Small Scale Hydroelectric
Back in the early 80s, I ran across a book from the 40s which detailed how to use a car generator (not alternator) and a few 55 gallon drums to build a small hydroelectric generator. You would pair this to a small earthen or rock dam, built across a farm creek or small stream.
Saw that a company is building a modular system to do small hydro, though their webpage seems geared towards small industrial or city size units. Lowest setting on their slider pricing does $9K in electrical generation. Way bigger than most single residents would need. Still the idea of setting up a renewable energy source that doesn't kick off due to lack of sunlight or wind would be useful.
Since that earlier book I've seen small floating water turbines you could place in a stream. You could daisy chain several of them for more power. This looks more interesting for small scale: