I think the point was to illustrate the difference in energy requirements for the rocket to impart to the payload. That said, re-reading Elon's article, he did

I think the point was to illustrate the difference in energy requirements for the rocket to impart to the payload. That said, re-reading Elon's article, he did explicitly say _kinetic_ energy in the 120GJ figure, in which case 0 is the right number for New Shepard at 100km.