Micro-hydro power refers to hydroelectric systems that are less than roughly 1kW output. These systems are fairly easy to implement if you are mechanically inclined and understand basic electrical principles, but first you have to have access to a water source with a sufficient combination of elevation drop (head) and water flow rate.
A simple calculation for determining your available power is:
head (ft) x flow (gallons/minute) / 10 = power (watts)
For example, if you have access to a section of stream with a 50 ft drop in elevation from upsteam inlet to downstream out flow, and a flow rate of 30 gal/min, your available power is 50 x 30 / 10 = 150 watts.
This type of alternative power only works for people with rural properties with suitable water flow. The beauty of micro-hydro is that it provides power 24 hrs/day as long as the water is flowing.
This page from the US Dept. of Energy tells you how to calculate head and flow rates of your stream: Planning a Microhydropower System
I’ve had trouble finding a good video showing the construction of a workable system. This one shows a fun demo project with no explanation of the electrical components.
DIY microhydro power plant, facebook
The next video is part of a series which presents every phase of construction (and all the failed designs along the way) in painful detail. I am just linking the part which shows assembly of the turbine: the heart of the system. You can subscribe to the maker if you want the full experience or suffer from insomnia.
MicroHydro Series part 6, Land to House
In this video summarizing the above project, he walks through the final configuration. The notes list all the main components. This is great for seeing all the elements of a working system:
MicroHydro Series summary, Land to House
Some quick points to note:
- The recommended turbine type for microhydro is a pelton or turgo wheel which uses one or more jets of water to spin a ‘waterwheel’-type turbine at high speed. This requires high nozzle flow, not pressure.
- There can be considerable power loss due to friction in the feed pipe (penstock). This can be reduced by increasing the diameter of pipe, ensuring that it is always flowing downhill throughout its length, and keeping the length as short as possible.
- If you plan to build your own turbine, there are lots of 3D printer models for pelton turbines on thingiverse.com. Things that can be used as a generator include: a car alternator, washing machine motor, canister vacuum cleaner or shop vac motor. Most electric motors become generators by applying a rotating force to the shaft.
- You can find professionally made turbines by searching for “micro hydro turbine”.
Do lots of research before committing to a project. have fun!