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The use of water to produce electrical energy
is an extraordinary invention
made possible by gravity power plants.
A hydroelectric plant on the water
produces renewable energy from a river current.
The hydroelectric plant includes a dam,
which allows water to accumulate into a quasi-reservoir.
The more the distance between retained and open water is raised,
the greater the potential energy.
Retained water flows through underground pipes,
to be deposited on the other side of the dam.
A turbine,
for instance a Kaplan turbine, is integrated into the pipeline.
It is fitted with a propeller wheel, similar to a ship's propeller.
The steering wheel has Oriental blades,
which direct the water flow towards the moving wheel blades,
in an effective manner.
The electric motor changes the blades' direction.
Once set in motion,
the turbine drives an electric generator, which produces electricity.
The change of the blades' direction
strives to achieve a high degree of efficiency,
avoiding the inconvenience of fluctuating river water levels.
The spiral cover accelerates the water...
then, the steering wheel blades direct it toward the moving blades.
As the water hits the blades, the moving wheel drives the generator
which transforms mechanical energy into electrical energy.
Here are the components of a hydroelectric power plant
to better explain the operation.
Several installations, and the generator, are in the machine building.
With some exceptions,
a transformer raises the voltage of the current produced,
so it can be transported easier through high voltage lines.
In 1913, engineer Victor Kaplan invented the Kaplan turbine
which perfected the concept of the Francis turbine.
The efficiency of a Kaplan turbine varies generally between 90 and 95 %.
The cavitation phenomenon has been a major problem, persisting to this day.
However, today there are several solutions against cavitation,
to protect the blades of the Kaplan turbines.