The easiest way to explain it is ...
A good is a noun. A service is a verb.
I said downthread that a good is extensive, a service is intensive.
Interesting analogies. Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
And from that ... offhand, or superficially, it looks like Power (the entirety of it) can be Modeled using Categorical Logic and Set Theory -- if one allows Triples in the latter. Bringing up the intriguing notion of using (stealing) the idea of functor from Category Mathematics as a way to handle Power-as-Supply and Power-as-Demand as across Time.
Of course, there are systems of Temporal Logic running around based on Modal Logic. I'm not convinced, yet, they are all that useful in a dynamic environment.