renewables, and it would be cheaper than trying to do it with fission (which would require breeder reactors, btw.)

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:18:40 +0000

> I find it continually strange how much more attention solar gets than wind.

It's because solar gets cheaper faster than wind does. The experience rate is higher.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:17:12 +0000

It's not even competitive to use mirrors to get sunlight to heat water. PV is cheaper for that.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:15:35 +0000

Yes. They argue Helion screwed up computing the rate of energy flow from fast ions to cool electrons. I have not seen a good rejoinder from Helion, which is a very bad sign.

Given this, and given the apparent failure of Zap's scheme to scale, I don't think fusion has any significant chance of succeeding now.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:14:09 +0000

There could still be a great future in that from stored thermal energy from renewables. I harp on this a lot here; the estimated cost for 600 C heat available with 100% capacity factor is $3-5/GJ, just from resistive PV heat.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:12:01 +0000

Solar install is also easier and requires less exactitude, so training is faster and easier. Lose 1% of the modules in a PV field and your output is down slightly and temporarily. Screw up 1% of the welds in a nuclear plant and you're in massive trouble.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:10:15 +0000

Geothermal is not nuclear fission. It's some combination of primordial heat from the formation of the Earth (which was gravitational energy) and radioactive decay (which is distinct from fission).

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:08:27 +0000

It's not a shame it stagnated. It's good that it stagnated, since it wasn't competitive.

It's a shame it wasn't competitive.

New comment by pfdietz in "Solar surpasses nuclear power globally for first time"

pfdietz — Sat, 17 Oct 2026 22:04:24 +0000

> Want to build additional nuclear? First convince an investor to take the risk and operate on the free market

That's a bit cruel, because no such nuclear plant has ever been built and operated, anywhere in the world. :)

New comment by pfdietz in "How to Formalize All of Mathematics"

pfdietz — Fri, 16 Oct 2026 18:42:30 +0000

I wonder: can you get the AI to give you exercises that, when solved, would illustrate a point? This might require more theory of mind than they have.