Earlier quoted context omitted.
I’m not sure how cost effective it is. Most people don’t have a stream they can divert to run power. I’m not sure if the legality of stream diversion for personal use in many jusristrictions, and they seemed to divert a long way.
In Europe there are a lot of small streams that used to house mills before electricity made those redundant. Most of the earth work is alread done, you would just have to change it from a stretch of fast-flowing water to power a mill wheel to a small drop to power a turbine, and add the turbine and electronics. In some places there might even be ancient still-valid permits you could aquire if you buy the original mil…
On the other hand, older mills are often covered by the protection of historical monuments and can therefore not be altered as you like. This should really be looked into before buying anything as it will be an absolute showstopper with no way around it.
And if you try to do what the guy here did you'll most likely run into water way authorities with requirements for fish ladders and so on.
It's doable but it's not as easy as laying some pipe through your garden.