AM, Quarks & Tech Levels
Well, as far as I can tell AM (anti-matter, not to be confused with AM
2 of
Sten fame

) is being studied, manufactured and even stored these days on good old Terra. Now truth is we, iIrc, don't have a lot of AM, but CERN or possibly Fermi Lab have or had some AM in storage and that was back when I was a kid. (I can still see the scientist looking over his shoulder and spouting off the number of anti-hydrogen particles they had in storage, it had a six at the beginning, I think it was 6K, close to seven.) Still not enough around to power much, and mostly still used for study.
However, extrapolating from that figure in a few TL, say TL-A+ we should be ready to begin using it as a power source, possibly.
Now since we know that by (OTU) TL-F subatomic particles are used for both communications and warfare. Quarks, which again we can liberate right now, to be used as power source, well, that sounds to me like high teens, for experimental for sure, and possibly even prototype power plants, and even those might require large colliders or some such to either liberate or trap the quarks.
Of course I am not a scientist, I merely play one now and again on the net. YMMV.
Hope that helps,
Laterness,
Magnus.