It depends on what one means by "real". David Hume would perhaps argue, according to "bundle theory", we experience the world through our senses and reality consists of bundles of features. We feel attributes of things, but not the thing by itself. He argued that "something" devoid of attributes doesn't exist or can even be conceived of. For example, suppose we take some honey, we can describe it as being sweet, sticky, amber in colour, doesn't go bad, tastes bitter to someone with jaundice, is odorless, etc., but these are features of honey as it interacts with ones senses and are not of honey itself; strip the honey of these features and there is nothing left. In other words, is anyone here able to think of something that exists that does not have positive attributes?
For energy, none of my senses are able to detect it directly. What are the features of energy? That which is capable of doing work? Does it "exist" in a substance? Are these scientific questions or philosophical ones?