Silly me - it has of course a hydro-thermal activity - spewing a plume of water into space - there should be no energy shortage.
If I understand the paper correctly - it is not volcanic in this case but a result of stresses on the surface by "tidally induced flexure during a much earlier epoch of higher orbital eccentricity"..
Thanks for that BLUELINE!

All hail to our Enceladean brethren - may they live long and prosper - until and also after we may find them!