[derriz]

I think a line from the end of the article - part of the bear case - "fusion is just another in a long line of energy technologies that boil water to drive a turbine" - should be at the start.

The entire premise of fusion generation is based on world view where the limiting factor for generating electricity was the cost of providing fuel for combustion to generate heat. This thinking was pretty natural if you looked around the world in the first half of the 20th century when coal and steam engines were still kings of energy. This was a pre-semiconductor and pre-plastic age. That's why they ended up using long of fairly primitive technologies: a chemical (combustion) process to generate heat, a heat capture process to boil a tank of water, a mechanical process to convert the steam pressure into mechanical energy, and an electro-magnetic process to extract usable electricity.

But in an age of advanced materials and semiconductors, it feels more and more that fusion is an attempt to solve a problem that is no longer really relevant. Working towards a "better" heat source for an electricity generation process which still involves steam-age tech is akin to trying to breed faster/cheaper horses to improve modern transport.

The cost of fuel is almost negligible for fission - non-fuel operating costs are killing off perfectly functioning nuclear plants like at Indian Point[1] - so the problem that fusion will "solve" is not actually a significant problem.

I'm convinced that we have moved beyond boiling water and generating heat, etc. in electricity generation. We no longer need massive steam engines to generate electricity. Modern technologies like wind, solar and batteries dispense with all this cost and complexity and the shackles of Carnot efficiency.

[1] https://en.wikipedia.org/wiki/Indian_Point_Energy_Center

[walleeee]

Neither semiconductors nor plastics shift the energy generation paradigm. "Advanced materials"- alright, well, which ones? And do they give us a better return than good old steam?

Wind, solar and batteries are products of combustion-fueled industry. The extent to which we have electrified the world industrial base is minimal, and to do so at the current scale on the basis of wind and solar would take a larger quantity of several metals than is available in the crust, to set aside the consequences of a massive expansion in mining, the poor recycling rates for most of the relevant materials, and the fact that, even with a much-improved recovery rate, this would only buy us on the order of several hundred years.

A more promising energy production system for a resource-limited world is thorium molten salt, which is comfortably Carnot in spirit, relatively cheap and easy to build, fuel and operate, no danger of meltdown, no "dual-use" for weapons, can consume existing nuclear waste... And we would do well to explore alternative battery chemistries as lithium is neither unique nor optimal, simply popular, and our hunger for it at present seems to be motivating some unpleasant political machinations.

[derriz]

You really believe it would have been possible to construct a modern wind turbine with the materials available in 1950?

Yes they do give a much better return than any thermal source according to any recent study of LCOE I've come across. Reflected in investment numbers - renewables account for 70% of new global capacity added last year.

Wind, solar and batteries are products of an energy intensive process NOT a combustion based process.

The shift to electricity as the primary energy source is well underway in multiple industries and sectors. Growth appears slow because industrial equipment is built to last decades. In transport (equally as energy hungry as industry), it's happening a lot faster as with domestic (induction cooking and heat pump sales).

Thorium molten salt, promising? You mean they were back in the 1950s/1960s in Oak Ridge? The first experimental molten salt reactor ran for a few days before springing a leak and being decommissioned. Or the later one in the 1960s which ran for 4 years (only managing to operate for 40% of the time)? There's a whole bunch of reasons that the PWR emerged as the dominant nuclear generation tech from forest of experimental reactor designs in the mid 20th century.

[walleeee]

> You really believe it would have been possible to construct a modern wind turbine with the materials available in 1950?

Sure, modern materials make for a more modern wind turbine. But they don't shift the paradigm. Nothing has since fission, right?

> Wind, solar and batteries are products of an energy intensive process NOT a combustion based process.

The fact remains that energy intensive industry is currently accomplished mainly via combustion. The degree of electrification is small and an effort to fully electrify faces what appear to be prohibitive resource limitations. If you have any ideas on this point I would be interested to hear them.

Electrification is happening in personal transport. We have made minimal progress towards an electric shipping fleet, electric air travel, electric trucking, etc. And if we do begin to make serious progress, it will come with serious environmental (and likely political) costs.

Oak Ridge was a testbed. The Chinese have an MSR that has been selling power to the grid for several years. Copenhagen Atomics is building them to fit into shipping containers. Is this not enough to prove the technology viable? The main reason traditional fission became dominant, as I understand, is that it allowed nuclear-capable nations to conceal nuclear weapons programs with energy programs. And once the supply chain and institutional expertise gets some inertia, it is hard to change tracks.

[derriz]

Modern wind turbines absolutely have shifted the paradigm - both in size, efficiency and durability. Across the globe, demand for new turbines in the market is insatiable. No other electricity generation technology (even nuclear in its heyday back in the 1980s) has grown as fast as wind has in the last 15 years - although I expect it's soon to be overtaken by PV growth. It's likely that this year the amount of electricity consumed globally from wind turbines (around 2.5TWh) will match that of nuclear reactors despite nuclear's 60 year head start in grid scale operations.

But the most obvious difference, and that which contributes most to the paradigm shift, is the difference in price.

The existence of technology alone isn't enough to shift any paradigm - the tech has to be relatively cheap - transistors were a curiosity until they became cheap and then they shifted the paradigm, same thing happened with integrated circuits and nearly every technology breakthrough in history.

Batteries, PV and wind turbines are mass-produced and their prices are falling as you'd expect given the expansion in production (between 80% and 95% in the last 15 years). This has been the way since Henry Ford and is not going to change. What is also inevitable is that once mass-production is introduced into any human endeavour, then the existing technology is doomed.

The TMSR-LF1 in China has not being selling into the grid for several years. It was never envisaged to do so - it's absolutely tiny (only 2MW) and it's intended that it will operate intermittently for the first 5 or more years before they try running it continuously. This is a science experiment, not a viable commercial reactor. The 2nd Oak Ridge reactor back in the 1960s was 7 or 8 times bigger - although it never managed to run properly and only ever achieved 7MW of output.

I really don't understand why thorium liquid salt reactor enthusiasm is widespread. It's just one of endless reactor designs which failed to make it into commercial operation because of a host of genuine technical/engineering reasons. Just read the wikipedia page[1] - the list of disadvantages is longer than the list of advantages. For every problem it solves, it introduces several more.

[1] https://en.wikipedia.org/wiki/Molten-salt_reactor

[walleeee]

It's not enough to count the problems in the list, you also weigh the ones it solves against those it introduces. I'm not a nuclear engineer, but none of the issues seem insurmountable, and some are addressed in modern designs. I see a few big advantages:

1) Apparently much lower resource requirements for construction, maintenance, and mining/refining the fuel, than for traditional nuclear power, and also (!) the wind and solar equivalent. We don't have the metals, as far as we know, to maintain a fleet of wind turbines, solar panels, and batteries for very long without an almost perfect recycling rate.

2) Some designs can consume spent nuclear fuel. This is a more cost-effective (and more sane) option for disposing nuclear waste than burying it.

3) Steady availability. Wind and solar are unreliable, so you need a buffer, which means batteries (or pumped hydro, or rapidly spinning hunks of metal, or something).

Mass production is a force to be reckoned with, and the cost of wind and solar has fallen relative to other power sources, but given the dominance (still) of combustion, this not only reflects economies of scale in manufacturing wind/solar equipment, which I don't by any means deny, but it reflects also the rising costs of of legacy fuels. It is not getting easier to find coal, oil, or many of the metals we use to manufacture energy systems and the material economies they sustain.

It seems to me we need an energy system that can function reliably in a world facing resource shortages and other stressors, and in this context smaller scale, modular power plants may even be an advantage.

I know TMSR-LF1 is small and a research program; I thought it had sold some power, but might have been misinformed

[vincvinc]

Would be relevant criticism but here’s fusion startups skipping the “boiling water” step - see Helion Energy (Sam Altman funded)

[tuatoru]

On paper.

[pfdietz]

This is why I call them the "least dubious" fusion effort. Sure, things have to break right for them to succeed, but at least they have a chance, unlike tokamaks.