Again, for most of agricultural history, energy was not used to grow food. The key commodity was land. The concept of energy you're referring to didn't come along until the 1800s, a couple thousand years after people invented the coin, and didn't have any real economic meaning until the industrial revolution.
I get where you're trying to go, but I just don't think it makes sense. If you're serious in trying to find some sort of fundamental thing behind money, you might read Buchan's "Frozen Desire".
I'll look into it, but, it's not true that energy was not used to grow food. Farming is labor, it takes human effort; food has to be eaten to grow more food.
You really seem to be having a hard time grasping what I'm saying. I guess I'll take one more swing at it just in case. Energy was not a commodity until the industrial revolution. If you want to say that you have your own personal conception of currency and a physics-ish notion of energy enters into that, go nuts. But as far as the actual history or common theoretical notions of money goes, it doesn't make much sense, because the concept of energy didn't exist and wasn't material to the creation of money.
