Energy in physics feels analogous to money in economics. Is a manmade medium of exchange used for convenience. It is the exchange medium between measureable physical states/things.
Is energy is real in the same way money is? An incredibly useful accounting trick that is used so frequently it feels fundamental, but really it’s just a mathmatical convenience?
Small aside: From this perspective ‘conservatipn of energy’ is a redundant statement. Of course energy must be conserved or else the equations are wrong. The definition of energy is it’s conservation.
So, what would it be a medium of, then? I mean money is a medium of exchange. And by your logic, energy is a medium of ____ ???
Exchange
I guess we can’t answer OP’s question, then. That’s too unspecific. Something gets exchanged, true. Is that man-made? Likely false, but depends on what we’re talking about.
A medium of exchange for force.
A photon of a certain wavelength imparts a known force when colliding with an electron. That force propels the electron to a higher orbital.
And how does the “manmade” tie into that? Did we make the photons? Exert the force or did we do something that brought force into existence?
We created an abstract concept that links ‘real’ phenomenon (the actual physical changes due to force). Humans created a concept that allows us to take a ton of seemingly unconnected forces and use this invented currency to predict the resultant forces.
It’s obviously a stretch, and an observed pattern, but the concept of energy is almost more of an emergent phenomenon of more fundamental properties.
I think that’s philosophy of science. We humans don’t have absolute truth. We’re just on this world and trying to figure out stuff. Our way to do it is science. And the way it works is by forming models. We observe and describe. And choose a name for the phenomenon. That’s all done by us.
“Energy” is a scientific term. And as such, it’s part of a model. A model made by us to describe what happens in the real world.
And we can use science to figure out whether things emerge from underlying things. I think with energy, a lot of that is just a measuring unit. Something being higher (potential energy) or hotter (thermal energy) or an electric field are real things. Wikipedia calls energy a “quantitative property”. But propery just means we can measure it. Not that it’s a direct force or attribute of some particle or something like that.
I’m not sure if your word “concept” is a good choice here. Energy is kind of a description of what happens and a way to quantify it. There are underlying processes(?). They add up in that way, so it’s a useful description on a higher level. But that’s kind what we do. I call mayself a human, while I’m really an agglomeration of atoms, physical and chemical processes…