Energy has always been "free". Go outside and stand in the sun. The cost of energy is related to storing it, converting it, and transporting it. Those things will not be free because they will require additional resources.

People think fossil fuel energy is expensive. Actually, it is free. No one spent a dime producing fossil fuel energy, the sun's energy was captured by plants and stored underground at no cost to anyone for millions of years.

When we extract energy from the ground, it is the first step of transporting it to a consumer. And that requires work. At some point, it might be cheaper to produce electricity using solar panel, fusion, etc. But even if the cost of converting an energy source to electricity approaches "free", the cost storing it, transporting it and converting it won't be "free".

Besides electricity there are many other limited resources including labor. Labor won't be free and so it has to be "allocated" either using the government or the market (capitalism) to do so. I don't think you have looked deeply enough into your theory.

I run my house and cars on solar, it is not "free". At present, because I avoid the storage and distribution costs of the "grid", it is cheaper than electricity bought through the grid, even if the production of the electricity costs more.