I don't know what energy is exactly. I mean I can get how it would just be like this mathematical tool or result, but I just don't see that. Saying that seems like saying time doesn't exist, which exists, just not in the same spacial dimensions we can perceive. And then to confuse things even more, scientists, even though its not technically science even with all the mathematics, predict the existence of strings, which are suppose to be vibrating strands of energy, which means energy its a physical tangible thing in the same sense as a rock. I don't really know how to think of it. AND THEN, there's even photons, which are somehow pure "EM force", which I've heard described as pure energy AND pure momentum AND pure EM radiation.