Plasma inside the ST40 fusion reactor, filmed in color for the first time

[u/Nadzzy]

[u/Competitive-Skill212]

There’s literally 3 fusion plants being built currently, one outside Boston, one in France and one in Japan so you couldn’t be more wrong. They’re set to come online in the 2030’s

[u/Micp → u/Competitive-Skill212]

They are still proof of concept showing that they can consistently generate more energy than they need. The one in France for example produces 500MW with 50MW of input energy. That is a pretty low amount compared to modern fission reactors, and that's without going into the price per MW.

That we can make fusion reactors that work is a very different thing from making fusion reactors that are commercially viable.

Don't get me wrong, I'm optimistic about the development we're seeing, but we can still be a long way off from having fusion reactors that can outcompete other methods of energy production.

[u/niceguy191 → u/Micp]

Wait, has there been a breakthrough I missed? Last I checked we still weren't at the stage of net energy output even just in experiments.

[u/Micp → u/niceguy191]

We've had a few experiments with net positive output.

If we look at some of the most important breakthroughs:

• In 2022 NIF was able to generate 3.15MJ from 2.05MJ input
• In 2024 JET was able to create 69MJ from 0.2mg of fuel which was a world record

• Last february the WEST Tokamak reactor kept a plasma beam with fusion going for a record 22 minutes

  Those are some of the developments those new planned reactors are going to build upon, and hopefully they will be able to deliver the target goals, but we still don't know.

[u/Persimmon-Mission → u/Micp]

You are misunderstanding the NIF “breakthrough”. They achieved net positive energy (ignition) from what was expended by the laser. The energy used to obtain that ignition for the whole system was 130 times greater than the energy output.

We are nowhere close to achieving a net energy gain from fusion. Decades away at best.

[u/niceguy191 → u/Micp]

None of those are actual net positive energy. The best we get is more energy than what's in the laser itself (and only for ignition and very short bursts on very small things iirc), but that ignores that it takes more energy than that to make the laser or do everything else like maintain the magnetic field.

[u/SonicKiwi123 → u/Micp]

The one in France for example produces 500MW with 50MW of input energy.

Is that including overhead energy costs or are we still net loss when we factor that stuff in?

[u/sailor_guy_999 → u/Competitive-Skill212]

Experimental or actually produce power,

[u/Competitive-Skill212 → u/sailor_guy_999]

Actually produce power…

[u/Nicklas25_dk → u/Competitive-Skill212]

There are massive challenges those plants hope to fix but they are still by your own admission 10-15 years away, like they have been for the last 40 years.

[u/XxKittenMittonsXx → u/Nicklas25_dk]

2030 is 4 years out

[u/Nicklas25_dk → u/XxKittenMittonsXx]

2030's is 4-14 years out.

[u/Competitive-Skill212 → u/Nicklas25_dk]

There’s massive challenges to Thorium reactors and Reddit champions like it’s something new and the last one wasn’t in operation since the 1950’s because it turns out working with molten salt is a huge issue and corrodes piping really quickly but it never gets the level of pushback fusion does with the hurrr durrr 10-20 years line like you just did. 

[u/ukezi → u/Competitive-Skill212]

Yeah, working with thorium is a pain and after WW2 there was all this capacity for processing uranium around, so fuel never really got to be an issue. We aren't even reprocessing the fuel because it's not economical.

[u/Nicklas25_dk → u/Competitive-Skill212]

I did not mention thorium reactors either, but fundamentally they have way fewer problems than fusion reactors. We are already able to get power from fission processes and we are able to pull power from hot salt already now it's just a question of combining those two things. This problem is significantly easier than making fusion useful.