Fast Enough - S1-E23
Corrected entry: At one point near the end of the episode, Professor Stein says to Barry, "That event has an energy level of at least 6.7 teraelectron volts. It cannot be stopped." One TeV is a measurement used in particle physics and is a very small amount of energy, approximately that of a very small flying insect. Hardly a proper measurement for a huge, catastrophic event.
Correction: Teraelectron volts measure particle energies, or their acceleration. The power comes from the amount of space the energy is squeezed into. The Large Hadron Collider accelerated protons to 1.18 teraelectron volts, so not much more than a mosquito, but a trillion times smaller than a mosquito, so quite powerful. The energy reading from Stein is over 5.6 times more than the world's most powerful superconducting proton synchrotron, and it's crammed into a very small space, making it nearly unstoppable.