Particle accelerators live Cern or Fermilab accelerate particles like protons or electrons to speeds so close to the speed of light that talking about it in terms of speed becomes difficult and not really very useful.
For example at FermiLab in the US they have the ability to get a proton up to 99.99996% the speed of light. Imagine trying to say that in conversation - how many 9's?
So they refer to it in terms of the energy that they can put into a particle.
If you accelerate an electron through 1 volt that's an electron volt of energy.
Inside a television tube the electrons are accelerated by about 20,000eV or 20KeV
FermiLab manages 1Tev which is 1,000,000,000,000 eV or about 50 million times more than a TV.
But that's nothing next year the big collider at Cern will start up and will manage 14 times more energy than FermiLab
It's quite a beast