I’ve been following them since they were giving promising lectures at MIT and I absolutely think they have the most solid approach! Tokamaks are well understood, they supposedly have the same plasma physics as ITER which has been heavily scrutinized and supported by work at JET, and their concept is simple - Tokamak but with very high field superconducting magnets using technology that wasn’t available when ITER was conceived, and apparently higher field strengths mean a smaller reactor for the same power gains. As a lay person the story is simple and that’s good! Then they demonstrated their magnets and got $2B in funding and now they’re deep in the construction phase for SPARC.

I encourage anyone curious to look up videos on SPARC on YouTube. It’s very encouraging! It seems honestly very reasonable that they will see sustained net energy gain for their entire power plant before 2030 (tho SPARC is still a demonstrator not designed for continuous service, so “sustained” means like one minute).

Here’s some videos:

8 years ago:

https://youtu.be/KkpqA8yG9T4

2 years ago:

https://youtu.be/KkpqA8yG9T4

Latest update posted yesterday:

https://youtu.be/w3Giq6NuPYs

I have a lot of love for CF. But when I talked to someone who actually knows about the stuff, the business plan of all fusion startups is basically to sell know-how/IP, once a state actor decides to go at it.

That's a good plan, but ultimately, it's going to be a state backed (that's why I have "non-state backed ones" qualifier). CF is going to have a reactor with fusion with Q>1, but commercial product?

China is working on MSR. It has employs something like 700 Phds and 700 support personel for over a decade and has only recently made a research reactor. That's what I consider a serious effort (and that's for far simpler technology).

In my opinion, people underestimate how brutally hard it is to make new technology to work reliably. E.g. Superphenix, sodium cooled reactor had a capacity factor of 7.9% over a decade of production. That was after they had a demo reactor Phoenix with capacity factor 65%.