This is an electricity generator that runs on water power. This generator could produce about 10 watts of power or so given adequate water flow (e.g. from a stream, small waterfall, etc.)

Water is directed through nozzles which spins a Pelton wheel which turns a NEMA 17 stepper motor (as used in many 3D printers) which generates AC electricity.

This is a parametric design. It's easy to change the size, number of nozzles, etc. and the design can be scaled-up or scaled-down to turn motors of various sizes.

I've never printed these parts, and I've never built one of these devices. But I think it would work! :)