What does Net Energy Yield has to do with economy and ecology?

Question

Since Net Energy Yield is the total useful energy produced during the lifetime of an entire energy system minus the energy used, lost, or wasted in making useful energy available. What does it have o do with economy and ecology?

Answer 1

It is actually possible to measure economic patterns through energy instead of money.

It is one of the most important ways of measuring what is happening economically without even mentioning a dollar or finances at all.

Buying energy functions almost like buying slaves in the old slave trade (muslims, romans, africans, serfs) only you don't have to feed them.
Very little happens in economic activity that is not influenced by energy. What happens to energy in a market ripples through the rest of the system's productivity and trade.

I think energy ecology goes (or will) way beyond the N.E.Y. that you mention. N.E.Y. sounds like "the ecology of DEAD energy".