Please pay attention to two very different kinds of apparatus: Hydroelectric power generators and Kelvin Water-drop generators.
Here are a few excerpts from the Wikipedia page on “hydroelectric generator”:
“Hydroelectric generators are found world-wide. In China the Three Gorges Dam generates 20,300 Megawatts and in the USA the Grand Coulee Dam generates 6,809 Megawatts.
Pico hydro is a term used for hydroelectric power generation of under 5 KW. It is useful in small, remote communities that require only a small amount of electricity. For example, to power one or two fluorescent light bulbs and a TV or radio for a few homes.[13]
Even smaller turbines of 200-300W may power a single home in a developing country with a drop of only 1 m (3 ft). Pico-hydro setups typically are run-of-the-river, meaning that dams are not used, but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before returning it to the stream.”
http://en.wikipedia.org/wiki/Hydroelectricity
The purpose of the water-dropper is not to generate electric power. A Kelvin Water-drop generator generates a high voltage potential between its two electrodes. They may be buckets or spheres, but there is no significant amount of electrical power stored on the electrodes. A fully charged sphere, for example, may cause a few micro-amperes to flow during a short-circuit arc for a few microseconds. This is not a significant amount of power and would not power a load.
Cheers,
Bobbywhy