The power is pretty bad, but it shouldnt be that bad. From my testing, it seems that the refraction generators have lower priority than every other power production method I set up on Hyarion, so they'll only actually kick on and start consuming pure light if your other stuff isn't enough. That might be why you saw such low numbers. My incredibly modest setup of a half dozenish rare ray collectors spanning 20ish chunks of area collects about 400 refraction light per minute, which works out to about 100MW (if I actually used pure light for power). The nice thing is that pure light is just a byproduct of beryl production, and you'll want a large refraction light farm set up when you go to make tellus science (if you're doing all the planetaris mods).
Honestly what bothers me is that this power setup is so late in the tech tree that you kind of need to solve the problem some other way anyway. By the time I had the ability to make the refraction generators I didn't need them. So heres some other ways to get power on this rock:
So first, you should set up a nice tilable grid of substations and refraction ray collectors to cover a nice large area. I've got ~600 square chunks of land area covered, just by virtue of all the land I enclosed within my walls, which nets me a pretty constant 140MW of power (twice what I need to power my tesla turrets to defend all this land). But lets never forget old reliable: Steam.
You see, Hyarion has access to large carbon deposits, and Arig (which you need for heavy glass anyway) gives you water collectors. Thanks to this, you can set up steam power using heating towers and steam turbines, with water collectors to supply it. Carbon is pretty terrible as far as fuel goes, but a stacked green belt of the stuff is still enough to supply 3.6 gigawatts of power using a heating tower's 250% efficiency, and only takes a half dozen or so big mining drills with a hundred or so levels of mining prod. It doesnt take up much space either, since you get to use the nice steam turbines at 500C (5 times higher operating temperature and efficiency than trash light)
Additionally, Hyarion has a fairly short day/night cycle of 5 minutes, so with all that otherwise unused land in your substation/lightning collector grid, you can still get a substantial amount of solar panels. Bonus points: hyarion gives lava and calcite, so you can practically make the solar panels for free. Even with -90% power (the same efficiency loss as the garbage pure light power), you can get about 1 MW per chunk in your base... making solar about 5x better in land use than refraction ray collectors.
