Tevatron is STILL the “Most Powerful”
Let’s be clear.
Right now, the LHC is the particle accelerator with the highest particle beam energy (1.18 TeV), surpassing the Tevatron (0.98 TeV) by a hair.
But “power” is voltage *TIMES* current, and the Tevatron had them beat by a mile in that measure (at least for now).
The powers of these beams are proportional to:
LHC : 1.18E12 volts * 5E9 particles (~5E21)
Tevatron: 0.98E12 volts * 1E14 (or so) particles (~1E26)