This makes no sense to me. Do you think it's in a steady state now, or do you want to try to engineer it to be one? First of all, there isn't a single energy input. There are myriad inputs. You can't call it "the input" as if the current stability isn't a result of the average of the variability of each individual input. Second, humans are great at imagining that things are closed systems (in order to analyze them as closed systems) when they are not closed systems. The economic system is not by any stretch a closed system. It must interact with the political system, the environmental system, and other social systems. Stability in these interactions is a bad thing. It must be reactive, unstable, easily, rapidly upgradeable. Gold as a resource is not sustainable, because gold is present as a limited quantity, much of which we have already used up. For the good of the stability of the economy we need to stop using gold in our electronics so that we can someday switch from gold to a more sustainable imaginary renewable conductor. (hopefully one that doesn't oxidize, or become brittle like silver, copper, and aluminum.) Pass in your cell phones, folks. We need to use sustainable Dixie cups with strings instead. We'll do an experiment. I'll place 10 - 100W panels in various locations in America. I'll only place them in inhabited areas and I won't pull any funny business like putting them under a tree, or face them north, etc. I promise to give each panel the best shot at collecting the most energy. How stable will the output of each be relative to the others over a 24 hour period? Over a 7 day period? Over a 30 day period? Over a 6 month period? Over a 12 month period? My hypothesis: They won't look anything like each other. What work did I interrupt by collecting the sustained energy of the sun? Are we assuming a closed system here that is actually open? Didn't I take that energy out of the loop of a different system? How do I transmit that energy to the place I need to use it? Chemical battery? Transmission line? Thermal? All methods I know of are low on efficiency. It's really not a great source of stable instantaneous energy.