I agree that energy can be subjective. Just like in class yesterday when some people thought that the part about the labyrinths in "Garden of the Forking Paths" had a lot of energy, while other people found it really boring. However, was that because of the energy in the writing or was it just the content? I think we all have to remember that when we are trying to evaluate the energy in a piece.
Also sometimes I think authors try too hard to describe things that aren't really important. I know that having lots of details can add to the energy and that showing is definitely better than telling, but sometimes there can be too much. I think that sometimes authors kill the energy in their piece by overloading their stories with worthless details. That's something that drives me crazy when I'm reading. I guess an author has to find that happy medium where they increase the energy using descriptions, but not so much that they bore the reader to death. It's something that's a really fine line that an author has to walk.