[kjkjadksj]

We at most did things like run a mill on a river. Now compare the megawatt output of a proper modern hydroelectric project and say it isn't much energy. Imagine a society side stepping coalburning and going right to big hydro projects. Even something like a forest specifically grown and cultivated for energy is a relatively new idea, and doesn’t require any real technology even beyond understanding systems theory.

[badpun]

Big hydro requires ungodly amounts of reinforced concrete, labor (to dig millions of cubic meters on earth) and transportation capacity (gotta transport that concrete on site - hard to do with ox-powered carriages on unpaved roads). I can't see say Louis the XIV's France ever pulling that off.

[kjkjadksj]

Despite this, dams and other monumental architecture as well as complicated water management controls were built in ancient times all over the world.