Hydro turbines can be categorized by the water head levels, namely high, medium,
and low levels. These levels have a direct correlation with the size of turbines. Low water
head requires a large turbine, where as high water head requires a small one when compared
at the same production capacity. The main reason for differentiating the design of hydro
turbines operating at different head levels is the rotation speed of the power generator.
The turbines have to be designed accordingly to have a corresponding rotational speed to
that of the generator. Small hydropower can be divided into 3 sizes according to their
production capacities, namely small hydropower with 1-30 MW capacity, mini hydropower
with 200 kW - 1 MW capacity, and micro hydropower with capacity less than 200 kW.