It seems impossible to keep using energy and still never run out of it, or even reach a point of increasing scarcity. But just as with land and copper, there are other forces at play which make it possible for us to have increasing amounts of the services we need and desire even as we boost the demands we make upon the supplies of those resources. Advances in technology are the reason the prices of energy and other natural resources decline even as we use more of them. One saving grace is declining use of energy. Consider the steam engine, which at first operated at perhaps 1 percent efficiency.
Engines nowadays operate perhaps thirty times more efficiently.
That is, they use perhaps a thirtieth as much energy for the same result. Also important are increases in energy supply. We learn how to dig deeper, pump faster. And we invent new sources of energy, as we went from wood to coal to oil to nuclear fission. Of course nuclear fission power will be available at constant or declining costs practically forever.