Micro-hydro is one of the most efficient forms of
electrical power generation.
Lowest Cost per Watt of any other power generation.
It is fairly easy to predict what your output would be
year round, which can result in smaller battery sizes.
Water is used and directed into blades called a
The turbine spins and is connected to a shaft which
spins a motor, sometimes direct coupled and
sometimes using belts for converting low speed high
torque inputs to high speed low torque outputs to the
The generator, if bought is usually a DC alternator
generator. This is just an AC generator with a one way
switch on each phase.
If built, the generator is usually AC, but then sent to a
rectifier to convert it to DC.
The DC is then usable by an inverter/charger which
decides to either convert the DC to AC to be used, or to
dump it to a battery bank for storage. This same device
can convert the stored capacity to AC to be used when
generation is down.
There are other ways to use a basic charge controller
and consumer grade inverter as well. It would be a
little cheaper if you knew what to look for, but it can be
a little more complex.
Probably the best build would not be what you would call
One of the best builds would be a large waterwheel with
a gear-ratio change driven by belts or handmade gears.
The awesome thing about waterwheels is that you can
couple them up to an alternator or even a mill for
The very first thing I would do it to make my
home more efficient first.
spring, river, waterfall
Is it year round or seasonal
How far am I from the source?
For High flow applications I may go with a permanent
For low flow applications I may go with a basic
automobile alternator, requires less break over force
Typically for micro-hydro because it is easier to work
Can deal with sand and debris better
Designed for efficiency (165 degree angle into
buckets, any more will have deflected water
It is usually for higher head applications “above 20m”
These turbines are much more difficult to make
Run much faster, which allows direct coupling
Works in a wide range of speeds
This is a good one for hand building and is very easy
Has a low power output
A waterwheel with a vertical axis that came out of
Squirrel Cage design, like a hamster wheel with
Resembles the waterwheel with curved blades
Centrifugal Pumps (reverse pump turbines)
Run water backward through them and they can be
They have poor part-flow efficiency, and poor
Others would be the Francis Turbine, Propeller