While this isn't really about "renewable energy" as such, its all about natural energy which I think is totally relevant in this task, as it boils down to the workings of reality or nature, and if we understand how it works, then we have a better chance of working in harmony with is instead of against it like we as humanity are doing now. I don't know too much about Viktor Schauberger myself to be explaining anything more than that, this video does a pretty good job of introducing you to the basics, and there are 4 books which I've ordered but only one has been delivered yesterday morning so far so I've only flicked through it for a few minutes. Interesting stuff for anyone who hasn't seen it

Sacred Living Geometry -Enlightened Environmental Theories of Viktor Schauberger

"They call me deranged. The hope is that they are right! It is of no greater or lesser import for yet another fool to wander this Earth. But if I am right and science is wrong, then may the Lord God have mercy on mankind!" - Viktor Schauberger (1885-1958)