We use a micro hydro system, in conjunction with about 600 watts of solar
. Although we are fortunate enough to have a small, year-round creek (maybe 100 gpm) running through our property, and while I am still enthralled by micro-hydro, I must say, it's not been as easy as I'd hoped. This is due more to my amateur enthusiasm than to any real-world, inherent problems.
Now in its third or fourth iteration, the current system is as follows; an 8" single-mold turgo-runner directly coupled to a 200vDC treadmill motor, producing somewhere around 400 watts of continous DC power at roughly 15volts.
Over the years, I've tried multiple auto alternators with some success, but the brushes on all of them could not keep up to the task. I finally bought a box of 7 treadmill motors from ebay, and have used them for various power production experiments, including the micro-hydro system.
Originally, I had no charge controllers (literally old extension cords wired to the battery bank, etc.) so it's become a bit more refined over time. Most of the issues come from our water supply. We have about 200 feet of 2" black vinyl pipe running from a small pond
(fed by the creek) and dropping about 50' vertical ft in total (50' head). The pipe changes to 1.5", then 1", then enters a single nozzle on the base of the motor where it is reduced to 1/4" before blasting the runner. The thing really hums. However, we have freezing issues and fluctuating water levels (lots in the spring, less in the winter, when its more prone to freezing...) We'd love to trench the line, but its not practical through the thick brush.
For anyone interested and with a good amount of patience and water flow, I'd recommend trying your hand at it... when its working, it's a very cool technology. Trying to thaw lines out, or running up and down the mountain 20 times a day can get frustrating, but it can be most rewarding when the batteries hit a fully charged state at 3:00 a.m. in the middle of winter. I will post pix of our homebrewed system asap, for anyone interested.