8 min. x 60 s/min. x 20 t/s x 800 EU/t / 256 B = 30,000 EU/B
So, roughly the same efficiency as thermal generators?
I couldn't justify use of these things based on this. No real benefit for the cost. By the time I built up that scale of lava pumping and storage, I ought to have nuclear up and going anyways.
Thanks for all the info, though. I was surprised when I looked into it on my own and needed to compare notes.