[gaadd33]

Why will fusion arrive in the next 40 years? I feel like that's what was stated 40 years ago too. Are there 0 barriers at this point and it's just a matter of obtaining funding and starting to build plants and by then there will be a big enough track record for widespread deployment?

[ztjio]

Despite this attitude being memed, multiple efforts to refine fusion reactors to the point they are useful for energy purposes have made fairly constant (albeit slow and incremental) progress over the years. Furthermore, all the science and engineering concepts are sound based on the physics models.

One thing people don't get is we only need a tiny fraction of net positive output due to the insanely large amount of fuel available to us. 2-3% positive output is all we're talking about and it'll be able to economically replace most other energy sources (though it will take time to ramp up of course.)

Basically it's just a matter of time and continued advances in material sciences. Purity of materials and perfection of manufacturing are the primary barriers. Operational consistency a secondary one (and continued improvement in microcontroller tech and data analysis/AI/etc. will help here.)

One example, in focus fusion, the current progress has definitely been incremental but basically every step of the way the progress has been hindered by exactly the same problem: the materials and apparatus have to be nearly perfect to increase plasma duration sufficiently; to avoid contamination of the self-sustaining plasmoid. And indeed, the progress on that end has been continuous. Once it's proven it will be a matter of perfecting the manufacturing process and automations/etc. to ensure that degree of material quality and device engineering and voila we'll have cheap scalable power.

Based on what I've been watching for the last 15 years, I think within 40 years is quite reasonable. In fact, I think it would not be a surprised to see consistent 0.5% net positive or better in the next 5-10 years, whether it is focus fusion or tokamak or whatever.

TL;DR: Fusion is a 100% sound energy generation avenue that is simply waiting for its "welding" moment. By which I refer to the point where gas production became suddenly economically viable due to the invention of welding (which was motivated at least partly by the desire to improve gasoline production.)